Sensors

Research

24 pages, 345 KiB

Open AccessArticle

Improving Biometric-Based Authentication Schemes with Smart Card Revocation/Reissue for Wireless Sensor Networks

by Jongho Moon¹

, Donghoon Lee¹, Youngsook Lee² and Dongho Won^3,*

¹ Department of Electrical and Computer Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 16419, Korea

² Department of Cyber Security, Howon University, 64 Howondae 3-gil, Impi-myeon, Gunsan-si, Jeonrabuk-do 54058, Korea

³ Department of Computer Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 16419, Korea

Sensors 2017, 17(5), 940; https://doi.org/10.3390/s17050940 - 25 Apr 2017

Cited by 86 | Viewed by 5052

Abstract

User authentication in wireless sensor networks is more difficult than in traditional networks owing to sensor network characteristics such as unreliable communication, limited resources, and unattended operation. For these reasons, various authentication schemes have been proposed to provide secure and efficient communication. In [...] Read more.

User authentication in wireless sensor networks is more difficult than in traditional networks owing to sensor network characteristics such as unreliable communication, limited resources, and unattended operation. For these reasons, various authentication schemes have been proposed to provide secure and efficient communication. In 2016, Park et al. proposed a secure biometric-based authentication scheme with smart card revocation/reissue for wireless sensor networks. However, we found that their scheme was still insecure against impersonation attack, and had a problem in the smart card revocation/reissue phase. In this paper, we show how an adversary can impersonate a legitimate user or sensor node, illegal smart card revocation/reissue and prove that Park et al.’s scheme fails to provide revocation/reissue. In addition, we propose an enhanced scheme that provides efficiency, as well as anonymity and security. Finally, we provide security and performance analysis between previous schemes and the proposed scheme, and provide formal analysis based on the random oracle model. The results prove that the proposed scheme can solve the weaknesses of impersonation attack and other security flaws in the security analysis section. Furthermore, performance analysis shows that the computational cost is lower than the previous scheme. Full article

(This article belongs to the Special Issue Sensors for Home Automation and Security)

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16 pages, 10381 KiB

Open AccessArticle

INS/GNSS Integration for Aerobatic Flight Applications and Aircraft Motion Surveying

by Edgar L. V. Hinüber^1,*, Christian Reimer¹, Tim Schneider¹ and Michael Stock²

¹ iMAR Navigation GmbH, D-66386 St. Ingbert, Germany

² Stock Flight Systems, D-82335 Berg, Germany

Sensors 2017, 17(5), 941; https://doi.org/10.3390/s17050941 - 26 Apr 2017

Cited by 36 | Viewed by 8699

Abstract

This paper presents field tests of challenging flight applications obtained with a new family of lightweight low-power INS/GNSS (inertial navigation system/global satellite navigation system) solutions based on MEMS (micro-electro-mechanical- sensor) machined sensors, being used for UAV (unmanned aerial [...] Read more.

This paper presents field tests of challenging flight applications obtained with a new family of lightweight low-power INS/GNSS (inertial navigation system/global satellite navigation system) solutions based on MEMS (micro-electro-mechanical- sensor) machined sensors, being used for UAV (unmanned aerial vehicle) navigation and control as well as for aircraft motion dynamics analysis and trajectory surveying. One key is a 42+ state extended Kalman-filter-based powerful data fusion, which also allows the estimation and correction of parameters that are typically affected by sensor aging, especially when applying MEMS-based inertial sensors, and which is not yet deeply considered in the literature. The paper presents the general system architecture, which allows iMAR Navigation the integration of all classes of inertial sensors and GNSS (global navigation satellite system) receivers from very-low-cost MEMS and high performance MEMS over FOG (fiber optical gyro) and RLG (ring laser gyro) up to HRG (hemispherical resonator gyro) technology, and presents detailed flight test results obtained under extreme flight conditions. As a real-world example, the aerobatic maneuvers of the World Champion 2016 (Red Bull Air Race) are presented. Short consideration is also given to surveying applications, where the ultimate performance of the same data fusion, but applied on gravimetric surveying, is discussed. Full article

(This article belongs to the Special Issue Inertial Sensors and Systems 2016)

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15 pages, 15606 KiB

Open AccessArticle

Adaptive Interference Cancellation of ECG Signals

by Aifeng Ren¹, Zhenxing Du¹, Juan Li¹, Fangming Hu¹, Xiaodong Yang^1,* and Haider Abbas^2,3,4

¹ School of Electronic Engineering, Xidian University, Xi’an 710071, China

² King Saud University, Riyadh 11653, Saudi Arabia

³ National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan

⁴ Department of Computer Sciences, Florida Institute of Technology (FIT), Melbourne, FL 32901, USA

Sensors 2017, 17(5), 942; https://doi.org/10.3390/s17050942 - 25 Apr 2017

Cited by 24 | Viewed by 8255

Abstract

As an important biological signal, electrocardiogram (ECG) signals provide a valuable basis for the clinical diagnosis and treatment of several diseases. However, its reference significance is based on the effective acquisition and correct recognition of ECG signals. In fact, this mV-level weak signal [...] Read more.

As an important biological signal, electrocardiogram (ECG) signals provide a valuable basis for the clinical diagnosis and treatment of several diseases. However, its reference significance is based on the effective acquisition and correct recognition of ECG signals. In fact, this mV-level weak signal can be easily affected by various interferences caused by the power of magnetic field, patient respiratory motion or contraction, and so on from the sampling terminal to the receiving and display end. The overlapping interference affects the quality of ECG waveform, leading to the false detection and recognition of wave groups, and thus causing misdiagnosis or faulty treatment. Therefore, the elimination of the interference of the ECG signal and the subsequent wave group identification technology has been a hot research topic, and their study has important significance. Based on the above, this paper introduces two improved adaptive algorithms based on the classical least mean square (LMS) algorithm by introducing symbolic functions and block-processing concepts. Full article

(This article belongs to the Special Issue Advances in Body Sensor Networks: Sensors, Systems, and Applications)

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12 pages, 2413 KiB

Open AccessArticle

A Gradient-Field Pulsed Eddy Current Probe for Evaluation of Hidden Material Degradation in Conductive Structures Based on Lift-Off Invariance

by Yong Li^1,*

, Haoqing Jing¹, Ilham Mukriz Zainal Abidin² and Bei Yan¹

¹ State Key Laboratory for Strength and Vibration of Mechanical Structures, Shaanxi Engineering Research Center of NDT and Structural Integrity Evaluation, Xi’an Jiaotong University, Xi’an 710049, China

² Leading Edge NDT Technology (LENDT) Group, Malaysian Nuclear Agency, 43000 Bangi, Kajang, Selangor, Malaysia

Sensors 2017, 17(5), 943; https://doi.org/10.3390/s17050943 - 25 Apr 2017

Cited by 17 | Viewed by 6790

Abstract

Coated conductive structures are widely adopted in such engineering fields as aerospace, nuclear energy, etc. The hostile and corrosive environment leaves in-service coated conductive structures vulnerable to Hidden Material Degradation (HMD) occurring under the protection coating. It is highly demanded that HMD can [...] Read more.

Coated conductive structures are widely adopted in such engineering fields as aerospace, nuclear energy, etc. The hostile and corrosive environment leaves in-service coated conductive structures vulnerable to Hidden Material Degradation (HMD) occurring under the protection coating. It is highly demanded that HMD can be non-intrusively assessed using non-destructive evaluation techniques. In light of the advantages of Gradient-field Pulsed Eddy Current technique (GPEC) over other non-destructive evaluation methods in corrosion evaluation, in this paper the GPEC probe for quantitative evaluation of HMD is intensively investigated. Closed-form expressions of GPEC responses to HMD are formulated via analytical modeling. The Lift-off Invariance (LOI) in GPEC signals, which makes the HMD evaluation immune to the variation in thickness of the protection coating, is introduced and analyzed through simulations involving HMD with variable depths and conductivities. A fast inverse method employing magnitude and time of the LOI point in GPEC signals for simultaneously evaluating the conductivity and thickness of HMD region is proposed, and subsequently verified by finite element modeling and experiments. It has been found from the results that along with the proposed inverse method the GPEC probe is applicable to evaluation of HMD in coated conductive structures without much loss in accuracy. Full article

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

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9 pages, 7528 KiB

Open AccessArticle

A Cost-Effective Relative Humidity Sensor Based on Side Coupling Induction Technology

by Yingzi Zhang^1,2, Yulong Hou^1,2,*, Wenyi Liu^1,2, Huixin Zhang^1,2, Yanjun Zhang^1,2, Zhidong Zhang^1,2

, Jing Guo^1,2, Jia Liu^1,2, Liang Zhang^1,2 and Qiu-lin Tan^1,2

¹ Key Laboratory of Instrumentation Science & Dynamic Measurement, Ministry of Education, North University of China, Taiyuan 030051, China

² Science and Technology on Electronic Test & Measurement Laboratory, North University of China, Taiyuan 030051, China

Sensors 2017, 17(5), 944; https://doi.org/10.3390/s17050944 - 25 Apr 2017

Cited by 42 | Viewed by 5715

Abstract

A intensity-modulated optical fiber relative humidity (RH) sensor based on the side coupling induction technology (SCIT) is presented and experimentally demonstrated. The agarose gel and the twisted macro-bend coupling structure are first combined for RH sensing applications. The refractive index (RI) of the [...] Read more.

A intensity-modulated optical fiber relative humidity (RH) sensor based on the side coupling induction technology (SCIT) is presented and experimentally demonstrated. The agarose gel and the twisted macro-bend coupling structure are first combined for RH sensing applications. The refractive index (RI) of the agarose gel increases with the increase of the RH and is in linear proportion from 20 to 80%RH. The side coupling power, which changes directly with the RI of the agarose gel, can strip the source noise from the sensor signal and improve the signal to noise ratio substantially. The experiment results show that the sensitivity of the proposed sensor increases while the bend radius decreases. When the bend radius is 8 mm, the sensor has a linear response from 40% to 80% RH with the sensitivity of 4.23 nW/% and the limit of detection of 0.70%. A higher sensitivity of 12.49 nW/% is achieved when RH raises from 80% to 90% and the limit of detection decreases to 0.55%. Furthermore, the proposed sensor is a low-cost solution, offering advantages of good reversibility, fast response time, and compensable temperature dependence. Full article

(This article belongs to the Special Issue Humidity Sensors)

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23 pages, 12002 KiB

Open AccessArticle

Implementation of an Electronic Ionosonde to Monitor the Earth’s Ionosphere via a Projected Column through USRP

by Jhon Jairo Barona Mendoza^1,2,*, Carlos Fernando Quiroga Ruiz¹ and Carlos Rafael Pinedo Jaramillo³

¹ Geopositioning Laboratory, Universidad Del Valle, Cali 760036, Colombia

² ETSI Universidad Politécnica de Madrid, Madrid 28040, Spain

³ School of Electrical and Electronic Engineering, Universidad Del Valle, Cali 760036, Colombia

Sensors 2017, 17(5), 946; https://doi.org/10.3390/s17050946 - 25 Apr 2017

Cited by 8 | Viewed by 9049

Abstract

This document illustrates the processes carried out for the construction of an ionospheric sensor or ionosonde, from a universal software radio peripheral (USRP), and its programming using GNU-Radio and MATLAB. The development involved the in-depth study of the characteristics of the ionosphere, to [...] Read more.

This document illustrates the processes carried out for the construction of an ionospheric sensor or ionosonde, from a universal software radio peripheral (USRP), and its programming using GNU-Radio and MATLAB. The development involved the in-depth study of the characteristics of the ionosphere, to apply the corresponding mathematical models used in the radar-like pulse compression technique and matched filters, among others. The sensor operates by firing electromagnetic waves in a frequency sweep, which are reflected against the ionosphere and are received on its return by the receiver of the instrument, which calculates the reflection height through the signal offset. From this information and a series of calculations, the electron density of the terrestrial ionosphere could be obtained. Improving the SNR of received echoes reduces the transmission power to a maximum of 400 W. The resolution associated with the bandwidth of the signal used is approximately 5 km, but this can be improved, taking advantage of the fact that the daughterboards used in the USRP allow a higher sampling frequency than the one used in the design of this experiment. Full article

(This article belongs to the Special Issue Understanding Land Surface Processes and Ecosystem Changes with Optical and Laser Remote Sensing)

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9 pages, 1610 KiB

Open AccessArticle

Gold Nanoplates for a Localized Surface Plasmon Resonance-Based Boric Acid Sensor

by Marlia Morsin^1,2,*, Muhamad Mat Salleh³, Akrajas Ali Umar³ and Mohd Zainizan Sahdan^1,2

¹ Microelectronics & Nanotechnology-Shamsuddin Research Centre (MiNT-SRC), Institute of Integrated Engineering (I2E), Universiti Tun Hussien Onn Malaysia, Batu Pahat, Johor 86400, Malaysia

² Department of Electronic Engineering, Faculty of Electronic and Electrical Engineering, Universiti Tun Hussien Onn Malaysia, Batu Pahat, Johor 86400, Malaysia

³ Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia, Bangi, Selangor 43600, Malaysia

Sensors 2017, 17(5), 947; https://doi.org/10.3390/s17050947 - 25 Apr 2017

Cited by 35 | Viewed by 7252

Abstract

Localized surface plasmon resonance (LSPR) properties of metallic nanostructures, such as gold, are very sensitive to the dielectric environment of the material, which can simply be adjusted by changing its shape and size through modification of the synthesizing process. Thus, these unique properties [...] Read more.

Localized surface plasmon resonance (LSPR) properties of metallic nanostructures, such as gold, are very sensitive to the dielectric environment of the material, which can simply be adjusted by changing its shape and size through modification of the synthesizing process. Thus, these unique properties are very promising, particularly for the detection of various types of chemicals, for example boric acid which is a non-permitted preservative employed in food preparations. For the sensing material, gold (Au) nanoplates with a variety of shapes, i.e., triangular, hexagonal, truncated pentagon and flat rod, were prepared using a seed-mediated growth method. The yield of Au nanoplates was estimated to be ca. 63% over all areas of the sensing material. The nanoplates produced two absorption bands, i.e., the transverse surface plasmon resonance (t-SPR) and the longitudinal surface plasmon resonance (l-SPR) at 545 nm and 710 nm, respectively. In the sensing study, these two bands were used to examine the response of gold nanoplates to the presence of boric acid in an aqueous environment. In a typical process, when the sample is immersed into an aqueous solution containing boric acid, these two bands may change their intensity and peak centers as a result of the interaction between the boric acid and the gold nanoplates. The changes in the intensities and peak positions of t-SPR and l-SPR linearly correlated with the change in the boric acid concentration in the solution. Full article

(This article belongs to the Section Biosensors)

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Graphical abstract

21 pages, 16856 KiB

Open AccessArticle

Real-Time Telemetry System for Monitoring Motion of Ships Based on Inertial Sensors

by José M. Núñez^1,*

, Marta G. Araújo² and I. García-Tuñón²

¹ Centro Universitario de la Defensa (CUD), Escuela Naval Militar (ENM), Plaza de España s/n, 36920 Marín, Pontevedra, Spain

² Departamento de Teoría de la Señal y Comunicaciones, Universidad de Vigo, Campus Universitario Lagoas-Marcosende, 36310 Vigo, Pontevedra, Spain

Sensors 2017, 17(5), 948; https://doi.org/10.3390/s17050948 - 25 Apr 2017

Cited by 10 | Viewed by 8946

Abstract

A telemetry system for real-time monitoring of the motions, position, speed and course of a ship at sea is presented in this work. The system, conceived as a subsystem of a radar cross-section measurement unit, could also be used in other applications as [...] Read more.

A telemetry system for real-time monitoring of the motions, position, speed and course of a ship at sea is presented in this work. The system, conceived as a subsystem of a radar cross-section measurement unit, could also be used in other applications as ships dynamics characterization, on-board cranes, antenna stabilizers, etc. This system was designed to be stand-alone, reliable, easy to deploy, low-cost and free of requirements related to stabilization procedures. In order to achieve such a unique combination of functionalities, we have developed a telemetry system based on redundant inertial and magnetic sensors and GPS (Global Positioning System) measurements. It provides a proper data storage and also has real-time radio data transmission capabilities to an on-shore station. The output of the system can be used either for on-line or off-line processing. Additionally, the system uses dual technologies and COTS (Commercial Off-The-Shelf) components. Motion-positioning measurements and radio data link tests were successfully carried out in several ships of the Spanish Navy, proving the compliance with the design targets and validating our telemetry system. Full article

(This article belongs to the Section Physical Sensors)

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18 pages, 13543 KiB

Open AccessArticle

Design and Development of a Three-Component Force Sensor for Milling Process Monitoring

by Yingxue Li¹, Yulong Zhao^1,*, Jiyou Fei², Yafei Qin¹, You Zhao¹, Anjiang Cai³ and Song Gao¹

¹ The State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China

² School of EMU Application and Maintenance Engineering, Dalian Jiaotong University, Dalian 116028, China

³ Shaanxi Key Laboratory of Nano Materials and Technology, Xi’an University of Architecture and Technology, Xi’an 710055, China

Sensors 2017, 17(5), 949; https://doi.org/10.3390/s17050949 - 25 Apr 2017

Cited by 15 | Viewed by 5620

Abstract

A strain-type three-component table dynamometer is presented in this paper, which reduces output errors produced by cutting forces imposed on the different milling positions of a workpiece. A sensor structure with eight parallel elastic beams is proposed, and sensitive regions and Wheastone measuring [...] Read more.

A strain-type three-component table dynamometer is presented in this paper, which reduces output errors produced by cutting forces imposed on the different milling positions of a workpiece. A sensor structure with eight parallel elastic beams is proposed, and sensitive regions and Wheastone measuring circuits are also designed in consideration of eliminating the influences of the eccentric forces. To evaluate the sensor decoupling performance, both of the static calibration and dynamic milling test were implemented in different positions of the workpiece. Static experiment results indicate that the maximal deviation between the measured forces and the standard inputs is 4.58%. Milling tests demonstrate that with same machining parameters, the differences of the measured forces between different milling positions derived by the developed sensor are no larger than 6.29%. In addition, the natural frequencies of the dynamometer are kept higher than 2585.5 Hz. All the measuring results show that as a strain-type dynamometer, the developed force sensor has an improved eccentric decoupling accuracy with natural frequencies not much decreased, which owns application potential in milling process monitoring. Full article

(This article belongs to the Section Physical Sensors)

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11 pages, 1885 KiB

Open AccessArticle

A Simple, Cost-Effective Sensor for Detecting Lead Ions in Water Using Under-Potential Deposited Bismuth Sub-Layer with Differential Pulse Voltammetry (DPV)

by Yifan Dai

and Chung Chiun Liu^*

Department of Chemical & Biomolecular Engineering and Electronics Design Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA

Sensors 2017, 17(5), 950; https://doi.org/10.3390/s17050950 - 25 Apr 2017

Cited by 22 | Viewed by 7441

Abstract

This research has developed a simple to use, cost effective sensor system for the detection of lead ions in tap water. An under-potential deposited bismuth sub-layer on a thin gold film based electrochemical sensor was designed, manufactured, and evaluated. Differential pulse voltammetry (DPV) [...] Read more.

This research has developed a simple to use, cost effective sensor system for the detection of lead ions in tap water. An under-potential deposited bismuth sub-layer on a thin gold film based electrochemical sensor was designed, manufactured, and evaluated. Differential pulse voltammetry (DPV) measurement technique was employed in this detection. Tap water from the Cleveland, OH, USA regional water district was the test medium. Concentrations of lead ion in the range of 8 × 10⁻⁷ M to 5 × 10⁻⁴ M were evaluated, showing a good sensitivity over this concentration range. The calibration curve for the DPV measurements of lead ions in tap water showed excellent reproducibility with R² value of 0.970. This DPV detection system required 3–6 min to complete the detection measurement. A longer measurement time of 6 min was used for the lower lead ion concentration. The selectivity of this lead ion sensor was very good, and Fe III, Cu II, Ni II, and Mg II at a concentration level of 5 × 10⁻⁴ M did not interfere with the lead ion measurement. Full article

(This article belongs to the Section Chemical Sensors)

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26 pages, 1204 KiB

Open AccessArticle

An Improved BLE Indoor Localization with Kalman-Based Fusion: An Experimental Study

by Jenny Röbesaat¹, Peilin Zhang^2,*

, Mohamed Abdelaal³ and Oliver Theel²

¹ OFFIS—Institut für Informatik, 26121 Oldenburg, Germany

² Department of Computer Science, Carl von Ossietzky University of Oldenburg, 26111 Oldenburg, Germany

³ Institute for Parallel and Distributed Systems, University of Stuttgart, 70569 Stuttgart, Germany

Sensors 2017, 17(5), 951; https://doi.org/10.3390/s17050951 - 26 Apr 2017

Cited by 127 | Viewed by 12570

Abstract

Indoor positioning has grasped great attention in recent years. A number of efforts have been exerted to achieve high positioning accuracy. However, there exists no technology that proves its efficacy in various situations. In this paper, we propose a novel positioning method based [...] Read more.

Indoor positioning has grasped great attention in recent years. A number of efforts have been exerted to achieve high positioning accuracy. However, there exists no technology that proves its efficacy in various situations. In this paper, we propose a novel positioning method based on fusing trilateration and dead reckoning. We employ Kalman filtering as a position fusion algorithm. Moreover, we adopt an Android device with Bluetooth Low Energy modules as the communication platform to avoid excessive energy consumption and to improve the stability of the received signal strength. To further improve the positioning accuracy, we take the environmental context information into account while generating the position fixes. Extensive experiments in a testbed are conducted to examine the performance of three approaches: trilateration, dead reckoning and the fusion method. Additionally, the influence of the knowledge of the environmental context is also examined. Finally, our proposed fusion method outperforms both trilateration and dead reckoning in terms of accuracy: experimental results show that the Kalman-based fusion, for our settings, achieves a positioning accuracy of less than one meter. 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, 2214 KiB

Open AccessArticle

Mining Productive-Associated Periodic-Frequent Patterns in Body Sensor Data for Smart Home Care

by Walaa N. Ismail and Mohammad Mehedi Hassan^*

Information Systems Department, College of Computer and Information Sciences, King Saud University, Riyadh 11543, Saudi Arabia

Sensors 2017, 17(5), 952; https://doi.org/10.3390/s17050952 - 26 Apr 2017

Cited by 22 | Viewed by 6464

Abstract

The understanding of various health-oriented vital sign data generated from body sensor networks (BSNs) and discovery of the associations between the generated parameters is an important task that may assist and promote important decision making in healthcare. For example, in a smart home [...] Read more.

The understanding of various health-oriented vital sign data generated from body sensor networks (BSNs) and discovery of the associations between the generated parameters is an important task that may assist and promote important decision making in healthcare. For example, in a smart home scenario where occupants’ health status is continuously monitored remotely, it is essential to provide the required assistance when an unusual or critical situation is detected in their vital sign data. In this paper, we present an efficient approach for mining the periodic patterns obtained from BSN data. In addition, we employ a correlation test on the generated patterns and introduce productive-associated periodic-frequent patterns as the set of correlated periodic-frequent items. The combination of these measures has the advantage of empowering healthcare providers and patients to raise the quality of diagnosis as well as improve treatment and smart care, especially for elderly people in smart homes. We develop an efficient algorithm named PPFP-growth (Productive Periodic-Frequent Pattern-growth) to discover all productive-associated periodic frequent patterns using these measures. PPFP-growth is efficient and the productiveness measure removes uncorrelated periodic items. An experimental evaluation on synthetic and real datasets shows the efficiency of the proposed PPFP-growth algorithm, which can filter a huge number of periodic patterns to reveal only the correlated ones. Full article

(This article belongs to the Special Issue Advances in Body Sensor Networks: Sensors, Systems, and Applications)

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16 pages, 8582 KiB

Open AccessArticle

Consensus-Based Cooperative Control Based on Pollution Sensing and Traffic Information for Urban Traffic Networks

by Antonio Artuñedo^*

, Raúl M. Del Toro

and Rodolfo E. Haber

Centre for Automation and Robotics (CSIC—UPM), Ctra. Campo Real Km. 0.2, Arganda del Rey, 28500 Madrid, Spain

Sensors 2017, 17(5), 953; https://doi.org/10.3390/s17050953 - 26 Apr 2017

Cited by 18 | Viewed by 8180

Abstract

Nowadays many studies are being conducted to develop solutions for improving the performance of urban traffic networks. One of the main challenges is the necessary cooperation among different entities such as vehicles or infrastructure systems and how to exploit the information available through [...] Read more.

Nowadays many studies are being conducted to develop solutions for improving the performance of urban traffic networks. One of the main challenges is the necessary cooperation among different entities such as vehicles or infrastructure systems and how to exploit the information available through networks of sensors deployed as infrastructures for smart cities. In this work an algorithm for cooperative control of urban subsystems is proposed to provide a solution for mobility problems in cities. The interconnected traffic lights controller (TLC) network adapts traffic lights cycles, based on traffic and air pollution sensory information, in order to improve the performance of urban traffic networks. The presence of air pollution in cities is not only caused by road traffic but there are other pollution sources that contribute to increase or decrease the pollution level. Due to the distributed and heterogeneous nature of the different components involved, a system of systems engineering approach is applied to design a consensus-based control algorithm. The designed control strategy contains a consensus-based component that uses the information shared in the network for reaching a consensus in the state of TLC network components. Discrete event systems specification is applied for modelling and simulation. The proposed solution is assessed by simulation studies with very promising results to deal with simultaneous responses to both pollution levels and traffic flows in urban traffic networks. Full article

(This article belongs to the Special Issue Selected Papers from the 3rd International Electronic Conference on Sensors and Applications)

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15 pages, 6481 KiB

Open AccessArticle

Spectroscopic Detection of Glyphosate in Water Assisted by Laser-Ablated Silver Nanoparticles

by Rafael Eleodoro De Góes^*

, Marcia Muller

and José Luís Fabris

Graduate Program in Electrical and Computer Engineering (CPGEI), Federal University of Technology-Parana, Curitiba 80230-901, Brazil

Sensors 2017, 17(5), 954; https://doi.org/10.3390/s17050954 - 26 Apr 2017

Cited by 24 | Viewed by 8071

Abstract

Glyphosate is one of the most widely used herbicides in the world. Its safety for both human health and aquatic biomes is a subject of wide debate. There are limits to glyphosate’s presence in bodies of water, and it is usually detected through [...] Read more.

Glyphosate is one of the most widely used herbicides in the world. Its safety for both human health and aquatic biomes is a subject of wide debate. There are limits to glyphosate’s presence in bodies of water, and it is usually detected through complex analytical procedures. In this work, the presence of glyphosate is detected directly through optical interrogation of aqueous solution. For this purpose, silver nanoparticles were produced by pulsed laser ablation in liquids. Limits of detection of 0.9 mg/L and 3.2 mg/L were obtained with UV-Vis extinction and Surface Enhanced Raman spectroscopies, respectively. The sensing mechanism was evaluated in the presence of potential interferents as well as with commercial glyphosate-based herbicides. Full article

(This article belongs to the Special Issue Last Advances in Nanoplasmonics Biosensors)

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15 pages, 4390 KiB

Open AccessArticle

A Modified Lamb Wave Time-Reversal Method for Health Monitoring of Composite Structures

by Liang Zeng¹

, Jing Lin^2,* and Liping Huang¹

¹ School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China

² State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China

Sensors 2017, 17(5), 955; https://doi.org/10.3390/s17050955 - 26 Apr 2017

Cited by 37 | Viewed by 6276

Abstract

Because the time reversal operator of Lamb waves varies with frequency in composite structures, the reconstructed signal deviates from the input signal even in undamaged cases. The damage index captures the discrepancy between the two signals without differentiating the effects of time reversal [...] Read more.

Because the time reversal operator of Lamb waves varies with frequency in composite structures, the reconstructed signal deviates from the input signal even in undamaged cases. The damage index captures the discrepancy between the two signals without differentiating the effects of time reversal operator from those of damage. This results in the risk of false alarm. To solve this issue, a modified time reversal method (MTRM) is proposed. In this method, the frequency dependence of the time reversal operator is compensated by two steps. First, an amplitude modulation is placed on the input signal, which is related to the excitability, detectability, and attenuation of the Lamb wave mode. Second, the damage index is redefined to measure the deviation between the reconstructed signal and the modulated input signal. This could indicate the presence of damage with better performance. An experimental investigation is then conducted on a carbon fiber-reinforced polymer (CFRP) laminate to illustrate the effectiveness of the MTRM for identifying damage. The results show that the MTRM may provide a promising tool for health monitoring of composite structures. Full article

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

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29 pages, 2355 KiB

Open AccessArticle

Platform Architecture for Decentralized Positioning Systems

by Zakaria Kasmi^*, Abdelmoumen Norrdine and Jörg Blankenbach

Institute for Computing in Civil Engineering & Geo Information Systems, Rheinisch-Westfälische Technische Hochschule Aachen University, Mies-van-der-Rohe-Str. 1, Aachen 52074, Germany

Sensors 2017, 17(5), 957; https://doi.org/10.3390/s17050957 - 26 Apr 2017

Cited by 8 | Viewed by 6659

Abstract

A platform architecture for positioning systems is essential for the realization of a flexible localization system, which interacts with other systems and supports various positioning technologies and algorithms. The decentralized processing of a position enables pushing the application-level knowledge into a mobile station [...] Read more.

A platform architecture for positioning systems is essential for the realization of a flexible localization system, which interacts with other systems and supports various positioning technologies and algorithms. The decentralized processing of a position enables pushing the application-level knowledge into a mobile station and avoids the communication with a central unit such as a server or a base station. In addition, the calculation of the position on low-cost and resource-constrained devices presents a challenge due to the limited computing, storage capacity, as well as power supply. Therefore, we propose a platform architecture that enables the design of a system with the reusability of the components, extensibility (e.g., with other positioning technologies) and interoperability. Furthermore, the position is computed on a low-cost device such as a microcontroller, which simultaneously performs additional tasks such as data collecting or preprocessing based on an operating system. The platform architecture is designed, implemented and evaluated on the basis of two positioning systems: a field strength system and a time of arrival-based positioning system. Full article

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

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21 pages, 12717 KiB

Open AccessArticle

Multispectral LiDAR Data for Land Cover Classification of Urban Areas

by Salem Morsy^*

, Ahmed Shaker and Ahmed El-Rabbany

Department of Civil Engineering, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada

Sensors 2017, 17(5), 958; https://doi.org/10.3390/s17050958 - 26 Apr 2017

Cited by 100 | Viewed by 11405

Abstract

Airborne Light Detection And Ranging (LiDAR) systems usually operate at a monochromatic wavelength measuring the range and the strength of the reflected energy (intensity) from objects. Recently, multispectral LiDAR sensors, which acquire data at different wavelengths, have emerged. This allows for recording of [...] Read more.

Airborne Light Detection And Ranging (LiDAR) systems usually operate at a monochromatic wavelength measuring the range and the strength of the reflected energy (intensity) from objects. Recently, multispectral LiDAR sensors, which acquire data at different wavelengths, have emerged. This allows for recording of a diversity of spectral reflectance from objects. In this context, we aim to investigate the use of multispectral LiDAR data in land cover classification using two different techniques. The first is image-based classification, where intensity and height images are created from LiDAR points and then a maximum likelihood classifier is applied. The second is point-based classification, where ground filtering and Normalized Difference Vegetation Indices (NDVIs) computation are conducted. A dataset of an urban area located in Oshawa, Ontario, Canada, is classified into four classes: buildings, trees, roads and grass. An overall accuracy of up to 89.9% and 92.7% is achieved from image classification and 3D point classification, respectively. A radiometric correction model is also applied to the intensity data in order to remove the attenuation due to the system distortion and terrain height variation. The classification process is then repeated, and the results demonstrate that there are no significant improvements achieved in the overall accuracy. Full article

(This article belongs to the Special Issue Understanding Land Surface Processes and Ecosystem Changes with Optical and Laser Remote Sensing)

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22 pages, 9574 KiB

Open AccessArticle

Embedded Spherical Localization for Micro Underwater Vehicles Based on Attenuation of Electro-Magnetic Carrier Signals

by Daniel-André Duecker, A. René Geist, Michael Hengeler, Edwin Kreuzer, Marc-André Pick, Viktor Rausch and Eugen Solowjow^*

Institute of Mechanics and Ocean Engineering, Hamburg University of Technology, Hamburg 21073, Germany

Sensors 2017, 17(5), 959; https://doi.org/10.3390/s17050959 - 26 Apr 2017

Cited by 19 | Viewed by 7304

Abstract

Self-localization is one of the most challenging problems for deploying micro autonomous underwater vehicles (

μ

AUV) in confined underwater environments. This paper extends a recently-developed self-localization method that is based on the attenuation of electro-magnetic waves, to the

μ

AUV domain. We [...] Read more.

Self-localization is one of the most challenging problems for deploying micro autonomous underwater vehicles (

μ

AUV) in confined underwater environments. This paper extends a recently-developed self-localization method that is based on the attenuation of electro-magnetic waves, to the

μ

AUV domain. We demonstrate a compact, low-cost architecture that is able to perform all signal processing steps present in the original method. The system is passive with one-way signal transmission and scales to possibly large

μ

AUV fleets. It is based on the spherical localization concept. We present results from static and dynamic position estimation experiments and discuss the tradeoffs of the system. Full article

(This article belongs to the Special Issue Sensing Technologies for Autonomy and Cooperation in Underwater Networked Robot Systems)

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15 pages, 5322 KiB

Open AccessArticle

Support Vector Data Description Model to Map Specific Land Cover with Optimal Parameters Determined from a Window-Based Validation Set

by Jinshui Zhang^1,2, Zhoumiqi Yuan^1,2,*, Guanyuan Shuai³, Yaozhong Pan^1,2

and Xiufang Zhu^1,2

¹ Department of Geography, Beijing Normal University, State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing 100875, China

² Department of Resources Science and Technology, Beijing Normal University, College of Resources Science and Technology, Beijing 100875, China

³ Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI 48824, USA

Sensors 2017, 17(5), 960; https://doi.org/10.3390/s17050960 - 26 Apr 2017

Viewed by 5097

Abstract

This paper developed an approach, the window-based validation set for support vector data description (WVS-SVDD), to determine optimal parameters for support vector data description (SVDD) model to map specific land cover by integrating training and window-based validation sets. Compared to the conventional approach [...] Read more.

This paper developed an approach, the window-based validation set for support vector data description (WVS-SVDD), to determine optimal parameters for support vector data description (SVDD) model to map specific land cover by integrating training and window-based validation sets. Compared to the conventional approach where the validation set included target and outlier pixels selected visually and randomly, the validation set derived from WVS-SVDD constructed a tightened hypersphere because of the compact constraint by the outlier pixels which were located neighboring to the target class in the spectral feature space. The overall accuracies for wheat and bare land achieved were as high as 89.25% and 83.65%, respectively. However, target class was underestimated because the validation set covers only a small fraction of the heterogeneous spectra of the target class. The different window sizes were then tested to acquire more wheat pixels for validation set. The results showed that classification accuracy increased with the increasing window size and the overall accuracies were higher than 88% at all window size scales. Moreover, WVS-SVDD showed much less sensitivity to the untrained classes than the multi-class support vector machine (SVM) method. Therefore, the developed method showed its merits using the optimal parameters, tradeoff coefficient (C) and kernel width (s), in mapping homogeneous specific land cover. Full article

(This article belongs to the Special Issue Understanding Land Surface Processes and Ecosystem Changes with Optical and Laser Remote Sensing)

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9 pages, 1476 KiB

Open AccessArticle

Detection of Hepatitis B Virus M204I Mutation by Quantum Dot-Labeled DNA Probe

by Cheng Zhang^1,†, Yiping Chen^2,†, Xinmiao Liang³, Guanhua Zhang¹, Hong Ma¹

, Leng Nie⁴ and Yu Wang^1,*

¹ Liver Research Center, Beijing Friendship Hospital, Capital Medical University, National Clinical Research Center of Digestive Diseases, 95 Yong-an Road, Xicheng District, Beijing 100050, China

² Beijing Engineering Research Center for BioNanotechnology and CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, National Center for NanoScience and Technology, Beijing 100190, China

³ Beijing Entry_Exit Inspection and Quarantine Bureau, 3 Yi, Tianzhu donglu, Tianzhu Airport Industry Area, Shunyi District, Beijing 101312, China

⁴ Wuhan Wawasye Nanotech Company, No. 36 Xinjiangongmen Road, Beijing 100191, China

^† These authors contributed equally to this work.

Sensors 2017, 17(5), 961; https://doi.org/10.3390/s17050961 - 26 Apr 2017

Cited by 20 | Viewed by 7823

Abstract

Quantum dots (QDs) are semiconductor nanoparticles with a diameter of less than 10 nm, which have been widely used as fluorescent probes in biochemical analysis and vivo imaging because of their excellent optical properties. Sensitive and convenient detection of hepatitis B virus (HBV) [...] Read more.

Quantum dots (QDs) are semiconductor nanoparticles with a diameter of less than 10 nm, which have been widely used as fluorescent probes in biochemical analysis and vivo imaging because of their excellent optical properties. Sensitive and convenient detection of hepatitis B virus (HBV) gene mutations is important in clinical diagnosis. Therefore, we developed a sensitive, low-cost and convenient QDs-mediated fluorescent method for the detection of HBV gene mutations in real serum samples from chronic hepatitis B (CHB) patients who had received lamivudine or telbivudine antiviral therapy. We also evaluated the efficiency of this method for the detection of drug-resistant mutations compared with direct sequencing. In CHB, HBV DNA from the serum samples of patients with poor response or virological breakthrough can be hybridized to probes containing the M204I mutation to visualize fluorescence under fluorescence microscopy, where fluorescence intensity is related to the virus load, in our method. At present, the limits of the method used to detect HBV genetic variations by fluorescence quantum dots is 10³ IU/mL. These results show that QDs can be used as fluorescent probes to detect viral HBV DNA polymerase gene variation, and is a simple readout system without complex and expensive instruments, which provides an attractive platform for the detection of HBV M204I mutation. Full article

(This article belongs to the Special Issue Genosensing)

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10 pages, 1634 KiB

Open AccessArticle

In-Fiber Optic Salinity Sensing: A Potential Application for Offshore Concrete Structure Protection

by Dong Luo^1,*, Peng Li¹, Yanchao Yue¹, Jianxun Ma¹ and Hangzhou Yang²

¹ School of Human Settlements and Civil Engineering, Xi’an JiaoTong University, Xi’an 710048, China

² Photonics Research Centre, University of Malaya, Kuala Lumpur 50603, Malaysia

Sensors 2017, 17(5), 962; https://doi.org/10.3390/s17050962 - 4 May 2017

Cited by 11 | Viewed by 5778

Abstract

The protection of concrete structures against corrosion in marine environments has always been a challenge due to the presence of a saline solution—A natural corrosive agent to the concrete paste and steel reinforcements. The concentration of salt is a key parameter influencing the [...] Read more.

The protection of concrete structures against corrosion in marine environments has always been a challenge due to the presence of a saline solution—A natural corrosive agent to the concrete paste and steel reinforcements. The concentration of salt is a key parameter influencing the rate of corrosion. In this paper, we propose an optical fiber-based salinity sensor based on bundled multimode plastic optical fiber (POF) as a sensor probe and a concave mirror as a reflector in conjunction with an intensity modulation technique. A refractive index (RI) sensing approach is analytically investigated and the findings are in agreement with the experimental results. A maximum sensitivity of 14,847.486/RIU can be achieved at RI = 1.3525. The proposed technique is suitable for in situ measurement and monitoring of salinity in liquid. Full article

(This article belongs to the Special Issue Specialty Optical Fibers for Chemical and Biochemical Sensing: From Evanescent Waves to Plasmonic Interaction)

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22 pages, 1434 KiB

Open AccessArticle

A Type-2 Block-Component-Decomposition Based 2D AOA Estimation Algorithm for an Electromagnetic Vector Sensor Array

by Yu-Fei Gao¹, Guan Gui^2,*

, Wei Xie¹

, Yan-Bin Zou¹, Yue Yang¹ and Qun Wan¹

¹ School of Electronic Engineering, University of Electronic Science and Technology of China, No. 2006, Xiyuan Ave., West Hi-Tech Zone, Chengdu 611731, China

² College of Telecommunication and Information Engineering, Nanjing University of Posts and Telecommunications, 66 Xinmofan Road, Nanjing 210003, China

Sensors 2017, 17(5), 963; https://doi.org/10.3390/s17050963 - 27 Apr 2017

Cited by 2 | Viewed by 5094

Abstract

This paper investigates a two-dimensional angle of arrival (2D AOA) estimation algorithm for the electromagnetic vector sensor (EMVS) array based on Type-2 block component decomposition (BCD) tensor modeling. Such a tensor decomposition method can take full advantage of the multidimensional structural information of [...] Read more.

This paper investigates a two-dimensional angle of arrival (2D AOA) estimation algorithm for the electromagnetic vector sensor (EMVS) array based on Type-2 block component decomposition (BCD) tensor modeling. Such a tensor decomposition method can take full advantage of the multidimensional structural information of electromagnetic signals to accomplish blind estimation for array parameters with higher resolution. However, existing tensor decomposition methods encounter many restrictions in applications of the EMVS array, such as the strict requirement for uniqueness conditions of decomposition, the inability to handle partially-polarized signals, etc. To solve these problems, this paper investigates tensor modeling for partially-polarized signals of an L-shaped EMVS array. The 2D AOA estimation algorithm based on rank-

(L_{1}, L_{2}, \cdot)

BCD is developed, and the uniqueness condition of decomposition is analyzed. By means of the estimated steering matrix, the proposed algorithm can automatically achieve angle pair-matching. Numerical experiments demonstrate that the present algorithm has the advantages of both accuracy and robustness of parameter estimation. Even under the conditions of lower SNR, small angular separation and limited snapshots, the proposed algorithm still possesses better performance than subspace methods and the canonical polyadic decomposition (CPD) method. 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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19 pages, 497 KiB

Open AccessArticle

An Adaptive Clustering Approach Based on Minimum Travel Route Planning for Wireless Sensor Networks with a Mobile Sink

by Jiqiang Tang^*, Wu Yang, Lingyun Zhu, Dong Wang and Xin Feng

College of Computer Science and Engineering, Chongqing University of Technology, Chongqing 400054, China

Sensors 2017, 17(5), 964; https://doi.org/10.3390/s17050964 - 26 Apr 2017

Cited by 15 | Viewed by 5947

Abstract

In recent years, Wireless Sensor Networks with a Mobile Sink (WSN-MS) have been an active research topic due to the widespread use of mobile devices. However, how to get the balance between data delivery latency and energy consumption becomes a key issue of [...] Read more.

In recent years, Wireless Sensor Networks with a Mobile Sink (WSN-MS) have been an active research topic due to the widespread use of mobile devices. However, how to get the balance between data delivery latency and energy consumption becomes a key issue of WSN-MS. In this paper, we study the clustering approach by jointly considering the Route planning for mobile sink and Clustering Problem (RCP) for static sensor nodes. We solve the RCP problem by using the minimum travel route clustering approach, which applies the minimum travel route of the mobile sink to guide the clustering process. We formulate the RCP problem as an Integer Non-Linear Programming (INLP) problem to shorten the travel route of the mobile sink under three constraints: the communication hops constraint, the travel route constraint and the loop avoidance constraint. We then propose an Imprecise Induction Algorithm (IIA) based on the property that the solution with a small hop count is more feasible than that with a large hop count. The IIA algorithm includes three processes: initializing travel route planning with a Traveling Salesman Problem (TSP) algorithm, transforming the cluster head to a cluster member and transforming the cluster member to a cluster head. Extensive experimental results show that the IIA algorithm could automatically adjust cluster heads according to the maximum hops parameter and plan a shorter travel route for the mobile sink. Compared with the Shortest Path Tree-based Data-Gathering Algorithm (SPT-DGA), the IIA algorithm has the characteristics of shorter route length, smaller cluster head count and faster convergence rate. Full article

(This article belongs to the Special Issue New Advances in Identification, Information & Knowledge in the Internet of Things)

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21 pages, 12358 KiB

Open AccessArticle

A Wireless Sensor Network for Growth Environment Measurement and Multi-Band Optical Sensing to Diagnose Tree Vigor

by Shinichi Kameoka^1,†, Shuhei Isoda¹, Atsushi Hashimoto¹, Ryoei Ito¹, Satoru Miyamoto², Genki Wada³, Naoki Watanabe³, Takashi Yamakami⁴, Ken Suzuki⁴ and Takaharu Kameoka^1,*,†

¹ Graduate School of Bioresources, Mie University, 1577 Kurimamachiya-cho, Tsu City 514-8507, Mie, Japan

² Sumitomo Precision Products Co., Ltd., 1-10 Fuso-cho, Amagasaki City 660-0891, Hyogo, Japan

³ Tomi no Oka Winery, Suntory Wine International Limited, 2786, Ohnuta Kai-shi 400-0103, Yamanashi, Japan

⁴ Department of Agriculture, Kisyu Agricultural Extension Center, Mie Prefectural Government, 371 Idomachi, Kumano City 519-4300, Mie, Japan

^† These authors contributed equally to this work.

Sensors 2017, 17(5), 966; https://doi.org/10.3390/s17050966 - 27 Apr 2017

Cited by 30 | Viewed by 7032

Abstract

We have tried to develop the guidance system for farmers to cultivate using various phenological indices. As the sensing part of this system, we deployed a new Wireless Sensor Network (WSN). This system uses the 920 MHz radio wave based on the Wireless [...] Read more.

We have tried to develop the guidance system for farmers to cultivate using various phenological indices. As the sensing part of this system, we deployed a new Wireless Sensor Network (WSN). This system uses the 920 MHz radio wave based on the Wireless Smart Utility Network that enables long-range wireless communication. In addition, the data acquired by the WSN were standardized for the advanced web service interoperability. By using these standardized data, we can create a web service that offers various kinds of phenological indices as secondary information to the farmers in the field. We have also established the field management system using thermal image, fluorescent and X-ray fluorescent methods, which enable the nondestructive, chemical-free, simple, and rapid measurement of fruits or trees. We can get the information about the transpiration of plants through a thermal image. The fluorescence sensor gives us information, such as nitrate balance index (NBI), that shows the nitrate balance inside the leaf, chlorophyll content, flavonol content and anthocyanin content. These methods allow one to quickly check the health of trees and find ways to improve the tree vigor of weak ones. Furthermore, the fluorescent x-ray sensor has the possibility to quantify the loss of minerals necessary for fruit growth. Full article

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

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16 pages, 5118 KiB

Open AccessArticle

Horizontal Directional Drilling-Length Detection Technology While Drilling Based on Bi-Electro-Magnetic Sensing

by Yudan Wang, Guojun Wen^* and Han Chen

School of Mechanical and Electronic Information, China University of Geosciences, Wuhan 430074, China

Sensors 2017, 17(5), 967; https://doi.org/10.3390/s17050967 - 27 Apr 2017

Cited by 4 | Viewed by 12190

Abstract

The drilling length is an important parameter in the process of horizontal directional drilling (HDD) exploration and recovery, but there has been a lack of accurate, automatically obtained statistics regarding this parameter. Herein, a technique for real-time HDD length detection and a management [...] Read more.

The drilling length is an important parameter in the process of horizontal directional drilling (HDD) exploration and recovery, but there has been a lack of accurate, automatically obtained statistics regarding this parameter. Herein, a technique for real-time HDD length detection and a management system based on the electromagnetic detection method with a microprocessor and two magnetoresistive sensors employing the software LabVIEW are proposed. The basic principle is to detect the change in the magnetic-field strength near a current coil while the drill stem and drill-stem joint successively pass through the current coil forward or backward. The detection system consists of a hardware subsystem and a software subsystem. The hardware subsystem employs a single-chip microprocessor as the main controller. A current coil is installed in front of the clamping unit, and two magneto resistive sensors are installed on the sides of the coil symmetrically and perpendicular to the direction of movement of the drill pipe. Their responses are used to judge whether the drill-stem joint is passing through the clamping unit; then, the order of their responses is used to judge the movement direction. The software subsystem is composed of a visual software running on the host computer and a software running in the slave microprocessor. The host-computer software processes, displays, and saves the drilling-length data, whereas the slave microprocessor software operates the hardware system. A combined test demonstrated the feasibility of the entire drilling-length detection system. Full article

(This article belongs to the Section Physical Sensors)

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15 pages, 750 KiB

Open AccessArticle

Static Memory Deduplication for Performance Optimization in Cloud Computing

by Gangyong Jia¹, Guangjie Han^2,*

, Hao Wang² and Xuan Yang²

¹ Department of Computer Science and Technology, Hangzhou Dianzi University, No. 1108, Street 1, Xiasha, Hangzhou 310018, China

² Department of Information and Communication Systems, Hohai University, Jinling North Road, No. 200, Changzhou 213022, China

Sensors 2017, 17(5), 968; https://doi.org/10.3390/s17050968 - 27 Apr 2017

Cited by 48 | Viewed by 5159

Abstract

In a cloud computing environment, the number of virtual machines (VMs) on a single physical server and the number of applications running on each VM are continuously growing. This has led to an enormous increase in the demand of memory capacity and subsequent [...] Read more.

In a cloud computing environment, the number of virtual machines (VMs) on a single physical server and the number of applications running on each VM are continuously growing. This has led to an enormous increase in the demand of memory capacity and subsequent increase in the energy consumption in the cloud. Lack of enough memory has become a major bottleneck for scalability and performance of virtualization interfaces in cloud computing. To address this problem, memory deduplication techniques which reduce memory demand through page sharing are being adopted. However, such techniques suffer from overheads in terms of number of online comparisons required for the memory deduplication. In this paper, we propose a static memory deduplication (SMD) technique which can reduce memory capacity requirement and provide performance optimization in cloud computing. The main innovation of SMD is that the process of page detection is performed offline, thus potentially reducing the performance cost, especially in terms of response time. In SMD, page comparisons are restricted to the code segment, which has the highest shared content. Our experimental results show that SMD efficiently reduces memory capacity requirement and improves performance. We demonstrate that, compared to other approaches, the cost in terms of the response time is negligible. Full article

(This article belongs to the Special Issue New Advances in Identification, Information & Knowledge in the Internet of Things)

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21 pages, 1016 KiB

Open AccessArticle

Bayesian Device-Free Localization and Tracking in a Binary RF Sensor Network

by Zhenghuan Wang, Heng Liu^*, Shengxin Xu

, Xiangyuan Bu and Jianping An

School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China

Sensors 2017, 17(5), 969; https://doi.org/10.3390/s17050969 - 27 Apr 2017

Cited by 25 | Viewed by 5001

Abstract

Received-signal-strength-based (RSS-based) device-free localization (DFL) is a promising technique since it is able to localize the person without attaching any electronic device. This technology requires measuring the RSS of all links in the network constituted by several radio frequency (RF) sensors. It is [...] Read more.

Received-signal-strength-based (RSS-based) device-free localization (DFL) is a promising technique since it is able to localize the person without attaching any electronic device. This technology requires measuring the RSS of all links in the network constituted by several radio frequency (RF) sensors. It is an energy-intensive task, especially when the RF sensors work in traditional work mode, in which the sensors directly send raw RSS measurements of all links to a base station (BS). The traditional work mode is unfavorable for the power constrained RF sensors because the amount of data delivery increases dramatically as the number of sensors grows. In this paper, we propose a binary work mode in which RF sensors send the link states instead of raw RSS measurements to the BS, which remarkably reduces the amount of data delivery. Moreover, we develop two localization methods for the binary work mode which corresponds to stationary and moving target, respectively. The first localization method is formulated based on grid-based maximum likelihood (GML), which is able to achieve global optimum with low online computational complexity. The second localization method, however, uses particle filter (PF) to track the target when constant snapshots of link stats are available. Real experiments in two different kinds of environments were conducted to evaluate the proposed methods. Experimental results show that the localization and tracking performance under the binary work mode is comparable to the those in traditional work mode while the energy efficiency improves considerably. Full article

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

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21 pages, 20450 KiB

Open AccessArticle

Vibro-Shock Dynamics Analysis of a Tandem Low Frequency Resonator—High Frequency Piezoelectric Energy Harvester

by Darius Žižys^1,*

, Rimvydas Gaidys¹, Vytautas Ostaševičius² and Birutė Narijauskaitė³

¹ Faculty of Mechanical Engineering and Design, Kaunas University of Technology, Studentu 56, Kaunas LT-51368, Lithuania

² Institute of Mechatronics, Kaunas University of Technology, Studentu 56-123, Kaunas LT-51368, Lithuania

³ Faculty of Mathematics and Natural Sciences, Kaunas University of Technology, Studentu 50, Kaunas LT-51368, Lithuania

Sensors 2017, 17(5), 970; https://doi.org/10.3390/s17050970 - 27 Apr 2017

Cited by 8 | Viewed by 5110

Abstract

Frequency up-conversion is a promising technique for energy harvesting in low frequency environments. In this approach, abundantly available environmental motion energy is absorbed by a Low Frequency Resonator (LFR) which transfers it to a high frequency Piezoelectric Vibration Energy Harvester (PVEH) via impact [...] Read more.

Frequency up-conversion is a promising technique for energy harvesting in low frequency environments. In this approach, abundantly available environmental motion energy is absorbed by a Low Frequency Resonator (LFR) which transfers it to a high frequency Piezoelectric Vibration Energy Harvester (PVEH) via impact or magnetic coupling. As a result, a decaying alternating output signal is produced, that can later be collected using a battery or be transferred directly to the electric load. The paper reports an impact-coupled frequency up-converting tandem setup with different LFR to PVEH natural frequency ratios and varying contact point location along the length of the harvester. RMS power output of different frequency up-converting tandems with optimal resistive values was found from the transient analysis revealing a strong relation between power output and LFR-PVEH natural frequency ratio as well as impact point location. Simulations revealed that higher power output is obtained from a higher natural frequency ratio between LFR and PVEH, an increase of power output by one order of magnitude for a doubled natural frequency ratio and up to 150% difference in power output from different impact point locations. The theoretical results were experimentally verified. Full article

(This article belongs to the Section Physical Sensors)

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19 pages, 3256 KiB

Open AccessArticle

An Artificial Measurements-Based Adaptive Filter for Energy-Efficient Target Tracking via Underwater Wireless Sensor Networks

by Huayan Chen^1,2,†, Senlin Zhang², 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

^† This article is an expanded version of an earlier conference paper: Zhang, S.; Chen, H.; Liu, M.; Zhang, Q. Artificial Measurements Based Filter for Energy-Efficient Target Tracking in Underwater Wireless Sensor Networks. In Proceedings of the 2016 IEEE International Conference on Signal Processing, Communications and Computing (ICSPCC), Hong Kong, China, 5–8 August 2016.

Sensors 2017, 17(5), 971; https://doi.org/10.3390/s17050971 - 27 Apr 2017

Cited by 28 | Viewed by 5264

Abstract

We study the problem of energy-efficient target tracking in underwater wireless sensor networks (UWSNs). Since sensors of UWSNs are battery-powered, it is impracticable to replace the batteries when exhausted. This means that the battery life affects the lifetime of the whole network. In [...] Read more.

