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24 pages, 19484 KiB

Open AccessArticle

Securing Color Fidelity in 3D Architectural Heritage Scenarios

by Marco Gaiani^1,*

, Fabrizio Ivan Apollonio¹

, Andrea Ballabeni¹ and Fabio Remondino²

¹ Department of Architecture, University of Bologna, Bologna 40136, Italy

² 3D Optical Metrology (3DOM) Unit, Bruno Kessler Foundation (FBK), Trento 38123, Italy

Sensors 2017, 17(11), 2437; https://doi.org/10.3390/s17112437 - 25 Oct 2017

Cited by 35 | Viewed by 7743

Abstract

Ensuring color fidelity in image-based 3D modeling of heritage scenarios is nowadays still an open research matter. Image colors are important during the data processing as they affect algorithm outcomes, therefore their correct treatment, reduction and enhancement is fundamental. In this contribution, we [...] Read more.

Ensuring color fidelity in image-based 3D modeling of heritage scenarios is nowadays still an open research matter. Image colors are important during the data processing as they affect algorithm outcomes, therefore their correct treatment, reduction and enhancement is fundamental. In this contribution, we present an automated solution developed to improve the radiometric quality of an image datasets and the performances of two main steps of the photogrammetric pipeline (camera orientation and dense image matching). The suggested solution aims to achieve a robust automatic color balance and exposure equalization, stability of the RGB-to-gray image conversion and faithful color appearance of a digitized artifact. The innovative aspects of the article are: complete automation, better color target detection, a MATLAB implementation of the ACR scripts created by Fraser and the use of a specific weighted polynomial regression. A series of tests are presented to demonstrate the efficiency of the developed methodology and to evaluate color accuracy (‘color characterization’). Full article

(This article belongs to the Section Remote Sensors)

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15 pages, 5920 KiB

Open AccessArticle

Defect Detection of Adhesive Layer of Thermal Insulation Materials Based on Improved Particle Swarm Optimization of ECT

by Yintang Wen¹, Yao Jia², Yuyan Zhang², Xiaoyuan Luo^2,*

and Hongrui Wang²

¹ School of Science and Technology, Yanshan University, Qinhuangdao 066004, China

² School of Electrical Engineering, Yanshan University, Qinhuangdao 066004, China

Sensors 2017, 17(11), 2440; https://doi.org/10.3390/s17112440 - 25 Oct 2017

Cited by 10 | Viewed by 4505

Abstract

This paper studies the defect detection problem of adhesive layer of thermal insulation materials. A novel detection method based on an improved particle swarm optimization (PSO) algorithm of Electrical Capacitance Tomography (ECT) is presented. Firstly, a least squares support vector machine is applied [...] Read more.

This paper studies the defect detection problem of adhesive layer of thermal insulation materials. A novel detection method based on an improved particle swarm optimization (PSO) algorithm of Electrical Capacitance Tomography (ECT) is presented. Firstly, a least squares support vector machine is applied for data processing of measured capacitance values. Then, the improved PSO algorithm is proposed and applied for image reconstruction. Finally, some experiments are provided to verify the effectiveness of the proposed method in defect detection for adhesive layer of thermal insulation materials. The performance comparisons demonstrate that the proposed method has higher precision by comparing with traditional ECT algorithms. Full article

(This article belongs to the Special Issue Intelligent Sensing Technologies for Nondestructive Evaluation)

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11 pages, 909 KiB

Open AccessArticle

Chronotropic Competence Indices Extracted from Wearable Sensors for Cardiovascular Diseases Management

by Jiankang Wu^1,*, Jianan Li², Andrew Seely³, Yi Zhu², Sisi Huang², Xiaoqin Wang², Lei Zhao², Hongliang Wang¹ and Herry Christophe³

¹ The University of Chinese Academy of Sciences, Beijing 100049, China

² Jiangsu Province Hospital, No. 200 Guangzhou Road, Nanjing 210008, China

³ Ottawa Hospital Research Institute, 1053 Carling Ave, Ottawa, ON K1Y 4E9, Canada

Sensors 2017, 17(11), 2441; https://doi.org/10.3390/s17112441 - 25 Oct 2017

Cited by 5 | Viewed by 4981

Abstract

Chronotropic incompetence (CI) has been proven to be an important factor in the diagnosis and management of cardiovascular diseases. In this paper, we extend the existing CI parameters and propose chronotropic competence indices (CCI) to describe the exercise response of the cardiopulmonary system. [...] Read more.

Chronotropic incompetence (CI) has been proven to be an important factor in the diagnosis and management of cardiovascular diseases. In this paper, we extend the existing CI parameters and propose chronotropic competence indices (CCI) to describe the exercise response of the cardiopulmonary system. A cardiac chronotropic competence Test (3CT), dedicated to CCI measurement using a wearable device, is also presented. Preliminary clinical trials are presented for the validation of 3CT measurement accuracy, and to show the potential of CCI in the prevention and rehabilitation of cardiovascular diseases. Full article

(This article belongs to the Special Issue Sensors and Analytics for Precision Medicine)

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22 pages, 10709 KiB

Open AccessArticle

Visual Localization across Seasons Using Sequence Matching Based on Multi-Feature Combination

by Yongliang Qiao^*

, Cindy Cappelle and Yassine Ruichek

Le2i FRE2005, CNRS, Arts et Métiers, UBFC, Université de technologie de Belfort-Montbéliard, Belfort 90000, France

Sensors 2017, 17(11), 2442; https://doi.org/10.3390/s17112442 - 25 Oct 2017

Cited by 18 | Viewed by 5753

Abstract

Visual localization is widely used in autonomous navigation system and Advanced Driver Assistance Systems (ADAS). However, visual-based localization in seasonal changing situations is one of the most challenging topics in computer vision and the intelligent vehicle community. The difficulty of this task is [...] Read more.

Visual localization is widely used in autonomous navigation system and Advanced Driver Assistance Systems (ADAS). However, visual-based localization in seasonal changing situations is one of the most challenging topics in computer vision and the intelligent vehicle community. The difficulty of this task is related to the strong appearance changes that occur in scenes due to weather or season changes. In this paper, a place recognition based visual localization method is proposed, which realizes the localization by identifying previously visited places using the sequence matching method. It operates by matching query image sequences to an image database acquired previously (video acquired during traveling period). In this method, in order to improve matching accuracy, multi-feature is constructed by combining a global GIST descriptor and local binary feature CSLBP (Center-symmetric local binary patterns) to represent image sequence. Then, similarity measurement according to Chi-square distance is used for effective sequences matching. For experimental evaluation, the relationship between image sequence length and sequences matching performance is studied. To show its effectiveness, the proposed method is tested and evaluated in four seasons outdoor environments. The results have shown improved precision–recall performance against the state-of-the-art SeqSLAM algorithm. Full article

(This article belongs to the Special Issue Sensors, Wireless Connectivity and Systems for Autonomous Vehicles and Smart Mobility)

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15 pages, 1847 KiB

Open AccessArticle

Towards Intelligent Interpretation of Low Strain Pile Integrity Testing Results Using Machine Learning Techniques

by De-Mi Cui¹, Weizhong Yan^2,*

, Xiao-Quan Wang¹ and Lie-Min Lu¹

¹ Anhui and Huaihe River Institute of Hydraulic Research, No. 771 Zhihuai Road, Bengbu 233000, China

² GE Global Research Center, Niskayuna, New York, NY 12309, USA

Sensors 2017, 17(11), 2443; https://doi.org/10.3390/s17112443 - 25 Oct 2017

Cited by 16 | Viewed by 9296

Abstract

Low strain pile integrity testing (LSPIT), due to its simplicity and low cost, is one of the most popular NDE methods used in pile foundation construction. While performing LSPIT in the field is generally quite simple and quick, determining the integrity of the [...] Read more.

Low strain pile integrity testing (LSPIT), due to its simplicity and low cost, is one of the most popular NDE methods used in pile foundation construction. While performing LSPIT in the field is generally quite simple and quick, determining the integrity of the test piles by analyzing and interpreting the test signals (reflectograms) is still a manual process performed by experienced experts only. For foundation construction sites where the number of piles to be tested is large, it may take days before the expert can complete interpreting all of the piles and delivering the integrity assessment report. Techniques that can automate test signal interpretation, thus shortening the LSPIT’s turnaround time, are of great business value and are in great need. Motivated by this need, in this paper, we develop a computer-aided reflectogram interpretation (CARI) methodology that can interpret a large number of LSPIT signals quickly and consistently. The methodology, built on advanced signal processing and machine learning technologies, can be used to assist the experts in performing both qualitative and quantitative interpretation of LSPIT signals. Specifically, the methodology can ease experts’ interpretation burden by screening all test piles quickly and identifying a small number of suspected piles for experts to perform manual, in-depth interpretation. We demonstrate the methodology’s effectiveness using the LSPIT signals collected from a number of real-world pile construction sites. The proposed methodology can potentially enhance LSPIT and make it even more efficient and effective in quality control of deep foundation construction. Full article

(This article belongs to the Special Issue Intelligent Sensing Technologies for Nondestructive Evaluation)

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16 pages, 2585 KiB

Open AccessArticle

Linear Extended State Observer-Based Motion Synchronization Control for Hybrid Actuation System of More Electric Aircraft

by Xingjian Wang^*

, Rui Liao, Cun Shi and Shaoping Wang

School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China

Sensors 2017, 17(11), 2444; https://doi.org/10.3390/s17112444 - 25 Oct 2017

Cited by 36 | Viewed by 9356

Abstract

Moving towards the more electric aircraft (MEA), a hybrid actuator configuration provides an opportunity to introduce electromechanical actuator (EMA) into primary flight control. In the hybrid actuation system (HAS), an electro-hydraulic servo actuator (EHSA) and an EMA operate on the same control surface. [...] Read more.

Moving towards the more electric aircraft (MEA), a hybrid actuator configuration provides an opportunity to introduce electromechanical actuator (EMA) into primary flight control. In the hybrid actuation system (HAS), an electro-hydraulic servo actuator (EHSA) and an EMA operate on the same control surface. In order to solve force fighting problem in HAS, this paper proposes a novel linear extended state observer (LESO)-based motion synchronization control method. To cope with the problem of unavailability of the state signals required by the motion synchronization controller, LESO is designed for EHSA and EMA to observe the state variables. Based on the observed states of LESO, motion synchronization controllers could enable EHSA and EMA to simultaneously track the desired motion trajectories. Additionally, nonlinearities, uncertainties and unknown disturbances as well as the coupling term between EHSA and EMA can be estimated and compensated by using the extended state of the proposed LESO. Finally, comparative simulation results indicate that the proposed LESO-based motion synchronization controller could reduce significant force fighting between EHSA and EMA. Full article

(This article belongs to the Special Issue Mechatronic Systems for Automatic Vehicles)

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14 pages, 2975 KiB

Open AccessArticle

Arrhythmia Evaluation in Wearable ECG Devices

by Muammar Sadrawi¹, Chien-Hung Lin², Yin-Tsong Lin²

, Yita Hsieh², Chia-Chun Kuo², Jen Chien Chien², Koichi Haraikawa², Maysam F. Abbod³

and Jiann-Shing Shieh^1,*

¹ Department of Mechanical Engineering and Innovation Center for Big Data and Digital Convergence, Yuan Ze University, Taoyuan, Chung-Li 32003, Taiwan

² Healthcare and Beauty RD Center, Kinpo Electronics, Inc., New Taipei City 222, Taiwan

³ Department of Electronic and Computer Engineering, Brunel University London, Uxbridge UB8 3PH, UK

Sensors 2017, 17(11), 2445; https://doi.org/10.3390/s17112445 - 25 Oct 2017

Cited by 42 | Viewed by 11712

Abstract

This study evaluates four databases from PhysioNet: The American Heart Association database (AHADB), Creighton University Ventricular Tachyarrhythmia database (CUDB), MIT-BIH Arrhythmia database (MITDB), and MIT-BIH Noise Stress Test database (NSTDB). The ANSI/AAMI EC57:2012 is used for the evaluation of the algorithms for the [...] Read more.

This study evaluates four databases from PhysioNet: The American Heart Association database (AHADB), Creighton University Ventricular Tachyarrhythmia database (CUDB), MIT-BIH Arrhythmia database (MITDB), and MIT-BIH Noise Stress Test database (NSTDB). The ANSI/AAMI EC57:2012 is used for the evaluation of the algorithms for the supraventricular ectopic beat (SVEB), ventricular ectopic beat (VEB), atrial fibrillation (AF), and ventricular fibrillation (VF) via the evaluation of the sensitivity, positive predictivity and false positive rate. Sample entropy, fast Fourier transform (FFT), and multilayer perceptron neural network with backpropagation training algorithm are selected for the integrated detection algorithms. For this study, the result for SVEB has some improvements compared to a previous study that also utilized ANSI/AAMI EC57. In further, VEB sensitivity and positive predictivity gross evaluations have greater than 80%, except for the positive predictivity of the NSTDB database. For AF gross evaluation of MITDB database, the results show very good classification, excluding the episode sensitivity. In advanced, for VF gross evaluation, the episode sensitivity and positive predictivity for the AHADB, MITDB, and CUDB, have greater than 80%, except for MITDB episode positive predictivity, which is 75%. The achieved results show that the proposed integrated SVEB, VEB, AF, and VF detection algorithm has an accurate classification according to ANSI/AAMI EC57:2012. In conclusion, the proposed integrated detection algorithm can achieve good accuracy in comparison with other previous studies. Furthermore, more advanced algorithms and hardware devices should be performed in future for arrhythmia detection and evaluation. Full article

(This article belongs to the Special Issue Biomedical Sensors and Systems 2017)

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17 pages, 3737 KiB

Open AccessArticle

Magnetoelectric Transverse Gradient Sensor with High Detection Sensitivity and Low Gradient Noise

by Mingji Zhang^1,2

and Siu Wing Or^1,2,*

¹ Department of Electrical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China

² Hong Kong Branch of National Rail Transit Electrification and Automation Engineering Technology Research Center, Hong Kong, China

Sensors 2017, 17(11), 2446; https://doi.org/10.3390/s17112446 - 25 Oct 2017

Cited by 8 | Viewed by 6040

Abstract

We report, theoretically and experimentally, the realization of a high detection performance in a novel magnetoelectric (ME) transverse gradient sensor based on the large ME effect and the magnetic field gradient (MFG) technique in a pair of magnetically-biased, electrically-shielded, and mechanically-enclosed ME composites [...] Read more.

We report, theoretically and experimentally, the realization of a high detection performance in a novel magnetoelectric (ME) transverse gradient sensor based on the large ME effect and the magnetic field gradient (MFG) technique in a pair of magnetically-biased, electrically-shielded, and mechanically-enclosed ME composites having a transverse orientation and an axial separation. The output voltage of the gradient sensor is directly obtained from the transverse MFG-induced difference in ME voltage between the two ME composites and is calibrated against transverse MFGs to give a high detection sensitivity of 0.4–30.6 V/(T/m), a strong common-mode magnetic field noise rejection rate of <−14.5 dB, a small input-output nonlinearity of <10 ppm, and a low gradient noise of 0.16–620 nT/m/

\sqrt{Hz}

in a broad frequency range of 1 Hz–170 kHz under a small baseline of 35 mm. An analysis of experimental gradient noise spectra obtained in a magnetically-unshielded laboratory environment reveals the domination of the pink (1/f) noise, dielectric loss noise, and power-frequency noise below 3 kHz, in addition to the circuit noise above 3 kHz, in the gradient sensor. The high detection performance, together with the added merit of passive and direct ME conversion by the large ME effect in the ME composites, makes the gradient sensor suitable for the passive, direct, and broadband detection of transverse MFGs. Full article

(This article belongs to the Special Issue Magnetic Sensors and Their Applications)

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17 pages, 9402 KiB

Open AccessArticle

Dolphin Sounds-Inspired Covert Underwater Acoustic Communication and Micro-Modem

by Gang Qiao^1,2,†, Yunjiang Zhao^1,2,†

, Songzuo Liu^1,2,*,† and Muhammad Bilal^1,2,†

¹ Acoustic Science and Technology Laboratory, Harbin Engineering University, Harbin 150001, China

² College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2447; https://doi.org/10.3390/s17112447 - 25 Oct 2017

Cited by 25 | Viewed by 10833

Abstract

A novel portable underwater acoustic modem is proposed in this paper for covert communication between divers or underwater unmanned vehicles (UUVs) and divers at a short distance. For the first time, real dolphin calls are used in the modem to realize biologically inspired [...] Read more.

A novel portable underwater acoustic modem is proposed in this paper for covert communication between divers or underwater unmanned vehicles (UUVs) and divers at a short distance. For the first time, real dolphin calls are used in the modem to realize biologically inspired Covert Underwater Acoustic Communication (CUAC). A variety of dolphin whistles and clicks stored in an SD card inside the modem helps to realize different biomimetic CUAC algorithms based on the specified covert scenario. In this paper, the information is conveyed during the time interval between dolphin clicks. TMS320C6748 and TLV320AIC3106 are the core processors used in our unique modem for fast digital processing and interconnection with other terminals or sensors. Simulation results show that the bit error rate (BER) of the CUAC algorithm is less than 10

^{- 5}

when the signal to noise ratio is over ‒5 dB. The modem was tested in an underwater pool, and a data rate of 27.1 bits per second at a distance of 10 m was achieved. Full article

(This article belongs to the Section Sensor Networks)

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23 pages, 953 KiB

Open AccessArticle

Noise Maps for Quantitative and Clinical Severity Towards Long-Term ECG Monitoring

by Estrella Everss-Villalba¹

, Francisco Manuel Melgarejo-Meseguer¹, Manuel Blanco-Velasco²

, Francisco Javier Gimeno-Blanes³

, Salvador Sala-Pla⁴, José Luis Rojo-Álvarez^5,6

and Arcadi García-Alberola^1,*

¹ Cardiology Service, Arrhythmia Unit, Hospital General Universitario Virgen de la Arrixaca, El Palmar, Murcia 30120, Spain

² Department of Signal Theory and Communications, University of de Alcalá, Alcalá de Henares, Madrid 28805, Spain

³ Department of Signal Theory and Communications, Miguel Hernández University, Elche, Alicante 03202, Spain

⁴ Instituto de Neurociencias, Miguel Hernández University–CSIC, Alicante 03550, Spain

⁵ Department of Signal Theory and Communications, Rey Juan Carlos University, Fuenlabrada, Madrid 28943, Spain

⁶ Center for Computational Simulation, Universidad Politécnica de Madrid, Boadilla, Madrid 28223, Spain

Sensors 2017, 17(11), 2448; https://doi.org/10.3390/s17112448 - 25 Oct 2017

Cited by 28 | Viewed by 6404

Abstract

Noise and artifacts are inherent contaminating components and are particularly present in Holter electrocardiogram (ECG) monitoring. The presence of noise is even more significant in long-term monitoring (LTM) recordings, as these are collected for several days in patients following their daily activities; hence, [...] Read more.

Noise and artifacts are inherent contaminating components and are particularly present in Holter electrocardiogram (ECG) monitoring. The presence of noise is even more significant in long-term monitoring (LTM) recordings, as these are collected for several days in patients following their daily activities; hence, strong artifact components can temporarily impair the clinical measurements from the LTM recordings. Traditionally, the noise presence has been dealt with as a problem of non-desirable component removal by means of several quantitative signal metrics such as the signal-to-noise ratio (SNR), but current systems do not provide any information about the true impact of noise on the ECG clinical evaluation. As a first step towards an alternative to classical approaches, this work assesses the ECG quality under the assumption that an ECG has good quality when it is clinically interpretable. Therefore, our hypotheses are that it is possible (a) to create a clinical severity score for the effect of the noise on the ECG, (b) to characterize its consistency in terms of its temporal and statistical distribution, and (c) to use it for signal quality evaluation in LTM scenarios. For this purpose, a database of external event recorder (EER) signals is assembled and labeled from a clinical point of view for its use as the gold standard of noise severity categorization. These devices are assumed to capture those signal segments more prone to be corrupted with noise during long-term periods. Then, the ECG noise is characterized through the comparison of these clinical severity criteria with conventional quantitative metrics taken from traditional noise-removal approaches, and noise maps are proposed as a novel representation tool to achieve this comparison. Our results showed that neither of the benchmarked quantitative noise measurement criteria represent an accurate enough estimation of the clinical severity of the noise. A case study of long-term ECG is reported, showing the statistical and temporal correspondences and properties with respect to EER signals used to create the gold standard for clinical noise. The proposed noise maps, together with the statistical consistency of the characterization of the noise clinical severity, paves the way towards forthcoming systems providing us with noise maps of the noise clinical severity, allowing the user to process different ECG segments with different techniques and in terms of different measured clinical parameters. Full article

(This article belongs to the Special Issue Sensors for Health Monitoring and Disease Diagnosis)

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17 pages, 2402 KiB

Open AccessArticle

A Robust Dynamic Heart-Rate Detection Algorithm Framework During Intense Physical Activities Using Photoplethysmographic Signals

by Jiajia Song^1,2, Dan Li^2,*, Xiaoyuan Ma^2,3, Guowei Teng¹ and Jianming Wei²

¹ School of Communication and Information Engineering, Shanghai University, Shanghai 200444, China

² Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China

³ University of Chinese Academy of Sciences, Beijing 100049, China

Sensors 2017, 17(11), 2450; https://doi.org/10.3390/s17112450 - 25 Oct 2017

Cited by 16 | Viewed by 6020

Abstract

Dynamic accurate heart-rate (HR) estimation using a photoplethysmogram (PPG) during intense physical activities is always challenging due to corruption by motion artifacts (MAs). It is difficult to reconstruct a clean signal and extract HR from contaminated PPG. This paper proposes a robust HR-estimation [...] Read more.

Dynamic accurate heart-rate (HR) estimation using a photoplethysmogram (PPG) during intense physical activities is always challenging due to corruption by motion artifacts (MAs). It is difficult to reconstruct a clean signal and extract HR from contaminated PPG. This paper proposes a robust HR-estimation algorithm framework that uses one-channel PPG and tri-axis acceleration data to reconstruct the PPG and calculate the HR based on features of the PPG and spectral analysis. Firstly, the signal is judged by the presence of MAs. Then, the spectral peaks corresponding to acceleration data are filtered from the periodogram of the PPG when MAs exist. Different signal-processing methods are applied based on the amount of remaining PPG spectral peaks. The main MA-removal algorithm (NFEEMD) includes the repeated single-notch filter and ensemble empirical mode decomposition. Finally, HR calibration is designed to ensure the accuracy of HR tracking. The NFEEMD algorithm was performed on the 23 datasets from the 2015 IEEE Signal Processing Cup Database. The average estimation errors were 1.12 BPM (12 training datasets), 2.63 BPM (10 testing datasets) and 1.87 BPM (all 23 datasets), respectively. The Pearson correlation was 0.992. The experiment results illustrate that the proposed algorithm is not only suitable for HR estimation during continuous activities, like slow running (13 training datasets), but also for intense physical activities with acceleration, like arm exercise (10 testing datasets). Full article

(This article belongs to the Special Issue Sensors for Health Monitoring and Disease Diagnosis)

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14 pages, 6186 KiB

Open AccessArticle

3-Axis Fully-Integrated Capacitive Tactile Sensor with Flip-Bonded CMOS on LTCC Interposer

by Sho Asano^1,*, Masanori Muroyama²

, Takahiro Nakayama³, Yoshiyuki Hata⁴, Yutaka Nonomura⁴

and Shuji Tanaka¹

¹ Department of Robotics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan

² Micro System Integration Center, Tohoku University, 519-1176 Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-0845, Japan

³ Partner Robot Division, Toyota Motor Corporation, 543 Kirigahora, Nishi-hirose-cho, Toyota, Aichi 470-0309, Japan

⁴ System & Electronics Engineering Dept. III, Toyota Central R & D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan

Sensors 2017, 17(11), 2451; https://doi.org/10.3390/s17112451 - 25 Oct 2017

Cited by 32 | Viewed by 8550

Abstract

This paper reports a 3-axis fully integrated differential capacitive tactile sensor surface-mountable on a bus line. The sensor integrates a flip-bonded complementary metal-oxide semiconductor (CMOS) with capacitive sensing circuits on a low temperature cofired ceramic (LTCC) interposer with Au through vias by Au-Au [...] Read more.

This paper reports a 3-axis fully integrated differential capacitive tactile sensor surface-mountable on a bus line. The sensor integrates a flip-bonded complementary metal-oxide semiconductor (CMOS) with capacitive sensing circuits on a low temperature cofired ceramic (LTCC) interposer with Au through vias by Au-Au thermo-compression bonding. The CMOS circuit and bonding pads on the sensor backside were electrically connected through Au bumps and the LTCC interposer, and the differential capacitive gap was formed by an Au sealing frame. A diaphragm for sensing 3-axis force was formed in the CMOS substrate. The dimensions of the completed sensor are 2.5 mm in width, 2.5 mm in length, and 0.66 mm in thickness. The fabricated sensor output coded 3-axis capacitive sensing data according to applied 3-axis force by three-dimensional (3D)-printed pins. The measured sensitivity was as high as over 34 Count/mN for normal force and 14 to 15 Count/mN for shear force with small noise, which corresponds to less than 1 mN. The hysteresis and the average cross-sensitivity were also found to be less than 2% full scale and 11%, respectively. Full article

(This article belongs to the Special Issue Tactile Sensors and Sensing)

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11 pages, 3263 KiB

Open AccessArticle

Surface Acoustic Wave (SAW)-Enhanced Chemical Functionalization of Gold Films

by Gina Greco¹, Matteo Agostini^1,2

, Richie Shilton², Marco Travagliati^1,2,†

, Giovanni Signore^1,2 and Marco Cecchini^1,*

¹ National Enterprise for nanoScience and nanoTechnology (NEST), Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy

² Center for Nanotechnology Innovation@NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56127 Pisa, Italy

^† Present Address: Menarini Silicon Biosystems SpA, Via di Vittorio 21/B3, 40013 Castel Maggiore (BO), Italy.

Sensors 2017, 17(11), 2452; https://doi.org/10.3390/s17112452 - 26 Oct 2017

Cited by 12 | Viewed by 6439

Abstract

Surface chemical and biochemical functionalization is a fundamental process that is widely applied in many fields to add new functions, features, or capabilities to a material’s surface. Here, we demonstrate that surface acoustic waves (SAWs) can enhance the chemical functionalization of gold films. [...] Read more.

Surface chemical and biochemical functionalization is a fundamental process that is widely applied in many fields to add new functions, features, or capabilities to a material’s surface. Here, we demonstrate that surface acoustic waves (SAWs) can enhance the chemical functionalization of gold films. This is shown by using an integrated biochip composed by a microfluidic channel coupled to a surface plasmon resonance (SPR) readout system and by monitoring the adhesion of biotin-thiol on the gold SPR areas in different conditions. In the case of SAW-induced streaming, the functionalization efficiency is improved

\approx 5

times with respect to the case without SAWs. The technology here proposed can be easily applied to a wide variety of biological systems (e.g., proteins, nucleic acids) and devices (e.g., sensors, devices for cell cultures). Full article

(This article belongs to the Special Issue Surface Plasmon Resonance Sensing)

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18 pages, 7013 KiB

Open AccessArticle

Prostate Cancer Detection with a Tactile Resonance Sensor—Measurement Considerations and Clinical Setup

by Anders P. Åstrand^1,2,*, Britt M. Andersson^1,2, Ville Jalkanen^1,2, Börje Ljungberg³, Anders Bergh⁴ and Olof A. Lindahl^2,5

¹ Department of Applied Physics and Electronics, Umeå University, SE-90187 Umeå, Sweden

² Centre for Biomedical Engineering and Physics, Umeå University, SE-90187 Umeå, Sweden

³ Department of Surgical and Perioperative Science, Urology and Andrology, Umeå University, SE-90187 Umeå, Sweden

⁴ Department of Medical Biosciences, Pathology, Umeå University, SE-90187 Umeå, Sweden

⁵ Department of Radiation Sciences, Biomedical Engineering, Umeå University, SE-90187 Umeå, Sweden

Sensors 2017, 17(11), 2453; https://doi.org/10.3390/s17112453 - 26 Oct 2017

Cited by 14 | Viewed by 10571

Abstract

Tumors in the human prostate are usually stiffer compared to surrounding non-malignant glandular tissue, and tactile resonance sensors measuring stiffness can be used to detect prostate cancer. To explore this further, we used a tactile resonance sensor system combined with a rotatable sample [...] Read more.

Tumors in the human prostate are usually stiffer compared to surrounding non-malignant glandular tissue, and tactile resonance sensors measuring stiffness can be used to detect prostate cancer. To explore this further, we used a tactile resonance sensor system combined with a rotatable sample holder where whole surgically removed prostates could be attached to detect tumors on, and beneath, the surface ex vivo. Model studies on tissue phantoms made of silicone and porcine tissue were performed. Finally, two resected human prostate glands were studied. Embedded stiff silicone inclusions placed 4 mm under the surface could be detected in both the silicone and biological tissue models, with a sensor indentation of 0.6 mm. Areas with different amounts of prostate cancer (PCa) could be distinguished from normal tissue (p < 0.05), when the tumor was located in the anterior part, whereas small tumors located in the dorsal aspect were undetected. The study indicates that PCa may be detected in a whole resected prostate with an uneven surface and through its capsule. This is promising for the development of a clinically useful instrument to detect prostate cancer during surgery. Full article

(This article belongs to the Special Issue Tactile Sensors and Sensing)

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18 pages, 17979 KiB

Open AccessArticle

Precise Aperture-Dependent Motion Compensation with Frequency Domain Fast Back-Projection Algorithm

by Man Zhang¹, Guanyong Wang^2,3,*

and Lei Zhang^2,*

¹ School of Software, Xidian University, Xi’an 710071, China

² National Laboratory of Radar Signal Processing, Collaborative Innovation Center of Information Sensing and Understanding, Xidian University, Xi’an 710071, China

³ Beijing Institute of Radio Measurement, The Second Academy of China Aerospace Science and Industry Corporation (CASIC), Beijing 100854, China

Sensors 2017, 17(11), 2454; https://doi.org/10.3390/s17112454 - 26 Oct 2017

Cited by 9 | Viewed by 4717

Abstract

Precise azimuth-variant motion compensation (MOCO) is an essential and difficult task for high-resolution synthetic aperture radar (SAR) imagery. In conventional post-filtering approaches, residual azimuth-variant motion errors are generally compensated through a set of spatial post-filters, where the coarse-focused image is segmented into overlapped [...] Read more.

Precise azimuth-variant motion compensation (MOCO) is an essential and difficult task for high-resolution synthetic aperture radar (SAR) imagery. In conventional post-filtering approaches, residual azimuth-variant motion errors are generally compensated through a set of spatial post-filters, where the coarse-focused image is segmented into overlapped blocks concerning the azimuth-dependent residual errors. However, image domain post-filtering approaches, such as precise topography- and aperture-dependent motion compensation algorithm (PTA), have difficulty of robustness in declining, when strong motion errors are involved in the coarse-focused image. In this case, in order to capture the complete motion blurring function within each image block, both the block size and the overlapped part need necessary extension leading to degeneration of efficiency and robustness inevitably. Herein, a frequency domain fast back-projection algorithm (FDFBPA) is introduced to deal with strong azimuth-variant motion errors. FDFBPA disposes of the azimuth-variant motion errors based on a precise azimuth spectrum expression in the azimuth wavenumber domain. First, a wavenumber domain sub-aperture processing strategy is introduced to accelerate computation. After that, the azimuth wavenumber spectrum is partitioned into a set of wavenumber blocks, and each block is formed into a sub-aperture coarse resolution image via the back-projection integral. Then, the sub-aperture images are straightforwardly fused together in azimuth wavenumber domain to obtain a full resolution image. Moreover, chirp-Z transform (CZT) is also introduced to implement the sub-aperture back-projection integral, increasing the efficiency of the algorithm. By disusing the image domain post-filtering strategy, robustness of the proposed algorithm is improved. Both simulation and real-measured data experiments demonstrate the effectiveness and superiority of the proposal. Full article

(This article belongs to the Special Issue Synthetic Aperture Radar (SAR) Technology: New Perspectives Offered by New-Generation and Forthcoming SAR Sensors)

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15 pages, 7386 KiB

Open AccessArticle

Inferring Interaction Force from Visual Information without Using Physical Force Sensors

by Wonjun Hwang¹

and Soo-Chul Lim^2,*

¹ Department of Software and Computer Engineering, Ajou University, 206 Worldcup-ro, Yeongtong-gu, Suwon 16499, Korea

² Department of Mechanical, Robotics and Energy Engineering, Dongguk University, 30, Pildong-ro 1gil, Jung-gu, Seoul 04620, Korea

Sensors 2017, 17(11), 2455; https://doi.org/10.3390/s17112455 - 26 Oct 2017

Cited by 47 | Viewed by 5735

Abstract

In this paper, we present an interaction force estimation method that uses visual information rather than that of a force sensor. Specifically, we propose a novel deep learning-based method utilizing only sequential images for estimating the interaction force against a target object, where [...] Read more.

In this paper, we present an interaction force estimation method that uses visual information rather than that of a force sensor. Specifically, we propose a novel deep learning-based method utilizing only sequential images for estimating the interaction force against a target object, where the shape of the object is changed by an external force. The force applied to the target can be estimated by means of the visual shape changes. However, the shape differences in the images are not very clear. To address this problem, we formulate a recurrent neural network-based deep model with fully-connected layers, which models complex temporal dynamics from the visual representations. Extensive evaluations show that the proposed learning models successfully estimate the interaction forces using only the corresponding sequential images, in particular in the case of three objects made of different materials, a sponge, a PET bottle, a human arm, and a tube. The forces predicted by the proposed method are very similar to those measured by force sensors. Full article

(This article belongs to the Section Physical Sensors)

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8 pages, 1613 KiB

Open AccessArticle

Modeling of Thermal Phase Noise in a Solid Core Photonic Crystal Fiber-Optic Gyroscope

by Ningfang Song, Kun Ma, Jing Jin^*, Fei Teng and Wei Cai

Department of Opto-electronics Engineering, Beihang University, Beijing 100191, China

Sensors 2017, 17(11), 2456; https://doi.org/10.3390/s17112456 - 26 Oct 2017

Cited by 7 | Viewed by 6189

Abstract

A theoretical model of the thermal phase noise in a square-wave modulated solid core photonic crystal fiber-optic gyroscope has been established, and then verified by measurements. The results demonstrate a good agreement between theory and experiment. The contribution of the thermal phase noise [...] Read more.

A theoretical model of the thermal phase noise in a square-wave modulated solid core photonic crystal fiber-optic gyroscope has been established, and then verified by measurements. The results demonstrate a good agreement between theory and experiment. The contribution of the thermal phase noise to the random walk coefficient of the gyroscope is derived. A fiber coil with 2.8 km length is used in the experimental solid core photonic crystal fiber-optic gyroscope, showing a random walk coefficient of 9.25 × 10⁻⁵ deg/√h. Full article

(This article belongs to the Special Issue Integrated Photonic Technologies for Sensing Applications)

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22 pages, 2541 KiB

Open AccessArticle

ESPRIT-Like Two-Dimensional DOA Estimation for Monostatic MIMO Radar with Electromagnetic Vector Received Sensors under the Condition of Gain and Phase Uncertainties and Mutual Coupling

by Dong Zhang^1,*

, Yongshun Zhang¹, Guimei Zheng¹, Cunqian Feng¹ and Jun Tang²

¹ Air and Missile Defense College, Air Force Engineering University, Xi’an 710051, China

² Department of Electronic Engineering, Tsinghua University, Beijing 100084, China

Sensors 2017, 17(11), 2457; https://doi.org/10.3390/s17112457 - 26 Oct 2017

Cited by 11 | Viewed by 4475

Abstract

In this paper, we focus on the problem of two-dimensional direction of arrival (2D-DOA) estimation for monostatic MIMO Radar with electromagnetic vector received sensors (MIMO-EMVSs) under the condition of gain and phase uncertainties (GPU) and mutual coupling (MC). GPU would spoil the invariance [...] Read more.

In this paper, we focus on the problem of two-dimensional direction of arrival (2D-DOA) estimation for monostatic MIMO Radar with electromagnetic vector received sensors (MIMO-EMVSs) under the condition of gain and phase uncertainties (GPU) and mutual coupling (MC). GPU would spoil the invariance property of the EMVSs in MIMO-EMVSs, thus the effective ESPRIT algorithm unable to be used directly. Then we put forward a C-SPD ESPRIT-like algorithm. It estimates the 2D-DOA and polarization station angle (PSA) based on the instrumental sensors method (ISM). The C-SPD ESPRIT-like algorithm can obtain good angle estimation accuracy without knowing the GPU. Furthermore, it can be applied to arbitrary array configuration and has low complexity for avoiding the angle searching procedure. When MC and GPU exist together between the elements of EMVSs, in order to make our algorithm feasible, we derive a class of separated electromagnetic vector receiver and give the S-SPD ESPRIT-like algorithm. It can solve the problem of GPU and MC efficiently. And the array configuration can be arbitrary. The effectiveness of our proposed algorithms is verified by the simulation result. Full article

(This article belongs to the Special Issue Advanced Electronic Devices, Circuits, and Signal Processing for Biomedical Sensors Application)

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19 pages, 2017 KiB

Open AccessArticle

Soft Sensing of Non-Newtonian Fluid Flow in Open Venturi Channel Using an Array of Ultrasonic Level Sensors—AI Models and Their Validations

by Khim Chhantyal^*

, Håkon Viumdal^† and Saba Mylvaganam^†

¹ Faculty of Technology, Natural Sciences, and Maritime Sciences, University College of Southeast Norway, Kjølnes Ring 56, 3918 Porsgrunn, Norway

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2458; https://doi.org/10.3390/s17112458 - 26 Oct 2017

Cited by 11 | Viewed by 5996

Abstract

In oil and gas and geothermal installations, open channels followed by sieves for removal of drill cuttings, are used to monitor the quality and quantity of the drilling fluids. Drilling fluid flow rate is difficult to measure due to the varying flow conditions [...] Read more.

In oil and gas and geothermal installations, open channels followed by sieves for removal of drill cuttings, are used to monitor the quality and quantity of the drilling fluids. Drilling fluid flow rate is difficult to measure due to the varying flow conditions (e.g., wavy, turbulent and irregular) and the presence of drilling cuttings and gas bubbles. Inclusion of a Venturi section in the open channel and an array of ultrasonic level sensors above it at locations in the vicinity of and above the Venturi constriction gives the varying levels of the drilling fluid in the channel. The time series of the levels from this array of ultrasonic level sensors are used to estimate the drilling fluid flow rate, which is compared with Coriolis meter measurements. Fuzzy logic, neural networks and support vector regression algorithms applied to the data from temporal and spatial ultrasonic level measurements of the drilling fluid in the open channel give estimates of its flow rate with sufficient reliability, repeatability and uncertainty, providing a novel soft sensing of an important process variable. Simulations, cross-validations and experimental results show that feedforward neural networks with the Bayesian regularization learning algorithm provide the best flow rate estimates. Finally, the benefits of using this soft sensing technique combined with Venturi constriction in open channels are discussed. Full article

(This article belongs to the Special Issue Soft Sensors and Intelligent Algorithms for Data Fusion)

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9 pages, 1657 KiB

Open AccessArticle

Waveguide Bragg Gratings in Ormocer^®s for Temperature Sensing

by Maiko Girschikofsky^1,*, Manuel Rosenberger¹, Michael Förthner², Mathias Rommel³

, Lothar Frey^2,3 and Ralf Hellmann¹

¹ Applied Laser and Photonics Group, University of Applied Sciences Aschaffenburg, 63743 Aschaffenburg, Germany

² Chair of Electron Devices, Friedrich-Alexander University Erlangen, 91058 Erlangen, Germany

³ Fraunhofer Institute for Integrated Systems and Device Technology (IISB) Erlangen, 91058 Erlangen, Germany

Sensors 2017, 17(11), 2459; https://doi.org/10.3390/s17112459 - 26 Oct 2017

Cited by 18 | Viewed by 6193

Abstract

Embedded channel waveguide Bragg gratings are fabricated in the Ormocer^® hybrid polymers OrmoComp^®, OrmoCore, and OrmoClad by employing a single writing step technique based on phase mask technology and KrF excimer laser irradiation. All waveguide Bragg gratings exhibit well-defined reflection [...] Read more.

Embedded channel waveguide Bragg gratings are fabricated in the Ormocer^® hybrid polymers OrmoComp^®, OrmoCore, and OrmoClad by employing a single writing step technique based on phase mask technology and KrF excimer laser irradiation. All waveguide Bragg gratings exhibit well-defined reflection peaks within the telecom wavelengths range with peak heights of up to 35 dB and −3 dB-bandwidths of down to 95 pm. Furthermore, the dependency of the fabricated embedded channel waveguide Bragg gratings on changes of the temperature and relative humidity are investigated. Here, we found that the Bragg grating in OrmoComp^® is significantly influenced by humidity variations, while the Bragg gratings in OrmoCore and OrmoClad exhibit linear and considerably high temperature sensitivities of up to −250 pm/

^{\circ}

C and a linear dependency on the relative humidity in the range of −9 pm/%. Full article

(This article belongs to the Special Issue Fiber Bragg Grating Based Sensors)

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16 pages, 6095 KiB

Open AccessArticle

BeiDou Geostationary Satellite Code Bias Modeling Using Fengyun-3C Onboard Measurements

by Kecai Jiang¹, Min Li^1,2,*, Qile Zhao^1,2,*, Wenwen Li¹ and Xiang Guo¹

¹ GNSS Research Center, Wuhan University, 129 Luoyu Road, Wuhan 430079, China

² Collaborative Innovation Center of Geospatial Technology, 129 Luoyu Road, Wuhan 430079, China

Sensors 2017, 17(11), 2460; https://doi.org/10.3390/s17112460 - 27 Oct 2017

Cited by 8 | Viewed by 5219

Abstract

This study validated and investigated elevation- and frequency-dependent systematic biases observed in ground-based code measurements of the Chinese BeiDou navigation satellite system, using the onboard BeiDou code measurement data from the Chinese meteorological satellite Fengyun-3C. Particularly for geostationary earth orbit satellites, sky-view coverage [...] Read more.

This study validated and investigated elevation- and frequency-dependent systematic biases observed in ground-based code measurements of the Chinese BeiDou navigation satellite system, using the onboard BeiDou code measurement data from the Chinese meteorological satellite Fengyun-3C. Particularly for geostationary earth orbit satellites, sky-view coverage can be achieved over the entire elevation and azimuth angle ranges with the available onboard tracking data, which is more favorable to modeling code biases. Apart from the BeiDou-satellite-induced biases, the onboard BeiDou code multipath effects also indicate pronounced near-field systematic biases that depend only on signal frequency and the line-of-sight directions. To correct these biases, we developed a proposed code correction model by estimating the BeiDou-satellite-induced biases as linear piece-wise functions in different satellite groups and the near-field systematic biases in a grid approach. To validate the code bias model, we carried out orbit determination using single-frequency BeiDou data with and without code bias corrections applied. Orbit precision statistics indicate that those code biases can seriously degrade single-frequency orbit determination. After the correction model was applied, the orbit position errors, 3D root mean square, were reduced from 150.6 to 56.3 cm. Full article

(This article belongs to the Section Remote Sensors)

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14 pages, 2050 KiB

Open AccessArticle

A Green Microbial Fuel Cell-Based Biosensor for In Situ Chromium (VI) Measurement in Electroplating Wastewater

by Li-Chun Wu¹, Teh-Hua Tsai², Man-Hai Liu³, Jui-Ling Kuo⁴, Yung-Chu Chang⁴ and Ying-Chien Chung^4,*

¹ Department of Logistics Engineering, Dongguan Polytechnic, Dongguan 523808, Guangdong, China

² Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei 10608, Taiwan

³ Department of Food Science, China University of Science and Technology, Taipei 11581, Taiwan

⁴ Department of Biological Science and Technology, China University of Science and Technology, Taipei 11581, Taiwan

Sensors 2017, 17(11), 2461; https://doi.org/10.3390/s17112461 - 27 Oct 2017

Cited by 38 | Viewed by 5768

Abstract

The extensive use of Cr(VI) in many industries and the disposal of Cr(VI)-containing wastes have resulted in Cr(VI)-induced environmental contamination. Cr(VI) compounds are associated with increased cancer risks; hence, the detection of toxic Cr(VI) compounds is crucial. Various methods have been developed for [...] Read more.

The extensive use of Cr(VI) in many industries and the disposal of Cr(VI)-containing wastes have resulted in Cr(VI)-induced environmental contamination. Cr(VI) compounds are associated with increased cancer risks; hence, the detection of toxic Cr(VI) compounds is crucial. Various methods have been developed for Cr(VI) measurement, but they are often conducted offsite and cannot provide real-time toxicity monitoring. A microbial fuel cell (MFC) is an eco-friendly and self-sustaining device that has great potential as a biosensor for in situ Cr(VI) measurement, especially for wastewater generated from different electroplating units. In this study, Exiguobacterium aestuarii YC211, a facultatively anaerobic, Cr(VI)-reducing, salt-tolerant, and exoelectrogenic bacterium, was isolated and inoculated into an MFC to evaluate its feasibility as a Cr(VI) biosensor. The Cr(VI) removal efficiency of E. aestuarii YC211 was not affected by the surrounding environment (pH 5–9, 20–35 °C, coexisting ions, and salinity of 0–15 g/L). The maximum power density of the MFC biosensor was 98.3 ± 1.5 mW/m² at 1500 Ω. A good linear relationship (r² = 0.997) was observed between the Cr(VI) concentration (2.5–60 mg/L) and the voltage output. The developed MFC biosensor is a simple device that can accurately measure Cr(VI) concentrations in the actual electroplating wastewater that is generated from different electroplating units within 30 min with low deviations (−6.1% to 2.2%). After treating the actual electroplating wastewater with the MFC, the predominant family in the biofilm was found to be Bacillaceae (95.3%) and was further identified as the originally inoculated E. aestuarii YC211 by next generation sequencing (NGS). Thus, the MFC biosensor can measure Cr(VI) concentrations in situ in the effluents from different electroplating units, and it can potentially help in preventing the violation of effluent regulations. Full article

(This article belongs to the Special Issue Environmental Monitoring Biosensors)

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22 pages, 5266 KiB

Open AccessArticle

Tightly-Coupled Integration of Multi-GNSS Single-Frequency RTK and MEMS-IMU for Enhanced Positioning Performance

by Tuan Li¹, Hongping Zhang^1,*, Xiaoji Niu¹ and Zhouzheng Gao^2,3

¹ GNSS Research Center, Wuhan University, 129 Luoyu Road, Wuhan 430079, China

² School of Land Science and Technology, China University of Geosciences, 29 Xueyuan Road, Beijing 100083, China

³ German Research Centre for Geosciences (GFZ), Telegrafenberg, 14473 Postsdam, Germany

Sensors 2017, 17(11), 2462; https://doi.org/10.3390/s17112462 - 27 Oct 2017

Cited by 65 | Viewed by 8573

Abstract

Dual-frequency Global Positioning System (GPS) Real-time Kinematics (RTK) has been proven in the past few years to be a reliable and efficient technique to obtain high accuracy positioning. However, there are still challenges for GPS single-frequency RTK, such as low reliability and ambiguity [...] Read more.

Dual-frequency Global Positioning System (GPS) Real-time Kinematics (RTK) has been proven in the past few years to be a reliable and efficient technique to obtain high accuracy positioning. However, there are still challenges for GPS single-frequency RTK, such as low reliability and ambiguity resolution (AR) success rate, especially in kinematic environments. Recently, multi-Global Navigation Satellite System (multi-GNSS) has been applied to enhance the RTK performance in terms of availability and reliability of AR. In order to further enhance the multi-GNSS single-frequency RTK performance in terms of reliability, continuity and accuracy, a low-cost micro-electro-mechanical system (MEMS) inertial measurement unit (IMU) is adopted in this contribution. We tightly integrate the single-frequency GPS/BeiDou/GLONASS and MEMS-IMU through the extended Kalman filter (EKF), which directly fuses the ambiguity-fixed double-differenced (DD) carrier phase observables and IMU data. A field vehicular test was carried out to evaluate the impacts of the multi-GNSS and IMU on the AR and positioning performance in different system configurations. Test results indicate that the empirical success rate of single-epoch AR for the tightly-coupled single-frequency multi-GNSS RTK/INS integration is over 99% even at an elevation cut-off angle of 40°, and the corresponding position time series is much more stable in comparison with the GPS solution. Besides, GNSS outage simulations show that continuous positioning with certain accuracy is possible due to the INS bridging capability when GNSS positioning is not available. Full article

(This article belongs to the Section Remote Sensors)

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16 pages, 7913 KiB

Open AccessArticle

Design of a Matching Network for a High-Sensitivity Broadband Magnetic Resonance Sounding Coil Sensor

by Yang Zhang^†, Fei Teng^†

, Suhang Li, Ling Wan and Tingting Lin^*

¹ College of Instrumentation & Electrical Engineering, Lab of Geo-Exploration Instrumentation of Ministry of Education, Jilin University, Changchun 130026, China

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2463; https://doi.org/10.3390/s17112463 - 27 Oct 2017

Cited by 9 | Viewed by 5260

Abstract

The magnetic resonance sounding (MRS) technique is a non-invasive geophysical method that can provide unique insights into the hydrological properties of groundwater. The Cu coil sensor is the preferred choice for detecting the weak MRS signal because of its high sensitivity, low fabrication [...] Read more.

The magnetic resonance sounding (MRS) technique is a non-invasive geophysical method that can provide unique insights into the hydrological properties of groundwater. The Cu coil sensor is the preferred choice for detecting the weak MRS signal because of its high sensitivity, low fabrication complexity and low cost. The tuned configuration was traditionally used for the MRS coil sensor design because of its high sensitivity and narrowband filtering. However, its narrow bandwidth may distort the MRS signals. To address this issue, a non-tuned design exhibiting a broad bandwidth has emerged recently, however, the sensitivity decreases as the bandwidth increases. Moreover, the effect of the MRS applications is often seriously influenced by power harmonic noises in the developed areas, especially low-frequency harmonics, resulting in saturation of the coil sensor, regardless of the tuned or non-tuned configuration. To solve the two aforementioned problems, we propose a matching network consisting of an LC broadband filter in parallel with a matching capacitor and provide a design for a coil sensor with a matching network (CSMN). The theoretical parameter calculations and the equivalent schematic of the CSMN with noise sources are investigated, and the sensitivity of the CSMN is evaluated by the Allan variance and the signal-to-noise ratio (SNR). Correspondingly, we constructed the CSMN with a 3 dB bandwidth, passband gain, normalized equivalent input noise and sensitivity (detection limit) of 1030 Hz, 4.6 dB, 1.78 nV/(Hz)^1/2 @ 2 kHz and 3 nV, respectively. Experimental tests in the laboratory show that the CSMN can not only improve the sensitivity, but also inhibit the signal distortion by suppressing power harmonic noises in the strong electromagnetic interference environment. Finally, a field experiment is performed with the CSMN to show a valid measurement of the signals of an MRS instrument system. Full article

(This article belongs to the Special Issue Magnetic Sensors and Their Applications)

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13 pages, 1529 KiB

Open AccessArticle

Electrochemical Detection of Plasma Immunoglobulin as a Biomarker for Alzheimer’s Disease

by Goulielmos-Zois Garyfallou¹, Orlando Ketebu¹, Samet Şahin^1,2, Elizabeta B. Mukaetova-Ladinska³, Michael Catt⁴ and Eileen Hao Yu^1,*

¹ School of Chemical Engineering and Advance Materials, Newcastle University, Newcastle upon Tyne NE1 7RU, UK

² Department of Chemical and Process Engineering, Faculty of Engineering, Bilecik Şeyh Edebali University, 11230 Bilecik, Turkey

³ Department of Neuroscience, Psychology and Behaviour, University of Leicester, University Road, Leicester LE1 7RH, UK

⁴ Institute of Neuroscience, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK

Sensors 2017, 17(11), 2464; https://doi.org/10.3390/s17112464 - 27 Oct 2017

Cited by 26 | Viewed by 6523

Abstract

The clinical diagnosis and treatment of Alzheimer’s disease (AD) represent a challenge to clinicians due to the variability of clinical symptomatology as well as the unavailability of reliable diagnostic tests. In this study, the development of a novel electrochemical assay and its potential [...] Read more.

The clinical diagnosis and treatment of Alzheimer’s disease (AD) represent a challenge to clinicians due to the variability of clinical symptomatology as well as the unavailability of reliable diagnostic tests. In this study, the development of a novel electrochemical assay and its potential to detect peripheral blood biomarkers to diagnose AD using plasma immunoglobulins is investigated. The immunosensor employs a gold electrode as the immobilizing substrate, albumin depleted plasma immunoglobulin as the biomarker, and polyclonal rabbit Anti-human immunoglobulin (against IgA, IgG, IgM) as the receptor for plasma conjugation. The assay showed good response, sensitivity and reproducibility in differentiating plasma immunoglobulin from AD and control subjects down to 10⁻⁹ dilutions of plasma immunoglobulin representing plasma content concentrations in the pg mL⁻¹ range. The newly developed assay is highly sensitive, less time consuming, easy to handle, can be easily modified to detect other dementia-related biomarkers in blood samples, and can be easily integrated into portable devices. Full article

(This article belongs to the Section Biosensors)

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10 pages, 1719 KiB

Open AccessArticle

Determination of Fluid Density and Viscosity by Analyzing Flexural Wave Propagations on the Vibrating Micro-Cantilever

by Deokman Kim^1,†, Seongkyeol Hong^2,†, Jaesung Jang^2,*

and Junhong Park^1,*

¹ Department of Mechanical Engineering, Hanyang University, Seoul 04763, Korea

² Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea

^† These two authors contributed equally to this work.

Sensors 2017, 17(11), 2466; https://doi.org/10.3390/s17112466 - 27 Oct 2017

Cited by 19 | Viewed by 4791

Abstract

The determination of fluid density and viscosity using most cantilever-based sensors is based on changes in resonant frequency and peak width. Here, we present a wave propagation analysis using piezoelectrically excited micro-cantilevers under distributed fluid loading. The standing wave shapes of microscale-thickness cantilevers [...] Read more.

The determination of fluid density and viscosity using most cantilever-based sensors is based on changes in resonant frequency and peak width. Here, we present a wave propagation analysis using piezoelectrically excited micro-cantilevers under distributed fluid loading. The standing wave shapes of microscale-thickness cantilevers partially immersed in liquids (water, 25% glycerol, and acetone), and nanoscale-thickness microfabricated cantilevers fully immersed in gases (air at three different pressures, carbon dioxide, and nitrogen) were investigated to identify the effects of fluid-structure interactions to thus determine the fluid properties. This measurement method was validated by comparing with the known fluid properties, which agreed well with the measurements. The relative differences for the liquids were less than 4.8% for the densities and 3.1% for the viscosities, and those for the gases were less than 6.7% for the densities and 7.3% for the viscosities, showing better agreements in liquids than in gases. Full article

(This article belongs to the Section Physical Sensors)

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12 pages, 5684 KiB

Open AccessArticle

Monitoring of Pre-Load on Rock Bolt Using Piezoceramic-Transducer Enabled Time Reversal Method

by Linsheng Huo¹

, Bo Wang^2,*,†, Dongdong Chen¹ and Gangbing Song^3,*

¹ State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China

² Key Laboratory of Transportation Tunnel Engineering, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, Sichuan, China

³ Smart Material and Structure Laboratory, Department of Mechanical Engineering, University of Houston, Houston, TX 77204, USA

^† The co-first author due to his equal contribution with the first author.

Sensors 2017, 17(11), 2467; https://doi.org/10.3390/s17112467 - 27 Oct 2017

Cited by 36 | Viewed by 5964

Abstract

Rock bolts ensure structural stability for tunnels and many other underground structures. The pre-load on a rock bolt plays an important role in the structural reinforcement and it is vital to monitor the pre-load status of rock bolts. In this paper, a rock [...] Read more.

Rock bolts ensure structural stability for tunnels and many other underground structures. The pre-load on a rock bolt plays an important role in the structural reinforcement and it is vital to monitor the pre-load status of rock bolts. In this paper, a rock bolt pre-load monitoring method based on the piezoceramic enabled time reversal method is proposed. A lead zirconate titanate (PZT) patch transducer, which works as an actuator to generate stress waves, is bonded onto the anchor plate of the rock bolt. A smart washer, which is fabricated by sandwiching a PZT patch between two metal rings, is installed between the hex nut and the anchor plate along the rock bolt. The smart washer functions as a sensor to detect the stress wave. With the increase of the pre-load values on the rock bolt, the effective contact surface area between the smart washer and the anchor plate, benefiting the stress wave propagation crossing the contact surface. With the help of time reversal technique, experimental results reveal that the magnitude of focused signal clearly increases with the increase of the pre-load on a rock bolt before the saturation which happens beyond a relatively high value of the pre-load. The proposed method provides an innovative and real time means to monitor the pre-load level of a rock bolt. By employing this method, the pre-load degradation process on a rock bolt can be clearly monitored. Please note that, currently, the proposed method applies to only new rock bolts, on which it is possible to install the PZT smart washer. Full article

(This article belongs to the Section Physical Sensors)

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21 pages, 633 KiB

Open AccessArticle

Trail-Based Search for Efficient Event Report to Mobile Actors in Wireless Sensor and Actor Networks

by Zhezhuang Xu^1,*, Guanglun Liu¹, Haotian Yan², Bin Cheng³ and Feilong Lin⁴

¹ School of Electrical Engineering and Automation, Fuzhou University, Fuzhou 350116, China

² Department of Electronic and Information Engineering, Hong Kong Polytechnic University, Hong Kong 999077, China

³ Wireless Information Network Laboratory (WINLAB), Rutgers University, North Brunswick, NJ 08902, USA

⁴ College of Mathematics, Physics and Information Engineering, Zhejiang Normal University, Jinhua 321004, China

Sensors 2017, 17(11), 2468; https://doi.org/10.3390/s17112468 - 27 Oct 2017

Cited by 5 | Viewed by 3451

Abstract

In wireless sensor and actor networks, when an event is detected, the sensor node needs to transmit an event report to inform the actor. Since the actor moves in the network to execute missions, its location is always unavailable to the sensor nodes. [...] Read more.

In wireless sensor and actor networks, when an event is detected, the sensor node needs to transmit an event report to inform the actor. Since the actor moves in the network to execute missions, its location is always unavailable to the sensor nodes. A popular solution is the search strategy that can forward the data to a node without its location information. However, most existing works have not considered the mobility of the node, and thus generate significant energy consumption or transmission delay. In this paper, we propose the trail-based search (TS) strategy that takes advantage of actor’s mobility to improve the search efficiency. The main idea of TS is that, when the actor moves in the network, it can leave its trail composed of continuous footprints. The search packet with the event report is transmitted in the network to search the actor or its footprints. Once an effective footprint is discovered, the packet will be forwarded along the trail until it is received by the actor. Moreover, we derive the condition to guarantee the trail connectivity, and propose the redundancy reduction scheme based on TS (TS-R) to reduce nontrivial transmission redundancy that is generated by the trail. The theoretical and numerical analysis is provided to prove the efficiency of TS. Compared with the well-known expanding ring search (ERS), TS significantly reduces the energy consumption and search delay. Full article

(This article belongs to the Section Sensor Networks)

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19 pages, 30479 KiB

Open AccessArticle

Inverse Source Data-Processing Strategies for Radio-Frequency Localization in Indoor Environments

by Gianluca Gennarelli^1,*, Obada Al Khatib² and Francesco Soldovieri¹

¹ Institute for Electromagnetic Sensing of the Environment, National Research Council of Italy, Via Diocleziano 328, Napoli 80124, Italy

² Faculty of Engineering and Information Sciences, University ofWollongong in Dubai, Block 15, Dubai Knowledge Park, 20183 Dubai, UAE

Sensors 2017, 17(11), 2469; https://doi.org/10.3390/s17112469 - 27 Oct 2017

Cited by 7 | Viewed by 4129

Abstract

Indoor positioning of mobile devices plays a key role in many aspects of our daily life. These include real-time people tracking and monitoring, activity recognition, emergency detection, navigation, and numerous location based services. Despite many wireless technologies and data-processing algorithms have been developed [...] Read more.

Indoor positioning of mobile devices plays a key role in many aspects of our daily life. These include real-time people tracking and monitoring, activity recognition, emergency detection, navigation, and numerous location based services. Despite many wireless technologies and data-processing algorithms have been developed in recent years, indoor positioning is still a problem subject of intensive research. This paper deals with the active radio-frequency (RF) source localization in indoor scenarios. The localization task is carried out at the physical layer thanks to receiving sensor arrays which are deployed on the border of the surveillance region to record the signal emitted by the source. The localization problem is formulated as an imaging one by taking advantage of the inverse source approach. Different measurement configurations and data-processing/fusion strategies are examined to investigate their effectiveness in terms of localization accuracy under both line-of-sight (LOS) and non-line of sight (NLOS) conditions. Numerical results based on full-wave synthetic data are reported to support the analysis. Full article

(This article belongs to the Section Physical Sensors)

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13 pages, 2378 KiB

Open AccessArticle

Fast Detection of Striped Stem-Borer (Chilo suppressalis Walker) Infested Rice Seedling Based on Visible/Near-Infrared Hyperspectral Imaging System

by Yangyang Fan^1,2, Tao Wang^1,2, Zhengjun Qiu^1,2,*, Jiyu Peng^1,2

, Chu Zhang^1,2,*

and Yong He^1,2

¹ College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China

² Key Laboratory of Spectroscopy Sensing, Ministry of Agriculture, Hangzhou 310058, China

Sensors 2017, 17(11), 2470; https://doi.org/10.3390/s17112470 - 27 Oct 2017

Cited by 42 | Viewed by 8237

Abstract

Striped stem-borer (SSB) infestation is one of the most serious sources of damage to rice growth. A rapid and non-destructive method of early SSB detection is essential for rice-growth protection. In this study, hyperspectral imaging combined with chemometrics was used to detect early [...] Read more.

Striped stem-borer (SSB) infestation is one of the most serious sources of damage to rice growth. A rapid and non-destructive method of early SSB detection is essential for rice-growth protection. In this study, hyperspectral imaging combined with chemometrics was used to detect early SSB infestation in rice and identify the degree of infestation (DI). Visible/near-infrared hyperspectral images (in the spectral range of 380 nm to 1030 nm) were taken of the healthy rice plants and infested rice plants by SSB for 2, 4, 6, 8 and 10 days. A total of 17 characteristic wavelengths were selected from the spectral data extracted from the hyperspectral images by the successive projection algorithm (SPA). Principal component analysis (PCA) was applied to the hyperspectral images, and 16 textural features based on the gray-level co-occurrence matrix (GLCM) were extracted from the first two principal component (PC) images. A back-propagation neural network (BPNN) was used to establish infestation degree evaluation models based on full spectra, characteristic wavelengths, textural features and features fusion, respectively. BPNN models based on a fusion of characteristic wavelengths and textural features achieved the best performance, with classification accuracy of calibration and prediction sets over 95%. The accuracy of each infestation degree was satisfactory, and the accuracy of rice samples infested for 2 days was slightly low. In all, this study indicated the feasibility of hyperspectral imaging techniques to detect early SSB infestation and identify degrees of infestation. Full article

(This article belongs to the Special Issue Sensors in Agriculture)

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8 pages, 2153 KiB

Open AccessArticle

A New Scale Factor Adjustment Method for Magnetic Force Feedback Accelerometer

by Xiangqing Huang¹, Zhongguang Deng¹, Yafei Xie¹, Zhu Li², Ji Fan^1,3 and Liangcheng Tu^1,2,3,*

¹ MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics, School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China

² School of Physics and Astronomy, Sun Yat-sen University, Guangzhou 510275, China

³ Institute of Geophysics, Huazhong University of Science and Technology, Wuhan 430074, China

Sensors 2017, 17(11), 2471; https://doi.org/10.3390/s17112471 - 27 Oct 2017

Cited by 15 | Viewed by 6106

Abstract

A new and simple method to adjust the scale factor of a magnetic force feedback accelerometer is presented, which could be used in developing a rotating accelerometer gravity gradient instrument (GGI). Adjusting and matching the acceleration-to-current transfer function of the four accelerometers automatically [...] Read more.

A new and simple method to adjust the scale factor of a magnetic force feedback accelerometer is presented, which could be used in developing a rotating accelerometer gravity gradient instrument (GGI). Adjusting and matching the acceleration-to-current transfer function of the four accelerometers automatically is one of the basic and necessary technologies for rejecting the common mode accelerations in the development of GGI. In order to adjust the scale factor of the magnetic force rebalance accelerometer, an external current is injected and combined with the normal feedback current; they are then applied together to the torque coil of the magnetic actuator. The injected current could be varied proportionally according to the external adjustment needs, and the change in the acceleration-to-current transfer function then realized dynamically. The new adjustment method has the advantages of no extra assembly and ease of operation. Changes in the scale factors range from 33% smaller to 100% larger are verified experimentally by adjusting the different external coefficients. The static noise of the used accelerometer is compared under conditions with and without the injecting current, and the experimental results find no change at the current noise level, which further confirms the validity of the presented method. Full article

(This article belongs to the Special Issue Inertial Sensors for Positioning and Navigation)

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24 pages, 5808 KiB

Open AccessArticle

DEEP-SEE: Joint Object Detection, Tracking and Recognition with Application to Visually Impaired Navigational Assistance

by Ruxandra Tapu^1,2,*,†, Bogdan Mocanu^1,2,† and Titus Zaharia¹

¹ Advanced Research and TEchniques for Multidimensional Imaging Systems Department, Institut Mines-Télécom/Télécom SudParis, UMR CNRS MAP5 8145 and 5157 SAMOVAR, 9 rue Charles Fourier, 91000 Évry, France

² Telecommunication Department, Faculty of ETTI, University “Politehnica” of Bucharest, SplaiulIndependentei 313, 060042 Bucharest, Romania

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2473; https://doi.org/10.3390/s17112473 - 28 Oct 2017

Cited by 70 | Viewed by 9968

Abstract

In this paper, we introduce the so-called DEEP-SEE framework that jointly exploits computer vision algorithms and deep convolutional neural networks (CNNs) to detect, track and recognize in real time objects encountered during navigation in the outdoor environment. A first feature concerns an object [...] Read more.

In this paper, we introduce the so-called DEEP-SEE framework that jointly exploits computer vision algorithms and deep convolutional neural networks (CNNs) to detect, track and recognize in real time objects encountered during navigation in the outdoor environment. A first feature concerns an object detection technique designed to localize both static and dynamic objects without any a priori knowledge about their position, type or shape. The methodological core of the proposed approach relies on a novel object tracking method based on two convolutional neural networks trained offline. The key principle consists of alternating between tracking using motion information and predicting the object location in time based on visual similarity. The validation of the tracking technique is performed on standard benchmark VOT datasets, and shows that the proposed approach returns state-of-the-art results while minimizing the computational complexity. Then, the DEEP-SEE framework is integrated into a novel assistive device, designed to improve cognition of VI people and to increase their safety when navigating in crowded urban scenes. The validation of our assistive device is performed on a video dataset with 30 elements acquired with the help of VI users. The proposed system shows high accuracy (>90%) and robustness (>90%) scores regardless on the scene dynamics. Full article

(This article belongs to the Special Issue Video Analysis and Tracking Using State-of-the-Art Sensors)

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10 pages, 4560 KiB

Open AccessArticle

An Electronic System for the Contactless Reading of ECG Signals

by Francesca Romana Parente¹

, Marco Santonico², Alessandro Zompanti², Mario Benassai³, Giuseppe Ferri¹

, Arnaldo D’Amico⁴ and Giorgio Pennazza^2,*

¹ Department of Industrial and Information Engineering and Economics, University of L’Aquila, 67100 L’Aquila, Italy

² Unit of Electronics for Sensor Systems, Department of Engineering Campus Bio-Medico University of Rome, 00128 Rome, Italy

³ ALTEC S.p.A., Aerospace Logistics and Technology Engineering Company, 10146 Torino, Italy

⁴ Department of Electronic Engineering, University of Rome Tor Vergata, 00133 Rome, Italy

Sensors 2017, 17(11), 2474; https://doi.org/10.3390/s17112474 - 28 Oct 2017

Cited by 25 | Viewed by 7195

Abstract

The aim of this work is the development of a contactless capacitive sensory system for the detection of (Electrocardiographic) ECG-like signals. The acquisition approach is based on a capacitive coupling with the patient body performed by electrodes integrated in a front-end circuit. The [...] Read more.

The aim of this work is the development of a contactless capacitive sensory system for the detection of (Electrocardiographic) ECG-like signals. The acquisition approach is based on a capacitive coupling with the patient body performed by electrodes integrated in a front-end circuit. The proposed system is able to detect changes in the electric charge related to the heart activity. Due to the target signal weakness and to the presence of other undesired signals, suitable amplification stages and analogue filters are required. Simulated results allowed us to evaluate the effectiveness of the approach, whereas experimental measurements, recorded without contact to the skin, have validated the practical effectiveness of the proposed architecture. The system operates with a supply voltage of ±9 V with an overall power consumption of about 10 mW. The analogue output of the electronic interface is connected to an ATmega328 microcontroller implementing the A/D conversion and the data acquisition. The collected data can be displayed on any multimedia support for real-time tracking applications. Full article

(This article belongs to the Special Issue Sensors for Health Monitoring and Disease Diagnosis)

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29 pages, 13934 KiB

Open AccessArticle

Road Lane Detection Robust to Shadows Based on a Fuzzy System Using a Visible Light Camera Sensor

by Toan Minh Hoang, Na Rae Baek, Se Woon Cho, Ki Wan Kim and Kang Ryoung Park^*

Division of Electronics and Electrical Engineering, Dongguk University, 30 Pildong-ro 1-gil, Jung-gu, Seoul 100-715, Korea

Sensors 2017, 17(11), 2475; https://doi.org/10.3390/s17112475 - 28 Oct 2017

Cited by 43 | Viewed by 9878

Abstract

Recently, autonomous vehicles, particularly self-driving cars, have received significant attention owing to rapid advancements in sensor and computation technologies. In addition to traffic sign recognition, road lane detection is one of the most important factors used in lane departure warning systems and autonomous [...] Read more.

Recently, autonomous vehicles, particularly self-driving cars, have received significant attention owing to rapid advancements in sensor and computation technologies. In addition to traffic sign recognition, road lane detection is one of the most important factors used in lane departure warning systems and autonomous vehicles for maintaining the safety of semi-autonomous and fully autonomous systems. Unlike traffic signs, road lanes are easily damaged by both internal and external factors such as road quality, occlusion (traffic on the road), weather conditions, and illumination (shadows from objects such as cars, trees, and buildings). Obtaining clear road lane markings for recognition processing is a difficult challenge. Therefore, we propose a method to overcome various illumination problems, particularly severe shadows, by using fuzzy system and line segment detector algorithms to obtain better results for detecting road lanes by a visible light camera sensor. Experimental results from three open databases, Caltech dataset, Santiago Lanes dataset (SLD), and Road Marking dataset, showed that our method outperformed conventional lane detection methods. Full article

(This article belongs to the Special Issue Mechatronic Systems for Automatic Vehicles)

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13 pages, 4682 KiB

Open AccessArticle

Indoor Air Quality Analysis Using Deep Learning with Sensor Data

by Jaehyun Ahn¹, Dongil Shin², Kyuho Kim² and Jihoon Yang^2,*

¹ Data Labs, Buzzni, Seoul 08788, Korea

² Department of Computer Science and Engineering, Sogang University, Seoul 04107, Korea

Sensors 2017, 17(11), 2476; https://doi.org/10.3390/s17112476 - 28 Oct 2017

Cited by 95 | Viewed by 16167

Abstract

Indoor air quality analysis is of interest to understand the abnormal atmospheric phenomena and external factors that affect air quality. By recording and analyzing quality measurements, we are able to observe patterns in the measurements and predict the air quality of near future. [...] Read more.

Indoor air quality analysis is of interest to understand the abnormal atmospheric phenomena and external factors that affect air quality. By recording and analyzing quality measurements, we are able to observe patterns in the measurements and predict the air quality of near future. We designed a microchip made out of sensors that is capable of periodically recording measurements, and proposed a model that estimates atmospheric changes using deep learning. In addition, we developed an efficient algorithm to determine the optimal observation period for accurate air quality prediction. Experimental results with real-world data demonstrate the feasibility of our approach. Full article

(This article belongs to the Special Issue Air Pollution Sensors: A New Class of Tools to Measure Air Quality)

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16 pages, 23060 KiB

Open AccessArticle

Fault Detection of Bearing Systems through EEMD and Optimization Algorithm

by Dong-Han Lee, Jong-Hyo Ahn and Bong-Hwan Koh^*

Department of Mechanical, Robotics and Energy Engineering, Dongguk University-Seoul, 30 Pildong-ro 1 gil, Jung-gu, Seoul 100-715, Korea

Sensors 2017, 17(11), 2477; https://doi.org/10.3390/s17112477 - 28 Oct 2017

Cited by 43 | Viewed by 5239

Abstract

This study proposes a fault detection and diagnosis method for bearing systems using ensemble empirical mode decomposition (EEMD) based feature extraction, in conjunction with particle swarm optimization (PSO), principal component analysis (PCA), and Isomap. First, a mathematical model is assumed to generate vibration [...] Read more.

This study proposes a fault detection and diagnosis method for bearing systems using ensemble empirical mode decomposition (EEMD) based feature extraction, in conjunction with particle swarm optimization (PSO), principal component analysis (PCA), and Isomap. First, a mathematical model is assumed to generate vibration signals from damaged bearing components, such as the inner-race, outer-race, and rolling elements. The process of decomposing vibration signals into intrinsic mode functions (IMFs) and extracting statistical features is introduced to develop a damage-sensitive parameter vector. Finally, PCA and Isomap algorithm are used to classify and visualize this parameter vector, to separate damage characteristics from healthy bearing components. Moreover, the PSO-based optimization algorithm improves the classification performance by selecting proper weightings for the parameter vector, to maximize the visualization effect of separating and grouping of parameter vectors in three-dimensional space. Full article

(This article belongs to the Section Physical Sensors)

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22 pages, 6797 KiB

Open AccessArticle

Distributed Channel Allocation and Time Slot Optimization for Green Internet of Things

by Kaiqi Ding¹, Haitao Zhao^1,*

, Xiping Hu^2,3,* and Jibo Wei¹

¹ College of Electronic Science, National University of Defense Technology, Changsha, 410073, China

² Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China

³ Department of Mechanical and Automation Engineering, Chinese University of Hong Kong, Hong Kong

Sensors 2017, 17(11), 2479; https://doi.org/10.3390/s17112479 - 28 Oct 2017

Cited by 8 | Viewed by 5111

Abstract

In sustainable smart cities, power saving is a severe challenge in the energy-constrained Internet of Things (IoT). Efficient utilization of limited multiple non-overlap channels and time resources is a promising solution to reduce the network interference and save energy consumption. In this paper, [...] Read more.

In sustainable smart cities, power saving is a severe challenge in the energy-constrained Internet of Things (IoT). Efficient utilization of limited multiple non-overlap channels and time resources is a promising solution to reduce the network interference and save energy consumption. In this paper, we propose a joint channel allocation and time slot optimization solution for IoT. First, we propose a channel ranking algorithm which enables each node to rank its available channels based on the channel properties. Then, we propose a distributed channel allocation algorithm so that each node can choose a proper channel based on the channel ranking and its own residual energy. Finally, the sleeping duration and spectrum sensing duration are jointly optimized to maximize the normalized throughput and satisfy energy consumption constraints simultaneously. Different from the former approaches, our proposed solution requires no central coordination or any global information that each node can operate based on its own local information in a total distributed manner. Also, theoretical analysis and extensive simulations have validated that when applying our solution in the network of IoT: (i) each node can be allocated to a proper channel based on the residual energy to balance the lifetime; (ii) the network can rapidly converge to a collision-free transmission through each node’s learning ability in the process of the distributed channel allocation; and (iii) the network throughput is further improved via the dynamic time slot optimization. Full article

(This article belongs to the Special Issue Advances in Sensors for Sustainable Smart Cities and Smart Buildings)

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16 pages, 5176 KiB

Open AccessArticle

An Adaptive Transmitting Scheme for Interrupted Sampling Repeater Jamming Suppression

by Chao Zhou^1,2, Feifeng Liu^1,2,* and Quanhua Liu^1,2

¹ Radar Research Laboratory, School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China

² Key Laboratory of Electronic and Information Technology in Satellite Navigation (Beijing Institute of Technology), Ministry of Education, Beijing 100081, China

Sensors 2017, 17(11), 2480; https://doi.org/10.3390/s17112480 - 29 Oct 2017

Cited by 72 | Viewed by 5295

Abstract

The interrupted sampling repeater jamming (ISRJ) based on a digital radio frequency memory (DRFM) device is a new type of coherent jamming. This kind of jamming usually occurs as main-lobe jamming and has the advantages of low power requirements and easy parameter adjustment, [...] Read more.

The interrupted sampling repeater jamming (ISRJ) based on a digital radio frequency memory (DRFM) device is a new type of coherent jamming. This kind of jamming usually occurs as main-lobe jamming and has the advantages of low power requirements and easy parameter adjustment, posing a serious threat to the modern radar systems. In order to suppress the ISRJ, this paper proposes an adaptive transmitting scheme based on a phase-coded signal. The scheme firstly performs jamming perception to estimate the jamming parameters, then, on this basis, optimizes the waveform with genetic algorithm. With the optimized waveform, the jamming signal is orthogonal to the target echo, thus it can be easily suppressed with pulse compression. Simulation experiments are performed to verify the effectiveness of the scheme and the results suggest that the peak-to-side-lobe ratio (PSR) and integrated side-lobe level (ISL) of the pulse compression can be improved by about 16 dB and 15 dB, respectively, for the case where the jamming-to-signal ratio (JSR) is 13 dB. Full article

(This article belongs to the Section Remote Sensors)

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19 pages, 6188 KiB

Open AccessArticle

Electrical and Self-Sensing Properties of Ultra-High-Performance Fiber-Reinforced Concrete with Carbon Nanotubes

by Ilhwan You¹, Doo-Yeol Yoo^2,*, Soonho Kim², Min-Jae Kim² and Goangseup Zi¹

¹ School of Civil, Environmental and Architectural Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Korea

² Department of Architectural Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea

Sensors 2017, 17(11), 2481; https://doi.org/10.3390/s17112481 - 29 Oct 2017

Cited by 116 | Viewed by 9860

Abstract

This study examined the electrical and self-sensing capacities of ultra-high-performance fiber-reinforced concrete (UHPFRC) with and without carbon nanotubes (CNTs). For this, the effects of steel fiber content, orientation, and pore water content on the electrical and piezoresistive properties of UHPFRC without CNTs were [...] Read more.

This study examined the electrical and self-sensing capacities of ultra-high-performance fiber-reinforced concrete (UHPFRC) with and without carbon nanotubes (CNTs). For this, the effects of steel fiber content, orientation, and pore water content on the electrical and piezoresistive properties of UHPFRC without CNTs were first evaluated. Then, the effect of CNT content on the self-sensing capacities of UHPFRC under compression and flexure was investigated. Test results indicated that higher steel fiber content, better fiber orientation, and higher amount of pore water led to higher electrical conductivity of UHPFRC. The effects of fiber orientation and drying condition on the electrical conductivity became minor as sufficiently high amount of steel fibers, 3% by volume, was added. Including only steel fibers did not impart UHPFRC with piezoresistive properties. Addition of CNTs substantially improved the electrical conductivity of UHPFRC. Under compression, UHPFRC with a CNT content of 0.3% or greater had a self-sensing ability that was activated by the formation of cracks, and better sensing capacity was achieved by including greater amount of CNTs. Furthermore, the pre-peak flexural behavior of UHPFRC was precisely simulated with a fractional change in resistivity when 0.3% CNTs were incorporated. The pre-cracking self-sensing capacity of UHPFRC with CNTs was more effective under tensile stress state than under compressive stress state. Full article

(This article belongs to the Section Physical Sensors)

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26 pages, 8373 KiB

Open AccessArticle

Motion-Blur-Free High-Speed Video Shooting Using a Resonant Mirror

by Michiaki Inoue¹, Qingyi Gu², Mingjun Jiang¹

, Takeshi Takaki¹, Idaku Ishii^1,* and Kenji Tajima³

¹ Department of System Cybernetics, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan

² Institute of Automation, Chinese Academy of Sciences, No. 95 Zhongguancun East Road, Haidian District, Beijing 100190, China

³ Photron Ltd., Kanda Jinbo-cho 1-105, Chiyoda-Ku, Tokyo 101-0051, Japan

Sensors 2017, 17(11), 2483; https://doi.org/10.3390/s17112483 - 29 Oct 2017

Cited by 10 | Viewed by 7505

Abstract

This study proposes a novel concept of actuator-driven frame-by-frame intermittent tracking for motion-blur-free video shooting of fast-moving objects. The camera frame and shutter timings are controlled for motion blur reduction in synchronization with a free-vibration-type actuator vibrating with a large amplitude at hundreds [...] Read more.

This study proposes a novel concept of actuator-driven frame-by-frame intermittent tracking for motion-blur-free video shooting of fast-moving objects. The camera frame and shutter timings are controlled for motion blur reduction in synchronization with a free-vibration-type actuator vibrating with a large amplitude at hundreds of hertz so that motion blur can be significantly reduced in free-viewpoint high-frame-rate video shooting for fast-moving objects by deriving the maximum performance of the actuator. We develop a prototype of a motion-blur-free video shooting system by implementing our frame-by-frame intermittent tracking algorithm on a high-speed video camera system with a resonant mirror vibrating at 750 Hz. It can capture 1024 × 1024 images of fast-moving objects at 750 fps with an exposure time of 0.33 ms without motion blur. Several experimental results for fast-moving objects verify that our proposed method can reduce image degradation from motion blur without decreasing the camera exposure time. Full article

(This article belongs to the Special Issue Video Analysis and Tracking Using State-of-the-Art Sensors)

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23 pages, 3393 KiB

Open AccessArticle

Model-Based Localization and Tracking Using Bluetooth Low-Energy Beacons

by F. Serhan Daniş^1,2,*

and Ali Taylan Cemgil¹

¹ Department of Computer Engineering, Boğaziçi University, Istanbul 34342, Turkey

² Department of Computer Engineering, Galatasaray University, Istanbul 34349, Turkey

Sensors 2017, 17(11), 2484; https://doi.org/10.3390/s17112484 - 29 Oct 2017

Cited by 81 | Viewed by 9388

Abstract

We introduce a high precision localization and tracking method that makes use of cheap Bluetooth low-energy (BLE) beacons only. We track the position of a moving sensor by integrating highly unreliable and noisy BLE observations streaming from multiple locations. A novel aspect of [...] Read more.

We introduce a high precision localization and tracking method that makes use of cheap Bluetooth low-energy (BLE) beacons only. We track the position of a moving sensor by integrating highly unreliable and noisy BLE observations streaming from multiple locations. A novel aspect of our approach is the development of an observation model, specifically tailored for received signal strength indicator (RSSI) fingerprints: a combination based on the optimal transport model of Wasserstein distance. The tracking results of the entire system are compared with alternative baseline estimation methods, such as nearest neighboring fingerprints and an artificial neural network. Our results show that highly accurate estimation from noisy Bluetooth data is practically feasible with an observation model based on Wasserstein distance interpolation combined with the sequential Monte Carlo (SMC) method for tracking. Full article

(This article belongs to the Special Issue Sensors and Sensing in Indoor Localization, Tracking, Navigation and Activity Monitoring)

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26 pages, 18693 KiB

Open AccessArticle

Development of a Shipboard Remote Control and Telemetry Experimental System for Large-Scale Model’s Motions and Loads Measurement in Realistic Sea Waves

by Jialong Jiao¹

, Huilong Ren², Christiaan Adika Adenya³

and Chaohe Chen^1,*

¹ School of Civil Engineering and Transportation, South China University of Technology, Guangzhou, China

² College of Shipbuilding Engineering, Harbin Engineering University, Harbin 150001, China

³ Department of Marine Engineering and Maritime Operations, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000–00200 Nairobi, Kenya

Sensors 2017, 17(11), 2485; https://doi.org/10.3390/s17112485 - 29 Oct 2017

Cited by 9 | Viewed by 7159

Abstract

Wave-induced motion and load responses are important criteria for ship performance evaluation. Physical experiments have long been an indispensable tool in the predictions of ship’s navigation state, speed, motions, accelerations, sectional loads and wave impact pressure. Currently, majority of the experiments are conducted [...] Read more.

Wave-induced motion and load responses are important criteria for ship performance evaluation. Physical experiments have long been an indispensable tool in the predictions of ship’s navigation state, speed, motions, accelerations, sectional loads and wave impact pressure. Currently, majority of the experiments are conducted in laboratory tank environment, where the wave environments are different from the realistic sea waves. In this paper, a laboratory tank testing system for ship motions and loads measurement is reviewed and reported first. Then, a novel large-scale model measurement technique is developed based on the laboratory testing foundations to obtain accurate motion and load responses of ships in realistic sea conditions. For this purpose, a suite of advanced remote control and telemetry experimental system was developed in-house to allow for the implementation of large-scale model seakeeping measurement at sea. The experimental system includes a series of technique sensors, e.g., the Global Position System/Inertial Navigation System (GPS/INS) module, course top, optical fiber sensors, strain gauges, pressure sensors and accelerometers. The developed measurement system was tested by field experiments in coastal seas, which indicates that the proposed large-scale model testing scheme is capable and feasible. Meaningful data including ocean environment parameters, ship navigation state, motions and loads were obtained through the sea trial campaign. Full article

(This article belongs to the Special Issue Smart Sensors for Mechatronic and Robotic Systems)

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13 pages, 5856 KiB

Open AccessArticle

A Laboratory Experimental Study: An FBG-PVC Tube Integrated Device for Monitoring the Slip Surface of Landslides

by Kai Wang^1,2

, Shaojie Zhang^1,*, Jiang Chen³, Pengxiao Teng⁴, Fangqiang Wei⁵ and Qiao Chen⁵

¹ Key Laboratory of Mountain Hazards and Earth Surface Process, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China

² University of Chinese Academy of Sciences, Beijing 100049, China

³ College of Architecture & Environment, Sichuan University, Chengdu 610065, China

⁴ Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China

⁵ Chongqing Institute of green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China

Sensors 2017, 17(11), 2486; https://doi.org/10.3390/s17112486 - 30 Oct 2017

Cited by 15 | Viewed by 5223

Abstract

A new detection device was designed by integrating fiber Bragg grating (FBG) and polyvinyl chloride (PVC) tube in order to monitor the slip surface of a landslide. Using this new FBG-based device, a corresponding slope model with a pre-set slip surface was designed, [...] Read more.

A new detection device was designed by integrating fiber Bragg grating (FBG) and polyvinyl chloride (PVC) tube in order to monitor the slip surface of a landslide. Using this new FBG-based device, a corresponding slope model with a pre-set slip surface was designed, and seven tests with different soil properties were carried out in laboratory conditions. The FBG sensing fibers were fixed on the PVC tube to measure strain distributions of PVC tube at different elevation. Test results indicated that the PVC tube could keep deformation compatible with soil mass. The new device was able to monitor slip surface location before sliding occurrence, and the location of monitored slip surface was about 1–2 cm above the pre-set slip surface, which basically agreed with presupposition results. The monitoring results are expected to be used to pre-estimate landslide volume and provide a beneficial option for evaluating the potential impact of landslides on shipping safety in the Three Gorges area. Full article

(This article belongs to the Special Issue Fiber Bragg Grating Based Sensors)

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22 pages, 11692 KiB

Open AccessArticle

Village Building Identification Based on Ensemble Convolutional Neural Networks

by Zhiling Guo¹, Qi Chen^1,2,†, Guangming Wu^1,†

, Yongwei Xu¹, Ryosuke Shibasaki¹ and Xiaowei Shao^1,*

¹ Center for Spatial Information Science, University of Tokyo, Kashiwa 277-8568, Japan

² Faculty of Information Engineering, China University of Geosciences (Wuhan), Wuhan 430074, China

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2487; https://doi.org/10.3390/s17112487 - 30 Oct 2017

Cited by 66 | Viewed by 6746

Abstract

In this study, we present the Ensemble Convolutional Neural Network (ECNN), an elaborate CNN frame formulated based on ensembling state-of-the-art CNN models, to identify village buildings from open high-resolution remote sensing (HRRS) images. First, to optimize and mine the capability of CNN for [...] Read more.

In this study, we present the Ensemble Convolutional Neural Network (ECNN), an elaborate CNN frame formulated based on ensembling state-of-the-art CNN models, to identify village buildings from open high-resolution remote sensing (HRRS) images. First, to optimize and mine the capability of CNN for village mapping and to ensure compatibility with our classification targets, a few state-of-the-art models were carefully optimized and enhanced based on a series of rigorous analyses and evaluations. Second, rather than directly implementing building identification by using these models, we exploited most of their advantages by ensembling their feature extractor parts into a stronger model called ECNN based on the multiscale feature learning method. Finally, the generated ECNN was applied to a pixel-level classification frame to implement object identification. The proposed method can serve as a viable tool for village building identification with high accuracy and efficiency. The experimental results obtained from the test area in Savannakhet province, Laos, prove that the proposed ECNN model significantly outperforms existing methods, improving overall accuracy from 96.64% to 99.26%, and kappa from 0.57 to 0.86. Full article

(This article belongs to the Special Issue Sensors and Smart Sensing of Agricultural Land Systems)

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17 pages, 4874 KiB

Open AccessArticle

Artificial Neural Network to Predict Vine Water Status Spatial Variability Using Multispectral Information Obtained from an Unmanned Aerial Vehicle (UAV)

by Tomas Poblete¹

, Samuel Ortega-Farías^1,2,*

, Miguel Angel Moreno³

and Matthew Bardeen^2,4

¹ Centro de Investigación y Transferencia en Riego y Agroclimatología (CITRA), Universidad de Talca, Casilla 747, Talca 3460000, Chile

² Research program on Adaptation of Agriculture to Climate Change (A2C2), Universidad de Talca, Casilla 747, Talca 3460000, Chile

³ Regional Centre of Water Research, University of Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain

⁴ Facultad de Ingeniería, Universidad de Talca, Curicó 3340000, Chile

Sensors 2017, 17(11), 2488; https://doi.org/10.3390/s17112488 - 30 Oct 2017

Cited by 104 | Viewed by 8489

Abstract

Water stress, which affects yield and wine quality, is often evaluated using the midday stem water potential (Ψ_stem). However, this measurement is acquired on a per plant basis and does not account for the assessment of vine water status spatial variability. [...] Read more.

Water stress, which affects yield and wine quality, is often evaluated using the midday stem water potential (Ψ_stem). However, this measurement is acquired on a per plant basis and does not account for the assessment of vine water status spatial variability. The use of multispectral cameras mounted on unmanned aerial vehicle (UAV) is capable to capture the variability of vine water stress in a whole field scenario. It has been reported that conventional multispectral indices (CMI) that use information between 500–800 nm, do not accurately predict plant water status since they are not sensitive to water content. The objective of this study was to develop artificial neural network (ANN) models derived from multispectral images to predict the Ψ_stem spatial variability of a drip-irrigated Carménère vineyard in Talca, Maule Region, Chile. The coefficient of determination (R²) obtained between ANN outputs and ground-truth measurements of Ψ_stem were between 0.56–0.87, with the best performance observed for the model that included the bands 550, 570, 670, 700 and 800 nm. Validation analysis indicated that the ANN model could estimate Ψ_stem with a mean absolute error (MAE) of 0.1 MPa, root mean square error (RMSE) of 0.12 MPa, and relative error (RE) of −9.1%. For the validation of the CMI, the MAE, RMSE and RE values were between 0.26–0.27 MPa, 0.32–0.34 MPa and −24.2–25.6%, respectively. Full article

(This article belongs to the Special Issue UAV or Drones for Remote Sensing Applications)

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16 pages, 2761 KiB

Open AccessFeature PaperArticle

Ratiometric Decoding of Pheromones for a Biomimetic Infochemical Communication System

by Guangfen Wei^1,2,*, Sanju Thomas¹, Marina Cole¹, Zoltán Rácz^1,3 and Julian W. Gardner¹

¹ Microsensors and Bioelectronics Laboratory, School of Engineering, University of Warwick, Coventry CV4 7AL, UK

² School of Information & Electronic Engineering, Shandong Technology and Business University, Yantai 264005, China

³ School of Engineering and Computing Sciences, Durham University, Durham DH1 3LE, UK

Sensors 2017, 17(11), 2489; https://doi.org/10.3390/s17112489 - 30 Oct 2017

Cited by 8 | Viewed by 5704

Abstract

Biosynthetic infochemical communication is an emerging scientific field employing molecular compounds for information transmission, labelling, and biochemical interfacing; having potential application in diverse areas ranging from pest management to group coordination of swarming robots. Our communication system comprises a chemoemitter module that encodes [...] Read more.

Biosynthetic infochemical communication is an emerging scientific field employing molecular compounds for information transmission, labelling, and biochemical interfacing; having potential application in diverse areas ranging from pest management to group coordination of swarming robots. Our communication system comprises a chemoemitter module that encodes information by producing volatile pheromone components and a chemoreceiver module that decodes the transmitted ratiometric information via polymer-coated piezoelectric Surface Acoustic Wave Resonator (SAWR) sensors. The inspiration for such a system is based on the pheromone-based communication between insects. Ten features are extracted from the SAWR sensor response and analysed using multi-variate classification techniques, i.e., Linear Discriminant Analysis (LDA), Probabilistic Neural Network (PNN), and Multilayer Perception Neural Network (MLPNN) methods, and an optimal feature subset is identified. A combination of steady state and transient features of the sensor signals showed superior performances with LDA and MLPNN. Although MLPNN gave excellent results reaching 100% recognition rate at 400 s, over all time stations PNN gave the best performance based on an expanded data-set with adjacent neighbours. In this case, 100% of the pheromone mixtures were successfully identified just 200 s after they were first injected into the wind tunnel. We believe that this approach can be used for future chemical communication employing simple mixtures of airborne molecules. Full article

(This article belongs to the Special Issue Surface Acoustic Wave and Bulk Acoustic Wave Sensors)

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27 pages, 11272 KiB

Open AccessArticle

Extrinsic Parameter Calibration for Line Scanning Cameras on Ground Vehicles with Navigation Systems Using a Calibration Pattern

by Alexander Wendel^*

and James Underwood

The Australian Centre for Field Robotics (ACFR), Department of Aerospace, Mechanical and Mechatronic Engineering (AMME), The University of Sydney, Sydney, NSW 2006, Australia

Sensors 2017, 17(11), 2491; https://doi.org/10.3390/s17112491 - 30 Oct 2017

Cited by 14 | Viewed by 5324

Abstract

Line scanning cameras, which capture only a single line of pixels, have been increasingly used in ground based mobile or robotic platforms. In applications where it is advantageous to directly georeference the camera data to world coordinates, an accurate estimate of the camera’s [...] Read more.

Line scanning cameras, which capture only a single line of pixels, have been increasingly used in ground based mobile or robotic platforms. In applications where it is advantageous to directly georeference the camera data to world coordinates, an accurate estimate of the camera’s 6D pose is required. This paper focuses on the common case where a mobile platform is equipped with a rigidly mounted line scanning camera, whose pose is unknown, and a navigation system providing vehicle body pose estimates. We propose a novel method that estimates the camera’s pose relative to the navigation system. The approach involves imaging and manually labelling a calibration pattern with distinctly identifiable points, triangulating these points from camera and navigation system data and reprojecting them in order to compute a likelihood, which is maximised to estimate the 6D camera pose. Additionally, a Markov Chain Monte Carlo (MCMC) algorithm is used to estimate the uncertainty of the offset. Tested on two different platforms, the method was able to estimate the pose to within 0.06 m/1.05

^{\circ}

and 0.18 m/2.39

^{\circ}

. We also propose several approaches to displaying and interpreting the 6D results in a human readable way. Full article

(This article belongs to the Section Physical Sensors)

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16 pages, 410 KiB

Open AccessArticle

Multi-Source Cooperative Data Collection with a Mobile Sink for the Wireless Sensor Network

by Changcai Han and Jinsheng Yang^*

School of Microelectronics, Tianjin University, Tianjin 300072, China

Sensors 2017, 17(11), 2493; https://doi.org/10.3390/s17112493 - 30 Oct 2017

Cited by 6 | Viewed by 4925

Abstract

The multi-source cooperation integrating distributed low-density parity-check codes is investigated to jointly collect data from multiple sensor nodes to the mobile sink in the wireless sensor network. The one-round and two-round cooperative data collection schemes are proposed according to the moving trajectories of [...] Read more.

The multi-source cooperation integrating distributed low-density parity-check codes is investigated to jointly collect data from multiple sensor nodes to the mobile sink in the wireless sensor network. The one-round and two-round cooperative data collection schemes are proposed according to the moving trajectories of the sink node. Specifically, two sparse cooperation models are firstly formed based on geographical locations of sensor source nodes, the impairment of inter-node wireless channels and moving trajectories of the mobile sink. Then, distributed low-density parity-check codes are devised to match the directed graphs and cooperation matrices related with the cooperation models. In the proposed schemes, each source node has quite low complexity attributed to the sparse cooperation and the distributed processing. Simulation results reveal that the proposed cooperative data collection schemes obtain significant bit error rate performance and the two-round cooperation exhibits better performance compared with the one-round scheme. The performance can be further improved when more source nodes participate in the sparse cooperation. For the two-round data collection schemes, the performance is evaluated for the wireless sensor networks with different moving trajectories and the variant data sizes. Full article

(This article belongs to the Collection Smart Communication Protocols and Algorithms for Sensor Networks)

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18 pages, 5088 KiB

Open AccessArticle

Global Calibration of Multi-Cameras Based on Refractive Projection and Ray Tracing

by Mingchi Feng^1,*

, Xiang Jia¹, Jingshu Wang², Song Feng¹ and Taixiong Zheng¹

¹ School of Advanced Manufacturing Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China

² College of Mechanical Engineering, Chongqing University of Technology, Chongqing 400054, China

Sensors 2017, 17(11), 2494; https://doi.org/10.3390/s17112494 - 31 Oct 2017

Cited by 14 | Viewed by 7648

Abstract

Multi-camera systems are widely applied in the three dimensional (3D) computer vision, especially when multiple cameras are distributed on both sides of the measured object. The calibration methods of multi-camera systems are critical to the accuracy of vision measurement and the key is [...] Read more.

Multi-camera systems are widely applied in the three dimensional (3D) computer vision, especially when multiple cameras are distributed on both sides of the measured object. The calibration methods of multi-camera systems are critical to the accuracy of vision measurement and the key is to find an appropriate calibration target. In this paper, a high-precision camera calibration method for multi-camera systems based on transparent glass checkerboards and ray tracing is described, and is used to calibrate multiple cameras distributed on both sides of the glass checkerboard. Firstly, the intrinsic parameters of each camera are obtained by Zhang’s calibration method. Then, multiple cameras capture several images from the front and back of the glass checkerboard with different orientations, and all images contain distinct grid corners. As the cameras on one side are not affected by the refraction of glass checkerboard, extrinsic parameters can be directly calculated. However, the cameras on the other side are influenced by the refraction of glass checkerboard, and the direct use of projection model will produce a calibration error. A multi-camera calibration method using refractive projection model and ray tracing is developed to eliminate this error. Furthermore, both synthetic and real data are employed to validate the proposed approach. The experimental results of refractive calibration show that the error of the 3D reconstruction is smaller than 0.2 mm, the relative errors of both rotation and translation are less than 0.014%, and the mean and standard deviation of reprojection error of the four-camera system are 0.00007 and 0.4543 pixels, respectively. The proposed method is flexible, highly accurate, and simple to carry out. Full article

(This article belongs to the Special Issue Imaging Depth Sensors—Sensors, Algorithms and Applications)

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11 pages, 3718 KiB

Open AccessArticle

The Evaluation of a Low-Cost Colorimeter for Glucose Detection in Salivary Samples

by Rocio B. Dominguez¹, Miguel A. Orozco², Giovanny Chávez² and Alfredo Márquez-Lucero^3,*

¹ CONACyT-CIMAV S.C., 31136 Chihuahua, Mexico

² Department of Engineering and Chemistry of Materials, CIMAV S.C., 31136 Chihuahua, Mexico

³ CIMAV S.C., Ejido Arroyo Seco, 34147 Durango, Mexico

Sensors 2017, 17(11), 2495; https://doi.org/10.3390/s17112495 - 1 Nov 2017

Cited by 46 | Viewed by 11626

Abstract

Given the limited access to healthcare resources, low-income settings require the development of affordable technology. Here we present the design and evaluation of a low-cost colorimeter applied to the non-invasive monitoring of Diabetes Mellitus through the detection of glucose in salival fluid. Samples [...] Read more.

Given the limited access to healthcare resources, low-income settings require the development of affordable technology. Here we present the design and evaluation of a low-cost colorimeter applied to the non-invasive monitoring of Diabetes Mellitus through the detection of glucose in salival fluid. Samples were processed by the glucose oxidase-peroxidase enzymatic system and analyzed with the development equipment. A light emission diode of 532.5 nm was used as an excitation source and a RGB module was used as a receptor. A calibration curve to quantify the concentration of salivary glucose (0 to 18 mg/dL) was carried out by relating the RGB components registered with glucose concentrations, achieving a limit of detection of 0.17 mg/dL with a CV of 5% (n = 3). Salivary samples of diabetic and healthy volunteers were processed with the equipment showing an average concentration of 1.5519 ± 0.4511 mg/dL for the first and 4.0479 ± 1.6103 mg/dL for the last, allowing a discrimination between both groups. Results were validated against a UV-Vis-NIR spectrophotometer with a correspondence of R² of 0.98194 between both instruments. Results suggest the potential application of the developed device to the sensitive detection of relevant analytes with a low-cost, user-friendly, low-power and portable instrumentation. Full article

(This article belongs to the Section Chemical Sensors)

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13 pages, 4230 KiB

Open AccessArticle

Precise Measurement of Gas Volumes by Means of Low-Offset MEMS Flow Sensors with μL/min Resolution

by Massimo Piotto¹

, Simone Del Cesta²

and Paolo Bruschi^1,2,*

¹ IEIIT-PISA, CNR, Via G. Caruso 16, 56122 Pisa, Italy

² Department of Ingegneria dell’Informazione, University of Pisa, 56122 Pisa, Italy

Sensors 2017, 17(11), 2497; https://doi.org/10.3390/s17112497 - 31 Oct 2017

Cited by 7 | Viewed by 4942

Abstract

Experiments devoted to evaluate the performance of a MEMS thermal flow sensor in measuring gas volumes are described. The sensor is a single-chip platform, including several sensing structures and a low-offset, low-noise readout interface. A recently proposed offset compensation approach is implemented obtaining [...] Read more.

Experiments devoted to evaluate the performance of a MEMS thermal flow sensor in measuring gas volumes are described. The sensor is a single-chip platform, including several sensing structures and a low-offset, low-noise readout interface. A recently proposed offset compensation approach is implemented obtaining low temperature drift and excellent long time stability. The sensor is fabricated by applying a simple micromachining procedure to a chip produced using the BCD6s process of STMicroelectronics. Application of a gas conveyor allowed inclusion of the sensing structure into a channel of sub-millimeter cross-section. The results of measurements performed by making controlled air volumes pass through the sensor channel in both directions at rates from 0.1 to 5 mL/min are described. Full article

(This article belongs to the Special Issue Integrated MEMS Sensors for the IoT Era)

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19 pages, 7135 KiB

Open AccessArticle

A Rule-Based Spatial Reasoning Approach for OpenStreetMap Data Quality Enrichment; Case Study of Routing and Navigation

by Amin Mobasheri

GIScience research group, Institute of Geography, Heidelberg University, Im Neuenheimer Feld 348, 69120 Heidelberg, Germany

Sensors 2017, 17(11), 2498; https://doi.org/10.3390/s17112498 - 31 Oct 2017

Cited by 25 | Viewed by 7591

Abstract

Finding relevant geospatial information is increasingly critical because of the growing volume of geospatial data available within the emerging “Big Data” era. Users are expecting that the availability of massive datasets will create more opportunities to uncover hidden information and answer more complex [...] Read more.

Finding relevant geospatial information is increasingly critical because of the growing volume of geospatial data available within the emerging “Big Data” era. Users are expecting that the availability of massive datasets will create more opportunities to uncover hidden information and answer more complex queries. This is especially the case with routing and navigation services where the ability to retrieve points of interest and landmarks make the routing service personalized, precise, and relevant. In this paper, we propose a new geospatial information approach that enables the retrieval of implicit information, i.e., geospatial entities that do not exist explicitly in the available source. We present an information broker that uses a rule-based spatial reasoning algorithm to detect topological relations. The information broker is embedded into a framework where annotations and mappings between OpenStreetMap data attributes and external resources, such as taxonomies, support the enrichment of queries to improve the ability of the system to retrieve information. Our method is tested with two case studies that leads to enriching the completeness of OpenStreetMap data with footway crossing points-of-interests as well as building entrances for routing and navigation purposes. It is concluded that the proposed approach can uncover implicit entities and contribute to extract required information from the existing datasets. Full article

(This article belongs to the Special Issue Crowd-Sensing and Remote Sensing Technologies for Smart Cities)

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18 pages, 9667 KiB

Open AccessArticle

Feasibility Study of the Electromagnetic Damper for Cable Structures Using Real-Time Hybrid Simulation

by Ho-Yeon Jung, In-Ho Kim

and Hyung-Jo Jung^*

Korea Advanced Institute of Science and Technology, Department of Civil and Environmental Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea

Sensors 2017, 17(11), 2499; https://doi.org/10.3390/s17112499 - 31 Oct 2017

Cited by 17 | Viewed by 6198

Abstract

Cable structure is a major component of long-span bridges, such as cable-stayed and suspension bridges, and it transfers the main loads of bridges to the pylons. As these cable structures are exposed to continuous external loads, such as vehicle and wind loads, vibration [...] Read more.

Cable structure is a major component of long-span bridges, such as cable-stayed and suspension bridges, and it transfers the main loads of bridges to the pylons. As these cable structures are exposed to continuous external loads, such as vehicle and wind loads, vibration control and continuous monitoring of the cable are required. In this study, an electromagnetic (EM) damper was designed and fabricated for vibration control and monitoring of the cable structure. EM dampers, also called regenerative dampers, consist of permanent magnets and coils. The electromagnetic force due to the relative motion between the coil and the permanent magnet can be used to control the vibration of the structure. The electrical energy can be used as a power source for the monitoring system. The effects of the design parameters of the damper were numerically analyzed and the damper was fabricated. The characteristics of the damper were analyzed with various external load changes. Finally, the vibration-control and energy-harvesting performances of the cable structure were evaluated through a hybrid simulation. The vibration-control and energy-harvesting performances for various loads were analyzed and the applicability to the cable structure of the EM damper was evaluated. Full article

(This article belongs to the Section Physical Sensors)

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13 pages, 4293 KiB

Open AccessArticle

Identification of the Rice Wines with Different Marked Ages by Electronic Nose Coupled with Smartphone and Cloud Storage Platform

by Zhebo Wei, Xize Xiao, Jun Wang^*

and Hui Wang

Department of Biosystems Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China

Sensors 2017, 17(11), 2500; https://doi.org/10.3390/s17112500 - 31 Oct 2017

Cited by 36 | Viewed by 5601

Abstract

In this study, a portable electronic nose (E-nose) was self-developed to identify rice wines with different marked ages—all the operations of the E-nose were controlled by a special Smartphone Application. The sensor array of the E-nose was comprised of 12 MOS sensors and [...] Read more.

In this study, a portable electronic nose (E-nose) was self-developed to identify rice wines with different marked ages—all the operations of the E-nose were controlled by a special Smartphone Application. The sensor array of the E-nose was comprised of 12 MOS sensors and the obtained response values were transmitted to the Smartphone thorough a wireless communication module. Then, Aliyun worked as a cloud storage platform for the storage of responses and identification models. The measurement of the E-nose was composed of the taste information obtained phase (TIOP) and the aftertaste information obtained phase (AIOP). The area feature data obtained from the TIOP and the feature data obtained from the TIOP-AIOP were applied to identify rice wines by using pattern recognition methods. Principal component analysis (PCA), locally linear embedding (LLE) and linear discriminant analysis (LDA) were applied for the classification of those wine samples. LDA based on the area feature data obtained from the TIOP-AIOP proved a powerful tool and showed the best classification results. Partial least-squares regression (PLSR) and support vector machine (SVM) were applied for the predictions of marked ages and SVM (R² = 0.9942) worked much better than PLSR. Full article

(This article belongs to the Special Issue Electronic Tongues and Electronic Noses)

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19 pages, 10183 KiB

Open AccessArticle

Multi-Sensor Information Fusion for Optimizing Electric Bicycle Routes Using a Swarm Intelligence Algorithm

by Daniel H. De La Iglesia^1,*

, Gabriel Villarrubia¹

, Juan F. De Paz¹ and Javier Bajo²

¹ Computer and Automation Department, University of Salamanca, Plaza de la Merced s/n, 37002 Salamanca, Spain

² Artificial Intelligence Department, Polytechnic University of Madrid, Campus Montegancedo s/n, Boadilla del Monte, 28660 Madrid, Spain

Sensors 2017, 17(11), 2501; https://doi.org/10.3390/s17112501 - 31 Oct 2017

Cited by 25 | Viewed by 9436

Abstract

The use of electric bikes (e-bikes) has grown in popularity, especially in large cities where overcrowding and traffic congestion are common. This paper proposes an intelligent engine management system for e-bikes which uses the information collected from sensors to optimize battery energy and [...] Read more.

The use of electric bikes (e-bikes) has grown in popularity, especially in large cities where overcrowding and traffic congestion are common. This paper proposes an intelligent engine management system for e-bikes which uses the information collected from sensors to optimize battery energy and time. The intelligent engine management system consists of a built-in network of sensors in the e-bike, which is used for multi-sensor data fusion; the collected data is analysed and fused and on the basis of this information the system can provide the user with optimal and personalized assistance. The user is given recommendations related to battery consumption, sensors, and other parameters associated with the route travelled, such as duration, speed, or variation in altitude. To provide a user with these recommendations, artificial neural networks are used to estimate speed and consumption for each of the segments of a route. These estimates are incorporated into evolutionary algorithms in order to make the optimizations. A comparative analysis of the results obtained has been conducted for when routes were travelled with and without the optimization system. From the experiments, it is evident that the use of an engine management system results in significant energy and time savings. Moreover, user satisfaction increases as the level of assistance adapts to user behavior and the characteristics of the route. Full article

(This article belongs to the Special Issue Smart Vehicular Mobile Sensing)

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14 pages, 6360 KiB

Open AccessArticle

COALA: A Protocol for the Avoidance and Alleviation of Congestion in Wireless Sensor Networks

by Dionisis Kandris^1,*

, George Tselikis², Eleftherios Anastasiadis³, Emmanouil Panaousis⁴

and Tasos Dagiuklas³

¹ Department of Electronic Engineering, Technological Educational Institute of Athens, 12243 Athens, Greece

² Department of Computer Systems Engineering, Piraeus University of Applied Sciences, 12241 Athens, Greece

³ School of Engineering/Computer Science and Informatics, London South Bank University, London SE1 0AA, UK

⁴ Department of Computer Science, University of Surrey, Guildford GU2 7XH, UK

Sensors 2017, 17(11), 2502; https://doi.org/10.3390/s17112502 - 31 Oct 2017

Cited by 21 | Viewed by 5067

Abstract

The occurrence of congestion has an extremely deleterious impact on the performance of Wireless Sensor Networks (WSNs). This article presents a novel protocol, named COALA (COngestion ALleviation and Avoidance), which aims to act both proactively, in order to avoid the creation [...] Read more.

The occurrence of congestion has an extremely deleterious impact on the performance of Wireless Sensor Networks (WSNs). This article presents a novel protocol, named COALA (COngestion ALleviation and Avoidance), which aims to act both proactively, in order to avoid the creation of congestion in WSNs, and reactively, so as to mitigate the diffusion of upcoming congestion through alternative path routing. Its operation is based on the utilization of an accumulative cost function, which considers both static and dynamic metrics in order to send data through the paths that are less probable to be congested. COALA is validated through simulation tests, which exhibit its ability to achieve remarkable reduction of loss ratios, transmission delays and energy dissipation. Moreover, the appropriate adjustment of the weighting of the accumulative cost function enables the algorithm to adapt to the performance criteria of individual case scenarios. Full article

(This article belongs to the Special Issue Soft Sensors and Intelligent Algorithms for Data Fusion)

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11 pages, 2388 KiB

Open AccessArticle

Impedance-Based Living Cell Analysis for Clinical Diagnosis of Type I Allergy

by Reiko Irifuku, Yuhki Yanase, Tomoko Kawaguchi, Kaori Ishii, Shunsuke Takahagi and Michihiro Hide^*

Department of Dermatology, Graduate School of Biomedical and Health Science, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan

Sensors 2017, 17(11), 2503; https://doi.org/10.3390/s17112503 - 31 Oct 2017

Cited by 6 | Viewed by 4721

Abstract

Non-invasive real time evaluation of living cell conditions and functions are increasingly desired in the field of clinical diagnosis. For diagnosis of type I allergy, the identification of antigens that induces activation of mast cells and basophils is crucial to avoid symptoms of [...] Read more.

Non-invasive real time evaluation of living cell conditions and functions are increasingly desired in the field of clinical diagnosis. For diagnosis of type I allergy, the identification of antigens that induces activation of mast cells and basophils is crucial to avoid symptoms of allergic diseases. However, conventional tests, such as detection of antigen-specific IgE antibody and skin tests, are either of low reliability or are invasive. To overcome such problems, we hereby applied an impedance sensor for label-free and real-time monitoring of mast cell reactions in response to stimuli. When IgE-sensitized RBL-2H3 cells cultured on the electrodes were stimulated with various concentrations of antigens, dose-dependent cell index (CI) increases were detected. Moreover, we confirmed that the impedance sensor detected morphological changes rather than degranulation as the indicator of cell activation. Furthermore, the CI of human IgE receptor-expressing cells (RBL-48 cells) treated with serum of a sweat allergy-positive patient, but not with serum from a sweat allergy-negative patient, significantly increased in response to purified human sweat antigen. We thus developed a technique to detect the activation of living cells in response to stimuli without any labeling using the impedance sensor. This system may represent a high reliable tool for the diagnosis of type I allergy. Full article

(This article belongs to the Special Issue Sensors for Health Monitoring and Disease Diagnosis)

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20 pages, 1094 KiB

Open AccessArticle

A Novel Evidence Theory and Fuzzy Preference Approach-Based Multi-Sensor Data Fusion Technique for Fault Diagnosis

by Fuyuan Xiao

School of Computer and Information Science, Southwest University, No. 2 Tiansheng Road, BeiBei District, Chongqing 400715, China

Sensors 2017, 17(11), 2504; https://doi.org/10.3390/s17112504 - 31 Oct 2017

Cited by 88 | Viewed by 6141

Abstract

The multi-sensor data fusion technique plays a significant role in fault diagnosis and in a variety of such applications, and the Dempster–Shafer evidence theory is employed to improve the system performance; whereas, it may generate a counter-intuitive result when the pieces of evidence [...] Read more.

The multi-sensor data fusion technique plays a significant role in fault diagnosis and in a variety of such applications, and the Dempster–Shafer evidence theory is employed to improve the system performance; whereas, it may generate a counter-intuitive result when the pieces of evidence highly conflict with each other. To handle this problem, a novel multi-sensor data fusion approach on the basis of the distance of evidence, belief entropy and fuzzy preference relation analysis is proposed. A function of evidence distance is first leveraged to measure the conflict degree among the pieces of evidence; thus, the support degree can be obtained to represent the reliability of the evidence. Next, the uncertainty of each piece of evidence is measured by means of the belief entropy. Based on the quantitative uncertainty measured above, the fuzzy preference relations are applied to represent the relative credibility preference of the evidence. Afterwards, the support degree of each piece of evidence is adjusted by taking advantage of the relative credibility preference of the evidence that can be utilized to generate an appropriate weight with respect to each piece of evidence. Finally, the modified weights of the evidence are adopted to adjust the bodies of the evidence in the advance of utilizing Dempster’s combination rule. A numerical example and a practical application in fault diagnosis are used as illustrations to demonstrate that the proposal is reasonable and efficient in the management of conflict and fault diagnosis. Full article

(This article belongs to the Special Issue Advances in Multi-Sensor Information Fusion: Theory and Applications 2017)

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17 pages, 6160 KiB

Open AccessArticle

Design, Fabrication, and Modeling of a Novel Dual-Axis Control Input PZT Gyroscope

by Cheng-Yang Chang and Tsung-Lin Chen^*

Department of Mechanical Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan

Sensors 2017, 17(11), 2505; https://doi.org/10.3390/s17112505 - 31 Oct 2017

Cited by 8 | Viewed by 4229

Abstract

Conventional gyroscopes are equipped with a single-axis control input, limiting their performance. Although researchers have proposed control algorithms with dual-axis control inputs to improve gyroscope performance, most have verified the control algorithms through numerical simulations because they lacked practical devices with dual-axis control [...] Read more.

Conventional gyroscopes are equipped with a single-axis control input, limiting their performance. Although researchers have proposed control algorithms with dual-axis control inputs to improve gyroscope performance, most have verified the control algorithms through numerical simulations because they lacked practical devices with dual-axis control inputs. The aim of this study was to design a piezoelectric gyroscope equipped with a dual-axis control input so that researchers may experimentally verify those control algorithms in future. Designing a piezoelectric gyroscope with a dual-axis control input is more difficult than designing a conventional gyroscope because the control input must be effective over a broad frequency range to compensate for imperfections, and the multiple mode shapes in flexural deformations complicate the relation between flexural deformation and the proof mass position. This study solved these problems by using a lead zirconate titanate (PZT) material, introducing additional electrodes for shielding, developing an optimal electrode pattern, and performing calibrations of undesired couplings. The results indicated that the fabricated device could be operated at 5.5±1 kHz to perform dual-axis actuations and position measurements. The calibration of the fabricated device was completed by system identifications of a new dynamic model including gyroscopic motions, electromechanical coupling, mechanical coupling, electrostatic coupling, and capacitive output impedance. Finally, without the assistance of control algorithms, the “open loop sensitivity” of the fabricated gyroscope was 1.82 μV/deg/s with a nonlinearity of 9.5% full-scale output. This sensitivity is comparable with those of other PZT gyroscopes with single-axis control inputs. Full article

(This article belongs to the Section Physical Sensors)

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21 pages, 5683 KiB

Open AccessArticle

Two-Stage Multi-Task Representation Learning for Synthetic Aperture Radar (SAR) Target Images Classification

by Xinzheng Zhang^1,*, Yijian Wang¹, Zhiying Tan¹, Dong Li², Shujun Liu¹, Tao Wang² and Yongming Li¹

¹ College of Communication Engineering, Chongqing University, Chongqing 400044, China

² Key Laboratory of Aerocraft Tracking Telementering & Command and Communication, Chongqing University, Chongqing 400044, China

Sensors 2017, 17(11), 2506; https://doi.org/10.3390/s17112506 - 1 Nov 2017

Cited by 12 | Viewed by 4581

Abstract

In this paper, we propose a two-stage multi-task learning representation method for the classification of synthetic aperture radar (SAR) target images. The first stage of the proposed approach uses multi-features joint sparse representation learning, modeled as a

ℓ_{2, 1}

-norm regularized [...] Read more.

In this paper, we propose a two-stage multi-task learning representation method for the classification of synthetic aperture radar (SAR) target images. The first stage of the proposed approach uses multi-features joint sparse representation learning, modeled as a

ℓ_{2, 1}

-norm regularized multi-task sparse learning problem, to find an effective subset of training samples. Then, a new dictionary is constructed based on the training subset. The second stage of the method is to perform target images classification based on the new dictionary, utilizing multi-task collaborative representation. The proposed algorithm not only exploits the discrimination ability of multiple features but also greatly reduces the interference of atoms that are irrelevant to the test sample, thus effectively improving classification performance. Conducted with the Moving and Stationary Target Acquisition and Recognition (MSTAR) public SAR database, experimental results show that the proposed approach is effective and superior to many state-of-the-art methods. Full article

(This article belongs to the Section Remote Sensors)

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12 pages, 2834 KiB

Open AccessArticle

A Pattern Recognition Approach to Acoustic Emission Data Originating from Fatigue of Wind Turbine Blades

by Jialin Tang^1,2,*, Slim Soua¹, Cristinel Mares² and Tat-Hean Gan^1,2

¹ Integrity Management Group, TWI Ltd., Cambridge CB21 6AL, UK

² College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH, UK

Sensors 2017, 17(11), 2507; https://doi.org/10.3390/s17112507 - 1 Nov 2017

Cited by 62 | Viewed by 6676

Abstract

The identification of particular types of damage in wind turbine blades using acoustic emission (AE) techniques is a significant emerging field. In this work, a 45.7-m turbine blade was subjected to flap-wise fatigue loading for 21 days, during which AE was measured by [...] Read more.

The identification of particular types of damage in wind turbine blades using acoustic emission (AE) techniques is a significant emerging field. In this work, a 45.7-m turbine blade was subjected to flap-wise fatigue loading for 21 days, during which AE was measured by internally mounted piezoelectric sensors. This paper focuses on using unsupervised pattern recognition methods to characterize different AE activities corresponding to different fracture mechanisms. A sequential feature selection method based on a k-means clustering algorithm is used to achieve a fine classification accuracy. The visualization of clusters in peak frequency−frequency centroid features is used to correlate the clustering results with failure modes. The positions of these clusters in time domain features, average frequency−MARSE, and average frequency−peak amplitude are also presented in this paper (where MARSE represents the Measured Area under Rectified Signal Envelope). The results show that these parameters are representative for the classification of the failure modes. Full article

(This article belongs to the Special Issue Sensor Technologies for Health Monitoring of Composite Structures)

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14 pages, 1812 KiB

Open AccessArticle

A Code Division Design Strategy for Multiplexing Fiber Bragg Grating Sensing Networks

by Andrés Triana^1,2

, Daniel Pastor^1,*

and Margarita Varón²

¹ Photonics Research Labs (PRL), Universitat Politècnica de València, 46022 Valencia, Spain

² Electric and Electronics Department, Universidad Nacional de Colombia sede Bogotá, Bogotá D.C. 111321, Colombia

Sensors 2017, 17(11), 2508; https://doi.org/10.3390/s17112508 - 1 Nov 2017

Cited by 14 | Viewed by 5763

Abstract

In this paper, an encoding strategy is used to design specialized fiber Bragg grating (FBG) sensors. The encoding of each sensor requires two binary codewords to define the amplitude and phase patterns of each sensor. The combined pattern (amplitude and phase) makes each [...] Read more.

In this paper, an encoding strategy is used to design specialized fiber Bragg grating (FBG) sensors. The encoding of each sensor requires two binary codewords to define the amplitude and phase patterns of each sensor. The combined pattern (amplitude and phase) makes each sensor unique and therefore two or more sensors can be identified under spectral overlapping. In this way, we add another dimension to the multiplexing of FBG sensors, obtaining an increase factor ‘n’ to enhance the number of sensors that the system can handle. A proof-of-concept scenario with three sensors was performed, including the manufacturing of the encoded sensors. Furthermore, an interrogation setup to detect the sensors central wavelength was proposed and its working principle was theoretically developed. Results show that total identification of the central wavelength is performed under spectral overlapping between the manufactured sensors, achieving a three-time improvement of the system capacity. Finally, the error due to overlapping between the sensors was assessed obtaining approximately 3 pm, which makes the approach suitable for use in real measurement systems. Full article

(This article belongs to the Special Issue Fiber Bragg Grating Based Sensors)

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14 pages, 5254 KiB

Open AccessArticle

Design and Electro-Thermo-Mechanical Behavior Analysis of Au/Si₃N₄ Bimorph Microcantilevers for Static Mode Sensing

by Seok-Won Kang^1,2,*

, Joe Fragala³

, Su-Ho Kim^1,4 and Debjyoti Banerjee⁵

¹ Korea Railroad Research Institute, 176 Cheoldo bangmulgwan-ro, Uiwang 16105, Gyeonggi-do, Korea

² Division of Energy Environment Technology, University of Science & Technology (UST), Daejeon 34113, Korea

³ NanoINK, Inc., 215 E Hacienda Ave., Campbell, CA 95008, USA

⁴ School of Mechanical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea

⁵ Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA

Sensors 2017, 17(11), 2510; https://doi.org/10.3390/s17112510 - 1 Nov 2017

Cited by 8 | Viewed by 5498

Abstract

This paper presents a design optimization method based on theoretical analysis and numerical calculations, using a commercial multi-physics solver (e.g., ANSYS and ESI CFD-ACE+), for a 3D continuous model, to analyze the bending characteristics of an electrically heated bimorph microcantilever. The results from [...] Read more.

This paper presents a design optimization method based on theoretical analysis and numerical calculations, using a commercial multi-physics solver (e.g., ANSYS and ESI CFD-ACE+), for a 3D continuous model, to analyze the bending characteristics of an electrically heated bimorph microcantilever. The results from the theoretical calculation and numerical analysis are compared with those measured using a CCD camera and magnification lenses for a chip level microcantilever array fabricated in this study. The bimorph microcantilevers are thermally actuated by joule heating generated by a 0.4 μm thin-film Au heater deposited on 0.6 μm Si₃N₄ microcantilevers. The initial deflections caused by residual stress resulting from the thermal bonding of two metallic layers with different coefficients of thermal expansion (CTEs) are additionally considered, to find the exact deflected position. The numerically calculated total deflections caused by electrical actuation show differences of 10%, on average, with experimental measurements in the operating current region (i.e., ~25 mA) to prevent deterioration by overheating. Bimorph microcantilevers are promising components for use in various MEMS (Micro-Electro-Mechanical System) sensing applications, and their deflection characteristics in static mode sensing are essential for detecting changes in thermal stress on the surface of microcantilevers. Full article

(This article belongs to the Section Physical Sensors)

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15 pages, 1884 KiB

Open AccessArticle

Smart Collaborative Caching for Information-Centric IoT in Fog Computing

by Fei Song¹, Zheng-Yang Ai¹, Jun-Jie Li², Giovanni Pau³

, Mario Collotta³

, Ilsun You^4,*

and Hong-Ke Zhang¹

¹ School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044, China

² Institute of Education and Economy Research, University of International Business and Economics, Beijing 100029, China

³ Faculty of Engineering and Architecture, Kore University of Enna, 94100 Enna, Italy

⁴ Department of Information Security Engineering, Soonchunhyang University, Asan-si 31538, Korea

Sensors 2017, 17(11), 2512; https://doi.org/10.3390/s17112512 - 1 Nov 2017

Cited by 67 | Viewed by 6806

Abstract

The significant changes enabled by the fog computing had demonstrated that Internet of Things (IoT) urgently needs more evolutional reforms. Limited by the inflexible design philosophy; the traditional structure of a network is hard to meet the latest demands. However, Information-Centric Networking (ICN) [...] Read more.

The significant changes enabled by the fog computing had demonstrated that Internet of Things (IoT) urgently needs more evolutional reforms. Limited by the inflexible design philosophy; the traditional structure of a network is hard to meet the latest demands. However, Information-Centric Networking (ICN) is a promising option to bridge and cover these enormous gaps. In this paper, a Smart Collaborative Caching (SCC) scheme is established by leveraging high-level ICN principles for IoT within fog computing paradigm. The proposed solution is supposed to be utilized in resource pooling, content storing, node locating and other related situations. By investigating the available characteristics of ICN, some challenges of such combination are reviewed in depth. The details of building SCC, including basic model and advanced algorithms, are presented based on theoretical analysis and simplified examples. The validation focuses on two typical scenarios: simple status inquiry and complex content sharing. The number of clusters, packet loss probability and other parameters are also considered. The analytical results demonstrate that the performance of our scheme, regarding total packet number and average transmission latency, can outperform that of the original ones. We expect that the SCC will contribute an efficient solution to the related studies. Full article

(This article belongs to the Special Issue Next Generation Wireless Technologies for Internet of Things)

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12 pages, 9707 KiB

Open AccessArticle

High-Accuracy Readout Electronics for Piezoresistive Tactile Sensors

by José A. Hidalgo-López^1,*

, Óscar Oballe-Peinado^1,2

, Julián Castellanos-Ramos^1,2

, José A. Sánchez-Durán^1,2

, Raquel Fernández-Ramos¹

and Fernando Vidal-Verdú^1,2

¹ Departamento de Electrónica, Universidad de Málaga, Andalucía Tech, Campus de Teatinos, Málaga 29071, Spain

² Instituto de Investigación Biomédica de Málaga (IBIMA), Málaga 29010, Spain

Sensors 2017, 17(11), 2513; https://doi.org/10.3390/s17112513 - 1 Nov 2017

Cited by 29 | Viewed by 7117

Abstract

The typical layout in a piezoresistive tactile sensor arranges individual sensors to form an array with M rows and N columns. While this layout reduces the wiring involved, it does not allow the values of the sensor resistors to be measured individually due [...] Read more.