We study the problem of energy-efficient target tracking in underwater wireless sensor networks (UWSNs). Since sensors of UWSNs are battery-powered, it is impracticable to replace the batteries when exhausted. This means that the battery life affects the lifetime of the whole network. In order to extend the network lifetime, it is worth reducing the energy consumption on the premise of sufficient tracking accuracy. This paper proposes an energy-efficient filter that implements the tradeoff between communication cost and tracking accuracy. Under the distributed fusion framework, local sensors should not send their weak information to the fusion center if their measurement residuals are smaller than the pre-given threshold. In order to guarantee the target tracking accuracy, artificial measurements are generated to compensate for those unsent real measurements. Then, an adaptive scheme is derived to take full advantages of the artificial measurements-based filter in terms of energy-efficiency. Furthermore, a computationally efficient optimal sensor selection scheme is proposed to improve tracking accuracy on the premise of employing the same number of sensors. Simulation demonstrates that our scheme has superior advantages in the tradeoff between communication cost and tracking accuracy. It saves much energy while loosing little tracking accuracy or improves tracking performance with less additional energy cost. Full article

(This article belongs to the Special Issue Advances and Challenges in Underwater Sensor Networks)

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14 pages, 1247 KiB

Open AccessArticle

Auxiliary Truncated Unscented Kalman Filtering for Bearings-Only Maneuvering Target Tracking

by Liang-Qun Li^*, Xiao-Li Wang, Zong-Xiang Liu and Wei-Xin Xie

Automatic Target Recognition Key Laboratory (ATR), Shenzhen University, Shenzhen 518060, China

Sensors 2017, 17(5), 972; https://doi.org/10.3390/s17050972 - 27 Apr 2017

Cited by 16 | Viewed by 5115

Abstract

Novel auxiliary truncated unscented Kalman filtering (ATUKF) is proposed for bearings-only maneuvering target tracking in this paper. In the proposed algorithm, to deal with arbitrary changes in motion models, a modified prior probability density function (PDF) is derived based on some auxiliary target [...] Read more.

Novel auxiliary truncated unscented Kalman filtering (ATUKF) is proposed for bearings-only maneuvering target tracking in this paper. In the proposed algorithm, to deal with arbitrary changes in motion models, a modified prior probability density function (PDF) is derived based on some auxiliary target characteristics and current measurements. Then, the modified prior PDF is approximated as a Gaussian density by using the statistical linear regression (SLR) to estimate the mean and covariance. In order to track bearings-only maneuvering target, the posterior PDF is jointly estimated based on the prior probability density function and the modified prior probability density function, and a practical algorithm is developed. Finally, compared with other nonlinear filtering approaches, the experimental results of the proposed algorithm show a significant improvement for both the univariate nonstationary growth model (UNGM) case and bearings-only target tracking case. Full article

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

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22 pages, 10259 KiB

Open AccessArticle

A Novel MEMS Gyro North Finder Design Based on the Rotation Modulation Technique

by Yongjian Zhang

, Bin Zhou^*, Mingliang Song, Bo Hou, Haifeng Xing

and Rong Zhang^*

Engineering Research Center for Navigation Technology, Department of Precision Instrument, Tsinghua University, Beijing 100084, China

Sensors 2017, 17(5), 973; https://doi.org/10.3390/s17050973 - 28 Apr 2017

Cited by 47 | Viewed by 11664

Abstract

Gyro north finders have been widely used in maneuvering weapon orientation, oil drilling and other areas. This paper proposes a novel Micro-Electro-Mechanical System (MEMS) gyroscope north finder based on the rotation modulation (RM) technique. Two rotation modulation modes (static and dynamic modulation) are [...] Read more.

Gyro north finders have been widely used in maneuvering weapon orientation, oil drilling and other areas. This paper proposes a novel Micro-Electro-Mechanical System (MEMS) gyroscope north finder based on the rotation modulation (RM) technique. Two rotation modulation modes (static and dynamic modulation) are applied. Compared to the traditional gyro north finders, only one single MEMS gyroscope and one MEMS accelerometer are needed, reducing the total cost since high-precision gyroscopes and accelerometers are the most expensive components in gyro north finders. To reduce the volume and enhance the reliability, wireless power and wireless data transmission technique are introduced into the rotation modulation system for the first time. To enhance the system robustness, the robust least square method (RLSM) and robust Kalman filter (RKF) are applied in the static and dynamic north finding methods, respectively. Experimental characterization resulted in a static accuracy of 0.66° and a dynamic repeatability accuracy of 1°, respectively, confirming the excellent potential of the novel north finding system. The proposed single gyro and single accelerometer north finding scheme is universal, and can be an important reference to both scientific research and industrial applications. Full article

(This article belongs to the Section Physical Sensors)

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20 pages, 1184 KiB

Open AccessArticle

Time-Aware Service Ranking Prediction in the Internet of Things Environment

by Yuze Huang

, Jiwei Huang^*

, Bo Cheng, Shuqing He and Junliang Chen

State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, Beijing 100876, China

Sensors 2017, 17(5), 974; https://doi.org/10.3390/s17050974 - 27 Apr 2017

Cited by 21 | Viewed by 5504

Abstract

With the rapid development of the Internet of things (IoT), building IoT systems with high quality of service (QoS) has become an urgent requirement in both academia and industry. During the procedures of building IoT systems, QoS-aware service selection is an important concern, [...] Read more.

With the rapid development of the Internet of things (IoT), building IoT systems with high quality of service (QoS) has become an urgent requirement in both academia and industry. During the procedures of building IoT systems, QoS-aware service selection is an important concern, which requires the ranking of a set of functionally similar services according to their QoS values. In reality, however, it is quite expensive and even impractical to evaluate all geographically-dispersed IoT services at a single client to obtain such a ranking. Nevertheless, distributed measurement and ranking aggregation have to deal with the high dynamics of QoS values and the inconsistency of partial rankings. To address these challenges, we propose a time-aware service ranking prediction approach named TSRPred for obtaining the global ranking from the collection of partial rankings. Specifically, a pairwise comparison model is constructed to describe the relationships between different services, where the partial rankings are obtained by time series forecasting on QoS values. The comparisons of IoT services are formulated by random walks, and thus, the global ranking can be obtained by sorting the steady-state probabilities of the underlying Markov chain. Finally, the efficacy of TSRPred is validated by simulation experiments based on large-scale real-world datasets. Full article

(This article belongs to the Special Issue New Advances in Identification, Information & Knowledge in the Internet of Things)

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19 pages, 3451 KiB

Open AccessArticle

Shadow-Based Vehicle Detection in Urban Traffic

by Manuel Ibarra-Arenado^1,*, Tardi Tjahjadi², Juan Pérez-Oria¹, Sandra Robla-Gómez¹ and Agustín Jiménez-Avello³

¹ Control Engineering Group, University of Cantabria, Avda. Los Castros s/n, 39005 Santander, Spain

² School of Engineering, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK

³ Department of Automatics, Electronic Engineering and Industrial Computing at the Polytechnic University of Madrid, 28006 Madrid, Spain

Sensors 2017, 17(5), 975; https://doi.org/10.3390/s17050975 - 27 Apr 2017

Cited by 26 | Viewed by 7019

Abstract

Vehicle detection is a fundamental task in Forward Collision Avoiding Systems (FACS). Generally, vision-based vehicle detection methods consist of two stages: hypotheses generation and hypotheses verification. In this paper, we focus on the former, presenting a feature-based method for on-road vehicle detection in [...] Read more.

Vehicle detection is a fundamental task in Forward Collision Avoiding Systems (FACS). Generally, vision-based vehicle detection methods consist of two stages: hypotheses generation and hypotheses verification. In this paper, we focus on the former, presenting a feature-based method for on-road vehicle detection in urban traffic. Hypotheses for vehicle candidates are generated according to the shadow under the vehicles by comparing pixel properties across the vertical intensity gradients caused by shadows on the road, and followed by intensity thresholding and morphological discrimination. Unlike methods that identify the shadow under a vehicle as a road region with intensity smaller than a coarse lower bound of the intensity for road, the thresholding strategy we propose determines a coarse upper bound of the intensity for shadow which reduces false positives rates. The experimental results are promising in terms of detection performance and robustness in day time under different weather conditions and cluttered scenarios to enable validation for the first stage of a complete FACS. Full article

(This article belongs to the Special Issue Sensors for Transportation)

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14 pages, 1489 KiB

Open AccessArticle

Orthogonal Chirp-Based Ultrasonic Positioning

by Mohammad Omar Khyam^1,*

, Shuzhi Sam Ge¹, Xinde Li^1,2 and Mark Pickering³

¹ Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117580, Singapore

² Key Laboratory of Measurement and Control of CSE, School of Automation, Southeast University, Ministry of Education, Nanjing 210096, China

³ School of Engineering and Information Technology, University of New South Wales, Canberra, Campbell ACT 2612, Australia

Sensors 2017, 17(5), 976; https://doi.org/10.3390/s17050976 - 27 Apr 2017

Cited by 13 | Viewed by 6599

Abstract

This paper presents a chirp based ultrasonic positioning system (UPS) using orthogonal chirp waveforms. In the proposed method, multiple transmitters can simultaneously transmit chirp signals, as a result, it can efficiently utilize the entire available frequency spectrum. The fundamental idea behind the proposed [...] Read more.

This paper presents a chirp based ultrasonic positioning system (UPS) using orthogonal chirp waveforms. In the proposed method, multiple transmitters can simultaneously transmit chirp signals, as a result, it can efficiently utilize the entire available frequency spectrum. The fundamental idea behind the proposed multiple access scheme is to utilize the oversampling methodology of orthogonal frequency-division multiplexing (OFDM) modulation and orthogonality of the discrete frequency components of a chirp waveform. In addition, the proposed orthogonal chirp waveforms also have all the advantages of a classical chirp waveform. Firstly, the performance of the waveforms is investigated through correlation analysis and then, in an indoor environment, evaluated through simulations and experiments for ultrasonic (US) positioning. For an operational range of approximately 1000 mm, the positioning root-mean-square-errors (RMSEs) &90% error were 4.54 mm and 6.68 mm respectively. Full article

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

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25 pages, 1238 KiB

Open AccessArticle

Distributed Data Service for Data Management in Internet of Things Middleware

by Ruben Cruz Huacarpuma^1,†, Rafael Timoteo De Sousa Junior^1,†

, Maristela Terto De Holanda^2,†, Robson De Oliveira Albuquerque^1,†

, Luis Javier García Villalba^3,*,†

and Tai-Hoon Kim^4,†

¹ Cybersecurity INCT Unit 6, Decision Technologies Laboratory—LATITUDE, Electrical Engineering Department (ENE), Technology College, University of Brasília (UnB), Brasília-DF, CEP 70910-900, Brazil

² Department of Computer Science, University of Brasília (UnB), Brasília-DF, CEP 70910-900, Brazil

³ Group of Analysis, Security and Systems (GASS), Department of Software Engineering and Artificial Intelligence (DISIA), Faculty of Computer Science and Engineering, Office 431, Universidad Complutense de Madrid (UCM), Calle Profesor José García Santesmases, 9, Ciudad Universitaria, Madrid 28040, Spain

⁴ Department of Convergence Security, Sungshin Women’s University, 249-1 Dongseon-Dong 3-ga, Seoul 136-742, Korea

^† These authors contributed equally to this work.

Sensors 2017, 17(5), 977; https://doi.org/10.3390/s17050977 - 27 Apr 2017

Cited by 42 | Viewed by 9176

Abstract

The development of the Internet of Things (IoT) is closely related to a considerable increase in the number and variety of devices connected to the Internet. Sensors have become a regular component of our environment, as well as smart phones and other devices [...] Read more.

The development of the Internet of Things (IoT) is closely related to a considerable increase in the number and variety of devices connected to the Internet. Sensors have become a regular component of our environment, as well as smart phones and other devices that continuously collect data about our lives even without our intervention. With such connected devices, a broad range of applications has been developed and deployed, including those dealing with massive volumes of data. In this paper, we introduce a Distributed Data Service (DDS) to collect and process data for IoT environments. One central goal of this DDS is to enable multiple and distinct IoT middleware systems to share common data services from a loosely-coupled provider. In this context, we propose a new specification of functionalities for a DDS and the conception of the corresponding techniques for collecting, filtering and storing data conveniently and efficiently in this environment. Another contribution is a data aggregation component that is proposed to support efficient real-time data querying. To validate its data collecting and querying functionalities and performance, the proposed DDS is evaluated in two case studies regarding a simulated smart home system, the first case devoted to evaluating data collection and aggregation when the DDS is interacting with the UIoT middleware, and the second aimed at comparing the DDS data collection with this same functionality implemented within the Kaa middleware. Full article

(This article belongs to the Special Issue Topology Control in Emerging Sensor Networks)

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21 pages, 7503 KiB

Open AccessArticle

An Adaptive B-Spline Neural Network and Its Application in Terminal Sliding Mode Control for a Mobile Satcom Antenna Inertially Stabilized Platform

by Xiaolei Zhang^1,*, Yan Zhao¹, Kai Guo¹

, Gaoliang Li¹ and Nianmao Deng²

¹ School of Instrumentation Science and Opto-Electronics Engineering, Beihang University, Beijing 100191, China

² Beijing Institute of Control & Electronic Technology, Beijing 100038, China

Sensors 2017, 17(5), 978; https://doi.org/10.3390/s17050978 - 28 Apr 2017

Cited by 89 | Viewed by 5575

Abstract

The mobile satcom antenna (MSA) enables a moving vehicle to communicate with a geostationary Earth orbit satellite. To realize continuous communication, the MSA should be aligned with the satellite in both sight and polarization all the time. Because of coupling effects, unknown disturbances, [...] Read more.

The mobile satcom antenna (MSA) enables a moving vehicle to communicate with a geostationary Earth orbit satellite. To realize continuous communication, the MSA should be aligned with the satellite in both sight and polarization all the time. Because of coupling effects, unknown disturbances, sensor noises and unmodeled dynamics existing in the system, the control system should have a strong adaptability. The significant features of terminal sliding mode control method are robustness and finite time convergence, but the robustness is related to the large switching control gain which is determined by uncertain issues and can lead to chattering phenomena. Neural networks can reduce the chattering and approximate nonlinear issues. In this work, a novel B-spline curve-based B-spline neural network (BSNN) is developed. The improved BSNN has the capability of shape changing and self-adaption. In addition, the output of the proposed BSNN is applied to approximate the nonlinear function in the system. The results of simulations and experiments are also compared with those of PID method, non-singularity fast terminal sliding mode (NFTSM) control and radial basis function (RBF) neural network-based NFTSM. It is shown that the proposed method has the best performance, with reliable control precision. Full article

(This article belongs to the Section Physical Sensors)

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29 pages, 1007 KiB

Open AccessArticle

An Authentication Protocol for Future Sensor Networks

by Muhammad Bilal^* and Shin-Gak Kang

Electronics and Telecommunications Research Institute, University of Science and Technology, 218, Gajeong-ro, yuseong-gu, Daejeon 34129, Korea

Sensors 2017, 17(5), 979; https://doi.org/10.3390/s17050979 - 28 Apr 2017

Cited by 55 | Viewed by 11462

Abstract

Authentication is one of the essential security services in Wireless Sensor Networks (WSNs) for ensuring secure data sessions. Sensor node authentication ensures the confidentiality and validity of data collected by the sensor node, whereas user authentication guarantees that only legitimate users can access [...] Read more.

Authentication is one of the essential security services in Wireless Sensor Networks (WSNs) for ensuring secure data sessions. Sensor node authentication ensures the confidentiality and validity of data collected by the sensor node, whereas user authentication guarantees that only legitimate users can access the sensor data. In a mobile WSN, sensor and user nodes move across the network and exchange data with multiple nodes, thus experiencing the authentication process multiple times. The integration of WSNs with Internet of Things (IoT) brings forth a new kind of WSN architecture along with stricter security requirements; for instance, a sensor node or a user node may need to establish multiple concurrent secure data sessions. With concurrent data sessions, the frequency of the re-authentication process increases in proportion to the number of concurrent connections. Moreover, to establish multiple data sessions, it is essential that a protocol participant have the capability of running multiple instances of the protocol run, which makes the security issue even more challenging. The currently available authentication protocols were designed for the autonomous WSN and do not account for the above requirements. Hence, ensuring a lightweight and efficient authentication protocol has become more crucial. In this paper, we present a novel, lightweight and efficient key exchange and authentication protocol suite called the Secure Mobile Sensor Network (SMSN) Authentication Protocol. In the SMSN a mobile node goes through an initial authentication procedure and receives a re-authentication ticket from the base station. Later a mobile node can use this re-authentication ticket when establishing multiple data exchange sessions and/or when moving across the network. This scheme reduces the communication and computational complexity of the authentication process. We proved the strength of our protocol with rigorous security analysis (including formal analysis using the BAN-logic) and simulated the SMSN and previously proposed schemes in an automated protocol verifier tool. Finally, we compared the computational complexity and communication cost against well-known authentication protocols. Full article

(This article belongs to the Special Issue Enabling the Move from Wireless Sensor Networks to Internet of Things and Cyber-Physical Systems)

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16 pages, 4827 KiB

Open AccessArticle

Performance Analysis of Global Navigation Satellite System Signal Acquisition Aided by Different Grade Inertial Navigation System under Highly Dynamic Conditions

by Chunxi Zhang, Xianmu Li^*

, Shuang Gao, Tie Lin and Lu Wang

School of Instrument Science and Opto-electronics Engineering, Beihang University, Beijing 100191, China

Sensors 2017, 17(5), 980; https://doi.org/10.3390/s17050980 - 28 Apr 2017

Cited by 9 | Viewed by 5097

Abstract

Under the high dynamic conditions, Global Navigation Satellite System (GNSS) signals produce great Doppler frequency shifts, which hinders the fast acquisition of signals. Inertial Navigation System (INS)-aided acquisition can improve the acquisition performance, whereas the accuracy of Doppler shift and code phase estimation [...] Read more.

Under the high dynamic conditions, Global Navigation Satellite System (GNSS) signals produce great Doppler frequency shifts, which hinders the fast acquisition of signals. Inertial Navigation System (INS)-aided acquisition can improve the acquisition performance, whereas the accuracy of Doppler shift and code phase estimation are mainly determined by the INS precision. The relation between the INS accuracy and Doppler shift estimation error has been derived, while the relation between the INS accuracy and code phase estimation error has not been deduced. In this paper, in order to theoretically analyze the effects of INS errors on the performance of Doppler shift and code phase estimations, the connections between them are re-deduced. Moreover, the curves of the corresponding relations are given for the first time. Then, in order to have a better verification of the INS-aided acquisition, a high dynamic scenario is designed. Furthermore, by using the deduced mathematical relation, the effects of different grade INS on the GNSS (including Global Positioning System (GPS) and BeiDou Navigation Satellite System (BDS)) signal acquisition are analyzed. Experimental results demonstrate that the INS-aided acquisition can reduce the search range of local frequency and code phase, and achieve fast acquisition. According to the experimental results, a suitable INS can be chosen for the deeply coupled integration. Full article

(This article belongs to the Special Issue Multi-Sensor Integration and Fusion)

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22 pages, 705 KiB

Open AccessArticle

A Genetic Algorithm for the Generation of Packetization Masks for Robust Image Communication

by Katherine Zapata-Quiñones¹, Cristian Duran-Faundez^2,*

, Gilberto Gutiérrez³, Vincent Lecuire⁴, Christopher Arredondo-Flores⁵ and Hugo Jara-Lipán⁶

¹ Magister en Ciencias de la Computación, Universidad del Bío-Bío, Chillán 3800708, Chile

² Departamento de Ingeniería Eléctrica y Electrónica, Universidad del Bío-Bío, Concepción 4051381, Chile

³ Departamento de Ciencias de la Computación y Tecnologías de la Información, Universidad del Bío-Bío, Chillán 3800708, Chile

⁴ Centre de Recherche en Automatique de Nancy, Université de Lorraine, CNRS, Vandœuvre-lès-Nancy 54506, France

⁵ Magister en Informática, Universidad del Bío-Bío, Concepción 4051381, Chile

⁶ Corporación Educacional Colegio Concepción, Nuble 3800564, Chile

Sensors 2017, 17(5), 981; https://doi.org/10.3390/s17050981 - 28 Apr 2017

Cited by 3 | Viewed by 4015

Abstract

Image interleaving has proven to be an effective solution to provide the robustness of image communication systems when resource limitations make reliable protocols unsuitable (e.g., in wireless camera sensor networks); however, the search for optimal interleaving patterns is scarcely tackled in the literature. [...] Read more.

Image interleaving has proven to be an effective solution to provide the robustness of image communication systems when resource limitations make reliable protocols unsuitable (e.g., in wireless camera sensor networks); however, the search for optimal interleaving patterns is scarcely tackled in the literature. In 2008, Rombaut et al. presented an interesting approach introducing a packetization mask generator based in Simulated Annealing (SA), including a cost function, which allows assessing the suitability of a packetization pattern, avoiding extensive simulations. In this work, we present a complementary study about the non-trivial problem of generating optimal packetization patterns. We propose a genetic algorithm, as an alternative to the cited work, adopting the mentioned cost function, then comparing it to the SA approach and a torus automorphism interleaver. In addition, we engage the validation of the cost function and provide results attempting to conclude about its implication in the quality of reconstructed images. Several scenarios based on visual sensor networks applications were tested in a computer application. Results in terms of the selected cost function and image quality metric PSNR show that our algorithm presents similar results to the other approaches. Finally, we discuss the obtained results and comment about open research challenges. Full article

(This article belongs to the Section Sensor Networks)

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14 pages, 2657 KiB

Open AccessArticle

Chemiresistor Devices for Chemical Warfare Agent Detection Based on Polymer Wrapped Single-Walled Carbon Nanotubes

by John F. Fennell¹

, Hitoshi Hamaguchi², Bora Yoon¹ and Timothy M. Swager^1,*

¹ Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA

² Japanese Synthetic Rubber Company, Tokyo 105-8640, Japan

Sensors 2017, 17(5), 982; https://doi.org/10.3390/s17050982 - 28 Apr 2017

Cited by 62 | Viewed by 9335

Abstract

Chemical warfare agents (CWA) continue to present a threat to civilian populations and military personnel in operational areas all over the world. Reliable measurements of CWAs are critical to contamination detection, avoidance, and remediation. The current deployed systems in United States and foreign [...] Read more.

Chemical warfare agents (CWA) continue to present a threat to civilian populations and military personnel in operational areas all over the world. Reliable measurements of CWAs are critical to contamination detection, avoidance, and remediation. The current deployed systems in United States and foreign militaries, as well as those in the private sector offer accurate detection of CWAs, but are still limited by size, portability and fabrication cost. Herein, we report a chemiresistive CWA sensor using single-walled carbon nanotubes (SWCNTs) wrapped with poly(3,4-ethylenedioxythiophene) (PEDOT) derivatives. We demonstrate that a pendant hexafluoroisopropanol group on the polymer that enhances sensitivity to a nerve agent mimic, dimethyl methylphosphonate, in both nitrogen and air environments to concentrations as low as 5 ppm and 11 ppm, respectively. Additionally, these PEDOT/SWCNT derivative sensor systems experience negligible device performance over the course of two weeks under ambient conditions. Full article

(This article belongs to the Special Issue Chemiresistive Sensors: Status and the Future)

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14 pages, 1045 KiB

Open AccessArticle

Distributed Fault Detection Based on Credibility and Cooperation for WSNs in Smart Grids

by Sujie Shao^*

, Shaoyong Guo and Xuesong Qiu

State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, Beijing 100876, China

Sensors 2017, 17(5), 983; https://doi.org/10.3390/s17050983 - 28 Apr 2017

Cited by 18 | Viewed by 6748

Abstract

Due to the increasingly important role in monitoring and data collection that sensors play, accurate and timely fault detection is a key issue for wireless sensor networks (WSNs) in smart grids. This paper presents a novel distributed fault detection mechanism for WSNs based [...] Read more.

Due to the increasingly important role in monitoring and data collection that sensors play, accurate and timely fault detection is a key issue for wireless sensor networks (WSNs) in smart grids. This paper presents a novel distributed fault detection mechanism for WSNs based on credibility and cooperation. Firstly, a reasonable credibility model of a sensor is established to identify any suspicious status of the sensor according to its own temporal data correlation. Based on the credibility model, the suspicious sensor is then chosen to launch fault diagnosis requests. Secondly, the sending time of fault diagnosis request is discussed to avoid the transmission overhead brought about by unnecessary diagnosis requests and improve the efficiency of fault detection based on neighbor cooperation. The diagnosis reply of a neighbor sensor is analyzed according to its own status. Finally, to further improve the accuracy of fault detection, the diagnosis results of neighbors are divided into several classifications to judge the fault status of the sensors which launch the fault diagnosis requests. Simulation results show that this novel mechanism can achieve high fault detection ratio with a small number of fault diagnoses and low data congestion probability. Full article

(This article belongs to the Section Sensor Networks)

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18 pages, 1858 KiB

Open AccessArticle

A Double Rate Localization Algorithm with One Anchor for Multi-Hop Underwater Acoustic Networks

by Jingjie Gao^1,2, Xiaohong Shen^1,2, Ruiqin Zhao^1,2, Haodi Mei^1,2 and Haiyan Wang^1,2,*

¹ Key Laboratory of Ocean Acoustics and Sensing, Northwestern Polytechnical University, Ministry of Industry and Information Technology, Xi’an 710072, China

² School of Marine Science and Technology, Northwestern Polytechnical University, Xi’an 710072, China

Sensors 2017, 17(5), 984; https://doi.org/10.3390/s17050984 - 28 Apr 2017

Cited by 11 | Viewed by 4779

Abstract

Localization is a basic issue for underwater acoustic networks (UANs). Currently, most localization algorithms only perform well in one-hop networks or need more anchors which are not suitable for the underwater environment. In this paper, we proposed a double rate localization algorithm with [...] Read more.

Localization is a basic issue for underwater acoustic networks (UANs). Currently, most localization algorithms only perform well in one-hop networks or need more anchors which are not suitable for the underwater environment. In this paper, we proposed a double rate localization algorithm with one anchor for multi-hop underwater acoustic networks (DRL). The algorithm firstly presents a double rate scheme which separates the localization procedure into two modes to increase the ranging accuracy in multi-hop UANs while maintaining the transmission rate. Then an optimal selection scheme of reference nodes was proposed to reduce the influence of references’ topology on localization performance. The proposed DRL algorithm can be used in the multi-hop UANs to increase the localization accuracy and reduce the usage of anchor nodes. The simulation and experimental results demonstrated that the proposed DRL algorithm has a better localization performance than the previous algorithms in many aspects such as accuracy and communication cost, and is more suitable to the underwater environment. Full article

(This article belongs to the Special Issue Advances and Challenges in Underwater Sensor Networks)

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9 pages, 2706 KiB

Open AccessArticle

A Consistency Evaluation and Calibration Method for Piezoelectric Transmitters

by Kai Zhang^1,*, Baohai Tan¹ and Xianping Liu²

¹ School of Geosciences and Technology, China University of Petroleum, Qingdao 266555, China

² Logging Branch of China National Petroleum Corporation Bohai Drilling Engineering CO. LTD., Tianjin 300280, China

Sensors 2017, 17(5), 985; https://doi.org/10.3390/s17050985 - 28 Apr 2017

Cited by 9 | Viewed by 3764

Abstract

Array transducer and transducer combination technologies are evolving rapidly. While adapting transmitter combination technologies, the parameter consistencies between each transmitter are extremely important because they can determine a combined effort directly. This study presents a consistency evaluation and calibration method for piezoelectric transmitters [...] Read more.

Array transducer and transducer combination technologies are evolving rapidly. While adapting transmitter combination technologies, the parameter consistencies between each transmitter are extremely important because they can determine a combined effort directly. This study presents a consistency evaluation and calibration method for piezoelectric transmitters by using impedance analyzers. Firstly, electronic parameters of transmitters that can be measured by impedance analyzers are introduced. A variety of transmitter acoustic energies that are caused by these parameter differences are then analyzed and certified and, thereafter, transmitter consistency is evaluated. Lastly, based on the evaluations, consistency can be calibrated by changing the corresponding excitation voltage. Acoustic experiments show that this method accurately evaluates and calibrates transducer consistencies, and is easy to realize. Full article

(This article belongs to the Section Physical Sensors)

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22 pages, 2270 KiB

Open AccessArticle

I3Mote: An Open Development Platform for the Intelligent Industrial Internet

by Borja Martinez^1,*

, Xavier Vilajosana¹

, Il Han Kim², Jianwei Zhou², Pere Tuset-Peiró¹

, Ariton Xhafa², Dominique Poissonnier² and Xiaolin Lu²

¹ Internet Interdisciplinary Institute (IN3), Open University of Catalonia (UOC), Av. Carl Friedrich Gauss, 5, Castelldefels, Barcelona 08860, Spain

² Texas Instruments, Dallas, TX 75243, USA

Sensors 2017, 17(5), 986; https://doi.org/10.3390/s17050986 - 28 Apr 2017

Cited by 37 | Viewed by 7262

Abstract

In this article we present the Intelligent Industrial Internet (I3) Mote, an open hardware platform targeting industrial connectivity and sensing deployments. The I3Mote features the most advanced low-power components to tackle sensing, on-board computing and wireless/wired connectivity for demanding industrial applications. The platform [...] Read more.

In this article we present the Intelligent Industrial Internet (I3) Mote, an open hardware platform targeting industrial connectivity and sensing deployments. The I3Mote features the most advanced low-power components to tackle sensing, on-board computing and wireless/wired connectivity for demanding industrial applications. The platform has been designed to fill the gap in the industrial prototyping and early deployment market with a compact form factor, low-cost and robust industrial design. I3Mote is an advanced and compact prototyping system integrating the required components to be deployed as a product, leveraging the need for adopting industries to build their own tailored solution. This article describes the platform design, firmware and software ecosystem and characterizes its performance in terms of energy consumption. Full article

(This article belongs to the Special Issue Systems and Software for Low Power Embedded Sensing)

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17 pages, 15542 KiB

Open AccessArticle

Sensor Fusion Based on an Integrated Neural Network and Probability Density Function (PDF) Dual Kalman Filter for On-Line Estimation of Vehicle Parameters and States

by Leandro Vargas-Melendez^1,†

, Beatriz L. Boada^1,*,†

, Maria Jesus L. Boada^1,†

, Antonio Gauchia^2,† and Vicente Diaz^1,†

¹ Mechanical Engineering Department, Research Institute of Vehicle Safety, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Madrid, Spain

² Mechanical Engineering-Engineering Mechanics Department, Michigan Tech University, 1400 Townsend Drive, Houghton, MI 49931, USA

^† These authors contributed equally to this work.

Sensors 2017, 17(5), 987; https://doi.org/10.3390/s17050987 - 29 Apr 2017

Cited by 20 | Viewed by 7239

Abstract

Vehicles with a high center of gravity (COG), such as light trucks and heavy vehicles, are prone to rollover. This kind of accident causes nearly

33 %

of all deaths from passenger vehicle crashes. Nowadays, these vehicles are incorporating roll stability control (RSC) [...] Read more.

Vehicles with a high center of gravity (COG), such as light trucks and heavy vehicles, are prone to rollover. This kind of accident causes nearly

33 %

of all deaths from passenger vehicle crashes. Nowadays, these vehicles are incorporating roll stability control (RSC) systems to improve their safety. Most of the RSC systems require the vehicle roll angle as a known input variable to predict the lateral load transfer. The vehicle roll angle can be directly measured by a dual antenna global positioning system (GPS), but it is expensive. For this reason, it is important to estimate the vehicle roll angle from sensors installed onboard in current vehicles. On the other hand, the knowledge of the vehicle’s parameters values is essential to obtain an accurate vehicle response. Some of vehicle parameters cannot be easily obtained and they can vary over time. In this paper, an algorithm for the simultaneous on-line estimation of vehicle’s roll angle and parameters is proposed. This algorithm uses a probability density function (PDF)-based truncation method in combination with a dual Kalman filter (DKF), to guarantee that both vehicle’s states and parameters are within bounds that have a physical meaning, using the information obtained from sensors mounted on vehicles. Experimental results show the effectiveness of the proposed algorithm. Full article

(This article belongs to the Special Issue Sensors for Transportation)

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26 pages, 4626 KiB

Open AccessArticle

An Instrumented Glove to Assess Manual Dexterity in Simulation-Based Neurosurgical Education

by Juan Diego Lemos^1,*, Alher Mauricio Hernandez¹ and Georges Soto-Romero^2,3

¹ Bioinstrumentation and Clinical Engineering Research Group—GIBIC, Bioengineering Department, Engineering Faculty, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín 050010, Colombia

² LAAS-CNRS, Université de Toulouse, CNRS, Toulouse 31400, France

³ ISIFC, Université de Franche-Comté, Besançon 25000, France

Sensors 2017, 17(5), 988; https://doi.org/10.3390/s17050988 - 29 Apr 2017

Cited by 18 | Viewed by 8059

Abstract

The traditional neurosurgical apprenticeship scheme includes the assessment of trainee’s manual skills carried out by experienced surgeons. However, the introduction of surgical simulation technology presents a new paradigm where residents can refine surgical techniques on a simulator before putting them into practice in [...] Read more.

The traditional neurosurgical apprenticeship scheme includes the assessment of trainee’s manual skills carried out by experienced surgeons. However, the introduction of surgical simulation technology presents a new paradigm where residents can refine surgical techniques on a simulator before putting them into practice in real patients. Unfortunately, in this new scheme, an experienced surgeon will not always be available to evaluate trainee’s performance. For this reason, it is necessary to develop automatic mechanisms to estimate metrics for assessing manual dexterity in a quantitative way. Authors have proposed some hardware-software approaches to evaluate manual dexterity on surgical simulators. This paper presents IGlove, a wearable device that uses inertial sensors embedded on an elastic glove to capture hand movements. Metrics to assess manual dexterity are estimated from sensors signals using data processing and information analysis algorithms. It has been designed to be used with a neurosurgical simulator called Daubara NS Trainer, but can be easily adapted to another benchtop- and manikin-based medical simulators. The system was tested with a sample of 14 volunteers who performed a test that was designed to simultaneously evaluate their fine motor skills and the IGlove’s functionalities. Metrics obtained by each of the participants are presented as results in this work; it is also shown how these metrics are used to automatically evaluate the level of manual dexterity of each volunteer. Full article

(This article belongs to the Special Issue Wearable Biomedical Sensors)

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14 pages, 1839 KiB

Open AccessArticle

Analysis of Gamma-Band Activity from Human EEG Using Empirical Mode Decomposition

by Carlos Amo, Luis De Santiago

, Rafael Barea

, Almudena López-Dorado and Luciano Boquete^*

Departamento de Electrónica, Grupo de Ingeniería Biomédica, Universidad de Alcalá, Alcalá de Henares 28801, Spain

Sensors 2017, 17(5), 989; https://doi.org/10.3390/s17050989 - 29 Apr 2017

Cited by 51 | Viewed by 7130

Abstract

The purpose of this paper is to determine whether gamma-band activity detection is improved when a filter, based on empirical mode decomposition (EMD), is added to the pre-processing block of single-channel electroencephalography (EEG) signals. EMD decomposes the original signal into a finite number [...] Read more.

The purpose of this paper is to determine whether gamma-band activity detection is improved when a filter, based on empirical mode decomposition (EMD), is added to the pre-processing block of single-channel electroencephalography (EEG) signals. EMD decomposes the original signal into a finite number of intrinsic mode functions (IMFs). EEGs from 25 control subjects were registered in basal and motor activity (hand movements) using only one EEG channel. Over the basic signal, IMF signals are computed. Gamma-band activity is computed using power spectrum density in the 30–60 Hz range. Event-related synchronization (ERS) was defined as the ratio of motor and basal activity. To evaluate the performance of the new EMD based method, ERS was computed from the basic and IMF signals. The ERS obtained using IMFs improves, from 31.00% to 73.86%, on the original ERS for the right hand, and from 22.17% to 47.69% for the left hand. As EEG processing is improved, the clinical applications of gamma-band activity will expand. Full article

(This article belongs to the Section Biosensors)

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14 pages, 2217 KiB

Open AccessArticle

Using Tri-Axial Accelerometry in Daily Elite Swim Training Practice

by Sander Ganzevles^1,*, Rik Vullings²

, Peter Jan Beek¹

, Hein Daanen¹ and Martin Truijens¹

¹ Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, 1081 BT Amsterdam, The Netherlands

² Faculty of Electrical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands

Sensors 2017, 17(5), 990; https://doi.org/10.3390/s17050990 - 29 Apr 2017

Cited by 24 | Viewed by 6822

Abstract

Background: Coaches in elite swimming carefully design the training programs of their swimmers and are keen on achieving strict adherence to those programs by their athletes. At present, coaches usually monitor the compliance of their swimmers to the training program with a [...] Read more.

Background: Coaches in elite swimming carefully design the training programs of their swimmers and are keen on achieving strict adherence to those programs by their athletes. At present, coaches usually monitor the compliance of their swimmers to the training program with a stopwatch. However, this measurement clearly limits the monitoring possibilities and is subject to human error. Therefore, the present study was designed to examine the reliability and practical usefulness of tri-axial accelerometers for monitoring lap time, stroke count and stroke rate in swimming. Methods: In the first part of the study, a 1200 m warm-up swimming routine was measured in 13 elite swimmers using tri-axial accelerometers and synchronized video recordings. Reliability was determined using the typical error of measurement (TEM) as well as a Bland-Altman analysis. In the second part, training compliance both within and between carefully prescribed training sessions was assessed in four swimmers in order to determine the practical usefulness of the adopted accelerometric approach. In these sessions, targets were set for lap time and stroke count by the coach. Results: The results indicated high reliability for lap time (TEM = 0.26 s, bias = 0.74 [0.56 0.91] with limits of agreement (LoA) from −1.20 [−1.50 −0.90] to 2.70 [2.40 3.00]), stroke count (TEM 0.73 strokes, bias = 0.46 [0.32 0.60] with LoA from −1.70 [−1.94 −1.46] to 2.60 [2.36 2.84]) and stroke rate (TEM 0.72 str∙min⁻¹, bias = −0.13 [−0.20 −0.06] with LoA from −2.20 [−2.32 −2.08] to 1.90 [1.78 2.02]), while the results for the monitoring of training compliance demonstrated the practical usefulness of our approach in daily swimming training. Conclusions: The daily training of elite swimmers can be accurately and reliably monitored using tri-axial accelerometers. They provide the coach with more useful information to guide and control the training process than hand-clocked times. Full article

(This article belongs to the Special Issue Sensors for Ambient Assisted Living, Ubiquitous and Mobile Health)

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13 pages, 12942 KiB

Open AccessArticle

Humidity Sensor Based on Bragg Gratings Developed on the End Facet of an Optical Fiber by Sputtering of One Single Material

by Joaquin Ascorbe^1,*

, Jesus M. Corres²

, Francisco J. Arregui²

and Ignacio R. Matias²

¹ Department of Electrical and Electronic Engineering, Public University of Navarra, Pamplona 31006, Spain

² Institute of Smart Cities, Public University of Navarra, Pamplona 31006, Spain

Sensors 2017, 17(5), 991; https://doi.org/10.3390/s17050991 - 29 Apr 2017

Cited by 19 | Viewed by 5040

Abstract

The refractive index of sputtered indium oxide nanocoatings has been altered just by changing the sputtering parameters, such as pressure. These induced changes have been exploited for the generation of a grating on the end facet of an optical fiber towards the development [...] Read more.

The refractive index of sputtered indium oxide nanocoatings has been altered just by changing the sputtering parameters, such as pressure. These induced changes have been exploited for the generation of a grating on the end facet of an optical fiber towards the development of wavelength-modulated optical fiber humidity sensors. A theoretical analysis has also been performed in order to study the different parameters involved in the fabrication of this optical structure and how they would affect the sensitivity of these devices. Experimental and theoretical results are in good agreement. A sensitivity of 150 pm/%RH was obtained for relative humidity changes from 20% to 60%. This kind of humidity sensors shows a maximum hysteresis of 1.3% relative humidity. Full article

(This article belongs to the Special Issue Humidity Sensors)

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11 pages, 3218 KiB

Open AccessArticle

High Sensitivity Determination of TNF-α for Early Diagnosis of Neonatal Infections with a Novel and Reusable Electrochemical Sensor

by Liangliang Li¹, Miaomiao Li², Wenwen Wang³, Qian Zhang², Dongyun Liu¹, Xianghong Li¹ and Hong Jiang^1,*

¹ Department of Neonatology, The Affiliated Hospital of Qingdao University, Qingdao 266000, China

² Center for Medical Research, The Affiliated Hospital of Qingdao University, Qingdao 266000, China

³ Intensive Care Unit, The Affiliated Hospital of Qingdao University, Qingdao 266000, China

Sensors 2017, 17(5), 992; https://doi.org/10.3390/s17050992 - 10 May 2017

Cited by 13 | Viewed by 5146

Abstract

Early diagnosis is vital for the reduction of mortality caused by neonatal infections. Since TNF-α can be used as a marker for the early diagnosis, the detection of TNF-α with high sensitivity and specificity has great clinical significance. Herein, a highly sensitive and [...] Read more.

Early diagnosis is vital for the reduction of mortality caused by neonatal infections. Since TNF-α can be used as a marker for the early diagnosis, the detection of TNF-α with high sensitivity and specificity has great clinical significance. Herein, a highly sensitive and reusable electrochemical sensor was fabricated. Due to the high specificity of aptamers, TNF-α could be accurately detected from five similar cytokines, even from serum samples. In addition, Au nanoparticles (AuNPs) with a high surface area were able to combine a large number of doxorubicin hydrochloride (DOXh), which made the sensor have a high sensitivity. The sensor had a good linear relationship with TNF-α concentration in the range from 1 to 1 × 10⁴ pg/mL and the lowest detection limit is 0.7 pg/mL. More important was that the sensor could be reused 6 times by a crafty use of chain replacement reaction. Meanwhile, the detection time and cost were greatly reduced. Thus, we believe that these advantages of higher specificity and sensitivity, lower cost, and shorter detection time will provide a stronger potential for early diagnosis of neonatal infections in clinical applications. Full article

(This article belongs to the Section Biosensors)

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10 pages, 3271 KiB

Open AccessArticle

Micro-Doppler Ambiguity Resolution for Wideband Terahertz Radar Using Intra-Pulse Interference

by Qi Yang

, Yuliang Qin^*, Bin Deng, Hongqiang Wang

and Peng You

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

Sensors 2017, 17(5), 993; https://doi.org/10.3390/s17050993 - 29 Apr 2017

Cited by 13 | Viewed by 5168

Abstract

Micro-Doppler, induced by micro-motion of targets, is an important characteristic of target recognition once extracted via parameter estimation methods. However, micro-Doppler is usually too significant to result in ambiguity in the terahertz band because of its relatively high carrier frequency. Thus, a micro-Doppler [...] Read more.

Micro-Doppler, induced by micro-motion of targets, is an important characteristic of target recognition once extracted via parameter estimation methods. However, micro-Doppler is usually too significant to result in ambiguity in the terahertz band because of its relatively high carrier frequency. Thus, a micro-Doppler ambiguity resolution method for wideband terahertz radar using intra-pulse interference is proposed in this paper. The micro-Doppler can be reduced several dozen times its true value to avoid ambiguity through intra-pulse interference processing. The effectiveness of this method is proved by experiments based on a 0.22 THz wideband radar system, and its high estimation precision and excellent noise immunity are verified by Monte Carlo simulation. Full article

(This article belongs to the Section Remote Sensors)

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18 pages, 541 KiB

Open AccessArticle

Scalability Issues for Remote Sensing Infrastructure: A Case Study

by Yang Liu, Sean Picard and Carey Williamson^*,†

¹ Department of Computer Science, University of Calgary, Calgary, AB T2N 1N4, Canada

^† Current address: 2500 University Drive NW, Calgary, AB T2N 1N4, Canada

Sensors 2017, 17(5), 994; https://doi.org/10.3390/s17050994 - 29 Apr 2017

Cited by 2 | Viewed by 4905

Abstract

For the past decade, a team of University of Calgary researchers has operated a large “sensor Web” to collect, analyze, and share scientific data from remote measurement instruments across northern Canada. This sensor Web receives real-time data streams from over a thousand Internet-connected [...] Read more.

For the past decade, a team of University of Calgary researchers has operated a large “sensor Web” to collect, analyze, and share scientific data from remote measurement instruments across northern Canada. This sensor Web receives real-time data streams from over a thousand Internet-connected sensors, with a particular emphasis on environmental data (e.g., space weather, auroral phenomena, atmospheric imaging). Through research collaborations, we had the opportunity to evaluate the performance and scalability of their remote sensing infrastructure. This article reports the lessons learned from our study, which considered both data collection and data dissemination aspects of their system. On the data collection front, we used benchmarking techniques to identify and fix a performance bottleneck in the system’s memory management for TCP data streams, while also improving system efficiency on multi-core architectures. On the data dissemination front, we used passive and active network traffic measurements to identify and reduce excessive network traffic from the Web robots and JavaScript techniques used for data sharing. While our results are from one specific sensor Web system, the lessons learned may apply to other scientific Web sites with remote sensing infrastructure. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Canada 2017)

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20 pages, 10320 KiB

Open AccessArticle

A Lever Coupling Mechanism in Dual-Mass Micro-Gyroscopes for Improving the Shock Resistance along the Driving Direction

by Yang Gao^1,2

, Hongsheng Li^1,2,*, Libin Huang^1,2 and Hui Sun^1,2

¹ School of Instrument Science and Engineering, Southeast University, Nanjing 210096, China

² Key Laboratory of Micro-Inertial Instruments and Advanced Navigation Technology, Ministry of Education, Nanjing 210096, China

Sensors 2017, 17(5), 995; https://doi.org/10.3390/s17050995 - 30 Apr 2017

Cited by 13 | Viewed by 4614

Abstract

This paper presents the design and application of a lever coupling mechanism to improve the shock resistance of a dual-mass silicon micro-gyroscope with drive mode coupled along the driving direction without sacrificing the mechanical sensitivity. Firstly, the mechanical sensitivity and the shock response [...] Read more.

This paper presents the design and application of a lever coupling mechanism to improve the shock resistance of a dual-mass silicon micro-gyroscope with drive mode coupled along the driving direction without sacrificing the mechanical sensitivity. Firstly, the mechanical sensitivity and the shock response of the micro-gyroscope are theoretically analyzed. In the mechanical design, a novel lever coupling mechanism is proposed to change the modal order and to improve the frequency separation. The micro-gyroscope with the lever coupling mechanism optimizes the drive mode order, increasing the in-phase mode frequency to be much larger than the anti-phase one. Shock analysis results show that the micro-gyroscope structure with the designed lever coupling mechanism can notably reduce the magnitudes of the shock response and cut down the stress produced in the shock process compared with the traditional elastic coupled one. Simulations reveal that the shock resistance along the drive direction is greatly increased. Consequently, the lever coupling mechanism can change the gyroscope’s modal order and improve the frequency separation by structurally offering a higher stiffness difference ratio. The shock resistance along the driving direction is tremendously enhanced without loss of the mechanical sensitivity. Full article

(This article belongs to the Section Physical Sensors)

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17 pages, 522 KiB

Open AccessArticle

Canoe: An Autonomous Infrastructure-Free Indoor Navigation System

by Kai Dong^1,*, Wenjia Wu¹, Haibo Ye², Ming Yang¹, Zhen Ling¹ and Wei Yu³

¹ School of Computer Science and Engineering, Southeast University, Nangjing 211189, China

² College of Computer Science and Technology, Nanjing University of Aeronautics and Astronautics, Nangjing 210016, China

³ Department of Computer and Information Sciences, Towson University, Towson MD 21252, USA

Sensors 2017, 17(5), 996; https://doi.org/10.3390/s17050996 - 30 Apr 2017

Cited by 11 | Viewed by 4716

Abstract

The development of the Internet of Things (IoT) has accelerated research in indoor navigation systems, a majority of which rely on adequate wireless signals and sources. Nonetheless, deploying such a system requires periodic site-survey, which is time consuming and labor intensive. To address [...] Read more.

The development of the Internet of Things (IoT) has accelerated research in indoor navigation systems, a majority of which rely on adequate wireless signals and sources. Nonetheless, deploying such a system requires periodic site-survey, which is time consuming and labor intensive. To address this issue, in this paper we present Canoe, an indoor navigation system that considers shopping mall scenarios. In our system, we do not assume any prior knowledge, such as floor-plan or the shop locations, access point placement or power settings, historical RSS measurements or fingerprints, etc. Instead, Canoe requires only that the shop owners collect and publish RSS values at the entrances of their shops and can direct a consumer to any of these shops by comparing the observed RSS values. The locations of the consumers and the shops are estimated using maximum likelihood estimation. In doing this, the direction of the target shop relative to the current orientation of the consumer can be precisely computed, such that the direction that a consumer should move can be determined. We have conducted extensive simulations using a real-world dataset. Our experiments in a real shopping mall demonstrate that if 50% of the shops publish their RSS values, Canoe can precisely navigate a consumer within 30 s, with an error rate below 9%. Full article

(This article belongs to the Special Issue New Advances in Identification, Information & Knowledge in the Internet of Things)

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16 pages, 1887 KiB

Open AccessArticle

Bluetooth Low Power Modes Applied to the Data Transportation Network in Home Automation Systems

by Josu Etxaniz^*

and Gerardo Aranguren

Electronic Technology Department, University of the Basque Country, Bilbao 48980, Spain

Sensors 2017, 17(5), 997; https://doi.org/10.3390/s17050997 - 30 Apr 2017

Cited by 4 | Viewed by 4648

Abstract

Even though home automation is a well-known research and development area, recent technological improvements in different areas such as context recognition, sensing, wireless communications or embedded systems have boosted wireless smart homes. This paper focuses on some of those areas related to home [...] Read more.

Even though home automation is a well-known research and development area, recent technological improvements in different areas such as context recognition, sensing, wireless communications or embedded systems have boosted wireless smart homes. This paper focuses on some of those areas related to home automation. The paper draws attention to wireless communications issues on embedded systems. Specifically, the paper discusses the multi-hop networking together with Bluetooth technology and latency, as a quality of service (QoS) metric. Bluetooth is a worldwide standard that provides low power multi-hop networking. It is a radio license free technology and establishes point-to-point and point-to-multipoint links, known as piconets, or multi-hop networks, known as scatternets. This way, many Bluetooth nodes can be interconnected to deploy ambient intelligent networks. This paper introduces the research on multi-hop latency done with park and sniff low power modes of Bluetooth over the test platform developed. Besides, an empirical model is obtained to calculate the latency of Bluetooth multi-hop communications over asynchronous links when links in scatternets are always in sniff or the park mode. Smart home devices and networks designers would take advantage of the models and the estimation of the delay they provide in communications along Bluetooth multi-hop networks. Full article

(This article belongs to the Special Issue Sensors for Home Automation and Security)

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15 pages, 5266 KiB

Open AccessArticle

DCE: A Distributed Energy-Efficient Clustering Protocol for Wireless Sensor Network Based on Double-Phase Cluster-Head Election

by Ruisong Han

, Wei Yang^*, Yipeng Wang and Kaiming You

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

Sensors 2017, 17(5), 998; https://doi.org/10.3390/s17050998 - 1 May 2017

Cited by 45 | Viewed by 7882

Abstract

Clustering is an effective technique used to reduce energy consumption and extend the lifetime of wireless sensor network (WSN). The characteristic of energy heterogeneity of WSNs should be considered when designing clustering protocols. We propose and evaluate a novel distributed energy-eﬃcient clustering protocol [...] Read more.

Clustering is an effective technique used to reduce energy consumption and extend the lifetime of wireless sensor network (WSN). The characteristic of energy heterogeneity of WSNs should be considered when designing clustering protocols. We propose and evaluate a novel distributed energy-eﬃcient clustering protocol called DCE for heterogeneous wireless sensor networks, based on a Double-phase Cluster-head Election scheme. In DCE, the procedure of cluster head election is divided into two phases. In the first phase, tentative cluster heads are elected with the probabilities which are decided by the relative levels of initial and residual energy. Then, in the second phase, the tentative cluster heads are replaced by their cluster members to form the final set of cluster heads if any member in their cluster has more residual energy. Employing two phases for cluster-head election ensures that the nodes with more energy have a higher chance to be cluster heads. Energy consumption is well-distributed in the proposed protocol, and the simulation results show that DCE achieves longer stability periods than other typical clustering protocols in heterogeneous scenarios. Full article

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

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28 pages, 1500 KiB

Open AccessArticle

Designing Waveform Sets with Good Correlation and Stopband Properties for MIMO Radar via the Gradient-Based Method

by Liang Tang^*

, Yongfeng Zhu and Qiang Fu

College of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073,

Sensors 2017, 17(5), 999; https://doi.org/10.3390/s17050999 - 1 May 2017

Cited by 13 | Viewed by 4646

Abstract

Waveform sets with good correlation and/or stopband properties have received extensive attention and been widely used in multiple-input multiple-output (MIMO) radar. In this paper, we aim at designing unimodular waveform sets with good correlation and stopband properties. To formulate the problem, we construct [...] Read more.

Waveform sets with good correlation and/or stopband properties have received extensive attention and been widely used in multiple-input multiple-output (MIMO) radar. In this paper, we aim at designing unimodular waveform sets with good correlation and stopband properties. To formulate the problem, we construct two criteria to measure the correlation and stopband properties and then establish an unconstrained problem in the frequency domain. After deducing the phase gradient and the step size, an efficient gradient-based algorithm with monotonicity is proposed to minimize the objective function directly. For the design problem without considering the correlation weights, we develop a simplified algorithm, which only requires a few fast Fourier transform (FFT) operations and is more efficient. Because both of the algorithms can be implemented via the FFT operations and the Hadamard product, they are computationally efficient and can be used to design waveform sets with a large waveform number and waveform length. Numerical experiments show that the proposed algorithms can provide better performance than the state-of-the-art algorithms in terms of the computational complexity. Full article

(This article belongs to the Section Remote Sensors)

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17 pages, 1011 KiB

Open AccessArticle

A Novel Certificateless Signature Scheme for Smart Objects in the Internet-of-Things

by Kuo-Hui Yeh¹

, Chunhua Su^2,*, Kim-Kwang Raymond Choo³ and Wayne Chiu¹

¹ Department of Information Management, National Dong Hwa University, Hualien 97401, Taiwan

² Division of Computer Science, University of Aizu, Aizu-Wakamatsu, Fukushima Pref. 965-8580, Japan

³ Department of Information Systems and Cyber Security, The University of Texas at San Antonio, San Antonio, TX 78249, USA

Sensors 2017, 17(5), 1001; https://doi.org/10.3390/s17051001 - 1 May 2017

Cited by 72 | Viewed by 7450

Abstract

Rapid advances in wireless communications and pervasive computing technologies have resulted in increasing interest and popularity of Internet-of-Things (IoT) architecture, ubiquitously providing intelligence and convenience to our daily life. In IoT-based network environments, smart objects are embedded everywhere as ubiquitous things connected in [...] Read more.