The typical layout in a piezoresistive tactile sensor arranges individual sensors to form an array with M rows and N columns. While this layout reduces the wiring involved, it does not allow the values of the sensor resistors to be measured individually due to the appearance of crosstalk caused by the nonidealities of the array reading circuits. In this paper, two reading methods that minimize errors resulting from this phenomenon are assessed by designing an electronic system for array reading, and the results are compared to those obtained using the traditional method, obviating the nonidealities of the reading circuit. The different models were compared by testing the system with an array of discrete resistors. The system was later connected to a tactile sensor with 8 × 7 taxels. Full article

(This article belongs to the Special Issue Tactile Sensors and Sensing)

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36 pages, 1696 KiB

Open AccessArticle

Multipass Target Search in Natural Environments

by Michael J. Kuhlman^1,*, Michael W. Otte², Donald Sofge³ and Satyandra K. Gupta⁴

¹ Institute for Systems Research, Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA

² National Research Council RAP Postdoctoral Associate at Naval Research Laboratory, Washington, DC 20375, USA

³ Navy Center for Applied Research in Artificial Intelligence, Naval Research Laboratory, Washington, DC 20375, USA

⁴ Center for Advanced Manufacturing, Aerospace and Mechanical Engineering Department, University of Southern California, Los Angeles, CA 90089, USA

Sensors 2017, 17(11), 2514; https://doi.org/10.3390/s17112514 - 2 Nov 2017

Cited by 8 | Viewed by 4660

Abstract

Consider a disaster scenario where search and rescue workers must search difficult to access buildings during an earthquake or flood. Often, finding survivors a few hours sooner results in a dramatic increase in saved lives, suggesting the use of drones for expedient rescue [...] Read more.

Consider a disaster scenario where search and rescue workers must search difficult to access buildings during an earthquake or flood. Often, finding survivors a few hours sooner results in a dramatic increase in saved lives, suggesting the use of drones for expedient rescue operations. Entropy can be used to quantify the generation and resolution of uncertainty. When searching for targets, maximizing mutual information of future sensor observations will minimize expected target location uncertainty by minimizing the entropy of the future estimate. Motion planning for multi-target autonomous search requires planning over an area with an imperfect sensor and may require multiple passes, which is hindered by the submodularity property of mutual information. Further, mission duration constraints must be handled accordingly, requiring consideration of the vehicle’s dynamics to generate feasible trajectories and must plan trajectories spanning the entire mission duration, something which most information gathering algorithms are incapable of doing. If unanticipated changes occur in an uncertain environment, new plans must be generated quickly. In addition, planning multipass trajectories requires evaluating path dependent rewards, requiring planning in the space of all previously selected actions, compounding the problem. We present an anytime algorithm for autonomous multipass target search in natural environments. The algorithm is capable of generating long duration dynamically feasible multipass coverage plans that maximize mutual information using a variety of techniques such as

ϵ

-admissible heuristics to speed up the search. To the authors’ knowledge this is the first attempt at efficiently solving multipass target search problems of such long duration. The proposed algorithm is based on best first branch and bound and is benchmarked against state of the art algorithms adapted to the problem in natural Simplex environments, gathering the most information in the given search time. Full article

(This article belongs to the Special Issue Remote Sensing and GIS for Geo-Hazards and Disasters)

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12 pages, 12234 KiB

Open AccessArticle

Concept and Evaluation of a New Piezoelectric Transducer for an Implantable Middle Ear Hearing Device

by Houguang Liu¹

, Jinlei Cheng², Jianhua Yang¹, Zhushi Rao^2,*, Gang Cheng¹, Shanguo Yang¹, Xinsheng Huang³ and Mengli Wang¹

¹ School of Mechatronic Engineering, China University of Mining and Technology, Xuzhou 221116, China

² State Key Laboratory of Mechanical System and Vibrations, Shanghai Jiaotong University, Shanghai 200240, China

³ Department of Otorhinolaryngology, Zhongshan Hospital affiliated to Fudan University, Shanghai 200032, China

Sensors 2017, 17(11), 2515; https://doi.org/10.3390/s17112515 - 2 Nov 2017

Cited by 21 | Viewed by 7125

Abstract

Implantable middle ear hearing devices (IMEHDs) have been developed as a new technology to overcome the limitations of conventional hearing aids. The piezoelectric cantilever transducers currently used in the IMEHDs have the advantages of low power consumption and ease of fabrication, but generate [...] Read more.

Implantable middle ear hearing devices (IMEHDs) have been developed as a new technology to overcome the limitations of conventional hearing aids. The piezoelectric cantilever transducers currently used in the IMEHDs have the advantages of low power consumption and ease of fabrication, but generate less high-frequency output. To address this problem, we proposed and designed a new piezoelectric transducer based on a piezoelectric stack for the IMEHD. This new transducer, attached to the incus body with a coupling rod, stimulates the ossicular chain in response to the expansion-and-contraction of its piezoelectric stack. To test its feasibility for hearing loss compensation, a bench testing of the transducer prototype and a temporal bone experiment were conducted, respectively. Bench testing results showed that the new transducer did have a broad frequency bandwidth. Besides, the transducer was found to have a low total harmonic distortion (<0.75%) in all frequencies, and small release time (1 ms). The temporal bone experiment further proved that the transducer has the capability to produce sufficient vibrations to compensate for severe sensorineural hearing loss, especially at high frequencies. This property benefits the treatment of the most common sloping high-frequency sensorineural hearing loss. To produce a 100 dB SPL equivalent sound pressure at 1 kHz, its power consumption is 0.49 mW, which is low enough for the transducer to be utilized in the IMEHD. Full article

(This article belongs to the Special Issue Implantable Sensors 2018)

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16 pages, 6998 KiB

Open AccessArticle

Experimental Investigation of the Piezoresistive Properties of Cement Composites with Hybrid Carbon Fibers and Nanotubes

by Seung-Jung Lee¹, Ilhwan You², Goangseup Zi² and Doo-Yeol Yoo^3,*

¹ Future Strategy Center, Korea Railroad Research Institute, 176 Cheoldobangmulgwan-ro, Uiwang-si, Gyeonggi-do 16105, Korea

² School of Civil, Environmental and Architectural Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Korea

³ Department of Architectural Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea

Sensors 2017, 17(11), 2516; https://doi.org/10.3390/s17112516 - 2 Nov 2017

Cited by 105 | Viewed by 8047

Abstract

Cement-based sensors with hybrid conductive fillers using both carbon fibers (CFs) and multi-walled carbon nanotubes (MWCNTs) were experimentally investigated in this study. The self-sensing capacities of cement-based composites with only CFs or MWCNTs were found based on preliminary tests. The results showed that [...] Read more.

Cement-based sensors with hybrid conductive fillers using both carbon fibers (CFs) and multi-walled carbon nanotubes (MWCNTs) were experimentally investigated in this study. The self-sensing capacities of cement-based composites with only CFs or MWCNTs were found based on preliminary tests. The results showed that the percolation thresholds of CFs and MWCNTs were 0.5–1.0 vol.% and 1.0 vol.%, respectively. Based on these results, the feasibility of self-sensing composites with four different amounts of CFs and MWCNTs was considered under cyclic compression loads. When the amount of incorporated CFs increased and the amount of incorporated MWCNTs decreased, the self-sensing capacity of the composites was reduced. It was concluded that cement-based composites containing both 0.1 vol.% CFs and 0.5 vol.% MWCNTs could be an alternative to cement-based composites with 1.0 vol.% MWCNTs in order to achieve equivalent self-sensing performance at half the price. The gauge factor (GF) for that composite was 160.3 with an R-square of 0.9274 in loading stages I and II, which was similar to the GF of 166.6 for the composite with 1.0 vol.% MWCNTs. Full article

(This article belongs to the Section Physical Sensors)

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10 pages, 2723 KiB

Open AccessArticle

A Ratiometric Fluorescent Sensor for Cd²⁺ Based on Internal Charge Transfer

by Dandan Cheng^1,†, Xingliang Liu^1,†, Yadian Xie¹, Haitang Lv¹, Zhaoqian Wang¹, Hongzhi Yang¹, Aixia Han^1,2,*, Xiaomei Yang² and Ling Zang^2,*

¹ Chemical Engineering College, Qinghai University, Xining 810016, China

² Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84108, USA

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2517; https://doi.org/10.3390/s17112517 - 2 Nov 2017

Cited by 40 | Viewed by 9697

Abstract

This work reports on a novel fluorescent sensor 1 for Cd²⁺ ion based on the fluorophore of tetramethyl substituted bis(difluoroboron)-1,2-bis[(1H-pyrrol-2-yl)methylene]hydrazine (Me₄BOPHY), which is modified with an electron donor moiety of N,N-bis(pyridin-2-ylmethyl)benzenamine. Sensor 1 has absorption [...] Read more.

This work reports on a novel fluorescent sensor 1 for Cd²⁺ ion based on the fluorophore of tetramethyl substituted bis(difluoroboron)-1,2-bis[(1H-pyrrol-2-yl)methylene]hydrazine (Me₄BOPHY), which is modified with an electron donor moiety of N,N-bis(pyridin-2-ylmethyl)benzenamine. Sensor 1 has absorption and emission in visible region, at 550 nm and 675 nm, respectively. The long wavelength spectral response makes it easier to fabricate the fluorescence detector. The sensor mechanism is based on the tunable internal charge transfer (ICT) transition of molecule 1. Binding of Cd²⁺ ion quenches the ICT transition, but turns on the π − π transition of the fluorophore, thus enabling ratiometric fluorescence sensing. The limit of detection (LOD) was projected down to 0.77 ppb, which is far below the safety value (3 ppb) set for drinking water by World Health Organization. The sensor also demonstrates a high selectivity towards Cd²⁺ in comparison to other interferent metal ions. Full article

(This article belongs to the Special Issue Fluorescent Probes and Sensors)

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16 pages, 6491 KiB

Open AccessArticle

Local Positioning System Using Flickering Infrared LEDs

by Thibaut Raharijaona^1,*, Rodolphe Mawonou¹, Thanh Vu Nguyen¹, Fabien Colonnier^1,2, Marc Boyron¹, Julien Diperi¹ and Stéphane Viollet¹

¹ Aix Marseille University, CNRS, ISM, Marseille 13009 , France

² Temasek Labs, National University of Singapore, Singapore 117411, Singapore

Sensors 2017, 17(11), 2518; https://doi.org/10.3390/s17112518 - 3 Nov 2017

Cited by 40 | Viewed by 11605

Abstract

A minimalistic optical sensing device for the indoor localization is proposed to estimate the relative position between the sensor and active markers using amplitude modulated infrared light. The innovative insect-based sensor can measure azimuth and elevation angles with respect to two small and [...] Read more.

A minimalistic optical sensing device for the indoor localization is proposed to estimate the relative position between the sensor and active markers using amplitude modulated infrared light. The innovative insect-based sensor can measure azimuth and elevation angles with respect to two small and cheap active infrared light emitting diodes (LEDs) flickering at two different frequencies. In comparison to a previous lensless visual sensor that we proposed for proximal localization (less than 30 cm), we implemented: (i) a minimalistic sensor in terms of small size (10 cm

^{3}

), light weight (6 g) and low power consumption (0.4 W); (ii) an Arduino-compatible demodulator for fast analog signal processing requiring low computational resources; and (iii) an indoor positioning system for a mobile robotic application. Our results confirmed that the proposed sensor was able to estimate the position at a distance of 2 m with an accuracy as small as 2-cm at a sampling frequency of 100 Hz. Our sensor can be also suitable to be implemented in a position feedback loop for indoor robotic applications in GPS-denied environment. Full article

(This article belongs to the Special Issue Sensors and Sensing in Indoor Localization, Tracking, Navigation and Activity Monitoring)

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11 pages, 5709 KiB

Open AccessArticle

Femtosecond FBG Written through the Coating for Sensing Applications

by Joé Habel^1,*, Tommy Boilard¹, Jean-Simon Frenière¹, François Trépanier²

and Martin Bernier¹

¹ Center for Optics, Photonics, and Lasers (COPL), Université Laval, Québec, QC G1K 7P4, Canada

² TeraXion Inc., Québec, QC G1P 4S8, Canada

Sensors 2017, 17(11), 2519; https://doi.org/10.3390/s17112519 - 2 Nov 2017

Cited by 84 | Viewed by 7750

Abstract

Type I fiber Bragg gratings (FBG) written through the coating of various off-the-shelf silica fibers with a femtosecond laser and the phase-mask technique are reported. Inscription through most of the common coating compositions (acrylate, silicone and polyimide) is reported as well as writing [...] Read more.

Type I fiber Bragg gratings (FBG) written through the coating of various off-the-shelf silica fibers with a femtosecond laser and the phase-mask technique are reported. Inscription through most of the common coating compositions (acrylate, silicone and polyimide) is reported as well as writing through the polyimide coating of various fiber cladding diameters, down to 50 µm. The long term annealing behavior of type I gratings written in a pure silica core fiber is also reported as well as a comparison of the mechanical resistance of type I and II FBG. The high mechanical resistance of the resulting type I FBG is shown to be useful for the fabrication of various distributed FBG arrays written using a single period phase-mask. The strain sensing response of such distributed arrays is also presented. Full article

(This article belongs to the Special Issue Fiber Bragg Grating Based Sensors)

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17 pages, 2644 KiB

Open AccessArticle

Device-Free Passive Identity Identification via WiFi Signals

by Jiguang Lv

, Wu Yang^* and Dapeng Man

Information Security Research Center, Harbin Engineering University, Harbin 150001, China

Sensors 2017, 17(11), 2520; https://doi.org/10.3390/s17112520 - 2 Nov 2017

Cited by 32 | Viewed by 5918

Abstract

Device-free passive identity identification attracts much attention in recent years, and it is a representative application in sensorless sensing. It can be used in many applications such as intrusion detection and smart building. Previous studies show the sensing potential of WiFi signals in [...] Read more.

Device-free passive identity identification attracts much attention in recent years, and it is a representative application in sensorless sensing. It can be used in many applications such as intrusion detection and smart building. Previous studies show the sensing potential of WiFi signals in a device-free passive manner. It is confirmed that human’s gait is unique from each other similar to fingerprint and iris. However, the identification accuracy of existing approaches is not satisfactory in practice. In this paper, we present Wii, a device-free WiFi-based Identity Identification approach utilizing human’s gait based on Channel State Information (CSI) of WiFi signals. Principle Component Analysis (PCA) and low pass filter are applied to remove the noises in the signals. We then extract several entities’ gait features from both time and frequency domain, and select the most effective features according to information gain. Based on these features, Wii realizes stranger recognition through Gaussian Mixture Model (GMM) and identity identification through a Support Vector Machine (SVM) with Radial Basis Function (RBF) kernel. It is implemented using commercial WiFi devices and evaluated on a dataset with more than 1500 gait instances collected from eight subjects walking in a room. The results indicate that Wii can effectively recognize strangers and can achieves high identification accuracy with low computational cost. As a result, Wii has the potential to work in typical home security systems. Full article

(This article belongs to the Section Sensor Networks)

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14 pages, 6800 KiB

Open AccessArticle

A Simple Assay for Ultrasensitive Colorimetric Detection of Ag⁺ at Picomolar Levels Using Platinum Nanoparticles

by Yi-Wei Wang¹, Meili Wang², Lixing Wang¹, Hui Xu¹, Shurong Tang^3,*, Huang-Hao Yang², Lan Zhang^2,* and Hongbo Song^1,*

¹ Key Laboratory of Predictive Microbiology and Chemical Residual Analysis, College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China

² The Key Lab of Analysis and Detection Technology for Food Safety of the MOE, State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou 350108, China

³ Department of Pharmaceutical Analysis, Faculty of Pharmacy, Fujian Medical University, Fuzhou 350108, China

Sensors 2017, 17(11), 2521; https://doi.org/10.3390/s17112521 - 2 Nov 2017

Cited by 29 | Viewed by 6621

Abstract

In this work, uniformly-dispersed platinum nanoparticles (PtNPs) were synthesized by a simple chemical reduction method, in which citric acid and sodium borohydride acted as a stabilizer and reducer, respectively. An ultrasensitive colorimetric sensor for the facile and rapid detection of Ag⁺ ions [...] Read more.

In this work, uniformly-dispersed platinum nanoparticles (PtNPs) were synthesized by a simple chemical reduction method, in which citric acid and sodium borohydride acted as a stabilizer and reducer, respectively. An ultrasensitive colorimetric sensor for the facile and rapid detection of Ag⁺ ions was constructed based on the peroxidase mimetic activities of the obtained PtNPs, which can catalyze the oxidation of 3,3’,5,5’-tetramethylbenzidine (TMB) by H₂O₂ to produce colored products. The introduced Ag⁺ would be reduced to Ag⁰ by the capped citric acid, and the deposition of Ag⁰ on the PtNPs surface, can effectively inhibit the peroxidase-mimetic activity of PtNPs. Through measuring the maximum absorption signal of oxidized TMB at 652 nm, ultra-low detection limits (7.8 pM) of Ag⁺ can be reached. In addition to such high sensitivity, the colorimetric assay also displays excellent selectivity for other ions of interest and shows great potential for the detection of Ag⁺ in real water samples. Full article

(This article belongs to the Special Issue Fluorescent Probes and Sensors)

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29 pages, 923 KiB

Open AccessArticle

Indoor Multipath Assisted Angle of Arrival Localization

by Stijn Wielandt

and Lieven De Strycker^*

Dramco Research Group, Faculty of Engineering Technology, Electronics, KU Leuven, Gebroeders De Smetstraat 1, 9000 Ghent, Belgium

Sensors 2017, 17(11), 2522; https://doi.org/10.3390/s17112522 - 2 Nov 2017

Cited by 76 | Viewed by 9660

Abstract

Indoor radio frequency positioning systems enable a broad range of location aware applications. However, the localization accuracy is often impaired by Non-Line-Of-Sight (NLOS) connections and indoor multipath effects. An interesting evolution in widely deployed communication systems is the transition to multi-antenna devices with [...] Read more.

Indoor radio frequency positioning systems enable a broad range of location aware applications. However, the localization accuracy is often impaired by Non-Line-Of-Sight (NLOS) connections and indoor multipath effects. An interesting evolution in widely deployed communication systems is the transition to multi-antenna devices with beamforming capabilities. These properties form an opportunity for localization methods based on Angle of Arrival (AoA) estimation. This work investigates how multipath propagation can be exploited to enhance the accuracy of AoA localization systems. The presented multipath assisted method resembles a fingerprinting approach, matching an AoA measurement vector to a set of reference vectors. However, reference data is not generated by labor intensive site surveying. Instead, a ray tracer is used, relying on a-priori known floor plan information. The resulting algorithm requires only one fixed receiving antenna array to determine the position of a mobile transmitter in a room. The approach is experimentally evaluated in LOS and NLOS conditions, providing insights in the accuracy and robustness. The measurements are performed in various indoor environments with different hardware configurations. This leads to the conclusion that the proposed system yields a considerable accuracy improvement over common narrowband AoA positioning methods, as well as a reduction of setup efforts in comparison to conventional fingerprinting systems. Full article

(This article belongs to the Special Issue Sensors and Sensing in Indoor Localization, Tracking, Navigation and Activity Monitoring)

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36 pages, 6967 KiB

Open AccessArticle

Design and Analysis of a Data Fusion Scheme in Mobile Wireless Sensor Networks Based on Multi-Protocol Mobile Agents

by Chunxue Wu¹, Wenliang Wu¹, Caihua Wan¹, Ernst Bekkering²

and Naixue Xiong^1,2,*

¹ School of Optical-Electrical & Computer Engineering, University of Shanghai for Science & Technology, Shanghai 200093, China

² Department of Mathematics and Computer Science, Northeastern State University, Tahlequah, OK 74464, USA

Sensors 2017, 17(11), 2523; https://doi.org/10.3390/s17112523 - 3 Nov 2017

Cited by 7 | Viewed by 4952

Abstract

Sensors are increasingly used in mobile environments with wireless network connections. Multiple sensor types measure distinct aspects of the same event. Their measurements are then combined to produce integrated, reliable results. As the number of sensors in networks increases, low energy requirements and [...] Read more.

Sensors are increasingly used in mobile environments with wireless network connections. Multiple sensor types measure distinct aspects of the same event. Their measurements are then combined to produce integrated, reliable results. As the number of sensors in networks increases, low energy requirements and changing network connections complicate event detection and measurement. We present a data fusion scheme for use in mobile wireless sensor networks with high energy efficiency and low network delays, that still produces reliable results. In the first phase, we used a network simulation where mobile agents dynamically select the next hop migration node based on the stability parameter of the link, and perform the data fusion at the migration node. Agents use the fusion results to decide if it should return the fusion results to the processing center or continue to collect more data. In the second phase. The feasibility of data fusion at the node level is confirmed by an experimental design where fused data from color sensors show near-identical results to actual physical temperatures. These results are potentially important for new large-scale sensor network applications. Full article

(This article belongs to the Special Issue Sensor Intelligent Data Analysis for Social Networks: Theory and Applications)

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23 pages, 6686 KiB

Open AccessArticle

Remaining Useful Life Estimation of Insulated Gate Biploar Transistors (IGBTs) Based on a Novel Volterra k-Nearest Neighbor Optimally Pruned Extreme Learning Machine (VKOPP) Model Using Degradation Data

by Zhen Liu^1,*

, Wenjuan Mei¹, Xianping Zeng², Chenglin Yang¹ and Xiuyun Zhou¹

¹ School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China

² Quanzhou Institute of Equipment Manufacturing, Haixi Institutes, Chinese Academy of Sciences, Quanzhou 362200, China

Sensors 2017, 17(11), 2524; https://doi.org/10.3390/s17112524 - 3 Nov 2017

Cited by 39 | Viewed by 6008

Abstract

The insulated gate bipolar transistor (IGBT) is a kind of excellent performance switching device used widely in power electronic systems. How to estimate the remaining useful life (RUL) of an IGBT to ensure the safety and reliability of the power electronics system is [...] Read more.

The insulated gate bipolar transistor (IGBT) is a kind of excellent performance switching device used widely in power electronic systems. How to estimate the remaining useful life (RUL) of an IGBT to ensure the safety and reliability of the power electronics system is currently a challenging issue in the field of IGBT reliability. The aim of this paper is to develop a prognostic technique for estimating IGBTs’ RUL. There is a need for an efficient prognostic algorithm that is able to support in-situ decision-making. In this paper, a novel prediction model with a complete structure based on optimally pruned extreme learning machine (OPELM) and Volterra series is proposed to track the IGBT’s degradation trace and estimate its RUL; we refer to this model as Volterra k-nearest neighbor OPELM prediction (VKOPP) model. This model uses the minimum entropy rate method and Volterra series to reconstruct phase space for IGBTs’ ageing samples, and a new weight update algorithm, which can effectively reduce the influence of the outliers and noises, is utilized to establish the VKOPP network; then a combination of the k-nearest neighbor method (KNN) and least squares estimation (LSE) method is used to calculate the output weights of OPELM and predict the RUL of the IGBT. The prognostic results show that the proposed approach can predict the RUL of IGBT modules with small error and achieve higher prediction precision and lower time cost than some classic prediction approaches. Full article

(This article belongs to the Special Issue Sensor Signal and Information Processing)

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18 pages, 2093 KiB

Open AccessArticle

A Middleware Solution for Wireless IoT Applications in Sparse Smart Cities

by Paolo Bellavista¹

, Carlo Giannelli^2,*

, Stefano Lanzone¹, Giulio Riberto³, Cesare Stefanelli³ and Mauro Tortonesi³

¹ DISI—Department of Computer Science and Engineering, University of Bologna, Bologna 40136, Italy

² DMI—Department of Mathematics and Computer Science, University of Ferrara, Ferrara 44122, Italy

³ DE—Engineering Department, University of Ferrara, Ferrara 44122, Italy

Sensors 2017, 17(11), 2525; https://doi.org/10.3390/s17112525 - 3 Nov 2017

Cited by 20 | Viewed by 5117

Abstract

The spread of off-the-shelf mobile devices equipped with multiple wireless interfaces together with sophisticated sensors is paving the way to novel wireless Internet of Things (IoT) environments, characterized by multi-hop infrastructure-less wireless networks where devices carried by users act as sensors/actuators as well [...] Read more.

The spread of off-the-shelf mobile devices equipped with multiple wireless interfaces together with sophisticated sensors is paving the way to novel wireless Internet of Things (IoT) environments, characterized by multi-hop infrastructure-less wireless networks where devices carried by users act as sensors/actuators as well as network nodes. In particular, the paper presents Real Ad-hoc Multi-hop Peer-to peer-Wireless IoT Application (RAMP-WIA), a novel solution that facilitates the development, deployment, and management of applications in sparse Smart City environments, characterized by users willing to collaborate by allowing new applications to be deployed on their smartphones to remotely monitor and control fixed/mobile devices. RAMP-WIA allows users to dynamically configure single-hop wireless links, to manage opportunistically multi-hop packet dispatching considering that the network topology (together with the availability of sensors and actuators) may abruptly change, to actuate reliably sensor nodes specifically considering that only part of them could be actually reachable in a timely manner, and to upgrade dynamically the nodes through over-the-air distribution of new software components. The paper also reports the performance of RAMP-WIA on simple but realistic cases of small-scale deployment scenarios with off-the-shelf Android smartphones and Raspberry Pi devices; these results show not only the feasibility and soundness of the proposed approach, but also the efficiency of the middleware implemented when deployed on real testbeds. Full article

(This article belongs to the Special Issue Next Generation Wireless Technologies for Internet of Things)

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9 pages, 3415 KiB

Open AccessArticle

Plasmonic Waveguide Coupled Ring Cavity for a Non-Resonant Type Refractive Index Sensor

by Soon-Hong Kwon

Department of Physics, Chung-Ang University, Seoul 06974, Korea

Sensors 2017, 17(11), 2526; https://doi.org/10.3390/s17112526 - 3 Nov 2017

Cited by 8 | Viewed by 5421

Abstract

Sensitive refractive index sensors with small footprints have been studied to allow the integration of a large number of sensors into a tiny chip for bio/chemical applications. In particular, resonant-type index sensors based on various micro/nanocavities, which use a resonant wavelength dependence on [...] Read more.

Sensitive refractive index sensors with small footprints have been studied to allow the integration of a large number of sensors into a tiny chip for bio/chemical applications. In particular, resonant-type index sensors based on various micro/nanocavities, which use a resonant wavelength dependence on the refractive index of the analyte, have been developed. However, the spectral linewidth of the resonance, which becomes the resolution limit, is considerably large in plasmonic cavities due to the large absorption loss of metals. Therefore, there is demand for a new type of plasmonic refractive index sensor that is not limited by the linewidth of the cavity. We propose a new type of plasmonic index sensors consisting of a channel waveguide and a ring cavity. Two emissions from the ring cavity in both directions of the waveguide couple with a reflection phase difference depending on the length of a closed right arm with a reflecting boundary. Therefore, the output power dramatically and sensitively changes as a function of the refractive index of the analyte filling the waveguide. Full article

(This article belongs to the Special Issue Surface Plasmon Resonance Sensing)

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19 pages, 2588 KiB

Open AccessArticle

Comparison of Measurement Models for 3D Magnetic Localization and Tracking

by Guido De Angelis^1,*

, Alessio De Angelis², Antonio Moschitta² and Paolo Carbone²

¹ Regione Umbria, 06124 Perugia, Italy

² Engineering Department, Università degli Studi di Perugia, 06125 Perugia, Italy

Sensors 2017, 17(11), 2527; https://doi.org/10.3390/s17112527 - 3 Nov 2017

Cited by 36 | Viewed by 5679

Abstract

In this paper, we consider magnetic positioning and tracking of objects and provide a comparison of the characteristics of two major measurement models: the magnetic dipole model and the mutual inductance model. The numerical results obtained by applying these models to a short-range [...] Read more.

In this paper, we consider magnetic positioning and tracking of objects and provide a comparison of the characteristics of two major measurement models: the magnetic dipole model and the mutual inductance model. The numerical results obtained by applying these models to a short-range position measurement application, with a maximum operating distance of approximately 50 cm, are compared. Based on the results of this comparison, a prototype 9-sensor array is developed, experimental tests are performed, and extensive measurement results are presented. Outcomes show the feasibility of tracking the position and orientation of a mobile coil in real time with a median positioning error below 1 cm and a worst-case error of about 2 cm and 11 degrees inside a spatial region of 30 × 30 × 30 cm³ operational volume. Full article

(This article belongs to the Special Issue Sensors and Sensing in Indoor Localization, Tracking, Navigation and Activity Monitoring)

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15 pages, 12201 KiB

Open AccessArticle

A High Sensitivity Preamplifier for Quartz Tuning Forks in QEPAS (Quartz Enhanced PhotoAcoustic Spectroscopy) Applications

by Tomasz Starecki and Piotr Z. Wieczorek^*

Institute of Electronic Systems, Warsaw University of Technology, Nowowiejska 15/19, 00-665 Warsaw, Poland

Sensors 2017, 17(11), 2528; https://doi.org/10.3390/s17112528 - 3 Nov 2017

Cited by 25 | Viewed by 8826

Abstract

All the preamplifiers dedicated for Quartz Enhanced PhotoAcoustic Spectroscopy (QEPAS) applications that have so far been reported in the literature have been based on operational amplifiers working in transimpedance configurations. Taking into consideration that QEPAS sensors are based on quartz tuning forks, and [...] Read more.

All the preamplifiers dedicated for Quartz Enhanced PhotoAcoustic Spectroscopy (QEPAS) applications that have so far been reported in the literature have been based on operational amplifiers working in transimpedance configurations. Taking into consideration that QEPAS sensors are based on quartz tuning forks, and that quartz has a relatively high voltage constant and relatively low charge constant, it seems that a transimpedance amplifier is not an optimal solution. This paper describes the design of a quartz QEPAS sensor preamplifier, implemented with voltage amplifier configuration. Discussion of an electrical model of the circuit and preliminary measurements are presented. Both theoretical analysis and experiments show that use of the voltage configuration allows for a substantial increase of the output signal in comparison to the transimpedance circuit with the same tuning fork working in identical conditions. Assuming that the sensitivity of the QEPAS technique depends directly on the properties of the preamplifier, use of the voltage amplifier configuration should result in an increase of QEPAS sensitivity by one to two orders of magnitude. Full article

(This article belongs to the Special Issue Piezoelectric Micro- and Nano-Devices)

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13 pages, 3316 KiB

Open AccessArticle

Long-Term Stability of Polymer-Coated Surface Transverse Wave Sensors for the Detection of Organic Solvent Vapors

by Ullrich Stahl^1,2

, Achim Voigt¹, Marian Dirschka¹, Nicole Barié¹, Christiane Richter¹, Ansgar Waldbaur¹, Friederike J. Gruhl¹, Bastian E. Rapp¹

, Michael Rapp¹ and Kerstin Länge^1,*

¹ Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany

² Faculty of Chemical Engineering, Central University of Ecuador, Calle Ritter s/n y Bolivia, 170521 Quito, Ecuador

Sensors 2017, 17(11), 2529; https://doi.org/10.3390/s17112529 - 3 Nov 2017

Cited by 19 | Viewed by 6108

Abstract

Arrays with polymer-coated acoustic sensors, such as surface acoustic wave (SAW) and surface transverse wave (STW) sensors, have successfully been applied for a variety of gas sensing applications. However, the stability of the sensors’ polymer coatings over a longer period of use has [...] Read more.

Arrays with polymer-coated acoustic sensors, such as surface acoustic wave (SAW) and surface transverse wave (STW) sensors, have successfully been applied for a variety of gas sensing applications. However, the stability of the sensors’ polymer coatings over a longer period of use has hardly been investigated. We used an array of eight STW resonator sensors coated with different polymers. This sensor array was used at semi-annual intervals for a three-year period to detect organic solvent vapors of three different chemical classes: a halogenated hydrocarbon (chloroform), an aliphatic hydrocarbon (octane), and an aromatic hydrocarbon (xylene). The sensor signals were evaluated with regard to absolute signal shifts and normalized signal shifts leading to signal patterns characteristic of the respective solvent vapors. No significant time-related changes of sensor signals or signal patterns were observed, i.e., the polymer coatings kept their performance during the course of the study. Therefore, the polymer-coated STW sensors proved to be robust devices which can be used for detecting organic solvent vapors both qualitatively and quantitatively for several years. Full article

(This article belongs to the Special Issue Surface Acoustic Wave and Bulk Acoustic Wave Sensors)

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16 pages, 3893 KiB

Open AccessArticle

Adaptive Sampling for Urban Air Quality through Participatory Sensing

by Yuanyuan Zeng^1,2,* and Kai Xiang^3,*

¹ Electronic Information School, Wuhan University, Wuhan 430072, China

² Collaborative Innovation Center for Geospatial Technology, Wuhan 430079, China

³ School of Information Management and Statistics, Hubei University of Economics, Wuhan 430205, China

Sensors 2017, 17(11), 2531; https://doi.org/10.3390/s17112531 - 3 Nov 2017

Cited by 17 | Viewed by 5803

Abstract

Air pollution is one of the major problems of the modern world. The popularization and powerful functions of smartphone applications enable people to participate in urban sensing to better know about the air problems surrounding them. Data sampling is one of the most [...] Read more.

Air pollution is one of the major problems of the modern world. The popularization and powerful functions of smartphone applications enable people to participate in urban sensing to better know about the air problems surrounding them. Data sampling is one of the most important problems that affect the sensing performance. In this paper, we propose an Adaptive Sampling Scheme for Urban Air Quality (AS-air) through participatory sensing. Firstly, we propose to find the pattern rules of air quality according to the historical data contributed by participants based on Apriori algorithm. Based on it, we predict the on-line air quality and use it to accelerate the learning process to choose and adapt the sampling parameter based on Q-learning. The evaluation results show that AS-air provides an energy-efficient sampling strategy, which is adaptive toward the varied outside air environment with good sampling efficiency. Full article

(This article belongs to the Special Issue Crowd-Sensing and Remote Sensing Technologies for Smart Cities)

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13 pages, 4720 KiB

Open AccessArticle

Towards the Development of a Low-Cost Device for the Detection of Explosives Vapors by Fluorescence Quenching of Conjugated Polymers in Solid Matrices

by Liliana M. Martelo^1,2,*

, Tiago F. Pimentel Das Neves³, João Figueiredo³, Lino Marques³

, Alexander Fedorov², Ana Charas⁴, Mário N. Berberan-Santos²

and Hugh D. Burrows¹

¹ Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal

² Centro de Química-Física Molecular (CQFM) and the Institute of Nanoscience and Nanotechnology (IN), Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal

³ Institute of Systems and Robotics (ISR), University of Coimbra, 3030-290 Coimbra, Portugal

⁴ Instituto de Telecomunicações, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal

Sensors 2017, 17(11), 2532; https://doi.org/10.3390/s17112532 - 3 Nov 2017

Cited by 12 | Viewed by 5302

Abstract

Conjugated polymers (CPs) have proved to be promising chemosensory materials for detecting nitroaromatic explosives vapors, as they quickly convert a chemical interaction into an easily-measured high-sensitivity optical output. The nitroaromatic analytes are strongly electron-deficient, whereas the conjugated polymer sensing materials are electron-rich. As [...] Read more.

Conjugated polymers (CPs) have proved to be promising chemosensory materials for detecting nitroaromatic explosives vapors, as they quickly convert a chemical interaction into an easily-measured high-sensitivity optical output. The nitroaromatic analytes are strongly electron-deficient, whereas the conjugated polymer sensing materials are electron-rich. As a result, the photoexcitation of the CP is followed by electron transfer to the nitroaromatic analyte, resulting in a quenching of the light-emission from the conjugated polymer. The best CP in our studies was found to be poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-bithiophene] (F8T2). It is photostable, has a good absorption between 400 and 450 nm, and a strong and structured fluorescence around 550 nm. Our studies indicate up to 96% quenching of light-emission, accompanied by a marked decrease in the fluorescence lifetime, upon exposure of the films of F8T2 in ethyl cellulose to nitrobenzene (NB) and 1,3-dinitrobenzene (DNB) vapors at room temperature. The effects of the polymeric matrix, plasticizer, and temperature have been studied, and the morphology of films determined by scanning electron microscopy (SEM) and confocal fluorescence microscopy. We have used ink jet printing to produce sensor films containing both sensor element and a fluorescence reference. In addition, a high dynamic range, intensity-based fluorometer, using a laser diode and a filtered photodiode was developed for use with this system. Full article

(This article belongs to the Special Issue Fluorescent Probes and Sensors)

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18 pages, 2424 KiB

Open AccessArticle

Loose Coupling of Wearable-Based INSs with Automatic Heading Evaluation

by Dina Bousdar Ahmed^*

and Estefania Munoz Diaz

Institute of Communications and Navigation, German Aerospace Centre (DLR), Oberpfaffenhofen, 82234 Wessling, Germany

Sensors 2017, 17(11), 2534; https://doi.org/10.3390/s17112534 - 3 Nov 2017

Cited by 9 | Viewed by 4665

Abstract

Position tracking of pedestrians by means of inertial sensors is a highly explored field of research. In fact, there are already many approaches to implement inertial navigation systems (INSs). However, most of them use a single inertial measurement unit (IMU) attached to the [...] Read more.

Position tracking of pedestrians by means of inertial sensors is a highly explored field of research. In fact, there are already many approaches to implement inertial navigation systems (INSs). However, most of them use a single inertial measurement unit (IMU) attached to the pedestrian’s body. Since wearable-devices will be given items in the future, this work explores the implementation of an INS using two wearable-based IMUs. A loosely coupled approach is proposed to combine the outputs of wearable-based INSs. The latter are based on a pocket-mounted IMU and a foot-mounted IMU. The loosely coupled fusion combines the output of the two INSs not only when these outputs are least erroneous, but also automatically favoring the best output. This approach is named smart update. The main challenge is determining the quality of the heading estimation of each INS, which changes every time. In order to address this, a novel concept to determine the quality of the heading estimation is presented. This concept is subject to a patent application. The results show that the position error rate of the loosely coupled fusion is 10 cm/s better than either the foot INS’s or pocket INS’s error rate in 95% of the cases. Full article

(This article belongs to the Special Issue Inertial Sensors for Positioning and Navigation)

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16 pages, 3316 KiB

Open AccessArticle

Design of UAV-Embedded Microphone Array System for Sound Source Localization in Outdoor Environments

by Kotaro Hoshiba^1,*, Kai Washizaki², Mizuho Wakabayashi², Takahiro Ishiki^2,‡, Makoto Kumon²

, Yoshiaki Bando³, Daniel Gabriel¹, Kazuhiro Nakadai^1,4 and Hiroshi G. Okuno⁵

¹ Department of Systems and Control Engineering, School of Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan

² Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan

³ Graduate School of Informatics, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan

⁴ Honda Research Institute Japan Co., Ltd., 8-1 Honcho, Wako, Saitama 351-0188, Japan

⁵ Graduate Program for Embodiment Informatics, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan

^‡ Current address: LIXIL Corporation, 2-1-1 Ojima, Koto-ku, Tokyo 136-8535, Japan.

Sensors 2017, 17(11), 2535; https://doi.org/10.3390/s17112535 - 3 Nov 2017

Cited by 107 | Viewed by 14616

Abstract

In search and rescue activities, unmanned aerial vehicles (UAV) should exploit sound information to compensate for poor visual information. This paper describes the design and implementation of a UAV-embedded microphone array system for sound source localization in outdoor environments. Four critical development problems [...] Read more.

In search and rescue activities, unmanned aerial vehicles (UAV) should exploit sound information to compensate for poor visual information. This paper describes the design and implementation of a UAV-embedded microphone array system for sound source localization in outdoor environments. Four critical development problems included water-resistance of the microphone array, efficiency in assembling, reliability of wireless communication, and sufficiency of visualization tools for operators. To solve these problems, we developed a spherical microphone array system (SMAS) consisting of a microphone array, a stable wireless network communication system, and intuitive visualization tools. The performance of SMAS was evaluated with simulated data and a demonstration in the field. Results confirmed that the SMAS provides highly accurate localization, water resistance, prompt assembly, stable wireless communication, and intuitive information for observers and operators. Full article

(This article belongs to the Special Issue UAV or Drones for Remote Sensing Applications)

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17 pages, 4257 KiB

Open AccessArticle

All-Solid-State Sodium-Selective Electrode with a Solid Contact of Chitosan/Prussian Blue Nanocomposite

by Tanushree Ghosh^1,2,3, Hyun-Joong Chung^1,*

and Jana Rieger^2,3,*

¹ Department of Chemical and Materials Engineering, Faculty of Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada

² The Institute for Reconstructive Sciences in Medicine (iRSM), Misericordia Community Hospital, Edmonton, AB T5R 4H5, Canada

³ Department of Communication Sciences and Disorders, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB T6G 2G4, Canada

Sensors 2017, 17(11), 2536; https://doi.org/10.3390/s17112536 - 3 Nov 2017

Cited by 31 | Viewed by 9804

Abstract

Conventional ion-selective electrodes with a liquid junction have the disadvantage of potential drift. All-solid-state ion-selective electrodes with solid contact in between the metal electrode and the ion-selective membrane offer high capacitance or conductance to enhance potential stability. Solution-casted chitosan/Prussian blue nanocomposite (ChPBN) was [...] Read more.

Conventional ion-selective electrodes with a liquid junction have the disadvantage of potential drift. All-solid-state ion-selective electrodes with solid contact in between the metal electrode and the ion-selective membrane offer high capacitance or conductance to enhance potential stability. Solution-casted chitosan/Prussian blue nanocomposite (ChPBN) was employed as the solid contact layer for an all-solid-state sodium ion-selective electrode in a potentiometric sodium ion sensor. Morphological and chemical analyses confirmed that the ChPBN is a macroporous network of chitosan that contains abundant Prussian blue nanoparticles. Situated between a screen-printed carbon electrode and a sodium-ionophore-filled polyvinylchloride ion-selective membrane, the ChPBN layer exhibited high redox capacitance and fast charge transfer capability, which significantly enhanced the performance of the sodium ion-selective electrode. A good Nernstian response with a slope of 52.4 mV/decade in the linear range from 10⁻⁴–1 M of NaCl was observed. The stability of the electrical potential of the new solid contact was tested by chronopotentiometry, and the capacitance of the electrode was 154 ± 4 µF. The response stability in terms of potential drift was excellent (1.3 µV/h) for 20 h of continuous measurement. The ChPBN proved to be an efficient solid contact to enhance the potential stability of the all-solid-state ion-selective electrode. Full article

(This article belongs to the Special Issue Smart Sensing System for Real-Time Monitoring)

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16 pages, 3019 KiB

Open AccessArticle

Maize Cropping Systems Mapping Using RapidEye Observations in Agro-Ecological Landscapes in Kenya

by Kyalo Richard¹, Elfatih M. Abdel-Rahman^1,2, Sevgan Subramanian¹, Johnson O. Nyasani^1,3, Michael Thiel⁴, Hosein Jozani⁴, Christian Borgemeister⁵ and Tobias Landmann^1,*

¹ International Center for Insect Physiology and Ecology (ICIPE), P.O. Box 30772, 00100 Nairobi, Kenya

² Department of Agronomy, Faculty of Agriculture, University of Khartoum, Khartoum North 13314, Sudan

³ Crop Health Unit, Kenya Agricultural and Livestock Research Organization, Embu Research Centre, P.O. Box 27, 60100 Embu, Kenya

⁴ Department of Remote Sensing, University of Würzburg, Oswald-Külpe-Weg 86, 97074 Würzburg, Germany

⁵ Center for Development Research (ZEF), Department of Ecology and Natural Resources Management, University of Bonn, Walter-Flex-Str. 3, 53113 Bonn, Germany

Sensors 2017, 17(11), 2537; https://doi.org/10.3390/s17112537 - 3 Nov 2017

Cited by 30 | Viewed by 6767

Abstract

Cropping systems information on explicit scales is an important but rarely available variable in many crops modeling routines and of utmost importance for understanding pests and disease propagation mechanisms in agro-ecological landscapes. In this study, high spatial and temporal resolution RapidEye bio-temporal data [...] Read more.

Cropping systems information on explicit scales is an important but rarely available variable in many crops modeling routines and of utmost importance for understanding pests and disease propagation mechanisms in agro-ecological landscapes. In this study, high spatial and temporal resolution RapidEye bio-temporal data were utilized within a novel 2-step hierarchical random forest (RF) classification approach to map areas of mono- and mixed maize cropping systems. A small-scale maize farming site in Machakos County, Kenya was used as a study site. Within the study site, field data was collected during the satellite acquisition period on general land use/land cover (LULC) and the two cropping systems. Firstly, non-cropland areas were masked out from other land use/land cover using the LULC mapping result. Subsequently an optimized RF model was applied to the cropland layer to map the two cropping systems (2nd classification step). An overall accuracy of 93% was attained for the LULC classification, while the class accuracies (PA: producer’s accuracy and UA: user’s accuracy) for the two cropping systems were consistently above 85%. We concluded that explicit mapping of different cropping systems is feasible in complex and highly fragmented agro-ecological landscapes if high resolution and multi-temporal satellite data such as 5 m RapidEye data is employed. Further research is needed on the feasibility of using freely available 10–20 m Sentinel-2 data for wide-area assessment of cropping systems as an important variable in numerous crop productivity models. Full article

(This article belongs to the Section Remote Sensors)

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15 pages, 4097 KiB

Open AccessArticle

New ZnO-Based Glass Ceramic Sensor for H₂ and NO₂ Detection

by Mohamed Hassan¹

, Ahmed S. Afify²

, Mohamed Ataalla³, Daniel Milanese⁴

and Jean-Marc Tulliani^2,*

¹ High Institute for Engineering & Technology, 21 K Cairo-Belbeis Rd, Al-Obour 11828, Egypt

² INSTM R.U PoliTO-LINCE Laboratory, Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy

³ Faculty of Engineering and Technology, Badr University in Cairo (BUC), Badr 11829, Egypt

⁴ Department of Applied Science and Technology, Politecnico di Torino, 10129 Torino, Italy

Sensors 2017, 17(11), 2538; https://doi.org/10.3390/s17112538 - 3 Nov 2017

Cited by 8 | Viewed by 5744

Abstract

In this study, a glass ceramic with a nominal composition 58ZnO:4Bi₂O₃:4WO₃:33.3B₂O₃ was synthesized by melt quenching technique. A gas sensor was then manufactured using a ZnO sol-gel phase as a permanent binder of the [...] Read more.

In this study, a glass ceramic with a nominal composition 58ZnO:4Bi₂O₃:4WO₃:33.3B₂O₃ was synthesized by melt quenching technique. A gas sensor was then manufactured using a ZnO sol-gel phase as a permanent binder of the glass–ceramic to an alumina substrate having interdigitated electrodes. The film sensitivity towards humidity, NH₃, H₂ and NO₂ was studied at different temperatures. X-ray diffraction technique (XRD), field emission- scanning electron microscopy (FE-SEM) and differential thermal analysis (DTA) were used to characterize the prepared material. Though the response in the sub-ppm NO₂ concentration range was not explored, the observed results are comparable with the latest found in the literature. Full article

(This article belongs to the Special Issue Gas Sensors based on Semiconducting Metal Oxides)

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20 pages, 3164 KiB

Open AccessArticle

Design Optimisation of a Magnetic Field Based Soft Tactile Sensor

by Gregory de Boer^1,*

, Nicholas Raske²

, Hongbo Wang³

, Junwai Kow¹, Ali Alazmani¹

, Mazdak Ghajari⁴

, Peter Culmer¹

and Robert Hewson²

¹ School of Mechanical Engineering, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK

² Department of Aeronautics, Imperial College London, South Kensington Campus, London SW7 2AZ, UK

³ Center for Micro-BioRobotics, Istituto Italiano di Tecnologia, Viale Rinaldo Piaggio 34, 56025 Pontedera, Italy

⁴ Dyson School of Design Engineering, Imperial College London, 10 Princes Gardens, Kensington Princes Gardens, London SW7 1NA, UK

Sensors 2017, 17(11), 2539; https://doi.org/10.3390/s17112539 - 3 Nov 2017

Cited by 24 | Viewed by 7503

Abstract

This paper investigates the design optimisation of a magnetic field based soft tactile sensor, comprised of a magnet and Hall effect module separated by an elastomer. The aim was to minimise sensitivity of the output force with respect to the input magnetic field; [...] Read more.

This paper investigates the design optimisation of a magnetic field based soft tactile sensor, comprised of a magnet and Hall effect module separated by an elastomer. The aim was to minimise sensitivity of the output force with respect to the input magnetic field; this was achieved by varying the geometry and material properties. Finite element simulations determined the magnetic field and structural behaviour under load. Genetic programming produced phenomenological expressions describing these responses. Optimisation studies constrained by a measurable force and stable loading conditions were conducted; these produced Pareto sets of designs from which the optimal sensor characteristics were selected. The optimisation demonstrated a compromise between sensitivity and the measurable force, a fabricated version of the optimised sensor validated the improvements made using this methodology. The approach presented can be applied in general for optimising soft tactile sensor designs over a range of applications and sensing modes. Full article

(This article belongs to the Special Issue Tactile Sensors and Sensing)

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14 pages, 6157 KiB

Open AccessArticle

Improved Durability and Sensitivity of Bitterness-Sensing Membrane for Medicines

by Xiao Wu^1,*, Hideya Onitake¹, Zhiqin Huang¹, Takeshi Shiino¹, Yusuke Tahara², Rui Yatabe², Hidekazu Ikezaki³ and Kiyoshi Toko^1,2

¹ Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan

² Research and Development Center for Taste and Odor Sensing, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan

³ Intelligent Sensor Technology, Inc., 5-1-1 Onna, Atsugi-shi, Kanagawa 243-0032, Japan

Sensors 2017, 17(11), 2541; https://doi.org/10.3390/s17112541 - 4 Nov 2017

Cited by 14 | Viewed by 4899

Abstract

This paper reports the improvement of a bitterness sensor based on a lipid polymer membrane consisting of phosphoric acid di-n-decyl ester (PADE) as a lipid and bis(1-butylpentyl) adipate (BBPA) and tributyl o-acetylcitrate (TBAC) as plasticizers. Although the commercialized bitterness sensor (BT0) has high [...] Read more.

This paper reports the improvement of a bitterness sensor based on a lipid polymer membrane consisting of phosphoric acid di-n-decyl ester (PADE) as a lipid and bis(1-butylpentyl) adipate (BBPA) and tributyl o-acetylcitrate (TBAC) as plasticizers. Although the commercialized bitterness sensor (BT0) has high sensitivity and selectivity to the bitterness of medicines, the sensor response gradually decreases to almost zero after two years at room temperature and humidity in a laboratory. To reveal the reason for the deterioration of the response, we investigated sensor membranes by measuring the membrane potential, contact angle, and adsorption amount, as well as by performing gas chromatography-mass spectrometry (GC-MS), liquid chromatography-tandem mass spectrometry (LC-MS/MS). We found that the change in the surface charge density caused by the hydrolysis of TBAC led to the deterioration of the response. The acidic environment generated by PADE promoted TBAC hydrolysis. Finally, we succeeded in fabricating a new membrane for sensing the bitterness of medicines with higher durability and sensitivity by adjusting the proportions of the lipid and plasticizers. Full article

(This article belongs to the Special Issue Electronic Tongues and Electronic Noses)

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13 pages, 4687 KiB

Open AccessArticle

Structural Health Monitoring of Above-Ground Storage Tank Floors by Ultrasonic Guided Wave Excitation on the Tank Wall

by Premesh S. Lowe^1,*

, Wenbo Duan¹

, Jamil Kanfoud¹ and Tat-Hean Gan^1,2,*

¹ Brunel Innovation Centre (BIC), Granta Park, Great Abington, Cambridgeshire CB21 6AL, UK

² TWI Ltd., Granta Park, Great Abington, Cambridgeshire CB21 6AL, UK

Sensors 2017, 17(11), 2542; https://doi.org/10.3390/s17112542 - 4 Nov 2017

Cited by 20 | Viewed by 7558

Abstract

There is an increasing interest in using ultrasonic guided waves to assess the structural degradation of above-ground storage tank floors. This is a non-invasive and economically viable means of assessing structural degradation. Above-ground storage tank floors are ageing assets which need to be [...] Read more.

There is an increasing interest in using ultrasonic guided waves to assess the structural degradation of above-ground storage tank floors. This is a non-invasive and economically viable means of assessing structural degradation. Above-ground storage tank floors are ageing assets which need to be inspected periodically to avoid structural failure. At present, normal-stress type transducers are bonded to the tank annular chime to generate a force field in the thickness direction of the floor and excite fundamental symmetric and asymmetric Lamb modes. However, the majority of above-ground storage tanks in use have no annular chime due to a simplified design and/or have a degraded chime due to corrosion. This means that transducers cannot be mounted on the chime to assess structural health according to the present technology, and the market share of structural health monitoring of above-ground storage tank floors using ultrasonic guided wave is thus limited. Therefore, the present study investigates the potential of using the tank wall to bond the transducer instead of the tank annular chime. Both normal and shear type transducers were investigated numerically, and results were validated using a 4.1 m diameter above-ground storage tank. The study results show shear mode type transducers bonded to the tank wall can be used to assess the structural health of the above-ground tank floors using an ultrasonic guided wave. It is also shown that for the cases studied there is a 7.4 dB signal-to-noise ratio improvement at 45 kHz for the guided wave excitation on the tank wall using shear mode transducers. Full article

(This article belongs to the Special Issue Novel Methodologies to Interpret Non-Destructive Testing and Structural Health Monitoring Data)

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8 pages, 13175 KiB

Open AccessArticle

An FBG Optical Approach to Thermal Expansion Measurements under Hydrostatic Pressure

by Priscila F. S. Rosa^1,*, Sean M. Thomas¹, Fedor F. Balakirev², Jon Betts², Soonbeom Seo¹

, Eric D. Bauer¹, Joe D. Thompson¹ and Marcelo Jaime^2,3

¹ Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, MS K764, Los Alamos, NM 87545, USA

² National High Magnetic Field Laboratory, Los Alamos National Laboratory, MS E536, Los Alamos, NM 87545, USA

³ Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, NM 87545, USA

Sensors 2017, 17(11), 2543; https://doi.org/10.3390/s17112543 - 4 Nov 2017

Cited by 10 | Viewed by 4698

Abstract

We report on an optical technique for measuring thermal expansion and magnetostriction at cryogenic temperatures and under applied hydrostatic pressures of 2.0 GPa. Optical fiber Bragg gratings inside a clamp-type pressure chamber are used to measure the strain in a millimeter-sized sample of [...] Read more.

We report on an optical technique for measuring thermal expansion and magnetostriction at cryogenic temperatures and under applied hydrostatic pressures of 2.0 GPa. Optical fiber Bragg gratings inside a clamp-type pressure chamber are used to measure the strain in a millimeter-sized sample of CeRhIn₅. We describe the simultaneous measurement of two Bragg gratings in a single optical fiber using an optical sensing instrument capable of resolving changes in length [dL/L = (L− L₀)/L₀] on the order of 10⁻⁷. Our results demonstrate the possibility of performing high-resolution thermal expansion measurements under hydrostatic pressure, a capability previously hindered by the small working volumes typical of pressure cells. Full article

(This article belongs to the Special Issue Fiber Bragg Grating Based Sensors)

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10 pages, 2106 KiB

Open AccessArticle

Characterization and Differentiation of Petroleum-Derived Products by E-Nose Fingerprints

by Marta Ferreiro-González¹

, Gerardo F. Barbero¹

, Miguel Palma^1,*, Jesús Ayuso², José A. Álvarez² and Carmelo G. Barroso¹

¹ Department of Analytical Chemistry, Faculty of Sciences, IVAGRO, University of Cadiz, 11510 Puerto Real, Cádiz, Spain

² Department of Physical Chemistry, Faculty of Sciences, University of Cadiz, 11510 Puerto Real, Cádiz, Spain

Sensors 2017, 17(11), 2544; https://doi.org/10.3390/s17112544 - 5 Nov 2017

Cited by 23 | Viewed by 5010

Abstract

Characterization of petroleum-derived products is an area of continuing importance in environmental science, mainly related to fuel spills. In this study, a non-separative analytical method based on E-Nose (Electronic Nose) is presented as a rapid alternative for the characterization of several different petroleum-derived [...] Read more.

Characterization of petroleum-derived products is an area of continuing importance in environmental science, mainly related to fuel spills. In this study, a non-separative analytical method based on E-Nose (Electronic Nose) is presented as a rapid alternative for the characterization of several different petroleum-derived products including gasoline, diesel, aromatic solvents, and ethanol samples, which were poured onto different surfaces (wood, cork, and cotton). The working conditions about the headspace generation were 145 °C and 10 min. Mass spectroscopic data (45–200 m/z) combined with chemometric tools such as hierarchical cluster analysis (HCA), later principal component analysis (PCA), and finally linear discriminant analysis (LDA) allowed for a full discrimination of the samples. A characteristic fingerprint for each product can be used for discrimination or identification. The E-Nose can be considered as a green technique, and it is rapid and easy to use in routine analysis, thus providing a good alternative to currently used methods. Full article

(This article belongs to the Special Issue Electronic Tongues and Electronic Noses)

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25 pages, 6494 KiB

Open AccessArticle

An Ontology-Based Reasoning Framework for Querying Satellite Images for Disaster Monitoring

by Marjan Alirezaie^*, Andrey Kiselev

, Martin Längkvist

, Franziska Klügl and Amy Loutfi

Center for Applied Autonomous Sensor Systems, Örebro University, 702 81 Örebro, Sweden

Sensors 2017, 17(11), 2545; https://doi.org/10.3390/s17112545 - 5 Nov 2017

Cited by 31 | Viewed by 5908

Abstract

This paper presents a framework in which satellite images are classified and augmented with additional semantic information to enable queries about what can be found on the map at a particular location, but also about paths that can be taken. This is achieved [...] Read more.

This paper presents a framework in which satellite images are classified and augmented with additional semantic information to enable queries about what can be found on the map at a particular location, but also about paths that can be taken. This is achieved by a reasoning framework based on qualitative spatial reasoning that is able to find answers to high level queries that may vary on the current situation. This framework called SemCityMap, provides the full pipeline from enriching the raw image data with rudimentary labels to the integration of a knowledge representation and reasoning methods to user interfaces for high level querying. To illustrate the utility of SemCityMap in a disaster scenario, we use an urban environment—central Stockholm—in combination with a flood simulation. We show that the system provides useful answers to high-level queries also with respect to the current flood status. Examples of such queries concern path planning for vehicles or retrieval of safe regions such as “find all regions close to schools and far from the flooded area”. The particular advantage of our approach lies in the fact that ontological information and reasoning is explicitly integrated so that queries can be formulated in a natural way using concepts on appropriate level of abstraction, including additional constraints. Full article

(This article belongs to the Special Issue Remote Sensing and GIS for Geo-Hazards and Disasters)

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16 pages, 2712 KiB

Open AccessArticle

Centralized Multi-Sensor Square Root Cubature Joint Probabilistic Data Association

by Yu Liu^1,2,*

, Jun Liu^2,*, Gang Li³, Lin Qi², Yaowen Li³ and You He²

¹ School of Electronic and Information Engineering, Beihang University, Beijing 100191, China

² Research Institute of Information Fusion, Naval Aeronautical and Astronautical University, Yantai 264001, China

³ Department of Electronic Engineering, Tsinghua University, Beijing 100084, China

Sensors 2017, 17(11), 2546; https://doi.org/10.3390/s17112546 - 5 Nov 2017

Cited by 12 | Viewed by 4317

Abstract

This paper focuses on the tracking problem of multiple targets with multiple sensors in a nonlinear cluttered environment. To avoid Jacobian matrix computation and scaling parameter adjustment, improve numerical stability, and acquire more accurate estimated results for centralized nonlinear tracking, a novel centralized [...] Read more.

This paper focuses on the tracking problem of multiple targets with multiple sensors in a nonlinear cluttered environment. To avoid Jacobian matrix computation and scaling parameter adjustment, improve numerical stability, and acquire more accurate estimated results for centralized nonlinear tracking, a novel centralized multi-sensor square root cubature joint probabilistic data association algorithm (CMSCJPDA) is proposed. Firstly, the multi-sensor tracking problem is decomposed into several single-sensor multi-target tracking problems, which are sequentially processed during the estimation. Then, in each sensor, the assignment of its measurements to target tracks is accomplished on the basis of joint probabilistic data association (JPDA), and a weighted probability fusion method with square root version of a cubature Kalman filter (SRCKF) is utilized to estimate the targets’ state. With the measurements in all sensors processed CMSCJPDA is derived and the global estimated state is achieved. Experimental results show that CMSCJPDA is superior to the state-of-the-art algorithms in the aspects of tracking accuracy, numerical stability, and computational cost, which provides a new idea to solve multi-sensor tracking problems. Full article

(This article belongs to the Special Issue Advances in Multi-Sensor Information Fusion: Theory and Applications 2017)

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27 pages, 876 KiB

Open AccessArticle

Integrated Evaluation of Reliability and Power Consumption of Wireless Sensor Networks

by Antônio Dâmaso, Nelson Rosa^*

and Paulo Maciel

Centro de Informática, Universidade Federal de Pernambuco, Av. Jornalista Aníbal Fernandes, s/n-Cidade Universitária, 50740-560 Recife, PE, Brazil

Sensors 2017, 17(11), 2547; https://doi.org/10.3390/s17112547 - 5 Nov 2017

Cited by 23 | Viewed by 4668

Abstract

Power consumption is a primary interest in Wireless Sensor Networks (WSNs), and a large number of strategies have been proposed to evaluate it. However, those approaches usually neither consider reliability issues nor the power consumption of applications executing in the network. A central [...] Read more.

Power consumption is a primary interest in Wireless Sensor Networks (WSNs), and a large number of strategies have been proposed to evaluate it. However, those approaches usually neither consider reliability issues nor the power consumption of applications executing in the network. A central concern is the lack of consolidated solutions that enable us to evaluate the power consumption of applications and the network stack also considering their reliabilities. To solve this problem, we introduce a fully automatic solution to design power consumption aware WSN applications and communication protocols. The solution presented in this paper comprises a methodology to evaluate the power consumption based on the integration of formal models, a set of power consumption and reliability models, a sensitivity analysis strategy to select WSN configurations and a toolbox named EDEN to fully support the proposed methodology. This solution allows accurately estimating the power consumption of WSN applications and the network stack in an automated way. Full article

(This article belongs to the Section Sensor Networks)

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12 pages, 1627 KiB

Open AccessCommunication

Synergy Effect of Combining Fluorescence and Mid Infrared Fiber Spectroscopy for Kidney Tumor Diagnostics

by Andrey Bogomolov^1,2

, Valeria Belikova², Urszula J. Zabarylo³, Olga Bibikova^1,4,*, Iskander Usenov^1,5, Tatiana Sakharova¹, Hans Krause⁶

, Olaf Minet³, Elena Feliksberger¹ and Viacheslav Artyushenko¹

¹ art photonics GmbH, Rudower Chaussee 46, Berlin 12489, Germany

² Laboratory of Multivariate Analysis and Global Modeling, Samara State Technical University, Molodogvardeyskaya 244, 443100 Samara, Russia

³ Medical Physics & Optical Diagnostics, CC6 Campus Benjamin Franklin, Charité Universitätsmedizin Berlin, Hindenburgdamm 30, 12203 Berlin, Germany

⁴ Research-Educational Institute of Optics and Biophotonics, Saratov National Research State University, Saratov 410012, Russia

⁵ Technical University of Berlin, Institute of Optics and Atomic Physics, Berlin 10623, Germany

⁶ Deptartment of Urology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany

Sensors 2017, 17(11), 2548; https://doi.org/10.3390/s17112548 - 5 Nov 2017

Cited by 18 | Viewed by 5482

Abstract

Matching pairs of tumor and non-tumor kidney tissue samples of four patients were investigated ex vivo using a combination of two methods, attenuated total reflection mid infrared spectroscopy and fluorescence spectroscopy, through respectively prepared and adjusted fiber probes. In order to increase the [...] Read more.

Matching pairs of tumor and non-tumor kidney tissue samples of four patients were investigated ex vivo using a combination of two methods, attenuated total reflection mid infrared spectroscopy and fluorescence spectroscopy, through respectively prepared and adjusted fiber probes. In order to increase the data information content, the measurements on tissue samples in both methods were performed in the same 31 preselected positions. Multivariate data analysis revealed a synergic effect of combining the two methods for the diagnostics of kidney tumor compared to individual techniques. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Germany)

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13 pages, 4007 KiB

Open AccessArticle

Dimension-Factorized Range Migration Algorithm for Regularly Distributed Array Imaging

by Qijia Guo¹, Jie Wang¹, Tianying Chang^1,2,*

and Hong-Liang Cui^1,3

¹ College of Instrumentation & Electrical Engineering, Jilin University, Changchun 130061, China

² Institute of Automation, Shandong Academy of Sciences, Jinan 250014, China

³ Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China

Sensors 2017, 17(11), 2549; https://doi.org/10.3390/s17112549 - 5 Nov 2017

Cited by 6 | Viewed by 4389

Abstract

The two-dimensional planar MIMO array is a popular approach for millimeter wave imaging applications. As a promising practical alternative, sparse MIMO arrays have been devised to reduce the number of antenna elements and transmitting/receiving channels with predictable and acceptable loss in image quality. [...] Read more.

The two-dimensional planar MIMO array is a popular approach for millimeter wave imaging applications. As a promising practical alternative, sparse MIMO arrays have been devised to reduce the number of antenna elements and transmitting/receiving channels with predictable and acceptable loss in image quality. In this paper, a high precision three-dimensional imaging algorithm is proposed for MIMO arrays of the regularly distributed type, especially the sparse varieties. Termed the Dimension-Factorized Range Migration Algorithm, the new imaging approach factorizes the conventional MIMO Range Migration Algorithm into multiple operations across the sparse dimensions. The thinner the sparse dimensions of the array, the more efficient the new algorithm will be. Advantages of the proposed approach are demonstrated by comparison with the conventional MIMO Range Migration Algorithm and its non-uniform fast Fourier transform based variant in terms of all the important characteristics of the approaches, especially the anti-noise capability. The computation cost is analyzed as well to evaluate the efficiency quantitatively. Full article

(This article belongs to the Special Issue Sensor Signal and Information Processing)

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15 pages, 586 KiB

Open AccessArticle

Coverage Probability and Area Spectral Efficiency of Clustered Linear Unmanned Vehicle Sensor Networks

by Haejoon Jung¹

and In-Ho Lee^2,*

¹ Department of Information and Telecommunication Engineering, Incheon National University, Incheon 22012, Korea

² Department of Electrical, Electronic and Control Engineering, Hankyong National University, Anseong 17579, Korea

Sensors 2017, 17(11), 2550; https://doi.org/10.3390/s17112550 - 5 Nov 2017

Cited by 6 | Viewed by 4392

Abstract

In this paper, we consider clustered unmanned vehicle (UV) sensor networks for swarm sensing applications in a linear structure such as highway, tunnel, underwater pipelines, power lines, and international border. We assume that the linear UV sensor networks follow Thomas cluster process (TCP), [...] Read more.

In this paper, we consider clustered unmanned vehicle (UV) sensor networks for swarm sensing applications in a linear structure such as highway, tunnel, underwater pipelines, power lines, and international border. We assume that the linear UV sensor networks follow Thomas cluster process (TCP), in which the cluster locations are modelled by Poisson point process (PPP), while the cluster members (UVs) are normally distributed around their cluster centers. We focus on communications between UVs within a cluster such as local sensing data transfer or swarm coordination, where multiple UV pairs can share the same frequency band simultaneously. Thus, in the presence of co-channel interference both from the same cluster and the other clusters, we study the coverage and area spectral efficiency of the clustered UV sensor networks in a linear topology. Full article

(This article belongs to the Special Issue Sensor Networks for Smart Roads)

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14 pages, 4783 KiB

Open AccessArticle

An Energy Efficient Adaptive Sampling Algorithm in a Sensor Network for Automated Water Quality Monitoring

by Tongxin Shu^1,*, Min Xia², Jiahong Chen² and Clarence De Silva²

¹ Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC V6T 1Z4, Canada

² Department of Mechanical Engineering, University of British Columbia, Vancouver, BC V6T 1Z4, Canada

Sensors 2017, 17(11), 2551; https://doi.org/10.3390/s17112551 - 5 Nov 2017

Cited by 41 | Viewed by 6000

Abstract

Power management is crucial in the monitoring of a remote environment, especially when long-term monitoring is needed. Renewable energy sources such as solar and wind may be harvested to sustain a monitoring system. However, without proper power management, equipment within the monitoring system [...] Read more.

Power management is crucial in the monitoring of a remote environment, especially when long-term monitoring is needed. Renewable energy sources such as solar and wind may be harvested to sustain a monitoring system. However, without proper power management, equipment within the monitoring system may become nonfunctional and, as a consequence, the data or events captured during the monitoring process will become inaccurate as well. This paper develops and applies a novel adaptive sampling algorithm for power management in the automated monitoring of the quality of water in an extensive and remote aquatic environment. Based on the data collected on line using sensor nodes, a data-driven adaptive sampling algorithm (DDASA) is developed for improving the power efficiency while ensuring the accuracy of sampled data. The developed algorithm is evaluated using two distinct key parameters, which are dissolved oxygen (DO) and turbidity. It is found that by dynamically changing the sampling frequency, the battery lifetime can be effectively prolonged while maintaining a required level of sampling accuracy. According to the simulation results, compared to a fixed sampling rate, approximately 30.66% of the battery energy can be saved for three months of continuous water quality monitoring. Using the same dataset to compare with a traditional adaptive sampling algorithm (ASA), while achieving around the same Normalized Mean Error (NME), DDASA is superior in saving 5.31% more battery energy. Full article

(This article belongs to the Section Sensor Networks)

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11 pages, 2288 KiB

Open AccessArticle

Detonation Velocity Measurement with Chirped Fiber Bragg Grating

by Peng Wei

, Hao Lang^*

, Taolin Liu and Dong Xia

School of Instrument Science and Opto-Electronics Technology, Beihang University, Beijing 100191, China

Sensors 2017, 17(11), 2552; https://doi.org/10.3390/s17112552 - 6 Nov 2017

Cited by 26 | Viewed by 5112

Abstract

Detonation velocity is an important parameter for explosive, and it is crucial for many fields such as dynamic chemistry burn models, detonation propagation prediction, explosive performance estimation, and so on. Dual-channel detonation velocity measurement method and system are described. The CFBG sensors are [...] Read more.

Detonation velocity is an important parameter for explosive, and it is crucial for many fields such as dynamic chemistry burn models, detonation propagation prediction, explosive performance estimation, and so on. Dual-channel detonation velocity measurement method and system are described. The CFBG sensors are pasted both on the surface and in the center of the explosive cylinder. The length of CFBG sensors is measured via the hot-tip probe method. The light intensity reflected from the CFBG sensors attached to the explosive is transformed to voltage, and the voltage–time is then measured with the oscilloscope. According to the five experiments results, the relative standard uncertainty of detonation velocity is below 1%. Full article

(This article belongs to the Special Issue Fiber Bragg Grating Based Sensors)

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24 pages, 1720 KiB

Open AccessArticle

Efficient Graph-Based Resource Allocation Scheme Using Maximal Independent Set for Randomly- Deployed Small Star Networks

by Jian Zhou¹, Lusheng Wang^1,*, Weidong Wang² and Qingfeng Zhou¹

¹ School of Computer and Information, Hefei University of Technology, Hefei 230009, China

² Key Laboratory of Universal Wireless Communications (Beijing University of Posts and Telecommunications), Ministry of Education, Beijing 100876, China

Sensors 2017, 17(11), 2553; https://doi.org/10.3390/s17112553 - 6 Nov 2017

Cited by 7 | Viewed by 4695

Abstract

In future scenarios of heterogeneous and dense networks, randomly-deployed small star networks (SSNs) become a key paradigm, whose system performance is restricted to inter-SSN interference and requires an efficient resource allocation scheme for interference coordination. Traditional resource allocation schemes do not specifically focus [...] Read more.

In future scenarios of heterogeneous and dense networks, randomly-deployed small star networks (SSNs) become a key paradigm, whose system performance is restricted to inter-SSN interference and requires an efficient resource allocation scheme for interference coordination. Traditional resource allocation schemes do not specifically focus on this paradigm and are usually too time consuming in dense networks. In this article, a very efficient graph-based scheme is proposed, which applies the maximal independent set (MIS) concept in graph theory to help divide SSNs into almost interference-free groups. We first construct an interference graph for the system based on a derived distance threshold indicating for any pair of SSNs whether there is intolerable inter-SSN interference or not. Then, SSNs are divided into MISs, and the same resource can be repetitively used by all the SSNs in each MIS. Empirical parameters and equations are set in the scheme to guarantee high performance. Finally, extensive scenarios both dense and nondense are randomly generated and simulated to demonstrate the performance of our scheme, indicating that it outperforms the classical max K-cut-based scheme in terms of system capacity, utility and especially time cost. Its achieved system capacity, utility and fairness can be close to the near-optimal strategy obtained by a time-consuming simulated annealing search. Full article

(This article belongs to the Collection Smart Communication Protocols and Algorithms for Sensor Networks)

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17 pages, 4621 KiB

Open AccessArticle

A Robust High-Accuracy Ultrasound Indoor Positioning System Based on a Wireless Sensor Network

by Jun Qi^1,*

and Guo-Ping Liu^1,2

¹ School of Astronautics, Harbin Institute of Technology, Harbin 150001, China

² School of Engineering, University of South Wales, CF37 1DL Pontypridd, Wales, UK

Sensors 2017, 17(11), 2554; https://doi.org/10.3390/s17112554 - 6 Nov 2017

Cited by 118 | Viewed by 13007

Abstract

This paper describes the development and implementation of a robust high-accuracy ultrasonic indoor positioning system (UIPS). The UIPS consists of several wireless ultrasonic beacons in the indoor environment. Each of them has a fixed and known position coordinate and can collect all the [...] Read more.

This paper describes the development and implementation of a robust high-accuracy ultrasonic indoor positioning system (UIPS). The UIPS consists of several wireless ultrasonic beacons in the indoor environment. Each of them has a fixed and known position coordinate and can collect all the transmissions from the target node or emit ultrasonic signals. Every wireless sensor network (WSN) node has two communication modules: one is WiFi, that transmits the data to the server, and the other is the radio frequency (RF) module, which is only used for time synchronization between different nodes, with accuracy up to 1 μs. The distance between the beacon and the target node is calculated by measuring the time-of-flight (TOF) for the ultrasonic signal, and then the position of the target is computed by some distances and the coordinate of the beacons. TOF estimation is the most important technique in the UIPS. A new time domain method to extract the envelope of the ultrasonic signals is presented in order to estimate the TOF. This method, with the envelope detection filter, estimates the value with the sampled values on both sides based on the least squares method (LSM). The simulation results show that the method can achieve envelope detection with a good filtering effect by means of the LSM. The highest precision and variance can reach

0.61 mm

and

0.23 mm, respectively, in pseudo-range measurements with UIPS. A maximum location error of

10.2

mm is achieved in the positioning experiments for a moving robot, when UIPS works on the line-of-sight (LOS) signal. Full article

(This article belongs to the Special Issue Sensors and Sensing in Indoor Localization, Tracking, Navigation and Activity Monitoring)

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14 pages, 4750 KiB

Open AccessArticle

A Real-Time Smooth Weighted Data Fusion Algorithm for Greenhouse Sensing Based on Wireless Sensor Networks

by Tengyue Zou^*, Yuanxia Wang, Mengyi Wang and Shouying Lin

College of Mechanical and Electronic Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, China

Sensors 2017, 17(11), 2555; https://doi.org/10.3390/s17112555 - 6 Nov 2017

Cited by 11 | Viewed by 5847

Abstract

Wireless sensor networks are widely used to acquire environmental parameters to support agricultural production. However, data variation and noise caused by actuators often produce complex measurement conditions. These factors can lead to nonconformity in reporting samples from different nodes and cause errors when [...] Read more.

Wireless sensor networks are widely used to acquire environmental parameters to support agricultural production. However, data variation and noise caused by actuators often produce complex measurement conditions. These factors can lead to nonconformity in reporting samples from different nodes and cause errors when making a final decision. Data fusion is well suited to reduce the influence of actuator-based noise and improve automation accuracy. A key step is to identify the sensor nodes disturbed by actuator noise and reduce their degree of participation in the data fusion results. A smoothing value is introduced and a searching method based on Prim’s algorithm is designed to help obtain stable sensing data. A voting mechanism with dynamic weights is then proposed to obtain the data fusion result. The dynamic weighting process can sharply reduce the influence of actuator noise in data fusion and gradually condition the data to normal levels over time. To shorten the data fusion time in large networks, an acceleration method with prediction is also presented to reduce the data collection time. A real-time system is implemented on STMicroelectronics STM32F103 and NORDIC nRF24L01 platforms and the experimental results verify the improvement provided by these new algorithms. Full article

(This article belongs to the Special Issue Sensors in Agriculture)

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17 pages, 14538 KiB

Open AccessArticle

Deep Recurrent Neural Networks for Human Activity Recognition

by Abdulmajid Murad and Jae-Young Pyun^*

Department of Information Communication Engineering, Chosun University, 375 Susuk-dong, Dong-gu, Gwangju 501-759, Korea

Sensors 2017, 17(11), 2556; https://doi.org/10.3390/s17112556 - 6 Nov 2017

Cited by 410 | Viewed by 27526

Abstract

Adopting deep learning methods for human activity recognition has been effective in extracting discriminative features from raw input sequences acquired from body-worn sensors. Although human movements are encoded in a sequence of successive samples in time, typical machine learning methods perform recognition tasks [...] Read more.

Adopting deep learning methods for human activity recognition has been effective in extracting discriminative features from raw input sequences acquired from body-worn sensors. Although human movements are encoded in a sequence of successive samples in time, typical machine learning methods perform recognition tasks without exploiting the temporal correlations between input data samples. Convolutional neural networks (CNNs) address this issue by using convolutions across a one-dimensional temporal sequence to capture dependencies among input data. However, the size of convolutional kernels restricts the captured range of dependencies between data samples. As a result, typical models are unadaptable to a wide range of activity-recognition configurations and require fixed-length input windows. In this paper, we propose the use of deep recurrent neural networks (DRNNs) for building recognition models that are capable of capturing long-range dependencies in variable-length input sequences. We present unidirectional, bidirectional, and cascaded architectures based on long short-term memory (LSTM) DRNNs and evaluate their effectiveness on miscellaneous benchmark datasets. Experimental results show that our proposed models outperform methods employing conventional machine learning, such as support vector machine (SVM) and k-nearest neighbors (KNN). Additionally, the proposed models yield better performance than other deep learning techniques, such as deep believe networks (DBNs) and CNNs. Full article

(This article belongs to the Special Issue Sensor Signal and Information Processing)

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13 pages, 12117 KiB

Open AccessArticle

Super-Resolution of Plant Disease Images for the Acceleration of Image-based Phenotyping and Vigor Diagnosis in Agriculture

by Kyosuke Yamamoto^*

, Takashi Togami and Norio Yamaguchi

PS Solutions Corp., 1-5-2 Higashi-Shimbashi, Minato-ku, Tokyo 105-7104, Japan

Sensors 2017, 17(11), 2557; https://doi.org/10.3390/s17112557 - 6 Nov 2017

Cited by 105 | Viewed by 11127

Abstract

Unmanned aerial vehicles (UAVs or drones) are a very promising branch of technology, and they have been utilized in agriculture—in cooperation with image processing technologies—for phenotyping and vigor diagnosis. One of the problems in the utilization of UAVs for agricultural purposes is the [...] Read more.

Unmanned aerial vehicles (UAVs or drones) are a very promising branch of technology, and they have been utilized in agriculture—in cooperation with image processing technologies—for phenotyping and vigor diagnosis. One of the problems in the utilization of UAVs for agricultural purposes is the limitation in flight time. It is necessary to fly at a high altitude to capture the maximum number of plants in the limited time available, but this reduces the spatial resolution of the captured images. In this study, we applied a super-resolution method to the low-resolution images of tomato diseases to recover detailed appearances, such as lesions on plant organs. We also conducted disease classification using high-resolution, low-resolution, and super-resolution images to evaluate the effectiveness of super-resolution methods in disease classification. Our results indicated that the super-resolution method outperformed conventional image scaling methods in spatial resolution enhancement of tomato disease images. The results of disease classification showed that the accuracy attained was also better by a large margin with super-resolution images than with low-resolution images. These results indicated that our approach not only recovered the information lost in low-resolution images, but also exerted a beneficial influence on further image analysis. The proposed approach will accelerate image-based phenotyping and vigor diagnosis in the field, because it not only saves time to capture images of a crop in a cultivation field but also secures the accuracy of these images for further analysis. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan 2017)

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15 pages, 3935 KiB

Open AccessArticle

Single-Shot Dense Depth Sensing with Color Sequence Coded Fringe Pattern

by Fu Li^*, Baoyu Zhang, Guangming Shi, Yi Niu, Ruodai Li, Lili Yang and Xuemei Xie

School of Electronic Engineering, Xidian University, Xi’an 710071, China

Sensors 2017, 17(11), 2558; https://doi.org/10.3390/s17112558 - 6 Nov 2017

Cited by 8 | Viewed by 4727

Abstract

A single-shot structured light method is widely used to acquire dense and accurate depth maps for dynamic scenes. In this paper, we propose a color sequence coded fringe depth sensing method. To overcome the phase unwrapping problem encountered in phase-based methods, the color-coded [...] Read more.

A single-shot structured light method is widely used to acquire dense and accurate depth maps for dynamic scenes. In this paper, we propose a color sequence coded fringe depth sensing method. To overcome the phase unwrapping problem encountered in phase-based methods, the color-coded sequence information is embedded into the phase information. We adopt the color-encoded De Bruijn sequence to denote the period of the phase information and assign the sequence into two channels of the pattern, while the third channel is used to code the phase information. Benefiting from this coding strategy, the phase information distributed in multiple channels can improve the quality of the phase intensity by channel overlay, which results in precise phase estimation. Meanwhile, the wrapped phase period assists the sequence decoding to obtain a precise period order. To evaluate the performance of the proposed method, an experimental platform is established. Quantitative and qualitative experiments demonstrate that the proposed method generates a higher precision depth, as compared to a Kinect and larger resolution ToF (Time of Flight) camera. Full article

(This article belongs to the Special Issue Imaging Depth Sensors—Sensors, Algorithms and Applications)

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8 pages, 2449 KiB

Open AccessArticle

Label-Free Detection of Cancer Biomarkers Using an In-Line Taper Fiber-Optic Interferometer and a Fiber Bragg Grating

by Dandan Sun^1,*, Yang Ran²

and Guanjun Wang³

¹ College of Physics and Electronic Engineering, Shanxi University, Taiyuan 030006, China

² Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510632, China

³ School of Information and Communication Engineering, North University of China, Taiyuan 030051, China

Sensors 2017, 17(11), 2559; https://doi.org/10.3390/s17112559 - 6 Nov 2017

Cited by 77 | Viewed by 7241

Abstract

A compact and label-free optical fiber sensor based on a taper interferometer cascaded with a fiber Bragg grating (FBG) is proposed and experimentally demonstrated for detection of a breast cancer biomarker (HER2). The tapered fiber-optic interferometer is extremely sensitive to the ambient refractive [...] Read more.

A compact and label-free optical fiber sensor based on a taper interferometer cascaded with a fiber Bragg grating (FBG) is proposed and experimentally demonstrated for detection of a breast cancer biomarker (HER2). The tapered fiber-optic interferometer is extremely sensitive to the ambient refractive index (RI). In addition, being insensitive to the RI variation, the FBG can be applied as a temperature thermometer due to its independent response to the temperature. Surface functionalization to the sensor is carried out to achieve specific targeting of the unlabeled biomarkers. The result shows that the proposed sensor presents a low limit-of-detection (LOD) of 2 ng/mL, enabling its potentials of application in early diagnosis on the breast cancer. Full article

(This article belongs to the Special Issue Label-Free Biosensors)

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10 pages, 3901 KiB

Open AccessArticle

The Development of an IMU Integrated Clothes for Postural Monitoring Using Conductive Yarn and Interconnecting Technology

by Sung-Won Kang¹, Hyeob Choi²

, Hyung-Il Park¹, Byoung-Gun Choi¹, Hyobin Im³

, Dongjun Shin⁴, Young-Giu Jung⁵, Jun-Young Lee⁵, Hong-Won Park⁶, Sukyung Park^2,* and Jung-Sim Roh^7,*

¹ Electronics and Telecommunications Research Institute, Daejeon 34129, Korea

² Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea

³ Department of Fashion & Textiles, konkuk University, Seoul 05029, Korea

⁴ BNSoft, Inc., Seoul 08378, Korea

⁵ YM-Naeultech, Incheon 22212, Korea

⁶ Korea High Tech Textile Research Institute, Yangju-si 11410, Korea

⁷ Department of Fashion & Textiles, Sangmyung University, Seoul 03016, Korea

Sensors 2017, 17(11), 2560; https://doi.org/10.3390/s17112560 - 7 Nov 2017

Cited by 36 | Viewed by 8286

Abstract

Spinal disease is a common yet important condition that occurs because of inappropriate posture. Prevention could be achieved by continuous posture monitoring, but most measurement systems cannot be used in daily life due to factors such as burdensome wires and large sensing modules. [...] Read more.

Spinal disease is a common yet important condition that occurs because of inappropriate posture. Prevention could be achieved by continuous posture monitoring, but most measurement systems cannot be used in daily life due to factors such as burdensome wires and large sensing modules. To improve upon these weaknesses, we developed comfortable “smart wear” for posture measurement using conductive yarn for circuit patterning and a flexible printed circuit board (FPCB) for interconnections. The conductive yarn was made by twisting polyester yarn and metal filaments, and the resistance per unit length was about 0.05 Ω/cm. An embroidered circuit was made using the conductive yarn, which showed increased yield strength and uniform electrical resistance per unit length. Circuit networks of sensors and FPCBs for interconnection were integrated into clothes using a computer numerical control (CNC) embroidery process. The system was calibrated and verified by comparing the values measured by the smart wear with those measured by a motion capture camera system. Six subjects performed fixed movements and free computer work, and, with this system, we were able to measure the anterior/posterior direction tilt angle with an error of less than 4°. The smart wear does not have excessive wires, and its structure will be optimized for better posture estimation in a later study. Full article

(This article belongs to the Special Issue Wearable and Ambient Sensors for Healthcare and Wellness Applications)

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10 pages, 2798 KiB

Open AccessArticle

A Generalized Polynomial Chaos-Based Approach to Analyze the Impacts of Process Deviations on MEMS Beams

by Lili Gao, Zai-Fa Zhou^*

and Qing-An Huang^*

Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 210096, China

Sensors 2017, 17(11), 2561; https://doi.org/10.3390/s17112561 - 8 Nov 2017

Cited by 9 | Viewed by 4352

Abstract

A microstructure beam is one of the fundamental elements in MEMS devices like cantilever sensors, RF/optical switches, varactors, resonators, etc. It is still difficult to precisely predict the performance of MEMS beams with the current available simulators due to the inevitable process deviations. [...] Read more.

A microstructure beam is one of the fundamental elements in MEMS devices like cantilever sensors, RF/optical switches, varactors, resonators, etc. It is still difficult to precisely predict the performance of MEMS beams with the current available simulators due to the inevitable process deviations. Feasible numerical methods are required and can be used to improve the yield and profits of the MEMS devices. In this work, process deviations are considered to be stochastic variables, and a newly-developed numerical method, i.e., generalized polynomial chaos (GPC), is applied for the simulation of the MEMS beam. The doubly-clamped polybeam has been utilized to verify the accuracy of GPC, compared with our Monte Carlo (MC) approaches. Performance predictions have been made on the residual stress by achieving its distributions in GaAs Monolithic Microwave Integrated Circuit (MMIC)-based MEMS beams. The results show that errors are within 1% for the results of GPC approximations compared with the MC simulations. Appropriate choices of the 4-order GPC expansions with orthogonal terms have also succeeded in reducing the MC simulation labor. The mean value of the residual stress, concluded from experimental tests, shares an error about 1.1% with that of the 4-order GPC method. It takes a probability around 54.3% for the 4-order GPC approximation to attain the mean test value of the residual stress. The corresponding yield occupies over 90 percent around the mean within the twofold standard deviations. Full article

(This article belongs to the Collection Modeling, Testing and Reliability Issues in MEMS Engineering)

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27 pages, 3248 KiB

Open AccessArticle

The Virtual Environment for Rapid Prototyping of the Intelligent Environment

by Yannick Francillette^*

, Eric Boucher

, Abdenour Bouzouane and Sébastien Gaboury

Université du Québec à Chicoutimi, LIARA, Chicoutimi, QC G7H 2B1, Canada

Sensors 2017, 17(11), 2562; https://doi.org/10.3390/s17112562 - 7 Nov 2017

Cited by 22 | Viewed by 6079

Abstract

Advances in domains such as sensor networks and electronic and ambient intelligence have allowed us to create intelligent environments (IEs). However, research in IE is being held back by the fact that researchers face major difficulties, such as a lack of resources for [...] Read more.

Advances in domains such as sensor networks and electronic and ambient intelligence have allowed us to create intelligent environments (IEs). However, research in IE is being held back by the fact that researchers face major difficulties, such as a lack of resources for their experiments. Indeed, they cannot easily build IEs to evaluate their approaches. This is mainly because of economic and logistical issues. In this paper, we propose a simulator to build virtual IEs. Simulators are a good alternative to physical IEs because they are inexpensive, and experiments can be conducted easily. Our simulator is open source and it provides users with a set of virtual sensors that simulates the behavior of real sensors. This simulator gives the user the capacity to build their own environment, providing a model to edit inhabitants’ behavior and an interactive mode. In this mode, the user can directly act upon IE objects. This simulator gathers data generated by the interactions in order to produce datasets. These datasets can be used by scientists to evaluate several approaches in IEs. Full article

(This article belongs to the Special Issue Advances in Sensors for Sustainable Smart Cities and Smart Buildings)

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12 pages, 3536 KiB

Open AccessArticle

Surface-Enhanced Resonance Raman Scattering of Rhodamine 6G in Dispersions and on Films of Confeito-Like Au Nanoparticles

by Masaki Ujihara^1,*, Nhut Minh Dang² and Toyoko Imae^1,2

¹ Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, 43 Keelung Road, Section 4, Taipei 10607, Taiwan

² Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Keelung Road, Section 4, Taipei 10607, Taiwan

Sensors 2017, 17(11), 2563; https://doi.org/10.3390/s17112563 - 7 Nov 2017

Cited by 22 | Viewed by 7031

Abstract

Surface-enhanced resonance Raman scattering (SERRS) of rhodamine 6G was measured on confeito-like Au nanoparticles (CAuNPs). The large CAuNPs (100 nm in diameter) in aqueous dispersion systems showed stronger enhancing effect (analytical enhancement factor: over 10⁵) of SERRS than the small CAuNPs [...] Read more.

Surface-enhanced resonance Raman scattering (SERRS) of rhodamine 6G was measured on confeito-like Au nanoparticles (CAuNPs). The large CAuNPs (100 nm in diameter) in aqueous dispersion systems showed stronger enhancing effect (analytical enhancement factor: over 10⁵) of SERRS than the small CAuNPs (50 nm in diameter), while the spherical Au nanoparticles (20 nm in diameter) displayed rather weak intensities. Especially, minor bands in 1400–1600 cm⁻¹ were uniquely enhanced by the resonance effect of CAuNPs. The enhancement factors revealed a concentration dependence of the enhancing effect at low concentration of rhodamine 6G. This dependency was due to a large capacity of hot-spots on CAuNPs, which were formed without agglomeration. The surface-enhancing behaviour in the film systems was similar to that in the dispersions, although the large CAuNPs had lower enhancing effect in the films, and the small CAuNPs and the spherical Au nanoparticles were more effective in their films. These results suggest that the CAuNPs have an advantage in ultrasensitive devices both in dispersions and films, compared to the agglomerate of spherical Au nanoparticles. Full article

(This article belongs to the Special Issue Surface Plasmon Resonance Sensing)

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22 pages, 17539 KiB

Open AccessArticle

Recognition and Matching of Clustered Mature Litchi Fruits Using Binocular Charge-Coupled Device (CCD) Color Cameras

by Chenglin Wang¹, Yunchao Tang^2,*, Xiangjun Zou^1,*, Lufeng Luo³ and Xiong Chen¹

¹ Key Laboratory of Key Technology on Agricultural Machine and Equipment, Ministry of Education, South China Agricultural University, Guangzhou 510642, China

² School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, China

³ School of Mechanical and Electrical Engineering, Foshan University, Foshan 528000, China

Sensors 2017, 17(11), 2564; https://doi.org/10.3390/s17112564 - 7 Nov 2017

Cited by 60 | Viewed by 7158

Abstract

Recognition and matching of litchi fruits are critical steps for litchi harvesting robots to successfully grasp litchi. However, due to the randomness of litchi growth, such as clustered growth with uncertain number of fruits and random occlusion by leaves, branches and other fruits, [...] Read more.

Recognition and matching of litchi fruits are critical steps for litchi harvesting robots to successfully grasp litchi. However, due to the randomness of litchi growth, such as clustered growth with uncertain number of fruits and random occlusion by leaves, branches and other fruits, the recognition and matching of the fruit become a challenge. Therefore, this study firstly defined mature litchi fruit as three clustered categories. Then an approach for recognition and matching of clustered mature litchi fruit was developed based on litchi color images acquired by binocular charge-coupled device (CCD) color cameras. The approach mainly included three steps: (1) calibration of binocular color cameras and litchi image acquisition; (2) segmentation of litchi fruits using four kinds of supervised classifiers, and recognition of the pre-defined categories of clustered litchi fruit using a pixel threshold method; and (3) matching the recognized clustered fruit using a geometric center-based matching method. The experimental results showed that the proposed recognition method could be robust against the influences of varying illumination and occlusion conditions, and precisely recognize clustered litchi fruit. In the tested 432 clustered litchi fruits, the highest and lowest average recognition rates were 94.17% and 92.00% under sunny back-lighting and partial occlusion, and sunny front-lighting and non-occlusion conditions, respectively. From 50 pairs of tested images, the highest and lowest matching success rates were 97.37% and 91.96% under sunny back-lighting and non-occlusion, and sunny front-lighting and partial occlusion conditions, respectively. Full article

(This article belongs to the Special Issue Charge-Coupled Device (CCD) Sensors)

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19 pages, 1720 KiB

Open AccessArticle

Optimal Quantization Scheme for Data-Efficient Target Tracking via UWSNs Using Quantized Measurements

by Senlin Zhang^1,2, Huayan Chen², Meiqin Liu^1,2,*

and Qunfei Zhang³

¹ State Key Laboratory of Industrial Control Technology, Hangzhou 310027, China

² College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China

³ School of Marine Science and Technology, Northwestern Polytechnical University, Xi’an 710072, China

Sensors 2017, 17(11), 2565; https://doi.org/10.3390/s17112565 - 7 Nov 2017

Cited by 17 | Viewed by 4330

Abstract

Target tracking is one of the broad applications of underwater wireless sensor networks (UWSNs). However, as a result of the temporal and spatial variability of acoustic channels, underwater acoustic communications suffer from an extremely limited bandwidth. In order to reduce network congestion, it [...] Read more.

Target tracking is one of the broad applications of underwater wireless sensor networks (UWSNs). However, as a result of the temporal and spatial variability of acoustic channels, underwater acoustic communications suffer from an extremely limited bandwidth. In order to reduce network congestion, it is important to shorten the length of the data transmitted from local sensors to the fusion center by quantization. Although quantization can reduce bandwidth cost, it also brings about bad tracking performance as a result of information loss after quantization. To solve this problem, this paper proposes an optimal quantization-based target tracking scheme. It improves the tracking performance of low-bit quantized measurements by minimizing the additional covariance caused by quantization. The simulation demonstrates that our scheme performs much better than the conventional uniform quantization-based target tracking scheme and the increment of the data length affects our scheme only a little. Its tracking performance improves by only 4.4% from 2- to 3-bit, which means our scheme weakly depends on the number of data bits. Moreover, our scheme also weakly depends on the number of participate sensors, and it can work well in sparse sensor networks. In a

6 \times 6 \times 6

sensor network, compared with

4 \times 4 \times 4

sensor networks, the number of participant sensors increases by 334.92%, while the tracking accuracy using 1-bit quantized measurements improves by only 50.77%. Overall, our optimal quantization-based target tracking scheme can achieve the pursuit of data-efficiency, which fits the requirements of low-bandwidth UWSNs. Full article

(This article belongs to the Special Issue Advances and Challenges in Underwater Sensor Networks)

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21 pages, 6514 KiB

Open AccessArticle

An Embedded Wireless Sensor Network with Wireless Power Transmission Capability for the Structural Health Monitoring of Reinforced Concrete Structures

by Luca Gallucci¹, Costantino Menna^2,*, Leopoldo Angrisani³

, Domenico Asprone², Rosario Schiano Lo Moriello⁴

, Francesco Bonavolontà³

and Francesco Fabbrocino⁵

¹ TME s.r.l.—Test and Manufacturing Engineering, via C. A. Dalla Chiesa—81050, Portico di Caserta (CE), Italy

² Dipartimento di Strutture per l’Ingegneria e l’Architettura, University of Naples Federico II, Via Claudio 21, 80125 Naples, Italy

³ Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, University of Naples Federico II, Via Claudio 21, 80125 Naples, Italy

⁴ Dipartimento di Ingegneria Industriale, University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy

⁵ Dipartimento di Ingegneria, Università Telematica Pegaso-Piazza Trieste e Trento 48, 80132 Naples, Italy

Sensors 2017, 17(11), 2566; https://doi.org/10.3390/s17112566 - 7 Nov 2017

Cited by 55 | Viewed by 7469

Abstract

Maintenance strategies based on structural health monitoring can provide effective support in the optimization of scheduled repair of existing structures, thus enabling their lifetime to be extended. With specific regard to reinforced concrete (RC) structures, the state of the art seems to still [...] Read more.

Maintenance strategies based on structural health monitoring can provide effective support in the optimization of scheduled repair of existing structures, thus enabling their lifetime to be extended. With specific regard to reinforced concrete (RC) structures, the state of the art seems to still be lacking an efficient and cost-effective technique capable of monitoring material properties continuously over the lifetime of a structure. Current solutions can typically only measure the required mechanical variables in an indirect, but economic, manner, or directly, but expensively. Moreover, most of the proposed solutions can only be implemented by means of manual activation, making the monitoring very inefficient and then poorly supported. This paper proposes a structural health monitoring system based on a wireless sensor network (WSN) that enables the automatic monitoring of a complete structure. The network includes wireless distributed sensors embedded in the structure itself, and follows the monitoring-based maintenance (MBM) approach, with its ABCDE paradigm, namely: accuracy, benefit, compactness, durability, and easiness of operations. The system is structured in a node level and has a network architecture that enables all the node data to converge in a central unit. Human control is completely unnecessary until the periodic evaluation of the collected data. Several tests are conducted in order to characterize the system from a metrological point of view and assess its performance and effectiveness in real RC conditions. Full article

(This article belongs to the Special Issue Advances in Sensors for Sustainable Smart Cities and Smart Buildings)

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25 pages, 4508 KiB

Open AccessArticle

Adaptive Monocular Visual–Inertial SLAM for Real-Time Augmented Reality Applications in Mobile Devices

by Jin-Chun Piao

and Shin-Dug Kim^*

Department of Computer Science, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea

Sensors 2017, 17(11), 2567; https://doi.org/10.3390/s17112567 - 7 Nov 2017

Cited by 34 | Viewed by 10008

Abstract

Simultaneous localization and mapping (SLAM) is emerging as a prominent issue in computer vision and next-generation core technology for robots, autonomous navigation and augmented reality. In augmented reality applications, fast camera pose estimation and true scale are important. In this paper, we present [...] Read more.

Simultaneous localization and mapping (SLAM) is emerging as a prominent issue in computer vision and next-generation core technology for robots, autonomous navigation and augmented reality. In augmented reality applications, fast camera pose estimation and true scale are important. In this paper, we present an adaptive monocular visual–inertial SLAM method for real-time augmented reality applications in mobile devices. First, the SLAM system is implemented based on the visual–inertial odometry method that combines data from a mobile device camera and inertial measurement unit sensor. Second, we present an optical-flow-based fast visual odometry method for real-time camera pose estimation. Finally, an adaptive monocular visual–inertial SLAM is implemented by presenting an adaptive execution module that dynamically selects visual–inertial odometry or optical-flow-based fast visual odometry. Experimental results show that the average translation root-mean-square error of keyframe trajectory is approximately 0.0617 m with the EuRoC dataset. The average tracking time is reduced by 7.8%, 12.9%, and 18.8% when different level-set adaptive policies are applied. Moreover, we conducted experiments with real mobile device sensors, and the results demonstrate the effectiveness of performance improvement using the proposed method. Full article

(This article belongs to the Special Issue Indoor LiDAR/Vision Systems)

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15 pages, 2754 KiB

Open AccessArticle

Generalized Nonlinear Chirp Scaling Algorithm for High-Resolution Highly Squint SAR Imaging

by Tianzhu Yi^1,*

, Zhihua He¹, Feng He¹, Zhen Dong¹ and Manqing Wu²

¹ School of Electronic Science and Engineering, National University of Defense Technology, Sanyi Avenue, Changsha 410073, China

² China Electronics Technology Group Corporation (CETC), China Academy of Electronics and Information Technology, Beijing 100846, China

Sensors 2017, 17(11), 2568; https://doi.org/10.3390/s17112568 - 7 Nov 2017

Cited by 9 | Viewed by 4525

Abstract

This paper presents a modified approach for high-resolution, highly squint synthetic aperture radar (SAR) data processing. Several nonlinear chirp scaling (NLCS) algorithms have been proposed to solve the azimuth variance of the frequency modulation rates that are caused by the linear range walk [...] Read more.

This paper presents a modified approach for high-resolution, highly squint synthetic aperture radar (SAR) data processing. Several nonlinear chirp scaling (NLCS) algorithms have been proposed to solve the azimuth variance of the frequency modulation rates that are caused by the linear range walk correction (LRWC). However, the azimuth depth of focusing (ADOF) is not handled well by these algorithms. The generalized nonlinear chirp scaling (GNLCS) algorithm that is proposed in this paper uses the method of series reverse (MSR) to improve the ADOF and focusing precision. It also introduces a high order processing kernel to avoid the range block processing. Simulation results show that the GNLCS algorithm can enlarge the ADOF and focusing precision for high-resolution highly squint SAR data. Full article

(This article belongs to the Section Remote Sensors)

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10 pages, 2289 KiB

Open AccessArticle

Carbon Nanotubes as Fluorescent Labels for Surface Plasmon Resonance-Assisted Fluoroimmunoassay

by Hiroki Ashiba^1,*, Yoko Iizumi², Toshiya Okazaki², Xiaomin Wang^3,†

and Makoto Fujimaki¹

¹ Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan

² CNT-Application Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan

³ Nanoelectronics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan

^† Present address: Research and Development Division, Optoquest Co., Ltd., Ageo, Saitama 362-0021, Japan

Sensors 2017, 17(11), 2569; https://doi.org/10.3390/s17112569 - 7 Nov 2017

Cited by 8 | Viewed by 4653

Abstract

The photoluminescence properties of carbon nanotubes (CNTs), including the large Stokes shift and the absence of fluorescent photobleaching, can be used as a fluorescent label in biological measurements. In this study, the performance of CNTs as a fluorescent label for surface plasmon resonance [...] Read more.

The photoluminescence properties of carbon nanotubes (CNTs), including the large Stokes shift and the absence of fluorescent photobleaching, can be used as a fluorescent label in biological measurements. In this study, the performance of CNTs as a fluorescent label for surface plasmon resonance (SPR)-assisted fluoroimmunoassay is evaluated. The fluorescence of (8, 3) CNTs with an excitation wavelength of 670 nm and an emission wavelength of 970 nm is observed using a sensor chip equipped with a prism-integrated microfluidic channel to excite the SPR. The minimum detectable concentration of a CNT dispersed in water using a visible camera is 0.25 μg/mL, which is equivalent to 2 × 10¹⁰ tubes/mL. The target analyte detection using the CNT fluorescent labels is theoretically investigated by evaluating the detectable number of CNTs in a detection volume. Assuming detection of virus particles which are bound with 100 CNT labels, the minimum number of detectable virus particles is calculated to be 900. The result indicates that CNTs are effective fluorescent labels for SPR-assisted fluoroimmunoassay. Full article

(This article belongs to the Special Issue Fluorescent Probes and Sensors)

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17 pages, 2525 KiB

Open AccessArticle

Development of Ratiometric Fluorescent Biosensors for the Determination of Creatine and Creatinine in Urine

by Hong Dinh Duong and Jong Il Rhee^*

School of Chemical Engineering, Research Center for Biophotonics, Chonnam National University, Yong-Bong Ro77, 61186 Gwangju, Korea

Sensors 2017, 17(11), 2570; https://doi.org/10.3390/s17112570 - 8 Nov 2017

Cited by 20 | Viewed by 6994

Abstract

In this study, the oxazine 170 perchlorate (O17)-ethylcellulose (EC) membrane was successfully exploited for the fabrication of creatine- and creatinine-sensing membranes. The sensing membrane exhibited a double layer of O17-EC membrane and a layer of enzyme(s) entrapped in the EC and polyurethane hydrogel [...] Read more.

In this study, the oxazine 170 perchlorate (O17)-ethylcellulose (EC) membrane was successfully exploited for the fabrication of creatine- and creatinine-sensing membranes. The sensing membrane exhibited a double layer of O17-EC membrane and a layer of enzyme(s) entrapped in the EC and polyurethane hydrogel (PU) matrix. The sensing principle of the membranes was based on the hydrolytic catalysis of urea, creatine, and creatinine by the enzymes. The reaction end product, ammonia, reacted with O17-EC membrane, resulting in the change in fluorescence intensities at two emission wavelengths (λ_em = 565 and 625 nm). Data collected from the ratio of fluorescence intensities at λ_em = 565 and 625 nm were proportional to the concentrations of creatine or creatinine. Creatine- and creatinine-sensing membranes were very sensitive to creatine and creatinine at the concentration range of 0.1–1.0 mM, with a limit of detection (LOD) of 0.015 and 0.0325 mM, respectively. Furthermore, these sensing membranes showed good features in terms of response time, reversibility, and long-term stability. The interference study demonstrated that some components such as amino acids and salts had some negative effects on the analytical performance of the membranes. Thus, the simple and sensitive ratiometric fluorescent sensors provide a simple and comprehensive method for the determination of creatine and creatinine concentrations in urine. Full article

(This article belongs to the Special Issue Fluorescent Probes and Sensors)

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12 pages, 26277 KiB

Open AccessArticle

Field Tests of a Portable MEMS Gravimeter

by Richard P. Middlemiss^1,*

, Steven G. Bramsiepe¹, Rebecca Douglas¹, James Hough¹, Douglas J. Paul²

, Sheila Rowan¹ and Giles D. Hammond¹

¹ School of Physics and Astronomy, University of Glasgow, Kelvin Building, University Avenue, Glasgow G12 8SU, UK

² School of Engineering, University of Glasgow, Rankine Building, Oakfield Avenue, Glasgow G12 8LT, UK

Sensors 2017, 17(11), 2571; https://doi.org/10.3390/s17112571 - 8 Nov 2017

Cited by 33 | Viewed by 10464

Abstract

Gravimeters are used to measure density anomalies under the ground. They are applied in many different fields from volcanology to oil and gas exploration, but present commercial systems are costly and massive. A new type of gravity sensor has been developed that utilises [...] Read more.

Gravimeters are used to measure density anomalies under the ground. They are applied in many different fields from volcanology to oil and gas exploration, but present commercial systems are costly and massive. A new type of gravity sensor has been developed that utilises the same fabrication methods as those used to make mobile phone accelerometers. In this study, we describe the first results of a field-portable microelectromechanical system (MEMS) gravimeter. The stability of the gravimeter is demonstrated through undertaking a multi-day measurement with a standard deviation of

5.58 \times 10^{- 6}

ms

^{- 2}

. It is then demonstrated that a change in gravitational acceleration of

4.5 \times 10^{- 5}

ms

^{- 2}

can be measured as the device is moved between the top and the bottom of a 20.7 m lift shaft with a signal-to-noise ratio (SNR) of 14.25. Finally, the device is demonstrated to be stable in a more harsh environment: a

4.5 \times 10^{- 4}

ms

^{- 2}

gravity variation is measured between the top and bottom of a 275-m hill with an SNR of 15.88. These initial field-tests are an important step towards a chip-sized gravity sensor. Full article

(This article belongs to the Collection Modeling, Testing and Reliability Issues in MEMS Engineering)

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24 pages, 11452 KiB

Open AccessArticle

A Smartphone Step Counter Using IMU and Magnetometer for Navigation and Health Monitoring Applications

by Maan Khedr^1,2,* and Nasser El-Sheimy¹

¹ Department of Geomatics Engineering, University of Calgary, 2500 University Dr NW, Calgary, AB T2N1N4, Canada

² Department of Computer Engineering, Arab Academy for Science and Technology, Alexandria, P.O. Box 1029, Egypt

Sensors 2017, 17(11), 2573; https://doi.org/10.3390/s17112573 - 8 Nov 2017

Cited by 33 | Viewed by 12111

Abstract

The growing market of smart devices make them appealing for various applications. Motion tracking can be achieved using such devices, and is important for various applications such as navigation, search and rescue, health monitoring, and quality of life-style assessment. Step detection is a [...] Read more.

The growing market of smart devices make them appealing for various applications. Motion tracking can be achieved using such devices, and is important for various applications such as navigation, search and rescue, health monitoring, and quality of life-style assessment. Step detection is a crucial task that affects the accuracy and quality of such applications. In this paper, a new step detection technique is proposed, which can be used for step counting and activity monitoring for health applications as well as part of a Pedestrian Dead Reckoning (PDR) system. Inertial and Magnetic sensors measurements are analyzed and fused for detecting steps under varying step modes and device pose combinations using a free-moving handheld device (smartphone). Unlike most of the state of the art research in the field, the proposed technique does not require a classifier, and adaptively tunes the filters and thresholds used without the need for presets while accomplishing the task in a real-time operation manner. Testing shows that the proposed technique successfully detects steps under varying motion speeds and device use cases with an average performance of 99.6%, and outperforms some of the state of the art techniques that rely on classifiers and commercial wristband products. Full article

(This article belongs to the Special Issue Inertial Sensors for Positioning and Navigation)

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19 pages, 2661 KiB

Open AccessArticle

Radar Constant-Modulus Waveform Optimization for High-Resolution Range Profiling of Stationary Targets

by Wenzhen Yue^*, Lin Li, Yu Xin and Tao Han

Beijing Institute of Remote Sensing Information, Beijing 100192, China

Sensors 2017, 17(11), 2574; https://doi.org/10.3390/s17112574 - 8 Nov 2017

Cited by 5 | Viewed by 3238

Abstract

The high-resolution range (HRR) profile is an important target signature in many applications (e.g., automatic target recognition), and the radar HRR profiling performance is highly dependent on radar transmitted waveforms. In this paper, we consider the constant-modulus (CM) waveform optimization problem to improve [...] Read more.

The high-resolution range (HRR) profile is an important target signature in many applications (e.g., automatic target recognition), and the radar HRR profiling performance is highly dependent on radar transmitted waveforms. In this paper, we consider the constant-modulus (CM) waveform optimization problem to improve HRR profiling performance for stationary targets. Firstly, several fundamental bounds regarding the profiling ambiguity, stability, and accuracy are derived. Further investigation reveals that the stability and accuracy of HRR profiling are unified in the white noise case. Aimed at improving the profiling stability and accuracy, we design two types of CM radar waveforms—the arbitrary-phase and QPSK waveforms—through a customized Gaussian randomization method. The performance of LFM waveforms is also discussed. Numerical experiments show that the optimized CM waveforms can dramatically enhance the profiling performance over the unoptimized ones. Full article

(This article belongs to the Section Remote Sensors)

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22 pages, 1967 KiB

Open AccessArticle

Spatial-Temporal Data Collection with Compressive Sensing in Mobile Sensor Networks

by Haifeng Zheng¹

, Jiayin Li¹, Xinxin Feng¹

, Wenzhong Guo^2,3,*, Zhonghui Chen¹ and Neal Xiong^4,*

¹ College of Physics and Information Engineering, Fuzhou University, Fuzhou 350116, China

² Fujian Provincial Key Laboratory of Network Computing and Intelligent Information Processing, Fuzhou University, Fuzhou 350116, China

³ Key Laboratory of Spatial Data Mining & Information Sharing, Ministry of Education, Fuzhou 350116, China

⁴ Department of Mathematics and Computer Science, Northeastern State University, Muskogee, OK 74401, USA

Sensors 2017, 17(11), 2575; https://doi.org/10.3390/s17112575 - 8 Nov 2017

Cited by 22 | Viewed by 5799

Abstract

Compressive sensing (CS) provides an energy-efficient paradigm for data gathering in wireless sensor networks (WSNs). However, the existing work on spatial-temporal data gathering using compressive sensing only considers either multi-hop relaying based or multiple random walks based approaches. In this paper, we exploit [...] Read more.

Compressive sensing (CS) provides an energy-efficient paradigm for data gathering in wireless sensor networks (WSNs). However, the existing work on spatial-temporal data gathering using compressive sensing only considers either multi-hop relaying based or multiple random walks based approaches. In this paper, we exploit the mobility pattern for spatial-temporal data collection and propose a novel mobile data gathering scheme by employing the Metropolis-Hastings algorithm with delayed acceptance, an improved random walk algorithm for a mobile collector to collect data from a sensing field. The proposed scheme exploits Kronecker compressive sensing (KCS) for spatial-temporal correlation of sensory data by allowing the mobile collector to gather temporal compressive measurements from a small subset of randomly selected nodes along a random routing path. More importantly, from the theoretical perspective we prove that the equivalent sensing matrix constructed from the proposed scheme for spatial-temporal compressible signal can satisfy the property of KCS models. The simulation results demonstrate that the proposed scheme can not only significantly reduce communication cost but also improve recovery accuracy for mobile data gathering compared to the other existing schemes. In particular, we also show that the proposed scheme is robust in unreliable wireless environment under various packet losses. All this indicates that the proposed scheme can be an efficient alternative for data gathering application in WSNs . Full article

(This article belongs to the Special Issue Sensor Intelligent Data Analysis for Social Networks: Theory and Applications)

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15 pages, 2101 KiB

Open AccessArticle

Feature Selection for Motor Imagery EEG Classification Based on Firefly Algorithm and Learning Automata

by Aiming Liu¹, Kun Chen^1,2,*

, Quan Liu^1,2, Qingsong Ai^1,2

, Yi Xie¹ and Anqi Chen¹

¹ School of Information Engineering, Wuhan University of Technology, Wuhan 430070, China

² Key Laboratory of Fiber Optic Sensing Technology and Information Processing, Wuhan University of Technology, Ministry of Education, Wuhan 430070, China

Sensors 2017, 17(11), 2576; https://doi.org/10.3390/s17112576 - 8 Nov 2017

Cited by 71 | Viewed by 6783

Abstract

Motor Imagery (MI) electroencephalography (EEG) is widely studied for its non-invasiveness, easy availability, portability, and high temporal resolution. As for MI EEG signal processing, the high dimensions of features represent a research challenge. It is necessary to eliminate redundant features, which not only [...] Read more.

Motor Imagery (MI) electroencephalography (EEG) is widely studied for its non-invasiveness, easy availability, portability, and high temporal resolution. As for MI EEG signal processing, the high dimensions of features represent a research challenge. It is necessary to eliminate redundant features, which not only create an additional overhead of managing the space complexity, but also might include outliers, thereby reducing classification accuracy. The firefly algorithm (FA) can adaptively select the best subset of features, and improve classification accuracy. However, the FA is easily entrapped in a local optimum. To solve this problem, this paper proposes a method of combining the firefly algorithm and learning automata (LA) to optimize feature selection for motor imagery EEG. We employed a method of combining common spatial pattern (CSP) and local characteristic-scale decomposition (LCD) algorithms to obtain a high dimensional feature set, and classified it by using the spectral regression discriminant analysis (SRDA) classifier. Both the fourth brain–computer interface competition data and real-time data acquired in our designed experiments were used to verify the validation of the proposed method. Compared with genetic and adaptive weight particle swarm optimization algorithms, the experimental results show that our proposed method effectively eliminates redundant features, and improves the classification accuracy of MI EEG signals. In addition, a real-time brain–computer interface system was implemented to verify the feasibility of our proposed methods being applied in practical brain–computer interface systems. Full article

(This article belongs to the Special Issue Biomedical Sensors and Systems 2017)

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12 pages, 6034 KiB

Open AccessArticle

Modeling and Positioning of a PZT Precision Drive System

by Che Liu and Yanling Guo^*

College of Mechanical and Electrical Engineering, Northeast Forestry University, Harbin 150040, China

Sensors 2017, 17(11), 2577; https://doi.org/10.3390/s17112577 - 8 Nov 2017

Cited by 18 | Viewed by 4058

Abstract

The fact that piezoelectric ceramic transducer (PZT) precision drive systems in 3D printing are faced with nonlinear problems with respect to positioning, such as hysteresis and creep, has had an extremely negative impact on the precision of laser focusing systems. To eliminate the [...] Read more.

The fact that piezoelectric ceramic transducer (PZT) precision drive systems in 3D printing are faced with nonlinear problems with respect to positioning, such as hysteresis and creep, has had an extremely negative impact on the precision of laser focusing systems. To eliminate the impact of PZT nonlinearity during precision drive movement, mathematical modeling and theoretical analyses of each module comprising the system were carried out in this study, a micro-displacement measurement circuit based on Position Sensitive Detector (PSD) is constructed, followed by the establishment of system closed-loop control and creep control models. An XL-80 laser interferometer (Renishaw, Wotton-under-Edge, UK) was used to measure the performance of the precision drive system, showing that system modeling and control algorithms were correct, with the requirements for precision positioning of the drive system satisfied. Full article

(This article belongs to the Section Physical Sensors)

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18 pages, 329 KiB

Open AccessArticle

A Tree Based Broadcast Scheme for (m, k)-firm Real-Time Stream in Wireless Sensor Networks

by HoSung Park¹, Beom-Su Kim¹, Kyong Hoon Kim¹, Babar Shah² and Ki-Il Kim^3,*

¹ Department of Informatics, Gyeongsang National University, Jinju 52828, Korea

² College of Technological Innovation, Zayed University, Dubai 19282, UAE

³ Department of Computer Science and Engineering, Chungnam National University, Daejeon 34134, Korea

Sensors 2017, 17(11), 2578; https://doi.org/10.3390/s17112578 - 9 Nov 2017

Cited by 4 | Viewed by 3465

Abstract

Recently, various unicast routing protocols have been proposed to deliver measured data from the sensor node to the sink node within the predetermined deadline in wireless sensor networks. In parallel with their approaches, some applications demand the specific service, which is based on [...] Read more.

Recently, various unicast routing protocols have been proposed to deliver measured data from the sensor node to the sink node within the predetermined deadline in wireless sensor networks. In parallel with their approaches, some applications demand the specific service, which is based on broadcast to all nodes within the deadline, the feasible real-time traffic model and improvements in energy efficiency. However, current protocols based on either flooding or one-to-one unicast cannot meet the above requirements entirely. Moreover, as far as the authors know, there is no study for the real-time broadcast protocol to support the application-specific traffic model in WSN yet. Based on the above analysis, in this paper, we propose a new (m, k)-firm-based Real-time Broadcast Protocol (FRBP) by constructing a broadcast tree to satisfy the (m, k)-firm, which is applicable to the real-time model in resource-constrained WSNs. The broadcast tree in FRBP is constructed by the distance-based priority scheme, whereas energy efficiency is improved by selecting as few as nodes on a tree possible. To overcome the unstable network environment, the recovery scheme invokes rapid partial tree reconstruction in order to designate another node as the parent on a tree according to the measured (m, k)-firm real-time condition and local states monitoring. Finally, simulation results are given to demonstrate the superiority of FRBP compared to the existing schemes in terms of average deadline missing ratio, average throughput and energy consumption. Full article

(This article belongs to the Section Sensor Networks)

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11 pages, 6463 KiB

Open AccessArticle

FieldSAFE: Dataset for Obstacle Detection in Agriculture

by Mikkel Fly Kragh^1,*,†

, Peter Christiansen^1,†, Morten Stigaard Laursen¹

, Morten Larsen², Kim Arild Steen³, Ole Green³, Henrik Karstoft¹ and Rasmus Nyholm Jørgensen¹

¹ Department of Engineering, Aarhus University, Aarhus N 8200, Denmark

² Conpleks Innovation ApS, Struer 7600, Denmark

³ AgroIntelli, Aarhus N 8200, Denmark

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2579; https://doi.org/10.3390/s17112579 - 9 Nov 2017

Cited by 69 | Viewed by 12859

Abstract

In this paper, we present a multi-modal dataset for obstacle detection in agriculture. The dataset comprises approximately 2 h of raw sensor data from a tractor-mounted sensor system in a grass mowing scenario in Denmark, October 2016. Sensing modalities include stereo camera, thermal [...] Read more.

In this paper, we present a multi-modal dataset for obstacle detection in agriculture. The dataset comprises approximately 2 h of raw sensor data from a tractor-mounted sensor system in a grass mowing scenario in Denmark, October 2016. Sensing modalities include stereo camera, thermal camera, web camera, 360

^{\circ}

camera, LiDAR and radar, while precise localization is available from fused IMU and GNSS. Both static and moving obstacles are present, including humans, mannequin dolls, rocks, barrels, buildings, vehicles and vegetation. All obstacles have ground truth object labels and geographic coordinates. Full article

(This article belongs to the Special Issue Sensors in Agriculture)

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33 pages, 18995 KiB

Open AccessArticle

A Decentralized Compositional Framework for Dependable Decision Process in Self-Managed Cyber Physical Systems

by Peng Zhou^1,2, Decheng Zuo¹, Kun-Mean Hou² and Zhan Zhang^1,*

¹ School of Computer Science and Technology, Harbin Institute of Technology, Harbin 150001, China

² LIMOS, UMR 6158 CNRS, Université Clermont Auvergne, BP 10125, 63173 Aubière CEDEX, France

Sensors 2017, 17(11), 2580; https://doi.org/10.3390/s17112580 - 9 Nov 2017

Cited by 13 | Viewed by 5466

Abstract

Cyber Physical Systems (CPSs) need to interact with the changeable environment under various interferences. To provide continuous and high quality services, a self-managed CPS should automatically reconstruct itself to adapt to these changes and recover from failures. Such dynamic adaptation behavior introduces systemic [...] Read more.

Cyber Physical Systems (CPSs) need to interact with the changeable environment under various interferences. To provide continuous and high quality services, a self-managed CPS should automatically reconstruct itself to adapt to these changes and recover from failures. Such dynamic adaptation behavior introduces systemic challenges for CPS design, advice evaluation and decision process arrangement. In this paper, a formal compositional framework is proposed to systematically improve the dependability of the decision process. To guarantee the consistent observation of event orders for causal reasoning, this work first proposes a relative time-based method to improve the composability and compositionality of the timing property of events. Based on the relative time solution, a formal reference framework is introduced for self-managed CPSs, which includes a compositional FSM-based actor model (subsystems of CPS), actor-based advice and runtime decomposable decisions. To simplify self-management, a self-similar recursive actor interface is proposed for decision (actor) composition. We provide constraints and seven patterns for the composition of reliability and process time requirements. Further, two decentralized decision process strategies are proposed based on our framework, and we compare the reliability with the static strategy and the centralized processing strategy. The simulation results show that the one-order feedback strategy has high reliability, scalability and stability against the complexity of decision and random failure. This paper also shows a way to simplify the evaluation for dynamic system by improving the composability and compositionality of the subsystem. Full article

(This article belongs to the Special Issue Models, Systems and Applications for Sensors in Cyber Physical Systems)

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15 pages, 6395 KiB

Open AccessArticle

Label-Free Biomedical Imaging Using High-Speed Lock-In Pixel Sensor for Stimulated Raman Scattering

by Kamel Mars¹

, De Xing Lioe¹

, Shoji Kawahito^1,*, Keita Yasutomi¹, Keiichiro Kagawa¹, Takahiro Yamada^2,3 and Mamoru Hashimoto^3,4

¹ Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Nakaku, Hamamatsu, Shizuoka 432-8011, Japan

² Mitsubishi Electric Corporation Nagoya Works, FA System Manufacturing Department, Manufacturing Engineering Section, 1-14, Yada-minami 5-chome, Higashi-ku, Nagoya, Aichi 461-8670, Japan

³ Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan

⁴ Graduate School of Information Science and Technology, Hokkaido University, Kita 14, Nishi 9, Kita-ku, Sapporo 060-0814, Japan

Sensors 2017, 17(11), 2581; https://doi.org/10.3390/s17112581 - 9 Nov 2017

Cited by 9 | Viewed by 6407

Abstract

Raman imaging eliminates the need for staining procedures, providing label-free imaging to study biological samples. Recent developments in stimulated Raman scattering (SRS) have achieved fast acquisition speed and hyperspectral imaging. However, there has been a problem of lack of detectors suitable for MHz [...] Read more.

Raman imaging eliminates the need for staining procedures, providing label-free imaging to study biological samples. Recent developments in stimulated Raman scattering (SRS) have achieved fast acquisition speed and hyperspectral imaging. However, there has been a problem of lack of detectors suitable for MHz modulation rate parallel detection, detecting multiple small SRS signals while eliminating extremely strong offset due to direct laser light. In this paper, we present a complementary metal-oxide semiconductor (CMOS) image sensor using high-speed lock-in pixels for stimulated Raman scattering that is capable of obtaining the difference of Stokes-on and Stokes-off signal at modulation frequency of 20 MHz in the pixel before reading out. The generated small SRS signal is extracted and amplified in a pixel using a high-speed and large area lateral electric field charge modulator (LEFM) employing two-step ion implantation and an in-pixel pair of low-pass filter, a sample and hold circuit and a switched capacitor integrator using a fully differential amplifier. A prototype chip is fabricated using 0.11 μm CMOS image sensor technology process. SRS spectra and images of stearic acid and 3T3-L1 samples are successfully obtained. The outcomes suggest that hyperspectral and multi-focus SRS imaging at video rate is viable after slight modifications to the pixel architecture and the acquisition system. Full article

(This article belongs to the Section Physical Sensors)

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13 pages, 4481 KiB

Open AccessArticle

Multifunctional Woven Structure Operating as Triboelectric Energy Harvester, Capacitive Tactile Sensor Array, and Piezoresistive Strain Sensor Array

by Kihong Kim¹, Giyoung Song², Cheolmin Park² and Kwang-Seok Yun^1,*

¹ Department of Electronic Engineering, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Korea

² Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea

Sensors 2017, 17(11), 2582; https://doi.org/10.3390/s17112582 - 9 Nov 2017

Cited by 54 | Viewed by 9302

Abstract

This paper presents a power-generating sensor array in a flexible and stretchable form. The proposed device is composed of resistive strain sensors, capacitive tactile sensors, and a triboelectric energy harvester in a single platform. The device is implemented in a woven textile structure [...] Read more.

This paper presents a power-generating sensor array in a flexible and stretchable form. The proposed device is composed of resistive strain sensors, capacitive tactile sensors, and a triboelectric energy harvester in a single platform. The device is implemented in a woven textile structure by using proposed functional threads. A single functional thread is composed of a flexible hollow tube coated with silver nanowires on the outer surface and a conductive silver thread inside the tube. The total size of the device is 60 × 60 mm² having a 5 × 5 array of sensor cell. The touch force in the vertical direction can be sensed by measuring the capacitance between the warp and weft functional threads. In addition, because silver nanowire layers provide piezoresistivity, the strain applied in the lateral direction can be detected by measuring the resistance of each thread. Last, with regard to the energy harvester, the maximum power and power density were measured as 201 μW and 0.48 W/m², respectively, when the device was pushed in the vertical direction. Full article

(This article belongs to the Special Issue Tactile Sensors and Sensing)

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30 pages, 6698 KiB

Open AccessArticle

Real-Time Alpine Measurement System Using Wireless Sensor Networks

by Sami A. Malek^1,*, Francesco Avanzi¹

, Keoma Brun-Laguna²

, Tessa Maurer¹

, Carlos A. Oroza¹, Peter C. Hartsough³, Thomas Watteyne²

and Steven D. Glaser¹

¹ Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720, USA

² French Institute for Research in Computer Science and Automation (Inria), 2 Rue Simone IFF, 75012 Paris, France

³ Department of Land, Air, and Water Resources, University of California, Davis, CA 95616, USA

Sensors 2017, 17(11), 2583; https://doi.org/10.3390/s17112583 - 9 Nov 2017

Cited by 25 | Viewed by 9647

Abstract

Monitoring the snow pack is crucial for many stakeholders, whether for hydro-power optimization, water management or flood control. Traditional forecasting relies on regression methods, which often results in snow melt runoff predictions of low accuracy in non-average years. Existing ground-based real-time measurement systems [...] Read more.