Rapid advances in wireless communications and pervasive computing technologies have resulted in increasing interest and popularity of Internet-of-Things (IoT) architecture, ubiquitously providing intelligence and convenience to our daily life. In IoT-based network environments, smart objects are embedded everywhere as ubiquitous things connected in a pervasive manner. Ensuring security for interactions between these smart things is significantly more important, and a topic of ongoing interest. In this paper, we present a certificateless signature scheme for smart objects in IoT-based pervasive computing environments. We evaluate the utility of the proposed scheme in IoT-oriented testbeds, i.e., Arduino Uno and Raspberry PI 2. Experiment results present the practicability of the proposed scheme. Moreover, we revisit the scheme of Wang et al. (2015) and revealed that a malicious super type I adversary can easily forge a legitimate signature to cheat any receiver as he/she wishes in the scheme. The superiority of the proposed certificateless signature scheme over relevant studies is demonstrated in terms of the summarized security and performance comparisons. Full article

(This article belongs to the Special Issue New Generation Sensors Enabling and Fostering IoT)

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18 pages, 3457 KiB

Open AccessArticle

An Acceleration-Based Gait Assessment Method for Children with Cerebral Palsy

by Xiang Chen^1,*, Songmei Liao¹, Shuai Cao¹

, De Wu² and Xu Zhang¹

¹ Department of Electronic Science and Technology, University of Science and Technology of China, Hefei 230026, China

² Department of Pediatrics, The First Affiliated Hospital of Anhui Medical University, Hefei 230026, China

Sensors 2017, 17(5), 1002; https://doi.org/10.3390/s17051002 - 2 May 2017

Cited by 15 | Viewed by 5798

Abstract

With the aim of providing an objective tool for motion disability assessment in clinical diagnosis and rehabilitation therapy of cerebral palsy (CP) patients, an acceleration-based gait assessment method was proposed in this paper. To capture gait information, three inertial measurement units (IMUs) were [...] Read more.

With the aim of providing an objective tool for motion disability assessment in clinical diagnosis and rehabilitation therapy of cerebral palsy (CP) patients, an acceleration-based gait assessment method was proposed in this paper. To capture gait information, three inertial measurement units (IMUs) were placed on the lower trunk and thigh, respectively. By comparing differences in the gait acceleration modes between children with CP and healthy subjects, an assessment method based on grey relational analysis and five gait parameters, including Pearson coefficient, variance ratio, the number of extreme points, harmonic ratio and symmetry was established. Twenty-two children with cerebral palsy (7.49 ± 2.86 years old), fourteen healthy adults (24.2 ± 1.55 years old) and ten healthy children (7.03 ± 1.49 years old) participated in the gait data acquisition experiment. The results demonstrated that, compared to healthy subjects, the symptoms and severity of motor dysfunction of CP children could result in abnormality of the gait acceleration modes, and the proposed assessment method was able to effectively evaluate the degree gait abnormality in CP children. Full article

(This article belongs to the Section Physical Sensors)

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19 pages, 1522 KiB

Open AccessArticle

OpenSHS: Open Smart Home Simulator

by Nasser Alshammari^1,2,*

, Talal Alshammari^1,3

, Mohamed Sedky¹

, Justin Champion¹ and Carolin Bauer¹

¹ Staffordshire University, College Road, ST4 2DE Stoke-on-Trent, UK

² College of Information and Computer Science, Aljouf University, Sakaka 72388, Saudi Arabia

³ College of Computer Science and Engineering, University of Hail, Hail 53962, Saudi Arabia

Sensors 2017, 17(5), 1003; https://doi.org/10.3390/s17051003 - 2 May 2017

Cited by 66 | Viewed by 13293

Abstract

This paper develops a new hybrid, open-source, cross-platform 3D smart home simulator, OpenSHS, for dataset generation. OpenSHS offers an opportunity for researchers in the field of the Internet of Things (IoT) and machine learning to test and evaluate their models. Following a hybrid [...] Read more.

This paper develops a new hybrid, open-source, cross-platform 3D smart home simulator, OpenSHS, for dataset generation. OpenSHS offers an opportunity for researchers in the field of the Internet of Things (IoT) and machine learning to test and evaluate their models. Following a hybrid approach, OpenSHS combines advantages from both interactive and model-based approaches. This approach reduces the time and efforts required to generate simulated smart home datasets. We have designed a replication algorithm for extending and expanding a dataset. A small sample dataset produced, by OpenSHS, can be extended without affecting the logical order of the events. The replication provides a solution for generating large representative smart home datasets. We have built an extensible library of smart devices that facilitates the simulation of current and future smart home environments. Our tool divides the dataset generation process into three distinct phases: first design: the researcher designs the initial virtual environment by building the home, importing smart devices and creating contexts; second, simulation: the participant simulates his/her context-specific events; and third, aggregation: the researcher applies the replication algorithm to generate the final dataset. We conducted a study to assess the ease of use of our tool on the System Usability Scale (SUS). Full article

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

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15 pages, 23994 KiB

Open AccessArticle

Finite Element Analysis of Film Stack Architecture for Complementary Metal-Oxide–Semiconductor Image Sensors

by Kuo-Tsai Wu¹, Sheng-Jye Hwang^1,* and Huei-Huang Lee²

¹ Department of Mechanical Engineering, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan

² Department of Engineering Science, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan

Sensors 2017, 17(5), 1004; https://doi.org/10.3390/s17051004 - 2 May 2017

Cited by 6 | Viewed by 8329

Abstract

Image sensors are the core components of computer, communication, and consumer electronic products. Complementary metal oxide semiconductor (CMOS) image sensors have become the mainstay of image-sensing developments, but are prone to leakage current. In this study, we simulate the CMOS image sensor (CIS) [...] Read more.

Image sensors are the core components of computer, communication, and consumer electronic products. Complementary metal oxide semiconductor (CMOS) image sensors have become the mainstay of image-sensing developments, but are prone to leakage current. In this study, we simulate the CMOS image sensor (CIS) film stacking process by finite element analysis. To elucidate the relationship between the leakage current and stack architecture, we compare the simulated and measured leakage currents in the elements. Based on the analysis results, we further improve the performance by optimizing the architecture of the film stacks or changing the thin-film material. The material parameters are then corrected to improve the accuracy of the simulation results. The simulated and experimental results confirm a positive correlation between measured leakage current and stress. This trend is attributed to the structural defects induced by high stress, which generate leakage. Using this relationship, we can change the structure of the thin-film stack to reduce the leakage current and thereby improve the component life and reliability of the CIS components. Full article

(This article belongs to the Special Issue MEMS and Nano-Sensors)

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14 pages, 4700 KiB

Open AccessArticle

High Precision Temperature Insensitive Strain Sensor Based on Fiber-Optic Delay

by Ning Yang, Jun Su^*, Zhiqiang Fan and Qi Qiu

School of OptoElectronic information, University of Electronic Science and Technology of China, Chengdu 610054, China

Sensors 2017, 17(5), 1005; https://doi.org/10.3390/s17051005 - 2 May 2017

Cited by 11 | Viewed by 5285

Abstract

A fiber-optic delay based strain sensor with high precision and temperature insensitivity was reported, which works on detecting the delay induced by strain instead of spectrum. In order to analyze the working principle of this sensor, the elastic property of fiber-optic delay was [...] Read more.

A fiber-optic delay based strain sensor with high precision and temperature insensitivity was reported, which works on detecting the delay induced by strain instead of spectrum. In order to analyze the working principle of this sensor, the elastic property of fiber-optic delay was theoretically researched and the elastic coefficient was measured as 3.78 ps/km·με. In this sensor, an extra reference path was introduced to simplify the measurement of delay and resist the cross-effect of environmental temperature. Utilizing an optical fiber stretcher driven by piezoelectric ceramics, the performance of this strain sensor was tested. The experimental results demonstrate that temperature fluctuations contribute little to the strain error and that the calculated strain sensitivity is as high as 4.75 με in the range of 350 με. As a result, this strain sensor is proved to be feasible and practical, which is appropriate for strain measurement in a simple and economical way. Furthermore, on basis of this sensor, the quasi-distributed measurement could be also easily realized by wavelength division multiplexing and wavelength addressing for long-distance structure health and security monitoring. Full article

(This article belongs to the Section Physical Sensors)

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16 pages, 3665 KiB

Open AccessArticle

Support System to Improve Reading Activity in Parkinson’s Disease and Essential Tremor Patients

by Franklin Parrales Bravo^1,*

, Alberto A. Del Barrio García¹

, Mercedes Gallego de la Sacristana², Lydia López Manzanares², José Vivancos² and José Luis Ayala Rodrigo¹

¹ Faculty of Computer Science, Complutense University of Madrid, Av. Séneca, 2, 28040 Madrid, Spain

² Neurology Department, “La Princesa” University Hospital, Calle de Diego Leon, 62, 28006 Madrid, Spain

Sensors 2017, 17(5), 1006; https://doi.org/10.3390/s17051006 - 3 May 2017

Cited by 9 | Viewed by 5123

Abstract

The use of information and communication technologies (ICTs) to improve the quality of life of people with chronic and degenerative diseases is a topic receiving much attention nowadays. We can observe that new technologies have driven numerous scientific projects in e-Health, encompassing Smart [...] Read more.

The use of information and communication technologies (ICTs) to improve the quality of life of people with chronic and degenerative diseases is a topic receiving much attention nowadays. We can observe that new technologies have driven numerous scientific projects in e-Health, encompassing Smart and Mobile Health, in order to address all the matters related to data processing and health. Our work focuses on helping to improve the quality of life of people with Parkinson’s Disease (PD) and Essential Tremor (ET) by means of a low-cost platform that enables them to read books in an easy manner. Our system is composed of two robotic arms and a graphical interface developed for Android platforms. After several tests, our proposal has achieved a 96.5% accuracy for A4 80 gr non-glossy paper. Moreover, our system has outperformed the state-of-the-art platforms considering different types of paper and inclined surfaces. The feedback from ET and PD patients was collected at “La Princesa” University Hospital in Madrid and was used to study the user experience. Several features such as ease of use, speed, correct behavior or confidence were measured via patient feedback, and a high level of satisfaction was awarded to most of them. According to the patients, our system is a promising tool for facilitating the activity of reading. Full article

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

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16 pages, 1551 KiB

Open AccessArticle

A Framework for the Multi-Level Fusion of Electronic Nose and Electronic Tongue for Tea Quality Assessment

by Ruicong Zhi^1,2,*, Lei Zhao³ and Dezheng Zhang^1,2

¹ School of Computer and Communication Engineering, University of Science and Technology Beijing, Beijing 100083, China

² Beijing Key Laboratory of Knowledge Engineering for Materials Science, Beijing 100083, China

³ China National Institute of Standardization, Beijing 100191, China

Sensors 2017, 17(5), 1007; https://doi.org/10.3390/s17051007 - 3 May 2017

Cited by 88 | Viewed by 7351

Abstract

Electronic nose (E-nose) and electronic tongue (E-tongue) can mimic the sensory perception of human smell and taste, and they are widely applied in tea quality evaluation by utilizing the fingerprints of response signals representing the overall information of tea samples. The intrinsic part [...] Read more.

Electronic nose (E-nose) and electronic tongue (E-tongue) can mimic the sensory perception of human smell and taste, and they are widely applied in tea quality evaluation by utilizing the fingerprints of response signals representing the overall information of tea samples. The intrinsic part of human perception is the fusion of sensors, as more information is provided comparing to the information from a single sensory organ. In this study, a framework for a multi-level fusion strategy of electronic nose and electronic tongue was proposed to enhance the tea quality prediction accuracies, by simultaneously modeling feature fusion and decision fusion. The procedure included feature-level fusion (fuse the time-domain based feature and frequency-domain based feature) and decision-level fusion (D-S evidence to combine the classification results from multiple classifiers). The experiments were conducted on tea samples collected from various tea providers with four grades. The large quantity made the quality assessment task very difficult, and the experimental results showed much better classification ability for the multi-level fusion system. The proposed algorithm could better represent the overall characteristics of tea samples for both odor and taste. Full article

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

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11 pages, 10223 KiB

Open AccessArticle

A Capacitive Humidity Sensor Based on an Electrospun PVDF/Graphene Membrane

by Daniel Hernández-Rivera, Grissel Rodríguez-Roldán, Rodrigo Mora-Martínez and Ernesto Suaste-Gómez^*

Electrical Engineering Department, Bioelectronics Section, Centro de Investigación y de Estudios Avanzados del IPN, Av. IPN 2508, Col. San Pedro Zacatenco, Mexico City 07360, Mexico

Sensors 2017, 17(5), 1009; https://doi.org/10.3390/s17051009 - 3 May 2017

Cited by 83 | Viewed by 10776

Abstract

Humidity sensors have been widely used in areas such as agriculture, environmental conservation, medicine, instrumentation and climatology. Hydrophobicity is one of the important factors in capacitive humidity sensors: recent research has shown that the inclusion of graphene (G) in polyvinylidene fluoride (PVDF) improves [...] Read more.

Humidity sensors have been widely used in areas such as agriculture, environmental conservation, medicine, instrumentation and climatology. Hydrophobicity is one of the important factors in capacitive humidity sensors: recent research has shown that the inclusion of graphene (G) in polyvinylidene fluoride (PVDF) improves its hydrophobicity. In this context, a methodology to fabricate electrospun membranes of PVDF blended with G was developed in order to improve the PVDF properties allowing the use of PVDF/G membrane as a capacitive humidity sensor. Micrographs of membranes were obtained by scanning electron microscopy to analyze the morphology of the fabricated samples. Subsequently, the capacitive response of the membrane, which showed an almost linear and directly proportional response to humidity, was tested. Results showed that the response time of PVDF/G membrane was faster than that of a commercial DHT11 sensor. In summary, PVDF/G membranes exhibit interesting properties as humidity sensors. Full article

(This article belongs to the Special Issue Humidity Sensors)

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24 pages, 20584 KiB

Open AccessArticle

A Study of the CO Sensing Responses of Cu-, Pt- and Pd-Activated SnO₂ Sensors: Effect of Precipitation Agents, Dopants and Doping Methods

by Venkata Krishna Karthik Tangirala^1,*

, Heberto Gómez-Pozos², Ventura Rodríguez-Lugo³ and María De La Luz Olvera¹

¹ Departamento de Ingeniería Eléctrica-SEES, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, CINVESTAV-IPN, Apartado postal 14740, México D. F. 07360, Mexico

² Área Académica de Computación y Electrónica, ICBI, Universidad Autónoma del Estado de Hidalgo, Hidalgo 56092, Mexico

³ Área Académica de Ciencias de la Tierra y Materiales, Instituto de Ciencias Básicas e Ingeniería, Universidad Autónoma del Estado de Hidalgo, Carretera Pachuca-Tulancingo Km. 4.5, Hidalgo 42184, Mexico

Sensors 2017, 17(5), 1011; https://doi.org/10.3390/s17051011 - 3 May 2017

Cited by 36 | Viewed by 7227

Abstract

In this work, we report the synthesis of Cu, Pt and Pd doped SnO₂ powders and a comparative study of their CO gas sensing performance. Dopants were incorporated into SnO₂ nanostructures using chemical and impregnation methods by using urea and ammonia [...] Read more.

In this work, we report the synthesis of Cu, Pt and Pd doped SnO₂ powders and a comparative study of their CO gas sensing performance. Dopants were incorporated into SnO₂ nanostructures using chemical and impregnation methods by using urea and ammonia as precipitation agents. The synthesized samples were characterized using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HR-TEM). The presence of dopants within the SnO₂ nanostructures was evidenced from the HR-TEM results. Powders doped utilizing chemical methods with urea as precipitation agent presented higher sensing responses compared to the other forms, which is due to the formation of uniform and homogeneous particles resulting from the temperature-assisted synthesis. The particle sizes of doped SnO₂ nanostructures were in the range of 40–100 nm. An enhanced sensing response around 1783 was achieved with Cu-doped SnO₂ when compared with two other dopants i.e., Pt (1200) and Pd:SnO₂ (502). The high sensing response of Cu:SnO₂ is due to formation of CuO and its excellent association and dissociation with adsorbed atmospheric oxygen in the presence of CO at the sensor operation temperature, which results in high conductance. Cu:SnO₂ may thus be an alternative and cost effective sensor for industrial applications. Full article

(This article belongs to the Collection Gas Sensors)

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16 pages, 395 KiB

Open AccessArticle

Social Welfare Control in Mobile Crowdsensing Using Zero-Determinant Strategy

by Qin Hu¹, Shengling Wang^1,*, Rongfang Bie¹ and Xiuzhen Cheng²

¹ College of Information Science and Technology, Beijing Normal University, Beijing 100875, China

² Department of Computer Science, George Washington University, Washington, DC 20052, USA

Sensors 2017, 17(5), 1012; https://doi.org/10.3390/s17051012 - 3 May 2017

Cited by 11 | Viewed by 3806

Abstract

As a promising paradigm, mobile crowdsensing exerts the potential of widespread sensors embedded in mobile devices. The greedy nature of workers brings the problem of low-quality sensing data, which poses threats to the overall performance of a crowdsensing system. Existing works often tackle [...] Read more.

As a promising paradigm, mobile crowdsensing exerts the potential of widespread sensors embedded in mobile devices. The greedy nature of workers brings the problem of low-quality sensing data, which poses threats to the overall performance of a crowdsensing system. Existing works often tackle this problem with additional function components. In this paper, we systematically formulate the problem into a crowdsensing interaction process between a requestor and a worker, which can be modeled by two types of iterated games with different strategy spaces. Considering that the low-quality data submitted by the workers can reduce the requestor’s payoff and further decrease the global income, we turn to controlling the social welfare in the games. To that aim, we take advantage of zero-determinant strategy, based on which we propose two social welfare control mechanisms under both game models. Specifically, we consider the requestor as the controller of the games and, with proper parameter settings for the to-be-adopted zero-determinant strategy, social welfare can be optimized to the desired level no matter what strategy the worker adopts. Simulation results demonstrate that the requestor can achieve the maximized social welfare and keep it stable by using our proposed mechanisms. Full article

(This article belongs to the Special Issue New Advances in Identification, Information & Knowledge in the Internet of Things)

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17 pages, 3681 KiB

Open AccessArticle

Distributed and Modular CAN-Based Architecture for Hardware Control and Sensor Data Integration

by Diego P. Losada^1,*, Joaquín L. Fernández², Enrique Paz² and Rafael Sanz²

¹ Robotics and Control Unit, AIMEN Technology Centre, Porriño 36410, Spain

² Department of System Engineering and Automation, University of Vigo, Vigo 36310, Spain

Sensors 2017, 17(5), 1013; https://doi.org/10.3390/s17051013 - 3 May 2017

Cited by 12 | Viewed by 6981

Abstract

In this article, we present a CAN-based (Controller Area Network) distributed system to integrate sensors, actuators and hardware controllers in a mobile robot platform. With this work, we provide a robust, simple, flexible and open system to make hardware elements or subsystems communicate, [...] Read more.

In this article, we present a CAN-based (Controller Area Network) distributed system to integrate sensors, actuators and hardware controllers in a mobile robot platform. With this work, we provide a robust, simple, flexible and open system to make hardware elements or subsystems communicate, that can be applied to different robots or mobile platforms. Hardware modules can be connected to or disconnected from the CAN bus while the system is working. It has been tested in our mobile robot Rato, based on a RWI (Real World Interface) mobile platform, to replace the old sensor and motor controllers. It has also been used in the design of two new robots: BellBot and WatchBot. Currently, our hardware integration architecture supports different sensors, actuators and control subsystems, such as motor controllers and inertial measurement units. The integration architecture was tested and compared with other solutions through a performance analysis of relevant parameters such as transmission efficiency and bandwidth usage. The results conclude that the proposed solution implements a lightweight communication protocol for mobile robot applications that avoids transmission delays and overhead. Full article

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

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21 pages, 941 KiB

Open AccessArticle

A Fast, Efficient Domain Adaptation Technique for Cross-Domain Electroencephalography(EEG)-Based Emotion Recognition

by Xin Chai¹, Qisong Wang^1,*, Yongping Zhao¹, Yongqiang Li¹, Dan Liu¹, Xin Liu² and Ou Bai³

¹ School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin 150001, China

² Department of Traffic Information and Control Engineering, School of Transportation Science and Engineering, Harbin Institute of Technology, Harbin 150001, China

³ Department of Electrical and Computer Engineering, Florida International University, Miami, FL 33199, USA

Sensors 2017, 17(5), 1014; https://doi.org/10.3390/s17051014 - 3 May 2017

Cited by 108 | Viewed by 8446

Abstract

Electroencephalography (EEG)-based emotion recognition is an important element in psychiatric health diagnosis for patients. However, the underlying EEG sensor signals are always non-stationary if they are sampled from different experimental sessions or subjects. This results in the deterioration of the classification performance. Domain [...] Read more.

Electroencephalography (EEG)-based emotion recognition is an important element in psychiatric health diagnosis for patients. However, the underlying EEG sensor signals are always non-stationary if they are sampled from different experimental sessions or subjects. This results in the deterioration of the classification performance. Domain adaptation methods offer an effective way to reduce the discrepancy of marginal distribution. However, for EEG sensor signals, both marginal and conditional distributions may be mismatched. In addition, the existing domain adaptation strategies always require a high level of additional computation. To address this problem, a novel strategy named adaptive subspace feature matching (ASFM) is proposed in this paper in order to integrate both the marginal and conditional distributions within a unified framework (without any labeled samples from target subjects). Specifically, we develop a linear transformation function which matches the marginal distributions of the source and target subspaces without a regularization term. This significantly decreases the time complexity of our domain adaptation procedure. As a result, both marginal and conditional distribution discrepancies between the source domain and unlabeled target domain can be reduced, and logistic regression (LR) can be applied to the new source domain in order to train a classifier for use in the target domain, since the aligned source domain follows a distribution which is similar to that of the target domain. We compare our ASFM method with six typical approaches using a public EEG dataset with three affective states: positive, neutral, and negative. Both offline and online evaluations were performed. The subject-to-subject offline experimental results demonstrate that our component achieves a mean accuracy and standard deviation of 80.46% and 6.84%, respectively, as compared with a state-of-the-art method, the subspace alignment auto-encoder (SAAE), which achieves values of 77.88% and 7.33% on average, respectively. For the online analysis, the average classification accuracy and standard deviation of ASFM in the subject-to-subject evaluation for all the 15 subjects in a dataset was 75.11% and 7.65%, respectively, gaining a significant performance improvement compared to the best baseline LR which achieves 56.38% and 7.48%, respectively. The experimental results confirm the effectiveness of the proposed method relative to state-of-the-art methods. Moreover, computational efficiency of the proposed ASFM method is much better than standard domain adaptation; if the numbers of training samples and test samples are controlled within certain range, it is suitable for real-time classification. It can be concluded that ASFM is a useful and effective tool for decreasing domain discrepancy and reducing performance degradation across subjects and sessions in the field of EEG-based emotion recognition. Full article

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

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12 pages, 3728 KiB

Open AccessArticle

ZnO Film Bulk Acoustic Resonator for the Kinetics Study of Human Blood Coagulation

by Da Chen^*, Zhen Zhang, Jilong Ma and Wei Wang

State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology, College of Electronics, Communications, and Physics, Shandong University of Science and Technology, Qingdao 266590, China

Sensors 2017, 17(5), 1015; https://doi.org/10.3390/s17051015 - 3 May 2017

Cited by 24 | Viewed by 6381

Abstract

Miniaturized and rapid blood coagulation assay technologies are critical in many clinical settings. In this paper, we present a ZnO film bulk acoustic resonator for the kinetic analysis of human blood coagulation. The resonator operated in thickness shear resonance mode at 1.4 GHz. [...] Read more.

Miniaturized and rapid blood coagulation assay technologies are critical in many clinical settings. In this paper, we present a ZnO film bulk acoustic resonator for the kinetic analysis of human blood coagulation. The resonator operated in thickness shear resonance mode at 1.4 GHz. When the resonator contacted the liquid environment, the viscous loading effect was considered as the additional resistance and inductance in the equivalent circuits, resulting in a linear relationship with a slope of approximately −217 kHz/cP between the liquid viscosity and the frequency of the resonator. The downshift of the resonant frequency and the viscosity change during the blood coagulation were correlated to monitor the coagulation process. The sigmoidal trend was observed in the frequency response for the blood samples activated by thromboplastin and calcium ions. The coagulation kinetics involving sequential phases of steady reaction, growth and saturation were revealed through the time-dependent frequency profiles. The enzymatic cascade time, the coagulation rate, the coagulation time and the clot degree were provided by fitting the time-frequency curves. The prothrombin times were compared with the results measured by a standard coagulometer and show a good correlation. Thanks to the excellent potential of integration, miniaturization and the availability of direct digital signals, the film bulk acoustic resonator has promising application for both clinical and personal use coagulation testing technologies. Full article

(This article belongs to the Special Issue Acoustic Wave Resonator-Based Sensors)

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13 pages, 3685 KiB

Open AccessArticle

A New Measurement Approach for Small Deformations of Soil Specimens Using Fiber Bragg Grating Sensors

by Dong-Sheng Xu

School of Civil Engineering and Mechanics, Huazhong University of Science and Technology, 1037 Luoyu Rd., Wuhan 430074, China

Sensors 2017, 17(5), 1016; https://doi.org/10.3390/s17051016 - 4 May 2017

Cited by 30 | Viewed by 5378

Abstract

A measurement approach for small deformations of soil specimens has been proposed in this study. The proposed approach consists of a small deformation transducer (SDT) based on fiber Bragg grating sensors which could provide an alternative tool to measure local small deformations of [...] Read more.

A measurement approach for small deformations of soil specimens has been proposed in this study. The proposed approach consists of a small deformation transducer (SDT) based on fiber Bragg grating sensors which could provide an alternative tool to measure local small deformations of a soil specimen with high accuracy. The working principle, design procedures, calibrations and applications of the SDT are presented. An analytical solution is derived to obtain the relationship between the small deformation of the transducer and the wavelength shift of the FBG sensor, which was further evident in the laboratory calibration tests. The measurement range and resolution of the SDT can be adjusted by choosing different length and thickness of the material. The SDT can achieve a strain resolution of 4.45 micro-strains for a soil specimen with 80 mm in height. Measurement errors and stability were also examined and the results show that the maximum measurement error was around 0.01 mm. The designed SDT was further installed in a modified triaxial apparatus. Three shearing tests under different confining pressures were conducted. Results measured by the newly developed SDT are analyzed with comparisons to the results using external linear variable differential transformer (LVDT) transducers. The results provide evidence that this measurement approach is suitable for measuring the local deformations of soil specimens with high accuracy and stability. Full article

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

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13 pages, 8481 KiB

Open AccessArticle

Analysis of the Damping Characteristics of Cylindrical Resonators Influenced by Piezoelectric Electrodes

by Jiangkun Sun

, Yulie Wu^*, Xiang Xi, Yongmeng Zhang and Xuezhong Wu^*

College of Mechatronics Engineering and Automation, National University of Defense Technology, Changsha 410073, China

Sensors 2017, 17(5), 1017; https://doi.org/10.3390/s17051017 - 4 May 2017

Cited by 10 | Viewed by 4926

Abstract

The cylindrical resonator gyroscope (CRG) is a typical Coriolis vibratory gyroscope whose performance is mostly influenced by the damping characteristic of the cylindrical resonator. However, the tremendous damping influences caused by pasting piezoelectric electrodes on the gyroscope, which degrades the performance to a [...] Read more.

The cylindrical resonator gyroscope (CRG) is a typical Coriolis vibratory gyroscope whose performance is mostly influenced by the damping characteristic of the cylindrical resonator. However, the tremendous damping influences caused by pasting piezoelectric electrodes on the gyroscope, which degrades the performance to a large extent, have rarely been studied. In this paper, the dynamical model is established to analyze various forms of energy consumption. In addition, a FE COMSOL model is also created to discuss the damping influences of several significant parameters of the adhesive layer and piezoelectric electrodes, respectively, and then explicit influence laws are obtained. Simulation results demonstrate that the adhesive layer has some impact on the damping characteristic, but it not significant. The Q factor decreases about 30.31% in total as a result of pasting piezoelectric electrodes. What is more, it is discovered that piezoelectric electrodes with short length, locations away from the outside edges, proper width and well-chosen thickness are able to reduce the damping influences to a large extent. Afterwards, experiments of testing the Q factor are set up to validate the simulation values. Full article

(This article belongs to the Section Physical Sensors)

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12 pages, 1290 KiB

Open AccessArticle

Cooperative Spatial Retreat for Resilient Drone Networks

by Jin-Hyeok Kang

, Young-Min Kwon and Kyung-Joon Park^*

Department of Information and Communication Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea

Sensors 2017, 17(5), 1018; https://doi.org/10.3390/s17051018 - 3 May 2017

Cited by 9 | Viewed by 5528

Abstract

Drones are broadening their scope to various applications such as networking, package delivery, agriculture, rescue, and many more. For proper operation of drones, reliable communication should be guaranteed because drones are remotely controlled. When drones experience communication failure due to bad channel condition, [...] Read more.

Drones are broadening their scope to various applications such as networking, package delivery, agriculture, rescue, and many more. For proper operation of drones, reliable communication should be guaranteed because drones are remotely controlled. When drones experience communication failure due to bad channel condition, interference, or jamming in a certain area, one existing solution is to exploit mobility or so-called spatial retreat to evacuate them from the communication failure area. However, the conventional spatial retreat scheme moves drones in random directions, which results in inefficient movement with significant evacuation time and waste of battery lifetime. In this paper, we propose a novel spatial retreat technique that takes advantage of cooperation between drones for resilient networking, which is called cooperative spatial retreat (CSR). Our performance evaluation shows that the proposed CSR significantly outperforms existing schemes. Full article

(This article belongs to the Special Issue Selected Papers from International Conference on Ubiquitous and Future Networks (ICUFN 2016))

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17 pages, 16560 KiB

Open AccessArticle

Theoretical Analysis of the Dynamic Properties of a 2-2 Cement-Based Piezoelectric Dual-Layer Stacked Sensor under Impact Load

by Taotao Zhang, Yangchao Liao, Keping Zhang and Jun Chen^*

School of Transportation Science and Engineering, Beihang University, Beijing 100191, China

Sensors 2017, 17(5), 1019; https://doi.org/10.3390/s17051019 - 4 May 2017

Cited by 10 | Viewed by 4358

Abstract

Cement-based piezoelectric materials are widely used due to the fact that compared with common smart materials, they overcome the defects of structure-incompatibility and frequency inconsistency with a concrete structure. However, the present understanding of the mechanical behavior of cement-based piezoelectric smart materials under [...] Read more.

Cement-based piezoelectric materials are widely used due to the fact that compared with common smart materials, they overcome the defects of structure-incompatibility and frequency inconsistency with a concrete structure. However, the present understanding of the mechanical behavior of cement-based piezoelectric smart materials under impact load is still limited. The dynamic characteristics under impact load are of importance, for example, for studying the anti-collision properties of engineering structures and aircraft takeoff-landing safety. Therefore, in this paper, an analytical model was proposed to investigate the dynamic properties of a 2-2 cement-based piezoelectric dual-layer stacked sensor under impact load based on the piezoelectric effect. Theoretical solutions are obtained by utilizing the variable separation and Duhamel integral method. To simulate the impact load and verify the theory, three types of loads, including atransient step load, isosceles triangle load and haversine wave load, are considered and the comparisons between the theoretical results, Li’s results and numerical results are presented by using the control variate method and good agreement is found. Furthermore, the influences of several parameters were discussed and other conclusions about this sensor are also given. This should prove very helpful for the design and optimization of the 2-2 cement-based piezoelectric dual-layer stacked sensor in engineering. Full article

(This article belongs to the Section Physical Sensors)

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14 pages, 1754 KiB

Open AccessArticle

Non-Uniform Fusion Tree Generation in a Dynamic Multi-Sensor System

by Kyuoke Yeun^1,2,* and Daeyoung Kim²

¹ Agency for Defense Development, Yuseong-gu Soonam-dong, Daejeon 34186, Korea

² School of Computing, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro Yuseong-gu, Daejeon 34141, Korea

Sensors 2017, 17(5), 1020; https://doi.org/10.3390/s17051020 - 4 May 2017

Cited by 1 | Viewed by 3536

Abstract

This paper addresses the proposal that the number of processed air tracks of a two-tier fusion process can be increased by applying a balanced fusion tree which can balance tracks across local fusion nodes. Every fusion cycle, a fusion process combines duplicate tracks [...] Read more.

This paper addresses the proposal that the number of processed air tracks of a two-tier fusion process can be increased by applying a balanced fusion tree which can balance tracks across local fusion nodes. Every fusion cycle, a fusion process combines duplicate tracks from multiple radars and creates a single integrated air picture (SIAP). The two-tier fusion process divides the fusion process into local and global. The results of the local fusion process, executed at local fusion nodes, are used in the global fusion process. This hierarchical structure can be modeled as a fusion tree: each radar, local fusion node, and the central server is a leaf, internode, and the root, respectively. This paper presents a non-uniform fusion tree generation (NU-FTG) algorithm based on clustering approach. In the NU-FTG, radars with higher scores get more chances to become local fusion nodes. The score of a radar is in proportion to the number of tracks of the radar and its neighbors. All radars execute the NU-FTG independently with the information of their neighbors. Any prior information, such as the appropriate number of local fusion nodes, predefined tree structure, or position of radars, is not required. The NU-FTG is evaluated in the OPNET (Optimized Network Engineering Tool), network simulator. Simulation results show that the NU-FTG performs better than existing clustering methods. Full article

(This article belongs to the Section Sensor Networks)

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17 pages, 14393 KiB

Open AccessArticle

Design and Development of a Nearable Wireless System to Control Indoor Air Quality and Indoor Lighting Quality

by Francesco Salamone^1,*

, Lorenzo Belussi¹

, Ludovico Danza¹, Theodore Galanos², Matteo Ghellere¹ and Italo Meroni¹

¹ ITC-CNR, Construction Technologies Institute—National Research Council of Italy, Via Lombardia 49-20098 San Giuliano M.se, Italy

² NEAPOLI SDN BHD 894646-M Environmental Design and Engineering, D-8-5, Megan Avenue 1, 189 Jalan Tun Razak, 50400 Kuala Lumpur, Malaysia

Sensors 2017, 17(5), 1021; https://doi.org/10.3390/s17051021 - 4 May 2017

Cited by 82 | Viewed by 12774

Abstract

The article describes the results of the project “open source smart lamp” aimed at designing and developing a smart object able to manage and control the indoor environmental quality (IEQ) of the built environment. A first version of this smart object, built following [...] Read more.

The article describes the results of the project “open source smart lamp” aimed at designing and developing a smart object able to manage and control the indoor environmental quality (IEQ) of the built environment. A first version of this smart object, built following a do-it-yourself (DIY) approach using a microcontroller, an integrated temperature and relative humidity sensor, and techniques of additive manufacturing, allows the adjustment of the indoor thermal comfort quality (ICQ), by interacting directly with the air conditioner. As is well known, the IEQ is a holistic concept including indoor air quality (IAQ), indoor lighting quality (ILQ) and acoustic comfort, besides thermal comfort. The upgrade of the smart lamp bridges the gap of the first version of the device providing the possibility of interaction with the air exchange unit and lighting system in order to get an overview of the potential of a nearable device in the management of the IEQ. The upgraded version was tested in a real office equipped with mechanical ventilation and an air conditioning system. This office was occupied by four workers. The experiment is compared with a baseline scenario and the results show how the application of the nearable device effectively optimizes both IAQ and ILQ. Full article

(This article belongs to the Special Issue Selected Papers from the 3rd International Electronic Conference on Sensors and Applications)

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23 pages, 5012 KiB

Open AccessArticle

A Probabilistic and Highly Efficient Topology Control Algorithm for Underwater Cooperating AUV Networks

by Ning Li^1,*

, Baran Cürüklü², Joaquim Bastos³, Victor Sucasas⁴, Jose Antonio Sanchez Fernandez¹ and Jonathan Rodriguez⁴

¹ Escuela Técnica Superior de Ingeniería y Sistemas de Telecomunicación, Campus Sur Universidad Politécnica de Madrid (UPM), 28031 Madrid, Spain

² Division of Intelligent Future Technologies, School of Innovation, Design and Engineering, Malardalen University, 721 23 Västerås, Sweden

³ Instituto de Telecomunicações, Campus de Santiago, 3810-193 Aveiro, Portugal

⁴ Universidade de Aveiro, Campus Universitario de Santiago, 3810-193 Aveiro, Portugal

Sensors 2017, 17(5), 1022; https://doi.org/10.3390/s17051022 - 4 May 2017

Cited by 25 | Viewed by 6478

Abstract

The aim of the Smart and Networking Underwater Robots in Cooperation Meshes (SWARMs) project is to make autonomous underwater vehicles (AUVs), remote operated vehicles (ROVs) and unmanned surface vehicles (USVs) more accessible and useful. To achieve cooperation and communication between different AUVs, these [...] Read more.

The aim of the Smart and Networking Underwater Robots in Cooperation Meshes (SWARMs) project is to make autonomous underwater vehicles (AUVs), remote operated vehicles (ROVs) and unmanned surface vehicles (USVs) more accessible and useful. To achieve cooperation and communication between different AUVs, these must be able to exchange messages, so an efficient and reliable communication network is necessary for SWARMs. In order to provide an efficient and reliable communication network for mission execution, one of the important and necessary issues is the topology control of the network of AUVs that are cooperating underwater. However, due to the specific properties of an underwater AUV cooperation network, such as the high mobility of AUVs, large transmission delays, low bandwidth, etc., the traditional topology control algorithms primarily designed for terrestrial wireless sensor networks cannot be used directly in the underwater environment. Moreover, these algorithms, in which the nodes adjust their transmission power once the current transmission power does not equal an optimal one, are costly in an underwater cooperating AUV network. Considering these facts, in this paper, we propose a Probabilistic Topology Control (PTC) algorithm for an underwater cooperating AUV network. In PTC, when the transmission power of an AUV is not equal to the optimal transmission power, then whether the transmission power needs to be adjusted or not will be determined based on the AUV’s parameters. Each AUV determines their own transmission power adjustment probability based on the parameter deviations. The larger the deviation, the higher the transmission power adjustment probability is, and vice versa. For evaluating the performance of PTC, we combine the PTC algorithm with the Fuzzy logic Topology Control (FTC) algorithm and compare the performance of these two algorithms. The simulation results have demonstrated that the PTC is efficient at reducing the transmission power adjustment ratio while improving the network performance. Full article

(This article belongs to the Special Issue Sensing Technologies for Autonomy and Cooperation in Underwater Networked Robot Systems)

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13 pages, 4928 KiB

Open AccessArticle

A New Electromagnetic Acoustic Transducer Design for Generating and Receiving S0 Lamb Waves in Ferromagnetic Steel Plate

by Jianpeng He¹, Steve Dixon², Samuel Hill² and Ke Xu^3,*

¹ National Engineering Research Center of Advanced Rolling Technology, University of Science and Technology Beijing, Beijing 100083, China

² Department of Physics, University of Warwick, Coventry CV4 7AL, UK

³ Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing 100083, China

Sensors 2017, 17(5), 1023; https://doi.org/10.3390/s17051023 - 4 May 2017

Cited by 25 | Viewed by 6195

Abstract

Electromagnetic acoustic transducers (EMATs) are non-contact, ultrasonic transducers that are usually kept within 5 mm from the sample surface to obtain a sufficient signal-to-noise ratio (SNR). One important issue associated with operation on a ferromagnetic plate is that the strong attraction force from [...] Read more.

Electromagnetic acoustic transducers (EMATs) are non-contact, ultrasonic transducers that are usually kept within 5 mm from the sample surface to obtain a sufficient signal-to-noise ratio (SNR). One important issue associated with operation on a ferromagnetic plate is that the strong attraction force from the magnet can affect measurements and make scanning difficult. This paper investigates a method to generate fundamental, symmetric Lamb waves on a ferromagnetic plate. A coil-only, low-weight, generation EMAT is designed and investigated, operating at lift-offs of over 5 mm. Another design of an EMAT is investigated using a rectangular magnet with a much higher lift-off than the coil, of up to 19 mm. This results in a much lower force between the EMAT and sample, making scanning the EMAT much easier. Full article

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

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14 pages, 5798 KiB

Open AccessArticle

Development of a Spectrophotometric System to Detect White Striping Physiopathy in Whole Chicken Carcasses

by Maria Victoria Traffano-Schiffo¹

, Marta Castro-Giraldez¹, Ricardo J. Colom² and Pedro J. Fito^1,*

¹ Instituto Universitario de Ingeniería de Alimentos para el Desarrollo, Universitat Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia, Spain

² Instituto de Instrumentación para Imagen Molecular, Universitat Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia, Spain

Sensors 2017, 17(5), 1024; https://doi.org/10.3390/s17051024 - 4 May 2017

Cited by 30 | Viewed by 5684

Abstract

Due to the high intensification of poultry production in recent years, white chicken breast striping is one of the most frequently seen myopathies. The aim of this research was to develop a spectrophotometry-based sensor to detect white striping physiopathy in chicken breast meat [...] Read more.

Due to the high intensification of poultry production in recent years, white chicken breast striping is one of the most frequently seen myopathies. The aim of this research was to develop a spectrophotometry-based sensor to detect white striping physiopathy in chicken breast meat in whole chicken carcasses with skin. Experiments were carried out using normal and white striping breasts. In order to understand the mechanism involved in this physiopathy, the different tissues that conform each breast were analyzed. Permittivity in radiofrequency (40 Hz to 1 MHz) was measured using two different sensors; a sensor with two flat plates to analyze the whole breast with skin (NB or WSB), and a two needles with blunt-ended sensor to analyze the different surface tissues of the skinless breast. In the microwave range (500 MHz to 20 GHz), permittivity was measured as just was described for the two needles with blunt-ended sensor. Moreover, fatty acids composition was determined by calorimetry techniques from −40 °C to 50 °C at 5 °C/min after previously freeze-drying the samples, and pH, microstructure by Cryo-SEM and binocular loupe structure were also analyzed. The results showed that the white striping physiopathy consists of the partial breakdown of the pectoral muscle causing an increase in fatty acids, reducing the quality of the meat. It was possible to detect white striping physiopathy in chicken carcasses with skin using spectrophotometry of radiofrequency spectra. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Spain 2017)

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13 pages, 4231 KiB

Open AccessArticle

Supramolecular Recognition of Escherichia coli Bacteria by Fluorescent Oligo(Phenyleneethynylene)s with Mannopyranoside Termini Groups

by Enrique Arias¹

, Maria Teresa Méndez¹, Eduardo Arias^1,*, Ivana Moggio^1,*, Antonio Ledezma¹, Jorge Romero¹, Giancarlo Margheri² and Emilia Giorgetti²

¹ Centro de Investigación en Química Aplicada (CIQA), Blvd. Enrique Reyna 140, Saltillo 25294, Mexico

² Istituto dei Sistemi Complessi Via Madonna del Piano 10, Sesto Fiorentino 50019, Italy

Sensors 2017, 17(5), 1025; https://doi.org/10.3390/s17051025 - 4 May 2017

Cited by 11 | Viewed by 5606

Abstract

Escherichia coli is one the most common bacteria responsible of uropathogenic diseases, which motives the search for rapid and easy methods of detection. By taking advantage of the specific interactions between mannose and type 1 fimbriae, in this work two fluorescent phenyleneethynylene (PE) [...] Read more.

Escherichia coli is one the most common bacteria responsible of uropathogenic diseases, which motives the search for rapid and easy methods of detection. By taking advantage of the specific interactions between mannose and type 1 fimbriae, in this work two fluorescent phenyleneethynylene (PE) trimers bearing one or two 4-aminophenyl-α-D-mannopyranoside termini groups were synthesized for the detection of E. coli. Three bacterial strains: ORN 178 (fimbriae I expression), ORN 208 (mutant serotype with no fimbriae expression) and one obtained from a local hospital (SS3) were used. Laser Scanning Confocal Microscopy (LSCM) and Surface Plasmon Resonance (SPR) were applied for the interaction studies following two different approaches: (1) mixing the oligomer solutions with the bacterial suspension, which permitted the observation of stained bacteria and by (2) biosensing as thin films, where bacteria adhered on the surface-functionalized substrate. LSCM allows one to easily visualize that two mannose groups are necessary to have a specific interaction with the fimbriae 1. The sensitivity of SPR assays to E. coli was 10⁴ colony forming unit (CFU)/mL at 50 µL/min flow rate. The combination of PE units with two mannose groups results in a novel molecule that can be used as a specific fluorescent marker as well as a transducer for the detection of E. coli. Full article

(This article belongs to the Special Issue Sensors for Toxic and Pathogen Detection)

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15 pages, 999 KiB

Open AccessArticle

Secrecy Performance Analysis of Cognitive Sensor Radio Networks with an EH-Based Eavesdropper

by Aiwei Sun^1,*,†, Tao Liang^2,† and Bolun Li^1,†

¹ Institute of Communications Engineering, PLA University of Science and Technology, No. 2 Biaoying, Qinhuai District, Nanjing 210007, China

² Nanjing Telecommunication Technology Institute, No. 18 Houbiaoying, Qinhuai District, Nanjing 210007, China

^† These authors contributed equally to this work.

Sensors 2017, 17(5), 1026; https://doi.org/10.3390/s17051026 - 4 May 2017

Cited by 8 | Viewed by 4521

Abstract

Security and privacy are crucial for cognitive sensor radio networks (CSRNs) due to the possible eavesdropping between secondary sensors and the secondary fusion center. Motivated by this observation, we investigate the physical layer security performance of CSRNs with an external energy harvesting (EH)-based [...] Read more.

Security and privacy are crucial for cognitive sensor radio networks (CSRNs) due to the possible eavesdropping between secondary sensors and the secondary fusion center. Motivated by this observation, we investigate the physical layer security performance of CSRNs with an external energy harvesting (EH)-based eavesdropper. Considering the underlay working paradigm of CSRNs, the transmit power of the secondary sensor node must be adjusted to guarantee the quality-of-service (

Q o S

) of the primary user. Hence, two different interference power constraint scenarios are studied in this paper. To give an intuitive insight into the secrecy performance of the considered wiretap scenarios, we have derived the closed-form analytical expressions of secrecy outage probability for both of the considered cases. Monte Carlo simulation results are also performed to verify the theoretical analysis derived, and show the effect of various parameters on the system performance. Full article

(This article belongs to the Special Issue Wireless Rechargeable Sensor Networks)

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18 pages, 3079 KiB

Open AccessArticle

Multiple Two-Way Time Message Exchange (TTME) Time Synchronization for Bridge Monitoring Wireless Sensor Networks

by Fanrong Shi^1,*

, Xianguo Tuo^1,2,3,*, Simon X. Yang³

, Huailiang Li¹ and Rui Shi⁴

¹ Robot Technology Used for Special Environment Key Laboratory of Sichuan Province, Southwest University of Science and Technology, Mianyang 621010, China

² College of Chemistry and Environment, Sichuan University of Science and Engineering, Zigong 643000, China

³ Advanced Robotics and Intelligent Systems (ARIS) Laboratory, School of Engineering, University of Guelph, Guelph, ON N1G 2W1, Canada

⁴ State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China

Sensors 2017, 17(5), 1027; https://doi.org/10.3390/s17051027 - 4 May 2017

Cited by 19 | Viewed by 5430

Abstract

Wireless sensor networks (WSNs) have been widely used to collect valuable information in Structural Health Monitoring (SHM) of bridges, using various sensors, such as temperature, vibration and strain sensors. Since multiple sensors are distributed on the bridge, accurate time synchronization is very important [...] Read more.

Wireless sensor networks (WSNs) have been widely used to collect valuable information in Structural Health Monitoring (SHM) of bridges, using various sensors, such as temperature, vibration and strain sensors. Since multiple sensors are distributed on the bridge, accurate time synchronization is very important for multi-sensor data fusion and information processing. Based on shape of the bridge, a spanning tree is employed to build linear topology WSNs and achieve time synchronization in this paper. Two-way time message exchange (TTME) and maximum likelihood estimation (MLE) are employed for clock offset estimation. Multiple TTMEs are proposed to obtain a subset of TTME observations. The time out restriction and retry mechanism are employed to avoid the estimation errors that are caused by continuous clock offset and software latencies. The simulation results show that the proposed algorithm could avoid the estimation errors caused by clock drift and minimize the estimation error due to the large random variable delay jitter. The proposed algorithm is an accurate and low complexity time synchronization algorithm for bridge health monitoring. Full article

(This article belongs to the Special Issue Sensors for Transportation)

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18 pages, 6325 KiB

Open AccessArticle

Adaptive Energy-Efficient Target Detection Based on Mobile Wireless Sensor Networks

by Tengyue Zou^*, Zhenjia Li, Shuyuan Li and Shouying Lin

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

Sensors 2017, 17(5), 1028; https://doi.org/10.3390/s17051028 - 4 May 2017

Cited by 10 | Viewed by 4758

Abstract

Target detection is a widely used application for area surveillance, elder care, and fire alarms; its purpose is to find a particular object or event in a region of interest. Usually, fixed observing stations or static sensor nodes are arranged uniformly in the [...] Read more.

Target detection is a widely used application for area surveillance, elder care, and fire alarms; its purpose is to find a particular object or event in a region of interest. Usually, fixed observing stations or static sensor nodes are arranged uniformly in the field. However, each part of the field has a different probability of being intruded upon; if an object suddenly enters an area with few guardian devices, a loss of detection will occur, and the stations in the safe areas will waste their energy for a long time without any discovery. Thus, mobile wireless sensor networks may benefit from adaptation and pertinence in detection. Sensor nodes equipped with wheels are able to move towards the risk area via an adaptive learning procedure based on Bayesian networks. Furthermore, a clustering algorithm based on k-means++ and an energy control mechanism is used to reduce the energy consumption of nodes. The extended Kalman filter and a voting data fusion method are employed to raise the localization accuracy of the target. The simulation and experimental results indicate that this new system with adaptive energy-efficient methods is able to achieve better performance than the traditional ones. Full article

(This article belongs to the Special Issue Mobile Sensing Applications)

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12 pages, 2199 KiB

Open AccessArticle

Noise Attenuation Performance of a Helmholtz Resonator Array Consist of Several Periodic Parts

by Dizi Wu¹, Nan Zhang², Cheuk Ming Mak³

and Chenzhi Cai^3,*

¹ School of Civil Engineering, Central South University, Changsha 410083, China

² School of Architecture and Art, Central South University, Changsha 410083, China

³ Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong, China

Sensors 2017, 17(5), 1029; https://doi.org/10.3390/s17051029 - 4 May 2017

Cited by 20 | Viewed by 6933

Abstract

The acoustic performance of the ducted Helmholtz resonator (HR) system is analyzed theoretically and numerically. The periodic HR array could provide a wider noise attenuation band due to the coupling of the Bragg reflection and the HR’s resonance. However, the transmission loss achieved [...] Read more.

The acoustic performance of the ducted Helmholtz resonator (HR) system is analyzed theoretically and numerically. The periodic HR array could provide a wider noise attenuation band due to the coupling of the Bragg reflection and the HR’s resonance. However, the transmission loss achieved by a periodic HR array is mainly dependent on the number of HRs, which restricted by the available space in the longitudinal direction of the duct. The full distance along the longitudinal direction of the duct for HR’s installation is sometimes unavailable in practical applications. Only several pieces of the duct may be available for the installation. It is therefore that this paper concentrates on the acoustic performance of a HR array consisting of several periodic parts. The transfer matrix method and the Bragg theory are used to investigate wave propagation in the duct. The theoretical prediction results show good agreement with the Finite Element Method (FEM) simulation results. The present study provides a practical way in noise control application of ventilation ductwork system by utilizing the advantage of periodicity with the limitation of available completed installation length for HRs. Full article

(This article belongs to the Special Issue Acoustic Wave Resonator-Based Sensors)

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16 pages, 4985 KiB

Open AccessArticle

Channel and Timeslot Co-Scheduling with Minimal Channel Switching for Data Aggregation in MWSNs

by Sanggil Yeoum, Byungseok Kang

, Jinkyu Lee and Hyunseung Choo^*

College of Software, Sungkyunkwan University, Suwon 16419, Korea

Sensors 2017, 17(5), 1030; https://doi.org/10.3390/s17051030 - 4 May 2017

Cited by 15 | Viewed by 4177

Abstract

Collision-free transmission and efficient data transfer between nodes can be achieved through a set of channels in multichannel wireless sensor networks (MWSNs). While using multiple channels, we have to carefully consider channel interference, channel and time slot (resources) optimization, channel switching delay, and [...] Read more.

Collision-free transmission and efficient data transfer between nodes can be achieved through a set of channels in multichannel wireless sensor networks (MWSNs). While using multiple channels, we have to carefully consider channel interference, channel and time slot (resources) optimization, channel switching delay, and energy consumption. Since sensor nodes operate on low battery power, the energy consumed in channel switching becomes an important challenge. In this paper, we propose channel and time slot scheduling for minimal channel switching in MWSNs, while achieving efficient and collision-free transmission between nodes. The proposed scheme constructs a duty-cycled tree while reducing the amount of channel switching. As a next step, collision-free time slots are assigned to every node based on the minimal data collection delay. The experimental results demonstrate that the validity of our scheme reduces the amount of channel switching by 17.5%, reduces energy consumption for channel switching by 28%, and reduces the schedule length by 46%, as compared to the existing schemes. Full article

(This article belongs to the Section Sensor Networks)

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19 pages, 1987 KiB

Open AccessArticle

Public Auditing with Privacy Protection in a Multi-User Model of Cloud-Assisted Body Sensor Networks

by Song Li¹, Jie Cui^1,*

, Hong Zhong¹ and Lu Liu²

¹ School of Computer Science and Technology, Anhui University, Hefei 230601, China

² Department of Computing and Mathematics, University of Derby, Derby DE22 1GB, UK

Sensors 2017, 17(5), 1032; https://doi.org/10.3390/s17051032 - 5 May 2017

Cited by 7 | Viewed by 6080

Abstract

Wireless Body Sensor Networks (WBSNs) are gaining importance in the era of the Internet of Things (IoT). The modern medical system is a particular area where the WBSN techniques are being increasingly adopted for various fundamental operations. Despite such increasing deployments of WBSNs, [...] Read more.

Wireless Body Sensor Networks (WBSNs) are gaining importance in the era of the Internet of Things (IoT). The modern medical system is a particular area where the WBSN techniques are being increasingly adopted for various fundamental operations. Despite such increasing deployments of WBSNs, issues such as the infancy in the size, capabilities and limited data processing capacities of the sensor devices restrain their adoption in resource-demanding applications. Though providing computing and storage supplements from cloud servers can potentially enrich the capabilities of the WBSNs devices, data security is one of the prevailing issues that affects the reliability of cloud-assisted services. Sensitive applications such as modern medical systems demand assurance of the privacy of the users’ medical records stored in distant cloud servers. Since it is economically impossible to set up private cloud servers for every client, auditing data security managed in the remote servers has necessarily become an integral requirement of WBSNs’ applications relying on public cloud servers. To this end, this paper proposes a novel certificateless public auditing scheme with integrated privacy protection. The multi-user model in our scheme supports groups of users to store and share data, thus exhibiting the potential for WBSNs’ deployments within community environments. Furthermore, our scheme enriches user experiences by offering public verifiability, forward security mechanisms and revocation of illegal group members. Experimental evaluations demonstrate the security effectiveness of our proposed scheme under the Random Oracle Model (ROM) by outperforming existing cloud-assisted WBSN models. Full article

(This article belongs to the Collection Smart Industrial Wireless Sensor Networks)

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15 pages, 5443 KiB

Open AccessArticle

Fine Particle Sensor Based on Multi-Angle Light Scattering and Data Fusion

by Wenjia Shao

, Hongjian Zhang and Hongliang Zhou^*

State Key Laboratory of Industrial Control Technology, College of Control Science and Engineering, Zhejiang University, Hangzhou 310027, China

Sensors 2017, 17(5), 1033; https://doi.org/10.3390/s17051033 - 4 May 2017

Cited by 34 | Viewed by 9157

Abstract

Meteorological parameters such as relative humidity have a significant impact on the precision of PM2.5 measurement instruments based on light scattering. Instead of adding meteorological sensors or dehumidification devices used widely in commercial PM2.5 measurement instruments, a novel particle sensor based on multi-angle [...] Read more.

Meteorological parameters such as relative humidity have a significant impact on the precision of PM2.5 measurement instruments based on light scattering. Instead of adding meteorological sensors or dehumidification devices used widely in commercial PM2.5 measurement instruments, a novel particle sensor based on multi-angle light scattering and data fusion is proposed to eliminate the effect of meteorological factors. Three photodiodes are employed to collect the scattered light flux at three distinct angles. Weather index is defined as the ratio of scattered light fluxes collected at the 40° and 55° angles, which can be used to distinguish the mass median diameter variation caused by different meteorological parameters. Simulations based on Lorenz-Mie theory and field experiments establish the feasibility of this scheme. Experimental results indicate that mass median diameter has less effect on the photodiode at the 55° angle in comparison with photodiodes at the 40° angle and 140° angle. After correction using the weather index, the photodiode at the 40° angle yielded the best results followed by photodiodes at the 55° angle and the 140° angle. 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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17 pages, 1812 KiB

Open AccessArticle

Unsupervised Machine Learning for Developing Personalised Behaviour Models Using Activity Data

by Laura Fiorini^1,*, Filippo Cavallo¹

, Paolo Dario¹, Alexandra Eavis² and Praminda Caleb-Solly³

¹ The BioRobotics Institute, Scuola Superiore Sant’Anna, Pontedera, Pisa 56025, Italy

² Alcove Limited, 44 Westbridge Road, London SW11 3PW, UK

³ Bristol Robotics Laboratory, University of West England, Bristol BS16 1QY, UK

Sensors 2017, 17(5), 1034; https://doi.org/10.3390/s17051034 - 4 May 2017

Cited by 29 | Viewed by 7854 | Correction

Abstract

The goal of this study is to address two major issues that undermine the large scale deployment of smart home sensing solutions in people’s homes. These include the costs associated with having to install and maintain a large number of sensors, and the [...] Read more.

The goal of this study is to address two major issues that undermine the large scale deployment of smart home sensing solutions in people’s homes. These include the costs associated with having to install and maintain a large number of sensors, and the pragmatics of annotating numerous sensor data streams for activity classification. Our aim was therefore to propose a method to describe individual users’ behavioural patterns starting from unannotated data analysis of a minimal number of sensors and a ”blind” approach for activity recognition. The methodology included processing and analysing sensor data from 17 older adults living in community-based housing to extract activity information at different times of the day. The findings illustrate that 55 days of sensor data from a sensor configuration comprising three sensors, and extracting appropriate features including a “busyness” measure, are adequate to build robust models which can be used for clustering individuals based on their behaviour patterns with a high degree of accuracy (>85%). The obtained clusters can be used to describe individual behaviour over different times of the day. This approach suggests a scalable solution to support optimising the personalisation of care by utilising low-cost sensing and analysis. This approach could be used to track a person’s needs over time and fine-tune their care plan on an ongoing basis in a cost-effective manner. Full article

(This article belongs to the Special Issue Sensors for Ambient Assisted Living, Ubiquitous and Mobile Health)

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18 pages, 12264 KiB

Open AccessArticle

Design of a Single Channel Modulated Wideband Converter for Wideband Spectrum Sensing: Theory, Architecture and Hardware Implementation

by Weisong Liu^1,*

, Zhitao Huang¹, Xiang Wang¹ and Weichao Sun²

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

² Southwest Electronics and Telecommunication Technology Research Institute, Chengdu 610041, China

Sensors 2017, 17(5), 1035; https://doi.org/10.3390/s17051035 - 4 May 2017

Cited by 21 | Viewed by 5268

Abstract

In a cognitive radio sensor network (CRSN), wideband spectrum sensing devices which aims to effectively exploit temporarily vacant spectrum intervals as soon as possible are of great importance. However, the challenge of increasingly high signal frequency and wide bandwidth requires an extremely high [...] Read more.

In a cognitive radio sensor network (CRSN), wideband spectrum sensing devices which aims to effectively exploit temporarily vacant spectrum intervals as soon as possible are of great importance. However, the challenge of increasingly high signal frequency and wide bandwidth requires an extremely high sampling rate which may exceed today’s best analog-to-digital converters (ADCs) front-end bandwidth. Recently, the newly proposed architecture called modulated wideband converter (MWC), is an attractive analog compressed sensing technique that can highly reduce the sampling rate. However, the MWC has high hardware complexity owing to its parallel channel structure especially when the number of signals increases. In this paper, we propose a single channel modulated wideband converter (SCMWC) scheme for spectrum sensing of band-limited wide-sense stationary (WSS) signals. With one antenna or sensor, this scheme can save not only sampling rate but also hardware complexity. We then present a new, SCMWC based, single node CR prototype System, on which the spectrum sensing algorithm was tested. Experiments on our hardware prototype show that the proposed architecture leads to successful spectrum sensing. And the total sampling rate as well as hardware size is only one channel’s consumption of MWC. Full article

(This article belongs to the Special Issue Cognitive Radio Sensing and Sensor Networks)

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15 pages, 3648 KiB

Open AccessArticle

Spectroscopic Diagnosis of Arsenic Contamination in Agricultural Soils

by Tiezhu Shi¹, Huizeng Liu^1,2, Yiyun Chen³

, Teng Fei^3,4

, Junjie Wang¹ and Guofeng Wu^1,*

¹ Key Laboratory for Geo-Environmental Monitoring of Coastal Zone of National Administration of Surveying, Mapping and GeoInformation & Shenzhen Key Laboratory of Spatial Smart Sensing and Services & College of Life Sciences and Oceanography, Shenzhen University, 518060 Shenzhen, China

² Department of Geography, Hong Kong Baptist University, Kowloon Tong, Kowloon, Hong Kong, China

³ School of Resource and Environmental Sciences, Wuhan University, 430079 Wuhan, China

⁴ Suzhou Institute of Wuhan University, 215000 Suzhou, China

Sensors 2017, 17(5), 1036; https://doi.org/10.3390/s17051036 - 4 May 2017

Cited by 26 | Viewed by 5115

Abstract

This study investigated the abilities of pre-processing, feature selection and machine-learning methods for the spectroscopic diagnosis of soil arsenic contamination. The spectral data were pre-processed by using Savitzky-Golay smoothing, first and second derivatives, multiplicative scatter correction, standard normal variate, and mean centering. Principle [...] Read more.

This study investigated the abilities of pre-processing, feature selection and machine-learning methods for the spectroscopic diagnosis of soil arsenic contamination. The spectral data were pre-processed by using Savitzky-Golay smoothing, first and second derivatives, multiplicative scatter correction, standard normal variate, and mean centering. Principle component analysis (PCA) and the RELIEF algorithm were used to extract spectral features. Machine-learning methods, including random forests (RF), artificial neural network (ANN), radial basis function- and linear function- based support vector machine (RBF- and LF-SVM) were employed for establishing diagnosis models. The model accuracies were evaluated and compared by using overall accuracies (OAs). The statistical significance of the difference between models was evaluated by using McNemar’s test (Z value). The results showed that the OAs varied with the different combinations of pre-processing, feature selection, and classification methods. Feature selection methods could improve the modeling efficiencies and diagnosis accuracies, and RELIEF often outperformed PCA. The optimal models established by RF (OA = 86%), ANN (OA = 89%), RBF- (OA = 89%) and LF-SVM (OA = 87%) had no statistical difference in diagnosis accuracies (Z < 1.96, p < 0.05). These results indicated that it was feasible to diagnose soil arsenic contamination using reflectance spectroscopy. The appropriate combination of multivariate methods was important to improve diagnosis accuracies. Full article

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

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22 pages, 5660 KiB

Open AccessArticle

Real-Time Motion Tracking for Mobile Augmented/Virtual Reality Using Adaptive Visual-Inertial Fusion

by Wei Fang¹, Lianyu Zheng^1,*, Huanjun Deng² and Hongbo Zhang¹

¹ School of Mechanical Engineering and Automation, Beihang University, Xueyuan Road, Haidian District, Beijing 100191, China

² Beijing Baofengmojing Technologies Co., Ltd., Zhichun Road, Haidian District, Beijing 100191, China

Sensors 2017, 17(5), 1037; https://doi.org/10.3390/s17051037 - 5 May 2017

Cited by 65 | Viewed by 11473

Abstract

In mobile augmented/virtual reality (AR/VR), real-time 6-Degree of Freedom (DoF) motion tracking is essential for the registration between virtual scenes and the real world. However, due to the limited computational capacity of mobile terminals today, the latency between consecutive arriving poses would damage [...] Read more.

In mobile augmented/virtual reality (AR/VR), real-time 6-Degree of Freedom (DoF) motion tracking is essential for the registration between virtual scenes and the real world. However, due to the limited computational capacity of mobile terminals today, the latency between consecutive arriving poses would damage the user experience in mobile AR/VR. Thus, a visual-inertial based real-time motion tracking for mobile AR/VR is proposed in this paper. By means of high frequency and passive outputs from the inertial sensor, the real-time performance of arriving poses for mobile AR/VR is achieved. In addition, to alleviate the jitter phenomenon during the visual-inertial fusion, an adaptive filter framework is established to cope with different motion situations automatically, enabling the real-time 6-DoF motion tracking by balancing the jitter and latency. Besides, the robustness of the traditional visual-only based motion tracking is enhanced, giving rise to a better mobile AR/VR performance when motion blur is encountered. Finally, experiments are carried out to demonstrate the proposed method, and the results show that this work is capable of providing a smooth and robust 6-DoF motion tracking for mobile AR/VR in real-time. Full article

(This article belongs to the Special Issue Intelligent Sensing and Information Mining—Selected Papers from the 10th International Conference on Sensing Technology)

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20 pages, 9525 KiB

Open AccessArticle

Radio Frequency Compatibility Evaluation of S Band Navigation Signals for Future BeiDou

by Yanbo Sun¹, Rui Xue^1,*, Danfeng Zhao¹ and Dun Wang^2,*

¹ College of Information & Communication Engineering, Harbin Engineering University, Harbin 150001, China

² State Key Laboratory of Space-Ground Integrated Information Technology, Beijing 100086, China

Sensors 2017, 17(5), 1039; https://doi.org/10.3390/s17051039 - 5 May 2017

Cited by 21 | Viewed by 4974

Abstract

With L band frequency allocations for satellite navigation getting more crowded, S band (2483.5–2500 MHz) is already allocated for navigation services, where Globalstar broadcasts downlink communications to user terminals. The Indian Regional Navigation Satellite System (IRNSS) is transmitting navigation signals and Galileo exploits [...] Read more.

With L band frequency allocations for satellite navigation getting more crowded, S band (2483.5–2500 MHz) is already allocated for navigation services, where Globalstar broadcasts downlink communications to user terminals. The Indian Regional Navigation Satellite System (IRNSS) is transmitting navigation signals and Galileo exploits some potential signals in S band. Also, several candidate S band signals based on binary offset carrier (BOC), binary phase shift keying (BPSK), continuous phase modulation (CPM) and minimum shift keying-BOC (MSK-BOC) are suggested for BeiDou system (BDS). In quite narrow S band, mutual interference among these systems is inevitable, thus the compatibility issue is particularly significant for S band signal design. To explore desired S band signals for BDS, the paper firstly describes a comprehensive compatibility evaluation methods based on effective carrier-to-noise ratio degradation for acquisition and code tracking. Then a real simulation is established using space constellations, modulation schemes and received power. Finally, the worst mutual interference of BDS candidate signals with Galileo, IRNSS and Globalstar is calculated and compared. The results indicate that CPM signal is easier to allow peaceful coexistence of other systems with minimal mutual interference in S band compared to other BDS candidates. Full article

(This article belongs to the Section Remote Sensors)

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7 pages, 2495 KiB

Open AccessArticle

An All-Solid-State pH Sensor Employing Fluorine-Terminated Polycrystalline Boron-Doped Diamond as a pH-Insensitive Solution-Gate Field-Effect Transistor

by Yukihiro Shintani^1,2,*, Mikinori Kobayashi¹ and Hiroshi Kawarada^1,3

¹ Graduate School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan

² R&D Departent, Innovation Center, MK-Hdqrs, Yokogawa Electric Corporation, Japan, 2-9-32 Nakacho, Musashino, Tokyo 180-8750, Japan

³ The Kagami Memorial Laboratory for Materials Science and Technology, Waseda University, 2-8-26 Nishiwaseda, Shinjuku, Tokyo 169-0051, Japan

Sensors 2017, 17(5), 1040; https://doi.org/10.3390/s17051040 - 5 May 2017

Cited by 8 | Viewed by 5995

Abstract

A fluorine-terminated polycrystalline boron-doped diamond surface is successfully employed as a pH-insensitive SGFET (solution-gate field-effect transistor) for an all-solid-state pH sensor. The fluorinated polycrystalline boron-doped diamond (BDD) channel possesses a pH-insensitivity of less than 3mV/pH compared with a pH-sensitive oxygenated channel. With differential [...] Read more.

A fluorine-terminated polycrystalline boron-doped diamond surface is successfully employed as a pH-insensitive SGFET (solution-gate field-effect transistor) for an all-solid-state pH sensor. The fluorinated polycrystalline boron-doped diamond (BDD) channel possesses a pH-insensitivity of less than 3mV/pH compared with a pH-sensitive oxygenated channel. With differential FET (field-effect transistor) sensing, a sensitivity of 27 mv/pH was obtained in the pH range of 2–10; therefore, it demonstrated excellent performance for an all-solid-state pH sensor with a pH-sensitive oxygen-terminated polycrystalline BDD SGFET and a platinum quasi-reference electrode, respectively. Full article

(This article belongs to the Section Chemical Sensors)

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21 pages, 7909 KiB

Open AccessArticle

FM-UWB: Towards a Robust, Low-Power Radio for Body Area Networks

by Vladimir Kopta^1,2,*, John Farserotu² and Christian Enz¹

¹ Integrated Circuits Lab (ICLAB), Swiss Federal Institute of Technology (EPFL), Microcity, Rue de la Maladiére 71,2000 Neuchâtel, Switzerland

² Swiss Center for Electronics and Microtechnology (CSEM), Rue Jaquet-Droz 1, 2000 Neuchâtel, Switzerland

Sensors 2017, 17(5), 1043; https://doi.org/10.3390/s17051043 - 6 May 2017

Cited by 8 | Viewed by 7488

Abstract

The Frequency Modulated Ultra-Wideband (FM-UWB) is known as a low-power, low-complexity modulation scheme targeting low to moderate data rates in applications such as wireless body area networks. In this paper, a thorough review of all FM-UWB receivers and transmitters reported in literature is [...] Read more.

The Frequency Modulated Ultra-Wideband (FM-UWB) is known as a low-power, low-complexity modulation scheme targeting low to moderate data rates in applications such as wireless body area networks. In this paper, a thorough review of all FM-UWB receivers and transmitters reported in literature is presented. The emphasis is on trends in power reduction that exhibit an improvement by a factor 20 over the past eight years, showing the high potential of FM-UWB. The main architectural and circuit techniques that have led to this improvement are highlighted. Seldom explored potential of using higher data rates and more complex modulations is demonstrated as a way to increase energy efficiency of FM-UWB. Multi-user communication over a single Radio Frequency (RF) channel is explored in more depth and multi-channel transmission is proposed as an extension of standard FM-UWB. The two techniques provide means of decreasing network latency, improving performance, and allow the FM-UWB to accommodate the increasing number of sensor nodes in the emerging applications such as High-Density Wireless Sensor Networks. Full article

(This article belongs to the Special Issue Advances in Body Sensor Networks: Sensors, Systems, and Applications)

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13 pages, 6150 KiB

Open AccessArticle

Deformation Monitoring of Waste-Rock-Backfilled Mining Gob for Ground Control

by Tongbin Zhao¹, Yubao Zhang¹

, Zhenyu Zhang^2,*

, Zhanhai Li¹ and Shuqi Ma³

¹ State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao 266590, China

² State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China

³ School of Civil and Environmental Engineering, Nanyang Technological University, 939798 Singapore, Singapore

Sensors 2017, 17(5), 1044; https://doi.org/10.3390/s17051044 - 5 May 2017

Cited by 17 | Viewed by 5600

Abstract

Backfill mining is an effective option to mitigate ground subsidence, especially for mining under surface infrastructure, such as buildings, dams, rivers and railways. To evaluate its performance, continual long-term field monitoring of the deformation of backfilled gob is important to satisfy strict public [...] Read more.

Backfill mining is an effective option to mitigate ground subsidence, especially for mining under surface infrastructure, such as buildings, dams, rivers and railways. To evaluate its performance, continual long-term field monitoring of the deformation of backfilled gob is important to satisfy strict public scrutiny. Based on industrial Ethernet, a real-time monitoring system was established to monitor the deformation of waste-rock-backfilled gob at −700 m depth in the Tangshan coal mine, Hebei Province, China. The designed deformation sensors, based on a resistance transducer mechanism, were placed vertically between the roof and floor. Stress sensors were installed above square steel plates that were anchored to the floor strata. Meanwhile, data cables were protected by steel tubes in case of damage. The developed system continually harvested field data for three months. The results show that industrial Ethernet technology can be reliably used for long-term data transmission in complicated underground mining conditions. The monitoring reveals that the roof subsidence of the backfilled gob area can be categorized into four phases. The bearing load of the backfill developed gradually and simultaneously with the deformation of the roof strata, and started to be almost invariable when the mining face passed 97 m. Full article

(This article belongs to the Special Issue Sensors for Deformation Monitoring of Large Civil Infrastructures)

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16 pages, 366 KiB

Open AccessArticle

Flexible Fusion Structure-Based Performance Optimization Learning for Multisensor Target Tracking

by Quanbo Ge^1,2

, Zhongliang Wei^3,*, Tianfa Cheng¹, Shaodong Chen⁴ and Xiangfeng Wang⁵

¹ School of Automation, Hangzhou Dianzi University, Hangzhou 310018, China

² State Key Laboratory of Management and Control for Complex Systems, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China

³ School of Computer Science and Engineering, Anhui University of Science and Technology, Huainan 232001, China

⁴ Science and Technology on Electro-Optic Control Laboratory, Luoyang Institute of Electro-Optical Equipment of Avic, Luoyang 471000, China

⁵ Shanghai Key Lab for Trustworthy Computing, East China Normal University, Shanghai 200062, China

Sensors 2017, 17(5), 1045; https://doi.org/10.3390/s17051045 - 6 May 2017

Cited by 11 | Viewed by 4043

Abstract

Compared with the fixed fusion structure, the flexible fusion structure with mixed fusion methods has better adjustment performance for the complex air task network systems, and it can effectively help the system to achieve the goal under the given constraints. Because of the [...] Read more.

Compared with the fixed fusion structure, the flexible fusion structure with mixed fusion methods has better adjustment performance for the complex air task network systems, and it can effectively help the system to achieve the goal under the given constraints. Because of the time-varying situation of the task network system induced by moving nodes and non-cooperative target, and limitations such as communication bandwidth and measurement distance, it is necessary to dynamically adjust the system fusion structure including sensors and fusion methods in a given adjustment period. Aiming at this, this paper studies the design of a flexible fusion algorithm by using an optimization learning technology. The purpose is to dynamically determine the sensors’ numbers and the associated sensors to take part in the centralized and distributed fusion processes, respectively, herein termed sensor subsets selection. Firstly, two system performance indexes are introduced. Especially, the survivability index is presented and defined. Secondly, based on the two indexes and considering other conditions such as communication bandwidth and measurement distance, optimization models for both single target tracking and multi-target tracking are established. Correspondingly, solution steps are given for the two optimization models in detail. Simulation examples are demonstrated to validate the proposed algorithms. 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, 9064 KiB

Open AccessArticle

A Novel Method of Aircraft Detection Based on High-Resolution Panchromatic Optical Remote Sensing Images

by Wensheng Wang^1,2,*, Ting Nie^1,2, Tianjiao Fu¹, Jianyue Ren¹ and Longxu Jin¹

¹ Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China

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

Sensors 2017, 17(5), 1047; https://doi.org/10.3390/s17051047 - 6 May 2017

Cited by 19 | Viewed by 4752

Abstract

In target detection of optical remote sensing images, two main obstacles for aircraft target detection are how to extract the candidates in complex gray-scale-multi background and how to confirm the targets in case the target shapes are deformed, irregular or asymmetric, such as [...] Read more.

In target detection of optical remote sensing images, two main obstacles for aircraft target detection are how to extract the candidates in complex gray-scale-multi background and how to confirm the targets in case the target shapes are deformed, irregular or asymmetric, such as that caused by natural conditions (low signal-to-noise ratio, illumination condition or swaying photographing) and occlusion by surrounding objects (boarding bridge, equipment). To solve these issues, an improved active contours algorithm, namely region-scalable fitting energy based threshold (TRSF), and a corner-convex hull based segmentation algorithm (CCHS) are proposed in this paper. Firstly, the maximal variance between-cluster algorithm (Otsu’s algorithm) and region-scalable fitting energy (RSF) algorithm are combined to solve the difficulty of targets extraction in complex and gray-scale-multi backgrounds. Secondly, based on inherent shapes and prominent corners, aircrafts are divided into five fragments by utilizing convex hulls and Harris corner points. Furthermore, a series of new structure features, which describe the proportion of targets part in the fragment to the whole fragment and the proportion of fragment to the whole hull, are identified to judge whether the targets are true or not. Experimental results show that TRSF algorithm could improve extraction accuracy in complex background, and that it is faster than some traditional active contours algorithms. The CCHS is effective to suppress the detection difficulties caused by the irregular shape. Full article

(This article belongs to the Section Remote Sensors)

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16 pages, 8410 KiB

Open AccessArticle

Full-Field Calibration of Color Camera Chromatic Aberration using Absolute Phase Maps

by Xiaohong Liu¹, Shujun Huang¹, Zonghua Zhang^1,2,*

, Feng Gao²

and Xiangqian Jiang²

¹ School of Mechanical Engineering, Hebei University of Technology, Tianjin 300130, China

² Centre for Precision Technologies, University of Huddersfield, Huddersfield HD1 3DH, UK

Sensors 2017, 17(5), 1048; https://doi.org/10.3390/s17051048 - 6 May 2017

Cited by 15 | Viewed by 5426

Abstract

The refractive index of a lens varies for different wavelengths of light, and thus the same incident light with different wavelengths has different outgoing light. This characteristic of lenses causes images captured by a color camera to display chromatic aberration (CA), which seriously [...] Read more.

The refractive index of a lens varies for different wavelengths of light, and thus the same incident light with different wavelengths has different outgoing light. This characteristic of lenses causes images captured by a color camera to display chromatic aberration (CA), which seriously reduces image quality. Based on an analysis of the distribution of CA, a full-field calibration method based on absolute phase maps is proposed in this paper. Red, green, and blue closed sinusoidal fringe patterns are generated, consecutively displayed on an LCD (liquid crystal display), and captured by a color camera from the front viewpoint. The phase information of each color fringe is obtained using a four-step phase-shifting algorithm and optimum fringe number selection method. CA causes the unwrapped phase of the three channels to differ. These pixel deviations can be computed by comparing the unwrapped phase data of the red, blue, and green channels in polar coordinates. CA calibration is accomplished in Cartesian coordinates. The systematic errors introduced by the LCD are analyzed and corrected. Simulated results show the validity of the proposed method and experimental results demonstrate that the proposed full-field calibration method based on absolute phase maps will be useful for practical software-based CA calibration. Full article

(This article belongs to the Section Physical Sensors)

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36 pages, 7631 KiB

Open AccessArticle

Alternative Path Communication in Wide-Scale Cluster-Tree Wireless Sensor Networks Using Inactive Periods

by Erico Leão^1,2,*

, Carlos Montez³

, Ricardo Moraes⁴, Paulo Portugal² and Francisco Vasques²

¹ Department of Computing, Federal University of Piauí, 64049-550 Teresina, Brazil

² INEGI/INESC-TEC, Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal

³ Automation and Systems Department, Federal University of Santa Catarina, 88040-900 Florianópolis, Brazil

⁴ Department of Computing, Federal University of Santa Catarina, 88905-120 Araranguá, Brazil

Sensors 2017, 17(5), 1049; https://doi.org/10.3390/s17051049 - 6 May 2017

Cited by 8 | Viewed by 5494

Abstract

The IEEE 802.15.4/ZigBee cluster-tree topology is a suitable technology to deploy wide-scale Wireless Sensor Networks (WSNs). These networks are usually designed to support convergecast traffic, where all communication paths go through the PAN (Personal Area Network) coordinator. Nevertheless, peer-to-peer communication relationships may be [...] Read more.

The IEEE 802.15.4/ZigBee cluster-tree topology is a suitable technology to deploy wide-scale Wireless Sensor Networks (WSNs). These networks are usually designed to support convergecast traffic, where all communication paths go through the PAN (Personal Area Network) coordinator. Nevertheless, peer-to-peer communication relationships may be also required for different types of WSN applications. That is the typical case of sensor and actuator networks, where local control loops must be closed using a reduced number of communication hops. The use of communication schemes optimised just for the support of convergecast traffic may result in higher network congestion and in a potentially higher number of communication hops. Within this context, this paper proposes an Alternative-Route Definition (ARounD) communication scheme for WSNs. The underlying idea of ARounD is to setup alternative communication paths between specific source and destination nodes, avoiding congested cluster-tree paths. These alternative paths consider shorter inter-cluster paths, using a set of intermediate nodes to relay messages during their inactive periods in the cluster-tree network. Simulation results show that the ARounD communication scheme can significantly decrease the end-to-end communication delay, when compared to the use of standard cluster-tree communication schemes. Moreover, the ARounD communication scheme is able to reduce the network congestion around the PAN coordinator, enabling the reduction of the number of message drops due to queue overflows in the cluster-tree network. Full article

(This article belongs to the Section Sensor Networks)

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13 pages, 3384 KiB

Open AccessArticle

Wearable Contactless Respiration Sensor Based on Multi-Material Fibers Integrated into Textile

by Philippe Guay¹, Stepan Gorgutsa¹

, Sophie LaRochelle² and Younes Messaddeq^1,*

¹ Center for Optics, Photonics and Lasers (COPL), Department of Physics, Université Laval, Québec, QC G1V 0A6, Canada

² Department of Electrical and Computer Engineering, Université Laval, Québec, QC G1V 0A6, Canada

Sensors 2017, 17(5), 1050; https://doi.org/10.3390/s17051050 - 6 May 2017

Cited by 48 | Viewed by 23091

Abstract

In this paper, we report on a novel sensor for the contactless monitoring of the respiration rate, made from multi-material fibers arranged in the form of spiral antenna (2.45 GHz central frequency). High flexibility of the used composite metal-glass-polymer fibers permits their integration [...] Read more.

In this paper, we report on a novel sensor for the contactless monitoring of the respiration rate, made from multi-material fibers arranged in the form of spiral antenna (2.45 GHz central frequency). High flexibility of the used composite metal-glass-polymer fibers permits their integration into a cotton t-shirt without compromising comfort or restricting movement of the user. At the same time, change of the antenna geometry, due to the chest expansion and the displacement of the air volume in the lungs, is found to cause a significant shift of the antenna operational frequency, thus allowing respiration detection. In contrast with many current solutions, respiration is detected without attachment of the electrodes of any kind to the user’s body, neither direct contact of the fiber with the skin is required. Respiration patterns for two male volunteers were recorded with the help of a sensor prototype integrated into standard cotton t-shirt in sitting, standing, and lying scenarios. The typical measured frequency shift for the deep and shallow breathing was found to be in the range 120–200 MHz and 10–15 MHz, respectively. The same spiral fiber antenna is also shown to be suitable for short-range wireless communication, thus allowing respiration data transmission, for example, via the Bluetooth protocol, to mobile handheld devices. Full article

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

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17 pages, 1209 KiB

Open AccessArticle

Low-Latency and Energy-Efficient Data Preservation Mechanism in Low-Duty-Cycle Sensor Networks

by Chan Jiang^1,2,*, Tao-Shen Li^1,2, Jun-Bin Liang² and Heng Wu³

¹ School of Electronic and Information Engineering, South China University of Technology, Guangzhou 510641, China

² School of Computer, Electronics and Information, Guangxi University, Nanning 530004, China

³ Department of Computer Science, College of Engineering, Texas Tech University, Lubbock, TX 79409, USA

Sensors 2017, 17(5), 1051; https://doi.org/10.3390/s17051051 - 6 May 2017

Cited by 17 | Viewed by 4880

Abstract

Similar to traditional wireless sensor networks (WSN), the nodes only have limited memory and energy in low-duty-cycle sensor networks (LDC-WSN). However, different from WSN, the nodes in LDC-WSN often sleep most of their time to preserve their energies. The sleeping feature causes serious [...] Read more.

Similar to traditional wireless sensor networks (WSN), the nodes only have limited memory and energy in low-duty-cycle sensor networks (LDC-WSN). However, different from WSN, the nodes in LDC-WSN often sleep most of their time to preserve their energies. The sleeping feature causes serious data transmission delay. However, each source node that has sensed data needs to quickly disseminate its data to other nodes in the network for redundant storage. Otherwise, data would be lost due to its source node possibly being destroyed by outer forces in a harsh environment. The quick dissemination requirement produces a contradiction with the sleeping delay in the network. How to quickly disseminate all the source data to all the nodes with limited memory in the network for effective preservation is a challenging issue. In this paper, a low-latency and energy-efficient data preservation mechanism in LDC-WSN is proposed. The mechanism is totally distributed. The data can be disseminated to the network with low latency by using a revised probabilistic broadcasting mechanism, and then stored by the nodes with LT (Luby Transform) codes, which are a famous rateless erasure code. After the process of data dissemination and storage completes, some nodes may die due to being destroyed by outer forces. If a mobile sink enters the network at any time and from any place to collect the data, it can recover all of the source data by visiting a small portion of survived nodes in the network. Theoretical analyses and simulation results show that our mechanism outperforms existing mechanisms in the performances of data dissemination delay and energy efficiency. Full article

(This article belongs to the Special Issue Wireless Rechargeable Sensor Networks)

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19 pages, 875 KiB

Open AccessArticle

Spectrum Sensing Using Co-Prime Array Based Modulated Wideband Converter

by Wanghan Lv¹, Huali Wang² and Shanxiang Mu^1,*

¹ School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China

² College of Communications Engineering, PLA University of Science and Technology, Nanjing 210007,China

Sensors 2017, 17(5), 1052; https://doi.org/10.3390/s17051052 - 6 May 2017

Cited by 12 | Viewed by 4169

Abstract

As known to us all, it is challenging to monitor wideband signals in frequency domain due to the restriction of hardware. Several practical sampling schemes, such as multicoset sampling and the modulated wideband converter (MWC), have been proposed. In this work, a co-prime [...] Read more.

As known to us all, it is challenging to monitor wideband signals in frequency domain due to the restriction of hardware. Several practical sampling schemes, such as multicoset sampling and the modulated wideband converter (MWC), have been proposed. In this work, a co-prime array (CA) based modulated wideband converter (MWC) spectrum sensing method is suggested. Our proposed method has the same sampling principle as the MWC but has some advantages compared to MWC. Firstly, CA-based MWC is an array-based MWC system. Each sensor is usually corrupted by independent noise for an array system which can be used for noise averaging, while all channels in conventional MWC have the same receiving noise. Secondly, by incorporating the co-prime array, we can estimate the power spectrum of signal directly employing its second-order statistical properties. Moreover, the system minimal sampling rate can be reduced further because of the reduction of sampling channels. Simulation results show that our method has better performance than traditional methods. Full article

(This article belongs to the Special Issue Cognitive Radio Sensing and Sensor Networks)

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11 pages, 2677 KiB

Open AccessArticle

Characterizing Esophageal Cancerous Cells at Different Stages Using the Dielectrophoretic Impedance Measurement Method in a Microchip

by Hsiang-Chen Wang¹

, Ngoc-Viet Nguyen², Rui-Yi Lin² and Chun-Ping Jen^2,*

¹ Graduate Institute of Opto-Mechatronics, National Chung Cheng University, Chia-Yi 621, Taiwan

² Department of Mechanical Engineering, National Chung Cheng University, Chia-Yi 621, Taiwan

Sensors 2017, 17(5), 1053; https://doi.org/10.3390/s17051053 - 6 May 2017

Cited by 25 | Viewed by 5536

Abstract

Analysis of cancerous cells allows us to provide useful information for the early diagnosis of cancer and to monitor treatment progress. An approach based on electrical principles has recently become an attractive technique. This study presents a microdevice that utilizes a dielectrophoretic impedance [...] Read more.

Analysis of cancerous cells allows us to provide useful information for the early diagnosis of cancer and to monitor treatment progress. An approach based on electrical principles has recently become an attractive technique. This study presents a microdevice that utilizes a dielectrophoretic impedance measurement method for the identification of cancerous cells. The proposed biochip consists of circle-on-line microelectrodes that are patterned using a standard microfabrication processes. A sample of various cell concentrations was introduced in an open-top microchamber. The target cells were collectively concentrated between the microelectrodes using dielectrophoresis manipulation, and their electrical impedance properties were also measured. Different stages of human esophageal squamous cell carcinoma lines could be distinguished. This result is consistent with findings using hyperspectral imaging technology. Moreover, it was observed that the distinguishing characteristics change in response to the progression of cancer cell invasiveness by Raman spectroscopy. The device enables highly efficient cell collection and provides rapid, sensitive, and label-free electrical measurements of cancerous cells. Full article

(This article belongs to the Special Issue Micro and Nanofabrication Technologies for Biosensors)

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20 pages, 7093 KiB

Open AccessArticle

Inspection and Reconstruction of Metal-Roof Deformation under Wind Pressure Based on Bend Sensors

by Liman Yang^*, Langfu Cui, Yunhua Li^*

and Chao An

School of Automation Science and Electrical Engineering, Beihang University, XueYuan Road No. 37, HaiDian District, Beijing 100191, China

Sensors 2017, 17(5), 1054; https://doi.org/10.3390/s17051054 - 6 May 2017

Cited by 7 | Viewed by 5316

Abstract

Metal roof sheathings are widely employed in large-span buildings because of their light weight, high strength and corrosion resistance. However, their severe working environment may lead to deformation, leakage and wind-lift, etc. Thus, predicting these damages in advance and taking maintenance measures accordingly [...] Read more.

Metal roof sheathings are widely employed in large-span buildings because of their light weight, high strength and corrosion resistance. However, their severe working environment may lead to deformation, leakage and wind-lift, etc. Thus, predicting these damages in advance and taking maintenance measures accordingly has become important to avoid economic losses and personal injuries. Conventionally, the health monitoring of metal roofs mainly relies on manual inspection, which unavoidably compromises the working efficiency and cannot diagnose and predict possible failures in time. Thus, we proposed a novel damage monitoring scheme implemented by laying bend sensors on vital points of metal roofs to precisely monitor the deformation in real time. A fast reconstruction model based on improved Levy-type solution is established to estimate the overall deflection distribution from the measured data. A standing seam metal roof under wind pressure is modeled as an elastic thin plate with a uniform load and symmetrical boundaries. The superposition method and Levy solution are adopted to obtain the analytical model that can converge quickly through simplifying an infinite series. The truncation error of this model is further analyzed. Simulation and experiments are carried out. They show that the proposed model is in reasonable agreement with the experimental results. Full article

(This article belongs to the Special Issue Innovative Sensing Control Scheme for Advanced Materials)

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12 pages, 4223 KiB

Open AccessArticle

Highly Sensitive Sputtered ZnO:Ga Thin Films Integrated by a Simple Stencil Mask Process on Microsensor Platforms for Sub-ppm Acetaldehyde Detection

by Lionel Presmanes^1,*

, Yohann Thimont¹

, Audrey Chapelle², Frédéric Blanc², Chabane Talhi², Corine Bonningue¹, Antoine Barnabé¹, Philippe Menini² and Philippe Tailhades¹

¹ CIRIMAT, Université de Toulouse, CNRS, INPT, UPS, 118 Route de Narbonne, F-31062 Toulouse Cedex 9, France

² LAAS-CNRS, Université de Toulouse, UPS, INSA, 7 avenue du colonel Roche, F-31031 Toulouse, France

Sensors 2017, 17(5), 1055; https://doi.org/10.3390/s17051055 - 6 May 2017

Cited by 9 | Viewed by 5543

Abstract

The integration of a 50-nm-thick layer of an innovative sensitive material on microsensors has been developed based on silicon micro-hotplates. In this study, integration of ZnO:Ga via radio-frequency (RF) sputtering has been successfully combined with a low cost and reliable stencil mask technique [...] Read more.

The integration of a 50-nm-thick layer of an innovative sensitive material on microsensors has been developed based on silicon micro-hotplates. In this study, integration of ZnO:Ga via radio-frequency (RF) sputtering has been successfully combined with a low cost and reliable stencil mask technique to obtain repeatable sensing layers on top of interdigitated electrodes. The variation of the resistance of this n-type Ga-doped ZnO has been measured under sub-ppm traces (500 ppb) of acetaldehyde (C₂H₄O). Thanks to the microheater designed into a thin membrane, the generation of very rapid temperature variations (from room temperature to 550 °C in 25 ms) is possible, and a rapid cycled pulsed-temperature operating mode can be applied to the sensor. This approach reveals a strong improvement of sensing performances with a huge sensitivity between 10 and 1000, depending on the working pulsed-temperature level. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in France 2016)

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13 pages, 6870 KiB

Open AccessArticle

Inkjet-Printed Membrane for a Capacitive Acoustic Sensor: Development and Characterization Using Laser Vibrometer

by Rubaiyet Iftekharul Haque^1,*

, Erick Ogam², Patrick Benaben¹ and Xavier Boddaert^1,*

¹ Centre Microélectronique de Provence (CMP), École Nationale Supérieure des Mines de Saint-Étienne, 13541 Gardanne, France

² Laboratoire de Mécanique et d’Acoustique UPR7051 CNRS, 4 impasse Nikola Tesla, CS 40006, 13453 Marseille Cedex 13, France

Sensors 2017, 17(5), 1056; https://doi.org/10.3390/s17051056 - 6 May 2017

Cited by 11 | Viewed by 5542

Abstract

This paper describes the fabrication process and the method to determine the membrane tension and defects of an inkjet-printed circular diaphragm. The membrane tension is an important parameter to design and fabricate an acoustic sensor and resonator with the highest sensitivity and selectivity [...] Read more.

This paper describes the fabrication process and the method to determine the membrane tension and defects of an inkjet-printed circular diaphragm. The membrane tension is an important parameter to design and fabricate an acoustic sensor and resonator with the highest sensitivity and selectivity over a determined range of frequency. During this work, the diaphragms are fabricated by inkjet printing of conductive silver ink on pre-strained Mylar thin films, and the membrane tension is determined using the resonant frequency obtained from its measured surface velocity response to an acoustic excitation. The membrane is excited by an acoustic pressure generated by a loudspeaker, and its displacement (response) is acquired using a laser Doppler vibrometer (LDV). The response of the fabricated membrane demonstrates good correlation with the numerical result. However, the inkjet-printed membrane exhibits undesired peaks, which appeared to be due to defects at their boundaries as observed from the scanning mode of LDV. Full article

(This article belongs to the Special Issue 3D Printed Sensors)

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13 pages, 2282 KiB

Open AccessArticle

Smartphone-Based Escalator Recognition for the Visually Impaired

by Daiki Nakamura¹, Hotaka Takizawa^1,*

, Mayumi Aoyagi², Nobuo Ezaki³ and Shinji Mizuno⁴

¹ Department of Computer Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8573, Japan

² Aichi University of Education, 1 Hirosawa, Igaya, Kariya 448-8542, Japan

³ Toba National College of Maritime Technology, 1-1 Ikegami, Toba 517-8501, Japan

⁴ Aichi Institute of Technology, 1247 Yachigusa, Yakusa, Toyota 470-0392, Japan

Sensors 2017, 17(5), 1057; https://doi.org/10.3390/s17051057 - 6 May 2017

Cited by 10 | Viewed by 6220

Abstract

It is difficult for visually impaired individuals to recognize escalators in everyday environments. If the individuals ride on escalators in the wrong direction, they will stumble on the steps. This paper proposes a novel method to assist visually impaired individuals in finding available [...] Read more.

It is difficult for visually impaired individuals to recognize escalators in everyday environments. If the individuals ride on escalators in the wrong direction, they will stumble on the steps. This paper proposes a novel method to assist visually impaired individuals in finding available escalators by the use of smartphone cameras. Escalators are recognized by analyzing optical flows in video frames captured by the cameras, and auditory feedback is provided to the individuals. The proposed method was implemented on an Android smartphone and applied to actual escalator scenes. The experimental results demonstrate that the proposed method is promising for helping visually impaired individuals use escalators. Full article

(This article belongs to the Section Physical Sensors)

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15 pages, 4723 KiB

Open AccessArticle

A Generalized Chirp-Scaling Algorithm for Geosynchronous Orbit SAR Staring Observations

by Caipin Li^1,2

and Mingyi He^1,*

¹ School of Electronics and Information, Northwestern Polytechnical University, N 1, Dongxiang Rd, Xi’an 710129, China

² China Academy of Space Technology (Xi’an), Weiqu Street, Xi’an 710100, China

Sensors 2017, 17(5), 1058; https://doi.org/10.3390/s17051058 - 6 May 2017

Cited by 7 | Viewed by 3886

Abstract

Geosynchronous Orbit Synthetic Aperture Radar (GEO SAR) has recently received increasing attention due to its ability of performing staring observations of ground targets. However, GEO SAR staring observation has an ultra-long integration time that conventional frequency domain algorithms cannot handle because of the [...] Read more.

Geosynchronous Orbit Synthetic Aperture Radar (GEO SAR) has recently received increasing attention due to its ability of performing staring observations of ground targets. However, GEO SAR staring observation has an ultra-long integration time that conventional frequency domain algorithms cannot handle because of the inaccurately assumed slant range model and existing azimuth aliasing. To overcome this problem, this paper proposes an improved chirp-scaling algorithm that uses a fifth-order slant range model where considering the impact of the “stop and go” assumption to overcome the inaccuracy of the conventional slant model and a two-step processing method to remove azimuth aliasing. Furthermore, the expression of two-dimensional spectrum is deduced based on a series of reversion methods, leading to an improved chirp-scaling algorithm including a high-order-phase coupling function compensation, range and azimuth compression. The important innovations of this algorithm are implementation of a fifth-order order slant range model and removal of azimuth aliasing for GEO SAR staring observations. A simulation of an L-band GEO SAR with 1800 s integration time is used to demonstrate the validity and accuracy of this algorithm. Full article

(This article belongs to the Section Remote Sensors)

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23 pages, 904 KiB

Open AccessArticle

Vulnerability- and Diversity-Aware Anonymization of Personally Identifiable Information for Improving User Privacy and Utility of Publishing Data

by Abdul Majeed¹, Farman Ullah^2,† and Sungchang Lee^1,*

¹ School of Information and Electronics Engineering, Korea Aerospace University, Deogyang-gu, Goyang-si, Gyeonggi-do 412-791, Korea

² Innovergence Lab (NGN Lab), Korea Aerospace University, Hanggongdaehang-ro, Deokyang-gu, Goyang-si, Gyeonggi-do 412-791, Korea

^† Current address: Department of Electrical Engineering, COMSATS Institute of Information Technology, Attock 43600, Pakistan.

Sensors 2017, 17(5), 1059; https://doi.org/10.3390/s17051059 - 8 May 2017

Cited by 28 | Viewed by 8295

Abstract

Personally identifiable information (PII) affects individual privacy because PII combinations may yield unique identifications in published data. User PII such as age, race, gender, and zip code contain private information that may assist an adversary in determining the user to whom such information [...] Read more.

Personally identifiable information (PII) affects individual privacy because PII combinations may yield unique identifications in published data. User PII such as age, race, gender, and zip code contain private information that may assist an adversary in determining the user to whom such information relates. Each item of user PII reveals identity differently, and some types of PII are highly identity vulnerable. More vulnerable types of PII enable unique identification more easily, and their presence in published data increases privacy risks. Existing privacy models treat all types of PII equally from an identity revelation point of view, and they mainly focus on hiding user PII in a crowd of other users. Ignoring the identity vulnerability of each type of PII during anonymization is not an effective method of protecting user privacy in a fine-grained manner. This paper proposes a new anonymization scheme that considers the identity vulnerability of PII to effectively protect user privacy. Data generalization is performed adaptively based on the identity vulnerability of PII as well as diversity to anonymize data. This adaptive generalization effectively enables anonymous data, which protects user identity and private information disclosures while maximizing the utility of data for performing analyses and building classification models. Additionally, the proposed scheme has low computational overheads. The simulation results show the effectiveness of the scheme and verify the aforementioned claims. Full article

(This article belongs to the Special Issue Security and Privacy Challenges in Emerging Fog Computing)

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29 pages, 18907 KiB

Open AccessArticle

A Novel Real-Time Reference Key Frame Scan Matching Method

by Haytham Mohamed^1,*, Adel Moussa^1,2, Mohamed Elhabiby³, Naser El-Sheimy¹ and Abu Sesay⁴

¹ Department of Geomatics Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada

² Department of Electrical and Computer Engineering, Port-Said University, Port-Said 42526, Egypt

³ Public Works Department, Ain Shams University, Cairo 11566, Egypt

⁴ Department of Electrical and Computer Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada

Sensors 2017, 17(5), 1060; https://doi.org/10.3390/s17051060 - 7 May 2017

Cited by 16 | Viewed by 6288

Abstract

Unmanned aerial vehicles represent an effective technology for indoor search and rescue operations. Typically, most indoor missions’ environments would be unknown, unstructured, and/or dynamic. Navigation of UAVs in such environments is addressed by simultaneous localization and mapping approach using either local or global [...] Read more.

Unmanned aerial vehicles represent an effective technology for indoor search and rescue operations. Typically, most indoor missions’ environments would be unknown, unstructured, and/or dynamic. Navigation of UAVs in such environments is addressed by simultaneous localization and mapping approach using either local or global approaches. Both approaches suffer from accumulated errors and high processing time due to the iterative nature of the scan matching method. Moreover, point-to-point scan matching is prone to outlier association processes. This paper proposes a low-cost novel method for 2D real-time scan matching based on a reference key frame (RKF). RKF is a hybrid scan matching technique comprised of feature-to-feature and point-to-point approaches. This algorithm aims at mitigating errors accumulation using the key frame technique, which is inspired from video streaming broadcast process. The algorithm depends on the iterative closest point algorithm during the lack of linear features which is typically exhibited in unstructured environments. The algorithm switches back to the RKF once linear features are detected. To validate and evaluate the algorithm, the mapping performance and time consumption are compared with various algorithms in static and dynamic environments. The performance of the algorithm exhibits promising navigational, mapping results and very short computational time, that indicates the potential use of the new algorithm with real-time 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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22 pages, 14072 KiB

Open AccessArticle

Obstacle Detection and Avoidance System Based on Monocular Camera and Size Expansion Algorithm for UAVs

by Abdulla Al-Kaff^*,†,‡

, Fernando García^‡

, David Martín^‡

, Arturo De La Escalera^‡

and José María Armingol

¹ Intelligent Systems Lab, Universidad Carlos III de Madrid, Leganes, 28911 Madrid, Spain

^† Current address: Department of System Engineering and Automation, Avenida de la Universidad, 30, Leganes, 28911 Madrid, Spain.

^‡ These authors contributed equally to this work.

Sensors 2017, 17(5), 1061; https://doi.org/10.3390/s17051061 - 7 May 2017

Cited by 96 | Viewed by 15492

Abstract

One of the most challenging problems in the domain of autonomous aerial vehicles is the designing of a robust real-time obstacle detection and avoidance system. This problem is complex, especially for the micro and small aerial vehicles, that is due to the Size, [...] Read more.

One of the most challenging problems in the domain of autonomous aerial vehicles is the designing of a robust real-time obstacle detection and avoidance system. This problem is complex, especially for the micro and small aerial vehicles, that is due to the Size, Weight and Power (SWaP) constraints. Therefore, using lightweight sensors (i.e., Digital camera) can be the best choice comparing with other sensors; such as laser or radar.For real-time applications, different works are based on stereo cameras in order to obtain a 3D model of the obstacles, or to estimate their depth. Instead, in this paper, a method that mimics the human behavior of detecting the collision state of the approaching obstacles using monocular camera is proposed. The key of the proposed algorithm is to analyze the size changes of the detected feature points, combined with the expansion ratios of the convex hull constructed around the detected feature points from consecutive frames. During the Aerial Vehicle (UAV) motion, the detection algorithm estimates the changes in the size of the area of the approaching obstacles. First, the method detects the feature points of the obstacles, then extracts the obstacles that have the probability of getting close toward the UAV. Secondly, by comparing the area ratio of the obstacle and the position of the UAV, the method decides if the detected obstacle may cause a collision. Finally, by estimating the obstacle 2D position in the image and combining with the tracked waypoints, the UAV performs the avoidance maneuver. The proposed algorithm was evaluated by performing real indoor and outdoor flights, and the obtained results show the accuracy of the proposed algorithm compared with other related works. Full article

(This article belongs to the Special Issue UAV-Based Remote Sensing)

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12 pages, 2307 KiB

Open AccessArticle

Super-Resolution Reconstruction of High-Resolution Satellite ZY-3 TLC Images

by Lin Li¹

, Wei Wang¹, Heng Luo² and Shen Ying^1,*

¹ School of Resource and Environmental Sciences, Wuhan University, Wuhan 430079, China

² Geomatics Center of Guangxi, Guangxi Bureau of Surveying, Mapping and GeoInformation, Nanning 530023, China

Sensors 2017, 17(5), 1062; https://doi.org/10.3390/s17051062 - 7 May 2017

Cited by 21 | Viewed by 7155

Abstract

Super-resolution (SR) image reconstruction is a technique used to recover a high-resolution image using the cumulative information provided by several low-resolution images. With the help of SR techniques, satellite remotely sensed images can be combined to achieve a higher-resolution image, which is especially [...] Read more.

Super-resolution (SR) image reconstruction is a technique used to recover a high-resolution image using the cumulative information provided by several low-resolution images. With the help of SR techniques, satellite remotely sensed images can be combined to achieve a higher-resolution image, which is especially useful for a two- or three-line camera satellite, e.g., the ZY-3 high-resolution Three Line Camera (TLC) satellite. In this paper, we introduce the application of the SR reconstruction method, including motion estimation and the robust super-resolution technique, to ZY-3 TLC images. The results show that SR reconstruction can significantly improve both the resolution and image quality of ZY-3 TLC images. Full article

(This article belongs to the Special Issue Multi-Sensor Integration and Fusion)

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18 pages, 5738 KiB

Open AccessArticle

A Dual Conductance Sensor for Simultaneous Measurement of Void Fraction and Structure Velocity of Downward Two-Phase Flow in a Slightly Inclined Pipe

by Yeon-Gun Lee¹

, Woo-Youn Won¹, Bo-An Lee² and Sin Kim^3,*

¹ Department of Nuclear and Energy Engineering, Jeju National University, Jeju 63243, Korea

² Institute for Nuclear Science and Technology, Jeju National University, Jeju 63243, Korea

³ School of Energy Systems Engineering, Chung-Ang University, Seoul 06974, Korea

Sensors 2017, 17(5), 1063; https://doi.org/10.3390/s17051063 - 8 May 2017

Cited by 21 | Viewed by 5226

Abstract

In this study, a new and improved electrical conductance sensor is proposed for application not only to a horizontal pipe, but also an inclined one. The conductance sensor was designed to have a dual layer, each consisting of a three-electrode set to obtain [...] Read more.

In this study, a new and improved electrical conductance sensor is proposed for application not only to a horizontal pipe, but also an inclined one. The conductance sensor was designed to have a dual layer, each consisting of a three-electrode set to obtain two instantaneous conductance signals in turns, so that the area-averaged void fraction and structure velocity could be measured simultaneously. The optimum configuration of the electrodes was determined through numerical analysis, and the calibration curves for stratified and annular flow were obtained through a series of static experiments. The fabricated conductance sensor was applied to a 45 mm inner diameter U-shaped downward inclined pipe with an inclination angle of 3° under adiabatic air-water flow conditions. In the tests, the superficial velocities ranged from 0.1 to 3.0 m/s for water and from 0.1 to 18 m/s for air. The obtained mean void fraction and the structure velocity from the conductance sensor were validated against the measurement by the wire-mesh sensor and the cross-correlation technique for the visualized images, respectively. The results of the flow regime classification and the corresponding time series of the void fraction at a variety of flow velocities were also discussed. Full article

(This article belongs to the Section Physical Sensors)

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13 pages, 6956 KiB

Open AccessArticle

Electrical Properties of Cement-Based Composites with Carbon Nanotubes, Graphene, and Graphite Nanofibers

by Doo-Yeol Yoo¹, Ilhwan You² and Seung-Jung Lee^3,*

¹ Department of Architectural Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea

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

³ Future Strategy Center, Korea Railroad Research Institute, 176 Cheoldobangmulgwan-ro, Uiwang-si, Gyeonggi-do 16105, Korea

Sensors 2017, 17(5), 1064; https://doi.org/10.3390/s17051064 - 8 May 2017

Cited by 165 | Viewed by 8542

Abstract

This study was conducted to evaluate the effect of the carbon-based nanomaterial type on the electrical properties of cement paste. Three different nanomaterials, multi-walled carbon nanotubes (MWCNTs), graphite nanofibers (GNFs), and graphene (G), were incorporated into the cement paste at a volume fraction [...] Read more.

This study was conducted to evaluate the effect of the carbon-based nanomaterial type on the electrical properties of cement paste. Three different nanomaterials, multi-walled carbon nanotubes (MWCNTs), graphite nanofibers (GNFs), and graphene (G), were incorporated into the cement paste at a volume fraction of 1%. The self-sensing capacity of the cement composites was also investigated by comparing the compressive stress/strain behaviors by evaluating the fractional change of resistivity (FCR). The electrical resistivity of the plain cement paste was slightly reduced by adding 1 vol % GNFs and G, whereas a significant decrease of the resistivity was achieved by adding 1 vol % MWCNTs. At an identical volume fraction of 1%, the composites with MWCNTs provided the best self-sensing capacity with insignificant noise, followed by the composites containing GNFs and G. Therefore, the addition of MWCNTs was considered to be the most effective to improve the self-sensing capacity of the cement paste. Finally, the composites with 1 vol % MWCNTs exhibited a gauge factor of 113.2, which is much higher than commercially available strain gauges. Full article

(This article belongs to the Section Chemical Sensors)

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26 pages, 5742 KiB

Open AccessArticle

Convolutional Neural Network-Based Human Detection in Nighttime Images Using Visible Light Camera Sensors

by Jong Hyun Kim, Hyung Gil Hong 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(5), 1065; https://doi.org/10.3390/s17051065 - 8 May 2017

Cited by 67 | Viewed by 8070

Abstract

Because intelligent surveillance systems have recently undergone rapid growth, research on accurately detecting humans in videos captured at a long distance is growing in importance. The existing research using visible light cameras has mainly focused on methods of human detection for daytime hours [...] Read more.