Monitoring the snow pack is crucial for many stakeholders, whether for hydro-power optimization, water management or flood control. Traditional forecasting relies on regression methods, which often results in snow melt runoff predictions of low accuracy in non-average years. Existing ground-based real-time measurement systems do not cover enough physiographic variability and are mostly installed at low elevations. We present the hardware and software design of a state-of-the-art distributed Wireless Sensor Network (WSN)-based autonomous measurement system with real-time remote data transmission that gathers data of snow depth, air temperature, air relative humidity, soil moisture, soil temperature, and solar radiation in physiographically representative locations. Elevation, aspect, slope and vegetation are used to select network locations, and distribute sensors throughout a given network location, since they govern snow pack variability at various scales. Three WSNs were installed in the Sierra Nevada of Northern California throughout the North Fork of the Feather River, upstream of the Oroville dam and multiple powerhouses along the river. The WSNs gathered hydrologic variables and network health statistics throughout the 2017 water year, one of northern Sierra’s wettest years on record. These networks leverage an ultra-low-power wireless technology to interconnect their components and offer recovery features, resilience to data loss due to weather and wildlife disturbances and real-time topological visualizations of the network health. Data show considerable spatial variability of snow depth, even within a 1 km

^{2}

network location. Combined with existing systems, these WSNs can better detect precipitation timing and phase in, monitor sub-daily dynamics of infiltration and surface runoff during precipitation or snow melt, and inform hydro power managers about actual ablation and end-of-season date across the landscape. Full article

(This article belongs to the Special Issue Sensor Networks for Environmental Observations)

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11 pages, 3658 KiB

Open AccessArticle

Mach-Zehnder Interferometer Refractive Index Sensor Based on a Plasmonic Channel Waveguide

by Da Eun Lee, Young Jin Lee, Eunso Shin and Soon-Hong Kwon^*

Department of Physics, Chung-Ang University, Seoul 156-756, Korea

Sensors 2017, 17(11), 2584; https://doi.org/10.3390/s17112584 - 9 Nov 2017

Cited by 19 | Viewed by 5675

Abstract

A Mach-Zehnder interferometer based on a plasmonic channel waveguide is proposed for refractive index sensing. The structure, with a small physical footprint of 20 × 120 μm², achieved a high figure of merit of 294. The cut-off frequency behaviour in the [...] Read more.

A Mach-Zehnder interferometer based on a plasmonic channel waveguide is proposed for refractive index sensing. The structure, with a small physical footprint of 20 × 120 μm², achieved a high figure of merit of 294. The cut-off frequency behaviour in the plasmonic channel waveguide resulted in a flat dispersion curve, which induces a 1.8 times larger change of the propagation constant for the given refractive index change compared with previously reported results. Full article

(This article belongs to the Special Issue Surface Plasmon Resonance Sensing)

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16 pages, 16343 KiB

Open AccessArticle

Textile Pressure Mapping Sensor for Emotional Touch Detection in Human-Robot Interaction

by Bo Zhou^1,*

, Carlos Andres Velez Altamirano²

, Heber Cruz Zurian², Seyed Reza Atefi³, Erik Billing⁴

, Fernando Seoane Martinez^3,5,6 and Paul Lukowicz^1,2

¹ German Research Center for Artificial Intelligence, 67663 Kaiserslautern, Germany

² Department Computer Science, University of Kaiserslautern, 67663 Kaiserslautern, Germany

³ Swedish School of Textiles, University of Borås, 50190 Borås, Sweden

⁴ School of Informatics, University of Skövde, 54128 Skövde, Sweden

⁵ Institute for Clinical Science, Intervention and Technology, Karolinska Institutet, 17177 Stockholm, Sweden

⁶ Department Biomedical Engineering, Karolinska University Hospital, 14186 Stockholm, Sweden

Sensors 2017, 17(11), 2585; https://doi.org/10.3390/s17112585 - 9 Nov 2017

Cited by 19 | Viewed by 11050

Abstract

In this paper, we developed a fully textile sensing fabric for tactile touch sensing as the robot skin to detect human-robot interactions. The sensor covers a 20-by-20 cm

^{2}

area with 400 sensitive points and samples at 50 Hz per point. We defined [...] Read more.

In this paper, we developed a fully textile sensing fabric for tactile touch sensing as the robot skin to detect human-robot interactions. The sensor covers a 20-by-20 cm

^{2}

area with 400 sensitive points and samples at 50 Hz per point. We defined seven gestures which are inspired by the social and emotional interactions of typical people to people or pet scenarios. We conducted two groups of mutually blinded experiments, involving 29 participants in total. The data processing algorithm first reduces the spatial complexity to frame descriptors, and temporal features are calculated through basic statistical representations and wavelet analysis. Various classifiers are evaluated and the feature calculation algorithms are analyzed in details to determine each stage and segments’ contribution. The best performing feature-classifier combination can recognize the gestures with a

93.3 %

accuracy from a known group of participants, and

89.1 %

from strangers. Full article

(This article belongs to the Special Issue Tactile Sensors and Sensing)

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15 pages, 4082 KiB

Open AccessArticle

Highly Selective Polypyrrole MIP-Based Gravimetric and Electrochemical Sensors for Picomolar Detection of Glyphosate

by Zouhour Mazouz¹, Seyfeddine Rahali², Najla Fourati^3,*

, Chouki Zerrouki³

, Nadia Aloui⁴

, Mahamadou Seydou⁵, Nourdin Yaakoubi⁴, Mohamed M. Chehimi⁶

, Ali Othmane⁷ and Rafik Kalfat¹

¹ Institut National de Recherches et d’Analyses Physico-chimiques, Laboratoire Matériaux, Traitement et Analyse, BiotechPole Sidi-Thabet, 2032 Ariana, Tunisia

² Unité de Recherche en Modélisation des Sciences Fondamentales et Didactiques, Université de Tunis El Manar, Tunis, Campus Universitaire Farhat-Hached Tunis, Rommana 1068, Tunisia

³ Cnam, SATIE, UMR CNRS 8029, 292 Rue Saint Martin, 75003 Paris, France

⁴ LAUM, UMR CNRS 6613, Université du Maine, Avenue Olivier Messiaen, 72085 Le Mans CEDEX 9, France

⁵ ITODYS, UMR CNRS 7086, Université Paris Sorbonne Paris Cité, 15 Rue J-A de Baïf, 75013 Paris, France

⁶ CNRS, ICMPE, UMR CNRS 7182, 2-8 rue Henri Dunant, 94320 Thiais, France

⁷ Faculté de Médecine de Monastir, Laboratoire d’Interfaçe et de Matériaux Avancés, Université de Monastir, Av. Avicenne, 5000 Monastir, Tunisia

Sensors 2017, 17(11), 2586; https://doi.org/10.3390/s17112586 - 9 Nov 2017

Cited by 59 | Viewed by 7802

Abstract

There is a global debate and concern about the use of glyphosate (Gly) as an herbicide. New toxicological studies will determine its use in the future under new strict conditions or its replacement by alternative synthetic or natural herbicides. In this context, we [...] Read more.

There is a global debate and concern about the use of glyphosate (Gly) as an herbicide. New toxicological studies will determine its use in the future under new strict conditions or its replacement by alternative synthetic or natural herbicides. In this context, we designed biomimetic polymer sensing layers for the selective molecular recognition of Gly. Towards this end, complementary surface acoustic wave (SAW) and electrochemical sensors were functionalized with polypyrrole (PPy)-imprinted polymer for the selective detection of Gly. Their corresponding limits of detection were on the order of 1 pM, which are among the lowest values ever reported in literature. The relevant dissociation constants between PPy and Gly were estimated at [K_d1 = (0.7 ± 0.3) pM and K_d2 = (1.6 ± 1.4) µM] and [K_d1 = (2.4 ± 0.9) pM and K_d2 = (0.3 ± 0.1) µM] for electrochemical and gravimetric measurements, respectively. Quantum chemical calculations permitted to estimate the interaction energy between Gly and PPy film: ΔE = −145 kJ/mol. Selectivity and competitivity tests were investigated with the most common pesticides. This work conclusively shows that gravimetric and electrochemical results indicate that both MIP-based sensors are perfectly able to detect and distinguish glyphosate without any ambiguity. Full article

(This article belongs to the Special Issue Surface Acoustic Wave and Bulk Acoustic Wave Sensors)

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25 pages, 7483 KiB

Open AccessArticle

An Intelligent Cooperative Visual Sensor Network for Urban Mobility

by Giuseppe Riccardo Leone¹, Davide Moroni^1,*

, Gabriele Pieri¹

, Matteo Petracca¹, Ovidio Salvetti¹, Andrea Azzarà² and Francesco Marino²

¹ Institute of Information Science and Technologies, National Research Council of Italy, 56124, Pisa, Italy

² Scuola Superiore Sant’Anna of Pisa, 56124, Pisa, Italy

Sensors 2017, 17(11), 2588; https://doi.org/10.3390/s17112588 - 10 Nov 2017

Cited by 38 | Viewed by 7849

Abstract

Smart cities are demanding solutions for improved traffic efficiency, in order to guarantee optimal access to mobility resources available in urban areas. Intelligent video analytics deployed directly on board embedded sensors offers great opportunities to gather highly informative data about traffic and transport, [...] Read more.

Smart cities are demanding solutions for improved traffic efficiency, in order to guarantee optimal access to mobility resources available in urban areas. Intelligent video analytics deployed directly on board embedded sensors offers great opportunities to gather highly informative data about traffic and transport, allowing reconstruction of a real-time neat picture of urban mobility patterns. In this paper, we present a visual sensor network in which each node embeds computer vision logics for analyzing in real time urban traffic. The nodes in the network share their perceptions and build a global and comprehensive interpretation of the analyzed scenes in a cooperative and adaptive fashion. This is possible thanks to an especially designed Internet of Things (IoT) compliant middleware which encompasses in-network event composition as well as full support of Machine-2-Machine (M2M) communication mechanism. The potential of the proposed cooperative visual sensor network is shown with two sample applications in urban mobility connected to the estimation of vehicular flows and parking management. Besides providing detailed results of each key component of the proposed solution, the validity of the approach is demonstrated by extensive field tests that proved the suitability of the system in providing a scalable, adaptable and extensible data collection layer for managing and understanding mobility in smart cities. Full article

(This article belongs to the Special Issue Advances in Sensors for Sustainable Smart Cities and Smart Buildings)

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21 pages, 57823 KiB

Open AccessArticle

Full-Body Locomotion Reconstruction of Virtual Characters Using a Single Inertial Measurement Unit

by Christos Mousas

Department of Computer Science, Southern Illinois University, 1230 Lincoln Drive, Mail Code 4511, Carbondale, IL 62901, USA

Sensors 2017, 17(11), 2589; https://doi.org/10.3390/s17112589 - 10 Nov 2017

Cited by 32 | Viewed by 5068

Abstract

This paper presents a method of reconstructing full-body locomotion sequences for virtual characters in real-time, using data from a single inertial measurement unit (IMU). This process can be characterized by its difficulty because of the need to reconstruct a high number of degrees [...] Read more.

This paper presents a method of reconstructing full-body locomotion sequences for virtual characters in real-time, using data from a single inertial measurement unit (IMU). This process can be characterized by its difficulty because of the need to reconstruct a high number of degrees of freedom (DOFs) from a very low number of DOFs. To solve such a complex problem, the presented method is divided into several steps. The user’s full-body locomotion and the IMU’s data are recorded simultaneously. Then, the data is preprocessed in such a way that would be handled more efficiently. By developing a hierarchical multivariate hidden Markov model with reactive interpolation functionality the system learns the structure of the motion sequences. Specifically, the phases of the locomotion sequence are assigned in the higher hierarchical level, and the frame structure of the motion sequences are assigned at the lower hierarchical level. During the runtime of the method, the forward algorithm is used for reconstructing the full-body motion of a virtual character. Firstly, the method predicts the phase where the input motion belongs (higher hierarchical level). Secondly, the method predicts the closest trajectories and their progression and interpolates the most probable of them to reconstruct the virtual character’s full-body motion (lower hierarchical level). Evaluating the proposed method shows that it works on reasonable framerates and minimizes the reconstruction errors compared with previous approaches. Full article

(This article belongs to the Section Physical Sensors)

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24 pages, 1750 KiB

Open AccessArticle

Human Actions Analysis: Templates Generation, Matching and Visualization Applied to Motion Capture of Highly-Skilled Karate Athletes

by Tomasz Hachaj^1,*

, Marcin Piekarczyk¹ and Marek R. Ogiela²

¹ Institute of Computer Science, Pedagogical University of Krakow, 2 Podchorazych Ave, 30-084 Krakow, Poland

² AGH University of Science and Technology, Cryptography and Cognitive Informatics Research Group, 30 Mickiewicza Ave, 30-059 Krakow, Poland

Sensors 2017, 17(11), 2590; https://doi.org/10.3390/s17112590 - 10 Nov 2017

Cited by 47 | Viewed by 8414

Abstract

The aim of this paper is to propose and evaluate the novel method of template generation, matching, comparing and visualization applied to motion capture (kinematic) analysis. To evaluate our approach, we have used motion capture recordings (MoCap) of two highly-skilled black belt karate [...] Read more.

The aim of this paper is to propose and evaluate the novel method of template generation, matching, comparing and visualization applied to motion capture (kinematic) analysis. To evaluate our approach, we have used motion capture recordings (MoCap) of two highly-skilled black belt karate athletes consisting of 560 recordings of various karate techniques acquired with wearable sensors. We have evaluated the quality of generated templates; we have validated the matching algorithm that calculates similarities and differences between various MoCap data; and we have examined visualizations of important differences and similarities between MoCap data. We have concluded that our algorithms works the best when we are dealing with relatively short (2–4 s) actions that might be averaged and aligned with the dynamic time warping framework. In practice, the methodology is designed to optimize the performance of some full body techniques performed in various sport disciplines, for example combat sports and martial arts. We can also use this approach to generate templates or to compare the correct performance of techniques between various top sportsmen in order to generate a knowledge base of reference MoCap videos. The motion template generated by our method can be used for action recognition purposes. We have used the DTW classifier with angle-based features to classify various karate kicks. We have performed leave-one-out action recognition for the Shorin-ryu and Oyama karate master separately. In this case,

100 %

actions were correctly classified. In another experiment, we used templates generated from Oyama master recordings to classify Shorin-ryu master recordings and vice versa. In this experiment, the overall recognition rate was

94.2 %

, which is a very good result for this type of complex action. Full article

(This article belongs to the Section Intelligent Sensors)

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15 pages, 9189 KiB

Open AccessArticle

A Pneumatic Tactile Sensor for Co-Operative Robots

by Daoxiong Gong^1,2,*

, Rui He^1,2, Jianjun Yu^1,2 and Guoyu Zuo^1,2

¹ Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China

² Beijing Key Lab of the Computational Intelligence and Intelligent System, Beijing 100124, China

Sensors 2017, 17(11), 2592; https://doi.org/10.3390/s17112592 - 10 Nov 2017

Cited by 46 | Viewed by 10251

Abstract

Tactile sensors of comprehensive functions are urgently needed for the advanced robot to co-exist and co-operate with human beings. Pneumatic tactile sensors based on air bladder possess some noticeable advantages for human-robot interaction application. In this paper, we construct a pneumatic tactile sensor [...] Read more.

Tactile sensors of comprehensive functions are urgently needed for the advanced robot to co-exist and co-operate with human beings. Pneumatic tactile sensors based on air bladder possess some noticeable advantages for human-robot interaction application. In this paper, we construct a pneumatic tactile sensor and apply it on the fingertip of robot hand to realize the sensing of force, vibration and slippage via the change of the pressure of the air bladder, and we utilize the sensor to perceive the object’s features such as softness and roughness. The pneumatic tactile sensor has good linearity, repeatability and low hysteresis and both its size and sensing range can be customized by using different material as well as different thicknesses of the air bladder. It is also simple and cheap to fabricate. Therefore, the pneumatic tactile sensor is suitable for the application of co-operative robots and can be widely utilized to improve the performance of service robots. We can apply it to the fingertip of the robot to endow the robotic hand with the ability to co-operate with humans and handle the fragile objects because of the inherent compliance of the air bladder. Full article

(This article belongs to the Special Issue Tactile Sensors and Sensing)

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16 pages, 3855 KiB

Open AccessArticle

A Mediated BOD Biosensor Based on Immobilized B. Subtilis on Three-Dimensional Porous Graphene-Polypyrrole Composite

by Jingfang Hu^1,*, Yueqi Li¹, Guowei Gao^1,† and Shanhong Xia^2,†

¹ Key Laboratory of Sensor, Beijing Information Science and Technology University, Beijing 100000, China

² State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Science, Beijing 100000, China

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2594; https://doi.org/10.3390/s17112594 - 10 Nov 2017

Cited by 46 | Viewed by 5970

Abstract

We have developed a novel mediated biochemical oxygen demand (BOD) biosensor based on immobilized Bacillus subtilis (B. subtilis) on three-dimensional (3D) porous graphene-polypyrrole (rGO-PPy) composite. The 3D porous rGO-PPy composite was prepared using hydrothermal method following with electropolymerization. Then the 3D [...] Read more.

We have developed a novel mediated biochemical oxygen demand (BOD) biosensor based on immobilized Bacillus subtilis (B. subtilis) on three-dimensional (3D) porous graphene-polypyrrole (rGO-PPy) composite. The 3D porous rGO-PPy composite was prepared using hydrothermal method following with electropolymerization. Then the 3D porous rGO-PPy composite was used as a support for immobilizing negatively charged B. subtilis denoted as rGO-PPy-B through coordination and electrostatic interaction. Further, the prepared rGO-PPy-B was used as a microbial biofilm for establishing a mediated BOD biosensor with ferricyanide as an electronic acceptor. The indirect determination of BOD was performed by electrochemical measuring ferrocyanide generated from a reduced ferricyanide mediator using interdigited ultramicroelectrode array (IUDA) as the working electrode. The experimental results suggested a good linear relationship between the amperometric responses and BOD standard concentrations from 4 to 60 mg/L, with a limit detection of 1.8 mg/L (S/N ≥ 3). The electrochemical measurement of real water samples showed a good agreement with the conventional BOD₅ method, and the good anti-interference as well as the long-term stability were well demonstrated, indicating that the proposed mediated BOD biosensor in this study holds a potential practical application of real water monitoring. Full article

(This article belongs to the Section Biosensors)

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14 pages, 16607 KiB

Open AccessArticle

Towards Optical Partial Discharge Detection with Micro Silicon Photomultipliers

by Ming Ren^1,*, Jierui Zhou¹

, Bo Song¹, Chongxing Zhang¹

, Ming Dong¹ and Ricardo Albarracín^2,*

¹ State Key Laboratory of Electrical Insulation for Power Equipment, Xi’an Jiaotong University, 28 Xianning West Road, Xi’an 710049, China

² Departamento de Ingeniería Eléctrica, Electrónica, Automática y Física Aplicada, Escuela Técnica Superior de Ingeniería y Diseño Industrial (ETSIDI), Universidad Politécnica de Madrid (UPM), Ronda de Valencia 3, 28012 Madrid, Spain

Sensors 2017, 17(11), 2595; https://doi.org/10.3390/s17112595 - 10 Nov 2017

Cited by 47 | Viewed by 8550

Abstract

Optical detection is reliable in intrinsically characterizing partial discharges (PDs). Because of the great volume and high-level power supply of the optical devices that can satisfy the requirements in photosensitivity, optical PD detection can merely be used in laboratory studies. To promote the [...] Read more.

Optical detection is reliable in intrinsically characterizing partial discharges (PDs). Because of the great volume and high-level power supply of the optical devices that can satisfy the requirements in photosensitivity, optical PD detection can merely be used in laboratory studies. To promote the practical application of the optical approach in an actual power apparatus, a silicon photomultiplier (SiPM)-based PD sensor is introduced in this paper, and its basic properties, which include the sensitivity, pulse resolution, correlation with PD severity, and electromagnetic (EM) interference immunity, are experimentally evaluated. The stochastic phase-resolved PD pattern (PRPD) for three typical insulation defects are obtained by SiPM PD detector and are compared with those obtained using a high-frequency current transformer (HFCT) and a vacuum photomultiplier tube (PMT). Because of its good performances in the above aspects and its additional advantages, such as the small size, low power supply, and low cost, SiPM offers great potential in practical optical PD monitoring. Full article

(This article belongs to the Section Physical Sensors)

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13 pages, 4311 KiB

Open AccessArticle

Cost-Effective and Handmade Paper-Based Immunosensing Device for Electrochemical Detection of Influenza Virus

by Sivaranjani Devarakonda^1,†, Renu Singh^1,†, Jyoti Bhardwaj² and Jaesung Jang^1,2,*

¹ Department of Mechanical Engineering, School of Mechanical, Aerospace and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea

² Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2597; https://doi.org/10.3390/s17112597 - 11 Nov 2017

Cited by 72 | Viewed by 7317

Abstract

Although many studies concerning the detection of influenza virus have been published, a paper-based, label-free electrochemical immunosensor has never been reported. Here, we present a cost-effective, handmade paper-based immunosensor for label-free electrochemical detection of influenza virus H1N1. This immunosensor was prepared by modifying [...] Read more.

Although many studies concerning the detection of influenza virus have been published, a paper-based, label-free electrochemical immunosensor has never been reported. Here, we present a cost-effective, handmade paper-based immunosensor for label-free electrochemical detection of influenza virus H1N1. This immunosensor was prepared by modifying paper with a spray of hydrophobic silica nanoparticles, and using stencil-printed electrodes. We used a glass vaporizer to spray the hydrophobic silica nanoparticles onto the paper, rendering it super-hydrophobic. The super-hydrophobicity, which is essential for this paper-based biosensor, was achieved via 30–40 spray coatings, corresponding to a 0.39–0.41 mg cm⁻² coating of nanoparticles on the paper and yielding a water contact angle of 150° ± 1°. Stencil-printed carbon electrodes modified with single-walled carbon nanotubes and chitosan were employed to increase the sensitivity of the sensor, and the antibodies were immobilized via glutaraldehyde cross-linking. Differential pulse voltammetry was used to assess the sensitivity of the sensors at various virus concentrations, ranging from 10 to 10⁴ PFU mL⁻¹, and the selectivity was assessed against MS2 bacteriophages and the influenza B viruses. These immunosensors showed good linear behaviors, improved detection times (30 min), and selectivity for the H1N1 virus with a limit of detection of 113 PFU mL⁻¹, which is sufficiently sensitive for rapid on-site diagnosis. The simple and inexpensive methodologies developed in this study have great potential to be used for the development of a low-cost and disposable immunosensor for detection of pathogenic microorganisms, especially in developing countries. Full article

(This article belongs to the Section Biosensors)

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8 pages, 682 KiB

Open AccessArticle

Design and Evaluation of Novel Polymyxin Fluorescent Probes

by Bo Yun¹, Kade D. Roberts¹, Philip E. Thompson²

, Roger L. Nation¹, Tony Velkov^1,*

and Jian Li^3,*

¹ Drug Delivery, Disposition and Dynamics, Monash University, Parkville, Victoria 3052, Australia

² Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia

³ Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia

Sensors 2017, 17(11), 2598; https://doi.org/10.3390/s17112598 - 11 Nov 2017

Cited by 10 | Viewed by 4621

Abstract

Polymyxins (polymyxin B and colistin) are cyclic lipopeptide antibiotics that serve as a last-line defence against Gram-negative “superbugs”. In the present study, two novel fluorescent polymyxin probes were designed through regio-selective modifications of the polymyxin B core structure at the N-terminus and [...] Read more.

Polymyxins (polymyxin B and colistin) are cyclic lipopeptide antibiotics that serve as a last-line defence against Gram-negative “superbugs”. In the present study, two novel fluorescent polymyxin probes were designed through regio-selective modifications of the polymyxin B core structure at the N-terminus and the hydrophobic motif at positions 6 and 7. The resulting probes, FADDI-285 and FADDI-286 demonstrated comparable antibacterial activity (MICs 2–8 mg/L) to polymyxin B and colistin (MICs 0.5–8 mg/L) against a panel of gram-negative clinical isolates of Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa. These probes should prove to be of considerable utility for imaging cellular uptake and mechanistic investigations of these important last-line antibiotics. Full article

(This article belongs to the Special Issue Fluorescent Probes and Sensors)

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24 pages, 6173 KiB

Open AccessArticle

A Comparison of FPGA and GPGPU Designs for Bayesian Occupancy Filters

by Luis Medina¹, Miguel Diez-Ochoa², Raul Correal², Sergio Cuenca-Asensi¹, Alejandro Serrano¹

, Jorge Godoy³, Antonio Martínez-Álvarez¹ and Jorge Villagra^3,*

¹ University Institute for Computing Research, University of Alicante, 03690 San Vicente del Raspeig, Spain

² Ixion Industry & Aerospace SL, Julian Camarilo 21B, 28037 Madrid, Spain

³ Centre for Automation and Robotics (UPM-CSIC), 28500 Arganda del Rey, Spain

Sensors 2017, 17(11), 2599; https://doi.org/10.3390/s17112599 - 11 Nov 2017

Cited by 3 | Viewed by 4390

Abstract

Grid-based perception techniques in the automotive sector based on fusing information from different sensors and their robust perceptions of the environment are proliferating in the industry. However, one of the main drawbacks of these techniques is the traditionally prohibitive, high computing performance that [...] Read more.

Grid-based perception techniques in the automotive sector based on fusing information from different sensors and their robust perceptions of the environment are proliferating in the industry. However, one of the main drawbacks of these techniques is the traditionally prohibitive, high computing performance that is required for embedded automotive systems. In this work, the capabilities of new computing architectures that embed these algorithms are assessed in a real car. The paper compares two ad hoc optimized designs of the Bayesian Occupancy Filter; one for General Purpose Graphics Processing Unit (GPGPU) and the other for Field-Programmable Gate Array (FPGA). The resulting implementations are compared in terms of development effort, accuracy and performance, using datasets from a realistic simulator and from a real automated vehicle. Full article

(This article belongs to the Section Physical Sensors)

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11 pages, 4286 KiB

Open AccessArticle

Incorporation of Fiber Bragg Sensors for Shape Memory Polyurethanes Characterization

by Nélia Alberto^1,2,*,†

, Maria A. Fonseca^3,†

, Victor Neto²

, Rogério Nogueira¹, Mónica Oliveira³

and Rui Moreira³

¹ Instituto de Telecomunicações, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal

² NRG-Research Group, Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal

³ GRIDS-Research Group, Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2600; https://doi.org/10.3390/s17112600 - 11 Nov 2017

Cited by 6 | Viewed by 4601

Abstract

Shape memory polyurethanes (SMPUs) are thermally activated shape memory materials, which can be used as actuators or sensors in applications including aerospace, aeronautics, automobiles or the biomedical industry. The accurate characterization of the memory effect of these materials is therefore mandatory for the [...] Read more.

Shape memory polyurethanes (SMPUs) are thermally activated shape memory materials, which can be used as actuators or sensors in applications including aerospace, aeronautics, automobiles or the biomedical industry. The accurate characterization of the memory effect of these materials is therefore mandatory for the technology’s success. The shape memory characterization is normally accomplished using mechanical testing coupled with a heat source, where a detailed knowledge of the heat cycle and its influence on the material properties is paramount but difficult to monitor. In this work, fiber Bragg grating (FBG) sensors were embedded into SMPU samples aiming to study and characterize its shape memory effect. The samples were obtained by injection molding, and the entire processing cycle was successfully monitored, providing a process global quality signature. Moreover, the integrity and functionality of the FBG sensors were maintained during and after the embedding process, demonstrating the feasibility of the technology chosen for the purpose envisaged. The results of the shape memory effect characterization demonstrate a good correlation between the reflected FBG peak with the temperature and induced strain, proving that this technology is suitable for this particular application. Full article

(This article belongs to the Special Issue Fiber Bragg Grating Based Sensors)

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14 pages, 14407 KiB

Open AccessArticle

Tactile Evaluation Feedback System for Multi-Layered Structure Inspired by Human Tactile Perception Mechanism

by Iza Husna Mohamad Hashim¹, Shogo Kumamoto¹, Kenjiro Takemura^2,*

, Takashi Maeno³, Shin Okuda⁴ and Yukio Mori⁴

¹ Graduate School of Science and Technology, Keio University, Yokohama 223-8522, Japan

² Department of Mechanical Engineering, Keio University, Yokohama 223-8522, Japan

³ Graduate School of System Design and Management, Keio University, Yokohama 223-8526, Japan

⁴ NANJO Auto Interior Co., Ltd., Hiroshima 732-0806, Japan

Sensors 2017, 17(11), 2601; https://doi.org/10.3390/s17112601 - 11 Nov 2017

Cited by 33 | Viewed by 8316

Abstract

Tactile sensation is one type of valuable feedback in evaluating a product. Conventionally, sensory evaluation is used to get direct subjective responses from the consumers, in order to improve the product’s quality. However, this method is a time-consuming and costly process. Therefore, this [...] Read more.

Tactile sensation is one type of valuable feedback in evaluating a product. Conventionally, sensory evaluation is used to get direct subjective responses from the consumers, in order to improve the product’s quality. However, this method is a time-consuming and costly process. Therefore, this paper proposes a novel tactile evaluation system that can give tactile feedback from a sensor’s output. The main concept of this system is hierarchically layering the tactile sensation, which is inspired by the flow of human perception. The tactile sensation is classified from low-order of tactile sensation (LTS) to high-order of tactile sensation (HTS), and also to preference. Here, LTS will be correlated with physical measures. Furthermore, the physical measures that are used to correlate with LTS are selected based on four main aspects of haptic information (roughness, compliance, coldness, and slipperiness), which are perceived through human tactile sensors. By using statistical analysis, the correlation between each hierarchy was obtained, and the preference was derived in terms of physical measures. A verification test was conducted by using unknown samples to determine the reliability of the system. The results showed that the system developed was capable of estimating preference with an accuracy of approximately 80%. Full article

(This article belongs to the Special Issue Tactile Sensors and Sensing)

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10 pages, 5969 KiB

Open AccessArticle

A Miniaturized Nickel Oxide Thermistor via Aerosol Jet Technology

by Chia Wang^*, Guan-Yi Hong

, Kuan-Ming Li and Hong-Tsu Young

Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan

Sensors 2017, 17(11), 2602; https://doi.org/10.3390/s17112602 - 12 Nov 2017

Cited by 33 | Viewed by 6537

Abstract

In this study, a miniaturized thermistor sensor was produced using the Aerosol Jet printing process for temperature sensing applications. A nickel oxide nanoparticle ink with a large temperature coefficient of resistance was fabricated. The thermistor was printed with a circular NiO thin film [...] Read more.

In this study, a miniaturized thermistor sensor was produced using the Aerosol Jet printing process for temperature sensing applications. A nickel oxide nanoparticle ink with a large temperature coefficient of resistance was fabricated. The thermistor was printed with a circular NiO thin film in between the two parallel silver conductive tracks on a cutting tool insert. The printed thermistor, which has an adjustable dimension with a submillimeter scale, operates over a range of 30–250 °C sensitively (B value of ~4310 K) without hysteretic effects. Moreover, the thermistor may be printed on a 3D surface through the Aerosol Jet printing process, which has increased capability for wide temperature-sensing applications. Full article

(This article belongs to the Special Issue Mechatronic Systems for Automatic Vehicles)

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15 pages, 10070 KiB

Open AccessArticle

Linear vs. Nonlinear Extreme Learning Machine for Spectral-Spatial Classification of Hyperspectral Images

by Faxian Cao¹

, Zhijing Yang^1,*

, Jinchang Ren², Mengying Jiang¹ and Wing-Kuen Ling¹

¹ School of Information Engineering, Guangdong University of Technology, Guangzhou 510006, China

² Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow G1 1XW, UK

Sensors 2017, 17(11), 2603; https://doi.org/10.3390/s17112603 - 13 Nov 2017

Cited by 22 | Viewed by 4185

Abstract

As a new machine learning approach, the extreme learning machine (ELM) has received much attention due to its good performance. However, when directly applied to hyperspectral image (HSI) classification, the recognition rate is low. This is because ELM does not use spatial information, [...] Read more.

As a new machine learning approach, the extreme learning machine (ELM) has received much attention due to its good performance. However, when directly applied to hyperspectral image (HSI) classification, the recognition rate is low. This is because ELM does not use spatial information, which is very important for HSI classification. In view of this, this paper proposes a new framework for the spectral-spatial classification of HSI by combining ELM with loopy belief propagation (LBP). The original ELM is linear, and the nonlinear ELMs (or Kernel ELMs) are an improvement of linear ELM (LELM). However, based on lots of experiments and much analysis, it is found that the LELM is a better choice than nonlinear ELM for the spectral-spatial classification of HSI. Furthermore, we exploit the marginal probability distribution that uses the whole information in the HSI and learns such a distribution using the LBP. The proposed method not only maintains the fast speed of ELM, but also greatly improves the accuracy of classification. The experimental results in the well-known HSI data sets, Indian Pines, and Pavia University, demonstrate the good performance of the proposed method. Full article

(This article belongs to the Section Remote Sensors)

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29 pages, 972 KiB

Open AccessArticle

Wireless Energy Harvesting Two-Way Relay Networks with Hardware Impairments

by Chunling Peng¹, Fangwei Li^1,* and Huaping Liu²

¹ Chongqing Key Lab of Mobile Communications Technology, Chongqing University of Posts and Telecommunications, Chongqing 400065, China

² School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331, USA

Sensors 2017, 17(11), 2604; https://doi.org/10.3390/s17112604 - 13 Nov 2017

Cited by 13 | Viewed by 5353

Abstract

This paper considers a wireless energy harvesting two-way relay (TWR) network where the relay has energy-harvesting abilities and the effects of practical hardware impairments are taken into consideration. In particular, power splitting (PS) receiver is adopted at relay to harvests the power it [...] Read more.

This paper considers a wireless energy harvesting two-way relay (TWR) network where the relay has energy-harvesting abilities and the effects of practical hardware impairments are taken into consideration. In particular, power splitting (PS) receiver is adopted at relay to harvests the power it needs for relaying the information between the source nodes from the signals transmitted by the source nodes, and hardware impairments is assumed suffered by each node. We analyze the effect of hardware impairments on both decode-and-forward (DF) relaying and amplify-and-forward (AF) relaying networks. By utilizing the obtained new expressions of signal-to-noise-plus-distortion ratios, the exact analytical expressions of the achievable sum rate and ergodic capacities for both DF and AF relaying protocols are derived. Additionally, the optimal power splitting (OPS) ratio that maximizes the instantaneous achievable sum rate is formulated and solved for both protocols. The performances of DF and AF protocols are evaluated via numerical results, which also show the effects of various network parameters on the system performance and on the OPS ratio design. Full article

(This article belongs to the Special Issue Wireless Rechargeable Sensor Networks)

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20 pages, 6789 KiB

Open AccessArticle

Water-Based Suspensions of Iron Oxide Nanoparticles with Electrostatic or Steric Stabilization by Chitosan: Fabrication, Characterization and Biocompatibility

by Galina V. Kurlyandskaya^1,2,*

, Larisa S. Litvinova³

, Alexander P. Safronov^2,4, Valeria V. Schupletsova³, Irina S. Tyukova², Olga G. Khaziakhmatova³, Galina B. Slepchenko⁵, Kristina A. Yurova³, Elena G. Cherempey⁵, Nikita A. Kulesh², Ricardo Andrade⁶, Igor V. Beketov⁴ and Igor A. Khlusov^3,7

¹ Departamento de Electricidad y Electrónica and BCMaterials, Universidad del País Vasco UPV-EHU, 48080 Bilbao, Spain

² Institute of Natural Sciences and Mathematics, Ural Federal University, Ekaterinburg 620002, Russia

³ Laboratory of Immunology and Cell Biotechnology, I. Kant Baltic Federal University, Kaliningrad 23601, Russia

⁴ Institute of Electrophysics, Ural Division RAS, Ekaterinburg 620016, Russia

⁵ Department of Physical and Analytical Chemistry, National Research Tomsk Polytechnic University, Tomsk 634050, Russia

⁶ Advanced Research Facilities (SGIKER), Universidad del País Vasco UPV-EHU, 48080 Bilbao, Spain

⁷ Department of Experimental Physics, National Research Tomsk Polytechnic University, Tomsk 634050, Russia

Sensors 2017, 17(11), 2605; https://doi.org/10.3390/s17112605 - 13 Nov 2017

Cited by 31 | Viewed by 6958

Abstract

Present day biomedical applications, including magnetic biosensing, demand better understanding of the interactions between living systems and magnetic nanoparticles (MNPs). In this work spherical MNPs of maghemite were obtained by a highly productive laser target evaporation technique. XRD analysis confirmed the inverse spinel [...] Read more.

Present day biomedical applications, including magnetic biosensing, demand better understanding of the interactions between living systems and magnetic nanoparticles (MNPs). In this work spherical MNPs of maghemite were obtained by a highly productive laser target evaporation technique. XRD analysis confirmed the inverse spinel structure of the MNPs (space group Fd-3m). The ensemble obeyed a lognormal size distribution with the median value 26.8 nm and dispersion 0.362. Stabilized water-based suspensions were fabricated using electrostatic or steric stabilization by the natural polymer chitosan. The encapsulation of the MNPs by chitosan makes them resistant to the unfavorable factors for colloidal stability typically present in physiological conditions such as pH and high ionic force. Controlled amounts of suspensions were used for in vitro experiments with human blood mononuclear leukocytes (HBMLs) in order to study their morphofunctional response. For sake of comparison the results obtained in the present study were analyzed together with our previous results of the study of similar suspensions with human mesenchymal stem cells. Suspensions with and without chitosan enhanced the secretion of cytokines by a 24-h culture of HBMLs compared to a control without MNPs. At a dose of 2.3, the MTD of chitosan promotes the stimulating effect of MNPs on cells. In the dose range of MNPs 10–1000 MTD, chitosan “inhibits” cellular secretory activity compared to MNPs without chitosan. Both suspensions did not caused cell death by necrosis, hence, the secretion of cytokines is due to the enhancement of the functional activity of HBMLs. Increased accumulation of MNP with chitosan in the cell fraction at 100 MTD for 24 h exposure, may be due to fixation of chitosan on the outer membrane of HBMLs. The discussed results can be used for an addressed design of cell delivery/removal incorporating multiple activities because of cell capability to avoid phagocytosis by immune cells. They are also promising for the field of biosensor development for the detection of magnetic labels. Full article

(This article belongs to the Special Issue Magnetic Materials Based Biosensors)

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19 pages, 1173 KiB

Open AccessArticle

ABS-FishCount: An Agent-Based Simulator of Underwater Sensors for Measuring the Amount of Fish

by Iván García-Magariño^1,2,*

, Raquel Lacuesta^1,2

and Jaime Lloret³

¹ Department of Computer Science and Engineering of Systems, University of Zaragoza, 44003 Teruel, Spain

² Instituto de Investigación Sanitaria Aragón, University of Zaragoza, 50009 Zaragoza, Spain

³ Integrated Management Coastal Research Institute, Universitat Politècnica de València, 46022 València, Spain

Sensors 2017, 17(11), 2606; https://doi.org/10.3390/s17112606 - 13 Nov 2017

Cited by 10 | Viewed by 4604

Abstract

Underwater sensors provide one of the possibilities to explore oceans, seas, rivers, fish farms and dams, which all together cover most of our planet’s area. Simulators can be helpful to test and discover some possible strategies before implementing these in real underwater sensors. [...] Read more.

Underwater sensors provide one of the possibilities to explore oceans, seas, rivers, fish farms and dams, which all together cover most of our planet’s area. Simulators can be helpful to test and discover some possible strategies before implementing these in real underwater sensors. This speeds up the development of research theories so that these can be implemented later. In this context, the current work presents an agent-based simulator for defining and testing strategies for measuring the amount of fish by means of underwater sensors. The current approach is illustrated with the definition and assessment of two strategies for measuring fish. One of these two corresponds to a simple control mechanism, while the other is an experimental strategy and includes an implicit coordination mechanism. The experimental strategy showed a statistically significant improvement over the control one in the reduction of errors with a large Cohen’s d effect size of 2.55. Full article

(This article belongs to the Section Physical Sensors)

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12 pages, 6270 KiB

Open AccessArticle

A Lab-on-a-Chip-Based Non-Invasive Optical Sensor for Measuring Glucose in Saliva

by Dong Geon Jung^1,†, Daewoong Jung^2,† and Seong Ho Kong^1,*

¹ Graduate School of Electronics Engineering, Kyungpook National University, Daegu 41566, Korea

² Aircraft System Technology Group, Korea Institute of Industrial Technology (KITECH), Daegu 42994, Korea

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2607; https://doi.org/10.3390/s17112607 - 13 Nov 2017

Cited by 57 | Viewed by 10788

Abstract

A lab-on-a-chip (LOC)-based non-invasive optical sensor for measuring glucose in saliva was fabricated. Existing glucose sensors utilizing blood require acquisition of a blood sample by pricking the finger, which is painful and inconvenient. To overcome these limitations, we propose a non-invasive glucose sensor [...] Read more.

A lab-on-a-chip (LOC)-based non-invasive optical sensor for measuring glucose in saliva was fabricated. Existing glucose sensors utilizing blood require acquisition of a blood sample by pricking the finger, which is painful and inconvenient. To overcome these limitations, we propose a non-invasive glucose sensor with LOC, micro-electro-mechanical system and optical measurement technology. The proposed sensor for measuring glucose in saliva involves pretreatment, mixing, and measurement on a single tiny chip. Saliva containing glucose and glucose oxidase for glucose oxidation are injected through Inlets 1 and 2, respectively. Next, H₂O₂ is produced by the reaction between glucose and glucose oxidase in the pretreatment part. The saliva and generated H₂O₂ are mixed with a colorizing agent injected through Inlet 3 during the mixing part and the absorbance of the colorized mixture is measured in the measurement part. The absorbance of light increases as a function of glucose concentration at a wavelength of 630 nm. To measure the absorbance of the colorized saliva, a light-emitting diode with a wavelength of 630 nm and a photodiode were used during the measurement part. As a result, the measured output current of the photodiode decreased as glucose concentration in the saliva increased. Full article

(This article belongs to the Special Issue Optical Biochemical Sensor Systems and Applications)

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31 pages, 7822 KiB

Open AccessArticle

Enhancing the Trajectory Generation of a Stair-Climbing Mobility System

by Jose Abel Chocoteco¹, Rafael Morales^2,* and Vicente Feliu-Batlle³

¹ Instituto Tecnológico de Ciudad Guzmán (ITCG), Tecnológico Nacional de México (TecNM), Ciudad Guzmán 49100, Mexico

² School of Industrial Engineering, University of Castilla-La Mancha (UCLM), 02071 Albacete, Spain

³ School of Industrial Engineering, University of Castilla-La Mancha (UCLM), 13071 Ciudad Real, Spain

Sensors 2017, 17(11), 2608; https://doi.org/10.3390/s17112608 - 13 Nov 2017

Cited by 11 | Viewed by 7886

Abstract

Recent advances in mobile robotic technologies have enabled significant progress to be made in the development of Stair-Climbing Mobility Systems (SCMSs) for people with mobility impairments and limitations. These devices are mainly characterized by their ability to negotiate those architectural barriers associated with [...] Read more.

Recent advances in mobile robotic technologies have enabled significant progress to be made in the development of Stair-Climbing Mobility Systems (SCMSs) for people with mobility impairments and limitations. These devices are mainly characterized by their ability to negotiate those architectural barriers associated with climbing stairs (curbs, ramps, etc.). The development of advanced trajectory generators with which to surpass such architectural barriers is one of the most important aspects of SCMSs that has not yet been appropriately exploited. These advanced trajectory generators have a considerable influence on the time invested in the stair climbing process and on passenger comfort and, consequently, provide people with physical disabilities with greater independence and a higher quality of life. In this paper, we propose a new nonlinear trajectory generator for an SCMS. This generator balances the stair-climbing time and the user’s comfort and includes the most important constraints inherent to the system behavior: the geometry of the architectural barrier, the reconfigurable nature of the SCMS (discontinuous states), SCMS state-transition diagrams, comfort restrictions and physical limitations as regards the actuators, speed and acceleration. The SCMS was tested on a real two-step staircase using different time-comfort combinations and different climbing strategies to verify the effectiveness and the robustness of the proposed approach. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Spain 2017)

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15 pages, 3742 KiB

Open AccessArticle

Highly Efficient Multi Channel Packet Forwarding with Round Robin Intermittent Periodic Transmit for Multihop Wireless Backhaul Networks

by Kazuki Maruta^1,*

and Hiroshi Furukawa²

¹ Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan

² Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan

Sensors 2017, 17(11), 2609; https://doi.org/10.3390/s17112609 - 13 Nov 2017

Cited by 6 | Viewed by 4499

Abstract

Round Robin based Intermittent Periodic Transmit (RR-IPT) has been proposed which achieves highly efficient multi-hop relays in multi-hop wireless backhaul networks (MWBN) where relay nodes are 2-dimensionally deployed. This paper newly investigates multi-channel packet scheduling and forwarding scheme for RR-IPT. Downlink traffic is [...] Read more.

Round Robin based Intermittent Periodic Transmit (RR-IPT) has been proposed which achieves highly efficient multi-hop relays in multi-hop wireless backhaul networks (MWBN) where relay nodes are 2-dimensionally deployed. This paper newly investigates multi-channel packet scheduling and forwarding scheme for RR-IPT. Downlink traffic is forwarded by RR-IPT via one of the channels, while uplink traffic and part of downlink are accommodated in the other channel. By comparing IPT and carrier sense multiple access with collision avoidance (CSMA/CA) for uplink/downlink packet forwarding channel, IPT is more effective in reducing packet loss rate whereas CSMA/CA is better in terms of system throughput and packet delay improvement. Full article

(This article belongs to the Section Sensor Networks)

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23 pages, 10557 KiB

Open AccessArticle

Integrated Display and Simulation for Automatic Dependent Surveillance–Broadcast and Traffic Collision Avoidance System Data Fusion

by Yanran Wang, Gang Xiao^* and Zhouyun Dai

School of Aeronautics and Astronautics, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240, China

Sensors 2017, 17(11), 2611; https://doi.org/10.3390/s17112611 - 13 Nov 2017

Cited by 6 | Viewed by 7821

Abstract

Automatic Dependent Surveillance–Broadcast (ADS-B) is the direction of airspace surveillance development. Research analyzing the benefits of Traffic Collision Avoidance System (TCAS) and ADS-B data fusion is almost absent. The paper proposes an ADS-B minimum system from ADS-B In and ADS-B Out. In ADS-B [...] Read more.

Automatic Dependent Surveillance–Broadcast (ADS-B) is the direction of airspace surveillance development. Research analyzing the benefits of Traffic Collision Avoidance System (TCAS) and ADS-B data fusion is almost absent. The paper proposes an ADS-B minimum system from ADS-B In and ADS-B Out. In ADS-B In, a fusion model with a variable sampling Variational Bayesian-Interacting Multiple Model (VSVB-IMM) algorithm is proposed for integrated display and an airspace traffic situation display is developed by using ADS-B information. ADS-B Out includes ADS-B Out transmission based on a simulator platform and an Unmanned Aerial Vehicle (UAV) platform. This paper describes the overall implementation of ADS-B minimum system, including theoretical model design, experimental simulation verification, engineering implementation, results analysis, etc. Simulation and implementation results show that the fused system has better performance than each independent subsystem and it can work well in engineering applications. Full article

(This article belongs to the Special Issue Advances in Multi-Sensor Information Fusion: Theory and Applications 2017)

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11 pages, 3263 KiB

Open AccessArticle

Gas Measurement Using Static Fourier Transform Infrared Spectrometers

by Michael H. Köhler^*

, Michael Schardt, Markus S. Rauscher and Alexander W. Koch

Institute for Measurement Systems and Sensor Technology, Technical University of Munich, 80333 Munich, Germany

Sensors 2017, 17(11), 2612; https://doi.org/10.3390/s17112612 - 13 Nov 2017

Cited by 21 | Viewed by 6206

Abstract

Online monitoring of gases in industrial processes is an ambitious task due to adverse conditions such as mechanical vibrations and temperature fluctuations. Whereas conventional Fourier transform infrared (FTIR) spectrometers use rather complex optical and mechanical designs to ensure stable operation, static FTIR spectrometers [...] Read more.

Online monitoring of gases in industrial processes is an ambitious task due to adverse conditions such as mechanical vibrations and temperature fluctuations. Whereas conventional Fourier transform infrared (FTIR) spectrometers use rather complex optical and mechanical designs to ensure stable operation, static FTIR spectrometers do not require moving parts and thus offer inherent stability at comparatively low costs. Therefore, we present a novel, compact gas measurement system using a static single-mirror Fourier transform spectrometer (sSMFTS). The system works in the mid-infrared range from 650 cm

^{- 1}

to 1250 cm

^{- 1}

and can be operated with a customized White cell, yielding optical path lengths of up to 120 cm for highly sensitive quantification of gas concentrations. To validate the system, we measure different concentrations of 1,1,1,2-Tetrafluoroethane (R134a) and perform a PLS regression analysis of the acquired infrared spectra. Thereby, the measured absorption spectra show good agreement with reference data. Since the system additionally permits measurement rates of up to 200 Hz and high signal-to-noise ratios, an application in process analysis appears promising. Full article

(This article belongs to the Section Chemical Sensors)

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25 pages, 5221 KiB

Open AccessArticle

Monocular Visual-Inertial SLAM: Continuous Preintegration and Reliable Initialization

by Yi Liu¹, Zhong Chen^1,*, Wenjuan Zheng², Hao Wang² and Jianguo Liu¹

¹ National Key Laboratory of Science and Technology on Multi-Spectral Information Processing, School of Automation, Huazhong University of Science and Technology, Wuhan 430074, China

² Beijing Aerospace Automatic Control Institute, Beijing 100854, China

Sensors 2017, 17(11), 2613; https://doi.org/10.3390/s17112613 - 14 Nov 2017

Cited by 20 | Viewed by 7039

Abstract

In this paper, we propose a new visual-inertial Simultaneous Localization and Mapping (SLAM) algorithm. With the tightly coupled sensor fusion of a global shutter monocular camera and a low-cost Inertial Measurement Unit (IMU), this algorithm is able to achieve robust and real-time estimates [...] Read more.

In this paper, we propose a new visual-inertial Simultaneous Localization and Mapping (SLAM) algorithm. With the tightly coupled sensor fusion of a global shutter monocular camera and a low-cost Inertial Measurement Unit (IMU), this algorithm is able to achieve robust and real-time estimates of the sensor poses in unknown environment. To address the real-time visual-inertial fusion problem, we present a parallel framework with a novel IMU initialization method. Our algorithm also benefits from the novel IMU factor, the continuous preintegration method, the vision factor of directional error, the separability trick and the robust initialization criterion which can efficiently output reliable estimates in real-time on modern Central Processing Unit (CPU). Tremendous experiments also validate the proposed algorithm and prove it is comparable to the state-of-art method. Full article

(This article belongs to the Special Issue Imaging Depth Sensors—Sensors, Algorithms and Applications)

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15 pages, 5028 KiB

Open AccessArticle

Sensitivity to Heavy-Metal Ions of Unfolded Fullerene Quantum Dots

by Erica Ciotta¹, Stefano Paoloni¹, Maria Richetta¹, Paolo Prosposito²

, Pietro Tagliatesta³

, Chiara Lorecchio³, Iole Venditti⁴

, Ilaria Fratoddi⁴

, Stefano Casciardi⁵

and Roberto Pizzoferrato^1,*

¹ Department of Industrial Engineering, University of Rome Tor Vergata, 00133 Rome, Italy

² Department of Industrial Engineering INSTM and CiMER, University of Rome Tor Vergata, 00133 Rome, Italy

³ Department of Chemical Sciences and Technology, University of Rome Tor Vergata, 00133 Rome, Italy

⁴ Department of Chemistry, University of Rome Sapienza, 00187 Rome, Italy

⁵ National Institute for Insurance against Accidents at Work (INAIL), Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, 00078 Monte Porzio Catone, 00133 Rome, Italy

Sensors 2017, 17(11), 2614; https://doi.org/10.3390/s17112614 - 14 Nov 2017

Cited by 48 | Viewed by 7517

Abstract

A novel type of graphene-like quantum dots, synthesized by oxidation and cage-opening of C₆₀ buckminsterfullerene, has been studied as a fluorescent and absorptive probe for heavy-metal ions. The lattice structure of such unfolded fullerene quantum dots (UFQDs) is distinct from that of [...] Read more.

A novel type of graphene-like quantum dots, synthesized by oxidation and cage-opening of C₆₀ buckminsterfullerene, has been studied as a fluorescent and absorptive probe for heavy-metal ions. The lattice structure of such unfolded fullerene quantum dots (UFQDs) is distinct from that of graphene since it includes both carbon hexagons and pentagons. The basic optical properties, however, are similar to those of regular graphene oxide quantum dots. On the other hand, UFQDs behave quite differently in the presence of heavy-metal ions, in that multiple sensitivity to Cu²⁺, Pb²⁺ and As(III) was observed through comparable quenching of the fluorescent emission and different variations of the transmittance spectrum. By dynamic light scattering measurements and transmission electron microscope (TEM) images we confirmed, for the first time in metal sensing, that this response is due to multiple complexation and subsequent aggregation of UFQDs. Nonetheless, the explanation of the distinct behaviour of transmittance in the presence of As(III) and the formation of precipitate with Pb²⁺ require further studies. These differences, however, also make it possible to discriminate between the three metal ions in view of the implementation of a selective multiple sensor. Full article

(This article belongs to the Special Issue Sensors Based on Quantum Phenomena)

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15 pages, 660 KiB

Open AccessArticle

Circular Regression in a Dual-Phase Lock-In Amplifier for Coherent Detection of Weak Signal

by Gaoxuan Wang¹, Serge Reboul^2,*, Jean-Bernard Choquel²

, Eric Fertein¹ and Weidong Chen^1,*

¹ Laboratoire de Physico-Chimie de l’Atmosphère, Université du Littoral Côte d’Opale, 59140 Dnkerque, France

² Laboratoire d’Informatique, Signal et Image de la Côte d’Opale (LISIC), Université du Littoral Côte d’Opale, 62228 Calais, France

Sensors 2017, 17(11), 2615; https://doi.org/10.3390/s17112615 - 14 Nov 2017

Cited by 12 | Viewed by 3977

Abstract

Lock-in amplification (LIA) is an effective approach for recovery of weak signal buried in noise. Determination of the input signal amplitude in a classical dual-phase LIA is based on incoherent detection which leads to a biased estimation at low signal-to-noise ratio. This article [...] Read more.

Lock-in amplification (LIA) is an effective approach for recovery of weak signal buried in noise. Determination of the input signal amplitude in a classical dual-phase LIA is based on incoherent detection which leads to a biased estimation at low signal-to-noise ratio. This article presents, for the first time to our knowledge, a new architecture of LIA involving phase estimation with a linear-circular regression for coherent detection. The proposed phase delay estimate, between the input signal and a reference, is defined as the maximum-likelihood of a set of observations distributed according to a von Mises distribution. In our implementation this maximum is obtained with a Newton Raphson algorithm. We show that the proposed LIA architecture provides an unbiased estimate of the input signal amplitude. Theoretical simulations with synthetic data demonstrate that the classical LIA estimates are biased for SNR of the input signal lower than −20 dB, while the proposed LIA is able to accurately recover the weak signal amplitude. The novel approach is applied to an optical sensor for accurate measurement of NO

_{2}

concentrations at the sub-ppbv level in the atmosphere. Side-by-side intercomparison measurements with a commercial LIA (SR830, Stanford Research Inc., Sunnyvale, CA, USA ) demonstrate that the proposed LIA has an identical performance in terms of measurement accuracy and precision but with simplified hardware architecture. Full article

(This article belongs to the Section Physical Sensors)

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11 pages, 3284 KiB

Open AccessArticle

A Digital Microfluidics Platform for Loop-Mediated Isothermal Amplification Detection

by Beatriz Jorge Coelho^1,2,†

, Bruno Veigas^1,2,†, Hugo Águas¹

, Elvira Fortunato¹, Rodrigo Martins¹

, Pedro Viana Baptista^2,* and Rui Igreja^1,*

¹ CENIMAT|i3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal

² UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2616; https://doi.org/10.3390/s17112616 - 16 Nov 2017

Cited by 38 | Viewed by 9261

Abstract

Digital microfluidics (DMF) arises as the next step in the fast-evolving field of operation platforms for molecular diagnostics. Moreover, isothermal schemes, such as loop-mediated isothermal amplification (LAMP), allow for further simplification of amplification protocols. Integrating DMF with LAMP will be at the core [...] Read more.

Digital microfluidics (DMF) arises as the next step in the fast-evolving field of operation platforms for molecular diagnostics. Moreover, isothermal schemes, such as loop-mediated isothermal amplification (LAMP), allow for further simplification of amplification protocols. Integrating DMF with LAMP will be at the core of a new generation of detection devices for effective molecular diagnostics at point-of-care (POC), providing simple, fast, and automated nucleic acid amplification with exceptional integration capabilities. Here, we demonstrate for the first time the role of coupling DMF and LAMP, in a dedicated device that allows straightforward mixing of LAMP reagents and target DNA, as well as optimum temperature control (reaction droplets undergo a temperature variation of just 0.3 °C, for 65 °C at the bottom plate). This device is produced using low-temperature and low-cost production processes, adaptable to disposable and flexible substrates. DMF-LAMP is performed with enhanced sensitivity without compromising reaction efficacy or losing reliability and efficiency, by LAMP-amplifying 0.5 ng/µL of target DNA in just 45 min. Moreover, on-chip LAMP was performed in 1.5 µL, a considerably lower volume than standard bench-top reactions. Full article

(This article belongs to the Special Issue Microfluidic Sensors)

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18 pages, 6283 KiB

Open AccessArticle

Potential of Sentinel-1 Radar Data for the Assessment of Soil and Cereal Cover Parameters

by Safa Bousbih^1,2,*, Mehrez Zribi^1,*

, Zohra Lili-Chabaane², Nicolas Baghdadi³

, Mohammad El Hajj³, Qi Gao^1,4,5 and Bernard Mougenot¹

¹ CESBIO (CNRS/UPS/IRD/CNES), 18 Avenue Edouard Belin, 31401 Toulouse CEDEX 9, France

² Université de Carthage/INAT/LR GREEN-TEAM, 43 Avenue Charles Nicolle, Tunis 1082, Tunisia

³ IRSTEA, UMR TETIS, 500 Rue François Breton, 34093 Montpellier CEDEX 5, France

⁴ IsardSAT, Parc Tecnològic Barcelona Activa, Carrer de Marie Curie, 8, 08042 Barcelona, Spain

⁵ Observatori de l’Ebre (OE), Universitat Ramon Llull-CSIC, 08022 Barcelona, Spain

Sensors 2017, 17(11), 2617; https://doi.org/10.3390/s17112617 - 14 Nov 2017

Cited by 139 | Viewed by 7814

Abstract

The main objective of this study is to analyze the potential use of Sentinel-1 (S1) radar data for the estimation of soil characteristics (roughness and water content) and cereal vegetation parameters (leaf area index (LAI), and vegetation height (H)) in agricultural areas. Simultaneously [...] Read more.

The main objective of this study is to analyze the potential use of Sentinel-1 (S1) radar data for the estimation of soil characteristics (roughness and water content) and cereal vegetation parameters (leaf area index (LAI), and vegetation height (H)) in agricultural areas. Simultaneously to several radar acquisitions made between 2015 and 2017, using S1 sensors over the Kairouan Plain (Tunisia, North Africa), ground measurements of soil roughness, soil water content, LAI and H were recorded. The NDVI (normalized difference vegetation index) index computed from Landsat optical images revealed a strong correlation with in situ measurements of LAI. The sensitivity of the S1 measurements to variations in soil moisture, which has been reported in several scientific publications, is confirmed in this study. This sensitivity decreases with increasing vegetation cover growth (NDVI), and is stronger in the VV (vertical) polarization than in the VH cross-polarization. The results also reveal a similar increase in the dynamic range of radar signals observed in the VV and VH polarizations as a function of soil roughness. The sensitivity of S1 measurements to vegetation parameters (LAI and H) in the VV polarization is also determined, showing that the radar signal strength decreases when the vegetation parameters increase. No vegetation parameter sensitivity is observed in the VH polarization, probably as a consequence of volume scattering effects. Full article

(This article belongs to the Special Issue Sensors and Smart Sensing of Agricultural Land Systems)

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16 pages, 5959 KiB

Open AccessArticle

Computational Experiments on the Step and Frequency Responses of a Three-Axis Thermal Accelerometer

by Yoshifumi Ogami^1,*

, Naoya Murakita² and Koji Fukudome¹

¹ Department of Mechanical Engineering, College of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga 525-8577, Japan

² Murata Manufacturing Co., Ltd., Kyoto 617-8555, Japan

Sensors 2017, 17(11), 2618; https://doi.org/10.3390/s17112618 - 14 Nov 2017

Cited by 7 | Viewed by 4033

Abstract

The sensor response has been reported to become highly nonlinear when the acceleration added to a thermal accelerator is very large, so the same response can be observed for two accelerations with different magnitudes and opposite signs. Some papers have reported the frequency [...] Read more.

The sensor response has been reported to become highly nonlinear when the acceleration added to a thermal accelerator is very large, so the same response can be observed for two accelerations with different magnitudes and opposite signs. Some papers have reported the frequency response for the horizontal acceleration to be a first-order system, while others have reported it to be a second-order system. The response for the vertical acceleration has not been studied. In this study, computational experiments were performed to examine the step and frequency responses of a three-axis thermal accelerometer. The results showed that monitoring the temperatures at two positions and making use of cross-axis sensitivity allow a unique acceleration to be determined even when the range of the vertical acceleration is very large (e.g., −10,000–10,000 g). The frequency response was proven to be a second-order system for horizontal acceleration and a third-order system for vertical acceleration. Full article

(This article belongs to the Special Issue Integrated MEMS Sensors for the IoT Era)

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24 pages, 10345 KiB

Open AccessArticle

An Improved Aerial Target Localization Method with a Single Vector Sensor

by Anbang Zhao^1,2, Xuejie Bi^1,2, Juan Hui^1,2,*, Caigao Zeng^1,2 and Lin Ma^1,2

¹ College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China

² Science and Technology Underwater Acoustic Laboratory, Harbin Engineering University, Harbin 150001, China

Sensors 2017, 17(11), 2619; https://doi.org/10.3390/s17112619 - 14 Nov 2017

Cited by 11 | Viewed by 3537

Abstract

This paper focuses on the problems encountered in the actual data processing with the use of the existing aerial target localization methods, analyzes the causes of the problems, and proposes an improved algorithm. Through the processing of the sea experiment data, it is [...] Read more.

This paper focuses on the problems encountered in the actual data processing with the use of the existing aerial target localization methods, analyzes the causes of the problems, and proposes an improved algorithm. Through the processing of the sea experiment data, it is found that the existing algorithms have higher requirements for the accuracy of the angle estimation. The improved algorithm reduces the requirements of the angle estimation accuracy and obtains the robust estimation results. The closest distance matching estimation algorithm and the horizontal distance estimation compensation algorithm are proposed. The smoothing effect of the data after being post-processed by using the forward and backward two-direction double-filtering method has been improved, thus the initial stage data can be filtered, so that the filtering results retain more useful information. In this paper, the aerial target height measurement methods are studied, the estimation results of the aerial target are given, so as to realize the three-dimensional localization of the aerial target and increase the understanding of the underwater platform to the aerial target, so that the underwater platform has better mobility and concealment. Full article

(This article belongs to the Section Physical Sensors)

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16 pages, 1817 KiB

Open AccessArticle

Analytical Parameters of an Amperometric Glucose Biosensor for Fast Analysis in Food Samples

by Margalida Artigues

, Jordi Abellà

and Sergi Colominas^*

Electrochemical Methods Laboratory—Analytical and Applied Chemistry Department, ETS Institut Químic de Sarrià, Universitat Ramon Llull, Via Augusta, 390, 08017 Barcelona, Spain

Sensors 2017, 17(11), 2620; https://doi.org/10.3390/s17112620 - 14 Nov 2017

Cited by 59 | Viewed by 8031

Abstract

Amperometric biosensors based on the use of glucose oxidase (GOx) are able to combine the robustness of electrochemical techniques with the specificity of biological recognition processes. However, very little information can be found in literature about the fundamental analytical parameters of these sensors. [...] Read more.

Amperometric biosensors based on the use of glucose oxidase (GOx) are able to combine the robustness of electrochemical techniques with the specificity of biological recognition processes. However, very little information can be found in literature about the fundamental analytical parameters of these sensors. In this work, the analytical behavior of an amperometric biosensor based on the immobilization of GOx using a hydrogel (Chitosan) onto highly ordered titanium dioxide nanotube arrays (TiO₂NTAs) has been evaluated. The GOx–Chitosan/TiO₂NTAs biosensor showed a sensitivity of 5.46 μA·mM⁻¹ with a linear range from 0.3 to 1.5 mM; its fundamental analytical parameters were studied using a commercial soft drink. The obtained results proved sufficient repeatability (RSD = 1.9%), reproducibility (RSD = 2.5%), accuracy (95–105% recovery), and robustness (RSD = 3.3%). Furthermore, no significant interferences from fructose, ascorbic acid and citric acid were obtained. In addition, the storage stability was further examined, after 30 days, the GOx–Chitosan/TiO₂NTAs biosensor retained 85% of its initial current response. Finally, the glucose content of different food samples was measured using the biosensor and compared with the respective HPLC value. In the worst scenario, a deviation smaller than 10% was obtained among the 20 samples evaluated. Full article

(This article belongs to the Special Issue I3S 2017 Selected Papers)

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10 pages, 1971 KiB

Open AccessArticle

Wearable Wide-Range Strain Sensors Based on Ionic Liquids and Monitoring of Human Activities

by Shao-Hui Zhang^1,2, Feng-Xia Wang^2,*, Jia-Jia Li², Hong-Dan Peng², Jing-Hui Yan^1,* and Ge-Bo Pan^2,*

¹ College of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Changchun 130022, China

² Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China

Sensors 2017, 17(11), 2621; https://doi.org/10.3390/s17112621 - 14 Nov 2017

Cited by 67 | Viewed by 6967

Abstract

Wearable sensors for detection of human activities have encouraged the development of highly elastic sensors. In particular, to capture subtle and large-scale body motion, stretchable and wide-range strain sensors are highly desired, but still a challenge. Herein, a highly stretchable and transparent stain [...] Read more.

Wearable sensors for detection of human activities have encouraged the development of highly elastic sensors. In particular, to capture subtle and large-scale body motion, stretchable and wide-range strain sensors are highly desired, but still a challenge. Herein, a highly stretchable and transparent stain sensor based on ionic liquids and elastic polymer has been developed. The as-obtained sensor exhibits impressive stretchability with wide-range strain (from 0.1% to 400%), good bending properties and high sensitivity, whose gauge factor can reach 7.9. Importantly, the sensors show excellent biological compatibility and succeed in monitoring the diverse human activities ranging from the complex large-scale multidimensional motions to subtle signals, including wrist, finger and elbow joint bending, finger touch, breath, speech, swallow behavior and pulse wave. Full article

(This article belongs to the Section Physical Sensors)

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15 pages, 9096 KiB

Open AccessArticle

Spatial-Temporal Dynamics of Cropping Frequency in Hubei Province over 2001–2015

by Jianbin Tao¹, Wenbin Wu^2,* and Wenbin Liu¹

¹ Key Laboratory for Geographical Process Analysis & Simulation of Hubei Province/College of Urban and Environmental Sciences, Central China Normal University, Wuhan 430079, China

² Key Laboratory of Agricultural Remote Sensing, Ministry of Agriculture/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China

Sensors 2017, 17(11), 2622; https://doi.org/10.3390/s17112622 - 14 Nov 2017

Cited by 11 | Viewed by 4102

Abstract

Mapping crop patterns with remote sensing data is of great importance for agricultural production, food security and agricultural sustainability. In this paper, a hierarchical clustering method was proposed to map cropping frequency from time-series Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Indices (EVI) [...] Read more.

Mapping crop patterns with remote sensing data is of great importance for agricultural production, food security and agricultural sustainability. In this paper, a hierarchical clustering method was proposed to map cropping frequency from time-series Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Indices (EVI) data and the spatial and temporal patterns of cropping frequency from 2001 to 2015 in Hubei Province of China were analyzed. The results are as follows: (1) The total double crop areas decreased slightly, while total single crop areas decreased significantly during 2001 and 2015; (2) The transfer between double crop and single crop was frequent in Hubei with about 11~15% croplands changed their cropping frequency every 5 years; (3) The crop system has obvious regional differentiation for their change trend at the county level. Full article

(This article belongs to the Special Issue Sensors and Smart Sensing of Agricultural Land Systems)

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17 pages, 1787 KiB

Open AccessArticle

Design and Calibration of a Novel Bio-Inspired Pixelated Polarized Light Compass

by Guoliang Han¹

, Xiaoping Hu^1,*, Junxiang Lian¹, Xiaofeng He¹, Lilian Zhang¹, Yujie Wang¹ and Fengliang Dong²

¹ College of Mechatronics and Automation, National University of Defense Technology, Changsha 410073, China

² Nanofabrication Laboratory, Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China

Sensors 2017, 17(11), 2623; https://doi.org/10.3390/s17112623 - 14 Nov 2017

Cited by 53 | Viewed by 7533

Abstract

Animals, such as Savannah sparrows and North American monarch butterflies, are able to obtain compass information from skylight polarization patterns to help them navigate effectively and robustly. Inspired by excellent navigation ability of animals, this paper proposes a novel image-based polarized light compass, [...] Read more.

Animals, such as Savannah sparrows and North American monarch butterflies, are able to obtain compass information from skylight polarization patterns to help them navigate effectively and robustly. Inspired by excellent navigation ability of animals, this paper proposes a novel image-based polarized light compass, which has the advantages of having a small size and being light weight. Firstly, the polarized light compass, which is composed of a Charge Coupled Device (CCD) camera, a pixelated polarizer array and a wide-angle lens, is introduced. Secondly, the measurement method of a skylight polarization pattern and the orientation method based on a single scattering Rayleigh model are presented. Thirdly, the error model of the sensor, mainly including the response error of CCD pixels and the installation error of the pixelated polarizer, is established. A calibration method based on iterative least squares estimation is proposed. In the outdoor environment, the skylight polarization pattern can be measured in real time by our sensor. The orientation accuracy of the sensor increases with the decrease of the solar elevation angle, and the standard deviation of orientation error is

0 . 15^{\circ}

at sunset. Results of outdoor experiments show that the proposed polarization navigation sensor can be used for outdoor autonomous navigation. Full article

(This article belongs to the Special Issue Image Sensors)

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9 pages, 2445 KiB

Open AccessArticle

Acoustic Sensors Based on Amino-Functionalized Nanoparticles to Detect Volatile Organic Solvents

by Daniel Matatagui^1,*, Oleg Kolokoltsev¹, José Manuel Saniger¹, Isabel Gràcia²

, María Jesús Fernández³, Jose Luis Fontecha³ and María del Carmen Horrillo^3,*

¹ Centro de Ciencias Aplicadas y Dessarrollo Tecnológico (CCADET), UNAM, 04510 Ciudad de Mexico, Mexico

² Instituto de Microelectrónica de Barcelona (IMB), CSIC, Campus UAB, 08193 Bellaterra, Spain

³ Instituto de Tecnologías Físicas y de la Información (ITEFI), CSIC, Serrano 144, 28006 Madrid, Spain

Sensors 2017, 17(11), 2624; https://doi.org/10.3390/s17112624 - 14 Nov 2017

Cited by 11 | Viewed by 4273

Abstract

Love-wave gas sensors based on surface functionalized iron oxide nanoparticles has been developed in this research. Amino-terminated iron oxide nanoparticles were deposited, by a spin coating technique, onto the surface of Love-wave sensors, as a very reproducible gas-sensing layer. The gases tested were [...] Read more.

Love-wave gas sensors based on surface functionalized iron oxide nanoparticles has been developed in this research. Amino-terminated iron oxide nanoparticles were deposited, by a spin coating technique, onto the surface of Love-wave sensors, as a very reproducible gas-sensing layer. The gases tested were organic solvents, such as butanol, isopropanol, toluene and xylene, for a wide and low concentration range, obtaining great responses, fast response times of a few minutes (the time at which the device produced a signal change equal to 90%), good reproducibilities, and different responses for each detected solvent. The estimated limits of detection obtained have been very low for each detected compound, about 1 ppm for butanol, 12 ppm for isopropanol, 3 ppm for toluene and 0.5 ppm for xylene. Therefore, it is demonstrated that this type of acoustic wave sensor, with surface amino-functionalized nanoparticles, is a good alternative to those ones functionalized with metal nanoparticles, which result very expensive sensors to achieve worse results. Full article

(This article belongs to the Section Chemical Sensors)

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13 pages, 1736 KiB

Open AccessArticle

Detection of Partial Discharge Sources Using UHF Sensors and Blind Signal Separation

by Carlos Boya¹, Guillermo Robles²

, Emilio Parrado-Hernández³

and Marta Ruiz-Llata^1,*

¹ Department of Electronic Technology, Universidad Carlos III de Madrid, Avda, Universidad, 30, 28911 Leganés, Madrid, Spain

² Department of Electrical Engineering, Universidad Carlos III de Madrid, Avda, Universidad, 30, 28911 Leganés, Madrid, Spain

³ Department of Signal Processing and Communications, Universidad Carlos III de Madrid, Avda, Universidad, 30, 28911 Leganés, Madrid, Spain

Sensors 2017, 17(11), 2625; https://doi.org/10.3390/s17112625 - 15 Nov 2017

Cited by 22 | Viewed by 6426

Abstract

The measurement of the emitted electromagnetic energy in the UHF region of the spectrum allows the detection of partial discharges and, thus, the on-line monitoring of the condition of the insulation of electrical equipment. Unfortunately, determining the affected asset is difficult when there [...] Read more.

The measurement of the emitted electromagnetic energy in the UHF region of the spectrum allows the detection of partial discharges and, thus, the on-line monitoring of the condition of the insulation of electrical equipment. Unfortunately, determining the affected asset is difficult when there are several simultaneous insulation defects. This paper proposes the use of an independent component analysis (ICA) algorithm to separate the signals coming from different partial discharge (PD) sources. The performance of the algorithm has been tested using UHF signals generated by test objects. The results are validated by two automatic classification techniques: support vector machines and similarity with class mean. Both methods corroborate the suitability of the algorithm to separate the signals emitted by each PD source even when they are generated by the same type of insulation defect. Full article

(This article belongs to the Special Issue UHF and RF Sensor Technology for Partial Discharge Detection)

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33 pages, 13255 KiB

Open AccessArticle

Scene-Aware Adaptive Updating for Visual Tracking via Correlation Filters

by Fan Li^*

, Sirou Zhang and Xiaoya Qiao

Department of Information and Communication Engineering, School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an 710049, China

Sensors 2017, 17(11), 2626; https://doi.org/10.3390/s17112626 - 15 Nov 2017

Cited by 14 | Viewed by 6412

Abstract

In recent years, visual object tracking has been widely used in military guidance, human-computer interaction, road traffic, scene monitoring and many other fields. The tracking algorithms based on correlation filters have shown good performance in terms of accuracy and tracking speed. However, their [...] Read more.

In recent years, visual object tracking has been widely used in military guidance, human-computer interaction, road traffic, scene monitoring and many other fields. The tracking algorithms based on correlation filters have shown good performance in terms of accuracy and tracking speed. However, their performance is not satisfactory in scenes with scale variation, deformation, and occlusion. In this paper, we propose a scene-aware adaptive updating mechanism for visual tracking via a kernel correlation filter (KCF). First, a low complexity scale estimation method is presented, in which the corresponding weight in five scales is employed to determine the final target scale. Then, the adaptive updating mechanism is presented based on the scene-classification. We classify the video scenes as four categories by video content analysis. According to the target scene, we exploit the adaptive updating mechanism to update the kernel correlation filter to improve the robustness of the tracker, especially in scenes with scale variation, deformation, and occlusion. We evaluate our tracker on the CVPR2013 benchmark. The experimental results obtained with the proposed algorithm are improved by 33.3%, 15%, 6%, 21.9% and 19.8% compared to those of the KCF tracker on the scene with scale variation, partial or long-time large-area occlusion, deformation, fast motion and out-of-view. Full article

(This article belongs to the Special Issue Video Analysis and Tracking Using State-of-the-Art Sensors)

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22 pages, 13845 KiB

Open AccessArticle

Electrochemical and Infrared Absorption Spectroscopy Detection of SF₆ Decomposition Products

by Ming Dong¹, Chongxing Zhang¹

, Ming Ren^1,*, Ricardo Albarracín²

and Rixin Ye³

¹ State Key Laboratory of Electrical Insulation for Power Equipment, Xi’an Jiaotong University, Xi’an 710049, China

² Departamento de Ingeniería Eléctrica, Electrónica, Automática y Física Aplicada, Escuela Técnica Superior de Ingeniería y Diseño Industrial (ETSIDI), Universidad Politécnica de Madrid (UPM), Ronda de Valencia 3, Madrid 28012, Spain

³ Maintenance Company of State Grid Shaanxi Electric Power Company, Xi’an 710065, China

Sensors 2017, 17(11), 2627; https://doi.org/10.3390/s17112627 - 15 Nov 2017

Cited by 45 | Viewed by 9612

Abstract

Sulfur hexafluoride (SF₆) gas-insulated electrical equipment is widely used in high-voltage (HV) and extra-high-voltage (EHV) power systems. Partial discharge (PD) and local heating can occur in the electrical equipment because of insulation faults, which results in SF₆ decomposition and ultimately [...] Read more.

Sulfur hexafluoride (SF₆) gas-insulated electrical equipment is widely used in high-voltage (HV) and extra-high-voltage (EHV) power systems. Partial discharge (PD) and local heating can occur in the electrical equipment because of insulation faults, which results in SF₆ decomposition and ultimately generates several types of decomposition products. These SF₆ decomposition products can be qualitatively and quantitatively detected with relevant detection methods, and such detection contributes to diagnosing the internal faults and evaluating the security risks of the equipment. At present, multiple detection methods exist for analyzing the SF₆ decomposition products, and electrochemical sensing (ES) and infrared (IR) spectroscopy are well suited for application in online detection. In this study, the combination of ES with IR spectroscopy is used to detect SF₆ gas decomposition. First, the characteristics of these two detection methods are studied, and the data analysis matrix is established. Then, a qualitative and quantitative analysis ES-IR model is established by adopting a two-step approach. A SF₆ decomposition detector is designed and manufactured by combining an electrochemical sensor and IR spectroscopy technology. The detector is used to detect SF₆ gas decomposition and is verified to reliably and accurately detect the gas components and concentrations. Full article

(This article belongs to the Special Issue Spectroscopy Based Sensors)

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11 pages, 3044 KiB

Open AccessArticle

Interaction between Diethyldithiocarbamate and Cu(II) on Gold in Non-Cyanide Wastewater

by Nguyễn Hoàng Ly¹

, Thanh Danh Nguyen^1,2, Kyung-Duk Zoh^3,* and Sang-Woo Joo^1,2,*

¹ Department of Chemistry, Soongsil University, Seoul 156-743, Korea

² Department of Information Communication, Materials, Chemistry Convergence Technology, Soongsil University, Seoul 156-743, Korea

³ Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul 08826, Korea

Sensors 2017, 17(11), 2628; https://doi.org/10.3390/s17112628 - 15 Nov 2017

Cited by 21 | Viewed by 7639

Abstract

A surface-enhanced Raman scattering (SERS) detection method for environmental copper ions (Cu²⁺) was developed according to the vibrational spectral change of diethyldithiocarbamate (DDTC) on gold nanoparticles (AuNPs). The ultraviolet-visible (UV-Vis) absorption spectra indicated that DDTC formed a complex with Cu²⁺ [...] Read more.

A surface-enhanced Raman scattering (SERS) detection method for environmental copper ions (Cu²⁺) was developed according to the vibrational spectral change of diethyldithiocarbamate (DDTC) on gold nanoparticles (AuNPs). The ultraviolet-visible (UV-Vis) absorption spectra indicated that DDTC formed a complex with Cu²⁺, showing a prominent peak at ~450 nm. We found Raman spectral changes in DDTC from ~1490 cm⁻¹ to ~1504 cm⁻¹ on AuNPs at a high concentration of Cu²⁺ above 1 μM. The other ions of Zn²⁺, Pb²⁺, Ni²⁺, NH₄⁺, Mn²⁺, Mg²⁺, K⁺, Hg²⁺, Fe²⁺, Fe³⁺, Cr³⁺, Co²⁺, Cd²⁺, and Ca²⁺ did not produce such spectral changes, even after they reacted with DDTC. The electroplating industrial wastewater samples were tested under the interference of highly concentrated ions of Fe³⁺, Ni²⁺, and Zn²⁺. The Raman spectroscopy-based quantification of Cu²⁺ ions was able to be achieved for the wastewater after treatment with alkaline chlorination, whereas the cyanide-containing water did not show any spectral changes, due to the complexation of the cyanide with the Cu²⁺ ions. A micromolar range detection limit of Cu²⁺ ions could be achieved by analyzing the Raman spectra of DDTC in the cyanide-removed water. Full article

(This article belongs to the Special Issue Surface Plasmon Resonance Sensing)

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15 pages, 5419 KiB

Open AccessArticle

I-DWRL: Improved Dual Wireless Radio Localization Using Magnetometer

by Abdul Aziz¹, Ramesh Kumar² and Inwhee Joe^3,*

¹ Department of Electronics and Computer Engineering, Hanyang University, Seoul 04763, Korea

² Department of Electronic Engineering, Dawood University of Engineering and Technology, Karachi 74800, Pakistan

³ Division of Computer Science and Engineering, Hanyang University, Seoul 04763, Korea

Sensors 2017, 17(11), 2630; https://doi.org/10.3390/s17112630 - 15 Nov 2017

Cited by 1 | Viewed by 3950

Abstract

In the dual wireless radio localization (DWRL) technique each sensor node is equipped with two ultra-wide band (UWB) radios; the distance between the two radios is a few tens of centimeters. For localization, the DWRL technique must use at least two pre-localized nodes [...] Read more.

In the dual wireless radio localization (DWRL) technique each sensor node is equipped with two ultra-wide band (UWB) radios; the distance between the two radios is a few tens of centimeters. For localization, the DWRL technique must use at least two pre-localized nodes to fully localize an unlocalized node. Moreover, in the DWRL technique it is also not possible for two sensor nodes to properly communicate location information unless each of the four UWB radios of two communicating sensor nodes cannot approach the remaining three radios. In this paper, we propose an improved DWRL (I-DWRL) algorithm along with mounting a magnetometer sensor on one of the UWB radios of all sensor nodes. This addition of a magnetometer helps to improve DWRL algorithm such that only one localized sensor node is required for the localization of an unlocalized sensor node, and localization can also be achieved even when some of the four radios of two nodes are unable to communicate with the remaining three radios. The results show that with the use of a magnetometer a greater number of nodes can be localized with a smaller transmission range, less energy and a shorter period of time. In comparison with the conventional DWRL algorithm, our I-DWRL not only maintains the localization error but also requires around half of semi-localizations, 60% of the time, 70% of the energy and a shorter communication range to fully localize an entire network. Moreover, I-DWRL can even localize more nodes while transmission range is not sufficient for DWRL algorithm. Full article

(This article belongs to the Special Issue Sensors and Sensing in Indoor Localization, Tracking, Navigation and Activity Monitoring)

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19 pages, 3317 KiB

Open AccessArticle

A New Low Complexity Angle of Arrival Algorithm for 1D and 2D Direction Estimation in MIMO Smart Antenna Systems

by Mohammed A. G. Al-Sadoon^1,2, Nazar T. Ali^1,3

, Yousf Dama^1,4

, Abdulkareim Zuid^1,2, Stephen M. R. Jones¹, Raed A. Abd-Alhameed^1,*

and James M. Noras¹

¹ School of Engineering and Informatics, University of Bradford, Bradford BD7 1DP, UK

² Department of Communication and Informatics Engineering, Basra University College of Science and Technology, Basra 61004, Iraq

³ Department of Electrical and Computer Engineering, Khalifa University, Abu Dhabi 127788, UAE

⁴ Department of Electrical Engineering, Najah National University, Omar Ibn Al-Khattab St., 44859 Nablus, Palestine

Sensors 2017, 17(11), 2631; https://doi.org/10.3390/s17112631 - 15 Nov 2017

Cited by 34 | Viewed by 7581

Abstract

This paper proposes a new low complexity angle of arrival (AOA) method for signal direction estimation in multi-element smart wireless communication systems. The new method estimates the AOAs of the received signals directly from the received signals with significantly reduced complexity since it [...] Read more.

This paper proposes a new low complexity angle of arrival (AOA) method for signal direction estimation in multi-element smart wireless communication systems. The new method estimates the AOAs of the received signals directly from the received signals with significantly reduced complexity since it does not need to construct the correlation matrix, invert the matrix or apply eigen-decomposition, which are computationally expensive. A mathematical model of the proposed method is illustrated and then verified using extensive computer simulations. Both linear and circular sensors arrays are studied using various numerical examples. The method is systematically compared with other common and recently introduced AOA methods over a wide range of scenarios. The simulated results show that the new method has several advantages in terms of reduced complexity and improved accuracy under the assumptions of correlated signals and limited numbers of snapshots. Full article

(This article belongs to the Special Issue Recent Advances in Array Signal Processing and Its Applications in IoT Security)

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18 pages, 22821 KiB

Open AccessArticle

Crack Propagation Calculations for Optical Fibers under Static Bending and Tensile Loads Using Continuum Damage Mechanics

by Yunxia Chen^1,2, Yuxuan Cui^1,2 and Wenjun Gong^1,2,*

¹ School of Reliability and System Engineering, Beihang University, Weimin Building, No. 37, Xueyuan Road, Haidian District, Beijing 100191, China

² Science and Technology on Reliability and Environmental Engineering Laboratory, Beijing 100191, China

Sensors 2017, 17(11), 2633; https://doi.org/10.3390/s17112633 - 15 Nov 2017

Cited by 4 | Viewed by 5679

Abstract

Static fatigue behavior is the main failure mode of optical fibers applied in sensors. In this paper, a computational framework based on continuum damage mechanics (CDM) is presented to calculate the crack propagation process and failure time of optical fibers subjected to static [...] Read more.

Static fatigue behavior is the main failure mode of optical fibers applied in sensors. In this paper, a computational framework based on continuum damage mechanics (CDM) is presented to calculate the crack propagation process and failure time of optical fibers subjected to static bending and tensile loads. For this purpose, the static fatigue crack propagation in the glass core of the optical fiber is studied. Combining a finite element method (FEM), we use the continuum damage mechanics for the glass core to calculate the crack propagation path and corresponding failure time. In addition, three factors including bending radius, tensile force and optical fiber diameter are investigated to find their impacts on the crack propagation process and failure time of the optical fiber under concerned situations. Finally, experiments are conducted and the results verify the correctness of the simulation calculation. It is believed that the proposed method could give a straightforward description of the crack propagation path in the inner glass core. Additionally, the predicted crack propagation time of the optical fiber with different factors can provide effective suggestions for improving the long-term usage of optical fibers. Full article

(This article belongs to the Special Issue Optical Sensors based on Micro/Nanofibres)

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12 pages, 2416 KiB

Open AccessArticle

A Human Body Pressure Distribution Imaging System Based on Wavelet Analysis and Resistance Tomography

by Shuanfeng Zhao^*

, Wenbo Wang

, Wei Guo and Chuanwei Zhang

School of Mechanical Engineering, Xi’an University of Science and Technology, Xi’an 710054, China

Sensors 2017, 17(11), 2634; https://doi.org/10.3390/s17112634 - 15 Nov 2017

Cited by 9 | Viewed by 3953

Abstract

In this paper, a pressure distribution sensing system based on wavelet analysis and resistance tomography is proposed to overcome the shortcomings of a traditional electrode type pressure distribution sensor, which needs to be arranged with many electrodes and has a high production cost. [...] Read more.

In this paper, a pressure distribution sensing system based on wavelet analysis and resistance tomography is proposed to overcome the shortcomings of a traditional electrode type pressure distribution sensor, which needs to be arranged with many electrodes and has a high production cost. The system uses ADS1256, a constant current source module, a serial communication module, a Raspberry host, a touch screen, and other components. The wavelet transform is used to preprocess the collected signal to improve the anti-jamming performance of the system. The method of resistance tomography is used to realize the real-time imaging of pressure distribution. Finally, the reliability of the system is verified using conductive silica gel as a sensitive material. The experimental results show that wavelet analysis preprocessing can significantly improve the quality of pressure distribution imaging. Full article

(This article belongs to the Special Issue Biosensing for Interfacial Science)

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9 pages, 3899 KiB

Open AccessArticle

A Passive and Wireless Sensor for Bone Plate Strain Monitoring

by Yisong Tan

, Jiale Hu, Limin Ren^*

, Jianhua Zhu, Jiaqi Yang and Di Liu

School of Mechanical Engineering, Northeast Electric Power University, Jilin 132012, China

Sensors 2017, 17(11), 2635; https://doi.org/10.3390/s17112635 - 16 Nov 2017

Cited by 25 | Viewed by 6559

Abstract

This paper reports on a sensor for monitoring bone plate strain in real time. The detected bone plate strain could be used for judging the healing state of fractures in patients. The sensor consists of a magnetoelastic material, which can be wirelessly connected [...] Read more.

This paper reports on a sensor for monitoring bone plate strain in real time. The detected bone plate strain could be used for judging the healing state of fractures in patients. The sensor consists of a magnetoelastic material, which can be wirelessly connected and passively embedded. In order to verify the effectiveness of the sensor, a tibia-bone plate-screw (TBS) model was established using the finite element analysis method. A variation of the bone plate strain was obtained via this model. A goat hindquarter tibia was selected as the bone fracture model in the experiment. The tibia was fixed on a high precision load platform and an external force was applied. Bone plate strain variation during the bone fracture healing process was acquired with sensing coils. Simulation results indicated that bone plate strain decreases as the bone gradually heals, which is consistent with the finite element analysis results. This validated the soundness of the sensor reported here. This sensor has wireless connections, no in vivo battery requirement, and long-term embedding. These results can be used not only for clinical practices of bone fracture healing, but also for bone fracture treatment and rehabilitation equipment design. Full article

(This article belongs to the Section Physical Sensors)

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11 pages, 2626 KiB

Open AccessArticle

Mediator Preference of Two Different FAD-Dependent Glucose Dehydrogenases Employed in Disposable Enzyme Glucose Sensors

by Noya Loew^1,2, Wakako Tsugawa^1,2, Daichi Nagae¹, Katsuhiro Kojima³ and Koji Sode^1,2,3,*

¹ Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan

² Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, 3-8-1 Harumi-cho, Fuchu, Tokyo 183-8538, Japan

³ Ultizyme International Ltd., 1-13-16, Minami, Meguro, Tokyo 152-0013, Japan

Sensors 2017, 17(11), 2636; https://doi.org/10.3390/s17112636 - 16 Nov 2017

Cited by 40 | Viewed by 8024

Abstract

Most commercially available electrochemical enzyme sensor strips for the measurement of blood glucose use an artificial electron mediator to transfer electrons from the active side of the enzyme to the electrode. One mediator recently gaining attention for commercial sensor strips is hexaammineruthenium(III) chloride. [...] Read more.

Most commercially available electrochemical enzyme sensor strips for the measurement of blood glucose use an artificial electron mediator to transfer electrons from the active side of the enzyme to the electrode. One mediator recently gaining attention for commercial sensor strips is hexaammineruthenium(III) chloride. In this study, we investigate and compare the preference of enzyme electrodes with two different FAD-dependent glucose dehydrogenases (FADGDHs) for the mediators hexaammineruthenium(III) chloride, potassium ferricyanide (the most common mediator in commercial sensor strips), and methoxy phenazine methosulfate (mPMS). One FADGDH is a monomeric fungal enzyme, and the other a hetero-trimeric bacterial enzyme. With the latter, which contains a heme-subunit facilitating the electron transfer, similar response currents are obtained with hexaammineruthenium(III), ferricyanide, and mPMS (6.8 µA, 7.5 µA, and 6.4 µA, respectively, for 10 mM glucose). With the fungal FADGDH, similar response currents are obtained with the negatively charged ferricyanide and the uncharged mPMS (5.9 µA and 6.7 µA, respectively, for 10 mM glucose), however, no response current is obtained with hexaammineruthenium(III), which has a strong positive charge. These results show that access of even very small mediators with strong charges to a buried active center can be almost completely blocked by the protein. Full article

(This article belongs to the Special Issue Dedication to Professor Eiichi Tamiya: Over 30 Years of Outstanding Contributions to the Field of Sensors and Biosensors)

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18 pages, 9334 KiB

Open AccessArticle

Design and Clinical Evaluation of a Non-Contact Heart Rate Variability Measuring Device

by Jure Kranjec¹, Samo Beguš¹, Gregor Geršak¹

, Matjaž Šinkovec², Janko Drnovšek¹ and Domen Hudoklin^1,*

¹ Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, 1000 Ljubljana, Slovenia

² Clinical Department of Cardiology, University Medical Centre Ljubljana, Zaloška 7, 1000 Ljubljana, Slovenia

Sensors 2017, 17(11), 2637; https://doi.org/10.3390/s17112637 - 16 Nov 2017

Cited by 17 | Viewed by 5865

Abstract

The object of the proposed paper is to design and analyze the performance of a non-contact heart rate variability (HRV) measuring device based on ultrasound transducers. The rationale behind non-contact HRV measurement is the goal of obtaining a means of long [...] Read more.

The object of the proposed paper is to design and analyze the performance of a non-contact heart rate variability (HRV) measuring device based on ultrasound transducers. The rationale behind non-contact HRV measurement is the goal of obtaining a means of long term monitoring of a patient’s heart performance. Due to its complexity as a non-contact measuring device, influential physical quantities, error source and other perturbations were thoroughly investigated. For medical purposes it is of utmost importance to define the target uncertainty of a measuring method from the side of physicians, while it is the role of scientists to realistically evaluate all uncertainty contributions. Within this paper we present a novelty method of non-contact HRV measurement based on ultrasound transducers operating at two frequencies simultaneously. We report laboratory results and clinical evaluations are given for healthy subjects as well as patients with known heart conditions. Furthermore, laboratory tests were conducted on subjects during a relaxation period, and after 1 min physical activity Full article

(This article belongs to the Special Issue Sensors for Health Monitoring and Disease Diagnosis)

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9 pages, 4070 KiB

Open AccessArticle

Estimating Crop Area at County Level on the North China Plain with an Indirect Sampling of Segments and an Adapted Regression Estimator

by Qinghan Dong^1,*, Jia Liu², Limin Wang², Zhongxin Chen² and Javier Gallego³

¹ Department of Remote Sensing, Flemish Institute of Technological Research, 2400 Mol, Belgium

² Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China

³ Joint Research Centre, The European Commission, 21027 Ispra, Italy

Sensors 2017, 17(11), 2638; https://doi.org/10.3390/s17112638 - 16 Nov 2017

Cited by 4 | Viewed by 4105

Abstract

Image classifications, including sub-pixel analysis, are often used to estimate crop acreage directly. However, this type of assessment often leads to a biased estimation, because commission and omission errors generally do not compensate for each other. Regression estimators combine remote sensing information with [...] Read more.

Image classifications, including sub-pixel analysis, are often used to estimate crop acreage directly. However, this type of assessment often leads to a biased estimation, because commission and omission errors generally do not compensate for each other. Regression estimators combine remote sensing information with more accurate ground data on a field sample, and can result in more accurate and cost-effective assessments of crop acreage. In this pilot study, which aims to produce crop statistics in Guoyang County, the area frame sampling approach is adapted to a strip-like cropping pattern on the North China Plain. Remote sensing information is also used to perform a stratification in which non-agricultural areas are excluded from the ground survey. In order to compute crop statistics, 202 ground points in the agriculture stratum were surveyed. Image classification was included as an auxiliary variable in the subsequent analysis to obtain a regression estimator. The results of this pilot study showed that the integration of remote sensing information as an auxiliary variable can improve the accuracy of estimation by reducing the variance of the estimates, as well as the cost effectiveness of an operational application at the county level in the region. Full article

(This article belongs to the Special Issue Sensors in Agriculture)

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23 pages, 5639 KiB

Open AccessArticle

Benthic Habitat Mapping Using Multispectral High-Resolution Imagery: Evaluation of Shallow Water Atmospheric Correction Techniques

by Francisco Eugenio^*, Javier Marcello

, Javier Martin and Dionisio Rodríguez-Esparragón

Instituto Oceanografía y Cambio Global (IOCAG), Universidad de Las Palmas de Gran Canaria (ULPGC), Campus Universitario de Tafira, 35017 Las Palmas de G.C., Spain

Sensors 2017, 17(11), 2639; https://doi.org/10.3390/s17112639 - 16 Nov 2017

Cited by 53 | Viewed by 6512

Abstract

Remote multispectral data can provide valuable information for monitoring coastal water ecosystems. Specifically, high-resolution satellite-based imaging systems, as WorldView-2 (WV-2), can generate information at spatial scales needed to implement conservation actions for protected littoral zones. However, coastal water-leaving radiance arriving at the space-based [...] Read more.

Remote multispectral data can provide valuable information for monitoring coastal water ecosystems. Specifically, high-resolution satellite-based imaging systems, as WorldView-2 (WV-2), can generate information at spatial scales needed to implement conservation actions for protected littoral zones. However, coastal water-leaving radiance arriving at the space-based sensor is often small as compared to reflected radiance. In this work, complex approaches, which usually use an accurate radiative transfer code to correct the atmospheric effects, such as FLAASH, ATCOR and 6S, have been implemented for high-resolution imagery. They have been assessed in real scenarios using field spectroradiometer data. In this context, the three approaches have achieved excellent results and a slightly superior performance of 6S model-based algorithm has been observed. Finally, for the mapping of benthic habitats in shallow-waters marine protected environments, a relevant application of the proposed atmospheric correction combined with an automatic deglinting procedure is presented. This approach is based on the integration of a linear mixing model of benthic classes within the radiative transfer model of the water. The complete methodology has been applied to selected ecosystems in the Canary Islands (Spain) but the obtained results allow the robust mapping of the spatial distribution and density of seagrass in coastal waters and the analysis of multitemporal variations related to the human activity and climate change in littoral zones. Full article

(This article belongs to the Section Remote Sensors)

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12 pages, 1966 KiB

Open AccessArticle

Effects of Infrared Optical Trapping on Saccharomyces cerevisiae in a Microfluidic System

by Zdeněk Pilát^1,*, Alexandr Jonáš²

, Jan Ježek¹ and Pavel Zemánek¹

¹ Institute of Scientific Instruments of the CAS, v.v.i., Czech Academy of Sciences, Královopolská 147, 612 64 Brno, Czech Republic

² Department of Physics, Istanbul Technical University, Maslak, 34469 Istanbul, Turkey

Sensors 2017, 17(11), 2640; https://doi.org/10.3390/s17112640 - 16 Nov 2017

Cited by 31 | Viewed by 5502

Abstract

Baker’s yeast (Saccharomyces cerevisiae) represents a very popular single-celled eukaryotic model organism which has been studied extensively by various methods and whose genome has been completely sequenced. It was also among the first living organisms that were manipulated by optical tweezers [...] Read more.

Baker’s yeast (Saccharomyces cerevisiae) represents a very popular single-celled eukaryotic model organism which has been studied extensively by various methods and whose genome has been completely sequenced. It was also among the first living organisms that were manipulated by optical tweezers and it is currently a frequent subject of optical micromanipulation experiments. We built a microfluidic system for optical trapping experiments with individual cells and used it for the assessment of cell tolerance to phototoxic stress. Using optical tweezers with the wavelength of 1064 nm, we trapped individual Saccharomyces cerevisiae cells for 15 min and, subsequently, observed their stress response in specially designed microfluidic chambers over time periods of several hours by time-lapse video-microscopy. We determined the time between successive bud formations after the exposure to the trapping light, took account of damaged cells, and calculated the population doubling period and cell areas for increasing trapping power at a constant trapping time. Our approach represents an attractive, versatile microfluidic platform for quantitative optical trapping experiments with living cells. We demonstrate its application potential by assessing the limits for safe, non-invasive optical trapping of Saccharomyces cerevisiae with infrared laser light. Full article

(This article belongs to the Section Biosensors)

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14 pages, 2772 KiB

Open AccessArticle

Real-Time Indoor Scene Description for the Visually Impaired Using Autoencoder Fusion Strategies with Visible Cameras

by Salim Malek¹, Farid Melgani^1,*

, Mohamed Lamine Mekhalfi¹ and Yakoub Bazi²

¹ Department of Information Engineering and Computer Science, University of Trento, Via Sommarive 9, I-38123 Trento, Italy

² College of Computer and Information Sciences, King Saud University, Riyadh 11543, Saudi Arabia

Sensors 2017, 17(11), 2641; https://doi.org/10.3390/s17112641 - 16 Nov 2017

Cited by 14 | Viewed by 4571

Abstract

This paper describes three coarse image description strategies, which are meant to promote a rough perception of surrounding objects for visually impaired individuals, with application to indoor spaces. The described algorithms operate on images (grabbed by the user, by means of a chest-mounted [...] Read more.

This paper describes three coarse image description strategies, which are meant to promote a rough perception of surrounding objects for visually impaired individuals, with application to indoor spaces. The described algorithms operate on images (grabbed by the user, by means of a chest-mounted camera), and provide in output a list of objects that likely exist in his context across the indoor scene. In this regard, first, different colour, texture, and shape-based feature extractors are generated, followed by a feature learning step by means of AutoEncoder (AE) models. Second, the produced features are fused and fed into a multilabel classifier in order to list the potential objects. The conducted experiments point out that fusing a set of AE-learned features scores higher classification rates with respect to using the features individually. Furthermore, with respect to reference works, our method: (i) yields higher classification accuracies, and (ii) runs (at least four times) faster, which enables a potential full real-time application. Full article

(This article belongs to the Special Issue Indoor LiDAR/Vision Systems)

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15 pages, 839 KiB

Open AccessArticle

Fast, Low-Cost and Non-Destructive Physico-Chemical Analysis of Virgin Olive Oils Using Near-Infrared Reflectance Spectroscopy

by Ana Garrido-Varo^1,*, María-Teresa Sánchez^2,*, María-José De la Haba², Irina Torres² and Dolores Pérez-Marín¹

¹ Department of Animal Production, Faculty of Agricultural and Forestry Engineering, University of Cordoba, Campus Rabanales, E-14071 Cordoba, Spain

² Department of Bromatology and Food Technology, Faculty of Agricultural and Forestry Engineering, University of Cordoba, Campus Rabanales, E-14071 Cordoba, Spain

Sensors 2017, 17(11), 2642; https://doi.org/10.3390/s17112642 - 16 Nov 2017

Cited by 36 | Viewed by 6800

Abstract

Near-Infrared (NIR) Spectroscopy was used for the non-destructive assessment of physico-chemical quality parameters in olive oil. At the same time, the influence of the sample presentation mode (spinning versus static cup) was evaluated using two spectrophotometers with similar optical characteristics. A total of [...] Read more.

Near-Infrared (NIR) Spectroscopy was used for the non-destructive assessment of physico-chemical quality parameters in olive oil. At the same time, the influence of the sample presentation mode (spinning versus static cup) was evaluated using two spectrophotometers with similar optical characteristics. A total of 478 olive oil samples were used to develop calibration models, testing various spectral signal pre-treatments. The models obtained by applying MPLS regression to spectroscopic data yielded promising results for olive oil quality measurements, particularly for acidity, the peroxide index and alkyl and ethyl ester content. The results obtained indicate that this non-invasive technology can be used successfully by the olive oil sector to categorize olive oils, to detect potential fraud and to provide consumers with more reliable information. Although both sample presentation modes yielded comparable results, equations constructed with samples scanned using the spinning mode provided greater predictive capacity. Full article

(This article belongs to the Special Issue Spectroscopy Based Sensors)

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7 pages, 2776 KiB

Open AccessArticle

How Well Can We Extract the Permanent Displacement from Low-Cost MEMS Accelerometers?

by Jyh Cherng Jan^1,2

, Wei-An Chao^3,*, Yih-Min Wu^2,4

, Chien-Chih Chen¹ and Cheng-Horng Lin²

¹ Department of Earth Sciences, National Central University, Jhongli 320, Taiwan

² Institute of Earth Sciences, Academia Sinica, Taipei 11529, Taiwan

³ Department of Civil Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan

⁴ Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan

Sensors 2017, 17(11), 2643; https://doi.org/10.3390/s17112643 - 16 Nov 2017

Cited by 12 | Viewed by 4587

Abstract

Following the recent establishment of a high-density seismic network equipped with low-cost micro-electro-mechanical system (MEMS) P-wave-alert-device (P-Alert) by the earthquake early warning (EEW) research group at the National Taiwan University, a large quantity of strong-motion records from moderate-magnitude earthquakes (M [...] Read more.

Following the recent establishment of a high-density seismic network equipped with low-cost micro-electro-mechanical system (MEMS) P-wave-alert-device (P-Alert) by the earthquake early warning (EEW) research group at the National Taiwan University, a large quantity of strong-motion records from moderate-magnitude earthquakes (M_L > 6) around Taiwan has been accumulated. Using a data preprocessing scheme to recover the dynamic average embedded within the P-Alert data, we adopted an automatic baseline correction approach for the P-Alert accelerograms to determine the coseismic deformation (Cd). Comparisons between the Cd values determined using global positioning system (GPS) data, strong-motion records from the P-Alert network, and data from the Taiwan Strong Motion Instrumentation Program (TSMIP) demonstrates that the near-real-time determination of Cd values (>2 cm), which provide crucial information for seismic hazard mitigation, is possible using records from low-cost MEMS accelerometers. Full article

(This article belongs to the Special Issue Earth Observation and In-Situ Sensing for Risk Assessment from Natural Threats)

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23 pages, 10359 KiB

Open AccessArticle

Hyperspectral Image Enhancement and Mixture Deep-Learning Classification of Corneal Epithelium Injuries

by Siti Salwa Md Noor¹, Jinchang Ren¹, Stephen Marshall^1,* and Kaleena Michael²

¹ Centre of Excellent Signal and Image Processing, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow G1 1XW, UK

² Glasgow Centre for Ophthalmic Research, Gartnavel General Hospital, Glasgow G12 0YN, UK

Sensors 2017, 17(11), 2644; https://doi.org/10.3390/s17112644 - 16 Nov 2017

Cited by 60 | Viewed by 6670

Abstract

In our preliminary study, the reflectance signatures obtained from hyperspectral imaging (HSI) of normal and abnormal corneal epithelium tissues of porcine show similar morphology with subtle differences. Here we present image enhancement algorithms that can be used to improve the interpretability of data [...] Read more.

In our preliminary study, the reflectance signatures obtained from hyperspectral imaging (HSI) of normal and abnormal corneal epithelium tissues of porcine show similar morphology with subtle differences. Here we present image enhancement algorithms that can be used to improve the interpretability of data into clinically relevant information to facilitate diagnostics. A total of 25 corneal epithelium images without the application of eye staining were used. Three image feature extraction approaches were applied for image classification: (i) image feature classification from histogram using a support vector machine with a Gaussian radial basis function (SVM-GRBF); (ii) physical image feature classification using deep-learning Convolutional Neural Networks (CNNs) only; and (iii) the combined classification of CNNs and SVM-Linear. The performance results indicate that our chosen image features from the histogram and length-scale parameter were able to classify with up to 100% accuracy; particularly, at CNNs and CNNs-SVM, by employing 80% of the data sample for training and 20% for testing. Thus, in the assessment of corneal epithelium injuries, HSI has high potential as a method that could surpass current technologies regarding speed, objectivity, and reliability. Full article

(This article belongs to the Section Remote Sensors)

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16 pages, 3230 KiB

Open AccessArticle

Visual Positioning Indoors: Human Eyes vs. Smartphone Cameras

by Dewen Wu¹, Ruizhi Chen^1,2,*

and Liang Chen^1,2

¹ State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China

² Collaborative Innovation Center of Geospatial Technology (INNOGST), Wuhan 430079, China

Sensors 2017, 17(11), 2645; https://doi.org/10.3390/s17112645 - 16 Nov 2017

Cited by 13 | Viewed by 5521

Abstract

Artificial Intelligence (AI) technologies and their related applications are now developing at a rapid pace. Indoor positioning will be one of the core technologies that enable AI applications because people spend 80% of their time indoors. Humans can locate themselves related to a [...] Read more.

Artificial Intelligence (AI) technologies and their related applications are now developing at a rapid pace. Indoor positioning will be one of the core technologies that enable AI applications because people spend 80% of their time indoors. Humans can locate themselves related to a visually well-defined object, e.g., a door, based on their visual observations. Can a smartphone camera do a similar job when it points to an object? In this paper, a visual positioning solution was developed based on a single image captured from a smartphone camera pointing to a well-defined object. The smartphone camera simulates the process of human eyes for the purpose of relatively locating themselves against a well-defined object. Extensive experiments were conducted with five types of smartphones on three different indoor settings, including a meeting room, a library, and a reading room. Experimental results shown that the average positioning accuracy of the solution based on five smartphone cameras is 30.6 cm, while that for the human-observed solution with 300 samples from 10 different people is 73.1 cm. Full article

(This article belongs to the Special Issue Sensors and Sensing in Indoor Localization, Tracking, Navigation and Activity Monitoring)

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28 pages, 1176 KiB

Open AccessArticle

A CoAP-Based Network Access Authentication Service for Low-Power Wide Area Networks: LO-CoAP-EAP

by Dan Garcia-Carrillo^1,*

, Rafael Marin-Lopez¹, Arunprabhu Kandasamy^2,3 and Alexander Pelov²

¹ Department Information and Communication Engineering (DIIC), Faculty of Computer Science, University of Murcia, 30100 Murcia, Spain

² Acklio, 2 BIS rue de la Chataigneraie, 35576 Cesson-Sevigne, France

³ Institut MINES TELECOM, TELECOM Bretagne, 2 rue de la Chataigneraie CS 17607, 35576 Cesson-Sevigne CEDEX, France

Sensors 2017, 17(11), 2646; https://doi.org/10.3390/s17112646 - 17 Nov 2017

Cited by 28 | Viewed by 8216

Abstract

The Internet-of-Things (IoT) landscape is expanding with new radio technologies. In addition to the Low-Rate Wireless Personal Area Network (LR-WPAN), the recent set of technologies conforming the so-called Low-Power Wide Area Networks (LP-WAN) offers long-range communications, allowing one to send small pieces of [...] Read more.

The Internet-of-Things (IoT) landscape is expanding with new radio technologies. In addition to the Low-Rate Wireless Personal Area Network (LR-WPAN), the recent set of technologies conforming the so-called Low-Power Wide Area Networks (LP-WAN) offers long-range communications, allowing one to send small pieces of information at a reduced energy cost, which promotes the creation of new IoT applications and services. However, LP-WAN technologies pose new challenges since they have strong limitations in the available bandwidth. In general, a first step prior to a smart object being able to gain access to the network is the process of network access authentication. It involves authentication, authorization and key management operations. This process is of vital importance for operators to control network resources. However, proposals for managing network access authentication in LP-WAN are tailored to the specifics of each technology, which could introduce interoperability problems in the future. In this sense, little effort has been put so far into providing a wireless-independent solution for network access authentication in the area of LP-WAN. To fill this gap, we propose a service named Low-Overhead CoAP-EAP (LO-CoAP-EAP), which is based on previous work designed for LR-WPAN. LO-CoAP-EAP integrates the use of Authentication, Authorization and Accounting (AAA) infrastructures and the Extensible Authentication Protocol (EAP) protocol. For this integration, we use the Constrained Application Protocol (CoAP) to design a network authentication service independent of the type of LP-WAN technology. LO-CoAP-EAP represents a trade-off between flexibility, wireless technology independence, scalability and performance in LP-WAN. Full article

(This article belongs to the Special Issue Security, Trust and Privacy for Sensor Networks)

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14 pages, 2754 KiB

Open AccessArticle

Estimating Stair Running Performance Using Inertial Sensors

by Lauro V. Ojeda^1,*

, Antonia M. Zaferiou², Stephen M. Cain¹

, Rachel V. Vitali¹, Steven P. Davidson¹, Leia A. Stirling³

and Noel C. Perkins¹

¹ Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA

² Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL 60612, USA

³ Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Boston, MA 02139, USA

Sensors 2017, 17(11), 2647; https://doi.org/10.3390/s17112647 - 17 Nov 2017

Cited by 24 | Viewed by 6358

Abstract

Stair running, both ascending and descending, is a challenging aerobic exercise that many athletes, recreational runners, and soldiers perform during training. Studying biomechanics of stair running over multiple steps has been limited by the practical challenges presented while using optical-based motion tracking systems. [...] Read more.

Stair running, both ascending and descending, is a challenging aerobic exercise that many athletes, recreational runners, and soldiers perform during training. Studying biomechanics of stair running over multiple steps has been limited by the practical challenges presented while using optical-based motion tracking systems. We propose using foot-mounted inertial measurement units (IMUs) as a solution as they enable unrestricted motion capture in any environment and without need for external references. In particular, this paper presents methods for estimating foot velocity and trajectory during stair running using foot-mounted IMUs. Computational methods leverage the stationary periods occurring during the stance phase and known stair geometry to estimate foot orientation and trajectory, ultimately used to calculate stride metrics. These calculations, applied to human participant stair running data, reveal performance trends through timing, trajectory, energy, and force stride metrics. We present the results of our analysis of experimental data collected on eleven subjects. Overall, we determine that for either ascending or descending, the stance time is the strongest predictor of speed as shown by its high correlation with stride time. Full article

(This article belongs to the Special Issue Wearable and Ambient Sensors for Healthcare and Wellness Applications)

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12 pages, 3793 KiB

Open AccessArticle

Combining a Disturbance Observer with Triple-Loop Control Based on MEMS Accelerometers for Line-of-Sight Stabilization

by Yong Luo^1,2,3

, Yongmei Huang^1,2, Chao Deng^1,2,3, Yao Mao^1,2,*

, Wei Ren^1,2,3 and Qiongyan Wu^1,2

¹ Key Laboratory of Optical Engineering, Chinese Academy of Sciences, Chengdu 610209, China

² Institute of Optics and Electronics, Chinese Academy of Science, Chengdu 610209, China

³ University of Chinese Academy of Sciences, Beijing 100039, China

Sensors 2017, 17(11), 2648; https://doi.org/10.3390/s17112648 - 17 Nov 2017

Cited by 11 | Viewed by 5929

Abstract

In the CCD-based fine tracking optical system (FTOS), the whole disturbance suppression ability (DSA) is the product of the inner loop and outer position loop. Traditionally, high sampling fiber-optic gyroscopes (FOGs) are added to the platform to stabilize the line-of-sight (LOS). However, because [...] Read more.

In the CCD-based fine tracking optical system (FTOS), the whole disturbance suppression ability (DSA) is the product of the inner loop and outer position loop. Traditionally, high sampling fiber-optic gyroscopes (FOGs) are added to the platform to stabilize the line-of-sight (LOS). However, because of the FOGs’ high cost and relatively big volume relative to the back narrow space of small rotating mirrors, we attempt in this work to utilize a cheaper and smaller micro-electro-mechanical system (MEMS) accelerometer to build the inner loop, replacing the FOG. Unfortunately, since accelerometers are susceptible to the low-frequency noise, according to the classical way of using accelerometers, the crucial low-frequency DSA of the system is insufficient. To solve this problem, in this paper, we propose an approach based on MEMS accelerometers combining disturbance observer (DOB) with triple-loop control (TLC) in which the composite velocity loop is built by acceleration integration and corrected by CCD. The DOB is firstly used to reform the platform, greatly improving the medium-frequency DSA. Then the composite velocity loop exchanges a part of medium-frequency performance for the low-frequency DSA. A detailed analysis and experiments verify the proposed method has a better DSA than the traditional way and could totally substitute FOG in the LOS stabilization. Full article

(This article belongs to the Special Issue Inertial Sensors for Positioning and Navigation)

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15 pages, 4585 KiB

Open AccessArticle

WearETE: A Scalable Wearable E-Textile Triboelectric Energy Harvesting System for Human Motion Scavenging

by Xian Li and Ye Sun^*

Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA

Sensors 2017, 17(11), 2649; https://doi.org/10.3390/s17112649 - 17 Nov 2017

Cited by 20 | Viewed by 5953

Abstract

In this paper, we report the design, experimental validation and application of a scalable, wearable e-textile triboelectric energy harvesting (WearETE) system for scavenging energy from activities of daily living. The WearETE system features ultra-low-cost material and manufacturing methods, high accessibility, and high feasibility [...] Read more.

In this paper, we report the design, experimental validation and application of a scalable, wearable e-textile triboelectric energy harvesting (WearETE) system for scavenging energy from activities of daily living. The WearETE system features ultra-low-cost material and manufacturing methods, high accessibility, and high feasibility for powering wearable sensors and electronics. The foam and e-textile are used as the two active tribomaterials for energy harvester design with the consideration of flexibility and wearability. A calibration platform is also developed to quantify the input mechanical power and power efficiency. The performance of the WearETE system for human motion scavenging is validated and calibrated through experiments. The results show that the wearable triboelectric energy harvester can generate over 70 V output voltage which is capable of powering over 52 LEDs simultaneously with a 9 × 9 cm² area. A larger version is able to lighten 190 LEDs during contact-separation process. The WearETE system can generate a maximum power of 4.8113 mW from hand clapping movements under the frequency of 4 Hz. The average power efficiency can be up to 24.94%. The output power harvested by the WearETE system during slow walking is 7.5248 µW. The results show the possibility of powering wearable electronics during human motion. Full article

(This article belongs to the Section Intelligent Sensors)

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19 pages, 6022 KiB

Open AccessArticle

Self-Organizing Peer-To-Peer Middleware for Healthcare Monitoring in Real-Time

by Hyun Ho Kim¹, Hyeong Gon Jo² and Soon Ju Kang^1,*

¹ School of Electronics Engineering, College of IT Engineering, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 702-701, Korea

² Center of Self-Organizing Software-Platform, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 702-701, Korea

Sensors 2017, 17(11), 2650; https://doi.org/10.3390/s17112650 - 17 Nov 2017

Cited by 4 | Viewed by 4698

Abstract

As the number of elderly persons with chronic illnesses increases, a new public infrastructure for their care is becoming increasingly necessary. In particular, technologies that can monitoring bio-signals in real-time have been receiving significant attention. Currently, most healthcare monitoring services are implemented by [...] Read more.

As the number of elderly persons with chronic illnesses increases, a new public infrastructure for their care is becoming increasingly necessary. In particular, technologies that can monitoring bio-signals in real-time have been receiving significant attention. Currently, most healthcare monitoring services are implemented by wireless carrier through centralized servers. These services are vulnerable to data concentration because all data are sent to a remote server. To solve these problems, we propose self-organizing P2P middleware for healthcare monitoring that enables a real-time multi bio-signal streaming without any central server by connecting the caregiver and care recipient. To verify the performance of the proposed middleware, we evaluated the monitoring service matching time based on a monitoring request. We also confirmed that it is possible to provide an effective monitoring service by evaluating the connectivity between Peer-to-Peer and average jitter. Full article

(This article belongs to the Special Issue Smart Sensor Networks and Technology for Healthcare Monitoring and Decision Making)

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17 pages, 3954 KiB

Open AccessArticle

A High-Performance Portable Transient Electro-Magnetic Sensor for Unexploded Ordnance Detection

by Haofeng Wang¹, Shudong Chen¹, Shuang Zhang^1,*, Zhiwen Yuan², Haiyang Zhang², Dong Fang² and Jun Zhu^2,*

¹ College of Electronic Science and Engineering, Jilin University, Changchun 130012, China

² Science and Technology on Near-Surface Detection Laboratory, Wuxi 214035, China

Sensors 2017, 17(11), 2651; https://doi.org/10.3390/s17112651 - 17 Nov 2017

Cited by 25 | Viewed by 5176

Abstract

Portable transient electromagnetic (TEM) systems can be well adapted to various terrains, including mountainous, woodland, and other complex terrains. They are widely used for the detection of unexploded ordnance (UXO). As the core component of the portable TEM system, the sensor is constructed [...] Read more.

Portable transient electromagnetic (TEM) systems can be well adapted to various terrains, including mountainous, woodland, and other complex terrains. They are widely used for the detection of unexploded ordnance (UXO). As the core component of the portable TEM system, the sensor is constructed with a transmitting coil and a receiving coil. Based on the primary field of the transmitting coil and internal noise of the receiving coil, the design and testing of such a sensor is described in detail. Results indicate that the primary field of the transmitting coil depends on the diameter, mass, and power of the coil. A higher mass–power product and a larger diameter causes a stronger primary field. Reducing the number of turns and increasing the clamp voltage reduces the switch-off time of the transmitting current effectively. Increasing the cross-section of the wire reduces the power consumption, but greatly increases the coil’s weight. The study of the receiving coil shows that the internal noise of the sensor is dominated by the thermal noise of the damping resistor. Reducing the bandwidth of the system and increasing the size of the coil reduces the internal noise effectively. The cross-sectional area and the distance between the sections of the coil have little effect on the internal noise. A less damped state can effectively reduce signal distortion. Finally, a portable TEM sensor with both a transmitting coil (constructed with a diameter, number of turns, and transmitting current of 0.5 m, 30, and 5 A, respectively) and a receiving coil (constructed with a length and resonant frequency of 5.6 cm and 50 kHz, respectively) was built. The agreement between experimental and calculated results confirms the theory used in the sensor design. The responses of an 82 mm mortar shell at different distances were measured and inverted by the differential evolution (DE) algorithm to verify system performance. Results show that the sensor designed in this study can not only detect the 82 mm mortar shell within 1.2 m effectively but also locate the target precisely. Full article

(This article belongs to the Special Issue Magnetic Sensors and Their Applications)

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18 pages, 13616 KiB

Open AccessArticle

Assembled Cantilever Fiber Touch Trigger Probe for Three-Dimensional Measurement of Microstructures

by Limin Zou^*, He Ni, Peng Zhang and Xuemei Ding

Department of Automatic Test and Control, Harbin Institute of Technology, Harbin 150080, China

Sensors 2017, 17(11), 2652; https://doi.org/10.3390/s17112652 - 20 Nov 2017

Cited by 5 | Viewed by 6331

Abstract

In this paper, an assembled cantilever fiber touch trigger probe was developed for three-dimensional measurements of clear microstructures. The probe consists of a shaft assembled vertically to an optical fiber cantilever and a probing sphere located at the free end of the shaft. [...] Read more.

In this paper, an assembled cantilever fiber touch trigger probe was developed for three-dimensional measurements of clear microstructures. The probe consists of a shaft assembled vertically to an optical fiber cantilever and a probing sphere located at the free end of the shaft. The laser is emitted from the free end of the fiber cantilever and converges on the photosensitive surface of the camera through the lens. The position shift of the light spot centroid was used to detect the performance of the optical fiber cantilever, which changed dramatically when the probing sphere touched the objects being measured. Experimental results indicated that the sensing system has sensitivities of 3.32 pixels/μm, 1.35 pixels/μm, and 7.38 pixels/μm in the x, y, and z directions, respectively, and resolutions of 10 nm, 30 nm, and 5 nm were achieved in the x, y, and z, respectively. An experiment on micro slit measurement was performed to verify the high aspect ratio measurement capability of the assembled cantilever fiber (ACF) probe and to calibrate the effective two-point diameter of the probing sphere. The two-point probe sphere diameter was found to be 174.634 μm with a standard uncertainly of 0.045 μm. Full article

(This article belongs to the Special Issue Optical Fiber Sensors 2017)

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20 pages, 1985 KiB

Open AccessArticle

A Game Theoretic Approach for Balancing Energy Consumption in Clustered Wireless Sensor Networks

by Liu Yang^1,*

, Yinzhi Lu², Lian Xiong¹, Yang Tao^1,*

and Yuanchang Zhong³

¹ School of Communication and Information Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China

² School of Electronic Information Engineering, Yangtze Normal University, Chongqing 408100, China

³ College of Communication Engineering, Chongqing University, Chongqing 400044, China

Sensors 2017, 17(11), 2654; https://doi.org/10.3390/s17112654 - 17 Nov 2017

Cited by 36 | Viewed by 5045

Abstract

Clustering is an effective topology control method in wireless sensor networks (WSNs), since it can enhance the network lifetime and scalability. To prolong the network lifetime in clustered WSNs, an efficient cluster head (CH) optimization policy is essential to distribute the energy among [...] Read more.

Clustering is an effective topology control method in wireless sensor networks (WSNs), since it can enhance the network lifetime and scalability. To prolong the network lifetime in clustered WSNs, an efficient cluster head (CH) optimization policy is essential to distribute the energy among sensor nodes. Recently, game theory has been introduced to model clustering. Each sensor node is considered as a rational and selfish player which will play a clustering game with an equilibrium strategy. Then it decides whether to act as the CH according to this strategy for a tradeoff between providing required services and energy conservation. However, how to get the equilibrium strategy while maximizing the payoff of sensor nodes has rarely been addressed to date. In this paper, we present a game theoretic approach for balancing energy consumption in clustered WSNs. With our novel payoff function, realistic sensor behaviors can be captured well. The energy heterogeneity of nodes is considered by incorporating a penalty mechanism in the payoff function, so the nodes with more energy will compete for CHs more actively. We have obtained the Nash equilibrium (NE) strategy of the clustering game through convex optimization. Specifically, each sensor node can achieve its own maximal payoff when it makes the decision according to this strategy. Through plenty of simulations, our proposed game theoretic clustering is proved to have a good energy balancing performance and consequently the network lifetime is greatly enhanced. Full article

(This article belongs to the Collection Smart Communication Protocols and Algorithms for Sensor Networks)

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11 pages, 1136 KiB

Open AccessArticle

Laser-Induced Breakdown Spectroscopy for Rapid Discrimination of Heavy-Metal-Contaminated Seafood Tegillarca granosa

by Guoli Ji^1,2, Pengchao Ye¹, Yijian Shi^3,*, Leiming Yuan³

, Xiaojing Chen³, Mingshun Yuan¹, Dehua Zhu⁴, Xi Chen³, Xinyu Hu³ and Jing Jiang^5,6,*

¹ Department of Automation, Xiamen University, Xiamen 361005, China

² Innovation Center for Cell Signaling Network, Xiamen University, Xiamen 361102, China

³ College of Physics and Electronic Engineering Information, Wenzhou University, Wenzhou 325035, China

⁴ College of Mechanical and Electrical Engineering, Wenzhou University, Wenzhou 325035, China

⁵ LifeFoundry, Inc., Champaign, IL 61820, USA

⁶ Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA

Sensors 2017, 17(11), 2655; https://doi.org/10.3390/s17112655 - 17 Nov 2017

Cited by 20 | Viewed by 6034

Abstract

Tegillarca granosa samples contaminated artificially by three kinds of toxic heavy metals including zinc (Zn), cadmium (Cd), and lead (Pb) were attempted to be distinguished using laser-induced breakdown spectroscopy (LIBS) technology and pattern recognition methods in this study. The measured spectra were firstly [...] Read more.

Tegillarca granosa samples contaminated artificially by three kinds of toxic heavy metals including zinc (Zn), cadmium (Cd), and lead (Pb) were attempted to be distinguished using laser-induced breakdown spectroscopy (LIBS) technology and pattern recognition methods in this study. The measured spectra were firstly processed by a wavelet transform algorithm (WTA), then the generated characteristic information was subsequently expressed by an information gain algorithm (IGA). As a result, 30 variables obtained were used as input variables for three classifiers: partial least square discriminant analysis (PLS-DA), support vector machine (SVM), and random forest (RF), among which the RF model exhibited the best performance, with 93.3% discrimination accuracy among those classifiers. Besides, the extracted characteristic information was used to reconstruct the original spectra by inverse WTA, and the corresponding attribution of the reconstructed spectra was then discussed. This work indicates that the healthy shellfish samples of Tegillarca granosa could be distinguished from the toxic heavy-metal-contaminated ones by pattern recognition analysis combined with LIBS technology, which only requires minimal pretreatments. Full article

(This article belongs to the Special Issue Surface Plasmon Resonance Sensing)

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25 pages, 1955 KiB

Open AccessArticle

Model-Based Heterogeneous Data Fusion for Reliable Force Estimation in Dynamic Structures under Uncertainties

by Babak Khodabandeloo, Dyan Melvin and Hongki Jo^*

Civil Engineering and Engineering Mechanics, The University of Arizona, Tucson, AZ 85721, USA

Sensors 2017, 17(11), 2656; https://doi.org/10.3390/s17112656 - 17 Nov 2017

Cited by 16 | Viewed by 5529

Abstract

Direct measurements of external forces acting on a structure are infeasible in many cases. The Augmented Kalman Filter (AKF) has several attractive features that can be utilized to solve the inverse problem of identifying applied forces, as it requires the dynamic model and [...] Read more.