Because intelligent surveillance systems have recently undergone rapid growth, research on accurately detecting humans in videos captured at a long distance is growing in importance. The existing research using visible light cameras has mainly focused on methods of human detection for daytime hours when there is outside light, but human detection during nighttime hours when there is no outside light is difficult. Thus, methods that employ additional near-infrared (NIR) illuminators and NIR cameras or thermal cameras have been used. However, in the case of NIR illuminators, there are limitations in terms of the illumination angle and distance. There are also difficulties because the illuminator power must be adaptively adjusted depending on whether the object is close or far away. In the case of thermal cameras, their cost is still high, which makes it difficult to install and use them in a variety of places. Because of this, research has been conducted on nighttime human detection using visible light cameras, but this has focused on objects at a short distance in an indoor environment or the use of video-based methods to capture multiple images and process them, which causes problems related to the increase in the processing time. To resolve these problems, this paper presents a method that uses a single image captured at night on a visible light camera to detect humans in a variety of environments based on a convolutional neural network. Experimental results using a self-constructed Dongguk night-time human detection database (DNHD-DB1) and two open databases (Korea advanced institute of science and technology (KAIST) and computer vision center (CVC) databases), as well as high-accuracy human detection in a variety of environments, show that the method has excellent performance compared to existing methods. Full article

(This article belongs to the Section Physical Sensors)

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14 pages, 5152 KiB

Open AccessArticle

Study on the Correlation between Humidity and Material Strains in Separable Micro Humidity Sensor Design

by Chih-Yuan Chang

Department of Civil Engineering, Feng Chia University, No. 100, Wenhwa Rd., Seatwen, Taichung 40724, Taiwan

Sensors 2017, 17(5), 1066; https://doi.org/10.3390/s17051066 - 8 May 2017

Cited by 8 | Viewed by 4412

Abstract

Incidents of injuries caused by tiles falling from building exterior walls are frequently reported in Taiwan. Humidity is an influential factor in tile deterioration but it is more difficult to measure the humidity inside a building structure than the humidity in an indoor [...] Read more.

Incidents of injuries caused by tiles falling from building exterior walls are frequently reported in Taiwan. Humidity is an influential factor in tile deterioration but it is more difficult to measure the humidity inside a building structure than the humidity in an indoor environment. Therefore, a separable microsensor was developed in this study to measure the humidity of the cement mortar layer with a thickness of 1.5–2 cm inside the external wall of a building. 3D printing technology is used to produce an encapsulation box that can protect the sensor from damage caused by the concrete and cement mortar. The sensor is proven in this study to be capable of measuring temperature and humidity simultaneously and the measurement results are then used to analyze the influence of humidity on external wall tile deterioration. Full article

(This article belongs to the Section Physical Sensors)

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13 pages, 3330 KiB

Open AccessArticle

Improvement of the Measurement Range and Temperature Characteristics of a Load Sensor Using a Quartz Crystal Resonator with All Crystal Layer Components

by Yuichi Murozaki^*, Shinya Sakuma and Fumihito Arai

Department of Micro-Nano Systems Engineering, Nagoya University, Nagoya 464-8603, Japan

Sensors 2017, 17(5), 1067; https://doi.org/10.3390/s17051067 - 8 May 2017

Cited by 26 | Viewed by 6768

Abstract

Monitoring multiple biosignals, such as heart rate, respiration cycle, and weight transitions, contributes to the health management of individuals. Specifically, it is possible to measure multiple biosignals using load information obtained through contact with the environment, such as a chair and bed, in [...] Read more.

Monitoring multiple biosignals, such as heart rate, respiration cycle, and weight transitions, contributes to the health management of individuals. Specifically, it is possible to measure multiple biosignals using load information obtained through contact with the environment, such as a chair and bed, in daily use. A wide-range load sensor is essential since load information contains multiple biosignals with various load ranges. In this study, a load sensor is presented by using a quartz crystal resonator (QCR) with a wide measurement range of 1.5 × 10⁶ (0.4 mN to 600 N), and its temperature characteristic of load is improved to −7 Hz/°C (−18 mN/°C). In order to improve the measurement range of the load, a design method of this sensor is proposed by restraining the buckling of QCR and by using a thinner QCR. The proposed sensor allows a higher allowable load with high sensitivity. The load sensor mainly consists of three layers, namely a QCR layer and two holding layers. As opposed to the conventional holding layer composed of silicon, quartz crystal is utilized for the holding layers to improve the temperature characteristic of the load sensor. In the study, multiple biosignals, such as weight and pulse, are detected by using a fabricated sensor. Full article

(This article belongs to the Section Physical Sensors)

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16 pages, 948 KiB

Open AccessArticle

Joint Smoothed l₀-Norm DOA Estimation Algorithm for Multiple Measurement Vectors in MIMO Radar

by Jing Liu^1,2, Weidong Zhou^1,* and Filbert H. Juwono³

¹ College of Automation, Harbin Engineering University, Harbin 150001, China

² School of Electrical, Electronic and Computer Engineering, The University of Western Australia, Perth 6009, Australia

³ Department of Electrical Engineering, Universitas Indonesia, Depok 16424, Indonesia

Sensors 2017, 17(5), 1068; https://doi.org/10.3390/s17051068 - 8 May 2017

Cited by 16 | Viewed by 5356

Abstract

Direction-of-arrival (DOA) estimation is usually confronted with a multiple measurement vector (MMV) case. In this paper, a novel fast sparse DOA estimation algorithm, named the joint smoothed

l_{0}

-norm algorithm, is proposed for multiple measurement vectors in multiple-input multiple-output (MIMO) radar. To [...] Read more.

Direction-of-arrival (DOA) estimation is usually confronted with a multiple measurement vector (MMV) case. In this paper, a novel fast sparse DOA estimation algorithm, named the joint smoothed

l_{0}

-norm algorithm, is proposed for multiple measurement vectors in multiple-input multiple-output (MIMO) radar. To eliminate the white or colored Gaussian noises, the new method first obtains a low-complexity high-order cumulants based data matrix. Then, the proposed algorithm designs a joint smoothed function tailored for the MMV case, based on which joint smoothed

l_{0}

-norm sparse representation framework is constructed. Finally, for the MMV-based joint smoothed function, the corresponding gradient-based sparse signal reconstruction is designed, thus the DOA estimation can be achieved. The proposed method is a fast sparse representation algorithm, which can solve the MMV problem and perform well for both white and colored Gaussian noises. The proposed joint algorithm is about two orders of magnitude faster than the

l_{1}

-norm minimization based methods, such as

l_{1}

-SVD (singular value decomposition), RV (real-valued)

l_{1}

-SVD and RV

l_{1}

-SRACV (sparse representation array covariance vectors), and achieves better DOA estimation performance. Full article

(This article belongs to the Section Physical Sensors)

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8 pages, 5676 KiB

Open AccessArticle

Simultaneous Detection of Static and Dynamic Signals by a Flexible Sensor Based on 3D Graphene

by Rongqing Xu^1,2,*, Di Wang¹, Hongchao Zhang³, Na Xie¹, Shan Lu⁴ and Ke Qu^1,*

¹ College of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China

² National Laboratory of Solid-State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, China

³ Department of Information Physics and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China

⁴ Shanghai Key Laboratory of Aerospace Intelligent Control Technology, Shanghai Aerospace Control Technology Institute, Shanghai 201109, China

Sensors 2017, 17(5), 1069; https://doi.org/10.3390/s17051069 - 8 May 2017

Cited by 17 | Viewed by 6484

Abstract

A flexible acoustic pressure sensor was developed based on the change in electrical resistance of three-dimensional (3D) graphene change under the acoustic waves action. The sensor was constructed by 3D graphene foam (GF) wrapped in flexible polydimethylsiloxane (PDMS). Tuning forks and human physiological [...] Read more.

A flexible acoustic pressure sensor was developed based on the change in electrical resistance of three-dimensional (3D) graphene change under the acoustic waves action. The sensor was constructed by 3D graphene foam (GF) wrapped in flexible polydimethylsiloxane (PDMS). Tuning forks and human physiological tests indicated that the acoustic pressure sensor can sensitively detect the deformation and the acoustic pressure in real time. The results are of significance to the development of graphene-based applications in the field of health monitoring, in vitro diagnostics, advanced therapies, and transient pressure detection. Full article

(This article belongs to the Special Issue Flexible Electronics and Sensors)

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18 pages, 7455 KiB

Open AccessArticle

A Method of Sky Ripple Residual Nonuniformity Reduction for a Cooled Infrared Imager and Hardware Implementation

by Yiyang Li

, Weiqi Jin^*, Shuo Li, Xu Zhang and Jin Zhu

School of Optoelectronics, Beijing Institute of Technology, Key Laboratory of Photo-electronic Imaging Technology and System, Ministry of Education of China, Beijing 100081, China

Sensors 2017, 17(5), 1070; https://doi.org/10.3390/s17051070 - 8 May 2017

Cited by 9 | Viewed by 4646

Abstract

Cooled infrared detector arrays always suffer from undesired ripple residual nonuniformity (RNU) in sky scene observations. The ripple residual nonuniformity seriously affects the imaging quality, especially for small target detection. It is difficult to eliminate it using the calibration-based techniques and the current [...] Read more.

Cooled infrared detector arrays always suffer from undesired ripple residual nonuniformity (RNU) in sky scene observations. The ripple residual nonuniformity seriously affects the imaging quality, especially for small target detection. It is difficult to eliminate it using the calibration-based techniques and the current scene-based nonuniformity algorithms. In this paper, we present a modified temporal high-pass nonuniformity correction algorithm using fuzzy scene classification. The fuzzy scene classification is designed to control the correction threshold so that the algorithm can remove ripple RNU without degrading the scene details. We test the algorithm on a real infrared sequence by comparing it to several well-established methods. The result shows that the algorithm has obvious advantages compared with the tested methods in terms of detail conservation and convergence speed for ripple RNU correction. Furthermore, we display our architecture with a prototype built on a Xilinx Virtex-5 XC5VLX50T field-programmable gate array (FPGA), which has two advantages: (1) low resources consumption; and (2) small hardware delay (less than 10 image rows). It has been successfully applied in an actual system. Full article

(This article belongs to the Special Issue Infrared Detectors)

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12 pages, 3035 KiB

Open AccessArticle

Compensating Unknown Time-Varying Delay in Opto-Electronic Platform Tracking Servo System

by Ruihong Xie^1,2,*, Tao Zhang², Jiaquan Li² and Ming Dai²

¹ Graduate University of Chinese Academy of Sciences, Beijing 100039, China

² Key Laboratory of Airborne Optical Imaging and Measurement, Changchun Institute of Optics, Fine Mechanics and Physics Chinese Academy of Sciences, Changchun 130033, China

Sensors 2017, 17(5), 1071; https://doi.org/10.3390/s17051071 - 9 May 2017

Cited by 6 | Viewed by 4009

Abstract

This paper investigates the problem of compensating miss-distance delay in opto-electronic platform tracking servo system. According to the characteristic of LOS (light-of-sight) motion, we setup the Markovian process model and compensate this unknown time-varying delay by feed-forward forecasting controller based on robust H∞ [...] Read more.

This paper investigates the problem of compensating miss-distance delay in opto-electronic platform tracking servo system. According to the characteristic of LOS (light-of-sight) motion, we setup the Markovian process model and compensate this unknown time-varying delay by feed-forward forecasting controller based on robust H∞ control. Finally, simulation based on double closed-loop PI (Proportion Integration) control system indicates that the proposed method is effective for compensating unknown time-varying delay. Tracking experiments on the opto-electronic platform indicate that RMS (root-mean-square) error is 1.253 mrad when tracking 10° 0.2 Hz signal. Full article

(This article belongs to the Section Physical Sensors)

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18 pages, 3731 KiB

Open AccessArticle

Compensation of PVT Variations in ToF Imagers with In-Pixel TDC

by Ion Vornicu^*, Ricardo Carmona-Galán

and Ángel Rodríguez-Vázquez

Instituto de Microelectrónica de Sevilla, IMSE-CNM (CSIC-Universidad de Sevilla), Avda. Américo Vespucio s/n, Parque Científico y Tecnológico de La Cartuja, Seville 41092, Spain

Sensors 2017, 17(5), 1072; https://doi.org/10.3390/s17051072 - 9 May 2017

Cited by 10 | Viewed by 5971

Abstract

The design of a direct time-of-flight complementary metal-oxide-semiconductor (CMOS) image sensor (dToF-CIS) based on a single-photon avalanche-diode (SPAD) array with an in-pixel time-to-digital converter (TDC) must contemplate system-level aspects that affect its overall performance. This paper provides a detailed analysis of the impact [...] Read more.

The design of a direct time-of-flight complementary metal-oxide-semiconductor (CMOS) image sensor (dToF-CIS) based on a single-photon avalanche-diode (SPAD) array with an in-pixel time-to-digital converter (TDC) must contemplate system-level aspects that affect its overall performance. This paper provides a detailed analysis of the impact of process parameters, voltage supply, and temperature (PVT) variations on the time bin of the TDC array. Moreover, the design and characterization of a global compensation loop is presented. It is based on a phase locked loop (PLL) that is integrated on-chip. The main building block of the PLL is a voltage-controlled ring-oscillator (VCRO) that is identical to the ones employed for the in-pixel TDCs. The reference voltage that drives the master VCRO is distributed to the voltage control inputs of the slave VCROs such that their multiphase outputs become invariant to PVT changes. These outputs act as time interpolators for the TDCs. Therefore the compensation scheme prevents the time bin of the TDCs from drifting over time due to the aforementioned factors. Moreover, the same scheme is used to program different time resolutions of the direct time-of-flight (ToF) imager aimed at 3D ranging or depth map imaging. Experimental results that validate the analysis are provided as well. The compensation loop proves to be remarkably effective. The spreading of the TDCs time bin is lowered from: (i) 20% down to 2.4% while the temperature ranges from 0 °C to 100 °C; (ii) 27% down to 0.27%, when the voltage supply changes within ±10% of the nominal value; (iii) 5.2 ps to 2 ps standard deviation over 30 sample chips, due to process parameters’ variation. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Spain 2016)

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13 pages, 2146 KiB

Open AccessArticle

Fabrication of a Novel Highly Sensitive and Selective Immunosensor for Botulinum Neurotoxin Serotype A Based on an Effective Platform of Electrosynthesized Gold Nanodendrites/Chitosan Nanoparticles

by Rahim Sorouri^1,*, Hasan Bagheri², Abbas Afkhami³ and Jafar Salimian²

¹ Department of Microbiology, Faculty of Medicine, Baqiyatallah University of Medical Sciences, Tehran 1435116471, Iran

² Chemical Injuries Research Center, Baqiyatallah University of Medical Sciences, Tehran 1435116471, Iran

³ Faculty of Chemistry, Bu-Ali Sina University, Hamedan 6517838695, Iran

Sensors 2017, 17(5), 1074; https://doi.org/10.3390/s17051074 - 9 May 2017

Cited by 29 | Viewed by 5456

Abstract

In this work, a novel nanocomposite consisting of electrosynthesized gold nanodendrites and chitosan nanoparticles (AuNDs/CSNPs) has been prepared to fabricate an impedimetric immunosensor based on a screen printed carbon electrode (SPCE) for the rapid and sensitive immunoassay of botulinum neurotoxin A (BoNT/A). BoNT/A [...] Read more.

In this work, a novel nanocomposite consisting of electrosynthesized gold nanodendrites and chitosan nanoparticles (AuNDs/CSNPs) has been prepared to fabricate an impedimetric immunosensor based on a screen printed carbon electrode (SPCE) for the rapid and sensitive immunoassay of botulinum neurotoxin A (BoNT/A). BoNT/A polyclonal antibody was immobilized on the nanocomposite-modified SPCE for the signal amplification. The structure of the prepared nanocomposite was investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The charge transfer resistance (R_CT) changes were used to detect BoNT/A as the specific immuno-interactions at the immunosensor surface that efficiently limited the electron transfer of Fe(CN)₆^3−/4− as a redox probe at pH = 7.4. A linear relationship was observed between the %∆R_CT and the concentration logarithm of BoNT/A within the range of 0.2 to 230 pg·mL⁻¹ with a detection limit (S/N = 3) of 0.15 pg·mL⁻¹. The practical applicability of the proposed sensor was examined by evaluating the detection of BoNT/A in milk and serum samples with satisfactory recoveries. Therefore, the prepared immunosensor holds great promise for the fast, simple and sensitive detection of BoNT/A in various real samples. Full article

(This article belongs to the Section Biosensors)

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19 pages, 8587 KiB

Open AccessArticle

Mechanics Based Tomography: A Preliminary Feasibility Study

by Yue Mei¹, Sicheng Wang², Xin Shen¹, Stephen Rabke¹ and Sevan Goenezen^1,*

¹ Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, USA

² Department of Mathematics, Texas A&M University, College Station, TX 77843, USA

Sensors 2017, 17(5), 1075; https://doi.org/10.3390/s17051075 - 9 May 2017

Cited by 18 | Viewed by 4924

Abstract

We present a non-destructive approach to sense inclusion objects embedded in a solid medium remotely from force sensors applied to the medium and boundary displacements that could be measured via a digital image correlation system using a set of cameras. We provide a [...] Read more.

We present a non-destructive approach to sense inclusion objects embedded in a solid medium remotely from force sensors applied to the medium and boundary displacements that could be measured via a digital image correlation system using a set of cameras. We provide a rationale and strategy to uniquely identify the heterogeneous sample composition based on stiffness (here, shear modulus) maps. The feasibility of this inversion scheme is tested with simulated experiments that could have clinical relevance in diagnostic imaging (e.g., tumor detection) or could be applied to engineering materials. No assumptions are made on the shape or stiffness quantity of the inclusions. We observe that the novel inversion method using solely boundary displacements and force measurements performs well in recovering the heterogeneous material/tissue composition that consists of one and two stiff inclusions embedded in a softer background material. Furthermore, the target shear modulus value for the stiffer inclusion region is underestimated and the inclusion size is overestimated when incomplete boundary displacements on some part of the boundary are utilized. For displacements measured on the entire boundary, the shear modulus reconstruction improves significantly. Additionally, we observe that with increasing number of displacement data sets utilized in solving the inverse problem, the quality of the mapped shear moduli improves. We also analyze the sensitivity of the shear modulus maps on the noise level varied between 0.1% and 5% white Gaussian noise in the boundary displacements, force and corresponding displacement indentation. Finally, a sensitivity analysis of the recovered shear moduli to the depth, stiffness and the shape of the stiff inclusion is performed. We conclude that this approach has potential as a novel imaging modality and refer to it as Mechanics Based Tomography (MBT). Full article

(This article belongs to the Special Issue Force and Pressure Based Sensing Medical Application)

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21 pages, 6067 KiB

Open AccessArticle

A Study of Pattern Prediction in the Monitoring Data of Earthen Ruins with the Internet of Things

by Yun Xiao¹, Xin Wang^1,2,*, Faezeh Eshragh², Xuanhong Wang³, Xiaojiang Chen¹ and Dingyi Fang¹

¹ School of Information Science and Technology, Northwest University, Xi’an 710021, China

² Department of Geomatics Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada

³ Department of Communication, Xi’an University of Posts & Telecommunications, Xi’an 710121, China

Sensors 2017, 17(5), 1076; https://doi.org/10.3390/s17051076 - 11 May 2017

Cited by 5 | Viewed by 3896

Abstract

An understanding of the changes of the rammed earth temperature of earthen ruins is important for protection of such ruins. To predict the rammed earth temperature pattern using the air temperature pattern of the monitoring data of earthen ruins, a pattern prediction method [...] Read more.

An understanding of the changes of the rammed earth temperature of earthen ruins is important for protection of such ruins. To predict the rammed earth temperature pattern using the air temperature pattern of the monitoring data of earthen ruins, a pattern prediction method based on interesting pattern mining and correlation, called PPER, is proposed in this paper. PPER first finds the interesting patterns in the air temperature sequence and the rammed earth temperature sequence. To reduce the processing time, two pruning rules and a new data structure based on an R-tree are also proposed. Correlation rules between the air temperature patterns and the rammed earth temperature patterns are then mined. The correlation rules are merged into predictive rules for the rammed earth temperature pattern. Experiments were conducted to show the accuracy of the presented method and the power of the pruning rules. Moreover, the Ming Dynasty Great Wall dataset was used to examine the algorithm, and six predictive rules from the air temperature to rammed earth temperature based on the interesting patterns were obtained, with the average hit rate reaching 89.8%. The PPER and predictive rules will be useful for rammed earth temperature prediction in protection of earthen ruins. Full article

(This article belongs to the Section Physical Sensors)

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12 pages, 4996 KiB

Open AccessArticle

Efficient Fluorescence Resonance Energy Transfer between Quantum Dots and Gold Nanoparticles Based on Porous Silicon Photonic Crystal for DNA Detection

by Hongyan Zhang¹

, Jie Lv² and Zhenhong Jia^3,*

¹ School of Physical Science and Technology, Xinjiang University, Urumqi 830046, China

² College of Resource and Environment science, Xinjiang University, Urumqi 830046, China

³ College of Information Science and Engineering, Xinjiang University, Urumqi 830046, China

Sensors 2017, 17(5), 1078; https://doi.org/10.3390/s17051078 - 10 May 2017

Cited by 45 | Viewed by 7224

Abstract

A novel assembled biosensor was prepared for detecting 16S rRNA, a small-size persistent specific for Actinobacteria. The mechanism of the porous silicon (PS) photonic crystal biosensor is based on the fluorescence resonance energy transfer (FRET) between quantum dots (QDs) and gold nanoparticles (AuNPs) [...] Read more.

A novel assembled biosensor was prepared for detecting 16S rRNA, a small-size persistent specific for Actinobacteria. The mechanism of the porous silicon (PS) photonic crystal biosensor is based on the fluorescence resonance energy transfer (FRET) between quantum dots (QDs) and gold nanoparticles (AuNPs) through DNA hybridization, where QDs act as an emission donor and AuNPs serve as a fluorescence quencher. Results showed that the photoluminescence (PL) intensity of PS photonic crystal was drastically increased when the QDs-conjugated probe DNA was adhered to the PS layer by surface modification using a standard cross-link chemistry method. The PL intensity of QDs was decreased when the addition of AuNPs-conjugated complementary 16S rRNA was dropped onto QDs-conjugated PS. Based on the analysis of different target DNA concentration, it was found that the decrease of the PL intensity showed a good linear relationship with complementary DNA concentration in a range from 0.25 to 10 μM, and the detection limit was 328.7 nM. Such an optical FRET biosensor functions on PS-based photonic crystal for DNA detection that differs from the traditional FRET, which is used only in liquid. This method will benefit the development of a new optical FRET label-free biosensor on Si substrate and has great potential in biochips based on integrated optical devices. Full article

(This article belongs to the Section Biosensors)

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11 pages, 3187 KiB

Open AccessArticle

GryphSens: A Smartphone-Based Portable Diagnostic Reader for the Rapid Detection of Progesterone in Milk

by Hyunwook Jang, Syed Rahin Ahmed and Suresh Neethirajan^*

BioNano Laboratory, School of Engineering, University of Guelph, Guelph, ON N1G 2W1, Canada

Sensors 2017, 17(5), 1079; https://doi.org/10.3390/s17051079 - 10 May 2017

Cited by 10 | Viewed by 7382

Abstract

Enzyme-linked immunosorbent assay (ELISA) is a popular assay technique for the detection and quantification of various biological substances due its high sensitivity and specificity. More often, it requires large and expensive laboratory instruments, which makes it difficult to conduct when the tests must [...] Read more.

Enzyme-linked immunosorbent assay (ELISA) is a popular assay technique for the detection and quantification of various biological substances due its high sensitivity and specificity. More often, it requires large and expensive laboratory instruments, which makes it difficult to conduct when the tests must be performed quickly at the point-of-care (POC). To increase portability and ease of use, we propose a portable diagnostic system based on a Raspberry Pi imaging sensor for the rapid detection of progesterone in milk samples. We designed, assembled, and tested a standalone portable diagnostic reader and validated it for progesterone detection against a standard ELISA assay using a commercial plate reader. The portable POC device yielded consistent results, regardless of differences in the cameras and flashlights between various smartphone devices. An Android application was built to provide front-end access to users, control the diagnostic reader, and display and store the progesterone measurement on the smartphone. The diagnostic reader takes images of the samples, reads the pixel values, processes the results, and presents the results on the handheld device. The proposed POC reader can perform to superior levels of performance as a plate reader, while adding the desirable qualities of portability and ease of use. Full article

(This article belongs to the Section Chemical Sensors)

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29 pages, 6064 KiB

Open AccessFeature PaperArticle

MERITXELL: The Multifrequency Experimental Radiometer with Interference Tracking for Experiments over Land and Littoral—Instrument Description, Calibration and Performance

by Jorge Querol^*

, José Miguel Tarongí, Giuseppe Forte, José Javier Gómez and Adriano Camps^*

Remote Sensing Lab (RSLab), Department of Signal Theory and Communications (TSC), Universitat Politècnica de Catalunya—BarcelonaTech (UPC), Jordi Girona 1-3, Campus Nord, D4 Building, 08034 Barcelona, Spain

Sensors 2017, 17(5), 1081; https://doi.org/10.3390/s17051081 - 10 May 2017

Cited by 2 | Viewed by 7076

Abstract

MERITXELL is a ground-based multisensor instrument that includes a multiband dual-polarization radiometer, a GNSS reflectometer, and several optical sensors. Its main goals are twofold: to test data fusion techniques, and to develop Radio-Frequency Interference (RFI) detection, localization and mitigation techniques. The former is [...] Read more.

MERITXELL is a ground-based multisensor instrument that includes a multiband dual-polarization radiometer, a GNSS reflectometer, and several optical sensors. Its main goals are twofold: to test data fusion techniques, and to develop Radio-Frequency Interference (RFI) detection, localization and mitigation techniques. The former is necessary to retrieve complementary data useful to develop geophysical models with improved accuracy, whereas the latter aims at solving one of the most important problems of microwave radiometry. This paper describes the hardware design, the instrument control architecture, the calibration of the radiometer, and several captures of RFI signals taken with MERITXELL in urban environment. The multiband radiometer has a dual linear polarization total-power radiometer topology, and it covers the L-, S-, C-, X-, K-, Ka-, and W-band. Its back-end stage is based on a spectrum analyzer structure which allows to perform real-time signal processing, while the rest of the sensors are controlled by a host computer where the off-line processing takes place. The calibration of the radiometer is performed using the hot-cold load procedure, together with the tipping curves technique in the case of the five upper frequency bands. Finally, some captures of RFI signals are shown for most of the radiometric bands under analysis, which evidence the problem of RFI in microwave radiometry, and the limitations they impose in external calibration. Full article

(This article belongs to the Special Issue Recent Innovative Microwave Remote Sensing Instrumentation for Land Surface Applications)

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14 pages, 6074 KiB

Open AccessArticle

Discontinuity Detection in the Shield Metal Arc Welding Process

by José Alberto Naves Cocota^1,*

, Gabriel Carvalho Garcia², Adilson Rodrigues Da Costa¹

, Milton Sérgio Fernandes De Lima³, Filipe Augusto Santos Rocha² and Gustavo Medeiros Freitas²

¹ School of Mines, Federal University of Ouro Preto (UFOP), Morro do Cruzeiro, 35400-000 Ouro Preto, Brazil

² Instituto Tecnológico Vale (ITV)—Avenida Juscelino Kubitschek, 31, Bauxita, 35400-000 Ouro Preto, Brazil

³ Institute for Advanced Studies (IEAv-CTA), 12228-970 São José dos Campos, SP, Brazil

Sensors 2017, 17(5), 1082; https://doi.org/10.3390/s17051082 - 10 May 2017

Cited by 9 | Viewed by 6407

Abstract

This work proposes a new methodology for the detection of discontinuities in the weld bead applied in Shielded Metal Arc Welding (SMAW) processes. The detection system is based on two sensors—a microphone and piezoelectric—that acquire acoustic emissions generated during the welding. The feature [...] Read more.

This work proposes a new methodology for the detection of discontinuities in the weld bead applied in Shielded Metal Arc Welding (SMAW) processes. The detection system is based on two sensors—a microphone and piezoelectric—that acquire acoustic emissions generated during the welding. The feature vectors extracted from the sensor dataset are used to construct classifier models. The approaches based on Artificial Neural Network (ANN) and Support Vector Machine (SVM) classifiers are able to identify with a high accuracy the three proposed weld bead classes: desirable weld bead, shrinkage cavity and burn through discontinuities. Experimental results illustrate the system’s high accuracy, greater than 90% for each class. A novel Hierarchical Support Vector Machine (HSVM) structure is proposed to make feasible the use of this system in industrial environments. This approach presented 96.6% overall accuracy. Given the simplicity of the equipment involved, this system can be applied in the metal transformation industries. Full article

(This article belongs to the Section Physical Sensors)

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18 pages, 4241 KiB

Open AccessArticle

Acquisition and Neural Network Prediction of 3D Deformable Object Shape Using a Kinect and a Force-Torque Sensor

by Bilal Tawbe^*,† and Ana-Maria Cretu^†

¹ Department of Computer Science and Engineering, Université du Québec en Outaouais, Gatineau, J8X 3X7 QC, Canada

^† This paper is an extended version our paper published in Tawbe, B.; Cretu, A.-M. Data-Driven Representation of Soft Deformable Objects Based on Force-Torque Data and 3D Vision Measurements. In Proceedings of the 3rd International Electronic Conference on Sensors and Applications, Online, 15–30 November 2016; Sciforum Electronic Conference Series; Volume 3, p. E006, doi:10.3390/ecsa-3-E006.

Sensors 2017, 17(5), 1083; https://doi.org/10.3390/s17051083 - 11 May 2017

Cited by 10 | Viewed by 5754

Abstract

The realistic representation of deformations is still an active area of research, especially for deformable objects whose behavior cannot be simply described in terms of elasticity parameters. This paper proposes a data-driven neural-network-based approach for capturing implicitly and predicting the deformations of an [...] Read more.

The realistic representation of deformations is still an active area of research, especially for deformable objects whose behavior cannot be simply described in terms of elasticity parameters. This paper proposes a data-driven neural-network-based approach for capturing implicitly and predicting the deformations of an object subject to external forces. Visual data, in the form of 3D point clouds gathered by a Kinect sensor, is collected over an object while forces are exerted by means of the probing tip of a force-torque sensor. A novel approach based on neural gas fitting is proposed to describe the particularities of a deformation over the selectively simplified 3D surface of the object, without requiring knowledge of the object material. An alignment procedure, a distance-based clustering, and inspiration from stratified sampling support this process. The resulting representation is denser in the region of the deformation (an average of 96.6% perceptual similarity with the collected data in the deformed area), while still preserving the object’s overall shape (86% similarity over the entire surface) and only using on average of 40% of the number of vertices in the mesh. A series of feedforward neural networks is then trained to predict the mapping between the force parameters characterizing the interaction with the object and the change in the object shape, as captured by the fitted neural gas nodes. This series of networks allows for the prediction of the deformation of an object when subject to unknown interactions. Full article

(This article belongs to the Special Issue Selected Papers from the 3rd International Electronic Conference on Sensors and Applications)

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51 pages, 946 KiB

Open AccessArticle

A Survey on an Energy-Efficient and Energy-Balanced Routing Protocol for Wireless Sensor Networks

by Olayinka O. Ogundile^1,* and Attahiru S. Alfa^1,2

¹ Department of Electrical, Electronic and Computer Engineering, University of Pretoria, Hatfield 0028, South Africa

² Electrical and Computer Engineering, University of Manitoba, Winnipeg, MB R3T 2N2, Canada

Sensors 2017, 17(5), 1084; https://doi.org/10.3390/s17051084 - 10 May 2017

Cited by 121 | Viewed by 8552

Abstract

Wireless sensor networks (WSNs) form an important part of industrial application. There has been growing interest in the potential use of WSNs in applications such as environment monitoring, disaster management, health care monitoring, intelligence surveillance and defence reconnaissance. In these applications, the sensor [...] Read more.

Wireless sensor networks (WSNs) form an important part of industrial application. There has been growing interest in the potential use of WSNs in applications such as environment monitoring, disaster management, health care monitoring, intelligence surveillance and defence reconnaissance. In these applications, the sensor nodes (SNs) are envisaged to be deployed in sizeable numbers in an outlying area, and it is quite difficult to replace these SNs after complete deployment in many scenarios. Therefore, as SNs are predominantly battery powered devices, the energy consumption of the nodes must be properly managed in order to prolong the network lifetime and functionality to a rational time. Different energy-efficient and energy-balanced routing protocols have been proposed in literature over the years. The energy-efficient routing protocols strive to increase the network lifetime by minimizing the energy consumption in each SN. On the other hand, the energy-balanced routing protocols protract the network lifetime by uniformly balancing the energy consumption among the nodes in the network. There have been various survey papers put forward by researchers to review the performance and classify the different energy-efficient routing protocols for WSNs. However, there seems to be no clear survey emphasizing the importance, concepts, and principles of load-balanced energy routing protocols for WSNs. In this paper, we provide a clear picture of both the energy-efficient and energy-balanced routing protocols for WSNs. More importantly, this paper presents an extensive survey of the different state-of-the-art energy-efficient and energy-balanced routing protocols. A taxonomy is introduced in this paper to classify the surveyed energy-efficient and energy-balanced routing protocols based on their proposed mode of communication towards the base station (BS). In addition, we classified these routing protocols based on the solution types or algorithms, and the input decision variables defined in the routing algorithm. The strengths and weaknesses of the choice of the decision variables used in the design of these energy-efficient and energy-balanced routing protocols are emphasised. Finally, we suggest possible research directions in order to optimize the energy consumption in sensor networks. Full article

(This article belongs to the Section Sensor Networks)

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16 pages, 9198 KiB

Open AccessArticle

Ultrasound Transmission Tomography for Detecting and Measuring Cylindrical Objects Embedded in Concrete

by Dalmay Lluveras Núñez¹, Miguel Ángel Molero-Armenta², Miguel Ángel García Izquierdo³, Margarita González Hernández^1,* and José Javier Anaya Velayos¹

¹ Instituto de Tecnologías Físicas y de la Información, ITEFI (CSIC), C/Serrano 144, 28006 Madrid, Spain

² Innerspec Technologies Europe, Av. Madrid km. 27.2, 28802 Alcalá de Henares, Spain

³ E.T.S.I. Telecomunicación, U.P.M. Av. Complutense 30, 28040 Madrid, Spain

Sensors 2017, 17(5), 1085; https://doi.org/10.3390/s17051085 - 10 May 2017

Cited by 18 | Viewed by 6880

Abstract

This study explores the feasibility of using transmission tomographic images based on attenuation measures in transmission to detect and estimate the most common materials that are embedded in concrete, reinforcements and natural and artificial voids. A limited set of concrete specimens have been [...] Read more.

This study explores the feasibility of using transmission tomographic images based on attenuation measures in transmission to detect and estimate the most common materials that are embedded in concrete, reinforcements and natural and artificial voids. A limited set of concrete specimens have been made in which cylindrical objects such as bars/tubes of steel, PVC and aluminium have been embedded to analyse the effect of size and material. The methodology and scope of this study is presented and numerical simulations are carried out to optimize the emitter-receiver configuration and to understand the complex physical propagation phenomena of ultrasonic signals that travel through concrete with embedded inclusions. Experimental tomographic images are obtained by using an ultrasonic tomographic system, which has the advantage of needing only two ultrasonic transducers. Both the software simulation tool and the tomographic inspection system are developed by the authors. The obtained results show that PVC tubes and steel bars of diameters higher than 19 mm and embedded in cylindrical specimens, can be detected and their sizes estimated using segmented tomographic images. Full article

(This article belongs to the Section Physical Sensors)

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16 pages, 3931 KiB

Open AccessArticle

Ambiguity Resolution for Phase-Based 3-D Source Localization under Fixed Uniform Circular Array

by Xin Chen, Zhen Liu^* and Xizhang Wei

School of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073, China

Sensors 2017, 17(5), 1086; https://doi.org/10.3390/s17051086 - 11 May 2017

Cited by 14 | Viewed by 5262

Abstract

Under fixed uniform circular array (UCA), 3-D parameter estimation of a source whose half-wavelength is smaller than the array aperture would suffer from a serious phase ambiguity problem, which also appears in a recently proposed phase-based algorithm. In this paper, by using the [...] Read more.

Under fixed uniform circular array (UCA), 3-D parameter estimation of a source whose half-wavelength is smaller than the array aperture would suffer from a serious phase ambiguity problem, which also appears in a recently proposed phase-based algorithm. In this paper, by using the centro-symmetry of UCA with an even number of sensors, the source’s angles and range can be decoupled and a novel algorithm named subarray grouping and ambiguity searching (SGAS) is addressed to resolve angle ambiguity. In the SGAS algorithm, each subarray formed by two couples of centro-symmetry sensors can obtain a batch of results under different ambiguities, and by searching the nearest value among subarrays, which is always corresponding to correct ambiguity, rough angle estimation with no ambiguity is realized. Then, the unambiguous angles are employed to resolve phase ambiguity in a phase-based 3-D parameter estimation algorithm, and the source’s range, as well as more precise angles, can be achieved. Moreover, to improve the practical performance of SGAS, the optimal structure of subarrays and subarray selection criteria are further investigated. Simulation results demonstrate the satisfying performance of the proposed method in 3-D source localization. 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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12 pages, 5694 KiB

Open AccessArticle

Sound Source Localization Using Non-Conformal Surface Sound Field Transformation Based on Spherical Harmonic Wave Decomposition

by Lanyue Zhang^1,2, Dandan Ding³, Desen Yang^1,2, Jia Wang^1,2 and Jie Shi^1,2,*

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

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

³ Guizhou Aerospace Institute of Measuring and Testing Technology, Guiyang 550009, China

Sensors 2017, 17(5), 1087; https://doi.org/10.3390/s17051087 - 10 May 2017

Cited by 5 | Viewed by 4902

Abstract

Spherical microphone arrays have been paid increasing attention for their ability to locate a sound source with arbitrary incident angle in three-dimensional space. Low-frequency sound sources are usually located by using spherical near-field acoustic holography. The reconstruction surface and holography surface are conformal [...] Read more.

Spherical microphone arrays have been paid increasing attention for their ability to locate a sound source with arbitrary incident angle in three-dimensional space. Low-frequency sound sources are usually located by using spherical near-field acoustic holography. The reconstruction surface and holography surface are conformal surfaces in the conventional sound field transformation based on generalized Fourier transform. When the sound source is on the cylindrical surface, it is difficult to locate by using spherical surface conformal transform. The non-conformal sound field transformation by making a transfer matrix based on spherical harmonic wave decomposition is proposed in this paper, which can achieve the transformation of a spherical surface into a cylindrical surface by using spherical array data. The theoretical expressions of the proposed method are deduced, and the performance of the method is simulated. Moreover, the experiment of sound source localization by using a spherical array with randomly and uniformly distributed elements is carried out. Results show that the non-conformal surface sound field transformation from a spherical surface to a cylindrical surface is realized by using the proposed method. The localization deviation is around 0.01 m, and the resolution is around 0.3 m. The application of the spherical array is extended, and the localization ability of the spherical array is improved. Full article

(This article belongs to the Section Physical Sensors)

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18 pages, 657 KiB

Open AccessArticle

An Interference Mitigation Scheme of Device-to-Device Communications for Sensor Networks Underlying LTE-A

by Jeehyeong Kim, Nzabanita Abdoul Karim and Sunghyun Cho^*

Department of Computer Science and Engineering, Hanyang University, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan, Gyeonggi-do 426-791, Korea

Sensors 2017, 17(5), 1088; https://doi.org/10.3390/s17051088 - 10 May 2017

Cited by 19 | Viewed by 5434

Abstract

Device-to-Device (D2D) communication technology has become a key factor in wireless sensor networks to form autonomous communication links among sensor nodes. Many research results for D2D have been presented to resolve different technical issues of D2D. Nevertheless, the previous works have not resolved [...] Read more.

Device-to-Device (D2D) communication technology has become a key factor in wireless sensor networks to form autonomous communication links among sensor nodes. Many research results for D2D have been presented to resolve different technical issues of D2D. Nevertheless, the previous works have not resolved the shortage of data rate and limited coverage of wireless sensor networks. Due to bandwidth shortages and limited communication coverage, 3rd Generation Partnership Project (3GPP) has introduced a new Device-to-Device (D2D) communication technique underlying cellular networks, which can improve spectral efficiencies by enabling the direct communication of devices in proximity without passing through enhanced-NodeB (eNB). However, to enable D2D communication in a cellular network presents a challenge with regard to radio resource management since D2D links reuse the uplink radio resources of cellular users and it can cause interference to the receiving channels of D2D user equipment (DUE). In this paper, a hybrid mechanism is proposed that uses Fractional Frequency Reuse (FFR) and Almost Blank Sub-frame (ABS) schemes to handle inter-cell interference caused by cellular user equipments (CUEs) to D2D receivers (DUE-Rxs), reusing the same resources at the cell edge area. In our case, DUE-Rxs are considered as victim nodes and CUEs as aggressor nodes, since our primary target is to minimize inter-cell interference in order to increase the signal to interference and noise ratio (SINR) of the target DUE-Rx at the cell edge area. The numerical results show that the interference level of the target D2D receiver (DUE-Rx) decreases significantly compared to the conventional FFR at the cell edge. In addition, the system throughput of the proposed scheme can be increased up to 60% compared to the conventional FFR. Full article

(This article belongs to the Section Sensor Networks)

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11 pages, 11820 KiB

Open AccessArticle

Vehicle Counting and Moving Direction Identification Based on Small-Aperture Microphone Array

by Xingshui Zu^1,2

, Shaojie Zhang³, Feng Guo^1,2

, Qin Zhao^1,2, Xin Zhang⁴, Xing You¹, Huawei Liu¹, Baoqing Li^1,*

and Xiaobing Yuan¹

¹ Science and Technology on Microsystem Laboratory, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 201800, China

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

³ School of Mechanical Engineering and Electronic Information, China University of Geosciences, Wuhan 430074, China

⁴ IBM-Research China Labotatory, Beijing 100094, China

Sensors 2017, 17(5), 1089; https://doi.org/10.3390/s17051089 - 10 May 2017

Cited by 16 | Viewed by 5186

Abstract

The varying trend of a moving vehicle’s angles provides much important intelligence for an unattended ground sensor (UGS) monitoring system. The present study investigates the capabilities of a small-aperture microphone array (SAMA) based system to identify the number and moving direction of vehicles [...] Read more.

The varying trend of a moving vehicle’s angles provides much important intelligence for an unattended ground sensor (UGS) monitoring system. The present study investigates the capabilities of a small-aperture microphone array (SAMA) based system to identify the number and moving direction of vehicles travelling on a previously established route. In this paper, a SAMA-based acoustic monitoring system, including the system hardware architecture and algorithm mechanism, is designed as a single node sensor for the application of UGS. The algorithm is built on the varying trend of a vehicle’s bearing angles around the closest point of approach (CPA). We demonstrate the effectiveness of our proposed method with our designed SAMA-based monitoring system in various experimental sites. The experimental results in harsh conditions validate the usefulness of our proposed UGS monitoring system. Full article

(This article belongs to the Special Issue Acoustic Sensing and Ultrasonic Drug Delivery)

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12 pages, 5192 KiB

Open AccessArticle

Radon Mitigation Approach in a Laboratory Measurement Room

by Patricia Blanco-Rodríguez^1,‡, Luis Alfonso Fernández-Serantes^2,‡, Alberto Otero-Pazos^2,‡

, José Luis Calvo-Rolle^2,*,†,‡

and Francisco Javier De Cos Juez^3,‡

¹ Department of Energy, University of Oviedo, Oviedo 33004, Spain

² Department of Industrial Engineering, Universidade da Coruña, Ferrol 15405, Spain

³ Department of Mines Exploitation and Prospecting, University of Oviedo, Oviedo 33004, Spain

^† Current address: Department of Industrial Engineering, Universidade da Coruña, 15405 Coruña, Spain.

^‡ These authors contributed equally to this work.

Sensors 2017, 17(5), 1090; https://doi.org/10.3390/s17051090 - 11 May 2017

Cited by 9 | Viewed by 5644

Abstract

Radon gas is the second leading cause of lung cancer, causing thousands of deaths annually. It can be a problem for people or animals in houses, workplaces, schools or any building. Therefore, its mitigation has become essential to avoid health problems and to [...] Read more.

Radon gas is the second leading cause of lung cancer, causing thousands of deaths annually. It can be a problem for people or animals in houses, workplaces, schools or any building. Therefore, its mitigation has become essential to avoid health problems and to prevent radon from interfering in radioactive measurements. This study describes the implementation of radon mitigation systems at a radioactivity laboratory in order to reduce interferences in the different works carried out. A large set of radon concentration samples is obtained from measurements at the laboratory. While several mitigation methods were taken into account, the final applied solution is explained in detail, obtaining thus very good results by reducing the radon concentration by 76%. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Spain 2017)

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13 pages, 3053 KiB

Open AccessArticle

Substrate Dependent Ad-Atom Migration on Graphene and the Impact on Electron-Beam Sculpting Functional Nanopores

by Kevin J. Freedman^1,2, Gaurav Goyal³, Chi Won Ahn⁴ and Min Jun Kim^5,*

¹ Joint Genome Institute, Lawrence Berkeley National Laboratory, Walnut Creek, CA 94598, USA

² Global Viral, 425 California St., San Francisco, CA 90104, USA

³ Quantum Biosystems, 1455 Adams Dr., Menlo Park, CA 94025, USA

⁴ Nano-Materials Laboratory, National Nanofab Center, Daejeon 305-806, Korea

⁵ Department of Mechanical Engineering, Southern Methodist University, Dallas, TX 75275, USA

Sensors 2017, 17(5), 1091; https://doi.org/10.3390/s17051091 - 10 May 2017

Cited by 2 | Viewed by 5601

Abstract

The use of atomically thin graphene for molecular sensing has attracted tremendous attention over the years and, in some instances, could displace the use of classical thin films. For nanopore sensing, graphene must be suspended over an aperture so that a single pore [...] Read more.

The use of atomically thin graphene for molecular sensing has attracted tremendous attention over the years and, in some instances, could displace the use of classical thin films. For nanopore sensing, graphene must be suspended over an aperture so that a single pore can be formed in the free-standing region. Nanopores are typically drilled using an electron beam (e-beam) which is tightly focused until a desired pore size is obtained. E-beam sculpting of graphene however is not just dependent on the ability to displace atoms but also the ability to hinder the migration of ad-atoms on the surface of graphene. Using relatively lower e-beam fluxes from a thermionic electron source, the C-atom knockout rate seems to be comparable to the rate of carbon ad-atom attraction and accumulation at the e-beam/graphene interface (i.e., R_knockout ≈ R_accumulation). Working at this unique regime has allowed the study of carbon ad-atom migration as well as the influence of various substrate materials on e-beam sculpting of graphene. We also show that this information was pivotal to fabricating functional graphene nanopores for studying DNA with increased spatial resolution which is attributed to atomically thin membranes. Full article

(This article belongs to the Special Issue Single-Molecule Sensing)

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44 pages, 2840 KiB

Open AccessArticle

A Formal Approach to the Selection by Minimum Error and Pattern Method for Sensor Data Loss Reduction in Unstable Wireless Sensor Network Communications

by Changhwa Kim^* and DongHyun Shin

Department of Computer Science and Engineering, Gangneung-Wonju National University, 150, Namwonro, Heungeop-myeon, Wonju-si, Gangwon-do 26403, Korea

Sensors 2017, 17(5), 1092; https://doi.org/10.3390/s17051092 - 12 May 2017

Cited by 4 | Viewed by 4203

Abstract

There are wireless networks in which typically communications are unsafe. Most terrestrial wireless sensor networks belong to this category of networks. Another example of an unsafe communication network is an underwater acoustic sensor network (UWASN). In UWASNs in particular, communication failures occur frequently [...] Read more.

There are wireless networks in which typically communications are unsafe. Most terrestrial wireless sensor networks belong to this category of networks. Another example of an unsafe communication network is an underwater acoustic sensor network (UWASN). In UWASNs in particular, communication failures occur frequently and the failure durations can range from seconds up to a few hours, days, or even weeks. These communication failures can cause data losses significant enough to seriously damage human life or property, depending on their application areas. In this paper, we propose a framework to reduce sensor data loss during communication failures and we present a formal approach to the Selection by Minimum Error and Pattern (SMEP) method that plays the most important role for the reduction in sensor data loss under the proposed framework. The SMEP method is compared with other methods to validate its effectiveness through experiments using real-field sensor data sets. Moreover, based on our experimental results and performance comparisons, the SMEP method has been validated to be better than others in terms of the average sensor data value error rate caused by sensor data loss. Full article

(This article belongs to the Section Sensor Networks)

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11 pages, 4187 KiB

Open AccessArticle

Fusion Based on Visible Light Positioning and Inertial Navigation Using Extended Kalman Filters

by Zhitian Li

, Lihui Feng^* and Aiying Yang^*

School of Optoelectronics, Beijing Institute of Technology, 5 S. Zhongguancun Street, Beijing 100081, China

Sensors 2017, 17(5), 1093; https://doi.org/10.3390/s17051093 - 11 May 2017

Cited by 36 | Viewed by 5677

Abstract

With the rapid development of smart technology, the need for location-based services (LBS) increases every day. Since classical positioning technology such as GPS cannot satisfy the needs of indoor positioning, new indoor positioning technologies, such as Bluetooth, Wi-Fi, and Visible light communication (VLC), [...] Read more.

With the rapid development of smart technology, the need for location-based services (LBS) increases every day. Since classical positioning technology such as GPS cannot satisfy the needs of indoor positioning, new indoor positioning technologies, such as Bluetooth, Wi-Fi, and Visible light communication (VLC), have already cut a figure. VLC positioning has been proposed because it has higher accuracy, costs less, and is easier to accomplish in comparison to the other indoor positioning technologies. However, the practicality of VLC positioning is limited since it is easily affected by multipath effects and the layout of LEDs. Thus, we propose a fusion positioning system based on extended Kalman filters, which can fuse the VLC position and the inertial navigation data. The accuracy of the fusion positioning system is in centimeters, which is better compared to the VLC-based positioning or inertial navigation alone. Furthermore, the fusion positioning system has high accuracy, saves energy, costs little, and is easy to install, making it a promising candidate for future indoor positioning applications. Full article

(This article belongs to the Section Physical Sensors)

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17 pages, 3860 KiB

Open AccessArticle

Autonomous Sensors for Measuring Continuously the Moisture and Salinity of a Porous Medium

by Xavier Chavanne^* and Jean-Pierre Frangi

Institut de Physique du Globe de Paris, University Paris Diderot, Sorbonne Paris Cité, UMR 7154 CNRS, Case postale 7011-F75205 Paris CEDEX 13, France

Sensors 2017, 17(5), 1094; https://doi.org/10.3390/s17051094 - 11 May 2017

Cited by 14 | Viewed by 4842

Abstract

The article describes a new field sensor to monitor continuously in situ moisture and salinity of a porous medium via measurements of its dielectric permittivity, conductivity and temperature. It intends to overcome difficulties and biases encountered with sensors based on the same sensitivity [...] Read more.

The article describes a new field sensor to monitor continuously in situ moisture and salinity of a porous medium via measurements of its dielectric permittivity, conductivity and temperature. It intends to overcome difficulties and biases encountered with sensors based on the same sensitivity principle. Permittivity and conductivity are determined simultaneously by a self-balanced bridge, which measures directly the admittance of sensor electrodes in medium. All electric biases are reduced and their residuals taken into account by a physical model of the instrument, calibrated against reference fluids. Geometry electrode is optimized to obtain a well representative sample of the medium. The sensor also permits acquiring a large amount of data at high frequency (six points every hour, and even more) and to access it rapidly, even in real time, owing to autonomy capabilities and wireless communication. Ongoing developments intend to simplify and standardize present sensors. Results of field trials of prototypes in different environments are presented. Full article

(This article belongs to the Special Issue Humidity Sensors)

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23 pages, 1923 KiB

Open AccessArticle

A Case Study of Improving Yield Prediction and Sulfur Deficiency Detection Using Optical Sensors and Relationship of Historical Potato Yield with Weather Data in Maine

by Lakesh K. Sharma^1,*, Sukhwinder K. Bali^1,*, James D. Dwyer¹, Andrew B. Plant² and Arnab Bhowmik³

¹ Department of Cooperative Extension, University of Maine, 57 Houlton Rd, Presque Isle, ME 04769, USA

² Maine Potato Board, 744 Main Street, Suite 1, Presque Isle, ME 04769, USA

³ Department of Ecosystem Science and Management, 248 Ag Sciences and Industrial Building, Pennsylvania State University, University Park, PA 16802, USA

Sensors 2017, 17(5), 1095; https://doi.org/10.3390/s17051095 - 11 May 2017

Cited by 39 | Viewed by 6776

Abstract

In Maine, potato yield is consistent, 38 t·ha⁻¹, for last 10 years except 2016 (44 t·ha⁻¹) which confirms that increasing the yield and quality of potatoes with current fertilization practices is difficult; hence, new or improvised agronomic methods are [...] Read more.

In Maine, potato yield is consistent, 38 t·ha⁻¹, for last 10 years except 2016 (44 t·ha⁻¹) which confirms that increasing the yield and quality of potatoes with current fertilization practices is difficult; hence, new or improvised agronomic methods are needed to meet with producers and industry requirements. Normalized difference vegetative index (NDVI) sensors have shown promise in regulating N as an in season application; however, using late N may stretch out the maturation stage. The purpose of the research was to test Trimble GreenSeeker^® (TGS) and Holland Scientific Crop Circle™ ACS-430 (HCCACS-430) wavebands to predict potato yield, before the second hilling (6–8 leaf stage). Ammonium sulfate, S containing N fertilizer, is not advised to be applied on acidic soils but accounts for 60–70% fertilizer in Maine’s acidic soils; therefore, sensors are used on sulfur deficient site to produce sensor-bound S application guidelines before recommending non-S-bearing N sources. Two study sites investigated for this research include an S deficient site and a regular spot with two kinds of soils. Six N treatments, with both calcium ammonium nitrate and ammonium nitrate, under a randomized complete block design with four replications, were applied at planting. NDVI readings from both sensors were obtained at V8 leaf stages (8 leaf per plant) before the second hilling. Both sensors predict N and S deficiencies with a strong interaction with an average coefficient of correlation (r²) ~45. However, HCCACS-430 was observed to be more virtuous than TGS. The correlation between NDVI (from both sensors) and the potato yield improved using proprietor-proxy leaf area index (PPLAI) from HCCACS-430, e.g., r² value of TGS at Easton site improve from 48 to 60. Weather data affected marketable potato yield (MPY) significantly from south to north in Maine, especially precipitation variations that could be employed in the N recommendations at planting and in season application. This case study addresses a substantial need to revise potato N recommendations at planting and develop possible in season N recommendation using ground based active optical (GBAO) sensors. Full article

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19 pages, 8673 KiB

Open AccessArticle

Optical Sensing to Determine Tomato Plant Spacing for Precise Agrochemical Application: Two Scenarios

by Jorge Martínez-Guanter¹

, Miguel Garrido-Izard²

, Constantino Valero²

, David C. Slaughter³ and Manuel Pérez-Ruiz^1,*

¹ Aerospace Engineering and Fluid Mechanics Department, University of Seville, 41013 Seville, Spain

² Laboratorio de Propiedades Físicas (LPF_TAGRALIA), Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain

³ Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, USA

Sensors 2017, 17(5), 1096; https://doi.org/10.3390/s17051096 - 11 May 2017

Cited by 13 | Viewed by 6725

Abstract

The feasibility of automated individual crop plant care in vegetable crop fields has increased, resulting in improved efficiency and economic benefits. A systems-based approach is a key feature in the engineering design of mechanization that incorporates precision sensing techniques. The objective of this [...] Read more.

The feasibility of automated individual crop plant care in vegetable crop fields has increased, resulting in improved efficiency and economic benefits. A systems-based approach is a key feature in the engineering design of mechanization that incorporates precision sensing techniques. The objective of this study was to design new sensing capabilities to measure crop plant spacing under different test conditions (California, USA and Andalucía, Spain). For this study, three different types of optical sensors were used: an optical light-beam sensor (880 nm), a Light Detection and Ranging (LiDAR) sensor (905 nm), and an RGB camera. Field trials were conducted on newly transplanted tomato plants, using an encoder as a local reference system. Test results achieved a 98% accuracy in detection using light-beam sensors while a 96% accuracy on plant detections was achieved in the best of replications using LiDAR. These results can contribute to the decision-making regarding the use of these sensors by machinery manufacturers. This could lead to an advance in the physical or chemical weed control on row crops, allowing significant reductions or even elimination of hand-weeding tasks. Full article

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

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11 pages, 3640 KiB

Open AccessArticle

A Blade Tip Timing Method Based on a Microwave Sensor

by Jilong Zhang¹, Fajie Duan^1,*, Guangyue Niu¹, Jiajia Jiang¹

and Jie Li²

¹ State Key Laboratory of Precision Measuring Technology and Instruments; Tianjin University, Tianjin 300072, China

² China Gas Turbine Establishment; Chengdu 610500, China

Sensors 2017, 17(5), 1097; https://doi.org/10.3390/s17051097 - 11 May 2017

Cited by 51 | Viewed by 9012

Abstract

Blade tip timing is an effective method for blade vibration measurements in turbomachinery. This method is increasing in popularity because it is non-intrusive and has several advantages over the conventional strain gauge method. Different kinds of sensors have been developed for blade tip [...] Read more.

Blade tip timing is an effective method for blade vibration measurements in turbomachinery. This method is increasing in popularity because it is non-intrusive and has several advantages over the conventional strain gauge method. Different kinds of sensors have been developed for blade tip timing, including optical, eddy current and capacitance sensors. However, these sensors are unsuitable in environments with contaminants or high temperatures. Microwave sensors offer a promising potential solution to overcome these limitations. In this article, a microwave sensor-based blade tip timing measurement system is proposed. A patch antenna probe is used to transmit and receive the microwave signals. The signal model and process method is analyzed. Zero intermediate frequency structure is employed to maintain timing accuracy and dynamic performance, and the received signal can also be used to measure tip clearance. The timing method uses the rising and falling edges of the signal and an auto-gain control circuit to reduce the effect of tip clearance change. To validate the accuracy of the system, it is compared experimentally with a fiber optic tip timing system. The results show that the microwave tip timing system achieves good accuracy. Full article

(This article belongs to the Section Physical Sensors)

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17 pages, 8672 KiB

Open AccessArticle

Measuring Tree Properties and Responses Using Low-Cost Accelerometers

by Tim Van Emmerik^1,*

, Susan Steele-Dunne¹, Rolf Hut¹, Pierre Gentine², Marceau Guerin², Rafael S. Oliveira³, Jim Wagner⁴, John Selker⁵ and Nick Van de Giesen¹

¹ Water Resources Section, Delft University of Technology, Delft 2628 CN, The Netherlands

² Department of Earth and Environmental Engineering, Columbia University, New York, NY 10027, USA

³ Department of Plant Biology, Institute of Biology, University of Campinas, Campinas, SP 13083-862, Brazil

⁴ Oregon Research Electronics, Tangent, OR 97389, USA

⁵ Department of Biological and Ecological Engineering, Oregon State University, Corvallis, OR 97331, USA

Sensors 2017, 17(5), 1098; https://doi.org/10.3390/s17051098 - 11 May 2017

Cited by 40 | Viewed by 10380

Abstract

Trees play a crucial role in the water, carbon and nitrogen cycle on local, regional and global scales. Understanding the exchange of momentum, heat, water, and CO

_{2}

between trees and the atmosphere is important to assess the impact of drought, deforestation and [...] Read more.

Trees play a crucial role in the water, carbon and nitrogen cycle on local, regional and global scales. Understanding the exchange of momentum, heat, water, and CO

_{2}

between trees and the atmosphere is important to assess the impact of drought, deforestation and climate change. Unfortunately, ground measurements of tree properties such as mass and canopy interception of precipitation are often expensive or difficult due to challenging environments. This paper aims to demonstrate the concept of using robust and affordable accelerometers to measure tree properties and responses. Tree sway is dependent on mass, canopy structure, drag coefficient, and wind forcing. By measuring tree acceleration, we can relate the tree motion to external forcing (e.g., wind, precipitation and related canopy interception) and tree physical properties (e.g., mass, elasticity). Using five months of acceleration data of 19 trees in the Brazilian Amazon, we show that the frequency spectrum of tree sway is related to mass, canopy interception of precipitation, and canopy–atmosphere turbulent exchange. Full article

(This article belongs to the Section Physical Sensors)

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15 pages, 6438 KiB

Open AccessArticle

A Vision-Aided 3D Path Teaching Method before Narrow Butt Joint Welding

by Jinle Zeng

, Baohua Chang

, Dong Du^*, Guodong Peng, Shuhe Chang, Yuxiang Hong

, Li Wang and Jiguo Shan

Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China

Sensors 2017, 17(5), 1099; https://doi.org/10.3390/s17051099 - 11 May 2017

Cited by 34 | Viewed by 6406

Abstract

For better welding quality, accurate path teaching for actuators must be achieved before welding. Due to machining errors, assembly errors, deformations, etc., the actual groove position may be different from the predetermined path. Therefore, it is significant to recognize the actual groove position [...] Read more.

For better welding quality, accurate path teaching for actuators must be achieved before welding. Due to machining errors, assembly errors, deformations, etc., the actual groove position may be different from the predetermined path. Therefore, it is significant to recognize the actual groove position using machine vision methods and perform an accurate path teaching process. However, during the teaching process of a narrow butt joint, the existing machine vision methods may fail because of poor adaptability, low resolution, and lack of 3D information. This paper proposes a 3D path teaching method for narrow butt joint welding. This method obtains two kinds of visual information nearly at the same time, namely 2D pixel coordinates of the groove in uniform lighting condition and 3D point cloud data of the workpiece surface in cross-line laser lighting condition. The 3D position and pose between the welding torch and groove can be calculated after information fusion. The image resolution can reach 12.5 μm. Experiments are carried out at an actuator speed of 2300 mm/min and groove width of less than 0.1 mm. The results show that this method is suitable for groove recognition before narrow butt joint welding and can be applied in path teaching fields of 3D complex components. Full article

(This article belongs to the Section Physical Sensors)

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14 pages, 377 KiB

Open AccessArticle

A Human Activity Recognition System Based on Dynamic Clustering of Skeleton Data

by Alessandro Manzi^*

, Paolo Dario and Filippo Cavallo

The BioRobotics Institute, Scuola Superiore Sant’Anna, Viale Rinaldo Piaggio, 34, 56026 Pontedera (PI), Italy

Sensors 2017, 17(5), 1100; https://doi.org/10.3390/s17051100 - 11 May 2017

Cited by 51 | Viewed by 7736

Abstract

Human activity recognition is an important area in computer vision, with its wide range of applications including ambient assisted living. In this paper, an activity recognition system based on skeleton data extracted from a depth camera is presented. The system makes use of [...] Read more.

Human activity recognition is an important area in computer vision, with its wide range of applications including ambient assisted living. In this paper, an activity recognition system based on skeleton data extracted from a depth camera is presented. The system makes use of machine learning techniques to classify the actions that are described with a set of a few basic postures. The training phase creates several models related to the number of clustered postures by means of a multiclass Support Vector Machine (SVM), trained with Sequential Minimal Optimization (SMO). The classification phase adopts the X-means algorithm to find the optimal number of clusters dynamically. The contribution of the paper is twofold. The first aim is to perform activity recognition employing features based on a small number of informative postures, extracted independently from each activity instance; secondly, it aims to assess the minimum number of frames needed for an adequate classification. The system is evaluated on two publicly available datasets, the Cornell Activity Dataset (CAD-60) and the Telecommunication Systems Team (TST) Fall detection dataset. The number of clusters needed to model each instance ranges from two to four elements. The proposed approach reaches excellent performances using only about 4 s of input data (~100 frames) and outperforms the state of the art when it uses approximately 500 frames on the CAD-60 dataset. The results are promising for the test in real context. Full article

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

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15 pages, 7170 KiB

Open AccessArticle

An Automatic Localization Algorithm for Ultrasound Breast Tumors Based on Human Visual Mechanism

by Yuting Xie, Ke Chen and Jiangli Lin^*

Department of Biomedical Engineering, Sichuan University, Chengdu 610065, China

Sensors 2017, 17(5), 1101; https://doi.org/10.3390/s17051101 - 11 May 2017

Cited by 15 | Viewed by 6952

Abstract

Human visual mechanisms (HVMs) can quickly localize the most salient object in natural images, but it is ineffective at localizing tumors in ultrasound breast images. In this paper, we research the characteristics of tumors, develop a classic HVM and propose a novel auto-localization [...] Read more.

Human visual mechanisms (HVMs) can quickly localize the most salient object in natural images, but it is ineffective at localizing tumors in ultrasound breast images. In this paper, we research the characteristics of tumors, develop a classic HVM and propose a novel auto-localization method. Comparing to surrounding areas, tumors have higher global and local contrast. In this method, intensity, blackness ratio and superpixel contrast features are combined to compute a saliency map, in which a Winner Take All algorithm is used to localize the most salient region, which is represented by a circle. The results show that the proposed method can successfully avoid the interference caused by background areas of low echo and high intensity. The method has been tested on 400 ultrasound breast images, among which 376 images succeed in localization. This means this method has a high accuracy of 94.00%, indicating its good performance in real-life applications. Full article

(This article belongs to the Special Issue Acoustic Sensing and Ultrasonic Drug Delivery)

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13 pages, 1418 KiB

Open AccessArticle

Detection of Soil Nitrogen Using Near Infrared Sensors Based on Soil Pretreatment and Algorithms

by Pengcheng Nie^1,2, Tao Dong¹

, Yong He^1,*

and Fangfang Qu¹

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

² State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310058, China

Sensors 2017, 17(5), 1102; https://doi.org/10.3390/s17051102 - 11 May 2017

Cited by 59 | Viewed by 9732

Abstract

Soil nitrogen content is one of the important growth nutrient parameters of crops. It is a prerequisite for scientific fertilization to accurately grasp soil nutrient information in precision agriculture. The information about nutrients such as nitrogen in the soil can be obtained quickly [...] Read more.

Soil nitrogen content is one of the important growth nutrient parameters of crops. It is a prerequisite for scientific fertilization to accurately grasp soil nutrient information in precision agriculture. The information about nutrients such as nitrogen in the soil can be obtained quickly by using a near-infrared sensor. The data can be analyzed in the detection process, which is nondestructive and non-polluting. In order to investigate the effect of soil pretreatment on nitrogen content by near infrared sensor, 16 nitrogen concentrations were mixed with soil and the soil samples were divided into three groups with different pretreatment. The first group of soil samples with strict pretreatment were dried, ground, sieved and pressed. The second group of soil samples were dried and ground. The third group of soil samples were simply dried. Three linear different modeling methods are used to analyze the spectrum, including partial least squares (PLS), uninformative variable elimination (UVE), competitive adaptive reweighted algorithm (CARS). The model of nonlinear partial least squares which supports vector machine (LS-SVM) is also used to analyze the soil reflectance spectrum. The results show that the soil samples with strict pretreatment have the best accuracy in predicting nitrogen content by near-infrared sensor, and the pretreatment method is suitable for practical application. Full article

(This article belongs to the Special Issue Sensors for Biomedical, Environmental and Food Monitoring Applications)

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12 pages, 5456 KiB

Open AccessArticle

Operating Point Self-Regulator for Giant Magneto-Impedance Magnetic Sensor

by Han Zhou, Zhongming Pan^* and Dasha Zhang

College of Mechatronics Engineering and Automation, National University of Defense Technology, Changsha 410073, China

Sensors 2017, 17(5), 1103; https://doi.org/10.3390/s17051103 - 11 May 2017

Cited by 9 | Viewed by 5937

Abstract

The giant magneto-impedance (GMI) magnetic sensor based on the amorphous wire has been believed to be tiny dimensions, high sensitivity, quick response, and small power consumption. This kind of sensor is usually working under a bias magnetic field that is called the sensor’s [...] Read more.

The giant magneto-impedance (GMI) magnetic sensor based on the amorphous wire has been believed to be tiny dimensions, high sensitivity, quick response, and small power consumption. This kind of sensor is usually working under a bias magnetic field that is called the sensor’s operating point. However, the changes in direction and intensity of the external magnetic field, or the changes in sensing direction and position of the sensor, will lead to fluctuations in operating point when the sensor is working without any magnetic shield. In this work, a GMI sensor based on the operating point self-regulator is designed to overcome the problem. The regulator is based on the compensated feedback control that can maintain the operating point of a GMI sensor in a uniform position. With the regulator, the GMI sensor exhibits a stable sensitivity regardless of the external magnetic field. In comparison with the former work, the developed operating point regulator can improve the accuracy and stability of the operating point and therefore decrease the noise and disturbances that are introduced into the GMI sensor by the previous self-regulation system. Full article

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

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20 pages, 473 KiB

Open AccessArticle

Low-Cost Nested-MIMO Array for Large-Scale Wireless Sensor Applications

by Duo Zhang^1,*

, Wen Wu¹, Dagang Fang¹, Wenqin Wang² and Can Cui¹

¹ Ministerial Key Laboratory of JGMT, School of Electronic Engineering and Optoelectronic Technology, Nanjing University of Science and Technology, Nanjing 210094, China

² School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China

Sensors 2017, 17(5), 1105; https://doi.org/10.3390/s17051105 - 12 May 2017

Cited by 1 | Viewed by 5208

Abstract

In modern communication and radar applications, large-scale sensor arrays have increasingly been used to improve the performance of a system. However, the hardware cost and circuit power consumption scale linearly with the number of sensors, which makes the whole system expensive and power-hungry. [...] Read more.

In modern communication and radar applications, large-scale sensor arrays have increasingly been used to improve the performance of a system. However, the hardware cost and circuit power consumption scale linearly with the number of sensors, which makes the whole system expensive and power-hungry. This paper presents a low-cost nested multiple-input multiple-output (MIMO) array, which is capable of providing

O (2 N^{2})

degrees of freedom (DOF) with

O (N)

physical sensors. The sensor locations of the proposed array have closed-form expressions. Thus, the aperture size and number of DOF can be predicted as a function of the total number of sensors. Additionally, with the help of time-sequence-phase-weighting (TSPW) technology, only one receiver channel is required for sampling the signals received by all of the sensors, which is conducive to reducing the hardware cost and power consumption. Numerical simulation results demonstrate the effectiveness and superiority of the proposed array. 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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12 pages, 4042 KiB

Open AccessArticle

An Improved Design of the Spiral-Coil EMAT for Enhancing the Signal Amplitude

by Xiaojuan Jia, Qi Ouyang^* and Xinglan Zhang

Institute of Smart Engineering, School of Automation, Chongqing University, Chongqing 400044, China

Sensors 2017, 17(5), 1106; https://doi.org/10.3390/s17051106 - 12 May 2017

Cited by 28 | Viewed by 7336

Abstract

The low energy transition efficiency of electromagnetic ultrasonic transducer (EMAT) is a common problem in practical application. For the purpose of enhancing the amplitude of the received signal, an improved double-coil bulk wave EMAT is proposed for the thickness measurement of metallic block. [...] Read more.

The low energy transition efficiency of electromagnetic ultrasonic transducer (EMAT) is a common problem in practical application. For the purpose of enhancing the amplitude of the received signal, an improved double-coil bulk wave EMAT is proposed for the thickness measurement of metallic block. This new configuration of magnets consists of a solid cylindrical magnet and a ring-shaped magnet encircling the outer side of the solid cylindrical one. A double-coil was applied instead of a single spiral-coil. Numerical simulations were performed to analyze and optimize the proposed configuration of the EMAT by the 2-D axisymmetric finite element model (FEM). The experiment effectively verifies the rationality of the new configuration and the feasibility of improving the signal strength. Full article

(This article belongs to the Section Physical Sensors)

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13 pages, 1780 KiB

Open AccessArticle

Power Allocation Based on Data Classification in Wireless Sensor Networks

by Houlian Wang^1,† and Gongbo Zhou^1,2,*,†

¹ School of Mechanical and Electrical Engineering, China University of Mining & Technology, Xuzhou 221116, China

² Jiangsu Key Laboratory of Mine Mechanical and Electrical Equipment, China University of Mining & Technology, Xuzhou 221116, China

^† These authors contributed equally to this work.

Sensors 2017, 17(5), 1107; https://doi.org/10.3390/s17051107 - 12 May 2017

Cited by 9 | Viewed by 4611

Abstract

Limited node energy in wireless sensor networks is a crucial factor which affects the monitoring of equipment operation and working conditions in coal mines. In addition, due to heterogeneous nodes and different data acquisition rates, the number of arriving packets in a queue [...] Read more.

Limited node energy in wireless sensor networks is a crucial factor which affects the monitoring of equipment operation and working conditions in coal mines. In addition, due to heterogeneous nodes and different data acquisition rates, the number of arriving packets in a queue network can differ, which may lead to some queue lengths reaching the maximum value earlier compared with others. In order to tackle these two problems, an optimal power allocation strategy based on classified data is proposed in this paper. Arriving data is classified into dissimilar classes depending on the number of arriving packets. The problem is formulated as a Lyapunov drift optimization with the objective of minimizing the weight sum of average power consumption and average data class. As a result, a suboptimal distributed algorithm without any knowledge of system statistics is presented. The simulations, conducted in the perfect channel state information (CSI) case and the imperfect CSI case, reveal that the utility can be pushed arbitrarily close to optimal by increasing the parameter V, but with a corresponding growth in the average delay, and that other tunable parameters W and the classification method in the interior of utility function can trade power optimality for increased average data class. The above results show that data in a high class has priorities to be processed than data in a low class, and energy consumption can be minimized in this resource allocation strategy. Full article

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

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19 pages, 1200 KiB

Open AccessArticle

Effective Social Relationship Measurement and Cluster Based Routing in Mobile Opportunistic Networks

by Feng Zeng^1,*

, Nan Zhao¹ and Wenjia Li^2,*

¹ School of Software, Central South University, Changsha 410083, China

² Department of Computer Science, New York Institute of Technology, New York, NY 10023, USA

Sensors 2017, 17(5), 1109; https://doi.org/10.3390/s17051109 - 12 May 2017

Cited by 21 | Viewed by 5064

Abstract

In mobile opportunistic networks, the social relationship among nodes has an important impact on data transmission efficiency. Motivated by the strong share ability of “circles of friends” in communication networks such as Facebook, Twitter, Wechat and so on, we take a real-life example [...] Read more.

In mobile opportunistic networks, the social relationship among nodes has an important impact on data transmission efficiency. Motivated by the strong share ability of “circles of friends” in communication networks such as Facebook, Twitter, Wechat and so on, we take a real-life example to show that social relationships among nodes consist of explicit and implicit parts. The explicit part comes from direct contact among nodes, and the implicit part can be measured through the “circles of friends”. We present the definitions of explicit and implicit social relationships between two nodes, adaptive weights of explicit and implicit parts are given according to the contact feature of nodes, and the distributed mechanism is designed to construct the “circles of friends” of nodes, which is used for the calculation of the implicit part of social relationship between nodes. Based on effective measurement of social relationships, we propose a social-based clustering and routing scheme, in which each node selects the nodes with close social relationships to form a local cluster, and the self-control method is used to keep all cluster members always having close relationships with each other. A cluster-based message forwarding mechanism is designed for opportunistic routing, in which each node only forwards the copy of the message to nodes with the destination node as a member of the local cluster. Simulation results show that the proposed social-based clustering and routing outperforms the other classic routing algorithms. Full article

(This article belongs to the Special Issue New Advances in Identification, Information & Knowledge in the Internet of Things)

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15 pages, 8015 KiB

Open AccessArticle

Development of Data Registration and Fusion Methods for Measurement of Ultra-Precision Freeform Surfaces

by Ling Bao Kong¹, Ming Jun Ren^2,*

and Min Xu¹

¹ Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing, Fudan University, Shanghai 200433, China

² Institute of Robotics, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

Sensors 2017, 17(5), 1110; https://doi.org/10.3390/s17051110 - 12 May 2017

Cited by 6 | Viewed by 5243

Abstract

The measurement of ultra-precision freeform surfaces commonly requires several datasets from different sensors to realize holistic measurements with high efficiency. The effectiveness of the technology heavily depends on the quality of the data registration and fusion in the measurement process. This paper presents [...] Read more.

The measurement of ultra-precision freeform surfaces commonly requires several datasets from different sensors to realize holistic measurements with high efficiency. The effectiveness of the technology heavily depends on the quality of the data registration and fusion in the measurement process. This paper presents methods and algorithms to address these issues. An intrinsic feature pattern is proposed to represent the geometry of the measured datasets so that the registration of the datasets in 3D space is casted as a feature pattern registration problem in a 2D plane. The accuracy of the overlapping area is further improved by developing a Gaussian process based data fusion method with full consideration of the associated uncertainties in the measured datasets. Experimental studies are undertaken to examine the effectiveness of the proposed method. The study should contribute to the high precision and efficient measurement of ultra-precision freeform surfaces on multi-sensor systems. Full article

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

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19 pages, 7753 KiB

Open AccessArticle

Sound Power Estimation for Beam and Plate Structures Using Polyvinylidene Fluoride Films as Sensors

by Qibo Mao^1,2,*

and Haibing Zhong³

¹ School of Mechanical Engineering, Yangzhou University, Yangzhou 225127, China

² School of Aircraft Engineering, Nanchang Hang Kong University, Nanchang 330063, China

³ Kuang-Chi Advanced Institute of Technology, Shenzhen 518000, China

Sensors 2017, 17(5), 1111; https://doi.org/10.3390/s17051111 - 16 May 2017

Cited by 10 | Viewed by 4487

Abstract

The theory for calculation and/or measurement of sound power based on the classical velocity-based radiation mode (V-mode) approach is well established for planar structures. However, the current V-mode theory is limited in scope in that it can only be applied to conventional motion [...] Read more.

The theory for calculation and/or measurement of sound power based on the classical velocity-based radiation mode (V-mode) approach is well established for planar structures. However, the current V-mode theory is limited in scope in that it can only be applied to conventional motion sensors (i.e., accelerometers). In this study, in order to estimate the sound power of vibrating beam and plate structure by using polyvinylidene fluoride (PVDF) films as sensors, a PVDF-based radiation mode (C-mode) approach concept is introduced to determine the sound power radiation from the output signals of PVDF films of the vibrating structure. The proposed method is a hybrid of vibration measurement and numerical calculation of C-modes. The proposed C-mode approach has the following advantages: (1) compared to conventional motion sensors, the PVDF films are lightweight, flexible, and low-cost; (2) there is no need for special measuring environments, since the proposed method does not require the measurement of sound fields; (3) In low frequency range (typically with dimensionless frequency kl < 4), the radiation efficiencies of the C-modes fall off very rapidly with increasing mode order, furthermore, the shapes of the C-modes remain almost unchanged, which means that the computation load can be significantly reduced due to the fact only the first few dominant C-modes are involved in the low frequency range. Numerical simulations and experimental investigations were carried out to verify the accuracy and efficiency of the proposed method. Full article

(This article belongs to the Special Issue Acoustic Sensing and Ultrasonic Drug Delivery)

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13 pages, 8701 KiB

Open AccessArticle

Photosensor-Based Latency Measurement System for Head-Mounted Displays

by Min-Woo Seo¹, Song-Woo Choi¹, Sang-Lyn Lee², Eui-Yeol Oh², Jong-Sang Baek² and Suk-Ju Kang^1,*

¹ Department of Electronic Engineering, Sogang University, Seoul 04107, Korea

² LG Display, Paju 10845, Korea

Sensors 2017, 17(5), 1112; https://doi.org/10.3390/s17051112 - 15 May 2017

Cited by 19 | Viewed by 7541

Abstract

In this paper, a photosensor-based latency measurement system for head-mounted displays (HMDs) is proposed. The motion-to-photon latency is the greatest reason for motion sickness and dizziness felt by users when wearing an HMD system. Therefore, a measurement system is required to accurately measure [...] Read more.

In this paper, a photosensor-based latency measurement system for head-mounted displays (HMDs) is proposed. The motion-to-photon latency is the greatest reason for motion sickness and dizziness felt by users when wearing an HMD system. Therefore, a measurement system is required to accurately measure and analyze the latency to reduce these problems. The existing measurement system does not consider the actual physical movement in humans, and its accuracy is also very low. However, the proposed system considers the physical head movement and is highly accurate. Specifically, it consists of a head position model-based rotary platform, pixel luminance change detector, and signal analysis and calculation modules. Using these modules, the proposed system can exactly measure the latency, which is the time difference between the physical movement for a user and the luminance change of an output image. In the experiment using a commercial HMD, the latency was measured to be up to 47.05 ms. In addition, the measured latency increased up to 381.17 ms when increasing the rendering workload in the HMD. Full article

(This article belongs to the Section Physical Sensors)

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21 pages, 5125 KiB

Open AccessArticle

Easy and Fast Reconstruction of a 3D Avatar with an RGB-D Sensor

by Aihua Mao^*, Hong Zhang, Yuxin Liu, Yinglong Zheng, Guiqing Li and Guoqiang Han

School of Computer Science & Engineering, South China University of Technology, Guangzhou 510006, China

Sensors 2017, 17(5), 1113; https://doi.org/10.3390/s17051113 - 12 May 2017

Cited by 18 | Viewed by 9148

Abstract

This paper proposes a new easy and fast 3D avatar reconstruction method using an RGB-D sensor. Users can easily implement human body scanning and modeling just with a personal computer and a single RGB-D sensor such as a Microsoft Kinect within a small [...] Read more.

This paper proposes a new easy and fast 3D avatar reconstruction method using an RGB-D sensor. Users can easily implement human body scanning and modeling just with a personal computer and a single RGB-D sensor such as a Microsoft Kinect within a small workspace in their home or office. To make the reconstruction of 3D avatars easy and fast, a new data capture strategy is proposed for efficient human body scanning, which captures only 18 frames from six views with a close scanning distance to fully cover the body; meanwhile, efficient alignment algorithms are presented to locally align the data frames in the single view and then globally align them in multi-views based on pairwise correspondence. In this method, we do not adopt shape priors or subdivision tools to synthesize the model, which helps to reduce modeling complexity. Experimental results indicate that this method can obtain accurate reconstructed 3D avatar models, and the running performance is faster than that of similar work. This research offers a useful tool for the manufacturers to quickly and economically create 3D avatars for products design, entertainment and online shopping. Full article

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

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17 pages, 4138 KiB

Open AccessArticle

Multilook SAR Image Segmentation with an Unknown Number of Clusters Using a Gamma Mixture Model and Hierarchical Clustering

by Quanhua Zhao^*, Xiaoli Li and Yu Li

Institute for Remote Sensing Science and Application, School of Geomatics, Liaoning Technical University, Fuxin 123000, China

Sensors 2017, 17(5), 1114; https://doi.org/10.3390/s17051114 - 12 May 2017

Cited by 10 | Viewed by 4786

Abstract

This paper presents a novel multilook SAR image segmentation algorithm with an unknown number of clusters. Firstly, the marginal probability distribution for a given SAR image is defined by a Gamma mixture model (GaMM), in which the number of components corresponds to the [...] Read more.

This paper presents a novel multilook SAR image segmentation algorithm with an unknown number of clusters. Firstly, the marginal probability distribution for a given SAR image is defined by a Gamma mixture model (GaMM), in which the number of components corresponds to the number of homogeneous regions needed to segment and the spatial relationship among neighboring pixels is characterized by a Markov Random Field (MRF) defined by the weighting coefficients of components in GaMM. During the algorithm iteration procedure, the number of clusters is gradually reduced by merging two components until they are equal to one. For each fixed number of clusters, the parameters of GaMM are estimated and the optimal segmentation result corresponding to the number is obtained by maximizing the marginal probability. Finally, the number of clusters with minimum global energy defined as the negative logarithm of marginal probability is indicated as the expected number of clusters with the homogeneous regions needed to be segmented, and the corresponding segmentation result is considered as the final optimal one. The experimental results from the proposed and comparing algorithms for simulated and real multilook SAR images show that the proposed algorithm can find the real number of clusters and obtain more accurate segmentation results simultaneously. Full article

(This article belongs to the Special Issue Earth Observation for Biodiversity and Ecosystem Services: Remote Sensing Data Handling and Analysis)

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25 pages, 947 KiB

Open AccessArticle

Wireless Sensor Network-Based Service Provisioning by a Brokering Platform

by Luis Guijarro¹

, Vicent Pla¹

, Jose R. Vidal^1,*, Maurizio Naldi² and Toktam Mahmoodi³

¹ Institute ITACA, Universitat Politècnica de València, 46022 València, Spain

² Dipartimento di Ingegneria Civile e Ingegneria Informatica, University of Rome Tor Vergata, 00173 Roma, Italy

³ Center of Telecommunications Research, King’s College London, London WC2R 2LS, UK

Sensors 2017, 17(5), 1115; https://doi.org/10.3390/s17051115 - 12 May 2017

Cited by 10 | Viewed by 4725

Abstract

This paper proposes a business model for providing services based on the Internet of Things through a platform that intermediates between human users and Wireless Sensor Networks (WSNs). The platform seeks to maximize its profit through posting both the price charged to each [...] Read more.

This paper proposes a business model for providing services based on the Internet of Things through a platform that intermediates between human users and Wireless Sensor Networks (WSNs). The platform seeks to maximize its profit through posting both the price charged to each user and the price paid to each WSN. A complete analysis of the profit maximization problem is performed in this paper. We show that the service provider maximizes its profit by incentivizing all users and all Wireless Sensor Infrastructure Providers (WSIPs) to join the platform. This is true not only when the number of users is high, but also when it is moderate, provided that the costs that the users bear do not trespass a cost ceiling. This cost ceiling depends on the number of WSIPs, on the value of the intrinsic value of the service and on the externality that the WSIP has on the user utility. Full article

(This article belongs to the Special Issue New Advances in Identification, Information & Knowledge in the Internet of Things)

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20 pages, 8350 KiB

Open AccessArticle

Intra-Minute Cloud Passing Forecasting Based on a Low Cost IoT Sensor—A Solution for Smoothing the Output Power of PV Power Plants

by Primož Sukič and Gorazd Štumberger^*

Faculty of Electrical Engineering and Computer Science, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia

Sensors 2017, 17(5), 1116; https://doi.org/10.3390/s17051116 - 13 May 2017

Cited by 10 | Viewed by 5782

Abstract

Clouds moving at a high speed in front of the Sun can cause step changes in the output power of photovoltaic (PV) power plants, which can lead to voltage fluctuations and stability problems in the connected electricity networks. These effects can be reduced [...] Read more.

Clouds moving at a high speed in front of the Sun can cause step changes in the output power of photovoltaic (PV) power plants, which can lead to voltage fluctuations and stability problems in the connected electricity networks. These effects can be reduced effectively by proper short-term cloud passing forecasting and suitable PV power plant output power control. This paper proposes a low-cost Internet of Things (IoT)-based solution for intra-minute cloud passing forecasting. The hardware consists of a Raspberry PI Model B 3 with a WiFi connection and an OmniVision OV5647 sensor with a mounted wide-angle lens, a circular polarizing (CPL) filter and a natural density (ND) filter. The completely new algorithm for cloud passing forecasting uses the green and blue colors in the photo to determine the position of the Sun, to recognize the clouds, and to predict their movement. The image processing is performed in several stages, considering selectively only a small part of the photo relevant to the movement of the clouds in the vicinity of the Sun in the next minute. The proposed algorithm is compact, fast and suitable for implementation on low cost processors with low computation power. The speed of the cloud parts closest to the Sun is used to predict when the clouds will cover the Sun. WiFi communication is used to transmit this data to the PV power plant control system in order to decrease the output power slowly and smoothly. Full article

(This article belongs to the Section Physical Sensors)

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21 pages, 6195 KiB

Open AccessArticle

Characterization of Fine Metal Particles Derived from Shredded WEEE Using a Hyperspectral Image System: Preliminary Results

by Gabriele Candiani^1,*

, Nicoletta Picone², Loredana Pompilio³

, Monica Pepe¹

and Marcello Colledani^2,4

¹ Institute for the Electromagnetic Sensing of Environment, National Research Council, 20133 Milano, Italy

² Institute of Industrial Technologies and Automation, National Research Council, 20133 Milano, Italy

³ Department of Psychological, Health and Earth Sciences, G. D’Annunzio University, 66031 Chieti, Italy

⁴ Department of Mechanical Engineering, Polytechnic of Milan, 20156 Milano, Italy

Sensors 2017, 17(5), 1117; https://doi.org/10.3390/s17051117 - 13 May 2017

Cited by 27 | Viewed by 5975

Abstract

Waste of electric and electronic equipment (WEEE) is the fastest-growing waste stream in Europe. The large amount of electric and electronic products introduced every year in the market makes WEEE disposal a relevant problem. On the other hand, the high abundance of key [...] Read more.

Waste of electric and electronic equipment (WEEE) is the fastest-growing waste stream in Europe. The large amount of electric and electronic products introduced every year in the market makes WEEE disposal a relevant problem. On the other hand, the high abundance of key metals included in WEEE has increased the industrial interest in WEEE recycling. However, the high variability of materials used to produce electric and electronic equipment makes key metals’ recovery a complex task: the separation process requires flexible systems, which are not currently implemented in recycling plants. In this context, hyperspectral sensors and imaging systems represent a suitable technology to improve WEEE recycling rates and the quality of the output products. This work introduces the preliminary tests using a hyperspectral system, integrated in an automatic WEEE recycling pilot plant, for the characterization of mixtures of fine particles derived from WEEE shredding. Several combinations of classification algorithms and techniques for signal enhancement of reflectance spectra were implemented and compared. The methodology introduced in this study has shown characterization accuracies greater than 95%. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technologies in Italy 2016)

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19 pages, 14112 KiB

Open AccessArticle

Comprehensive and Highly Accurate Measurements of Crane Runways, Profiles and Fastenings

by Dirk Dennig^1,*, Johannes Bureick¹, Johannes Link¹, Dmitri Diener¹, Christian Hesse² and Ingo Neumann¹

¹ Geodetic Institute, Leibniz Universität Hannover, Nienburger Str. 1, 30167 Hannover, Germany

² Dr. Hesse und Partner Ingenieure, Veritaskai 6, 21079 Hamburg, Germany

Sensors 2017, 17(5), 1118; https://doi.org/10.3390/s17051118 - 13 May 2017

Cited by 18 | Viewed by 10241

Abstract

The process of surveying crane runways has been continually refined due to the competitive situation, modern surveying instruments, additional sensors, accessories and evaluation procedures. Guidelines, such as the International Organization for Standardization (ISO) 12488-1, define target values that must be determined by survey. [...] Read more.

The process of surveying crane runways has been continually refined due to the competitive situation, modern surveying instruments, additional sensors, accessories and evaluation procedures. Guidelines, such as the International Organization for Standardization (ISO) 12488-1, define target values that must be determined by survey. For a crane runway these are for example the span, the position and height of the rails. The process has to be objective and reproducible. However, common processes of surveying crane runways do not meet these requirements sufficiently. The evaluation of the protocols, ideally by an expert, requires many years of experience. Additionally, the recording of crucial parameters, e.g., the wear of the rail, or the condition of the rail fastening and rail joints, is not regulated and for that reason are often not considered during the measurement. To solve this deficit the Advanced Rail Track Inspection System (ARTIS) was developed. ARTIS is used to measure the 3D position of crane rails, the cross-section of the crane rails, joints and, for the first time, the (crane-rail) fastenings. The system consists of a monitoring vehicle and an external tracking sensor. It makes kinematic observations with the tracking sensor from outside the rail run, e.g., the floor of an overhead crane runway, possible. In this paper we present stages of the development process of ARTIS, new target values, calibration of sensors and results of a test measurement. Full article

(This article belongs to the Special Issue Laser Sensors for Displacement, Distance, Flow, Velocity and Vibrations Measurements)

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13 pages, 3358 KiB

Open AccessArticle

Squeeze-Film Air Damping of a Five-Axis Electrostatic Bearing for Rotary Micromotors

by Shunyue Wang, Fengtian Han^*

, Boqian Sun and Haixia Li^*

Department of Precision Instrument, Tsinghua University, Beijing 100084, China

Sensors 2017, 17(5), 1119; https://doi.org/10.3390/s17051119 - 13 May 2017

Cited by 9 | Viewed by 5850

Abstract

Air-film damping, which dominates over other losses, plays a significant role in the dynamic response of many micro-fabricated devices with a movable mass suspended by various bearing mechanisms. Modeling the damping characteristics accurately will be greatly helpful to the bearing design, control, and [...] Read more.

Air-film damping, which dominates over other losses, plays a significant role in the dynamic response of many micro-fabricated devices with a movable mass suspended by various bearing mechanisms. Modeling the damping characteristics accurately will be greatly helpful to the bearing design, control, and test in various micromotor devices. This paper presents the simulated and experimental squeeze-film air damping results of an electrostatic bearing for use in a rotary high-speed micromotor. It is shown that the boundary condition to solve the three-dimensional Reynolds equation, which governs the squeeze-film damping in the air gap between the rotor and its surrounding stator sealed in a three-layer evacuated cavity, behaves with strong cross-axis coupling characteristics. To accurately characterize the damping effect, a set of multiphysics finite-element simulations are performed by computing both the rotor velocity and the distribution of the viscous damping force acting on the rotor. The damping characteristics varying with several key structure parameters are simulated and discussed to optimize the device structure for desirable rotor dynamics. An electrical measurement method is also proposed and applied to validate the numerical results of the damping coefficients experimentally. Given that the frequency response of the electric bearing is critically dependent on the damping coefficients at atmospheric pressure, a solution to the air-film damping measurement problem is presented by taking approximate curve fitting of multi-axis experimental frequency responses. The measured squeeze-film damping coefficients for the five-axis electric bearing agrees well with the numerical solutions. This indicates that numerical multiphysics simulation is an effective method to accurately examine the air-film damping effect for complex device geometry and arbitrary boundary condition. The accurate damping coefficients obtained by FEM simulation will greatly simplify the design of the five-axis bearing control system and facilitate the initial suspension test of the rotor for various micromotor devices. Full article

(This article belongs to the Section Physical Sensors)

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14 pages, 473 KiB

Open AccessArticle

Sparsity Adaptive Matching Pursuit Detection Algorithm Based on Compressed Sensing for Radar Signals

by Yanbo Wei¹, Zhizhong Lu^1,*

, Gannan Yuan¹, Zhao Fang¹ and Yu Huang²

¹ College of Automation, Harbin Engineering University, No. 145 Nantong Street, Harbin 150001, China

² College of Science, Harbin Engineering University, No. 145 Nantong Street, Harbin 150001, China

Sensors 2017, 17(5), 1120; https://doi.org/10.3390/s17051120 - 13 May 2017

Cited by 28 | Viewed by 5073

Abstract

In this paper, the application of the emerging compressed sensing (CS) theory and the geometric characteristics of the targets in radar images are investigated. Currently, the signal detection algorithms based on the CS theory require knowing the prior knowledge of the sparsity of [...] Read more.

In this paper, the application of the emerging compressed sensing (CS) theory and the geometric characteristics of the targets in radar images are investigated. Currently, the signal detection algorithms based on the CS theory require knowing the prior knowledge of the sparsity of target signals. However, in practice, it is often impossible to know the sparsity in advance. To solve this problem, a novel sparsity adaptive matching pursuit (SAMP) detection algorithm is proposed. This algorithm executes the detection task by updating the support set and gradually increasing the sparsity to approximate the original signal. To verify the effectiveness of the proposed algorithm, the data collected in 2010 at Pingtan, which located on the coast of the East China Sea, were applied. Experiment results illustrate that the proposed method adaptively completes the detection task without knowing the signal sparsity, and the similar detection performance is close to the matching pursuit (MP) and orthogonal matching pursuit (OMP) detection algorithms. Full article

(This article belongs to the Section Remote Sensors)

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9 pages, 1828 KiB

Open AccessArticle

Nonlinear Parameter Identification of a Resonant Electrostatic MEMS Actuator

by Majed S. Al-Ghamdi¹, Ayman M. Alneamy¹, Sangtak Park¹, Beichen Li², Mahmoud E. Khater³, Eihab M. Abdel-Rahman^1,*

, Glenn R. Heppler¹ and Mustafa Yavuz²

¹ Department of Systems Design Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada

² Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada

³ Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia

Sensors 2017, 17(5), 1121; https://doi.org/10.3390/s17051121 - 13 May 2017

Cited by 15 | Viewed by 5812

Abstract

We experimentally investigate the primary superharmonic of order two and subharmonic of order one-half resonances of an electrostatic MEMS actuator under direct excitation. We identify the parameters of a one degree of freedom (1-DOF) generalized Duffing oscillator model representing it. The experiments were [...] Read more.

We experimentally investigate the primary superharmonic of order two and subharmonic of order one-half resonances of an electrostatic MEMS actuator under direct excitation. We identify the parameters of a one degree of freedom (1-DOF) generalized Duffing oscillator model representing it. The experiments were conducted in soft vacuum to reduce squeeze-film damping, and the actuator response was measured optically using a laser vibrometer. The predictions of the identified model were found to be in close agreement with the experimental results. We also identified the noise spectral density of process (actuation voltage) and measurement noise. Full article

(This article belongs to the Special Issue MEMS and Nano-Sensors)

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17 pages, 30448 KiB

Open AccessArticle

Measurement of Vibrations in Two Tower-Typed Assistant Personal Robot Implementations with and without a Passive Suspension System

by Javier Moreno¹, Eduard Clotet¹, Marcel Tresanchez¹, Dani Martínez¹, Jordi Casanovas² and Jordi Palacín^1,*

¹ Department of Computer Science and Industrial Engineering, University of Lleida, 25001 Lleida, Spain

² Department of Chemistry, University of Lleida, 25001 Lleida, Spain

Sensors 2017, 17(5), 1122; https://doi.org/10.3390/s17051122 - 14 May 2017

Cited by 16 | Viewed by 5975

Abstract

This paper presents the vibration pattern measurement of two tower-typed holonomic mobile robot prototypes: one based on a rigid mechanical structure, and the other including a passive suspension system. Specific to the tower-typed mobile robots is that the vibrations that originate in the [...] Read more.

This paper presents the vibration pattern measurement of two tower-typed holonomic mobile robot prototypes: one based on a rigid mechanical structure, and the other including a passive suspension system. Specific to the tower-typed mobile robots is that the vibrations that originate in the lower part of the structure are transmitted and amplified to the higher areas of the tower, causing an unpleasant visual effect and mechanical stress. This paper assesses the use of a suspension system aimed at minimizing the generation and propagation of vibrations in the upper part of the tower-typed holonomic robots. The two robots analyzed were equipped with onboard accelerometers to register the acceleration over the X, Y, and Z axes in different locations and at different velocities. In all the experiments, the amplitude of the vibrations showed a typical Gaussian pattern which has been modeled with the value of the standard deviation. The results have shown that the measured vibrations in the head of the mobile robots, including a passive suspension system, were reduced by a factor of 16. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Spain 2017)

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17 pages, 3890 KiB

Open AccessArticle

Sea Ice Detection Based on an Improved Similarity Measurement Method Using Hyperspectral Data

by Yanling Han, Jue Li, Yun Zhang^*, Zhonghua Hong

and Jing Wang

College of Information Technology, Shanghai Ocean University; Shanghai 201306, China

Sensors 2017, 17(5), 1124; https://doi.org/10.3390/s17051124 - 15 May 2017

Cited by 27 | Viewed by 5315

Abstract

Hyperspectral remote sensing technology can acquire nearly continuous spectrum information and rich sea ice image information, thus providing an important means of sea ice detection. However, the correlation and redundancy among hyperspectral bands reduce the accuracy of traditional sea ice detection methods. Based [...] Read more.

Hyperspectral remote sensing technology can acquire nearly continuous spectrum information and rich sea ice image information, thus providing an important means of sea ice detection. However, the correlation and redundancy among hyperspectral bands reduce the accuracy of traditional sea ice detection methods. Based on the spectral characteristics of sea ice, this study presents an improved similarity measurement method based on linear prediction (ISMLP) to detect sea ice. First, the first original band with a large amount of information is determined based on mutual information theory. Subsequently, a second original band with the least similarity is chosen by the spectral correlation measuring method. Finally, subsequent bands are selected through the linear prediction method, and a support vector machine classifier model is applied to classify sea ice. In experiments performed on images of Baffin Bay and Bohai Bay, comparative analyses were conducted to compare the proposed method and traditional sea ice detection methods. Our proposed ISMLP method achieved the highest classification accuracies (91.18% and 94.22%) in both experiments. From these results the ISMLP method exhibits better performance overall than other methods and can be effectively applied to hyperspectral sea ice detection. Full article

(This article belongs to the Special Issue Marine Sensing)

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9 pages, 2637 KiB

Open AccessArticle

Dynamic and Steady Characteristics of Polymer-Ceramic Pressure-Sensitive Paint with Variation in Layer Thickness

by Tatsunori Hayashi and Hirotaka Sakaue^*

Hessert Laboratory for Aerospace Research, Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA

Sensors 2017, 17(5), 1125; https://doi.org/10.3390/s17051125 - 15 May 2017

Cited by 34 | Viewed by 5198

Abstract

Polymer-ceramic pressure-sensitive paint (PC-PSP) has been investigated as a surface-pressure sensor for unsteady aerodynamics and short duration measurements. This PSP provides a fast response to a change in pressures with a spray-coating ability. Because it is sprayed onto an aerodynamic surface, the thickness [...] Read more.

Polymer-ceramic pressure-sensitive paint (PC-PSP) has been investigated as a surface-pressure sensor for unsteady aerodynamics and short duration measurements. This PSP provides a fast response to a change in pressures with a spray-coating ability. Because it is sprayed onto an aerodynamic surface, the thickness of PC-PSP may play an important role in determining the performance of this sensor. The thickness of other fast PSPs, such as anodized aluminum pressure-sensitive paint, is a major factor in determining its performance. We vary the thickness of PC-PSP from 10 to 240 μm in order to study its effects on PSP measurement characteristics including time response, signal level, pressure sensitivity, and temperature dependency. It is found that the thickness does affect these characteristics. However, a thickness over 80 μm provides uniform performance in these characteristics. Full article

(This article belongs to the Section Physical Sensors)

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11 pages, 1238 KiB

Open AccessArticle

Reduction of the Influence of Laser Beam Directional Dithering in a Laser Triangulation Displacement Probe

by Hongwei Yang, Wei Tao^*, Zhengqi Zhang, Siwei Zhao, Xiaoqia Yin and Hui Zhao

Department of Instrument and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

Sensors 2017, 17(5), 1126; https://doi.org/10.3390/s17051126 - 15 May 2017

Cited by 35 | Viewed by 8907

Abstract

Directional dithering of a laser beam potentially limits the detection accuracy of a laser triangulation displacement probe. A theoretical analysis indicates that the measurement accuracy will linearly decrease as the laser dithering angle increases. To suppress laser dithering, a scheme for reduction of [...] Read more.

Directional dithering of a laser beam potentially limits the detection accuracy of a laser triangulation displacement probe. A theoretical analysis indicates that the measurement accuracy will linearly decrease as the laser dithering angle increases. To suppress laser dithering, a scheme for reduction of the influence of laser beam directional dithering in a laser triangulation displacement probe, which consists of a collimated red laser, a laser beam pointing control setup, a receiver lens, and a charge-coupled device, is proposed in this paper. The laser beam pointing control setup is inserted into the source laser beam and the measured object and can separate the source laser beam into two symmetrical laser beams. Hence, at the angle at which the source laser beam dithers, the positional averages of the two laser spots are equal and opposite. Moreover, a virtual linear function method is used to maintain a stable average of the positions of the two spots on the imaging side. Experimental results indicate that with laser beam pointing control, the estimated standard deviation of the fitting error decreases from 0.3531

mm

to 0.0100

mm

, the repeatability accuracy can be lowered from ±7

mm

to ±5

μ m

, and the nonlinear error can be reduced from ±6 % FS (full scale) to ±0.16 % FS. Full article

(This article belongs to the Special Issue Laser Sensors for Displacement, Distance, Flow, Velocity and Vibrations Measurements)

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15 pages, 4215 KiB

Open AccessArticle

Airborne Infrared and Visible Image Fusion Combined with Region Segmentation

by Yujia Zuo^1,2, Jinghong Liu^1,*, Guanbing Bai^1,2, Xuan Wang^1,2 and Mingchao Sun¹

¹ Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Science, #3888 Dongnanhu Road, Changchun 130033, China

² University of Chinese Academy of Sciences, #19 Yuquan Road, Beijing 100049, China

Sensors 2017, 17(5), 1127; https://doi.org/10.3390/s17051127 - 15 May 2017

Cited by 34 | Viewed by 6100

Abstract

This paper proposes an infrared (IR) and visible image fusion method introducing region segmentation into the dual-tree complex wavelet transform (DTCWT) region. This method should effectively improve both the target indication and scene spectrum features of fusion images, and the target identification and [...] Read more.

This paper proposes an infrared (IR) and visible image fusion method introducing region segmentation into the dual-tree complex wavelet transform (DTCWT) region. This method should effectively improve both the target indication and scene spectrum features of fusion images, and the target identification and tracking reliability of fusion system, on an airborne photoelectric platform. The method involves segmenting the region in an IR image by significance, and identifying the target region and the background region; then, fusing the low-frequency components in the DTCWT region according to the region segmentation result. For high-frequency components, the region weights need to be assigned by the information richness of region details to conduct fusion based on both weights and adaptive phases, and then introducing a shrinkage function to suppress noise; Finally, the fused low-frequency and high-frequency components are reconstructed to obtain the fusion image. The experimental results show that the proposed method can fully extract complementary information from the source images to obtain a fusion image with good target indication and rich information on scene details. They also give a fusion result superior to existing popular fusion methods, based on eithers subjective or objective evaluation. With good stability and high fusion accuracy, this method can meet the fusion requirements of IR-visible image fusion systems. Full article

(This article belongs to the Special Issue Multi-Sensor Integration and Fusion)

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12 pages, 290 KiB

Open AccessArticle

Simultaneous Wireless Power Transfer and Secure Multicasting in Cooperative Decode-and-Forward Relay Networks

by Jong-Ho Lee¹

, Illsoo Sohn² and Yong-Hwa Kim^3,*

¹ Department of Electronic Engineering, Gachon University, Seongnam, Gyeonggi 13120, Korea

² Department of Computer Science and Engineering, Seoul National University of Science and Technology, Seoul 01811, Korea

³ Department of Electronic Engineering, Myongji University, Yongin, Gyeonggi 17058, Korea

Sensors 2017, 17(5), 1128; https://doi.org/10.3390/s17051128 - 16 May 2017

Cited by 3 | Viewed by 4830

Abstract

In this paper, we investigate simultaneous wireless power transfer and secure multicasting via cooperative decode-and-forward (DF) relays in the presence of multiple energy receivers and eavesdroppers. Two scenarios are considered under a total power budget: maximizing the minimum harvested energy among the energy [...] Read more.

In this paper, we investigate simultaneous wireless power transfer and secure multicasting via cooperative decode-and-forward (DF) relays in the presence of multiple energy receivers and eavesdroppers. Two scenarios are considered under a total power budget: maximizing the minimum harvested energy among the energy receivers under a multicast secrecy rate constraint; and maximizing the multicast secrecy rate under a minimum harvested energy constraint. For both scenarios, we solve the transmit power allocation and relay beamformer design problems by using semidefinite relaxation and bisection technique. We present numerical results to analyze the energy harvesting and secure multicasting performances in cooperative DF relay networks. Full article

(This article belongs to the Special Issue Wireless Rechargeable Sensor Networks)

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17 pages, 3623 KiB

Open AccessArticle

A Robust Method to Detect BeiDou Navigation Satellite System Orbit Maneuvering/Anomalies and Its Applications to Precise Orbit Determination

by Fei Ye^1,2,*

, Yunbin Yuan¹, Bingfeng Tan¹

and Jikun Ou¹

¹ State Key Laboratory of Geodesy and Earth’s Dynamics, Institute of Geodesy and Geophysics, 340 Xudong Rd., Wuhan 430077, China

² University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China

Sensors 2017, 17(5), 1129; https://doi.org/10.3390/s17051129 - 16 May 2017

Cited by 27 | Viewed by 4496

Abstract

The failure to detect anomalies and maneuvering of the orbits of navigation satellite sensors will deteriorate the performance of positioning and orbit determination. Motivated by the influence of the frequent maneuvering of BDS GEO and IGSO satellites, this paper analyzes the limitations of [...] Read more.

The failure to detect anomalies and maneuvering of the orbits of navigation satellite sensors will deteriorate the performance of positioning and orbit determination. Motivated by the influence of the frequent maneuvering of BDS GEO and IGSO satellites, this paper analyzes the limitations of existing methods, where BDS orbit maneuvering and anomalies can be detected, and develops a method to solve this problem based on the RMS model of orbit mutual differences proposed in this paper. The performance of this method was assessed by comparison with the health flag of broadcast ephemeris, precise orbit products of GFZ, the O-C values of a GNSS station and a conventional method. The results show that the performance of the method developed in this paper is better than that of the conventional method when the periodicity and trend items are obvious. Meanwhile, three additional verification results show that the method developed in this paper can find error information in the merged broadcast ephemeris provided by iGMAS. Furthermore, from the testing results, it can be seen that the detection of anomaly and maneuvering items do not affect each other based on the robust thresholds constructed in this paper. In addition, the precise orbit of the maneuvering satellites can be determined under the circumstances that the maneuver information detected in this paper is used, and the root mean square (RMS) of orbit overlap comparison for GEO-03/IGSO-03 in Radial, Along, Cross, 1D-RMS are 0.7614/0.4460 m, 1.8901/0.3687 m, 0.3392/0.2069 m, 2.0657/0.6145 m, respectively. Full article

(This article belongs to the Section Remote Sensors)

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14 pages, 4368 KiB

Open AccessArticle

A Fairness Oriented Neighbor-Channel-Aware MAC Protocol for Airborne Sensor Networks

by Xiaolin Gao^1,2, Jian Yan^3,* and Jianhua Lu¹

¹ Department of Electronic Engineering, Tsinghua University, Beijing 100084, China

² Beijing Aerospace Control Center, Beijing 100094, China

³ Tsinghua Space Center, Tsinghua University, Beijing 100084, China

Sensors 2017, 17(5), 1130; https://doi.org/10.3390/s17051130 - 16 May 2017

Cited by 1 | Viewed by 3569

Abstract

In airborne sensor networks (ASNs), the media access control (MAC) protocol faces a serious unfairness problem due to the traditional protection mechanism of air-to-air communications among aircraft. Actually, by using the binary exponential back-off algorithm at high traffic loads to minimize collisions among [...] Read more.