Direct measurements of external forces acting on a structure are infeasible in many cases. The Augmented Kalman Filter (AKF) has several attractive features that can be utilized to solve the inverse problem of identifying applied forces, as it requires the dynamic model and the measured responses of structure at only a few locations. But, the AKF intrinsically suffers from numerical instabilities when accelerations, which are the most common response measurements in structural dynamics, are the only measured responses. Although displacement measurements can be used to overcome the instability issue, the absolute displacement measurements are challenging and expensive for full-scale dynamic structures. In this paper, a reliable model-based data fusion approach to reconstruct dynamic forces applied to structures using heterogeneous structural measurements (i.e., strains and accelerations) in combination with AKF is investigated. The way of incorporating multi-sensor measurements in the AKF is formulated. Then the formulation is implemented and validated through numerical examples considering possible uncertainties in numerical modeling and sensor measurement. A planar truss example was chosen to clearly explain the formulation, while the method and formulation are applicable to other structures as well. Full article

(This article belongs to the Special Issue Advances in Multi-Sensor Information Fusion: Theory and Applications 2017)

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11 pages, 3408 KiB

Open AccessArticle

The Design and Characterization of a Prototype Wideband Voltage Sensor Based on a Resistive Divider

by Fernando Garnacho^*, Abderrahim Khamlichi and Jorge Rovira

Laboratorio Central Oficial de Electrotecnia (LCOE), Fundación para el Fomento de la Innovación Industrial (FFII), c/Eric Kandel, 1, 28906 Getafe, Madrid, Spain

Sensors 2017, 17(11), 2657; https://doi.org/10.3390/s17112657 - 17 Nov 2017

Cited by 17 | Viewed by 6680

Abstract

The most important advantage of voltage dividers over traditional voltage transformers is that voltage dividers do not have an iron core with non-linear hysteresis characteristics. The voltage dividers have a linear behavior with respect to over-voltages and a flat frequency response larger frequency [...] Read more.

The most important advantage of voltage dividers over traditional voltage transformers is that voltage dividers do not have an iron core with non-linear hysteresis characteristics. The voltage dividers have a linear behavior with respect to over-voltages and a flat frequency response larger frequency range. The weak point of a voltage divider is the influence of external high-voltage (HV) and earth parts in its vicinity. Electrical fields arising from high voltages in neighboring phases and from ground conductors and structures are one of their main sources for systematic measurement errors. This paper describes a shielding voltage divider for a 24 kV medium voltage network insulated in SF6 composed of two resistive-capacitive dividers, one integrated within the other, achieving a flat frequency response up to 10 kHz for ratio error and up to 5 kHz for phase displacement error. The metal shielding improves its immunity against electric and magnetic fields. The characterization performed on the built-in voltage sensor shows an accuracy class of 0.2 for a frequency range from 20 Hz to 5 kHz and a class of 0.5 for 1 Hz up to 20 Hz. A low temperature effect is also achieved for operation conditions of MV power grids. Full article

(This article belongs to the Section Physical Sensors)

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23 pages, 1522 KiB

Open AccessArticle

Local Homing Navigation Based on the Moment Model for Landmark Distribution and Features

by Changmin Lee^† and DaeEun Kim^*,†

¹ School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Korea

^† Current address: 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.

Sensors 2017, 17(11), 2658; https://doi.org/10.3390/s17112658 - 17 Nov 2017

Cited by 7 | Viewed by 4538

Abstract

[-10]For local homing navigation, an agent is supposed to return home based on the surrounding environmental information. According to the snapshot model, the home snapshot and the current view are compared to determine the homing direction. In this paper, we propose a novel [...] Read more.

[-10]For local homing navigation, an agent is supposed to return home based on the surrounding environmental information. According to the snapshot model, the home snapshot and the current view are compared to determine the homing direction. In this paper, we propose a novel homing navigation method using the moment model. The suggested moment model also follows the snapshot theory to compare the home snapshot and the current view, but the moment model defines a moment of landmark inertia as the sum of the product of the feature of the landmark particle with the square of its distance. The method thus uses range values of landmarks in the surrounding view and the visual features. The center of the moment can be estimated as the reference point, which is the unique convergence point in the moment potential from any view. The homing vector can easily be extracted from the centers of the moment measured at the current position and the home location. The method effectively guides homing direction in real environments, as well as in the simulation environment. In this paper, we take a holistic approach to use all pixels in the panoramic image as landmarks and use the RGB color intensity for the visual features in the moment model in which a set of three moment functions is encoded to determine the homing vector. We also tested visual homing or the moment model with only visual features, but the suggested moment model with both the visual feature and the landmark distance shows superior performance. We demonstrate homing performance with various methods classified by the status of the feature, the distance and the coordinate alignment. Full article

(This article belongs to the Special Issue Sensors and Sensing in Indoor Localization, Tracking, Navigation and Activity Monitoring)

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9 pages, 3784 KiB

Open AccessArticle

A Dual-Polymer Fiber Fizeau Interferometer for Simultaneous Measurement of Relative Humidity and Temperature

by Chao-Tsung Ma¹, Yu-Wei Chang², Yuan-Jie Yang² and Cheng-Ling Lee^2,*

¹ Department of Electrical Engineering, National United University, Miaoli 36003, Taiwan

² Department of Electro-Optical Engineering, National United University, Miaoli 36003, Taiwan

Sensors 2017, 17(11), 2659; https://doi.org/10.3390/s17112659 - 17 Nov 2017

Cited by 21 | Viewed by 4407

Abstract

This paper presents a novel design method in which a dual-polymer fiber Fizeau interferometer (DPFFI) is proposed for simultaneously measuring relative humidity (RH) and temperature (T). Since the polymer is intrinsically highly sensitive to both RH and T, the polymer fiber Fizeau interferometer [...] Read more.

This paper presents a novel design method in which a dual-polymer fiber Fizeau interferometer (DPFFI) is proposed for simultaneously measuring relative humidity (RH) and temperature (T). Since the polymer is intrinsically highly sensitive to both RH and T, the polymer fiber Fizeau interferometer (PFFI) exhibits cross-sensitivity of RH and T. In general, it is difficult to demodulate the optical responses from both variations of RH and T using a single PFFI. If two PFFIs with different structures are combined, they will individually exhibit distinct sensitivity responses with respect to RH and T, respectively. The technical problem of analyzing multiple interferences of the optical spectra of the DPFFI and the individual sensitivity of RH and T to each PFFI is obtained using the fast Fourier transform (FFT). A mathematical method is applied to solve the simultaneous equations of the DPFFI, so that the two variables RH and T can be determined at the same time. Experimental results, indicating good sensitivity and accuracy, with small measurement errors (average errors of ~1.46 °C and ~1.48%, respectively), are shown, determining the feasibility, and verifying the effectiveness, of the proposed DPFFI sensor. Full article

(This article belongs to the Section Physical Sensors)

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14 pages, 3697 KiB

Open AccessArticle

Wireless Monitoring of Induction Machine Rotor Physical Variables

by Jefferson Doolan Fernandes², Francisco Elvis Carvalho Souza¹, Glauco George Cipriano Maniçoba^1,*

, Andrés Ortiz Salazar¹

and José Alvaro De Paiva²

¹ Programa de Pós-Graduação em Engenharia Elétrica, Universidade Federal do Rio Grande do Norte, Campus Universitário Lagoa Nova, Centro de Tecnologia, CEP 59078-970 Natal, Brazil

² Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Norte, Campus Parnamirim, CEP 59143-455 Parnamirim, Brazil

Sensors 2017, 17(11), 2660; https://doi.org/10.3390/s17112660 - 18 Nov 2017

Cited by 11 | Viewed by 5144

Abstract

With the widespread use of electric machines, there is a growing need to extract information from the machines to improve their control systems and maintenance management. The present work shows the development of an embedded system to perform the monitoring of the rotor [...] Read more.

With the widespread use of electric machines, there is a growing need to extract information from the machines to improve their control systems and maintenance management. The present work shows the development of an embedded system to perform the monitoring of the rotor physical variables of a squirrel cage induction motor. The system is comprised of: a circuit to acquire desirable rotor variable(s) and value(s) that send it to the computer; a rectifier and power storage circuit that converts an alternating current in a continuous current but also stores energy for a certain amount of time to wait for the motor’s shutdown; and a magnetic generator that harvests energy from the rotating field to power the circuits mentioned above. The embedded system is set on the rotor of a 5 HP squirrel cage induction motor, making it difficult to power the system because it is rotating. This problem can be solved with the construction of a magnetic generator device to avoid the need of using batteries or collector rings and will send data to the computer using a wireless NRF24L01 module. For the proposed system, initial validation tests were made using a temperature sensor (DS18b20), as this variable is known as the most important when identifying the need for maintenance and control systems. Few tests have shown promising results that, with further improvements, can prove the feasibility of using sensors in the rotor. Full article

(This article belongs to the Special Issue Wireless Rechargeable Sensor Networks)

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15 pages, 5936 KiB

Open AccessArticle

Magnetic Flux Distribution of Linear Machines with Novel Three-Dimensional Hybrid Magnet Arrays

by Nan Yao, Liang Yan^*, Tianyi Wang and Shaoping Wang

School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China

Sensors 2017, 17(11), 2662; https://doi.org/10.3390/s17112662 - 18 Nov 2017

Cited by 4 | Viewed by 6050

Abstract

The objective of this paper is to propose a novel tubular linear machine with hybrid permanent magnet arrays and multiple movers, which could be employed for either actuation or sensing technology. The hybrid magnet array produces flux distribution on both sides of windings, [...] Read more.

The objective of this paper is to propose a novel tubular linear machine with hybrid permanent magnet arrays and multiple movers, which could be employed for either actuation or sensing technology. The hybrid magnet array produces flux distribution on both sides of windings, and thus helps to increase the signal strength in the windings. The multiple movers are important for airspace technology, because they can improve the system’s redundancy and reliability. The proposed design concept is presented, and the governing equations are obtained based on source free property and Maxwell equations. The magnetic field distribution in the linear machine is thus analytically formulated by using Bessel functions and harmonic expansion of magnetization vector. Numerical simulation is then conducted to validate the analytical solutions of the magnetic flux field. It is proved that the analytical model agrees with the numerical results well. Therefore, it can be utilized for the formulation of signal or force output subsequently, depending on its particular implementation. Full article

(This article belongs to the Special Issue Mechatronic Systems for Automatic Vehicles)

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13 pages, 4430 KiB

Open AccessArticle

System Modeling of a MEMS Vibratory Gyroscope and Integration to Circuit Simulation

by Hyukjin J. Kwon

, Seyeong Seok and Geunbae Lim^*

Department of Mechanical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, Korea

Sensors 2017, 17(11), 2663; https://doi.org/10.3390/s17112663 - 18 Nov 2017

Cited by 19 | Viewed by 9423

Abstract

Recently, consumer applications have dramatically created the demand for low-cost and compact gyroscopes. Therefore, on the basis of microelectromechanical systems (MEMS) technology, many gyroscopes have been developed and successfully commercialized. A MEMS gyroscope consists of a MEMS device and an electrical circuit for [...] Read more.

Recently, consumer applications have dramatically created the demand for low-cost and compact gyroscopes. Therefore, on the basis of microelectromechanical systems (MEMS) technology, many gyroscopes have been developed and successfully commercialized. A MEMS gyroscope consists of a MEMS device and an electrical circuit for self-oscillation and angular-rate detection. Since the MEMS device and circuit are interactively related, the entire system should be analyzed together to design or test the gyroscope. In this study, a MEMS vibratory gyroscope is analyzed based on the system dynamic modeling; thus, it can be mathematically expressed and integrated into a circuit simulator. A behavioral simulation of the entire system was conducted to prove the self-oscillation and angular-rate detection and to determine the circuit parameters to be optimized. From the simulation, the operating characteristic according to the vacuum pressure and scale factor was obtained, which indicated similar trends compared with those of the experimental results. The simulation method presented in this paper can be generalized to a wide range of MEMS devices. Full article

(This article belongs to the Special Issue Inertial Sensors for Positioning and Navigation)

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14 pages, 2337 KiB

Open AccessArticle

Assessing Crop Coefficients for Natural Vegetated Areas Using Satellite Data and Eddy Covariance Stations

by Chiara Corbari^1,*, Giovanni Ravazzani¹

, Marta Galvagno², Edoardo Cremonese² and Marco Mancini¹

¹ Department of Civil and Environmental Engineering, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milan, Italy

² Environmental Protection Agency of Aosta Valley, Climate Change Unit, 11100 Aosta, Italy

Sensors 2017, 17(11), 2664; https://doi.org/10.3390/s17112664 - 18 Nov 2017

Cited by 24 | Viewed by 5727

Abstract

The Food and Agricultural Organization (FAO) method for potential evapotranspiration assessment is based on the crop coefficient, which allows one to relate the reference evapotranspiration of well irrigated grass to the potential evapotranspiration of specific crops. The method was originally developed for cultivated [...] Read more.

The Food and Agricultural Organization (FAO) method for potential evapotranspiration assessment is based on the crop coefficient, which allows one to relate the reference evapotranspiration of well irrigated grass to the potential evapotranspiration of specific crops. The method was originally developed for cultivated species based on lysimeter measurements of potential evapotranspiration. Not many applications to natural vegetated areas exist due to the lack of available data for these species. In this paper we investigate the potential of using evapotranspiration measurements acquired by micrometeorological stations for the definition of crop coefficient functions of natural vegetated areas and extrapolation to ungauged sites through remotely sensed data. Pastures, deciduous and evergreen forests have been considered and lower crop coefficient values are found with respect to FAO data. Full article

(This article belongs to the Special Issue Earth Observation and In-Situ Sensing for Risk Assessment from Natural Threats)

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10 pages, 2248 KiB

Open AccessArticle

Adsorptive Stripping Voltammetric Determination of Amaranth and Tartrazine in Drinks and Gelatins Using a Screen-Printed Carbon Electrode

by Yeny Perdomo¹, Verónica Arancibia^2,*, Olimpo García-Beltrán¹

and Edgar Nagles^1,*

¹ Facultad de Ciencias Naturales y Matemáticas, Universidad de Ibagué, Carrera 22 Calle 67, Ibagué 730001, Colombia

² Facultad de Química, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Santiago 7820436, Chile

Sensors 2017, 17(11), 2665; https://doi.org/10.3390/s17112665 - 18 Nov 2017

Cited by 26 | Viewed by 5202

Abstract

A fast, sensitive, and selective method for the simultaneous determination of one pair of synthetic colorants commonly found mixed in food products, Amaranth (AM) and Tartrazine (TZ), based on their adsorption and oxidation on a screen-printed electrode (SPE) is presented. The variation of [...] Read more.

A fast, sensitive, and selective method for the simultaneous determination of one pair of synthetic colorants commonly found mixed in food products, Amaranth (AM) and Tartrazine (TZ), based on their adsorption and oxidation on a screen-printed electrode (SPE) is presented. The variation of peak current with pH, supporting electrolyte, adsorption time, and adsorption potential were optimized using square wave adsorptive voltammetry. The optimal conditions were found to be: pH 3.2 (PBS), E_ads 0.00 V, and t_ads 30 s. Under these conditions, the AM and TZ signals were observed at 0.56 and 0.74 V, respectively. A linear response were found over the 0.15 to 1.20 µmol L⁻¹ and 0.15 to 0.80 µmol L⁻¹ concentrations, with detection limits (3σ/slope) of 26 and 70 nmol L⁻¹ for AM and TZ, respectively. Reproducibility for 17.7 µmol L^–1 AM and TZ solutions were 2.5 and 3.0% (n = 7), respectively, using three different electrodes. The method was validated by determining AM and TZ in spiked tap water and unflavored gelatin spiked with AM and TZ. Because a beverage containing both AM and TZ was not found, the method was applied to the determination of AM in a kola soft drink and TZ in an orange jelly and a soft drink powder. Full article

(This article belongs to the Special Issue Screen-Printed Electrodes)

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25 pages, 1809 KiB

Open AccessArticle

Survey on the Performance of Source Localization Algorithms

by José Manuel Fresno¹, Guillermo Robles^1,*

, Juan Manuel Martínez-Tarifa¹

and Brian G. Stewart^2,*

¹ Department of Electrical Engineering, Universidad Carlos III de Madrid, Avda, Universidad, 30, Leganés, 28911 Madrid, Spain

² Department of Electronic and Electrical Engineering, University of Strathclyde, 204 George Street, Glasgow G1 1XW, UK

Sensors 2017, 17(11), 2666; https://doi.org/10.3390/s17112666 - 18 Nov 2017

Cited by 43 | Viewed by 6510

Abstract

The localization of emitters using an array of sensors or antennas is a prevalent issue approached in several applications. There exist different techniques for source localization, which can be classified into multilateration, received signal strength (RSS) and proximity methods. The performance of multilateration [...] Read more.

The localization of emitters using an array of sensors or antennas is a prevalent issue approached in several applications. There exist different techniques for source localization, which can be classified into multilateration, received signal strength (RSS) and proximity methods. The performance of multilateration techniques relies on measured time variables: the time of flight (ToF) of the emission from the emitter to the sensor, the time differences of arrival (TDoA) of the emission between sensors and the pseudo-time of flight (pToF) of the emission to the sensors. The multilateration algorithms presented and compared in this paper can be classified as iterative and non-iterative methods. Both standard least squares (SLS) and hyperbolic least squares (HLS) are iterative and based on the Newton–Raphson technique to solve the non-linear equation system. The metaheuristic technique particle swarm optimization (PSO) used for source localisation is also studied. This optimization technique estimates the source position as the optimum of an objective function based on HLS and is also iterative in nature. Three non-iterative algorithms, namely the hyperbolic positioning algorithms (HPA), the maximum likelihood estimator (MLE) and Bancroft algorithm, are also presented. A non-iterative combined algorithm, MLE-HLS, based on MLE and HLS, is further proposed in this paper. The performance of all algorithms is analysed and compared in terms of accuracy in the localization of the position of the emitter and in terms of computational time. The analysis is also undertaken with three different sensor layouts since the positions of the sensors affect the localization; several source positions are also evaluated to make the comparison more robust. The analysis is carried out using theoretical time differences, as well as including errors due to the effect of digital sampling of the time variables. It is shown that the most balanced algorithm, yielding better results than the other algorithms in terms of accuracy and short computational time, is the combined MLE-HLS algorithm. Full article

(This article belongs to the Special Issue UHF and RF Sensor Technology for Partial Discharge Detection)

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17 pages, 520 KiB

Open AccessArticle

Random Access Performance of Distributed Sensors Attacked by Unknown Jammers

by Dae-Kyo Jeong¹

, Jung-Hwa Wui² and Dongwoo Kim^3,*

¹ Department of Electronics and Communication Engineering, Hanyang University, Ansan 15588, Korea

² Research Institute of Engineering and Technology, Hanyang University, Ansan 15588, Korea

³ Division of Electrical Engineering, Hanyang University, Ansan 15588, Korea

Sensors 2017, 17(11), 2667; https://doi.org/10.3390/s17112667 - 18 Nov 2017

Cited by 3 | Viewed by 3521

Abstract

In this paper, we model and investigate the random access (RA) performance of sensor nodes (SN) in a wireless sensor network (WSN). In the WSN, a central head sensor (HS) collects the information from distributed SNs, and jammers disturb the information transmission primarily [...] Read more.

In this paper, we model and investigate the random access (RA) performance of sensor nodes (SN) in a wireless sensor network (WSN). In the WSN, a central head sensor (HS) collects the information from distributed SNs, and jammers disturb the information transmission primarily by generating interference. In this paper, two jamming attacks are considered: power and code jamming. Power jammers (if they are friendly jammers) generate noises and, as a result, degrade the quality of the signal from SNs. Power jamming is equally harmful to all the SNs that are accessing HS and simply induces denial of service (DoS) without any need to hack HS or SNs. On the other hand, code jammers mimic legitimate SNs by sending fake signals and thus need to know certain system parameters that are used by the legitimate SNs. As a result of code jamming, HS falsely allocates radio resources to SNs. The code jamming hence increases the failure probability in sending the information messages, as well as misleads the usage of radio resources. In this paper, we present the probabilities of successful preamble transmission with power ramping according to the jammer types and provide the resulting throughput and delay of information transmission by SNs, respectively. The effect of two jamming attacks on the RA performances is compared with numerical investigation. The results show that, compared to RA without jammers, power and code jamming degrade the throughput by up to 30.3% and 40.5%, respectively, while the delay performance by up to 40.1% and 65.6%, respectively. Full article

(This article belongs to the Section Sensor Networks)

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23 pages, 11751 KiB

Open AccessArticle

An Enhanced Non-Coherent Pre-Filter Design for Tracking Error Estimation in GNSS Receivers

by Zhibin Luo^*, Jicheng Ding^*, Lin Zhao and Mouyan Wu

College of Automation, Harbin Engineering University, Harbin 150001, China

Sensors 2017, 17(11), 2668; https://doi.org/10.3390/s17112668 - 18 Nov 2017

Cited by 11 | Viewed by 4231

Abstract

Tracking error estimation is of great importance in global navigation satellite system (GNSS) receivers. Any inaccurate estimation for tracking error will decrease the signal tracking ability of signal tracking loops and the accuracies of position fixing, velocity determination, and timing. Tracking error estimation [...] Read more.

Tracking error estimation is of great importance in global navigation satellite system (GNSS) receivers. Any inaccurate estimation for tracking error will decrease the signal tracking ability of signal tracking loops and the accuracies of position fixing, velocity determination, and timing. Tracking error estimation can be done by traditional discriminator, or Kalman filter-based pre-filter. The pre-filter can be divided into two categories: coherent and non-coherent. This paper focuses on the performance improvements of non-coherent pre-filter. Firstly, the signal characteristics of coherent and non-coherent integration—which are the basis of tracking error estimation—are analyzed in detail. After that, the probability distribution of estimation noise of four-quadrant arctangent (ATAN2) discriminator is derived according to the mathematical model of coherent integration. Secondly, the statistical property of observation noise of non-coherent pre-filter is studied through Monte Carlo simulation to set the observation noise variance matrix correctly. Thirdly, a simple fault detection and exclusion (FDE) structure is introduced to the non-coherent pre-filter design, and thus its effective working range for carrier phase error estimation extends from (−0.25 cycle, 0.25 cycle) to (−0.5 cycle, 0.5 cycle). Finally, the estimation accuracies of discriminator, coherent pre-filter, and the enhanced non-coherent pre-filter are evaluated comprehensively through the carefully designed experiment scenario. The pre-filter outperforms traditional discriminator in estimation accuracy. In a highly dynamic scenario, the enhanced non-coherent pre-filter provides accuracy improvements of 41.6%, 46.4%, and 50.36% for carrier phase error, carrier frequency error, and code phase error estimation, respectively, when compared with coherent pre-filter. The enhanced non-coherent pre-filter outperforms the coherent pre-filter in code phase error estimation when carrier-to-noise density ratio is less than 28.8 dB-Hz, in carrier frequency error estimation when carrier-to-noise density ratio is less than 20 dB-Hz, and in carrier phase error estimation when carrier-to-noise density belongs to (15, 23) dB-Hz

\cup

(26, 50) dB-Hz. Full article

(This article belongs to the Section Remote Sensors)

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14 pages, 18356 KiB

Open AccessArticle

A Subnano-g Electrostatic Force-Rebalanced Flexure Accelerometer for Gravity Gradient Instruments

by Shitao Yan¹, Yafei Xie¹, Mengqi Zhang¹, Zhongguang Deng¹ and Liangcheng Tu^1,2,*

¹ MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics, School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China

² Institute of Geophysics, Huazhong University of Science and Technology, Wuhan 430074, China

Sensors 2017, 17(11), 2669; https://doi.org/10.3390/s17112669 - 18 Nov 2017

Cited by 36 | Viewed by 7840

Abstract

A subnano-g electrostatic force-rebalanced flexure accelerometer is designed for the rotating accelerometer gravity gradient instrument. This accelerometer has a large proof mass, which is supported inversely by two pairs of parallel leaf springs and is centered between two fixed capacitor plates. This novel [...] Read more.

A subnano-g electrostatic force-rebalanced flexure accelerometer is designed for the rotating accelerometer gravity gradient instrument. This accelerometer has a large proof mass, which is supported inversely by two pairs of parallel leaf springs and is centered between two fixed capacitor plates. This novel design enables the proof mass to move exactly along the sensitive direction and exhibits a high rejection ratio at its cross-axis directions. Benefiting from large proof mass, high vacuum packaging, and air-tight sealing, the thermal Brownian noise of the accelerometer is lowered down to less than 0.2

ng / \sqrt{Hz}

with a quality factor of 15 and a natural resonant frequency of about

7.4 Hz

. The accelerometer’s designed measurement range is about ±1 mg. Based on the correlation analysis between a commercial triaxial seismometer and our accelerometer, the demonstrated self-noise of our accelerometers is reduced to lower than 0.3

ng / \sqrt{Hz}

over the frequency ranging from 0.2 to 2 Hz, which meets the requirement of the rotating accelerometer gravity gradiometer. Full article

(This article belongs to the Section Physical Sensors)

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19 pages, 2476 KiB

Open AccessArticle

Stochastic Integration H_∞ Filter for Rapid Transfer Alignment of INS

by Dapeng Zhou^1,* and Lei Guo^2,3

¹ School of Instrumentation Science and Opto-Electronics Engineering, Beihang University, Beijing 100191, China

² Science and Technology on Aircraft Control Laboratory, Beihang University, Beijing 100191, China

³ School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China

Sensors 2017, 17(11), 2670; https://doi.org/10.3390/s17112670 - 18 Nov 2017

Cited by 3 | Viewed by 3968

Abstract

The performance of an inertial navigation system (INS) operated on a moving base greatly depends on the accuracy of rapid transfer alignment (RTA). However, in practice, the coexistence of large initial attitude errors and uncertain observation noise statistics poses a great challenge for [...] Read more.

The performance of an inertial navigation system (INS) operated on a moving base greatly depends on the accuracy of rapid transfer alignment (RTA). However, in practice, the coexistence of large initial attitude errors and uncertain observation noise statistics poses a great challenge for the estimation accuracy of misalignment angles. This study aims to develop a novel robust nonlinear filter, namely the stochastic integration H

_{\infty}

filter (SIH

_{\infty}

F) for improving both the accuracy and robustness of RTA. In this new nonlinear H

_{\infty}

filter, the stochastic spherical-radial integration rule is incorporated with the framework of the derivative-free H

_{\infty}

filter for the first time, and the resulting SIH

_{\infty}

F simultaneously attenuates the negative effect in estimations caused by significant nonlinearity and large uncertainty. Comparisons between the SIH

_{\infty}

F and previously well-known methodologies are carried out by means of numerical simulation and a van test. The results demonstrate that the newly-proposed method outperforms the cubature H

_{\infty}

filter. Moreover, the SIH

_{\infty}

F inherits the benefit of the traditional stochastic integration filter, but with more robustness in the presence of uncertainty. Full article

(This article belongs to the Special Issue Inertial Sensors for Positioning and Navigation)

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16 pages, 7096 KiB

Open AccessArticle

Two-Dimensional Micro-/Nanoradian Angle Generator with High Resolution and Repeatability Based on Piezo-Driven Double-Axis Flexure Hinge and Three Capacitive Sensors

by Xinran Tan, Fan Zhu^*, Chao Wang, Yang Yu, Jian Shi, Xue Qi, Feng Yuan and Jiubin Tan^*

Center of Ultra-precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, Harbin 150080, China

Sensors 2017, 17(11), 2672; https://doi.org/10.3390/s17112672 - 19 Nov 2017

Cited by 11 | Viewed by 7158

Abstract

This study presents a two-dimensional micro-/nanoradian angle generator (2D-MNAG) that achieves high angular displacement resolution and repeatability using a piezo-driven flexure hinge for two-dimensional deflections and three capacitive sensors for output angle monitoring and feedback control. The principal error of the capacitive sensor [...] Read more.

This study presents a two-dimensional micro-/nanoradian angle generator (2D-MNAG) that achieves high angular displacement resolution and repeatability using a piezo-driven flexure hinge for two-dimensional deflections and three capacitive sensors for output angle monitoring and feedback control. The principal error of the capacitive sensor for precision microangle measurement is analyzed and compensated for; so as to achieve a high angle output resolution of 10 nrad (0.002 arcsec) and positioning repeatability of 120 nrad (0.024 arcsec) over a large angular range of ±4363 μrad (±900 arcsec) for the 2D-MNAG. The impact of each error component, together with the synthetic error of the 2D-MNAG after principal error compensation are determined using Monte Carlo simulation for further improvement of the 2D-MNAG. Full article

(This article belongs to the Special Issue Piezoelectric Micro- and Nano-Devices)

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11 pages, 3084 KiB

Open AccessArticle

Optimized Lateral Flow Immunoassay Reader for the Detection of Infectious Diseases in Developing Countries

by Evdokia Pilavaki^* and Andreas Demosthenous

Department of Electronic and Electrical Engineering, University College London, Torrington Place, WC1E 7JE London, UK

Sensors 2017, 17(11), 2673; https://doi.org/10.3390/s17112673 - 20 Nov 2017

Cited by 25 | Viewed by 8116

Abstract

Detection and control of infectious diseases is a major problem, especially in developing countries. Lateral flow immunoassays can be used with great success for the detection of infectious diseases. However, for the quantification of their results an electronic reader is required. This paper [...] Read more.

Detection and control of infectious diseases is a major problem, especially in developing countries. Lateral flow immunoassays can be used with great success for the detection of infectious diseases. However, for the quantification of their results an electronic reader is required. This paper presents an optimized handheld electronic reader for developing countries. It features a potentially low-cost, low-power, battery-operated device with no added optical accessories. The operation of this proof of concept device is based on measuring the reflected light from the lateral flow immunoassay and translating it into the concentration of the specific analyte of interest. Characterization of the surface of the lateral flow immunoassay has been performed in order to accurately model its response to the incident light. Ray trace simulations have been performed to optimize the system and achieve maximum sensitivity by placing all the components in optimum positions. A microcontroller enables all the signal processing to be performed on the device and a Bluetooth module allows transmission of the results wirelessly to a mobile phone app. Its performance has been validated using lateral flow immunoassays with influenza A nucleoprotein in the concentration range of 0.5 ng/mL to 200 ng/mL. Full article

(This article belongs to the Special Issue Sensors for Health Monitoring and Disease Diagnosis)

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9 pages, 2546 KiB

Open AccessArticle

A Loop All-Fiber Current Sensor Based on Single-Polarization Single-Mode Couplers

by Hao Zhang^1,*

, Junzhen Jiang², Yu Zhang¹, Huaixi Chen³, Na Zhao⁴, Lingyan Lin¹ and Yishen Qiu^2,*

¹ Department of Electronic Information Science, Fujian Jiangxia University, Fuzhou 350007, China

² Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou 350007, China

³ Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China

⁴ Academy of OPTO-electronics, Chinese Academy of Science, Beijing 100094, China

Sensors 2017, 17(11), 2674; https://doi.org/10.3390/s17112674 - 20 Nov 2017

Cited by 11 | Viewed by 4807

Abstract

Low current sensitivity and insufficient system stability are two key problems in all-fiber current sensor (AFCS) studies. In order to solve the two problems, a novel AFCS combining single-polarization single-mode (SPSM) couplers and a loop structure is presented in this paper with a [...] Read more.

Low current sensitivity and insufficient system stability are two key problems in all-fiber current sensor (AFCS) studies. In order to solve the two problems, a novel AFCS combining single-polarization single-mode (SPSM) couplers and a loop structure is presented in this paper with a design that incorporates the advantages of both SPSM couplers and a loop structure. SPSM couplers are shown to simplify the AFCS system and reduce the risk of interference, and the loop structure can enhance the current sensitivity. Both theory and experiment prove that the new AFCS can simultaneously overcome two prevalent obstacles of low current sensitivity and low stability. Full article

(This article belongs to the Section Physical Sensors)

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8 pages, 3197 KiB

Open AccessArticle

A Dual Band Frequency Reconfigurable Origami Magic Cube Antenna for Wireless Sensor Network Applications

by Syed Imran Hussain Shah and Sungjoon Lim^*

School of Electrical and Electronics Engineering, College of Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 156-756, Korea

Sensors 2017, 17(11), 2675; https://doi.org/10.3390/s17112675 - 20 Nov 2017

Cited by 25 | Viewed by 7116

Abstract

In this paper, a novel dual band frequency reconfigurable antenna using an origami magic cube is proposed for wireless sensor network (WSN) applications. The proposed origami antenna consists of a meandered monopole folded onto three sides of the magic cube. A microstrip open-ended [...] Read more.

In this paper, a novel dual band frequency reconfigurable antenna using an origami magic cube is proposed for wireless sensor network (WSN) applications. The proposed origami antenna consists of a meandered monopole folded onto three sides of the magic cube. A microstrip open-ended stub is loaded on the meandered monopole. The proposed origami magic cube can be mechanically folded and unfolded. The proposed antenna operates at 1.57 GHZ and 2.4 GHz in the folded state. In the unfolded state, the proposed antenna operates at 900 MHz and 2.3 GHz. The resonant frequency of the second band can be tunable by varying the length and position of the open stub. The origami magic cube is built on paper. Its performance is numerically and experimentally demonstrated from S-parameters and radiation patterns. The measured 10 dB impedance bandwidth of the proposed origami antenna is 18% (900–1120 MHz) and 15% (2.1–2.45 GHz) for the unfolded state and 20% (1.3–1.6 GHz) and 14% (2.3–2.5 GHz) for the folded state. The measured peak gain at 900 MHz and 2.3 GHz are 1.1 dBi and 2.32 dBi, respectively, in the unfolded state. The measured peak gain at 1.5 GHz and 2.4 GHz are 3.28 dBi and 1.98 dBi, respectively, in the folded state. Full article

(This article belongs to the Special Issue Recent Advances in Front-End Designs for Sensors and Wireless Networks)

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13 pages, 4162 KiB

Open AccessArticle

Multichannel Discriminative Detection of Explosive Vapors with an Array of Nanofibrous Membranes Loaded with Quantum Dots

by Zhaofeng Wu^1,2

, Haiming Duan¹, Zhijun Li^1,*, Jixi Guo², Furu Zhong², Yali Cao^2,* and Dianzeng Jia^2,*

¹ School of Physics Science and Technology, Xinjiang University, Urumqi 830046, China

² Key Laboratory of Energy Materials Chemistry, Ministry of Education, Key Laboratory of Advanced Functional Materials, Xinjiang University, Urumqi 830046, China

Sensors 2017, 17(11), 2676; https://doi.org/10.3390/s17112676 - 20 Nov 2017

Cited by 12 | Viewed by 5394

Abstract

The multichannel fluorescent sensor array based on nanofibrous membranes loaded with ZnS quantum dots (QDs) was created and demonstrated for the discriminative detection of explosives. The synergistic effect of the high surface-to-volume ratio of QDs, the good permeability of nanofibrous membranes and the [...] Read more.

The multichannel fluorescent sensor array based on nanofibrous membranes loaded with ZnS quantum dots (QDs) was created and demonstrated for the discriminative detection of explosives. The synergistic effect of the high surface-to-volume ratio of QDs, the good permeability of nanofibrous membranes and the differential response introduced by surface ligands was played by constructing the sensing array using nanofibrous membranes loaded with ZnS QDs featuring several surface ligands. Interestingly, although the fluorescence quenching of the nanofibrous membranes is not linearly related to the exposure time, the fingerprint of each explosive at different times is very similar in shape, and the fingerprints of the three explosives show different shapes. Three saturated vapors of nitroaromatic explosives could be reliably detected and discriminated by the array at room temperature. This work is the first step toward devising a monitoring system for explosives in the field of public security and defense. It could, for example, be coupled with the technology of image recognition and large data analysis for a rapid diagnostic test of explosives. This work further highlights the power of differential, multichannel arrays for the rapid and discriminative detection of a wide range of chemicals. Full article

(This article belongs to the Special Issue Fluorescent Probes and Sensors)

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12 pages, 6291 KiB

Open AccessArticle

Stretchable, Highly Durable Ternary Nanocomposite Strain Sensor for Structural Health Monitoring of Flexible Aircraft

by Feng Yin^1,2, Dong Ye^1,2, Chen Zhu^1,2, Lei Qiu³ and YongAn Huang^1,2,*

¹ State Key Lab of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China

² Flexible Electronics Research Center, Huazhong University of Science and Technology, Wuhan 430074, China

³ Research Center of Structural Health Monitoring and Prognosis, State Key Lab of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China

Sensors 2017, 17(11), 2677; https://doi.org/10.3390/s17112677 - 20 Nov 2017

Cited by 106 | Viewed by 9242

Abstract

Harmonious developments of electrical and mechanical performances are crucial for stretchable sensors in structural health monitoring (SHM) of flexible aircraft such as aerostats and morphing aircrafts. In this study, we prepared a highly durable ternary conductive nanocomposite made of polydimethylsiloxane (PDMS), carbon black [...] Read more.

Harmonious developments of electrical and mechanical performances are crucial for stretchable sensors in structural health monitoring (SHM) of flexible aircraft such as aerostats and morphing aircrafts. In this study, we prepared a highly durable ternary conductive nanocomposite made of polydimethylsiloxane (PDMS), carbon black (CB) and multi-walled carbon nanotubes (MWCNTs) to fabricate stretchable strain sensors. The nanocomposite has excellent electrical and mechanical properties by intensively optimizing the weight percentage of conducting fillers as well as the ratio of PDMS pre-polymer and curing agent. It was found that the nanocomposite with homogeneous hybrid filler of 1.75 wt % CB and 3 wt % MWCNTs exhibits a highly strain sensitive characteristics of good linearity, high gauge factor (GF ~ 12.25) and excellent durability over 10⁵ stretching-releasing cycles under a tensile strain up to 25% when the PDMS was prepared at the ratio of 12.5:1. A strain measurement of crack detection for the aerostats surface was also employed, demonstrating a great potential of such ternary nanocomposite used as stretchable strain sensor in SHM. Full article

(This article belongs to the Special Issue Sensor Technologies for Health Monitoring of Composite Structures)

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15 pages, 3289 KiB

Open AccessArticle

Constructing an Indoor Floor Plan Using Crowdsourcing Based on Magnetic Fingerprinting

by Haiyong Luo^1,*

, Fang Zhao², Mengling Jiang², Hao Ma² and Yuexia Zhang³

¹ Beijing Key Laboratory of Mobile Computing and Pervasive Device, Institute of Computing Technology Chinese Academy of Sciences, Beijing 100190, China

² School of Software Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China

³ School of Information and Telecommunication Engineering, Beijing Information Science and Technology University, Beijing 100101, China

Sensors 2017, 17(11), 2678; https://doi.org/10.3390/s17112678 - 20 Nov 2017

Cited by 50 | Viewed by 6952

Abstract

A large number of indoor positioning systems have recently been developed to cater for various location-based services. Indoor maps are a prerequisite of such indoor positioning systems; however, indoor maps are currently non-existent for most indoor environments. Construction of an indoor map by [...] Read more.

A large number of indoor positioning systems have recently been developed to cater for various location-based services. Indoor maps are a prerequisite of such indoor positioning systems; however, indoor maps are currently non-existent for most indoor environments. Construction of an indoor map by external experts excludes quick deployment and prevents widespread utilization of indoor localization systems. Here, we propose an algorithm for the automatic construction of an indoor floor plan, together with a magnetic fingerprint map of unmapped buildings using crowdsourced smartphone data. For floor plan construction, our system combines the use of dead reckoning technology, an observation model with geomagnetic signals, and trajectory fusion based on an affinity propagation algorithm. To obtain the indoor paths, the magnetic trajectory data obtained through crowdsourcing were first clustered using dynamic time warping similarity criteria. The trajectories were inferred from odometry tracing, and those belonging to the same cluster in the magnetic trajectory domain were then fused. Fusing these data effectively eliminates the inherent tracking errors originating from noisy sensors; as a result, we obtained highly accurate indoor paths. One advantage of our system is that no additional hardware such as a laser rangefinder or wheel encoder is required. Experimental results demonstrate that our proposed algorithm successfully constructs indoor floor plans with 0.48 m accuracy, which could benefit location-based services which lack indoor maps. Full article

(This article belongs to the Special Issue Sensors and Sensing in Indoor Localization, Tracking, Navigation and Activity Monitoring)

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16 pages, 4910 KiB

Open AccessArticle

Nondestructive Evaluation of Carbon Fiber Bicycle Frames Using Infrared Thermography

by Rubén Usamentiaga^1,*

, Clemente Ibarra-Castanedo^2,3

, Matthieu Klein³

, Xavier Maldague²

, Jeroen Peeters⁴

and Alvaro Sanchez-Beato⁵

¹ Department of Computer Science and Engineering, University of Oviedo, 33204 Gijón, Asturias, Spain

² Computer Vision and Systems Laboratory, Laval University, Quebec City, QC G1V 0A6, Canada

³ Visiooimage Inc., Infrared Thermography Testing Systems, 2604, Rue Lapointe, Quebec City, QC G1W 1A8, Canada

⁴ Op3Mech Research Group, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium

⁵ Actia Digital Ventures SRLU (THEBIKESPLACE.COM), 28413 Madrid, Spain

Sensors 2017, 17(11), 2679; https://doi.org/10.3390/s17112679 - 20 Nov 2017

Cited by 17 | Viewed by 9529

Abstract

Bicycle frames made of carbon fibre are extremely popular for high-performance cycling due to the stiffness-to-weight ratio, which enables greater power transfer. However, products manufactured using carbon fibre are sensitive to impact damage. Therefore, intelligent nondestructive evaluation is a required step to prevent [...] Read more.

Bicycle frames made of carbon fibre are extremely popular for high-performance cycling due to the stiffness-to-weight ratio, which enables greater power transfer. However, products manufactured using carbon fibre are sensitive to impact damage. Therefore, intelligent nondestructive evaluation is a required step to prevent failures and ensure a secure usage of the bicycle. This work proposes an inspection method based on active thermography, a proven technique successfully applied to other materials. Different configurations for the inspection are tested, including power and heating time. Moreover, experiments are applied to a real bicycle frame with generated impact damage of different energies. Tests show excellent results, detecting the generated damage during the inspection. When the results are combined with advanced image post-processing methods, the SNR is greatly increased, and the size and localization of the defects are clearly visible in the images. Full article

(This article belongs to the Special Issue Intelligent Sensing Technologies for Nondestructive Evaluation)

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28 pages, 1890 KiB

Open AccessArticle

A Lightweight Anonymous Authentication Protocol with Perfect Forward Secrecy for Wireless Sensor Networks

by Ling Xiong¹, Daiyuan Peng¹, Tu Peng², Hongbin Liang^3,* and Zhicai Liu⁴

¹ School of Information Science and Technology, Southwest Jiaotong University, Chengdu 611756, China

² School of Software, Beijing Institute of Technology, Beijing 100081, China

³ School of Transportation and Logistics, Southwest Jiaotong University, Chengdu 611756, China

⁴ School of Computer and Software Engineering, Xihua University, Chengdu 610039, China

Sensors 2017, 17(11), 2681; https://doi.org/10.3390/s17112681 - 21 Nov 2017

Cited by 51 | Viewed by 6637

Abstract

Due to their frequent use in unattended and hostile deployment environments, the security in wireless sensor networks (WSNs) has attracted much interest in the past two decades. However, it remains a challenge to design a lightweight authentication protocol for WSNs because the designers [...] Read more.

Due to their frequent use in unattended and hostile deployment environments, the security in wireless sensor networks (WSNs) has attracted much interest in the past two decades. However, it remains a challenge to design a lightweight authentication protocol for WSNs because the designers are confronted with a series of desirable security requirements, e.g., user anonymity, perfect forward secrecy, resistance to de-synchronization attack. Recently, the authors presented two authentication schemes that attempt to provide user anonymity and to resist various known attacks. Unfortunately, in this work we shall show that user anonymity of the two schemes is achieved at the price of an impractical search operation—the gateway node may search for every possible value. Besides this defect, they are also prone to smart card loss attacks and have no provision for perfect forward secrecy. As our main contribution, a lightweight anonymous authentication scheme with perfect forward secrecy is designed, and what we believe the most interesting feature is that user anonymity, perfect forward secrecy, and resistance to de-synchronization attack can be achieved at the same time. As far as we know, it is extremely difficult to meet these security features simultaneously only using the lightweight operations, such as symmetric encryption/decryption and hash functions. Full article

(This article belongs to the Special Issue Security, Trust and Privacy for Sensor Networks)

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14 pages, 2649 KiB

Open AccessArticle

Development and Validation of an On-Line Water Toxicity Sensor with Immobilized Luminescent Bacteria for On-Line Surface Water Monitoring

by Marjolijn Woutersen^1,*,†, Bram Van der Gaag^†, Afua Abrafi Boakye^2,†, Jan Mink³

, Robert S. Marks^4,5,6, Arco J. Wagenvoort⁷, Henk A. M. Ketelaars⁸, Bram Brouwer^9,10 and Minne B. Heringa^1,†

¹ National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands

² PAREXEL International, The Quays, 101-105 Oxford Rd, Uxbridge UB8 1LZ, UK

³ VTEC Lasers & Sensors, Kastanjelaan 400, 5616 LZ Eindhoven, The Netherlands

⁴ Department of Biotechnology Engineering, Faculty of Engineering Science, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel

⁵ National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel

⁶ The Ilse Katz Center for Meso and Nanoscale Science and Technology, Ben-Gurion University of the 6egev, Beer-Sheva 84105, Israel

⁷ AqWa ecologisch advies, Voorstad 45, 4461 KL Goes, The Netherlands

⁸ Evides Water Company, Schaardijk 150, 3063 NH Rotterdam, The Netherlands

⁹ Vrije Universiteit Faculty of Earth & Life Sciences, Department of Animal Ecology, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands

¹⁰ BioDectection Systems, Science Park 406, 1089 XH Amsterdam, The Netherlands

^† Affiliation at the time of the study: KWR Watercycle Research Institute, Groningenhaven 7, 3433 PE Nieuwegein, The Netherlands

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Sensors 2017, 17(11), 2682; https://doi.org/10.3390/s17112682 - 22 Nov 2017

Cited by 15 | Viewed by 6370

Abstract

Surface water used for drinking water production is frequently monitored in The Netherlands using whole organism biomonitors, with for example Daphnia magna or Dreissena mussels, which respond to changes in the water quality. However, not all human-relevant toxic compounds can be detected by [...] Read more.

Surface water used for drinking water production is frequently monitored in The Netherlands using whole organism biomonitors, with for example Daphnia magna or Dreissena mussels, which respond to changes in the water quality. However, not all human-relevant toxic compounds can be detected by these biomonitors. Therefore, a new on-line biosensor has been developed, containing immobilized genetically modified bacteria, which respond to genotoxicity in the water by emitting luminescence. The performance of this sensor was tested under laboratory conditions, as well as under field conditions at a monitoring station along the river Meuse in The Netherlands. The sensor was robust and easy to clean, with inert materials, temperature control and nutrient feed for the reporter organisms. The bacteria were immobilized in sol-gel on either an optical fiber or a glass slide and then continuously exposed to water. Since the glass slide was more sensitive and robust, only this setup was used in the field. The sensor responded to spikes of genotoxic compounds in the water with a minimal detectable concentration of 0.01 mg/L mitomycin C in the laboratory and 0.1 mg/L mitomycin C in the field. With further optimization, which should include a reduction in daily maintenance, the sensor has the potential to become a useful addition to the currently available biomonitors. Full article

(This article belongs to the Special Issue Sensors for Toxic and Pathogen Detection)

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26 pages, 9450 KiB

Open AccessArticle

First Spaceborne SAR-GMTI Experimental Results for the Chinese Gaofen-3 Dual-Channel SAR Sensor

by Chenghao Wang¹, Guisheng Liao¹ and Qingjun Zhang^2,*

¹ National Key Laboratory of Radar Signal Processing, Xidian University, Shaanxi 710071, China

² Beijing Institute of Spacecraft System Engineering, China Academy of Space Technology, Beijing 100094, China

Sensors 2017, 17(11), 2683; https://doi.org/10.3390/s17112683 - 21 Nov 2017

Cited by 33 | Viewed by 9730

Abstract

In spaceborne synthetic aperture radar (SAR) sensors, it is a challenging task to detect ground slow-moving targets against strong clutter background with limited spatial channels and restricted pulse repetition frequency (PRF). In this paper, we evaluate the image-based dual-channel SAR-ground moving target indication [...] Read more.

In spaceborne synthetic aperture radar (SAR) sensors, it is a challenging task to detect ground slow-moving targets against strong clutter background with limited spatial channels and restricted pulse repetition frequency (PRF). In this paper, we evaluate the image-based dual-channel SAR-ground moving target indication (SAR-GMTI) workflow for the Gaofen-3 SAR sensor and analyze the impact of strong azimuth ambiguities on GMTI when the displaced phase center antenna (DPCA) condition is not fully satisfied, which has not been demonstrated yet. An effective sliding window design technique based on system parameters analysis is proposed to deal with azimuth ambiguities and reduce false alarm. In the SAR-GMTI experiments, co-registration, clutter suppression, constant false alarm rate (CFAR) detector, vector velocity estimation and moving target relocation are analyzed and discussed thoroughly. With the real measured data of the Gaofen-3 dual-channel SAR sensor, the GMTI capability of this sensor is demonstrated and the effectiveness of the proposed method is verified. Full article

(This article belongs to the Special Issue First Experiences with Chinese Gaofen-3 SAR Sensor)

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8 pages, 1402 KiB

Open AccessArticle

A Novel Detection Method of Human Serum Albumin Based on the Poly(Thymine)-Templated Copper Nanoparticles

by Mingjian Chen^†, Xinying Xiang^†, Kefeng Wu, Hailun He, Hanchun Chen and Changbei Ma^*

¹ School of Life Sciences, Central South University, Changsha 410013, China

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2684; https://doi.org/10.3390/s17112684 - 21 Nov 2017

Cited by 31 | Viewed by 7570

Abstract

In this work, we developed a facile fluorescence method for quantitative detection of human serum albumin (HSA) based on the inhibition of poly(thymine) (poly T)-templated copper nanoparticles (CuNPs) in the presence of HSA. Under normal circumstances, poly T-templated CuNPs can display strong fluorescence [...] Read more.

In this work, we developed a facile fluorescence method for quantitative detection of human serum albumin (HSA) based on the inhibition of poly(thymine) (poly T)-templated copper nanoparticles (CuNPs) in the presence of HSA. Under normal circumstances, poly T-templated CuNPs can display strong fluorescence with excitation/emission peaks at 340/610 nm. However, in the presence of HSA, it will absorb cupric ion, which will prevent the formation of CuNPs. As a result, the fluorescence intensity will become obviously lower in the presence of HSA. The analyte HSA concentration had a proportional linear relationship with the fluorescence intensity of CuNPs. The detection limit for HSA was 8.2 × 10⁻⁸ mol·L⁻¹. Furthermore, it was also successfully employed to determine HSA in biological samples. Thus, this method has potential applications in point-of-care medical diagnosis and biomedical research. Full article

(This article belongs to the Special Issue Biosensors for Cancer Biomarkers)

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13 pages, 1758 KiB

Open AccessArticle

Micro-Droplet Detection Method for Measuring the Concentration of Alkaline Phosphatase-Labeled Nanoparticles in Fluorescence Microscopy

by Rufeng Li¹, Yibei Wang¹, Hong Xu¹, Baowei Fei² and Binjie Qin^1,*

¹ School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

² Emory University School of Medicine, Georgia Institute of Technology, Atlanta, GA 30329 USA

Sensors 2017, 17(11), 2685; https://doi.org/10.3390/s17112685 - 21 Nov 2017

Cited by 5 | Viewed by 6550

Abstract

This paper developed and evaluated a quantitative image analysis method to measure the concentration of the nanoparticles on which alkaline phosphatase (AP) was immobilized. These AP-labeled nanoparticles are widely used as signal markers for tagging biomolecules at nanometer and sub-nanometer scales. The AP-labeled [...] Read more.

This paper developed and evaluated a quantitative image analysis method to measure the concentration of the nanoparticles on which alkaline phosphatase (AP) was immobilized. These AP-labeled nanoparticles are widely used as signal markers for tagging biomolecules at nanometer and sub-nanometer scales. The AP-labeled nanoparticle concentration measurement can then be directly used to quantitatively analyze the biomolecular concentration. Micro-droplets are mono-dispersed micro-reactors that can be used to encapsulate and detect AP-labeled nanoparticles. Micro-droplets include both empty micro-droplets and fluorescent micro-droplets, while fluorescent micro-droplets are generated from the fluorescence reaction between the APs adhering to a single nanoparticle and corresponding fluorogenic substrates within droplets. By detecting micro-droplets and calculating the proportion of fluorescent micro-droplets to the overall micro-droplets, we can calculate the AP-labeled nanoparticle concentration. The proposed micro-droplet detection method includes the following steps: (1) Gaussian filtering to remove the noise of overall fluorescent targets, (2) a contrast-limited, adaptive histogram equalization processing to enhance the contrast of weakly luminescent micro-droplets, (3) an red maximizing inter-class variance thresholding method (OTSU) to segment the enhanced image for getting the binary map of the overall micro-droplets, (4) a circular Hough transform (CHT) method to detect overall micro-droplets and (5) an intensity-mean-based thresholding segmentation method to extract the fluorescent micro-droplets. The experimental results of fluorescent micro-droplet images show that the average accuracy of our micro-droplet detection method is 0.9586; the average true positive rate is 0.9502; and the average false positive rate is 0.0073. The detection method can be successfully applied to measure AP-labeled nanoparticle concentration in fluorescence microscopy. Full article

(This article belongs to the Special Issue Optical Methods in Sensing and Imaging for Medical and Biological Applications)

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12 pages, 16425 KiB

Open AccessArticle

A Portable Stiffness Measurement System

by Onejae Sul¹, Eunsuk Choi²

and Seung-Beck Lee^1,2,*

¹ Institute of Nano Science and Technology, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea

² Department of Electronic Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea

Sensors 2017, 17(11), 2686; https://doi.org/10.3390/s17112686 - 21 Nov 2017

Cited by 8 | Viewed by 6508

Abstract

A new stiffness measurement method is proposed that utilizes the lateral deformation profile of an object under indentation. The system consists of a force measurement module between a pair of equidistant touch sensing modules. Unique feature of the method is that by adjusting [...] Read more.

A new stiffness measurement method is proposed that utilizes the lateral deformation profile of an object under indentation. The system consists of a force measurement module between a pair of equidistant touch sensing modules. Unique feature of the method is that by adjusting the touch module separation, indenter protrusion, and spring constant of the force sensing module, one can choose a desired sensing range for the force module. This feature helps to enhance the stiffness differentiation between objects of similar hardness and avoids measurement saturation. We devised a portable measurement system based on the method, and tested its performance with several materials including polymer foams and human skin. Full article

(This article belongs to the Special Issue Tactile Sensors and Sensing)

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18 pages, 4084 KiB

Open AccessArticle

Study and Validation of Eavesdropping Scenarios over a Visible Light Communication Channel

by Ignacio Marin-Garcia^1,2,*,†

, Victor Guerra^2,†

and Rafael Perez-Jimenez^2,†

¹ Facultad de Ingenieria en Electricidad y Computacion, Escuela Superior Politecnica del Litoral (ESPOL), P.O. Box 09-01-5863 Guayaquil, Ecuador

² Instituto para el Desarrollo de las Telecomunicaciones (IDeTIC), Universidad de las Palmas de Gran Canaria, 35001 Las Palmas de Gran Canaria, Spain

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2687; https://doi.org/10.3390/s17112687 - 21 Nov 2017

Cited by 23 | Viewed by 6396

Abstract

The security and privacy provided by Visible Light Communication (VLC) technologies is an area that has been slightly addressed due to the misconception that, since light does not go through solid objects like walls, VLC-based communications cannot be eavesdropped on by outside observers. [...] Read more.

The security and privacy provided by Visible Light Communication (VLC) technologies is an area that has been slightly addressed due to the misconception that, since light does not go through solid objects like walls, VLC-based communications cannot be eavesdropped on by outside observers. As an upcoming technology, VLC is expected to be used in multiple environments were, due to radio frequency RF overuse or limitations, RF solutions cannot or should not be employed. In this work, we study the eavesdropping characteristics of a VLC-based communication. To evaluate these concerns, a two-step process was followed. First, several simulations of a standardly used scenario were run. Later on, experimental tests were performed. Following those tests, the results of the simulations and the experimental tests were analyzed. The results of these simulations and tests seemed to indicate that VLC channels can be eavesdropped on without considerable difficulties. Furthermore, the results showed that sniffing attacks could be performed from areas outside the expected coverage of the VLC infrastructure. Finally, the use of the simulation such as the one implemented in this work to recognize places from which sniffing is possible helps determine the risk for eavesdropping that our VLC-based network has. Full article

(This article belongs to the Special Issue Visible Light Communication Networks)

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15 pages, 1667 KiB

Open AccessArticle

by Alejandra García-Hernández^1,†, Carlos E. Galván-Tejada^1,*,†

, Jorge I. Galván-Tejada¹, José M. Celaya-Padilla²

, Hamurabi Gamboa-Rosales¹

, Perla Velasco-Elizondo¹ and Rogelio Cárdenas-Vargas³

¹ Academic Unit of Electrical Engineering, Autonomous University of Zacatecas, Jardín Juarez 147, Centro, Zacatecas 98000, Zacatecas, Mexico

² CONACyT—Academic Unit of Electrical Engineering, Autonomous University of Zacatecas , Jardín Juarez 147, Centro, Zacatecas 98000, Zacatecas, Mexico

³ Chemical Engineering Program, Autonomous University of Zacatecas, Ciudad Universitaria Siglo XXI, Carretera Zacatecas-Guadalajara Km. 6, Ejido La Escondida, Zacatecas 98160, Zacatecas, Mexico

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2688; https://doi.org/10.3390/s17112688 - 21 Nov 2017

Cited by 6 | Viewed by 4923

Abstract

Human Activity Recognition (HAR) is one of the main subjects of study in the areas of computer vision and machine learning due to the great benefits that can be achieved. Examples of the study areas are: health prevention, security and surveillance, automotive research, [...] Read more.

Human Activity Recognition (HAR) is one of the main subjects of study in the areas of computer vision and machine learning due to the great benefits that can be achieved. Examples of the study areas are: health prevention, security and surveillance, automotive research, and many others. The proposed approaches are carried out using machine learning techniques and present good results. However, it is difficult to observe how the descriptors of human activities are grouped. In order to obtain a better understanding of the the behavior of descriptors, it is important to improve the abilities to recognize the human activities. This paper proposes a novel approach for the HAR based on acoustic data and similarity networks. In this approach, we were able to characterize the sound of the activities and identify those activities looking for similarity in the sound pattern. We evaluated the similarity of the sounds considering mainly two features: the sound location and the materials that were used. As a result, the materials are a good reference classifying the human activities compared with the location. Full article

(This article belongs to the Section Sensor Networks)

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22 pages, 1143 KiB

Open AccessArticle

Target Tracking with Sensor Navigation Using Coupled RSS and AoA Measurements

by Slavisa Tomic^1,*, Marko Beko^2,3

, Rui Dinis^4,5 and João Pedro Gomes¹

¹ ISR/IST, LARSyS, Universidade de Lisboa, 1049-001 Lisbon, Portugal

² CICANT-CIC.DIGITAL, Universidade Lusófona de Humanidades e Tecnologias, Campo Grande 376, 1749-024 Lisboa, Portugal

³ CTS/UNINOVA, Campus da FCT/UNL, Monte de Caparica, 2829-516 Caparica, Portugal

⁴ Instituto de Telecomunicações, Av. Rovisco Pais 1, Torre Norte, piso 10, 1049-001 Lisboa, Portugal

⁵ Dep.o de Eng.a Electrotécnica, FCT/UNL, 2829-516 Caparica, Portugal

Sensors 2017, 17(11), 2690; https://doi.org/10.3390/s17112690 - 21 Nov 2017

Cited by 17 | Viewed by 5033

Abstract

This work addresses the problem of tracking a signal-emitting mobile target in wireless sensor networks (WSNs) with navigated mobile sensors. The sensors are properly equipped to acquire received signal strength (RSS) and angle of arrival (AoA) measurements from the received signal, while the [...] Read more.

This work addresses the problem of tracking a signal-emitting mobile target in wireless sensor networks (WSNs) with navigated mobile sensors. The sensors are properly equipped to acquire received signal strength (RSS) and angle of arrival (AoA) measurements from the received signal, while the target transmit power is assumed not known. We start by showing how to linearize the highly non-linear measurement model. Then, by employing a Bayesian approach, we combine the linearized observation model with prior knowledge extracted from the state transition model. Based on the maximum a posteriori (MAP) principle and the Kalman filtering (KF) framework, we propose new MAP and KF algorithms, respectively. We also propose a simple and efficient mobile sensor navigation procedure, which allows us to further enhance the estimation accuracy of our algorithms with a reduced number of sensors. Model flaws, which result in imperfect knowledge about the path loss exponent (PLE) and the true mobile sensors’ locations, are taken into consideration. We have carried out an extensive simulation study, and our results confirm the superiority of the proposed algorithms, as well as the effectiveness of the proposed navigation routine. Full article

(This article belongs to the Section Physical Sensors)

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13 pages, 797 KiB

Open AccessArticle

Dielectrophoretic Separation of Live and Dead Monocytes Using 3D Carbon-Electrodes

by Yagmur Yildizhan¹, Nurdan Erdem¹

, Monsur Islam²

, Rodrigo Martinez-Duarte²

and Meltem Elitas^1,*

¹ Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul 34956, Turkey

² Mechanical Engineering Department, Clemson University, Clemson, SC 29631, USA

Sensors 2017, 17(11), 2691; https://doi.org/10.3390/s17112691 - 22 Nov 2017

Cited by 64 | Viewed by 7749

Abstract

Blood has been the most reliable body fluid commonly used for the diagnosis of diseases. Although there have been promising investigations for the development of novel lab-on-a-chip devices to utilize other body fluids such as urine and sweat samples in diagnosis, their stability [...] Read more.

Blood has been the most reliable body fluid commonly used for the diagnosis of diseases. Although there have been promising investigations for the development of novel lab-on-a-chip devices to utilize other body fluids such as urine and sweat samples in diagnosis, their stability remains a problem that limits the reliability and accuracy of readouts. Hence, accurate and quantitative separation and characterization of blood cells are still crucial. The first step in achieving high-resolution characteristics for specific cell subpopulations from the whole blood is the isolation of pure cell populations from a mixture of cell suspensions. Second, live cells need to be purified from dead cells; otherwise, dead cells might introduce biases in the measurements. In addition, the separation and characterization methods being used must preserve the genetic and phenotypic properties of the cells. Among the characterization and separation approaches, dielectrophoresis (DEP) is one of the oldest and most efficient label-free quantification methods, which directly purifies and characterizes cells using their intrinsic, physical properties. In this study, we present the dielectrophoretic separation and characterization of live and dead monocytes using 3D carbon-electrodes. Our approach successfully removed the dead monocytes while preserving the viability of the live monocytes. Therefore, when blood analyses and disease diagnosis are performed with enriched, live monocyte populations, this approach will reduce the dead-cell contamination risk and achieve more reliable and accurate test results. Full article

(This article belongs to the Special Issue Bio-MEMS for Precision Medicine)

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16 pages, 6364 KiB

Open AccessArticle

An Orientation Sensor-Based Head Tracking System for Driver Behaviour Monitoring

by Yifan Zhao^1,*

, Lorenz Görne¹, Iek-Man Yuen¹, Dongpu Cao¹, Mark Sullman¹, Daniel Auger¹

, Chen Lv¹, Huaji Wang¹, Rebecca Matthias², Lee Skrypchuk² and Alexandros Mouzakitis²

¹ School of Aerospace, Transport and Manufacturing, Cranfield University, Cranfield MK43 0AL, UK

² Jaguar Land Rover Limited, University Road, University of Warwick, Coventry CV4 7AL, UK

Sensors 2017, 17(11), 2692; https://doi.org/10.3390/s17112692 - 22 Nov 2017

Cited by 26 | Viewed by 10862

Abstract

Although at present legislation does not allow drivers in a Level 3 autonomous vehicle to engage in a secondary task, there may become a time when it does. Monitoring the behaviour of drivers engaging in various non-driving activities (NDAs) is crucial to decide [...] Read more.