In airborne sensor networks (ASNs), the media access control (MAC) protocol faces a serious unfairness problem due to the traditional protection mechanism of air-to-air communications among aircraft. Actually, by using the binary exponential back-off algorithm at high traffic loads to minimize collisions among users, the latest successful node can always benefit from this kind of MAC to obtain channel resources. Moreover, when taking the existence of the hidden nodes in ASNs into account, the inaccurate traffic load information will further aggravate the system’s unfairness. In this paper, a neighbor-channel-aware (NCA) protocol is proposed to improve the fairness of MAC protocol in ASNs. In the proposal, the NCA frame is firstly added and exchanged between neighbor nodes periodically, which helps to resolve the inaccurate traffic load information, so as to avoid reducing the probability of successful message transmission. Then a traffic-loading based back-off algorithm is involved to make the neighbor nodes cooperatively adjust the inter-frame space (IFS) interval to further reduce the unfairness. The simulation results show that, the proposed MAC protocol can guarantee the satisfied fairness, simultaneously avoiding heavy network overloads to protect key messages’ successful transmissions in ASNs. Full article

(This article belongs to the Section Sensor Networks)

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15 pages, 1757 KiB

Open AccessArticle

Modeling the Footprint and Equivalent Radiance Transfer Path Length for Tower-Based Hemispherical Observations of Chlorophyll Fluorescence

by Xinjie Liu¹

, Liangyun Liu^1,*

, Jiaochan Hu^1,2 and Shanshan Du^1,2

¹ Key Laboratory of Digital Earth Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100094, China

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

Sensors 2017, 17(5), 1131; https://doi.org/10.3390/s17051131 - 16 May 2017

Cited by 30 | Viewed by 5826

Abstract

The measurement of solar-induced chlorophyll fluorescence (SIF) is a new tool for estimating gross primary production (GPP). Continuous tower-based spectral observations together with flux measurements are an efficient way of linking the SIF to the GPP. Compared to conical observations, hemispherical observations made [...] Read more.

The measurement of solar-induced chlorophyll fluorescence (SIF) is a new tool for estimating gross primary production (GPP). Continuous tower-based spectral observations together with flux measurements are an efficient way of linking the SIF to the GPP. Compared to conical observations, hemispherical observations made with cosine-corrected foreoptic have a much larger field of view and can better match the footprint of the tower-based flux measurements. However, estimating the equivalent radiation transfer path length (ERTPL) for hemispherical observations is more complex than for conical observations and this is a key problem that needs to be addressed before accurate retrieval of SIF can be made. In this paper, we first modeled the footprint of hemispherical spectral measurements and found that, under convective conditions with light winds, 90% of the total radiation came from an FOV of width 72°, which in turn covered 75.68% of the source area of the flux measurements. In contrast, conical spectral observations covered only 1.93% of the flux footprint. Secondly, using theoretical considerations, we modeled the ERTPL of the hemispherical spectral observations made with cosine-corrected foreoptic and found that the ERTPL was approximately equal to twice the sensor height above the canopy. Finally, the modeled ERTPL was evaluated using a simulated dataset. The ERTPL calculated using the simulated data was about 1.89 times the sensor’s height above the target surface, which was quite close to the results for the modeled ERTPL. Furthermore, the SIF retrieved from atmospherically corrected spectra using the modeled ERTPL fitted well with the reference values, giving a relative root mean square error of 18.22%. These results show that the modeled ERTPL was reasonable and that this method is applicable to tower-based hemispherical observations of SIF. Full article

(This article belongs to the Special Issue Earth Observation for Biodiversity and Ecosystem Services: Remote Sensing Data Handling and Analysis)

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14 pages, 3524 KiB

Open AccessArticle

Biosensor Based on Tyrosinase Immobilized on Graphene-Decorated Gold Nanoparticle/Chitosan for Phenolic Detection in Aqueous

by Fuzi Mohamed Fartas¹, Jaafar Abdullah^1,2,*

, Nor Azah Yusof^1,2, Yusran Sulaiman^1,2

and Mohd Izham Saiman¹

¹ Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor D.E., Malaysia

² Institute of Advanced Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor D.E., Malaysia

Sensors 2017, 17(5), 1132; https://doi.org/10.3390/s17051132 - 16 May 2017

Cited by 70 | Viewed by 7545

Abstract

In this research work, electrochemical biosensor was fabricated based on immobilization of tyrosinase onto graphene-decorated gold nanoparticle/chitosan (Gr-Au-Chit/Tyr) nanocomposite-modified screen-printed carbon electrode (SPCE) for the detection of phenolic compounds. The nanocomposite film was constructed via solution casting method. The electrocatalytic activity of the [...] Read more.

In this research work, electrochemical biosensor was fabricated based on immobilization of tyrosinase onto graphene-decorated gold nanoparticle/chitosan (Gr-Au-Chit/Tyr) nanocomposite-modified screen-printed carbon electrode (SPCE) for the detection of phenolic compounds. The nanocomposite film was constructed via solution casting method. The electrocatalytic activity of the proposed biosensor for phenol detection was studied using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Experimental parameters such as pH buffer, enzyme concentration, ratio of Gr-Au-Chit, accumulation time and potential were optimized. The biosensor shows linearity towards phenol in the concentration range from 0.05 to 15 μM with sensitivity of 0.624 μA/μM and the limit of detection (LOD) of 0.016 μM (S/N = 3). The proposed sensor also depicts good reproducibility, selectivity and stability for at least one month. The biosensor was compared with high-performance liquid chromatography (HPLC) method for the detection of phenol spiked in real water samples and the result is in good agreement and comparable. Full article

(This article belongs to the Section Biosensors)

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16 pages, 1023 KiB

Open AccessArticle

A Probabilistically Weakly Secure Network Coding Scheme in Multipath Routing for WSNs

by Xiang Liu^*

, Jie Huang and Xiang Gao

School of Information Science and Engineering, Southeast University, Nanjing 210096, China

Sensors 2017, 17(5), 1133; https://doi.org/10.3390/s17051133 - 16 May 2017

Cited by 2 | Viewed by 3873

Abstract

In wireless sensor networks, nodes are mostly deployed in unsupervised areas and are vulnerable to a variety of attacks. Therefore, data security is a vital aspect to be considered. However, due to the limited computation capability and memory of sensor nodes, it is [...] Read more.

In wireless sensor networks, nodes are mostly deployed in unsupervised areas and are vulnerable to a variety of attacks. Therefore, data security is a vital aspect to be considered. However, due to the limited computation capability and memory of sensor nodes, it is difficult to perform the complex encryption algorithm, as well as the key distribution and management algorithm. Toward this end, a low-complexity algorithm for security in wireless sensor networks is of significant importance. In this article, a weakly secure network coding based multipath routing scheme is proposed, which can guarantee the data confidentiality in transmission probabilistically, and can improve the energy efficiency in the meantime. Then the simulations of the probability of transmission being secure are performed. The results show that with the increase of the number of hops k, the probability of transmission being secure suffers from a rapid decrease. On the contrary, with the increase of multicast capacity h it undergoes a slight growth. Therefore, the weak security can be achieved with probability approaching 1 by limiting the number of hops and increasing the multicast capacity. Meanwhile, the simulations of energy consumption are performed and the comparison between the energy consumption of the scheme in this article and the multipath routing scheme without network coding is conducted. The results show that by employing network coding, the scheme in this article can improve the energy efficiency, and the more packets transmitted, the more energy consumption can be reduced. Full article

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26 pages, 1910 KiB

Open AccessArticle

Low Duty-Cycling MAC Protocol for Low Data-Rate Medical Wireless Body Area Networks

by Chongqing Zhang^1,2, Yinglong Wang², Yongquan Liang¹, Minglei Shu², Jinquan Zhang¹ and Lina Ni^1,3,*

¹ College of Computer Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, China

² Shandong Provincial Key Laboratory of Computer Networks, Shandong Computer Science Center, National Supercomputer Center in Jinan, Jinan 250101, China

³ The Key Laboratory of Embedded System and Service Computing, Ministry of Education, Tongji University, Shanghai 200092, China

Sensors 2017, 17(5), 1134; https://doi.org/10.3390/s17051134 - 16 May 2017

Cited by 10 | Viewed by 4852

Abstract

Wireless body area networks (WBANs) are severely energy constrained, and how to improve the energy efficiency so as to prolong the network lifetime as long as possible is one of the most important goals of WBAN research. Low data-rate WBANs are promising to [...] Read more.

Wireless body area networks (WBANs) are severely energy constrained, and how to improve the energy efficiency so as to prolong the network lifetime as long as possible is one of the most important goals of WBAN research. Low data-rate WBANs are promising to cut down the energy consumption and extend the network lifetime. Considering the characteristics and demands of low data-rate WBANs, a low duty-cycling medium access control (MAC) protocol is specially designed for this kind of WBAN in this paper. Longer superframes are exploited to cut down the energy consumed on the transmissions and receptions of redundant beacon frames. Insertion time slots are embedded into the inactive part of a superframe to deliver the frames and satisfy the quality of service (QoS) requirements. The number of the data subsections in an insertion time slot can be adaptively adjusted so as to accommodate low data-rate WBANs with different traffic. Simulation results show that the proposed MAC protocol performs well under the condition of low data-rate monitoring traffic. Full article

(This article belongs to the Special Issue New Advances in Identification, Information & Knowledge in the Internet of Things)

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20 pages, 2413 KiB

Open AccessArticle

A Combined Independent Source Separation and Quality Index Optimization Method for Fetal ECG Extraction from Abdominal Maternal Leads

by Lucia Billeci^*

and Maurizio Varanini

Institute of Clinical Physiology, National Research Council of Italy, via Moruzzi 1, 56124 Pisa, Italy

Sensors 2017, 17(5), 1135; https://doi.org/10.3390/s17051135 - 16 May 2017

Cited by 27 | Viewed by 5830

Abstract

The non-invasive fetal electrocardiogram (fECG) technique has recently received considerable interest in monitoring fetal health. The aim of our paper is to propose a novel fECG algorithm based on the combination of the criteria of independent source separation and of a quality index [...] Read more.

The non-invasive fetal electrocardiogram (fECG) technique has recently received considerable interest in monitoring fetal health. The aim of our paper is to propose a novel fECG algorithm based on the combination of the criteria of independent source separation and of a quality index optimization (ICAQIO-based). The algorithm was compared with two methods applying the two different criteria independently—the ICA-based and the QIO-based methods—which were previously developed by our group. All three methods were tested on the recently implemented Fetal ECG Synthetic Database (FECGSYNDB). Moreover, the performance of the algorithm was tested on real data from the PhysioNet fetal ECG Challenge 2013 Database. The proposed combined method outperformed the other two algorithms on the FECGSYNDB (ICAQIO-based: 98.78%, QIO-based: 97.77%, ICA-based: 97.61%). Significant differences were obtained in particular in the conditions when uterine contractions and maternal and fetal ectopic beats occurred. On the real data, all three methods obtained very high performances, with the QIO-based method proving slightly better than the other two (ICAQIO-based: 99.38%, QIO-based: 99.76%, ICA-based: 99.37%). The findings from this study suggest that the proposed method could potentially be applied as a novel algorithm for accurate extraction of fECG, especially in critical recording conditions. Full article

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

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9 pages, 2317 KiB

Open AccessArticle

Development of a Flow Injection Based High Frequency Dual Channel Quartz Crystal Microbalance

by Jinxing Liang^1,*, Jing Zhang¹, Wenxiang Zhou¹ and Toshitsugu Ueda²

¹ Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology, Ministry of Education, School of Instrument Science and Engineering, Southeast University, Nanjing 210096, China

² Research Center of the Graduate school of IPS, Waseda University, Kitakyushu 808-0135, Japan

Sensors 2017, 17(5), 1136; https://doi.org/10.3390/s17051136 - 16 May 2017

Cited by 5 | Viewed by 6007

Abstract

When the quartz crystal microbalance (QCM) is used in liquid for adsorption or desorption monitoring based bio- or chemical sensing applications, the frequency shift is not only determined by the surface mass change, but also by the change of liquid characteristics, such as [...] Read more.

When the quartz crystal microbalance (QCM) is used in liquid for adsorption or desorption monitoring based bio- or chemical sensing applications, the frequency shift is not only determined by the surface mass change, but also by the change of liquid characteristics, such as density and viscosity, which are greatly affected by the liquid environmental temperature. A monolithic dual-channel QCM is designed and fabricated by arranging two QCM resonators on one single chip for cancelling the fluctuation induced by environmental factors. In actual applications, one QCM works as a specific sensor by modifying with functional membranes and the other acts as a reference, only measuring the liquid property. The dual-channel QCM is designed with an inverted-mesa structure, aiming to realize a high frequency miniaturized chip and suppress the frequency interference between the neighbored QCM resonators. The key problem of dual-channel QCMs is the interference between two channels, which is influenced by the distance of adjacent resonators. The diameter of the reference electrode has been designed into several values in order to find the optimal parameter. Experimental results demonstrated that the two QCMs could vibrate individually and the output frequency stability and drift can be greatly improved with the aid of the reference QCM. Full article

(This article belongs to the Special Issue Intelligent Sensing and Information Mining—Selected Papers from the 10th International Conference on Sensing Technology)

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21 pages, 3292 KiB

Open AccessArticle

Experimental Approach for the Uncertainty Assessment of 3D Complex Geometry Dimensional Measurements Using Computed Tomography at the mm and Sub-mm Scales

by Roberto Jiménez¹

, Marta Torralba^1,*, José A. Yagüe-Fabra²

, Sinué Ontiveros³ and Guido Tosello⁴

¹ Centro Universitario de la Defensa, A.G.M. Carretera Huesca s/n, 50090 Zaragoza, Spain

² I3A, Universidad de Zaragoza, María de Luna 3, 50018 Zaragoza, Spain

³ Department of Industrial Engineering, Autonomous University of Baja California, 14418 Tijuana, Mexico

⁴ Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark

Sensors 2017, 17(5), 1137; https://doi.org/10.3390/s17051137 - 16 May 2017

Cited by 15 | Viewed by 4198

Abstract

The dimensional verification of miniaturized components with 3D complex geometries is particularly challenging. Computed Tomography (CT) can represent a suitable alternative solution to micro metrology tools based on optical and tactile techniques. However, the establishment of CT systems’ traceability when measuring 3D complex [...] Read more.

The dimensional verification of miniaturized components with 3D complex geometries is particularly challenging. Computed Tomography (CT) can represent a suitable alternative solution to micro metrology tools based on optical and tactile techniques. However, the establishment of CT systems’ traceability when measuring 3D complex geometries is still an open issue. In this work, an alternative method for the measurement uncertainty assessment of 3D complex geometries by using CT is presented. The method is based on the micro-CT system Maximum Permissible Error (MPE) estimation, determined experimentally by using several calibrated reference artefacts. The main advantage of the presented method is that a previous calibration of the component by a more accurate Coordinate Measuring System (CMS) is not needed. In fact, such CMS would still hold all the typical limitations of optical and tactile techniques, particularly when measuring miniaturized components with complex 3D geometries and their inability to measure inner parts. To validate the presented method, the most accepted standard currently available for CT sensors, the Verein Deutscher Ingenieure/Verband Deutscher Elektrotechniker (VDI/VDE) guideline 2630-2.1 is applied. Considering the high number of influence factors in CT and their impact on the measuring result, two different techniques for surface extraction are also considered to obtain a realistic determination of the influence of data processing on uncertainty. The uncertainty assessment of a workpiece used for micro mechanical material testing is firstly used to confirm the method, due to its feasible calibration by an optical CMS. Secondly, the measurement of a miniaturized dental file with 3D complex geometry is carried out. The estimated uncertainties are eventually compared with the component’s calibration and the micro manufacturing tolerances to demonstrate the suitability of the presented CT calibration procedure. The 2U/T ratios resulting from the validation workpiece are, respectively, 0.27 (VDI) and 0.35 (MPE), by assuring tolerances in the range of ± 20–30 µm. For the dental file, the E_N < 1 value analysis is favorable in the majority of the cases (70.4%) and 2U/T is equal to 0.31 for sub-mm measurands (L < 1 mm and tolerance intervals of ± 40–80 µm). Full article

(This article belongs to the Section Physical Sensors)

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19 pages, 15346 KiB

Open AccessArticle

Detecting and Classifying Human Touches in a Social Robot Through Acoustic Sensing and Machine Learning

by Fernando Alonso-Martín^*, Juan José Gamboa-Montero

, José Carlos Castillo

, Álvaro Castro-González

and Miguel Ángel Salichs

Robotics Laboratory, Universidad Carlos III de Madrid, Av. de la Universidad 30, Leganés, 28911 Madrid, Spain

Sensors 2017, 17(5), 1138; https://doi.org/10.3390/s17051138 - 16 May 2017

Cited by 30 | Viewed by 7012

Abstract

An important aspect in Human–Robot Interaction is responding to different kinds of touch stimuli. To date, several technologies have been explored to determine how a touch is perceived by a social robot, usually placing a large number of sensors throughout the robot’s shell. [...] Read more.

An important aspect in Human–Robot Interaction is responding to different kinds of touch stimuli. To date, several technologies have been explored to determine how a touch is perceived by a social robot, usually placing a large number of sensors throughout the robot’s shell. In this work, we introduce a novel approach, where the audio acquired from contact microphones located in the robot’s shell is processed using machine learning techniques to distinguish between different types of touches. The system is able to determine when the robot is touched (touch detection), and to ascertain the kind of touch performed among a set of possibilities: stroke, tap, slap, and tickle (touch classification). This proposal is cost-effective since just a few microphones are able to cover the whole robot’s shell since a single microphone is enough to cover each solid part of the robot. Besides, it is easy to install and configure as it just requires a contact surface to attach the microphone to the robot’s shell and plug it into the robot’s computer. Results show the high accuracy scores in touch gesture recognition. The testing phase revealed that Logistic Model Trees achieved the best performance, with an F-score of 0.81. The dataset was built with information from 25 participants performing a total of 1981 touch gestures. Full article

(This article belongs to the Special Issue Acoustic Sensing and Ultrasonic Drug Delivery)

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12 pages, 1491 KiB

Open AccessArticle

Compact Eucapnic Voluntary Hyperpnoea Apparatus for Exercise-Induced Respiratory Disease Detection

by Lulu Wang^1,*

and Ahmed Al-Jumaily²

¹ School of Instrument Science and Opto-Electronics Engineering, Hefei University of Technology, Hefei 230009, China

² Institute of Biomedical Technologies, Auckland University of Technology, Auckland 1142, New Zealand

Sensors 2017, 17(5), 1139; https://doi.org/10.3390/s17051139 - 16 May 2017

Cited by 2 | Viewed by 4842

Abstract

Eucapnic voluntary hyperpnoea (EVH) challenge provides objective criteria for exercise-induced asthma (EIA) or exercise-induced bronchoconstriction (EIB), and it was recommended to justify the use of inhaled β₂-agonists by athletes for the Olympics. This paper presents the development of a compact and [...] Read more.

Eucapnic voluntary hyperpnoea (EVH) challenge provides objective criteria for exercise-induced asthma (EIA) or exercise-induced bronchoconstriction (EIB), and it was recommended to justify the use of inhaled β₂-agonists by athletes for the Olympics. This paper presents the development of a compact and easy-to-use EVH apparatus for assessing EIB in human subjects. The compact apparatus has been validated on human subjects and the results have been compared to the conventional EVH system. Twenty-two swimmers, including eleven healthy subjects and eleven subjects who had been physician-diagnosed with asthma, were recruited from sport and recreation centers throughout Auckland, New Zealand. Each subject performed two EVH challenge tests using the proposed breathing apparatus and the conventional Phillips EVH apparatus on separate days, respectively. Forced expiratory volume in one second (FEV₁) was measured before and after the challenges. A reduction in FEV₁ of 10% or more was considered positive. Of the eleven subjects who were previously diagnosed with asthma, EIB was present in all subjects (100%) in the compact EVH group, while it was presented in ten subjects (90.91%) in the conventional EVH challenge group. Of the eleven healthy subjects, EIB was present in one subject (4.55%) in the compact EVH group, while it was not present in the conventional EVH group. Experimental results showed that the compact EVH system has potential to become an alternative tool for EIB detection. Full article

(This article belongs to the Special Issue Force and Pressure Based Sensing Medical Application)

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12 pages, 341 KiB

Open AccessArticle

An Improved DOA Estimation Approach Using Coarray Interpolation and Matrix Denoising

by Muran Guo^1,3, Tao Chen^1,* and Ben Wang^2,3

¹ College of Information and Communication Engineering, Harbin Engineering University, No. 145 Nantong Street, Harbin 150001, China

² College of Automation, Harbin Engineering University, No. 145 Nantong Street, Harbin 150001, China

³ Depaprtment of Electrical and Computer Engineering, Temple University, Philadelphia, PA 19122, USA

Sensors 2017, 17(5), 1140; https://doi.org/10.3390/s17051140 - 16 May 2017

Cited by 37 | Viewed by 5507

Abstract

Co-prime arrays can estimate the directions of arrival (DOAs) of

O (M N)

sources with

O (M + N)

sensors, and are convenient to analyze due to their closed-form expression for the locations of virtual lags. However, the number [...] Read more.

Co-prime arrays can estimate the directions of arrival (DOAs) of

O (M N)

sources with

O (M + N)

sensors, and are convenient to analyze due to their closed-form expression for the locations of virtual lags. However, the number of degrees of freedom is limited due to the existence of holes in difference coarrays if subspace-based algorithms such as the spatial smoothing multiple signal classification (MUSIC) algorithm are utilized. To address this issue, techniques such as positive definite Toeplitz completion and array interpolation have been proposed in the literature. Another factor that compromises the accuracy of DOA estimation is the limitation of the number of snapshots. Coarray-based processing is particularly sensitive to the discrepancy between the sample covariance matrix and the ideal covariance matrix due to the finite number of snapshots. In this paper, coarray interpolation based on matrix completion (MC) followed by a denoising operation is proposed to detect more sources with a higher accuracy. The effectiveness of the proposed method is based on the capability of MC to fill in holes in the virtual sensors and that of MC denoising operation to reduce the perturbation in the sample covariance matrix. The results of numerical simulations verify the superiority of the proposed approach. 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, 5399 KiB

Open AccessArticle

A Study on Immersion and Presence of a Portable Hand Haptic System for Immersive Virtual Reality

by Mingyu Kim, Changyu Jeon and Jinmo Kim^*

Department of Software, Catholic University of Pusan, Busan 46252, Korea

Sensors 2017, 17(5), 1141; https://doi.org/10.3390/s17051141 - 17 May 2017

Cited by 112 | Viewed by 14843

Abstract

This paper proposes a portable hand haptic system using Leap Motion as a haptic interface that can be used in various virtual reality (VR) applications. The proposed hand haptic system was designed as an Arduino-based sensor architecture to enable a variety of tactile [...] Read more.

This paper proposes a portable hand haptic system using Leap Motion as a haptic interface that can be used in various virtual reality (VR) applications. The proposed hand haptic system was designed as an Arduino-based sensor architecture to enable a variety of tactile senses at low cost, and is also equipped with a portable wristband. As a haptic system designed for tactile feedback, the proposed system first identifies the left and right hands and then sends tactile senses (vibration and heat) to each fingertip (thumb and index finger). It is incorporated into a wearable band-type system, making its use easy and convenient. Next, hand motion is accurately captured using the sensor of the hand tracking system and is used for virtual object control, thus achieving interaction that enhances immersion. A VR application was designed with the purpose of testing the immersion and presence aspects of the proposed system. Lastly, technical and statistical tests were carried out to assess whether the proposed haptic system can provide a new immersive presence to users. According to the results of the presence questionnaire and the simulator sickness questionnaire, we confirmed that the proposed hand haptic system, in comparison to the existing interaction that uses only the hand tracking system, provided greater presence and a more immersive environment in the virtual reality. Full article

(This article belongs to the Section Physical Sensors)

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10 pages, 5478 KiB

Open AccessArticle

Room-Temperature Ammonia Sensor Based on ZnO Nanorods Deposited on ST-Cut Quartz Surface Acoustic Wave Devices

by Wei Li¹, Yuanjun Guo^1,*, Yongliang Tang¹, Xiaotao Zu¹, Jinyi Ma², Lu Wang² and Yong Qing Fu^1,3,*

¹ School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China

² Sichuan Institute of Piezoelectric and Acousto-Optic Technology, Chongqing 400060, China

³ Faculty of Engineering & Environment, University of Northumbria, Newcastle upon Tyne NE1 8ST, UK

Sensors 2017, 17(5), 1142; https://doi.org/10.3390/s17051142 - 17 May 2017

Cited by 23 | Viewed by 6092

Abstract

Using a seed layer-free hydrothermal method, ZnO nanorods (NRs) were deposited on ST-cut quartz surface acoustic wave (SAW) devices for ammonia sensing at room temperature. For a comparison, a ZnO film layer with a thickness of 30 nm was also coated onto an [...] Read more.

Using a seed layer-free hydrothermal method, ZnO nanorods (NRs) were deposited on ST-cut quartz surface acoustic wave (SAW) devices for ammonia sensing at room temperature. For a comparison, a ZnO film layer with a thickness of 30 nm was also coated onto an ST-cut quartz SAW device using a sol-gel and spin-coating technique. The ammonia sensing results showed that the sensitivity, repeatability and stability of the ZnO NR-coated SAW device were superior to those of the ZnO film-coated SAW device due to the large surface-to-volume ratio of the ZnO NRs. Full article

(This article belongs to the Special Issue Acoustic Wave Resonator-Based Sensors)

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19 pages, 3566 KiB

Open AccessArticle

A Hybrid Generalized Hidden Markov Model-Based Condition Monitoring Approach for Rolling Bearings

by Jie Liu¹, Youmin Hu¹, Bo Wu^1,*, Yan Wang² and Fengyun Xie³

¹ School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China

² Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA

³ School of Mechatronics and Vehicle Engineering, East China Jiaotong University, Nanchang 330013, China

Sensors 2017, 17(5), 1143; https://doi.org/10.3390/s17051143 - 18 May 2017

Cited by 28 | Viewed by 5544

Abstract

The operating condition of rolling bearings affects productivity and quality in the rotating machine process. Developing an effective rolling bearing condition monitoring approach is critical to accurately identify the operating condition. In this paper, a hybrid generalized hidden Markov model-based condition monitoring approach [...] Read more.

The operating condition of rolling bearings affects productivity and quality in the rotating machine process. Developing an effective rolling bearing condition monitoring approach is critical to accurately identify the operating condition. In this paper, a hybrid generalized hidden Markov model-based condition monitoring approach for rolling bearings is proposed, where interval valued features are used to efficiently recognize and classify machine states in the machine process. In the proposed method, vibration signals are decomposed into multiple modes with variational mode decomposition (VMD). Parameters of the VMD, in the form of generalized intervals, provide a concise representation for aleatory and epistemic uncertainty and improve the robustness of identification. The multi-scale permutation entropy method is applied to extract state features from the decomposed signals in different operating conditions. Traditional principal component analysis is adopted to reduce feature size and computational cost. With the extracted features’ information, the generalized hidden Markov model, based on generalized interval probability, is used to recognize and classify the fault types and fault severity levels. Finally, the experiment results show that the proposed method is effective at recognizing and classifying the fault types and fault severity levels of rolling bearings. This monitoring method is also efficient enough to quantify the two uncertainty components. Full article

(This article belongs to the Section Physical Sensors)

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17 pages, 3291 KiB

Open AccessArticle

A Two-Echelon Cooperated Routing Problem for a Ground Vehicle and Its Carried Unmanned Aerial Vehicle

by Zhihao Luo^*

, Zhong Liu and Jianmai Shi

Science and Technology on Information System Engineering Laboratory, National University of Defense Technology, Changsha 410073, China

Sensors 2017, 17(5), 1144; https://doi.org/10.3390/s17051144 - 17 May 2017

Cited by 141 | Viewed by 8057

Abstract

In this paper, a two-echelon cooperated routing problem for the ground vehicle (GV) and its carried unmanned aerial vehicle (UAV) is investigated, where the GV travels on the road network and its UAV travels in areas beyond the road to visit a number [...] Read more.

In this paper, a two-echelon cooperated routing problem for the ground vehicle (GV) and its carried unmanned aerial vehicle (UAV) is investigated, where the GV travels on the road network and its UAV travels in areas beyond the road to visit a number of targets unreached by the GV. In contrast to the classical two-echelon routing problem, the UAV has to launch and land on the GV frequently to change or charge its battery while the GV is moving on the road network. A new 0–1 integer programming model is developed to formulate the problem, where the constraints on the spatial and temporal cooperation of GV and UAV routes are included. Two heuristics are proposed to solve the model: the first heuristic (H1) constructs a complete tour for all targets and splits it by GV routes, while the second heuristic (H2) constructs the GV tour and assigns UAV flights to it. Random instances with six different sizes (25–200 targets, 12–80 rendezvous nodes) are used to test the algorithms. Computational results show that H1 performs slightly better than H2, while H2 uses less time and is more stable. Full article

(This article belongs to the Section Remote Sensors)

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25 pages, 6070 KiB

Open AccessArticle

Towards System Calibration of Panoramic Laser Scanners from a Single Station

by Tomislav Medić^*, Christoph Holst

and Heiner Kuhlmann

Institute of Geodesy and Geoinformation, University of Bonn, Nussallee 17, 53115 Bonn, Germany

Sensors 2017, 17(5), 1145; https://doi.org/10.3390/s17051145 - 17 May 2017

Cited by 28 | Viewed by 7959

Abstract

Terrestrial laser scanner measurements suffer from systematic errors due to internal misalignments. The magnitude of the resulting errors in the point cloud in many cases exceeds the magnitude of random errors. Hence, the task of calibrating a laser scanner is important for applications [...] Read more.

Terrestrial laser scanner measurements suffer from systematic errors due to internal misalignments. The magnitude of the resulting errors in the point cloud in many cases exceeds the magnitude of random errors. Hence, the task of calibrating a laser scanner is important for applications with high accuracy demands. This paper primarily addresses the case of panoramic terrestrial laser scanners. Herein, it is proven that most of the calibration parameters can be estimated from a single scanner station without a need for any reference information. This hypothesis is confirmed through an empirical experiment, which was conducted in a large machine hall using a Leica Scan Station P20 panoramic laser scanner. The calibration approach is based on the widely used target-based self-calibration approach, with small modifications. A new angular parameterization is used in order to implicitly introduce measurements in two faces of the instrument and for the implementation of calibration parameters describing genuine mechanical misalignments. Additionally, a computationally preferable calibration algorithm based on the two-face measurements is introduced. In the end, the calibration results are discussed, highlighting all necessary prerequisites for the scanner calibration from a single scanner station. Full article

(This article belongs to the Section Remote Sensors)

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17 pages, 4243 KiB

Open AccessArticle

An Improved Model Predictive Current Controller of Switched Reluctance Machines Using Time-Multiplexed Current Sensor

by Bingchu Li, Xiao Ling, Yixiang Huang, Liang Gong and Chengliang Liu^*

School of Mechanical Engineering, Shanghai JiaoTong University, 800 Dongchuan Road, Minhang Qu, Shanghai 200240, China

Sensors 2017, 17(5), 1146; https://doi.org/10.3390/s17051146 - 17 May 2017

Cited by 10 | Viewed by 5127

Abstract

This paper presents a fixed-switching-frequency model predictive current controller using multiplexed current sensor for switched reluctance machine (SRM) drives. The converter was modified to distinguish currents from simultaneously excited phases during the sampling period. The only current sensor installed in the converter was [...] Read more.

This paper presents a fixed-switching-frequency model predictive current controller using multiplexed current sensor for switched reluctance machine (SRM) drives. The converter was modified to distinguish currents from simultaneously excited phases during the sampling period. The only current sensor installed in the converter was time division multiplexing for phase current sampling. During the commutation stage, the control steps of adjacent phases were shifted so that sampling time was staggered. The maximum and minimum duty ratio of pulse width modulation (PWM) was limited to keep enough sampling time for analog-to-digital (A/D) conversion. Current sensor multiplexing was realized without complex adjustment of either driver circuit nor control algorithms, while it helps to reduce the cost and errors introduced in current sampling due to inconsistency between sensors. The proposed controller is validated by both simulation and experimental results with a 1.5 kW three-phase 12/8 SRM. Satisfied current sampling is received with little difference compared with independent phase current sensors for each phase. The proposed controller tracks the reference current profile as accurately as the model predictive current controller with independent phase current sensors, while having minor tracking errors compared with a hysteresis current controller. Full article

(This article belongs to the Section Physical Sensors)

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11 pages, 31688 KiB

Open AccessArticle

Flexible, Low-Cost Sensor Based on Electrolyte Gated Carbon Nanotube Field Effect Transistor for Organo-Phosphate Detection

by Vijay Deep Bhatt^1,*, Saumya Joshi¹, Markus Becherer¹ and Paolo Lugli²

¹ Department of Electrical Engineering and Information Technology, Institute for Nanoelectronics, Technische Universität München, Munich 80333, Germany

² Faculty of Science and Technology, Free University of Bozen-Bolzano, 39100 Bolzano, Italy

Sensors 2017, 17(5), 1147; https://doi.org/10.3390/s17051147 - 18 May 2017

Cited by 29 | Viewed by 7469

Abstract

A flexible enzymatic acetylcholinesterase biosensor based on an electrolyte-gated carbon nanotube field effect transistor is demonstrated. The enzyme immobilization is done on a planar gold gate electrode using 3-mercapto propionic acid as the linker molecule. The sensor showed good sensing capability as a [...] Read more.

A flexible enzymatic acetylcholinesterase biosensor based on an electrolyte-gated carbon nanotube field effect transistor is demonstrated. The enzyme immobilization is done on a planar gold gate electrode using 3-mercapto propionic acid as the linker molecule. The sensor showed good sensing capability as a sensor for the neurotransmitter acetylcholine, with a sensitivity of 5.7 μA/decade, and demonstrated excellent specificity when tested against interfering analytes present in the body. As the flexible sensor is supposed to suffer mechanical deformations, the endurance of the sensor was measured by putting it under extensive mechanical stress. The enzymatic activity was inhibited by more than 70% when the phosphate-buffered saline (PBS) buffer was spiked with 5 mg/mL malathion (an organophosphate) solution. The biosensor was successfully challenged with tap water and strawberry juice, demonstrating its usefulness as an analytical tool for organophosphate detection. Full article

(This article belongs to the Special Issue Advanced Sensors Based on Carbon Electrodes)

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23 pages, 2465 KiB

Open AccessArticle

Development of a Virtual Collision Sensor for Industrial Robots

by Marina Indri^1,*

, Stefano Trapani¹ and Ivan Lazzero²

¹ Dipartimento di Automatica e Informatica, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino 10129, Italy

² COMAU SpA, Via Rivalta 30, Grugliasco (TO) 10095, Italy

Sensors 2017, 17(5), 1148; https://doi.org/10.3390/s17051148 - 18 May 2017

Cited by 28 | Viewed by 5785

Abstract

Collision detection is a fundamental issue for the safety of a robotic cell. While several common methods require specific sensors or the knowledge of the robot dynamic model, the proposed solution is constituted by a virtual collision sensor for industrial manipulators, which requires [...] Read more.

Collision detection is a fundamental issue for the safety of a robotic cell. While several common methods require specific sensors or the knowledge of the robot dynamic model, the proposed solution is constituted by a virtual collision sensor for industrial manipulators, which requires as inputs only the motor currents measured by the standard sensors that equip a manipulator and the estimated currents provided by an internal dynamic model of the robot (i.e., the one used inside its controller), whose structure, parameters and accuracy are not known. The collision detection is achieved by comparing the absolute value of the current residue with a time-varying, positive-valued threshold function, including an estimate of the model error and a bias term, corresponding to the minimum collision torque to be detected. The value of such a term, defining the sensor sensitivity, can be simply imposed as constant, or automatically customized for a specific robotic application through a learning phase and a subsequent adaptation process, to achieve a more robust and faster collision detection, as well as the avoidance of any false collision warnings, even in case of slow variations of the robot behavior. Experimental results are provided to confirm the validity of the proposed solution, which is already adopted in some industrial scenarios. Full article

(This article belongs to the Section Physical Sensors)

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15 pages, 4738 KiB

Open AccessArticle

Wind Turbine Diagnosis under Variable Speed Conditions Using a Single Sensor Based on the Synchrosqueezing Transform Method

by Yanjie Guo, Xuefeng Chen^*, Shibin Wang, Ruobin Sun and Zhibin Zhao

School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China

Sensors 2017, 17(5), 1149; https://doi.org/10.3390/s17051149 - 18 May 2017

Cited by 32 | Viewed by 5093

Abstract

The gearbox is one of the key components in wind turbines. Gearbox fault signals are usually nonstationary and highly contaminated with noise. The presence of amplitude-modulated and frequency-modulated (AM-FM) characteristics compound the difficulty of precise fault diagnosis of wind turbines, therefore, it is [...] Read more.

The gearbox is one of the key components in wind turbines. Gearbox fault signals are usually nonstationary and highly contaminated with noise. The presence of amplitude-modulated and frequency-modulated (AM-FM) characteristics compound the difficulty of precise fault diagnosis of wind turbines, therefore, it is crucial to develop an effective fault diagnosis method for such equipment. This paper presents an improved diagnosis method for wind turbines via the combination of synchrosqueezing transform and local mean decomposition. Compared to the conventional time-frequency analysis techniques, the improved method which is performed in non-real-time can effectively reduce the noise pollution of the signals and preserve the signal characteristics, and hence is suitable for the analysis of nonstationary signals with high noise. This method is further validated by simulated signals and practical vibration data measured from a 1.5 MW wind turbine. The results confirm that the proposed method can simultaneously control the noise and increase the accuracy of time-frequency representation. Full article

(This article belongs to the Section Physical Sensors)

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12 pages, 3876 KiB

Open AccessArticle

Measuring Dynamic Signals with Direct Sensor-to-Microcontroller Interfaces Applied to a Magnetoresistive Sensor

by Ernesto Sifuentes¹

, Rafael Gonzalez-Landaeta¹

, Juan Cota-Ruiz¹

and Ferran Reverter^2,*

¹ Department of Computer and Electrical Engineering, Universidad Autónoma de Ciudad Juárez (UACJ), 32310 Ciudad Juárez, Mexico

² e-CAT Research Group, Department of Electronic Engineering, Universitat Politècnica de Catalunya (UPC)—BarcelonaTech, C/Esteve Terradas 7, C4, 08860 Castelldefels, Spain

Sensors 2017, 17(5), 1150; https://doi.org/10.3390/s17051150 - 18 May 2017

Cited by 16 | Viewed by 6774

Abstract

This paper evaluates the performance of direct interface circuits (DIC), where the sensor is directly connected to a microcontroller, when a resistive sensor subjected to dynamic changes is measured. The theoretical analysis provides guidelines for the selection of the components taking into account [...] Read more.

This paper evaluates the performance of direct interface circuits (DIC), where the sensor is directly connected to a microcontroller, when a resistive sensor subjected to dynamic changes is measured. The theoretical analysis provides guidelines for the selection of the components taking into account both the desired resolution and the bandwidth of the input signal. Such an analysis reveals that there is a trade-off between the sampling frequency and the resolution of the measurement, and this depends on the selected value of the capacitor that forms the RC circuit together with the sensor resistance. This performance is then experimentally proved with a DIC measuring a magnetoresistive sensor exposed to a magnetic field of different frequencies, amplitudes, and waveforms. A sinusoidal magnetic field up to 1 kHz can be monitored with a resolution of eight bits and a sampling frequency of around 10 kSa/s. If a higher resolution is desired, the sampling frequency has to be lower, thus limiting the bandwidth of the dynamic signal under measurement. The DIC is also applied to measure an electrocardiogram-type signal and its QRS complex is well identified, which enables the estimation, for instance, of the heart rate. Full article

(This article belongs to the Special Issue Autonomous Sensors)

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17 pages, 486 KiB

Open AccessArticle

Optimal Fusion Estimation with Multi-Step Random Delays and Losses in Transmission

by Raquel Caballero-Águila^1,*

, Aurora Hermoso-Carazo² and Josefa Linares-Pérez²

¹ Dpto. de Estadística, Universidad de Jaén, Paraje Las Lagunillas, 23071 Jaén, Spain

² Dpto. de Estadística, Universidad de Granada, Avda. Fuentenueva, 18071 Granada, Spain

Sensors 2017, 17(5), 1151; https://doi.org/10.3390/s17051151 - 18 May 2017

Cited by 15 | Viewed by 4430

Abstract

This paper is concerned with the optimal fusion estimation problem in networked stochastic systems with bounded random delays and packet dropouts, which unavoidably occur during the data transmission in the network. The measured outputs from each sensor are perturbed by random parameter matrices [...] Read more.

This paper is concerned with the optimal fusion estimation problem in networked stochastic systems with bounded random delays and packet dropouts, which unavoidably occur during the data transmission in the network. The measured outputs from each sensor are perturbed by random parameter matrices and white additive noises, which are cross-correlated between the different sensors. Least-squares fusion linear estimators including filter, predictor and fixed-point smoother, as well as the corresponding estimation error covariance matrices are designed via the innovation analysis approach. The proposed recursive algorithms depend on the delay probabilities at each sampling time, but do not to need to know if a particular measurement is delayed or not. Moreover, the knowledge of the signal evolution model is not required, as the algorithms need only the first and second order moments of the processes involved. Some of the practical situations covered by the proposed system model with random parameter matrices are analyzed and the influence of the delays in the estimation accuracy are examined in a numerical example. Full article

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

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10 pages, 2145 KiB

Open AccessArticle

An Improved RD Algorithm for Maneuvering Bistatic Forward-Looking SAR Imaging with a Fixed Transmitter

by Yue Yuan, Si Chen^* and Huichang Zhao

School of Electronic & Optical Engineering, Nanjing University of Science & Technology, Nanjing 210094, China

Sensors 2017, 17(5), 1152; https://doi.org/10.3390/s17051152 - 19 May 2017

Cited by 12 | Viewed by 4603

Abstract

In order to improve the azimuth resolution beyond what monostatic synthetic aperture radar (SAR) can achieve in the forward-looking area, an asymmetric configuration bistatic SAR system and its imaging algorithm are proposed in this paper. The transmitter is mounted on a fixed platform [...] Read more.

In order to improve the azimuth resolution beyond what monostatic synthetic aperture radar (SAR) can achieve in the forward-looking area, an asymmetric configuration bistatic SAR system and its imaging algorithm are proposed in this paper. The transmitter is mounted on a fixed platform in side-looking mode while the receiver moves along a nonlinear trajectory in forward-looking mode. Due to the high velocity and acceleration of the maneuvering platform in both along-track and height direction, the traditional algorithms are no longer applicable. In this paper, a new algorithm based on the high precise 2-D frequency spectrum is proposed, which takes high-order Taylor series expansion terms of the slant range into consideration. The proposed algorithm compensates high-order range-azimuth coupling terms to guarantee the focus accuracy in SAR imaging. The simulation results and error analysis validate the effectiveness of the proposed algorithm and the correctness of our analysis. Full article

(This article belongs to the Section Remote Sensors)

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19 pages, 2784 KiB

Open AccessArticle

Low Power Multi-Hop Networking Analysis in Intelligent Environments

by Josu Etxaniz^*

and Gerardo Aranguren

Electronic Technology Department, University of the Basque Country, Bilbao 48013, Spain

Sensors 2017, 17(5), 1153; https://doi.org/10.3390/s17051153 - 19 May 2017

Cited by 2 | Viewed by 5397

Abstract

Intelligent systems are driven by the latest technological advances in many different areas such as sensing, embedded systems, wireless communications or context recognition. This paper focuses on some of those areas. Concretely, the paper deals with wireless communications issues in embedded systems. More [...] Read more.

Intelligent systems are driven by the latest technological advances in many different areas such as sensing, embedded systems, wireless communications or context recognition. This paper focuses on some of those areas. Concretely, the paper deals with wireless communications issues in embedded systems. More precisely, the paper combines the multi-hop networking with Bluetooth technology and a quality of service (QoS) metric, the latency. Bluetooth is a radio license-free worldwide communication standard that makes low power multi-hop wireless networking available. It establishes piconets (point-to-point and point-to-multipoint links) and scatternets (multi-hop networks). As a result, many Bluetooth nodes can be interconnected to set up ambient intelligent networks. Then, this paper presents the results of the investigation on multi-hop latency with park and sniff Bluetooth low power modes conducted over the hardware test bench previously implemented. In addition, the empirical models to estimate the latency of multi-hop communications over Bluetooth Asynchronous Connectionless Links (ACL) in park and sniff mode are given. The designers of devices and networks for intelligent systems will benefit from the estimation of the latency in Bluetooth multi-hop communications that the models provide. Full article

(This article belongs to the Special Issue System-Integrated Intelligence and Intelligent Systems)

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31 pages, 3467 KiB

Open AccessArticle

Non-Invasive Fetal Monitoring: A Maternal Surface ECG Electrode Placement-Based Novel Approach for Optimization of Adaptive Filter Control Parameters Using the LMS and RLS Algorithms

by Radek Martinek^1,*

, Radana Kahankova¹

, Homer Nazeran², Jaromir Konecny¹, Janusz Jezewski³, Petr Janku⁴, Petr Bilik¹, Jan Zidek¹, Jan Nedoma⁵

and Marcel Fajkus⁵

¹ Department of Cybernetics and Biomedical Engineering, Faculty of Electrical Engineering and Computer Science, VSB-Technical University of Ostrava, 17 Listopadu 15, 70833 Ostrava, Czech Republic

² Department of Electrical and Computer Engineering, University of Texas El Paso, 500 W University Ave, El Paso, TX 79968, USA

³ Institute of Medical Technology and Equipment ITAM, 118 Roosevelt Str., 41-800 Zabrze, Poland

⁴ Department of Obstetrics and Gynecology, Masaryk University and University Hospital Brno, Jihlavska 20, 625 00 Brno, Czech Republic

⁵ Department of Telecommunications, Faculty of Electrical Engineering and Computer Science, VSB-Technical University of Ostrava, 17 Listopadu 15, 70833 Ostrava, Czech Republic

Sensors 2017, 17(5), 1154; https://doi.org/10.3390/s17051154 - 19 May 2017

Cited by 89 | Viewed by 11926

Abstract

This paper is focused on the design, implementation and verification of a novel method for the optimization of the control parameters (such as step size

μ

and filter order N) of LMS and RLS adaptive filters used for noninvasive fetal monitoring. The [...] Read more.

This paper is focused on the design, implementation and verification of a novel method for the optimization of the control parameters (such as step size

μ

and filter order N) of LMS and RLS adaptive filters used for noninvasive fetal monitoring. The optimization algorithm is driven by considering the ECG electrode positions on the maternal body surface in improving the performance of these adaptive filters. The main criterion for optimal parameter selection was the Signal-to-Noise Ratio (SNR). We conducted experiments using signals supplied by the latest version of our LabVIEW-Based Multi-Channel Non-Invasive Abdominal Maternal-Fetal Electrocardiogram Signal Generator, which provides the flexibility and capability of modeling the principal distribution of maternal/fetal ECGs in the human body. Our novel algorithm enabled us to find the optimal settings of the adaptive filters based on maternal surface ECG electrode placements. The experimental results further confirmed the theoretical assumption that the optimal settings of these adaptive filters are dependent on the ECG electrode positions on the maternal body, and therefore, we were able to achieve far better results than without the use of optimization. These improvements in turn could lead to a more accurate detection of fetal hypoxia. Consequently, our approach could offer the potential to be used in clinical practice to establish recommendations for standard electrode placement and find the optimal adaptive filter settings for extracting high quality fetal ECG signals for further processing. Ultimately, diagnostic-grade fetal ECG signals would ensure the reliable detection of fetal hypoxia. Full article

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

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11 pages, 4467 KiB

Open AccessArticle

Structural Analysis of Polymer Composites Using Spectral Domain Optical Coherence Tomography

by Muhammad Faizan Shirazi¹

, Mansik Jeon^1,* and Jeehyun Kim^1,2

¹ School of Electronics Engineering, College of IT Engineering, Kyungpook National University, 80 Daehak-ro, Bukgu, Daegu 41566, Korea

² Oz-tec Co. Ltd., Office 901, IT Convergence Industrial Building, 47 Gyeongdae-ro, 17-gil, Bukgu, Daegu 41566, Korea

Sensors 2017, 17(5), 1155; https://doi.org/10.3390/s17051155 - 18 May 2017

Cited by 11 | Viewed by 5641

Abstract

The structural analysis of nylon/graphene oxide (NY/GO) and polyetherblockamide/ trisilinolphenyl-polyhederal oligomeric silsesquioxane (PEBA/t-POSS) composites were performed using high-resolution spectral domain optical coherence tomography (SD-OCT). This optical technology revealed both cross-sectional, as well as sub-layer depth information of sample. The non-destructive real-time imaging demonstrated [...] Read more.

The structural analysis of nylon/graphene oxide (NY/GO) and polyetherblockamide/ trisilinolphenyl-polyhederal oligomeric silsesquioxane (PEBA/t-POSS) composites were performed using high-resolution spectral domain optical coherence tomography (SD-OCT). This optical technology revealed both cross-sectional, as well as sub-layer depth information of sample. The non-destructive real-time imaging demonstrated the nature of defects in the composites. The thickness and location of each defect point in the composites were measured using A-scan analysis on the SD-OCT images. The cross-sectional and volumetric images clearly demonstrate the effectiveness of SD-OCT for composite research, as well as the for industrial quality assurance of polymer materials. Full article

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

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22 pages, 11085 KiB

Open AccessArticle

Bath-Ambience—A Mechatronic System for Assisting the Caregivers of Bedridden People

by Karolina Bezerra^1,2, José Machado^1,2,*

, Vítor Carvalho^3,4

, Marcelo Castro², Pedro Costa², Demétrio Matos^1,4

and Filomena Soares³

¹ MEtRICs Research Center, School of Engineering, University of Minho, 4800-058 Guimarães, Portugal

² Mechanical Engineering Department, School of Engineering, University of Minho, 4800-058 Guimarães, Portugal

³ R&D ALGORITMI Centre, School of Engineering, University of Minho, 4800-058 Guimarães, Portugal

⁴ IPCA, Polytechnic Institute of Cávado and Ave, Vila Frescainha S. Martinho, 4750-810 Barcelos, Portugal

Sensors 2017, 17(5), 1156; https://doi.org/10.3390/s17051156 - 18 May 2017

Cited by 11 | Viewed by 6678

Abstract

The health of older people is receiving special attention and dedication nowadays, with the aim of increasing their general wellbeing and quality of life. Studies into different aspects of the care of the elderly have found that emphasis should be given to solving [...] Read more.

The health of older people is receiving special attention and dedication nowadays, with the aim of increasing their general wellbeing and quality of life. Studies into different aspects of the care of the elderly have found that emphasis should be given to solving problems related to bathing in different situations and environments. In particular, it is important to develop new assistive technologies to streamline and ease the burden of a caregiver’s daily tasks. Generally-speaking, in the case of bedridden patients, bathing is typically carried out manually by a caregiver, using towels, sponges, and a water basin. Nevertheless, this apparently simple task needs some precautions in order to avoid the risk of microbial infections, falls and other injuries. With that in mind, this paper presents the design of a portable washing system, called Bath-Ambience, which enables bedridden patients to be bathed efficiently without having to be moved from their position. This portable system can be installed in different situations, both in a domestic setting, and in specialized institutions, and allows the caregiver to perform the bathing tasks without compromising health and safety, thereby making it possible to offer a comfortable and hygienic procedure to patients, improving their quality of life. This paper presents the design of the portable Bath-Ambience washing system, which provides efficient assistance for bathing bedridden patients without moving them to another place. This system is mainly dedicated for integration a smart home application in to allow bathing everywhere. Full article

(This article belongs to the Section Physical Sensors)

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21 pages, 5320 KiB

Open AccessArticle

Infrared Thermography Sensor for Temperature and Speed Measurement of Moving Material

by Rubén Usamentiaga^*

and Daniel Fernando García

Department of Computer Science and Engineering, University of Oviedo, Campus de Viesques, 33204 Gijón, Spain

Sensors 2017, 17(5), 1157; https://doi.org/10.3390/s17051157 - 18 May 2017

Cited by 18 | Viewed by 5871

Abstract

Infrared thermography offers significant advantages in monitoring the temperature of objects over time, but crucial aspects need to be addressed. Movements between the infrared camera and the inspected material seriously affect the accuracy of the calculated temperature. These movements can be the consequence [...] Read more.

Infrared thermography offers significant advantages in monitoring the temperature of objects over time, but crucial aspects need to be addressed. Movements between the infrared camera and the inspected material seriously affect the accuracy of the calculated temperature. These movements can be the consequence of solid objects that are moved, molten metal poured, material on a conveyor belt, or just vibrations. This work proposes a solution for monitoring the temperature of material in these scenarios. In this work both real movements and vibrations are treated equally, proposing a unified solution for both problems. The three key steps of the proposed procedure are image rectification, motion estimation and motion compensation. Image rectification calculates a front-parallel projection of the image that simplifies the estimation and compensation of the movement. Motion estimation describes the movement using a mathematical model, and estimates the coefficients using robust methods adapted to infrared images. Motion is finally compensated for in order to produce the correct temperature time history of the monitored material regardless of the movement. The result is a robust sensor for temperature of moving material that can also be used to measure the speed of the material. Different experiments are carried out to validate the proposed method in laboratory and real environments. Results show excellent performance. Full article

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

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7 pages, 1783 KiB

Open AccessArticle

Development towards Compact Nitrocellulose-Based Interferometric Biochips for Dry Eye MMP9 Label-Free In-Situ Diagnosis

by Beatriz Santamaría¹, María F. Laguna^1,*, David López-Romero², Ana L. Hernandez¹, Francisco J. Sanza², Álvaro Lavín¹, Rafael Casquel¹, María V. Maigler², Rocío L. Espinosa¹ and Miguel Holgado¹

¹ Centre for Biomedical Technology, Optics, Photonics and Biophotinics Laboratory, Campus Montegancedo, Universidad Politécnica de Madrid, 28223 Madrid, Spain

² BioOptical Detection, Centro de Empresas, Campus Montegancedo, 28223 Madrid, Spain

Sensors 2017, 17(5), 1158; https://doi.org/10.3390/s17051158 - 19 May 2017

Cited by 16 | Viewed by 7097

Abstract

A novel compact optical biochip based on a thin layer-sensing surface of nitrocellulose is used for in-situ label-free detection of metalloproteinase (MMP9) related to dry eye disease. In this article, a new integrated chip with different interferometric transducers layout with an optimal sensing [...] Read more.

A novel compact optical biochip based on a thin layer-sensing surface of nitrocellulose is used for in-situ label-free detection of metalloproteinase (MMP9) related to dry eye disease. In this article, a new integrated chip with different interferometric transducers layout with an optimal sensing surface is reported for the first time. We demonstrate that specific antibodies can be immobilized onto these transducers with a very low volume of sample and with good orientation. Many sensing transducers constitute the presented biochip in order to yield statistical data and stability in the acquired measurements. As a result, we report the recognition curve for pure recombinant MMP9, tests of model tears with MMP9, and real tear performance from patients, with a promising limit of detection. Full article

(This article belongs to the Section Biosensors)

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17 pages, 1695 KiB

Open AccessArticle

Optimization-Based Sensor Fusion of GNSS and IMU Using a Moving Horizon Approach

by Fabian Girrbach^1,2,*, Jeroen D. Hol¹, Giovanni Bellusci¹

and Moritz Diehl²

¹ Xsens Technologies B.V., Enschede 7521 PR, The Netherlands

² Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110 Freiburg, Germany

Sensors 2017, 17(5), 1159; https://doi.org/10.3390/s17051159 - 19 May 2017

Cited by 13 | Viewed by 8404

Abstract

The rise of autonomous systems operating close to humans imposes new challenges in terms of robustness and precision on the estimation and control algorithms. Approaches based on nonlinear optimization, such as moving horizon estimation, have been shown to improve the accuracy of the [...] Read more.