Although at present legislation does not allow drivers in a Level 3 autonomous vehicle to engage in a secondary task, there may become a time when it does. Monitoring the behaviour of drivers engaging in various non-driving activities (NDAs) is crucial to decide how well the driver will be able to take over control of the vehicle. One limitation of the commonly used face-based head tracking system, using cameras, is that sufficient features of the face must be visible, which limits the detectable angle of head movement and thereby measurable NDAs, unless multiple cameras are used. This paper proposes a novel orientation sensor based head tracking system that includes twin devices, one of which measures the movement of the vehicle while the other measures the absolute movement of the head. Measurement error in the shaking and nodding axes were less than 0.4°, while error in the rolling axis was less than 2°. Comparison with a camera-based system, through in-house tests and on-road tests, showed that the main advantage of the proposed system is the ability to detect angles larger than 20° in the shaking and nodding axes. Finally, a case study demonstrated that the measurement of the shaking and nodding angles, produced from the proposed system, can effectively characterise the drivers’ behaviour while engaged in the NDAs of chatting to a passenger and playing on a smartphone. Full article

(This article belongs to the Special Issue Sensors for Transportation)

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14 pages, 1782 KiB

Open AccessArticle

Comparison of Benchtop Fourier-Transform (FT) and Portable Grating Scanning Spectrometers for Determination of Total Soluble Solid Contents in Single Grape Berry (Vitis vinifera L.) and Calibration Transfer

by Hui Xiao, Ke Sun, Ye Sun, Kangli Wei, Kang Tu and Leiqing Pan^*

College of Food Science and Technology, Nanjing Agriculture University, Nanjing 21009, China

Sensors 2017, 17(11), 2693; https://doi.org/10.3390/s17112693 - 22 Nov 2017

Cited by 28 | Viewed by 5314

Abstract

Near-infrared (NIR) spectroscopy was applied for the determination of total soluble solid contents (SSC) of single Ruby Seedless grape berries using both benchtop Fourier transform (VECTOR 22/N) and portable grating scanning (SupNIR-1500) spectrometers in this study. The results showed that the best SSC [...] Read more.

Near-infrared (NIR) spectroscopy was applied for the determination of total soluble solid contents (SSC) of single Ruby Seedless grape berries using both benchtop Fourier transform (VECTOR 22/N) and portable grating scanning (SupNIR-1500) spectrometers in this study. The results showed that the best SSC prediction was obtained by VECTOR 22/N in the range of 12,000 to 4000 cm⁻¹ (833–2500 nm) for Ruby Seedless with determination coefficient of prediction (R_p²) of 0.918, root mean squares error of prediction (RMSEP) of 0.758% based on least squares support vector machine (LS-SVM). Calibration transfer was conducted on the same spectral range of two instruments (1000–1800 nm) based on the LS-SVM model. By conducting Kennard-Stone (KS) to divide sample sets, selecting the optimal number of standardization samples and applying Passing-Bablok regression to choose the optimal instrument as the master instrument, a modified calibration transfer method between two spectrometers was developed. When 45 samples were selected for the standardization set, the linear interpolation-piecewise direct standardization (linear interpolation-PDS) performed well for calibration transfer with R_p² of 0.857 and RMSEP of 1.099% in the spectral region of 1000–1800 nm. And it was proved that re-calculating the standardization samples into master model could improve the performance of calibration transfer in this study. This work indicated that NIR could be used as a rapid and non-destructive method for SSC prediction, and provided a feasibility to solve the transfer difficulty between totally different NIR spectrometers. Full article

(This article belongs to the Special Issue Signal and Information Processing in Chemical Sensing)

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15 pages, 2726 KiB

Open AccessArticle

A Collaboration-Oriented M2M Messaging Mechanism for the Collaborative Automation between Machines in Future Industrial Networks

by Zhaozong Meng

, Zhipeng Wu^*

and John Gray

School of Electrical and Electronic Engineering, University of Manchester, Oxford Road, Manchester M13 9PL, UK

Sensors 2017, 17(11), 2694; https://doi.org/10.3390/s17112694 - 22 Nov 2017

Cited by 24 | Viewed by 7783

Abstract

Machine-to-machine (M2M) communication is a key enabling technology for industrial internet of things (IIoT)-empowered industrial networks, where machines communicate with one another for collaborative automation and intelligent optimisation. This new industrial computing paradigm features high-quality connectivity, ubiquitous messaging, and interoperable interactions between machines. [...] Read more.

Machine-to-machine (M2M) communication is a key enabling technology for industrial internet of things (IIoT)-empowered industrial networks, where machines communicate with one another for collaborative automation and intelligent optimisation. This new industrial computing paradigm features high-quality connectivity, ubiquitous messaging, and interoperable interactions between machines. However, manufacturing IIoT applications have specificities that distinguish them from many other internet of things (IoT) scenarios in machine communications. By highlighting the key requirements and the major technical gaps of M2M in industrial applications, this article describes a collaboration-oriented M2M (CoM2M) messaging mechanism focusing on flexible connectivity and discovery, ubiquitous messaging, and semantic interoperability that are well suited for the production line-scale interoperability of manufacturing applications. The designs toward machine collaboration and data interoperability at both the communication and semantic level are presented. Then, the application scenarios of the presented methods are illustrated with a proof-of-concept implementation in the PicknPack food packaging line. Eventually, the advantages and some potential issues are discussed based on the PicknPack practice. Full article

(This article belongs to the Collection Smart Industrial Wireless Sensor Networks)

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30 pages, 13720 KiB

Open AccessArticle

A Novel 3D Pedestrian Navigation Method for a Multiple Sensors-Based Foot-Mounted Inertial System

by Wei Yang, Chundi Xiu^*, Jianmin Zhang and Dongkai Yang

School of Electronic and Information Engineering, Beihang University, Beijing 100083, China

Sensors 2017, 17(11), 2695; https://doi.org/10.3390/s17112695 - 22 Nov 2017

Cited by 37 | Viewed by 6139

Abstract

In this paper, we present a novel method for 3D pedestrian navigation of foot-mounted inertial systems by integrating a MEMS-IMU, barometer, and permanent magnet. Zero-velocity update (ZUPT) is a well-known algorithm to eliminate the accumulated error of foot-mounted inertial systems. However, the ZUPT [...] Read more.

In this paper, we present a novel method for 3D pedestrian navigation of foot-mounted inertial systems by integrating a MEMS-IMU, barometer, and permanent magnet. Zero-velocity update (ZUPT) is a well-known algorithm to eliminate the accumulated error of foot-mounted inertial systems. However, the ZUPT stance phase detector using acceleration and angular rate is threshold-based, which may cause incorrect stance phase estimation in the running gait pattern. A permanent magnet-based ZUPT detector is introduced to solve this problem. Peaks extracted from the magnetic field strength waveform are mid-stances of stance phases. A model of peak-peak information and stance phase duration is developed to have a quantitative calculation method of stance phase duration in different movement patterns. Height estimation using barometer is susceptible to the environment. A height difference information aided barometer (HDIB) algorithm integrating MEMS-IMU and barometer is raised to have a better height estimation. The first stage of HDIB is to distinguish level ground/upstairs/downstairs and the second stage is to calculate height using reference atmospheric pressure obtained from the first stage. At last, a ZUPT-based adaptive average window length algorithm (ZUPT-AAWL) is proposed to calculate the true total travelled distance to have a more accurate percentage error (TTDE). This proposed method is verified via multiple experiments. Numerical results show that TTDE ranges from 0.32% to 1.04% in both walking and running gait patterns, and the height estimation error is from 0 m to 2.35 m. Full article

(This article belongs to the Section Physical Sensors)

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11 pages, 3732 KiB

Open AccessArticle

An Optical Interferometric Triaxial Displacement Sensor for Structural Health Monitoring: Characterization of Sliding and Debonding for a Delamination Process

by Chen Zhu^1,†

, Yizheng Chen^1,†, Yiyang Zhuang¹, Yang Du¹, Rex E. Gerald II², Yan Tang¹ and Jie Huang^1,*

¹ Department of Electrical and Computer Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA

² American Inventor Institute, Willow Spring, IL 60480, USA

^† The first two authors should be regarded as joint first authors.

Sensors 2017, 17(11), 2696; https://doi.org/10.3390/s17112696 - 22 Nov 2017

Cited by 28 | Viewed by 5395

Abstract

This paper presents an extrinsic Fabry–Perot interferometer-based optical fiber sensor (EFPI) for measuring three-dimensional (3D) displacements, including interfacial sliding and debonding during delamination. The idea employs three spatially arranged EFPIs as the sensing elements. In our sensor, the three EFPIs are formed by [...] Read more.

This paper presents an extrinsic Fabry–Perot interferometer-based optical fiber sensor (EFPI) for measuring three-dimensional (3D) displacements, including interfacial sliding and debonding during delamination. The idea employs three spatially arranged EFPIs as the sensing elements. In our sensor, the three EFPIs are formed by three endfaces of three optical fibers and their corresponding inclined mirrors. Two coincident roof-like metallic structures are used to support the three fibers and the three mirrors, respectively. Our sensor was calibrated and then used to monitor interfacial sliding and debonding between a long square brick of mortar and its support structure (i.e., a steel base plate) during the drying/curing process. This robust and easy-to-manufacture triaxial EFPI-based 3D displacement sensor has great potential in structural health monitoring, the construction industry, oil well monitoring, and geotechnology. Full article

(This article belongs to the Section Physical Sensors)

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18 pages, 1318 KiB

Open AccessArticle

Optimal Pricing and Power Allocation for Collaborative Jamming with Full Channel Knowledge in Wireless Sensor Networks

by Dae-Kyo Jeong¹

, Insook Kim² and Dongwoo Kim^2,*

¹ Department of Electronics and Communication Engineering, Hanyang University, Ansan 15588, Korea

² Division of Electrical Engineering, Hanyang University, Ansan 15588, Korea

Sensors 2017, 17(11), 2697; https://doi.org/10.3390/s17112697 - 22 Nov 2017

Cited by 4 | Viewed by 4608

Abstract

This paper presents a price-searching model in which a source node (Alice) seeks friendly jammers that prevent eavesdroppers (Eves) from snooping legitimate communications by generating interference or noise. Unlike existing models, the distributed jammers also have data to send to their respective destinations [...] Read more.

This paper presents a price-searching model in which a source node (Alice) seeks friendly jammers that prevent eavesdroppers (Eves) from snooping legitimate communications by generating interference or noise. Unlike existing models, the distributed jammers also have data to send to their respective destinations and are allowed to access Alice’s channel if it can transmit sufficient jamming power, which is referred to as collaborative jamming in this paper. For the power used to deliver its own signal, the jammer should pay Alice. The price of the jammers’ signal power is set by Alice and provides a tradeoff between the signal and the jamming power. This paper presents, in closed-form, an optimal price that maximizes Alice’s benefit and the corresponding optimal power allocation from a jammers’ perspective by assuming that the network-wide channel knowledge is shared by Alice and jammers. For a multiple-jammer scenario where Alice hardly has the channel knowledge, this paper provides a distributed and interactive price-searching procedure that geometrically converges to an optimal price and shows that Alice by a greedy selection policy achieves certain diversity gain, which increases log-linearly as the number of (potential) jammers grows. Various numerical examples are presented to illustrate the behavior of the proposed model. Full article

(This article belongs to the Special Issue Sensor Networks for Collaborative and Secure Internet of Things)

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18 pages, 4889 KiB

Open AccessArticle

Markerless Knee Joint Position Measurement Using Depth Data during Stair Walking

by Ami Ogawa^1,*

, Akira Mita², Ayanori Yorozu³ and Masaki Takahashi²

¹ School of Science for Open and Environmental Systems, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan

² Department of System Design Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan

³ Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan

Sensors 2017, 17(11), 2698; https://doi.org/10.3390/s17112698 - 22 Nov 2017

Cited by 12 | Viewed by 8364

Abstract

Climbing and descending stairs are demanding daily activities, and the monitoring of them may reveal the presence of musculoskeletal diseases at an early stage. A markerless system is needed to monitor such stair walking activity without mentally or physically disturbing the subject. Microsoft [...] Read more.

Climbing and descending stairs are demanding daily activities, and the monitoring of them may reveal the presence of musculoskeletal diseases at an early stage. A markerless system is needed to monitor such stair walking activity without mentally or physically disturbing the subject. Microsoft Kinect v2 has been used for gait monitoring, as it provides a markerless skeleton tracking function. However, few studies have used this device for stair walking monitoring, and the accuracy of its skeleton tracking function during stair walking has not been evaluated. Moreover, skeleton tracking is not likely to be suitable for estimating body joints during stair walking, as the form of the body is different from what it is when it walks on level surfaces. In this study, a new method of estimating the 3D position of the knee joint was devised that uses the depth data of Kinect v2. The accuracy of this method was compared with that of the skeleton tracking function of Kinect v2 by simultaneously measuring subjects with a 3D motion capture system. The depth data method was found to be more accurate than skeleton tracking. The mean error of the 3D Euclidian distance of the depth data method was 43.2 ± 27.5 mm, while that of the skeleton tracking was 50.4 ± 23.9 mm. This method indicates the possibility of stair walking monitoring for the early discovery of musculoskeletal diseases. Full article

(This article belongs to the Section Physical Sensors)

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16 pages, 9872 KiB

Open AccessArticle

Pedestrian Detection with Semantic Regions of Interest

by Miao He^1,2,3,4,*

, Haibo Luo^1,2, Zheng Chang^1,2 and Bin Hui^1,2

¹ Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China

² Key Laboratory of Opto-Electronic Information Processing, Chinese Academy of Sciences, Shenyang 110016, China

³ The Key Lab of Image Understanding and Computer Vision, Shenyang 110016, China

⁴ University of Chinese Academy of Sciences, Beijing 110049, China

Sensors 2017, 17(11), 2699; https://doi.org/10.3390/s17112699 - 22 Nov 2017

Cited by 13 | Viewed by 6134

Abstract

For many pedestrian detectors, background vs. foreground errors heavily influence the detection quality. Our main contribution is to design semantic regions of interest that extract the foreground target roughly to reduce the background vs. foreground errors of detectors. First, we generate a pedestrian [...] Read more.

For many pedestrian detectors, background vs. foreground errors heavily influence the detection quality. Our main contribution is to design semantic regions of interest that extract the foreground target roughly to reduce the background vs. foreground errors of detectors. First, we generate a pedestrian heat map from the input image with a full convolutional neural network trained on the Caltech Pedestrian Dataset. Next, semantic regions of interest are extracted from the heat map by morphological image processing. Finally, the semantic regions of interest divide the whole image into foreground and background to assist the decision-making of detectors. We test our approach on the Caltech Pedestrian Detection Benchmark. With the help of our semantic regions of interest, the effects of the detectors have varying degrees of improvement. The best one exceeds the state-of-the-art. Full article

(This article belongs to the Section Physical Sensors)

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17 pages, 6341 KiB

Open AccessArticle

Low Computational-Cost Footprint Deformities Diagnosis Sensor through Angles, Dimensions Analysis and Image Processing Techniques

by J. Rodolfo Maestre-Rendon^1,2, Tomas A. Rivera-Roman¹

, Juan M. Sierra-Hernandez³, Ivan Cruz-Aceves⁴

, Luis M. Contreras-Medina⁵, Carlos Duarte-Galvan⁶

and Arturo A. Fernandez-Jaramillo^1,*

¹ Unidad Académica de Ingeniería Biomédica, Universidad Politécnica de Sinaloa, Carretera Municipal Libre Mazatlán Higueras km 3, Col. Genaro Estrada, Mazatlán Sin. 82199, Mexico

² Center for Biomedical Technology, Polythecnic University of Madrid, Campus Montegancedo, Pozuelo de Alarcón, Madrid 28223, Spain

³ Departamento de Ingeniería Electrónica, División de Ingenierías, Universidad de Guanajuato, Carretera Salamanca-Valle de Santiago km 3.5 + 1.8, Comunidad de Palo Blanco, Salamanca Gto. C.P. 36885, Mexico

⁴ CONACYT, Centro de Investigación en Matemáticas (CIMAT), A.C., Jalisco S/N, Col. Valenciana, Guanajuato Gto. 36000, Mexico

⁵ CA Ingeniería de Biosistemas, División de Investigación y Posgrado, Facultad de Ingeniería, Universidad Autónoma de Querétaro, Cerro de las campanas S/N, Santiago de Querétaro Qro. 76010, Mexico

⁶ Facultad de Ciencias Físico-Matemáticas, Universidad Autónoma de Sinaloa, Av. De las Américas y Blvd. Universitarios, Cd. Universitaria, Culiacán Sin. 80000, Mexico

Sensors 2017, 17(11), 2700; https://doi.org/10.3390/s17112700 - 22 Nov 2017

Cited by 14 | Viewed by 8017

Abstract

Manual measurements of foot anthropometry can lead to errors since this task involves the experience of the specialist who performs them, resulting in different subjective measures from the same footprint. Moreover, some of the diagnoses that are given to classify a footprint deformity [...] Read more.

Manual measurements of foot anthropometry can lead to errors since this task involves the experience of the specialist who performs them, resulting in different subjective measures from the same footprint. Moreover, some of the diagnoses that are given to classify a footprint deformity are based on a qualitative interpretation by the physician; there is no quantitative interpretation of the footprint. The importance of providing a correct and accurate diagnosis lies in the need to ensure that an appropriate treatment is provided for the improvement of the patient without risking his or her health. Therefore, this article presents a smart sensor that integrates the capture of the footprint, a low computational-cost analysis of the image and the interpretation of the results through a quantitative evaluation. The smart sensor implemented required the use of a camera (Logitech C920) connected to a Raspberry Pi 3, where a graphical interface was made for the capture and processing of the image, and it was adapted to a podoscope conventionally used by specialists such as orthopedist, physiotherapists and podiatrists. The footprint diagnosis smart sensor (FPDSS) has proven to be robust to different types of deformity, precise, sensitive and correlated in 0.99 with the measurements from the digitalized image of the ink mat. Full article

(This article belongs to the Special Issue Biomedical Sensors and Systems 2017)

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Review

Jump to: Research, Other

19 pages, 5045 KiB

Open AccessReview

Recent Progress in Optical Biosensors Based on Smartphone Platforms

by Zhaoxin Geng^1,*, Xiong Zhang^1,†, Zhiyuan Fan^2,†, Xiaoqing Lv², Yue Su² and Hongda Chen²

¹ School of Information Engineering, Minzu University of China, Beijing 100081, China

² State Key Laboratory for Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China

^† These authors contributed equally to this work.

Sensors 2017, 17(11), 2449; https://doi.org/10.3390/s17112449 - 25 Oct 2017

Cited by 138 | Viewed by 10699

Abstract

With a rapid improvement of smartphone hardware and software, especially complementary metal oxide semiconductor (CMOS) cameras, many optical biosensors based on smartphone platforms have been presented, which have pushed the development of the point-of-care testing (POCT). Imaging-based and spectrometry-based detection techniques have been [...] Read more.

With a rapid improvement of smartphone hardware and software, especially complementary metal oxide semiconductor (CMOS) cameras, many optical biosensors based on smartphone platforms have been presented, which have pushed the development of the point-of-care testing (POCT). Imaging-based and spectrometry-based detection techniques have been widely explored via different approaches. Combined with the smartphone, imaging-based and spectrometry-based methods are currently used to investigate a wide range of molecular properties in chemical and biological science for biosensing and diagnostics. Imaging techniques based on smartphone-based microscopes are utilized to capture microscale analysts, while spectrometry-based techniques are used to probe reactions or changes of molecules. Here, we critically review the most recent progress in imaging-based and spectrometry-based smartphone-integrated platforms that have been developed for chemical experiments and biological diagnosis. We focus on the analytical performance and the complexity for implementation of the platforms. Full article

(This article belongs to the Special Issue Sensors for Health Monitoring and Disease Diagnosis)

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31 pages, 4897 KiB

Open AccessReview

Distributed Multisensor Data Fusion under Unknown Correlation and Data Inconsistency

by Muhammad Abu Bakr and Sukhan Lee^*

Intelligent Systems Research Institute, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746, Korea

Sensors 2017, 17(11), 2472; https://doi.org/10.3390/s17112472 - 27 Oct 2017

Cited by 81 | Viewed by 9197

Abstract

The paradigm of multisensor data fusion has been evolved from a centralized architecture to a decentralized or distributed architecture along with the advancement in sensor and communication technologies. These days, distributed state estimation and data fusion has been widely explored in diverse fields [...] Read more.

The paradigm of multisensor data fusion has been evolved from a centralized architecture to a decentralized or distributed architecture along with the advancement in sensor and communication technologies. These days, distributed state estimation and data fusion has been widely explored in diverse fields of engineering and control due to its superior performance over the centralized one in terms of flexibility, robustness to failure and cost effectiveness in infrastructure and communication. However, distributed multisensor data fusion is not without technical challenges to overcome: namely, dealing with cross-correlation and inconsistency among state estimates and sensor data. In this paper, we review the key theories and methodologies of distributed multisensor data fusion available to date with a specific focus on handling unknown correlation and data inconsistency. We aim at providing readers with a unifying view out of individual theories and methodologies by presenting a formal analysis of their implications. Finally, several directions of future research are highlighted. Full article

(This article belongs to the Section Sensor Networks)

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20 pages, 265 KiB

Open AccessReview

Low-Cost Air Quality Monitoring Tools: From Research to Practice (A Workshop Summary)

by Andrea L. Clements^1,*

, William G. Griswold², Abhijit RS³, Jill E. Johnston⁴, Megan M. Herting⁴, Jacob Thorson⁵, Ashley Collier-Oxandale⁵ and Michael Hannigan⁵

¹ Office of Research and Development, Environmental Protection Agency, Research Triangle Park, NC 27711, USA

² Department of Computer Science and Engineering, University of California San Diego, La Jolla, CA 92093, USA

³ Office of Chief Scientist, Environmental Defense Fund, San Francisco, CA 94105, USA

⁴ Department of Preventive Medicine, University of Southern California, Los Angeles, CA 90089, USA

⁵ Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO 80309, USA

Sensors 2017, 17(11), 2478; https://doi.org/10.3390/s17112478 - 28 Oct 2017

Cited by 185 | Viewed by 20340

Abstract

In May 2017, a two-day workshop was held in Los Angeles (California, U.S.A.) to gather practitioners who work with low-cost sensors used to make air quality measurements. The community of practice included individuals from academia, industry, non-profit groups, community-based organizations, and regulatory agencies. [...] Read more.

In May 2017, a two-day workshop was held in Los Angeles (California, U.S.A.) to gather practitioners who work with low-cost sensors used to make air quality measurements. The community of practice included individuals from academia, industry, non-profit groups, community-based organizations, and regulatory agencies. The group gathered to share knowledge developed from a variety of pilot projects in hopes of advancing the collective knowledge about how best to use low-cost air quality sensors. Panel discussion topics included: (1) best practices for deployment and calibration of low-cost sensor systems, (2) data standardization efforts and database design, (3) advances in sensor calibration, data management, and data analysis and visualization, and (4) lessons learned from research/community partnerships to encourage purposeful use of sensors and create change/action. Panel discussions summarized knowledge advances and project successes while also highlighting the questions, unresolved issues, and technological limitations that still remain within the low-cost air quality sensor arena. Full article

(This article belongs to the Special Issue Air Pollution Sensors: A New Class of Tools to Measure Air Quality)

22 pages, 4064 KiB

Open AccessReview

Determination of Chloride Content in Cementitious Materials: From Fundamental Aspects to Application of Ag/AgCl Chloride Sensors

by Farhad Pargar^*, Dessi A. Koleva

and Klaas Van Breugel

Faculty of Civil Engineering and Geosciences, Department Materials and Environment, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands

Sensors 2017, 17(11), 2482; https://doi.org/10.3390/s17112482 - 29 Oct 2017

Cited by 50 | Viewed by 11098

Abstract

This paper reports on the advantages and drawbacks of available test methods for the determination of chloride content in cementitious materials in general, and the application of Ag/AgCl chloride sensors in particular. The main factors that affect the reliability of a chloride sensor [...] Read more.

This paper reports on the advantages and drawbacks of available test methods for the determination of chloride content in cementitious materials in general, and the application of Ag/AgCl chloride sensors in particular. The main factors that affect the reliability of a chloride sensor are presented. The thermodynamic behaviour of silver in the presence or absence of chloride ions is described and kinetic restrictions are addressed. The parameters that can affect the activity of chloride ions in the medium and/or the rate of ion exchange and dissolution/precipitation processes at the sensor’s surface are also considered. In this regard, the contribution of morphology and microstructure of the AgCl layer, binding of chloride ions and the compactness of hydration products around the chloride sensor are highlighted. The important parameters for a reliable sensor’s response are discussed and the possible causes of inaccuracies are evaluated. Full article

(This article belongs to the Section Chemical Sensors)

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32 pages, 4313 KiB

Open AccessReview

Smart Homes for Elderly Healthcare—Recent Advances and Research Challenges

by Sumit Majumder¹, Emad. Aghayi², Moein Noferesti², Hamidreza Memarzadeh-Tehran², Tapas Mondal³, Zhibo Pang⁴

and M. Jamal Deen^1,5,*

¹ Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON L8S 4L8, Canada

² Department of Network Science and Technology, Faculty of New Sciences and Technologies, University of Tehran, Tehran 141746-6191, Iran

³ Department of Pediatrics, McMaster University, Hamilton, ON L8S 4L8, Canada

⁴ ABB Corporate Research, 721 78 Vasteras, Sweden

⁵ School of Biomedical Engineering, McMaster University, Hamilton, ON L8S 4L8, Canada

Sensors 2017, 17(11), 2496; https://doi.org/10.3390/s17112496 - 31 Oct 2017

Cited by 456 | Viewed by 57497

Abstract

Advancements in medical science and technology, medicine and public health coupled with increased consciousness about nutrition and environmental and personal hygiene have paved the way for the dramatic increase in life expectancy globally in the past several decades. However, increased life expectancy has [...] Read more.

Advancements in medical science and technology, medicine and public health coupled with increased consciousness about nutrition and environmental and personal hygiene have paved the way for the dramatic increase in life expectancy globally in the past several decades. However, increased life expectancy has given rise to an increasing aging population, thus jeopardizing the socio-economic structure of many countries in terms of costs associated with elderly healthcare and wellbeing. In order to cope with the growing need for elderly healthcare services, it is essential to develop affordable, unobtrusive and easy-to-use healthcare solutions. Smart homes, which incorporate environmental and wearable medical sensors, actuators, and modern communication and information technologies, can enable continuous and remote monitoring of elderly health and wellbeing at a low cost. Smart homes may allow the elderly to stay in their comfortable home environments instead of expensive and limited healthcare facilities. Healthcare personnel can also keep track of the overall health condition of the elderly in real-time and provide feedback and support from distant facilities. In this paper, we have presented a comprehensive review on the state-of-the-art research and development in smart home based remote healthcare technologies. Full article

(This article belongs to the Special Issue Advances in Sensors for Sustainable Smart Cities and Smart Buildings)

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17 pages, 561 KiB

Open AccessReview

Fall Prediction and Prevention Systems: Recent Trends, Challenges, and Future Research Directions

by Ramesh Rajagopalan^1,*, Irene Litvan²

and Tzyy-Ping Jung³

¹ School of Engineering, University of St. Thomas, St. Paul, MN 55105, USA

² Department of Neurosciences, University of California, San Diego, CA 92093, USA

³ Institute for Neural Computation, University of California, San Diego, CA 92093, USA

Sensors 2017, 17(11), 2509; https://doi.org/10.3390/s17112509 - 1 Nov 2017

Cited by 131 | Viewed by 23274

Abstract

Fall prediction is a multifaceted problem that involves complex interactions between physiological, behavioral, and environmental factors. Existing fall detection and prediction systems mainly focus on physiological factors such as gait, vision, and cognition, and do not address the multifactorial nature of falls. In [...] Read more.

Fall prediction is a multifaceted problem that involves complex interactions between physiological, behavioral, and environmental factors. Existing fall detection and prediction systems mainly focus on physiological factors such as gait, vision, and cognition, and do not address the multifactorial nature of falls. In addition, these systems lack efficient user interfaces and feedback for preventing future falls. Recent advances in internet of things (IoT) and mobile technologies offer ample opportunities for integrating contextual information about patient behavior and environment along with physiological health data for predicting falls. This article reviews the state-of-the-art in fall detection and prediction systems. It also describes the challenges, limitations, and future directions in the design and implementation of effective fall prediction and prevention systems. Full article

(This article belongs to the Special Issue Wearable and Ambient Sensors for Healthcare and Wellness Applications)

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25 pages, 3921 KiB

Open AccessReview

A Review of Hybrid Fiber-Optic Distributed Simultaneous Vibration and Temperature Sensing Technology and Its Geophysical Applications

by Khalid Miah^1,*,†

and David K. Potter²

¹ Geophysical Engineering Department, Montana Tech of the University of Montana, Butte, MT 59701, USA

² Physics Department, University of Alberta, Edmonton, AB T6G2E1, Canada

^† Current address: 1300 West Park Street, Butte, MT 59701, USA.

Sensors 2017, 17(11), 2511; https://doi.org/10.3390/s17112511 - 1 Nov 2017

Cited by 102 | Viewed by 11700

Abstract

Distributed sensing systems can transform an optical fiber cable into an array of sensors, allowing users to detect and monitor multiple physical parameters such as temperature, vibration and strain with fine spatial and temporal resolution over a long distance. Fiber-optic distributed acoustic sensing [...] Read more.

Distributed sensing systems can transform an optical fiber cable into an array of sensors, allowing users to detect and monitor multiple physical parameters such as temperature, vibration and strain with fine spatial and temporal resolution over a long distance. Fiber-optic distributed acoustic sensing (DAS) and distributed temperature sensing (DTS) systems have been developed for various applications with varied spatial resolution, and spectral and sensing range. Rayleigh scattering-based phase optical time domain reflectometry (OTDR) for vibration and Raman/Brillouin scattering-based OTDR for temperature and strain measurements have been developed over the past two decades. The key challenge has been to find a methodology that would enable the physical parameters to be determined at any point along the sensing fiber with high sensitivity and spatial resolution, yet within acceptable frequency range for dynamic vibration, and temperature detection. There are many applications, especially in geophysical and mining engineering where simultaneous measurements of vibration and temperature are essential. In this article, recent developments of different hybrid systems for simultaneous vibration, temperature and strain measurements are analyzed based on their operation principles and performance. Then, challenges and limitations of the systems are highlighted for geophysical applications. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Canada 2017)

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21 pages, 5293 KiB

Open AccessReview

Molecular Biosensors for Electrochemical Detection of Infectious Pathogens in Liquid Biopsies: Current Trends and Challenges

by Susana Campuzano^*

, Paloma Yáñez-Sedeño and José Manuel Pingarrón^*

Departamento de Química Analítica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain

Sensors 2017, 17(11), 2533; https://doi.org/10.3390/s17112533 - 3 Nov 2017

Cited by 40 | Viewed by 8043

Abstract

Rapid and reliable diagnosis of infectious diseases caused by pathogens, and timely initiation of appropriate treatment are critical determinants to promote optimal clinical outcomes and general public health. Conventional in vitro diagnostics for infectious diseases are time-consuming and require centralized laboratories, experienced personnel [...] Read more.

Rapid and reliable diagnosis of infectious diseases caused by pathogens, and timely initiation of appropriate treatment are critical determinants to promote optimal clinical outcomes and general public health. Conventional in vitro diagnostics for infectious diseases are time-consuming and require centralized laboratories, experienced personnel and bulky equipment. Recent advances in electrochemical affinity biosensors have demonstrated to surpass conventional standards in regards to time, simplicity, accuracy and cost in this field. The tremendous potential offered by electrochemical affinity biosensors to detect on-site infectious pathogens at clinically relevant levels in scarcely treated body fluids is clearly stated in this review. The development and application of selected examples using different specific receptors, assay formats and electrochemical approaches focusing on the determination of specific circulating biomarkers of different molecular (genetic, regulatory and functional) levels associated with bacterial and viral pathogens are critically discussed. Existing challenges still to be addressed and future directions in this rapidly advancing and highly interesting field are also briefly pointed out. Full article

(This article belongs to the Special Issue Sensors for Toxic and Pathogen Detection)

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44 pages, 2613 KiB

Open AccessReview

The Application of EM38: Determination of Soil Parameters, Selection of Soil Sampling Points and Use in Agriculture and Archaeology

by Kurt Heil^* and Urs Schmidhalter

Chair of Plant Nutrition, Technical University of Munich, D-85350 Freising, Emil-Ramann-Str. 2, Germany

Sensors 2017, 17(11), 2540; https://doi.org/10.3390/s17112540 - 4 Nov 2017

Cited by 95 | Viewed by 13843

Abstract

Fast and accurate assessment of within-field variation is essential for detecting field-wide heterogeneity and contributing to improvements in the management of agricultural lands. The goal of this paper is to provide an overview of field scale characterization by electromagnetic induction, firstly with a [...] Read more.

Fast and accurate assessment of within-field variation is essential for detecting field-wide heterogeneity and contributing to improvements in the management of agricultural lands. The goal of this paper is to provide an overview of field scale characterization by electromagnetic induction, firstly with a focus on the applications of EM38 to salinity, soil texture, water content and soil water turnover, soil types and boundaries, nutrients and N-turnover and soil sampling designs. Furthermore, results concerning special applications in agriculture, horticulture and archaeology are included. In addition to these investigations, this survey also presents a wide range of practical methods for use. Secondly, the effectiveness of conductivity readings for a specific target in a specific locality is determined by the intensity at which soil factors influence these values in relationship to the desired information. The interpretation and utility of apparent electrical conductivity (EC_a) readings are highly location- and soil-specific, so soil properties influencing the measurement of EC_a must be clearly understood. From the various calibration results, it appears that regression constants for the relationships between EC_a, electrical conductivity of aqueous soil extracts (EC_e), texture, yield, etc., are not necessarily transferable from one region to another. The modelling of EC_a, soil properties, climate and yield are important for identifying the location to which specific utilizations of EC_a technology (e.g., EC_a₋texture relationships) can be appropriately applied. In general, the determination of absolute levels of EC_a is frequently not possible, but it appears to be quite a robust method to detect relative differences, both spatially and temporally. Often, the use of EC_a is restricted to its application as a covariate or the use of the readings in a relative sense rather than as absolute terms. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Germany)

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21 pages, 6471 KiB

Open AccessReview

Fiber Bragg Grating Dilatometry in Extreme Magnetic Field and Cryogenic Conditions

by Marcelo Jaime^1,2,*

, Carolina Corvalán Moya^2,3,4,5, Franziska Weickert⁶, Vivien Zapf¹, Fedor F. Balakirev¹, Mark Wartenbe⁶, Priscila F. S. Rosa⁷, Jonathan B. Betts¹, George Rodriguez⁸

, Scott A. Crooker¹ and Ramzy Daou⁹

¹ National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, NM 87545, USA

² Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, NM 87545, USA

³ Gerencia de Materiales, Comisión Nacional de Energia Atómica, Avda. Gral. Paz 1499, B1650KNA San Martín, Buenos Aires, Argentina

⁴ Consejo Nacional de Investigaciones Científicas y Técnicas, Godoy Cruz 2290, C1425FQB Ciudad Autónoma de Buenos Aires, Argentina

⁵ Universidad Nacional Tres de Febrero, Valentín Gómez 4828, Caseros, B1678ABJ Buenos Aires, Argentina

⁶ National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA

⁷ Condensed Matter and Magnet Science Group, Materials, Physics, and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA

⁸ Center for Integrated Nanotechnologies Group, Materials, Physics, and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA

⁹ Laboratoire de Cristallographie et Sciences des Matériaux, Normandie Université, Ecole Nationale Supérieure d'Ingénieurs de Caen, Université de Caen Normandie, Centre National de la Recherche Scientifique, 14050 Caen, France

Sensors 2017, 17(11), 2572; https://doi.org/10.3390/s17112572 - 8 Nov 2017

Cited by 29 | Viewed by 7124

Abstract

In this work, we review single mode SiO₂ fiber Bragg grating techniques for dilatometry studies of small single-crystalline samples in the extreme environments of very high, continuous, and pulsed magnetic fields of up to 150 T and at cryogenic temperatures down to [...] Read more.

In this work, we review single mode SiO₂ fiber Bragg grating techniques for dilatometry studies of small single-crystalline samples in the extreme environments of very high, continuous, and pulsed magnetic fields of up to 150 T and at cryogenic temperatures down to <1 K. Distinct millimeter-long materials are measured as part of the technique development, including metallic, insulating, and radioactive compounds. Experimental strategies are discussed for the observation and analysis of the related thermal expansion and magnetostriction of materials, which can achieve a strain sensitivity (ΔL/L) as low as a few parts in one hundred million (≈10⁻⁸). The impact of experimental artifacts, such as those originating in the temperature dependence of the fiber’s index of diffraction, light polarization rotation in magnetic fields, and reduced strain transfer from millimeter-long specimens, is analyzed quantitatively using analytic models available in the literature. We compare the experimental results with model predictions in the small-sample limit, and discuss the uncovered discrepancies. Full article

(This article belongs to the Special Issue Fiber Bragg Grating Based Sensors)

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21 pages, 3271 KiB

Open AccessReview

Carbon-Based Nanomaterials in Biomass-Based Fuel-Fed Fuel Cells

by Le Quynh Hoa^1,*

, Mun’delanji C. Vestergaard^2,* and Eiichi Tamiya³

¹ Federal Institute for Materials Research and Testing (BAM), Unter den Eichen 87, Berlin 12205, Germany

² Department of Biochemical Science and Technology, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan

³ Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan

Sensors 2017, 17(11), 2587; https://doi.org/10.3390/s17112587 - 10 Nov 2017

Cited by 27 | Viewed by 10339

Abstract

Environmental and sustainable economical concerns are generating a growing interest in biofuels predominantly produced from biomass. It would be ideal if an energy conversion device could directly extract energy from a sustainable energy resource such as biomass. Unfortunately, up to now, such a [...] Read more.

Environmental and sustainable economical concerns are generating a growing interest in biofuels predominantly produced from biomass. It would be ideal if an energy conversion device could directly extract energy from a sustainable energy resource such as biomass. Unfortunately, up to now, such a direct conversion device produces insufficient power to meet the demand of practical applications. To realize the future of biofuel-fed fuel cells as a green energy conversion device, efforts have been devoted to the development of carbon-based nanomaterials with tunable electronic and surface characteristics to act as efficient metal-free electrocatalysts and/or as supporting matrix for metal-based electrocatalysts. We present here a mini review on the recent advances in carbon-based catalysts for each type of biofuel-fed/biofuel cells that directly/indirectly extract energy from biomass resources, and discuss the challenges and perspectives in this developing field. Full article

(This article belongs to the Special Issue Dedication to Professor Eiichi Tamiya: Over 30 Years of Outstanding Contributions to the Field of Sensors and Biosensors)

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16 pages, 794 KiB

Open AccessReview

An Investigation into Spike-Based Neuromorphic Approaches for Artificial Olfactory Systems

by Anup Vanarse^*

, Adam Osseiran and Alexander Rassau

School of Engineering, Edith Cowan University, 6027 Perth, Australia

Sensors 2017, 17(11), 2591; https://doi.org/10.3390/s17112591 - 10 Nov 2017

Cited by 31 | Viewed by 7233

Abstract

The implementation of neuromorphic methods has delivered promising results for vision and auditory sensors. These methods focus on mimicking the neuro-biological architecture to generate and process spike-based information with minimal power consumption. With increasing interest in developing low-power and robust chemical sensors, the [...] Read more.

The implementation of neuromorphic methods has delivered promising results for vision and auditory sensors. These methods focus on mimicking the neuro-biological architecture to generate and process spike-based information with minimal power consumption. With increasing interest in developing low-power and robust chemical sensors, the application of neuromorphic engineering concepts for electronic noses has provided an impetus for research focusing on improving these instruments. While conventional e-noses apply computationally expensive and power-consuming data-processing strategies, neuromorphic olfactory sensors implement the biological olfaction principles found in humans and insects to simplify the handling of multivariate sensory data by generating and processing spike-based information. Over the last decade, research on neuromorphic olfaction has established the capability of these sensors to tackle problems that plague the current e-nose implementations such as drift, response time, portability, power consumption and size. This article brings together the key contributions in neuromorphic olfaction and identifies future research directions to develop near-real-time olfactory sensors that can be implemented for a range of applications such as biosecurity and environmental monitoring. Furthermore, we aim to expose the computational parallels between neuromorphic olfaction and gustation for future research focusing on the correlation of these senses. Full article

(This article belongs to the Special Issue Electronic Tongues and Electronic Noses)

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20 pages, 5456 KiB

Open AccessReview

Review of Recent Inkjet-Printed Capacitive Tactile Sensors

by Ahmed Salim and Sungjoon Lim^*

School of Electrical and Electronics Engineering, College of Engineering, Chung-Ang University, 221, Heukseok-Dong, Dongjak-Gu, Seoul 156-756, Korea

Sensors 2017, 17(11), 2593; https://doi.org/10.3390/s17112593 - 10 Nov 2017

Cited by 86 | Viewed by 14557

Abstract

Inkjet printing is an advanced printing technology that has been used to develop conducting layers, interconnects and other features on a variety of substrates. It is an additive manufacturing process that offers cost-effective, lightweight designs and simplifies the fabrication process with little effort. [...] Read more.

Inkjet printing is an advanced printing technology that has been used to develop conducting layers, interconnects and other features on a variety of substrates. It is an additive manufacturing process that offers cost-effective, lightweight designs and simplifies the fabrication process with little effort. There is hardly sufficient research on tactile sensors and inkjet printing. Advancements in materials science and inkjet printing greatly facilitate the realization of sophisticated tactile sensors. Starting from the concept of capacitive sensing, a brief comparison of printing techniques, the essential requirements of inkjet-printing and the attractive features of state-of-the art inkjet-printed tactile sensors developed on diverse substrates (paper, polymer, glass and textile) are presented in this comprehensive review. Recent trends in inkjet-printed wearable/flexible and foldable tactile sensors are evaluated, paving the way for future research. Full article

(This article belongs to the Special Issue Tactile Sensors and Sensing)

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13 pages, 1480 KiB

Open AccessReview

Potential Applications and Limitations of Electronic Nose Devices for Plant Disease Diagnosis

by Antonio Cellini

, Sonia Blasioli, Enrico Biondi, Assunta Bertaccini, Ilaria Braschi and Francesco Spinelli^*

Department of Agricultural Sciences, Alma Mater Studiorum—University of Bologna, viale G. Fanin 44, 40127 Bologna, Italy

Sensors 2017, 17(11), 2596; https://doi.org/10.3390/s17112596 - 11 Nov 2017

Cited by 98 | Viewed by 9250

Abstract

Electronic nose technology has recently been applied to the detection of several plant diseases and pests, with promising results. However, in spite of its numerous advantages, including operational simplicity, non-destructivity, and bulk sampling, drawbacks include a low sensitivity and specificity in comparison with [...] Read more.

Electronic nose technology has recently been applied to the detection of several plant diseases and pests, with promising results. However, in spite of its numerous advantages, including operational simplicity, non-destructivity, and bulk sampling, drawbacks include a low sensitivity and specificity in comparison with microbiological and molecular methods. A critical review of the use of an electronic nose for plant disease diagnosis and pest detection is presented, describing the instrumental and procedural advances of sensorial analysis, for the improvement of discrimination between healthy and infected or infested plants. In conclusion, the use of electronic nose technology is suggested to assist, direct, and optimise traditionally adopted diagnostic techniques. Full article

(This article belongs to the Section Chemical Sensors)

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12 pages, 922 KiB

Open AccessReview

Biosensors to Diagnose Chagas Disease: A Brief Review

by María-Isabel Rocha-Gaso¹, Luis-Jesús Villarreal-Gómez²

, Denis Beyssen³, Frédéric Sarry³, Marco-Antonio Reyna²

and Carlos-Napoleón Ibarra-Cerdeña^4,*

¹ Departamento de Ciencias Computacionales, Universidad de Quintana Roo, Unidad Cancún, 77519 Cancún, Mexico

² Escuela de Ciencias de la Ingeniería y Tecnología, Cuerpo Académico de Bioingeniería y Salud Ambiental, Universidad Autónoma de Baja California, 22260 Tijuana, Mexico

³ Institut Jean Lamour, 54600 Villers-lès-Nancy, France

⁴ Departamento de Ecología Humana, Cinvestav Unidad Mérida, 97310 Mérida, Mexico

Sensors 2017, 17(11), 2629; https://doi.org/10.3390/s17112629 - 15 Nov 2017

Cited by 13 | Viewed by 6348

Abstract

Chagas disease (CD), which mostly affects those living in deprived areas, has become one of Latin America’s main public health problems. Effective prevention of the disease requires early diagnosis, initiation of therapy, and regular blood monitoring of the infected individual. However, the majority [...] Read more.

Chagas disease (CD), which mostly affects those living in deprived areas, has become one of Latin America’s main public health problems. Effective prevention of the disease requires early diagnosis, initiation of therapy, and regular blood monitoring of the infected individual. However, the majority of the Trypanosoma cruzi infections go undiagnosed because of mild symptoms, limited access to medical attention and to a high variability in the sensitivity and specificity of diagnostic tests. Consequently, more affordable and accessible detection technologies capable of providing early diagnosis and T. cruzi load measurements in settings where CD is most prevalent are needed to enable enhanced intervention strategies. This work analyzes the potential contribution of biosensing technologies, reviewing examples that have been tested and contrasted with traditional methods, both serological and parasitological (i.e., molecular detection by PCR), and discusses some emerging biosensing technologies that have been applied for this public health issue. Even if biosensing technologies still require further research efforts to develop portable systems, we arrive at the conclusion that biosensors could improve the accuracy of CD diagnosis and the follow-up of patients’ treatments in terms of the rapidity of results, small sample volume, high integration, ease of use, real-time and low cost detection when compared with current conventional technologies. Full article

(This article belongs to the Special Issue Sensors for Health Monitoring and Disease Diagnosis)

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20 pages, 12212 KiB

Open AccessReview

Non-Contact Sensor for Long-Term Continuous Vital Signs Monitoring: A Review on Intelligent Phased-Array Doppler Sensor Design

by Travis Hall¹, Donald Y. C. Lie^1,2,*

, Tam Q. Nguyen^1,2, Jill C. Mayeda¹, Paul E. Lie², Jerry Lopez¹ and Ron E. Banister²

¹ Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX 79409-3102, USA

² Texas Tech University Health Sciences Center, Texas Tech University, Lubbock, TX 79430, USA

Sensors 2017, 17(11), 2632; https://doi.org/10.3390/s17112632 - 15 Nov 2017

Cited by 71 | Viewed by 11215

Abstract

It has been the dream of many scientists and engineers to realize a non-contact remote sensing system that can perform continuous, accurate and long-term monitoring of human vital signs as we have seen in many Sci-Fi movies. Having an intelligible sensor system that [...] Read more.

It has been the dream of many scientists and engineers to realize a non-contact remote sensing system that can perform continuous, accurate and long-term monitoring of human vital signs as we have seen in many Sci-Fi movies. Having an intelligible sensor system that can measure and record key vital signs (such as heart rates and respiration rates) remotely and continuously without touching the patients, for example, can be an invaluable tool for physicians who need to make rapid life-and-death decisions. Such a sensor system can also effectively help physicians and patients making better informed decisions when patients’ long-term vital signs data is available. Therefore, there has been a lot of research activities on developing a non-contact sensor system that can monitor a patient’s vital signs and quickly transmit the information to healthcare professionals. Doppler-based radio-frequency (RF) non-contact vital signs (NCVS) monitoring system are particularly attractive for long term vital signs monitoring because there are no wires, electrodes, wearable devices, nor any contact-based sensors involved so the subjects may not be even aware of the ubiquitous monitoring. In this paper, we will provide a brief review on some latest development on NCVS sensors and compare them against a few novel and intelligent phased-array Doppler-based RF NCVS biosensors we have built in our labs. Some of our NCVS sensor tests were performed within a clutter-free anechoic chamber to mitigate the environmental clutters, while most tests were conducted within the typical Herman-Miller type office cubicle setting to mimic a more practical monitoring environment. Additionally, we will show the measurement data to demonstrate the feasibility of long-term NCVS monitoring. The measured data strongly suggests that our latest phased array NCVS system should be able to perform long-term vital signs monitoring intelligently and robustly, especially for situations where the subject is sleeping without hectic movements nearby. Full article

(This article belongs to the Section Biosensors)

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24 pages, 1690 KiB

Open AccessReview

Novel Tactile Sensor Technology and Smart Tactile Sensing Systems: A Review

by Liang Zou^1,*

, Chang Ge¹, Z. Jane Wang¹, Edmond Cretu¹ and Xiaoou Li^2,*

¹ Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC V6T 1Z4, Canada

² College of Medical Instruments, Shanghai University of Medicine and Health Sciences, Shanghai 201318, China

Sensors 2017, 17(11), 2653; https://doi.org/10.3390/s17112653 - 17 Nov 2017

Cited by 231 | Viewed by 24413

Abstract

During the last decades, smart tactile sensing systems based on different sensing techniques have been developed due to their high potential in industry and biomedical engineering. However, smart tactile sensing technologies and systems are still in their infancy, as many technological and system [...] Read more.

During the last decades, smart tactile sensing systems based on different sensing techniques have been developed due to their high potential in industry and biomedical engineering. However, smart tactile sensing technologies and systems are still in their infancy, as many technological and system issues remain unresolved and require strong interdisciplinary efforts to address them. This paper provides an overview of smart tactile sensing systems, with a focus on signal processing technologies used to interpret the measured information from tactile sensors and/or sensors for other sensory modalities. The tactile sensing transduction and principles, fabrication and structures are also discussed with their merits and demerits. Finally, the challenges that tactile sensing technology needs to overcome are highlighted. Full article

(This article belongs to the Special Issue Tactile Sensors and Sensing)

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19 pages, 2058 KiB

Open AccessReview

Different Ways to Apply a Measurement Instrument of E-Nose Type to Evaluate Ambient Air Quality with Respect to Odour Nuisance in a Vicinity of Municipal Processing Plants

by Bartosz Szulczyński¹, Tomasz Wasilewski², Wojciech Wojnowski³, Tomasz Majchrzak³, Tomasz Dymerski³, Jacek Namieśnik³

and Jacek Gębicki^1,*

¹ Department of Chemical and Process Engineering, Chemical Faculty, Gdansk University of Technology, 11/12 G. Narutowicza Str., 80-233 Gdańsk, Poland

² Department of Inorganic Chemistry, Faculty of Pharmacy, Medical University of Gdańsk, Al. Hallera 107, 80-416 Gdańsk, Poland

³ Department of Analytical Chemistry, Chemical Faculty, Gdansk University of Technology, 11/12 G. Narutowicza Str., 80-233 Gdańsk, Poland

Sensors 2017, 17(11), 2671; https://doi.org/10.3390/s17112671 - 19 Nov 2017

Cited by 59 | Viewed by 7141

Abstract

This review paper presents different ways to apply a measurement instrument of e-nose type to evaluate ambient air with respect to detection of the odorants characterized by unpleasant odour in a vicinity of municipal processing plants. An emphasis was put on the following [...] Read more.

This review paper presents different ways to apply a measurement instrument of e-nose type to evaluate ambient air with respect to detection of the odorants characterized by unpleasant odour in a vicinity of municipal processing plants. An emphasis was put on the following applications of the electronic nose instruments: monitoring networks, remote controlled robots and drones as well as portable devices. Moreover, this paper presents commercially available sensors utilized in the electronic noses and characterized by the limit of quantification below 1 ppm v/v, which is close to the odour threshold of some odorants. Additionally, information about bioelectronic noses being a possible alternative to electronic noses and their principle of operation and application potential in the field of air evaluation with respect to detection of the odorants characterized by unpleasant odour was provided. Full article

(This article belongs to the Special Issue Electronic Tongues and Electronic Noses)

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18 pages, 3241 KiB

Open AccessReview

Surface Plasmon Resonance Sensing of Biorecognition Interactions within the Tumor Suppressor p53 Network

by Ilaria Moscetti

, Salvatore Cannistraro^*

and Anna Rita Bizzarri

Biophysics & Nanoscience Centre, DEB, Università della Tuscia, Largo dell’Università, 01100 Viterbo, Italy

Sensors 2017, 17(11), 2680; https://doi.org/10.3390/s17112680 - 20 Nov 2017

Cited by 22 | Viewed by 6214

Abstract

Surface Plasmon Resonance (SPR) is a powerful technique to study the kinetics of biomolecules undergoing biorecognition processes, particularly suited for protein-protein interactions of biomedical interest. The potentiality of SPR was exploited to sense the interactions occurring within the network of the tumor suppressor [...] Read more.

Surface Plasmon Resonance (SPR) is a powerful technique to study the kinetics of biomolecules undergoing biorecognition processes, particularly suited for protein-protein interactions of biomedical interest. The potentiality of SPR was exploited to sense the interactions occurring within the network of the tumor suppressor p53, which is crucial for maintaining genome integrity and whose function is inactivated, mainly by down regulation or by mutation, in the majority of human tumors. This study includes p53 down-regulators, p53 mutants and also the p53 family members, p63 and p73, which could vicariate p53 protective function. Furthermore, the application of SPR was extended to sense the interaction of p53 with anti-cancer drugs, which might restore p53 function. An extended review of previous published work and unpublished kinetic data is provided, dealing with the interaction between the p53 family members, or their mutants and two anticancer molecules, Azurin and its cell-penetrating peptide, p28. All the kinetic results are discussed in connection with those obtained by a complementary approach operating at the single molecule level, namely Atomic Force Spectroscopy and the related literature data. The overview of the SPR kinetic results may significantly contribute to a deeper understanding of the interactions within p53 network, also in the perspective of designing suitable anticancer drugs. Full article

(This article belongs to the Special Issue Surface Plasmon Resonance Sensing)

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26 pages, 32795 KiB

Open AccessReview

Selectivity/Specificity Improvement Strategies in Surface-Enhanced Raman Spectroscopy Analysis

by Feng Wang^*, Shiyu Cao, Ruxia Yan, Zewei Wang, Dan Wang and Haifeng Yang^*

The Education Ministry Key Lab of Resource Chemistry, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Municipal Education Committee Key Laboratory of Molecular Imaging Probes and Sensors, and Department of Chemistry, Shanghai Normal University, Shanghai 200234, China

Sensors 2017, 17(11), 2689; https://doi.org/10.3390/s17112689 - 21 Nov 2017

Cited by 66 | Viewed by 9875

Abstract

Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for the discrimination, identification, and potential quantification of certain compounds/organisms. However, its real application is challenging due to the multiple interference from the complicated detection matrix. Therefore, selective/specific detection is crucial for the real application [...] Read more.

Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for the discrimination, identification, and potential quantification of certain compounds/organisms. However, its real application is challenging due to the multiple interference from the complicated detection matrix. Therefore, selective/specific detection is crucial for the real application of SERS technique. We summarize in this review five selective/specific detection techniques (chemical reaction, antibody, aptamer, molecularly imprinted polymers and microfluidics), which can be applied for the rapid and reliable selective/specific detection when coupled with SERS technique. Full article

(This article belongs to the Special Issue Surface Plasmon Resonance Sensing)

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Jump to: Research, Review

13 pages, 4317 KiB

Open AccessLetter

Power Allocation Scheme for Non-Orthogonal Multiple Access in Underwater Acoustic Communications

by Jinyong Cheon and Ho-Shin Cho^*

School of Electronics Engineering, Kyungpook National University, Daegu 41566, Korea

Sensors 2017, 17(11), 2465; https://doi.org/10.3390/s17112465 - 27 Oct 2017

Cited by 30 | Viewed by 7503

Abstract

In this paper, we propose a power allocation scheme for non-orthogonal multiple access (NOMA) in underwater acoustic sensor networks (UWASNs). The existing terrestrial sum-rate maximization (SRM) power allocation scheme suffers from the degradation of the overall sum-rate in UWASNs due to wasteful resource [...] Read more.

In this paper, we propose a power allocation scheme for non-orthogonal multiple access (NOMA) in underwater acoustic sensor networks (UWASNs). The existing terrestrial sum-rate maximization (SRM) power allocation scheme suffers from the degradation of the overall sum-rate in UWASNs due to wasteful resource created by unequal transmission times between each transmission path. To address this issue, we propose the equal transmission times (ETT) power allocation scheme, which can prevent wasteful resource generation by guaranteeing equal transmission times between each transmission path. ETT considers the number of packets waiting for transmission in the sender’s buffer for creating equal transmission times. Numerical results show that the proposed ETT outperforms SRM in terms of the overall sum-rate, while having nearly identical maximum sum-rate to the SRMs. Full article

(This article belongs to the Special Issue Advances and Challenges in Underwater Sensor Networks)

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6 pages, 2289 KiB

Open AccessLetter

High-Order Modes Micro-Knot Excited by a Long-Period Fiber Grating

by Shir Shahal, Hamootal Duadi and Moti Fridman^*

Faculty of Engineering and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel

Sensors 2017, 17(11), 2490; https://doi.org/10.3390/s17112490 - 30 Oct 2017

Cited by 25 | Viewed by 4100

Abstract

We suggest a fiber micro-knot fabricated on a long-period fiber grating. The long-period fiber grating excites high-order modes into the micro-knot and transfers the output back to the Gaussian mode. We show theoretically and experimentally that these micro-knots have an improved Q-factor, higher [...] Read more.

We suggest a fiber micro-knot fabricated on a long-period fiber grating. The long-period fiber grating excites high-order modes into the micro-knot and transfers the output back to the Gaussian mode. We show theoretically and experimentally that these micro-knots have an improved Q-factor, higher stability, and have an increased evanescence wave coupling to the environment than single mode fiber micro-knots. These high-order fiber micro-knots can be beneficial for various fiber detectors and optical data processing systems. Full article

(This article belongs to the Special Issue Fiber Bragg Grating Based Sensors)

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1 pages, 142 KiB

Open AccessErratum

Erratum: Al-Fandi, M.; et al. Novel Selective Detection Method of Tumor Angiogenesis Factors Using Living Nano-Robots. Sensors 2017, 17, 1580

by Mohamed Al-Fandi^1,3,*

, Nida Alshraiedeh², Rami Oweis¹, Hala Alshdaifat³, Omamah Al-Mahaseneh³, Khadijah Al-Tall³ and Rawan Alawneh³

¹ Nanotechnology Institute, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan

² Faculty of Pharmacy, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan

³ Micro and Nano Systems Lab., Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan

Sensors 2017, 17(11), 2492; https://doi.org/10.3390/s17112492 - 30 Oct 2017

Cited by 2 | Viewed by 3521

Abstract

The authors wish to correct the spelling of the third author’s name from Rami Owies to Rami Oweis in their paper published in Sensors [1], doi:10.3390/s17071580, https://www.mdpi.com/1424- 8220/17/7/1580.[...] Full article

(This article belongs to the Special Issue Biosensors for Cancer Biomarkers)

1 pages, 132 KiB

Open AccessCorrection

Correction: A New Quaternion-Based Kalman Filter for Real-Time Attitude Estimation Using the Two-Step Geometrically-Intuitive Correction Algorithm. Sensors 2017, 17, 2146

by Kaiqiang Feng^1,2, Jie Li^1,2,*, Xiaoming Zhang^1,2, Chong Shen^1,2

, Yu Bi^1,2, Tao Zheng^1,2 and Jun Liu^1,2

¹ Key Laboratory of instrumentation Science & Dynamic Measurement, Ministry of Education, North University of China, Taiyuan 030051, China

² National Key Laboratory for Electronic Measurement Technology, North University of China, Taiyuan 030051, China

Sensors 2017, 17(11), 2530; https://doi.org/10.3390/s17112530 - 3 Nov 2017

Cited by 8 | Viewed by 3391

Abstract

The authors wish to make the following corrections to their paper [...] Full article

42 pages, 5580 KiB

Open AccessProject Report

HDOMO: Smart Sensor Integration for an Active and Independent Longevity of the Elderly

by Emanuele Frontoni^*

, Rama Pollini, Paola Russo

, Primo Zingaretti

and Graziano Cerri

Department of Information Engineering, Università Politecnica delle Marche, I-60131 Ancona, Italy

Sensors 2017, 17(11), 2610; https://doi.org/10.3390/s17112610 - 13 Nov 2017

Cited by 23 | Viewed by 6949

Abstract

The aim of this paper is to present the main results of HDOMO, an Ambient Assisted Living (AAL) project that involved 16 Small and Medium Enterprises (SMEs) and 2 research institutes. The objective of the project was to create an autonomous and automated [...] Read more.

The aim of this paper is to present the main results of HDOMO, an Ambient Assisted Living (AAL) project that involved 16 Small and Medium Enterprises (SMEs) and 2 research institutes. The objective of the project was to create an autonomous and automated domestic environment, primarily for elderly people and people with physical and motor disabilities. A known and familiar environment should help users in their daily activities and it should act as a virtual caregiver by calling, if necessary, relief efforts. Substantially, the aim of the project is to simplify the life of people in need of support, while keeping them autonomous in their private environment. From a technical point of view, the project provides the use of different Smart Objects (SOs), able to communicate among each other, in a cloud base infrastructure, and with the assisted users and their caregivers, in a perspective of interoperability and standardization of devices, usability and effectiveness of alarm systems. In the state of the art there are projects that achieve only a few of the elements listed. The HDOMO project aims to achieve all of them in one single project effectively. The experimental trials performed in a real scenario demonstrated the accuracy and efficiency of the system in extracting and processing data in real time to promptly acting, and in providing timely response to the needs of the user by integrating and confirming main alarms with different interoperable smart sensors. The article proposes a new technique to improve the accuracy of the system in detecting alarms using a multi-SO approach with information fusion between different devices, proving that this architecture can provide robust and reliable results on real environments. Full article

(This article belongs to the Special Issue Sensors and Sensing in Indoor Localization, Tracking, Navigation and Activity Monitoring)

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7 pages, 641 KiB

Open AccessObituary

In Memoriam: Paolo Cappa

by Eduardo Palermo¹

, Stefano Rossi²

, Fabrizio Patanè³, Jeffrey Laut⁴ and Maurizio Porfiri^4,*

¹ Department of Mechanical and Aerospace Engineering, Sapienza University of Rome, 00184 Rome, Italy

² Department of Economics, Engineering, Society and Business Organization (DEIM), University of Tuscia, 01100 Viterbo, Italy

³ Niccolò Cusano University, via Don Gnocchi, 00166 Rome, Italy

⁴ Department of Mechanical and Aerospace Engineering, New York University Tandon School of Engineering, Brooklyn, NY 11201, USA

Sensors 2017, 17(11), 2661; https://doi.org/10.3390/s17112661 - 18 Nov 2017

Viewed by 4680

Abstract

Prof. Paolo Cappa passed away on 26 August 2016, at the age of 59, after a long and courageous fight against cancer. Paolo Cappa was a Professor in Mechanical and Thermal Measurements and Experimental Biomechanics in the Department of Mechanical and Aerospace Engineering [...] Read more.

Prof. Paolo Cappa passed away on 26 August 2016, at the age of 59, after a long and courageous fight against cancer. Paolo Cappa was a Professor in Mechanical and Thermal Measurements and Experimental Biomechanics in the Department of Mechanical and Aerospace Engineering of Sapienza University of Rome, where he had also served as the Head of the Department, and a Research Professor in the Department of Mechanical and Aerospace Engineering of New York University Tandon School of Engineering. During his intense, yet short, career, he made several significant scientific contributions within the discipline of Mechanical and Thermal Measurements, pioneering fundamental applications to Biomechanics. He co-founded the Motion Analysis and Robotics Laboratory (MARLab) within the Neurorehabilitation Division of IRCCS Pediatric Hospital “Bambino Gesu”, in Rome, to fuel transitional research from the laboratory to clinical practice. Through collaboration with neurologists and physiatrists at MARLab, Prof. Cappa led the development of a powerful array of novel mechanical solutions to wearable robotics for pediatric patients, addressing dramatic needs for children’s health and contributing to the training of an entire generation of Mechanical Engineering students. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Italy 2017)

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