The rise of autonomous systems operating close to humans imposes new challenges in terms of robustness and precision on the estimation and control algorithms. Approaches based on nonlinear optimization, such as moving horizon estimation, have been shown to improve the accuracy of the estimated solution compared to traditional filter techniques. This paper introduces an optimization-based framework for multi-sensor fusion following a moving horizon scheme. The framework is applied to the often occurring estimation problem of motion tracking by fusing measurements of a global navigation satellite system receiver and an inertial measurement unit. The resulting algorithm is used to estimate position, velocity, and orientation of a maneuvering airplane and is evaluated against an accurate reference trajectory. A detailed study of the influence of the horizon length on the quality of the solution is presented and evaluated against filter-like and batch solutions of the problem. The versatile configuration possibilities of the framework are finally used to analyze the estimated solutions at different evaluation times exposing a nearly linear behavior of the sensor fusion problem. Full article

(This article belongs to the Special Issue Multi-Sensor Integration and Fusion)

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15 pages, 2318 KiB

Open AccessArticle

ROI-Based On-Board Compression for Hyperspectral Remote Sensing Images on GPU

by Rossella Giordano and Pietro Guccione^*

Department of Electrical and Information Engineering, Politecnico di Bari, 70125 Bari, Italy

Sensors 2017, 17(5), 1160; https://doi.org/10.3390/s17051160 - 19 May 2017

Cited by 16 | Viewed by 5357

Abstract

In recent years, hyperspectral sensors for Earth remote sensing have become very popular. Such systems are able to provide the user with images having both spectral and spatial information. The current hyperspectral spaceborne sensors are able to capture large areas with increased spatial [...] Read more.

In recent years, hyperspectral sensors for Earth remote sensing have become very popular. Such systems are able to provide the user with images having both spectral and spatial information. The current hyperspectral spaceborne sensors are able to capture large areas with increased spatial and spectral resolution. For this reason, the volume of acquired data needs to be reduced on board in order to avoid a low orbital duty cycle due to limited storage space. Recently, literature has focused the attention on efficient ways for on-board data compression. This topic is a challenging task due to the difficult environment (outer space) and due to the limited time, power and computing resources. Often, the hardware properties of Graphic Processing Units (GPU) have been adopted to reduce the processing time using parallel computing. The current work proposes a framework for on-board operation on a GPU, using NVIDIA’s CUDA (Compute Unified Device Architecture) architecture. The algorithm aims at performing on-board compression using the target’s related strategy. In detail, the main operations are: the automatic recognition of land cover types or detection of events in near real time in regions of interest (this is a user related choice) with an unsupervised classifier; the compression of specific regions with space-variant different bit rates including Principal Component Analysis (PCA), wavelet and arithmetic coding; and data volume management to the Ground Station. Experiments are provided using a real dataset taken from an AVIRIS (Airborne Visible/Infrared Imaging Spectrometer) airborne sensor in a harbor area. Full article

(This article belongs to the Section Remote Sensors)

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18 pages, 4206 KiB

Open AccessArticle

An Adaptive Orientation Estimation Method for Magnetic and Inertial Sensors in the Presence of Magnetic Disturbances

by Bingfei Fan¹

, Qingguo Li², Chao Wang¹ and Tao Liu^1,*

¹ State Key Laboratory of Fluid Power and Mechatronic Systems, School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China

² Department of Mechanical and Materials Engineering, Queen’s University, Kingston, ON K7L 3N6, Canada

Sensors 2017, 17(5), 1161; https://doi.org/10.3390/s17051161 - 19 May 2017

Cited by 40 | Viewed by 7499

Abstract

Magnetic and inertial sensors have been widely used to estimate the orientation of human segments due to their low cost, compact size and light weight. However, the accuracy of the estimated orientation is easily affected by external factors, especially when the sensor is [...] Read more.

Magnetic and inertial sensors have been widely used to estimate the orientation of human segments due to their low cost, compact size and light weight. However, the accuracy of the estimated orientation is easily affected by external factors, especially when the sensor is used in an environment with magnetic disturbances. In this paper, we propose an adaptive method to improve the accuracy of orientation estimations in the presence of magnetic disturbances. The method is based on existing gradient descent algorithms, and it is performed prior to sensor fusion algorithms. The proposed method includes stationary state detection and magnetic disturbance severity determination. The stationary state detection makes this method immune to magnetic disturbances in stationary state, while the magnetic disturbance severity determination helps to determine the credibility of magnetometer data under dynamic conditions, so as to mitigate the negative effect of the magnetic disturbances. The proposed method was validated through experiments performed on a customized three-axis instrumented gimbal with known orientations. The error of the proposed method and the original gradient descent algorithms were calculated and compared. Experimental results demonstrate that in stationary state, the proposed method is completely immune to magnetic disturbances, and in dynamic conditions, the error caused by magnetic disturbance is reduced by 51.2% compared with original MIMU gradient descent algorithm. Full article

(This article belongs to the Special Issue Wearable and Ambient Sensors for Healthcare and Wellness Applications)

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15 pages, 2133 KiB

Open AccessArticle

Property Analysis of the Real-Time Uncalibrated Phase Delay Product Generated by Regional Reference Stations and Its Influence on Precise Point Positioning Ambiguity Resolution

by Yong Zhang¹, Qing Wang^1,* and Xinyuan Jiang²

¹ School of Instrument Science and Engineering, Southeast University, Nanjing 210096, China

² Germany Research Center For Geosciences (GFZ), Telgrafenberg, 14473 Potsdam, Germany

Sensors 2017, 17(5), 1162; https://doi.org/10.3390/s17051162 - 19 May 2017

Cited by 4 | Viewed by 5234

Abstract

The real-time estimation of the wide-lane and narrow-lane Uncalibrated Phase Delay (UPD) of satellites is realized by real-time data received from regional reference station networks; The properties of the real-time UPD product and its influence on real-time precise point positioning ambiguity resolution (RTPPP-AR) [...] Read more.

The real-time estimation of the wide-lane and narrow-lane Uncalibrated Phase Delay (UPD) of satellites is realized by real-time data received from regional reference station networks; The properties of the real-time UPD product and its influence on real-time precise point positioning ambiguity resolution (RTPPP-AR) are experimentally analyzed according to real-time data obtained from the regional Continuously Operating Reference Stations (CORS) network located in Tianjin, Shanghai, Hong Kong, etc. The results show that the real-time wide-lane and narrow-lane UPD products differ significantly from each other in time-domain characteristics; the wide-lane UPDs have daily stability, with a change rate of less than 0.1 cycle/day, while the narrow-lane UPDs have short-term stability, with significant change in one day. The UPD products generated by different regional networks have obvious spatial characteristics, thus significantly influencing RTPPP-AR: the adoption of real-time UPD products employing the sparse stations in the regional network for estimation is favorable for improving the regional RTPPP-AR up to 99%; the real-time UPD products of different regional networks slightly influence PPP-AR positioning accuracy. After ambiguities are successfully fixed, the real-time dynamic RTPPP-AR positioning accuracy is better than 3 cm in the plane and 8 cm in the upward direction. Full article

(This article belongs to the Section Remote Sensors)

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15 pages, 4008 KiB

Open AccessArticle

Development and Design of Next-Generation Head-Mounted Ambulatory Microdose Positron-Emission Tomography (AM-PET) System

by Samantha Melroy¹, Christopher Bauer², Matthew McHugh³, Garret Carden¹, Alexander Stolin⁴, Stan Majewski⁵, Julie Brefczynski-Lewis⁶ and Thorsten Wuest^1,*

¹ Industrial and Management Systems Engineering, West Virginia University, Morgantown, WV 26506, USA

² Montgomery-Downs Lab, Blanchette Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, USA

³ Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26506, USA

⁴ Department of Radiology, Center for Advanced Imaging, West Virginia University, Morgantown, WV 26506, USA

⁵ Department of Radiology & Medical Imaging, University of Virginia, Charlottesville, VA 22903, USA

⁶ Physiology & Pharmacology & Blanchette Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, USA

Sensors 2017, 17(5), 1164; https://doi.org/10.3390/s17051164 - 19 May 2017

Cited by 30 | Viewed by 9054

Abstract

Several applications exist for a whole brain positron-emission tomography (PET) brain imager designed as a portable unit that can be worn on a patient’s head. Enabled by improvements in detector technology, a lightweight, high performance device would allow PET brain imaging in different [...] Read more.

Several applications exist for a whole brain positron-emission tomography (PET) brain imager designed as a portable unit that can be worn on a patient’s head. Enabled by improvements in detector technology, a lightweight, high performance device would allow PET brain imaging in different environments and during behavioral tasks. Such a wearable system that allows the subjects to move their heads and walk—the Ambulatory Microdose PET (AM-PET)—is currently under development. This imager will be helpful for testing subjects performing selected activities such as gestures, virtual reality activities and walking. The need for this type of lightweight mobile device has led to the construction of a proof of concept portable head-worn unit that uses twelve silicon photomultiplier (SiPM) PET module sensors built into a small ring which fits around the head. This paper is focused on the engineering design of mechanical support aspects of the AM-PET project, both of the current device as well as of the coming next-generation devices. The goal of this work is to optimize design of the scanner and its mechanics to improve comfort for the subject by reducing the effect of weight, and to enable diversification of its applications amongst different research activities. Full article

(This article belongs to the Special Issue System-Integrated Intelligence and Intelligent Systems)

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22 pages, 5231 KiB

Open AccessArticle

PHROG: A Multimodal Feature for Place Recognition

by Fabien Bonardi^1,*

, Samia Ainouz¹, Rémi Boutteau²

, Yohan Dupuis³, Xavier Savatier²

and Pascal Vasseur¹

¹ Laboratoire d’Informatique, de Traitement de l’Information et des Systèmes, Normandie University, UNIROUEN, UNIHAVRE, INSA Rouen, LITIS, 76000 Rouen, France

² Institut de Recherche en Systèmes Électroniques Embarqués, Normandie University, UNIROUEN, ESIGELEC, IRSEEM, 76000 Rouen, France

³ Centre d’Études et d’Expertise sur les Risques, l’Environnement, la Mobilité et l’Aménagement, CEREMA, 76000 Rouen, France

Sensors 2017, 17(5), 1167; https://doi.org/10.3390/s17051167 - 20 May 2017

Cited by 6 | Viewed by 6391

Abstract

Long-term place recognition in outdoor environments remains a challenge due to high appearance changes in the environment. The problem becomes even more difficult when the matching between two scenes has to be made with information coming from different visual sources, particularly with different [...] Read more.

Long-term place recognition in outdoor environments remains a challenge due to high appearance changes in the environment. The problem becomes even more difficult when the matching between two scenes has to be made with information coming from different visual sources, particularly with different spectral ranges. For instance, an infrared camera is helpful for night vision in combination with a visible camera. In this paper, we emphasize our work on testing usual feature point extractors under both constraints: repeatability across spectral ranges and long-term appearance. We develop a new feature extraction method dedicated to improve the repeatability across spectral ranges. We conduct an evaluation of feature robustness on long-term datasets coming from different imaging sources (optics, sensors size and spectral ranges) with a Bag-of-Words approach. The tests we perform demonstrate that our method brings a significant improvement on the image retrieval issue in a visual place recognition context, particularly when there is a need to associate images from various spectral ranges such as infrared and visible: we have evaluated our approach using visible, Near InfraRed (NIR), Short Wavelength InfraRed (SWIR) and Long Wavelength InfraRed (LWIR). Full article

(This article belongs to the Section Physical Sensors)

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17 pages, 703 KiB

Open AccessArticle

Virtual-Lattice Based Intrusion Detection Algorithm over Actuator-Assisted Underwater Wireless Sensor Networks

by Jing Yan^1,2,*, Xiaolei Li¹, Xiaoyuan Luo¹

and Xinping Guan²

¹ Institute of Electrical Engineering, Yanshan University, Qinhuangdao 066004, China

² Department of Automation, Shanghai Jiao Tong University, Shanghai 200240, China

Sensors 2017, 17(5), 1168; https://doi.org/10.3390/s17051168 - 20 May 2017

Cited by 18 | Viewed by 6141

Abstract

Due to the lack of a physical line of defense, intrusion detection becomes one of the key issues in applications of underwater wireless sensor networks (UWSNs), especially when the confidentiality has prime importance. However, the resource-constrained property of UWSNs such as sparse deployment [...] Read more.

Due to the lack of a physical line of defense, intrusion detection becomes one of the key issues in applications of underwater wireless sensor networks (UWSNs), especially when the confidentiality has prime importance. However, the resource-constrained property of UWSNs such as sparse deployment and energy constraint makes intrusion detection a challenging issue. This paper considers a virtual-lattice-based approach to the intrusion detection problem in UWSNs. Different from most existing works, the UWSNs consist of two kinds of nodes, i.e., sensor nodes (SNs), which cannot move autonomously, and actuator nodes (ANs), which can move autonomously according to the performance requirement. With the cooperation of SNs and ANs, the intruder detection probability is defined. Then, a virtual lattice-based monitor (VLM) algorithm is proposed to detect the intruder. In order to reduce the redundancy of communication links and improve detection probability, an optimal and coordinative lattice-based monitor patrolling (OCLMP) algorithm is further provided for UWSNs, wherein an equal price search strategy is given for ANs to find the shortest patrolling path. Under VLM and OCLMP algorithms, the detection probabilities are calculated, while the topology connectivity can be guaranteed. Finally, simulation results are presented to show that the proposed method in this paper can improve the detection accuracy and save the energy consumption compared with the conventional methods. Full article

(This article belongs to the Special Issue Sensing Technologies for Autonomy and Cooperation in Underwater Networked Robot Systems)

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11 pages, 2167 KiB

Open AccessArticle

Fully-Polymeric pH Sensor Realized by Means of a Single-Step Soft Embossing Technique

by Paola Fanzio^1,*, Chi-Tung Chang¹, Maciej Skolimowski², Simone Tanzi² and Luigi Sasso¹

¹ Department of Precision and Microsystems Engineering (PME), Delft University of Technology, 2628 CD Delft, The Netherlands

² Micronit Microtechnologies B.V., 7521 PV Enschede, The Netherlands

Sensors 2017, 17(5), 1169; https://doi.org/10.3390/s17051169 - 20 May 2017

Cited by 15 | Viewed by 5659

Abstract

We present here an electrochemical sensor microsystem for the monitoring of pH. The all-polymeric device is comprised of a cyclic olefin copolymer substrate, a 200 nm-thin patterned layer of conductive polymer (PEDOT), and a 70 nm electropolymerized layer of a pH sensitive conductive [...] Read more.

We present here an electrochemical sensor microsystem for the monitoring of pH. The all-polymeric device is comprised of a cyclic olefin copolymer substrate, a 200 nm-thin patterned layer of conductive polymer (PEDOT), and a 70 nm electropolymerized layer of a pH sensitive conductive polymer (polyaniline). The patterning of the fluidic (microfluidic channels) and conductive (wiring and electrodes) functional elements was achieved with a single soft PDMS mold via a single embossing step process. A post-processing treatment with ethylene glycol assured the functional enhancement of the electrodes, as demonstrated via an electrical and electrochemical characterization. A surface modification of the electrodes was carried out, based on voltammetric electropolymerization, to obtain a thin layer of polyaniline. The mechanism for pH sensing is based on the redox reactions of the polyaniline layer caused by protonation. The sensing performance of the microsystem was finally validated by monitoring its potentiometric response upon exposure to a relevant range of pH. Full article

(This article belongs to the Section Chemical Sensors)

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13 pages, 310 KiB

Open AccessArticle

A Low-Complexity DOA and Polarization Method of Polarization-Sensitive Array

by Wen Dong, Ming Diao, Lipeng Gao^* and Lutao Liu

College of Information and Communication Engineering, Harbin Engineering University, Harbin 150001, China

Sensors 2017, 17(5), 1170; https://doi.org/10.3390/s17051170 - 20 May 2017

Cited by 9 | Viewed by 4928

Abstract

This paper proposes a low-complexity method to estimate the direction of arrival and polarization based on the polarization sensitive array (PSA) which is composed of cross-dipoles. We built a half-quaternions model through the Cayley–Dickson form to remove the redundant information. Then, the directions [...] Read more.

This paper proposes a low-complexity method to estimate the direction of arrival and polarization based on the polarization sensitive array (PSA) which is composed of cross-dipoles. We built a half-quaternions model through the Cayley–Dickson form to remove the redundant information. Then, the directions of arrival (DOAs) were estimated via the root-MUSIC algorithm. Finally, the polarizations were estimated by generalized eigenvalue method. Unlike some existing searching algorithms, such as multiple signal classification (MUSIC), this method can avoid the peak searching and maintains high estimation accuracy. Moreover, we use the oblique projection operators to filter out the interference signals which are decoys of the target signal. Simulation results demonstrate the effectiveness and favorable performance of the proposed method. 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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16 pages, 4794 KiB

Open AccessArticle

Bodily Expression Support for Creative Dance Education by Grasping-Type Musical Interface with Embedded Motion and Grasp Sensors

by Tomoyuki Yamaguchi^1,* and Hideki Kadone²

¹ Department of Intelligent Interaction Technologies, University of Tsukuba, Tsukuba 305-8573, Japan

² Center for Innovative Medicine and Engineering, University of Tsukuba, Tsukuba 305-8577, Japan

Sensors 2017, 17(5), 1171; https://doi.org/10.3390/s17051171 - 20 May 2017

Cited by 9 | Viewed by 6439

Abstract

Dance has been made mandatory as one of the physical education courses in Japan because it can cultivate capacities for expression and communication. Among several types of dance education, creative dance especially contributes to the cultivation of these capacities. However, creative dance requires [...] Read more.

Dance has been made mandatory as one of the physical education courses in Japan because it can cultivate capacities for expression and communication. Among several types of dance education, creative dance especially contributes to the cultivation of these capacities. However, creative dance requires some level of particular skills, as well as creativity, and it is difficult to presuppose these pre-requisites in beginner-level dancers without experience. We propose a novel supporting device for dance beginners to encourage creative dance performance by continuously generating musical sounds in real-time in accordance with their bodily movements. It has embedded sensors developed for this purpose. Experiments to evaluate the effectiveness of the device were conducted with ten beginner-level dancers. Using the proposed device, the subjects demonstrated enhanced creative dance movements with greater variety, evaluated in terms of Laban dance movement description. Also, using the device, they performed with better accuracy and repeatability in a task where they produced an imagined circular trajectory by hand. The proposed interface is effective in terms of creative dance activity and accuracy of motion generation for beginner-level dancers. 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, 1967 KiB

Open AccessArticle

Characterizing Dynamic Walking Patterns and Detecting Falls with Wearable Sensors Using Gaussian Process Methods

by Taehwan Kim¹, Jeongho Park¹, Seongman Heo¹, Keehoon Sung² and Jooyoung Park^1,*

¹ Department of Control and Instrumentation Engineering, Korea University, Sejong-Ro 2511, Sejong-City 30016, Korea

² Research Institute of Korean Air Lines Co., Ltd., Daejeon-City 34054, Korea

Sensors 2017, 17(5), 1172; https://doi.org/10.3390/s17051172 - 20 May 2017

Cited by 16 | Viewed by 5828

Abstract

By incorporating a growing number of sensors and adopting machine learning technologies, wearable devices have recently become a prominent health care application domain. Among the related research topics in this field, one of the most important issues is detecting falls while walking. Since [...] Read more.

By incorporating a growing number of sensors and adopting machine learning technologies, wearable devices have recently become a prominent health care application domain. Among the related research topics in this field, one of the most important issues is detecting falls while walking. Since such falls may lead to serious injuries, automatically and promptly detecting them during daily use of smartphones and/or smart watches is a particular need. In this paper, we investigate the use of Gaussian process (GP) methods for characterizing dynamic walking patterns and detecting falls while walking with built-in wearable sensors in smartphones and/or smartwatches. For the task of characterizing dynamic walking patterns in a low-dimensional latent feature space, we propose a novel approach called auto-encoded Gaussian process dynamical model, in which we combine a GP-based state space modeling method with a nonlinear dimensionality reduction method in a unique manner. The Gaussian process methods are fit for this task because one of the most import strengths of the Gaussian process methods is its capability of handling uncertainty in the model parameters. Also for detecting falls while walking, we propose to recycle the latent samples generated in training the auto-encoded Gaussian process dynamical model for GP-based novelty detection, which can lead to an efficient and seamless solution to the detection task. Experimental results show that the combined use of these GP-based methods can yield promising results for characterizing dynamic walking patterns and detecting falls while walking with the wearable sensors. Full article

(This article belongs to the Special Issue Wearable and Ambient Sensors for Healthcare and Wellness Applications)

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29 pages, 11623 KiB

Open AccessArticle

Eyes of Things

by Oscar Deniz^1,*

, Noelia Vallez¹, Jose L. Espinosa-Aranda¹

, Jose M. Rico-Saavedra¹, Javier Parra-Patino¹, Gloria Bueno¹

, David Moloney², Alireza Dehghani², Aubrey Dunne², Alain Pagani³, Stephan Krauss³, Ruben Reiser³, Martin Waeny⁴, Matteo Sorci⁵, Tim Llewellynn⁵, Christian Fedorczak⁶

, Thierry Larmoire⁶, Marco Herbst⁷, Andre Seirafi⁸ and Kasra Seirafi⁸

¹ VISILAB, University of Castilla-La Mancha, E.T.S.I.Industriales, Avda Camilo Jose Cela s/n, Ciudad Real 13071, Spain

² Movidius, 1st Floor, O’Connell Bridge House, D’Olier Street, Dublin 2, Ireland

³ DFKI, Augmented Vision Research Group, Tripstaddterstr. 122, 67663 Kaiserslautern, Germany

⁴ Awaiba, Madeira Tecnopolo, 9020-105 Funchal, Portugal

⁵ nViso SA, PSE-D, Site EPFL, CH-1015 Lausanne, Switzerland

⁶ THALES Communications & Security, 4 Avenue des Louvresses, 92230 Gennevilliers, France

⁷ Evercam, 6-7 Granby Row, Dublin 1, D01 FW20, Ireland

⁸ Fluxguide, Burggasse 7-9/9, 1070 Vienna, Austria

Sensors 2017, 17(5), 1173; https://doi.org/10.3390/s17051173 - 21 May 2017

Cited by 17 | Viewed by 16999

Abstract

Embedded systems control and monitor a great deal of our reality. While some “classic” features are intrinsically necessary, such as low power consumption, rugged operating ranges, fast response and low cost, these systems have evolved in the last few years to emphasize connectivity [...] Read more.

Embedded systems control and monitor a great deal of our reality. While some “classic” features are intrinsically necessary, such as low power consumption, rugged operating ranges, fast response and low cost, these systems have evolved in the last few years to emphasize connectivity functions, thus contributing to the Internet of Things paradigm. A myriad of sensing/computing devices are being attached to everyday objects, each able to send and receive data and to act as a unique node in the Internet. Apart from the obvious necessity to process at least some data at the edge (to increase security and reduce power consumption and latency), a major breakthrough will arguably come when such devices are endowed with some level of autonomous “intelligence”. Intelligent computing aims to solve problems for which no efficient exact algorithm can exist or for which we cannot conceive an exact algorithm. Central to such intelligence is Computer Vision (CV), i.e., extracting meaning from images and video. While not everything needs CV, visual information is the richest source of information about the real world: people, places and things. The possibilities of embedded CV are endless if we consider new applications and technologies, such as deep learning, drones, home robotics, intelligent surveillance, intelligent toys, wearable cameras, etc. This paper describes the Eyes of Things (EoT) platform, a versatile computer vision platform tackling those challenges and opportunities. Full article

(This article belongs to the Special Issue New Generation Sensors Enabling and Fostering IoT)

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30 pages, 5969 KiB

Open AccessArticle

AEKF-SLAM: A New Algorithm for Robotic Underwater Navigation

by Xin Yuan^*

, José-Fernán Martínez-Ortega, José Antonio Sánchez Fernández and Martina Eckert

Centro de Investigación en Tecnologías Software y Sistemas para la Sostenibilidad (CITSEM), Campus Sur, Universidad Politécnica de Madrid (UPM), Madrid 28031, Spain

Sensors 2017, 17(5), 1174; https://doi.org/10.3390/s17051174 - 21 May 2017

Cited by 43 | Viewed by 12994

Abstract

In this work, we focus on key topics related to underwater Simultaneous Localization and Mapping (SLAM) applications. Moreover, a detailed review of major studies in the literature and our proposed solutions for addressing the problem are presented. The main goal of this paper [...] Read more.

In this work, we focus on key topics related to underwater Simultaneous Localization and Mapping (SLAM) applications. Moreover, a detailed review of major studies in the literature and our proposed solutions for addressing the problem are presented. The main goal of this paper is the enhancement of the accuracy and robustness of the SLAM-based navigation problem for underwater robotics with low computational costs. Therefore, we present a new method called AEKF-SLAM that employs an Augmented Extended Kalman Filter (AEKF)-based SLAM algorithm. The AEKF-based SLAM approach stores the robot poses and map landmarks in a single state vector, while estimating the state parameters via a recursive and iterative estimation-update process. Hereby, the prediction and update state (which exist as well in the conventional EKF) are complemented by a newly proposed augmentation stage. Applied to underwater robot navigation, the AEKF-SLAM has been compared with the classic and popular FastSLAM 2.0 algorithm. Concerning the dense loop mapping and line mapping experiments, it shows much better performances in map management with respect to landmark addition and removal, which avoid the long-term accumulation of errors and clutters in the created map. Additionally, the underwater robot achieves more precise and efficient self-localization and a mapping of the surrounding landmarks with much lower processing times. Altogether, the presented AEKF-SLAM method achieves reliably map revisiting, and consistent map upgrading on loop closure. Full article

(This article belongs to the Special Issue Sensing Technologies for Autonomy and Cooperation in Underwater Networked Robot Systems)

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10 pages, 5032 KiB

Open AccessArticle

A Stretchable Electromagnetic Absorber Fabricated Using Screen Printing Technology

by Heijun Jeong 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(5), 1175; https://doi.org/10.3390/s17051175 - 21 May 2017

Cited by 25 | Viewed by 6190

Abstract

A stretchable electromagnetic absorber fabricated using screen printing technology is proposed in this paper. We used a polydimethylsiloxane (PDMS) substrate to fabricate the stretchable absorber since PDMS exhibits good dielectric properties, flexibility, and restoring capabilities. DuPont PE872 (DuPont, Wilmington, CT, USA), a stretchable [...] Read more.

A stretchable electromagnetic absorber fabricated using screen printing technology is proposed in this paper. We used a polydimethylsiloxane (PDMS) substrate to fabricate the stretchable absorber since PDMS exhibits good dielectric properties, flexibility, and restoring capabilities. DuPont PE872 (DuPont, Wilmington, CT, USA), a stretchable silver conductive ink, was used for the screen printing technique. The reflection coefficient of the absorber was measured using a vector network analyzer and a waveguide. The proposed absorber was designed as a rectangular patch unit cell, wherein the top of the unit cell acted as the patch and the bottom formed the ground. The size of the patch was 8 mm × 7 mm. The prototype of the absorber consisted of two unit cells such that it fits into the WR-90 waveguide (dimensions: 22.86 mm × 10.16 mm) for experimental measurement. Before stretching the absorber, the resonant frequency was 11 GHz. When stretched along the x-direction, the resonant frequency shifted by 0.1 GHz, from 11 to 10.9 GHz, demonstrating 99% absorption. Furthermore, when stretched along the y-direction, the resonant frequency shifted by 0.6 GHz, from 11 to 10.4 GHz, demonstrating 99% absorption. Full article

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13 pages, 8267 KiB

Open AccessArticle

A Cuffless Blood Pressure Measurement Based on the Impedance Plethysmography Technique

by Shing-Hong Liu¹, Da-Chuan Cheng^2,* and Chun-Hung Su^3,*

¹ Department of Computer Science and Information Engineering, Chaoyang University of Technology, Taichung 41349, Taiwan

² Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung 40402, Taiwan

³ Institute of Medicine, School of Medicine, Chung-Shan Medical University; Department of Internal Medicine, Chung-Shan Medical University Hospital, Taichung 40201, Taiwan

Sensors 2017, 17(5), 1176; https://doi.org/10.3390/s17051176 - 21 May 2017

Cited by 46 | Viewed by 11282

Abstract

In the last decade, cuffless blood pressure measurement technology has been widely studied because it could be applied to a wearable apparatus. Electrocardiography (ECG), photo-plethysmography (PPG), and phonocardiography are always used to detect the pulse transit time (PTT) because the changed tendencies of [...] Read more.

In the last decade, cuffless blood pressure measurement technology has been widely studied because it could be applied to a wearable apparatus. Electrocardiography (ECG), photo-plethysmography (PPG), and phonocardiography are always used to detect the pulse transit time (PTT) because the changed tendencies of the PTT and blood pressure have a negative relationship. In this study, the PPG signal was replaced by the impedance plethysmography (IPG) signal and was used to detect the PTT. The placement and direction of the electrode array for the IPG measurement were discussed. Then, we designed an IPG ring that could measure an accurate IPG signal. Twenty healthy subjects participated in this study. The changes in blood pressure after exercise were evaluated through the changes of the PTT. The results showed that the change of the systolic pressure had a better relationship with the change of the PTT_IPG than that of the PTT_PPG (r = 0.700 vs. r = 0.450). Moreover, the IPG ring with spot electrodes would be more suitable to develop with the wearable cuffless blood pressure monitor than the PPG sensor. Full article

(This article belongs to the Special Issue Wearable and Ambient Sensors for Healthcare and Wellness Applications)

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15 pages, 6198 KiB

Open AccessArticle

Improving Video Segmentation by Fusing Depth Cues and the Visual Background Extractor (ViBe) Algorithm

by Xiaoqin Zhou^1,2,3

, Xiaofeng Liu^2,3,4,*, Aimin Jiang^2,3,4, Bin Yan⁵ and Chenguang Yang⁶

¹ College of Computer and Information Engineering, Hohai University, Nanjing 211100, China

² Changzhou Key Laboratory of Robotics and Intelligent Technology, Changzhou 213022, China

³ Jiangsu Key Laboratory of Special Robots, Hohai University, Changzhou 213022, China

⁴ College of IoT Engineering, Hohai University, Changzhou 213022, China

⁵ College of Electronics, Communication and Physics, Shandong University of Science and Technology, Qingdao 266590, China

⁶ Zienkiewicz Centre for Computational Engineering, Swansea University, Swansea SA1 8EN, UK

Sensors 2017, 17(5), 1177; https://doi.org/10.3390/s17051177 - 21 May 2017

Cited by 28 | Viewed by 7603

Abstract

Depth-sensing technology has led to broad applications of inexpensive depth cameras that can capture human motion and scenes in three-dimensional space. Background subtraction algorithms can be improved by fusing color and depth cues, thereby allowing many issues encountered in classical color segmentation to [...] Read more.

Depth-sensing technology has led to broad applications of inexpensive depth cameras that can capture human motion and scenes in three-dimensional space. Background subtraction algorithms can be improved by fusing color and depth cues, thereby allowing many issues encountered in classical color segmentation to be solved. In this paper, we propose a new fusion method that combines depth and color information for foreground segmentation based on an advanced color-based algorithm. First, a background model and a depth model are developed. Then, based on these models, we propose a new updating strategy that can eliminate ghosting and black shadows almost completely. Extensive experiments have been performed to compare the proposed algorithm with other, conventional RGB-D (Red-Green-Blue and Depth) algorithms. The experimental results suggest that our method extracts foregrounds with higher effectiveness and efficiency. Full article

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

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18 pages, 12722 KiB

Open AccessArticle

Impact Damage Localisation with Piezoelectric Sensors under Operational and Environmental Conditions

by Mohammad Saleh Salmanpour^*, Zahra Sharif Khodaei and M. H. Ferri Aliabadi

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

Sensors 2017, 17(5), 1178; https://doi.org/10.3390/s17051178 - 22 May 2017

Cited by 69 | Viewed by 7753

Abstract

Guided-wave structural health monitoring (SHM) systems with piezoelectric sensors are investigated for localisation of barely visible impact damage in CFRP plates under vibration and different thermal conditions. A single baseline set is used in a delay-and-sum algorithm with temperature correction for damage localisation [...] Read more.

Guided-wave structural health monitoring (SHM) systems with piezoelectric sensors are investigated for localisation of barely visible impact damage in CFRP plates under vibration and different thermal conditions. A single baseline set is used in a delay-and-sum algorithm with temperature correction for damage localisation in a large temperature range. Damage localisation is also demonstrated under transient thermal conditions, with signals recorded while the temperature is rapidly decreased. Damage severity due to successive impact events is studied under constant temperature. Damage is also localised when the plate is subjected to random vibration. Full article

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

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26 pages, 2530 KiB

Open AccessArticle

A Family of ACO Routing Protocols for Mobile Ad Hoc Networks

by Delfín Rupérez Cañas^1,†, Ana Lucila Sandoval Orozco^1,†, Luis Javier García Villalba^1,*,†

and Tai-hoon Kim^2,†

¹ Group of Analysis, Security and Systems (GASS), Department of Software Engineering and Artificial Intelligence (DISIA), Faculty of Computer Science and Engineering, Office 431, Universidad Complutense de Madrid (UCM), Calle Profesor José García Santesmases, 9, Ciudad Universitaria, 28040 Madrid, Spain

² Department of Convergence Security, Sungshin Women’s University, 249-1 Dongseon-dong 3-ga, Seoul 136-742, Korea

^† These authors contributed equally to this work.

Sensors 2017, 17(5), 1179; https://doi.org/10.3390/s17051179 - 22 May 2017

Cited by 6 | Viewed by 5494

Abstract

In this work, an ACO routing protocol for mobile ad hoc networks based on AntHocNet is specified. As its predecessor, this new protocol, called AntOR, is hybrid in the sense that it contains elements from both reactive and proactive routing. Specifically, it combines [...] Read more.

In this work, an ACO routing protocol for mobile ad hoc networks based on AntHocNet is specified. As its predecessor, this new protocol, called AntOR, is hybrid in the sense that it contains elements from both reactive and proactive routing. Specifically, it combines a reactive route setup process with a proactive route maintenance and improvement process. Key aspects of the AntOR protocol are the disjoint-link and disjoint-node routes, separation between the regular pheromone and the virtual pheromone in the diffusion process and the exploration of routes, taking into consideration the number of hops in the best routes. In this work, a family of ACO routing protocols based on AntOR is also specified. These protocols are based on protocol successive refinements. In this work, we also present a parallelized version of AntOR that we call PAntOR. Using programming multiprocessor architectures based on the shared memory protocol, PAntOR allows running tasks in parallel using threads. This parallelization is applicable in the route setup phase, route local repair process and link failure notification. In addition, a variant of PAntOR that consists of having more than one interface, which we call PAntOR-MI (PAntOR-Multiple Interface), is specified. This approach parallelizes the sending of broadcast messages by interface through threads. Full article

(This article belongs to the Special Issue Models, Systems and Applications for Sensors in Cyber Physical Systems)

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33 pages, 3003 KiB

Open AccessArticle

Impact Analysis of Flow Shaping in Ethernet-AVB/TSN and AFDX from Network Calculus and Simulation Perspective

by Feng He^*, Lin Zhao and Ershuai Li

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

Sensors 2017, 17(5), 1181; https://doi.org/10.3390/s17051181 - 22 May 2017

Cited by 40 | Viewed by 9273

Abstract

Ethernet-AVB/TSN (Audio Video Bridging/Time-Sensitive Networking) and AFDX (Avionics Full DupleX switched Ethernet) are switched Ethernet technologies, which are both candidates for real-time communication in the context of transportation systems. AFDX implements a fixed priority scheduling strategy with two priority levels. Ethernet-AVB/TSN supports a [...] Read more.

Ethernet-AVB/TSN (Audio Video Bridging/Time-Sensitive Networking) and AFDX (Avionics Full DupleX switched Ethernet) are switched Ethernet technologies, which are both candidates for real-time communication in the context of transportation systems. AFDX implements a fixed priority scheduling strategy with two priority levels. Ethernet-AVB/TSN supports a similar fixed priority scheduling with an additional Credit-Based Shaper (CBS) mechanism. Besides, TSN can support time-triggered scheduling strategy. One direct effect of CBS mechanism is to increase the delay of its flows while decreasing the delay of other priority ones. The former effect can be seen as the shaping restriction and the latter effect can be seen as the shaping benefit from CBS. The goal of this paper is to investigate the impact of CBS on different priority flows, especially on the intermediate priority ones, as well as the effect of CBS bandwidth allocation. It is based on a performance comparison of AVB/TSN and AFDX by simulation in an automotive case study. Furthermore, the shaping benefit is modeled based on integral operation from network calculus perspective. Combing with the analysis of shaping restriction and shaping benefit, some configuration suggestions on the setting of CBS bandwidth are given. Results show that the effect of CBS depends on flow loads and CBS configurations. A larger load of high priority flows in AVB tends to a better performance for the intermediate priority flows when compared with AFDX. Shaping benefit can be explained and calculated according to the changing from the permitted maximum burst. Full article

(This article belongs to the Special Issue Vehicular Sensor Networks: Technical Challenges, Supports, and Application Experiences)

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10 pages, 2930 KiB

Open AccessArticle

Hybrid-Aware Model for Senior Wellness Service in Smart Home

by Yuchae Jung

Sookmyung Women’s University, Seoul 04310, Korea

Sensors 2017, 17(5), 1182; https://doi.org/10.3390/s17051182 - 22 May 2017

Cited by 28 | Viewed by 9487

Abstract

Smart home technology with situation-awareness is important for seniors to improve safety and security. With the development of context-aware computing, wearable sensor technology, and ubiquitous computing, it is easier for seniors to manage their health problem in smart home environment. For monitoring senior [...] Read more.

Smart home technology with situation-awareness is important for seniors to improve safety and security. With the development of context-aware computing, wearable sensor technology, and ubiquitous computing, it is easier for seniors to manage their health problem in smart home environment. For monitoring senior activity in smart home, wearable, and motion sensors—such as respiration rate (RR), electrocardiography (ECG), body temperature, and blood pressure (BP)—were used for monitoring movements of seniors. For context-awareness, environmental sensors—such as gas, fire, smoke, dust, temperature, and light sensors—were used for senior location data collection. Based on senior activity, senior health status can be classified into positive and negative. Based on senior location and time, senior safety is classified into safe and emergency. In this paper, we propose a hybrid inspection service middleware for monitoring elderly health risk based on senior activity and location. This hybrid-aware model for the detection of abnormal status of seniors has four steps as follows: (1) data collection from biosensors and environmental sensors; (2) monitoring senior location and time of stay in each location using environmental sensors; (3) monitoring senior activity using biometric data; finally, (4) expectation-maximization based decision-making step recommending proper treatment based on a senior health risk ratio. Full article

(This article belongs to the Special Issue Sensors for Biomedical, Environmental and Food Monitoring Applications)

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20 pages, 4950 KiB

Open AccessArticle

Pseudorange Measurement Method Based on AIS Signals

by Jingbo Zhang^1,*

, Shufang Zhang¹ and Jinpeng Wang²

¹ Information Science and Technology College, Dalian Maritime University, Dalian 116026, China

² School of Information Science and Engineering, Dalian Polytechnic University, Dalian 116034, China

Sensors 2017, 17(5), 1183; https://doi.org/10.3390/s17051183 - 22 May 2017

Cited by 20 | Viewed by 6990

Abstract

In order to use the existing automatic identification system (AIS) to provide additional navigation and positioning services, a complete pseudorange measurements solution is presented in this paper. Through the mathematical analysis of the AIS signal, the bit-0-phases in the digital sequences were determined [...] Read more.

In order to use the existing automatic identification system (AIS) to provide additional navigation and positioning services, a complete pseudorange measurements solution is presented in this paper. Through the mathematical analysis of the AIS signal, the bit-0-phases in the digital sequences were determined as the timestamps. Monte Carlo simulation was carried out to compare the accuracy of the zero-crossing and differential peak, which are two timestamp detection methods in the additive white Gaussian noise (AWGN) channel. Considering the low-speed and low-dynamic motion characteristics of ships, an optimal estimation method based on the minimum mean square error is proposed to improve detection accuracy. Furthermore, the α difference filter algorithm was used to achieve the fusion of the optimal estimation results of the two detection methods. The results show that the algorithm can greatly improve the accuracy of pseudorange estimation under low signal-to-noise ratio (SNR) conditions. In order to verify the effectiveness of the scheme, prototypes containing the measurement scheme were developed and field tests in Xinghai Bay of Dalian (China) were performed. The test results show that the pseudorange measurement accuracy was better than 28 m (σ) without any modification of the existing AIS system. Full article

(This article belongs to the Section Remote Sensors)

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Review

Jump to: Research, Other

16 pages, 8062 KiB

Open AccessReview

Molecular Diode Studies Based on a Highly Sensitive Molecular Measurement Technique

by Madoka Iwane, Shintaro Fujii^*

and Manabu Kiguchi^*

Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan

Sensors 2017, 17(5), 956; https://doi.org/10.3390/s17050956 - 26 Apr 2017

Cited by 15 | Viewed by 7786

Abstract

In 1974, molecular electronics pioneers Mark Ratner and Arieh Aviram predicted that a single molecule could act as a diode, in which electronic current can be rectified. The electronic rectification property of the diode is one of basic functions of electronic components and [...] Read more.

In 1974, molecular electronics pioneers Mark Ratner and Arieh Aviram predicted that a single molecule could act as a diode, in which electronic current can be rectified. The electronic rectification property of the diode is one of basic functions of electronic components and since then, the molecular diode has been investigated as a first single-molecule device that would have a practical application. In this review, we first describe the experimental fabrication and electronic characterization techniques of molecular diodes consisting of a small number of molecules or a single molecule. Then, two main mechanisms of the rectification property of the molecular diode are discussed. Finally, representative results for the molecular diode are reviewed and a brief outlook on crucial issues that need to be addressed in future research is discussed. Full article

(This article belongs to the Special Issue Single-Molecule Sensing)

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30 pages, 4665 KiB

Open AccessReview

Multiplexed Electrochemical Immunosensors for Clinical Biomarkers

by Paloma Yáñez-Sedeño^*, Susana Campuzano

and José M. Pingarrón

Departamento de Química Analítica, Facultad de CC. Químicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain

Sensors 2017, 17(5), 965; https://doi.org/10.3390/s17050965 - 27 Apr 2017

Cited by 55 | Viewed by 9077

Abstract

Management and prognosis of disease requires the accurate determination of specific biomarkers indicative of normal or disease-related biological processes or responses to therapy. Moreover since multiple determinations of biomarkers have demonstrated to provide more accurate information than individual determinations to assist the clinician [...] Read more.

Management and prognosis of disease requires the accurate determination of specific biomarkers indicative of normal or disease-related biological processes or responses to therapy. Moreover since multiple determinations of biomarkers have demonstrated to provide more accurate information than individual determinations to assist the clinician in prognosis and diagnosis, the detection of several clinical biomarkers by using the same analytical device hold enormous potential for early detection and personalized therapy and will simplify the diagnosis providing more information in less time. In this field, electrochemical immunosensors have demonstrated to offer interesting alternatives against conventional strategies due to their simplicity, fast response, low cost, high sensitivity and compatibility with multiplexed determination, microfabrication technology and decentralized determinations, features which made them very attractive for integration in point-of-care (POC) devices. Therefore, in this review, the relevance and current challenges of multiplexed determination of clinical biomarkers are briefly introduced, and an overview of the electrochemical immunosensing platforms developed so far for this purpose is given in order to demonstrate the great potential of these methodologies. After highlighting the main features of the selected examples, the unsolved challenges and future directions in this field are also briefly discussed. Full article

(This article belongs to the Special Issue Electrochemical Immunosensors)

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25 pages, 13636 KiB

Open AccessReview

Metal Oxide Nanowire Preparation and Their Integration into Chemical Sensing Devices at the SENSOR Lab in Brescia

by Angela Bertuna, Guido Faglia, Matteo Ferroni, Navpreet Kaur, Hashitha M. M. Munasinghe Arachchige, Giorgio Sberveglieri and Elisabetta Comini^*

SENSOR Lab, Dipartimento di Ingegneria dell’Informazione, Università degli Studi di Brescia, via Valotti 9, 25133 Brescia, Italy

Sensors 2017, 17(5), 1000; https://doi.org/10.3390/s17051000 - 1 May 2017

Cited by 21 | Viewed by 7860

Abstract

Metal oxide 1D nanowires are probably the most promising structures to develop cheap stable and selective chemical sensors. The purpose of this contribution is to review almost two-decades of research activity at the Sensor Lab Brescia on their preparation during by vapor solid [...] Read more.

Metal oxide 1D nanowires are probably the most promising structures to develop cheap stable and selective chemical sensors. The purpose of this contribution is to review almost two-decades of research activity at the Sensor Lab Brescia on their preparation during by vapor solid (n-type In₂O₃, ZnO), vapor liquid solid (n-type SnO₂and p-type NiO) and thermal evaporation and oxidation (n-type ZnO, WO₃ and p-type CuO) methods. For each material we’ve assessed the chemical sensing performance in relation to the preparation conditions and established a rank in the detection of environmental and industrial pollutants: SnO₂ nanowires were effective in DMMP detection, ZnO nanowires in NO₂, acetone and ethanol detection, WO₃ for ammonia and CuO for ozone. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technologies in Italy 2016)

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10 pages, 4786 KiB

Open AccessReview

Screening Genotoxicity Chemistry with Microfluidic Electrochemiluminescent Arrays

by Itti Bist¹, Kiran Bano¹ and James F. Rusling^1,2,3,4,*

¹ Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA

² Department of Surgery and Neag Cancer Center, University of Connecticut Health Center, Farmington, CT 06032, USA

³ Institute of Material Science, University of Connecticut, Storrs, CT 06269, USA

⁴ School of Chemistry, National University of Ireland at Galway, Galway, Ireland

Sensors 2017, 17(5), 1008; https://doi.org/10.3390/s17051008 - 3 May 2017

Cited by 10 | Viewed by 5296

Abstract

This review describes progress in the development of electrochemiluminescent (ECL) arrays aimed at sensing DNA damage to identify genotoxic chemistry related to reactive metabolites. Genotoxicity refers to chemical or photochemical processes that damage DNA with toxic consequences. Our arrays feature DNA/enzyme films that [...] Read more.

This review describes progress in the development of electrochemiluminescent (ECL) arrays aimed at sensing DNA damage to identify genotoxic chemistry related to reactive metabolites. Genotoxicity refers to chemical or photochemical processes that damage DNA with toxic consequences. Our arrays feature DNA/enzyme films that form reactive metabolites of test chemicals that can subsequently react with DNA, thus enabling prediction of genotoxic chemical reactions. These high-throughput ECL arrays incorporating representative cohorts of human metabolic enzymes provide a platform for determining chemical toxicity profiles of new drug and environmental chemical candidates. The arrays can be designed to identify enzymes and enzyme cascades that produce the reactive metabolites. We also describe ECL arrays that detect oxidative DNA damage caused by metabolite-mediated reactive oxygen species. These approaches provide valuable high-throughput tools to complement modern toxicity bioassays and provide a more complete toxicity prediction for drug and chemical product development. Full article

(This article belongs to the Special Issue Genosensing)

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16 pages, 2280 KiB

Open AccessReview

Synergetic Effects of Combined Nanomaterials for Biosensing Applications

by Michael Holzinger^*, Alan Le Goff and Serge Cosnier

Department of Molecular Chemistry (DCM) UMR 5250, University Grenoble Alpes—CNRS, F-38000 Grenoble, France

Sensors 2017, 17(5), 1010; https://doi.org/10.3390/s17051010 - 3 May 2017

Cited by 53 | Viewed by 6544

Abstract

Nanomaterials have become essential components for the development of biosensors since such nanosized compounds were shown to clearly increase the analytical performance. The improvements are mainly related to an increased surface area, thus providing an enhanced accessibility for the analyte, the compound to [...] Read more.

Nanomaterials have become essential components for the development of biosensors since such nanosized compounds were shown to clearly increase the analytical performance. The improvements are mainly related to an increased surface area, thus providing an enhanced accessibility for the analyte, the compound to be detected, to the receptor unit, the sensing element. Nanomaterials can also add value to biosensor devices due to their intrinsic physical or chemical properties and can even act as transducers for the signal capture. Among the vast amount of examples where nanomaterials demonstrate their superiority to bulk materials, the combination of different nano-objects with different characteristics can create phenomena which contribute to new or improved signal capture setups. These phenomena and their utility in biosensor devices are summarized in a non-exhaustive way where the principles behind these synergetic effects are emphasized. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in France 2016)

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32 pages, 543 KiB

Open AccessReview

Software Defined Networking for Improved Wireless Sensor Network Management: A Survey

by Musa Ndiaye^1,*, Gerhard P. Hancke^1,2 and Adnan M. Abu-Mahfouz³

¹ Department of Electrical, Electronic and Computer Engineering, University of Pretoria, Pretoria 0028, South Africa

² Department of Computer Science, City University of Hong Kong, Hong Kong, China

³ CSIR Meraka Institute, Pretoria 0184, South Africa

Sensors 2017, 17(5), 1031; https://doi.org/10.3390/s17051031 - 4 May 2017

Cited by 185 | Viewed by 19431

Abstract

Wireless sensor networks (WSNs) are becoming increasingly popular with the advent of the Internet of things (IoT). Various real-world applications of WSNs such as in smart grids, smart farming and smart health would require a potential deployment of thousands or maybe hundreds of [...] Read more.

Wireless sensor networks (WSNs) are becoming increasingly popular with the advent of the Internet of things (IoT). Various real-world applications of WSNs such as in smart grids, smart farming and smart health would require a potential deployment of thousands or maybe hundreds of thousands of sensor nodes/actuators. To ensure proper working order and network efficiency of such a network of sensor nodes, an effective WSN management system has to be integrated. However, the inherent challenges of WSNs such as sensor/actuator heterogeneity, application dependency and resource constraints have led to challenges in implementing effective traditional WSN management. This difficulty in management increases as the WSN becomes larger. Software Defined Networking (SDN) provides a promising solution in flexible management WSNs by allowing the separation of the control logic from the sensor nodes/actuators. The advantage with this SDN-based management in WSNs is that it enables centralized control of the entire WSN making it simpler to deploy network-wide management protocols and applications on demand. This paper highlights some of the recent work on traditional WSN management in brief and reviews SDN-based management techniques for WSNs in greater detail while drawing attention to the advantages that SDN brings to traditional WSN management. This paper also investigates open research challenges in coming up with mechanisms for flexible and easier SDN-based WSN configuration and management. Full article

(This article belongs to the Collection Smart Industrial Wireless Sensor Networks)

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24 pages, 7282 KiB

Open AccessReview

Nanomaterials for Electrochemical Immunosensing

by Mingfei Pan, Ying Gu, Yaguang Yun, Min Li, Xincui Jin and Shuo Wang^*

Key Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technolo, Tianjin 300457, China

Sensors 2017, 17(5), 1041; https://doi.org/10.3390/s17051041 - 5 May 2017

Cited by 55 | Viewed by 10602

Abstract

Electrochemical immunosensors resulting from a combination of the traditional immunoassay approach with modern biosensors and electrochemical analysis constitute a current research hotspot. They exhibit both the high selectivity characteristics of immunoassays and the high sensitivity of electrochemical analysis, along with other merits such [...] Read more.

Electrochemical immunosensors resulting from a combination of the traditional immunoassay approach with modern biosensors and electrochemical analysis constitute a current research hotspot. They exhibit both the high selectivity characteristics of immunoassays and the high sensitivity of electrochemical analysis, along with other merits such as small volume, convenience, low cost, simple preparation, and real-time on-line detection, and have been widely used in the fields of environmental monitoring, medical clinical trials and food analysis. Notably, the rapid development of nanotechnology and the wide application of nanomaterials have provided new opportunities for the development of high-performance electrochemical immunosensors. Various nanomaterials with different properties can effectively solve issues such as the immobilization of biological recognition molecules, enrichment and concentration of trace analytes, and signal detection and amplification to further enhance the stability and sensitivity of the electrochemical immunoassay procedure. This review introduces the working principles and development of electrochemical immunosensors based on different signals, along with new achievements and progress related to electrochemical immunosensors in various fields. The importance of various types of nanomaterials for improving the performance of electrochemical immunosensor is also reviewed to provide a theoretical basis and guidance for the further development and application of nanomaterials in electrochemical immunosensors. Full article

(This article belongs to the Special Issue Electrochemical Immunosensors)

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21 pages, 4692 KiB

Open AccessReview

New Frontiers for Applications of Thermal Infrared Imaging Devices: Computational Psychopshysiology in the Neurosciences

by Daniela Cardone^*

and Arcangelo Merla

Infrared Imaging Lab, ITAB Institute for Advanced Biomedical Technologies, Department of Neuroscience, Imaging and Clinical Sciences, University of Chieti-Pescara, Chieti 66100, Italy

Sensors 2017, 17(5), 1042; https://doi.org/10.3390/s17051042 - 5 May 2017

Cited by 84 | Viewed by 12465

Abstract

Thermal infrared imaging has been proposed, and is now used, as a tool for the non-contact and non-invasive computational assessment of human autonomic nervous activity and psychophysiological states. Thanks to a new generation of high sensitivity infrared thermal detectors and the development of [...] Read more.

Thermal infrared imaging has been proposed, and is now used, as a tool for the non-contact and non-invasive computational assessment of human autonomic nervous activity and psychophysiological states. Thanks to a new generation of high sensitivity infrared thermal detectors and the development of computational models of the autonomic control of the facial cutaneous temperature, several autonomic variables can be computed through thermal infrared imaging, including localized blood perfusion rate, cardiac pulse rate, breath rate, sudomotor and stress responses. In fact, all of these parameters impact on the control of the cutaneous temperature. The physiological information obtained through this approach, could then be used to infer about a variety of psychophysiological or emotional states, as proved by the increasing number of psychophysiology or neurosciences studies that use thermal infrared imaging. This paper presents a review of the principal achievements of thermal infrared imaging in computational psychophysiology, focusing on the capability of the technique for providing ubiquitous and unwired monitoring of psychophysiological activity and affective states. It also presents a summary on the modern, up-to-date infrared sensors technology. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technologies in Italy 2016)

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12 pages, 4369 KiB

Open AccessReview

A Versatile Electronic Tongue Based on Surface Plasmon Resonance Imaging and Cross-Reactive Sensor Arrays—A Mini-Review

by Laurie-Amandine Garçon^1,2,3,4, Maria Genua^1,2,3, Yanjie Hou^1,2,3, Arnaud Buhot^1,2,3

, Roberto Calemczuk^1,2,3, Thierry Livache^1,2,3, Martial Billon^1,2,3, Christine Le Narvor⁵, David Bonnaffé⁵, Hugues Lortat-Jacob^6,7,8 and Yanxia Hou^1,2,3,*

¹ Institut Nanosciences et Cryogénie, University of Grenoble Alpes, INAC-SyMMES, F-38000 Grenoble, France

² Centre National de la Recherche Scientifique, SyMMES UMR 5819, F-38000 Grenoble, France

³ Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), INAC-SyMMES, F-38000 Grenoble, France

⁴ Institut Néel, F-38000 Grenoble, France

⁵ ICMMO/G2M/LCOM, UMR 8182 (CNRS-UPS), LabEx LERMIT, Université Paris-Sud 11, 91405 Orsay CEDEX, France

⁶ Institut de Biologie Structurale, University of Grenoble Alpes, UMR 5075, 38027 Grenoble, France

⁷ Centre National de la Recherche Scientifique, Institut de Biologie Structurale, UMR 5075, 38027 Grenoble, France

⁸ Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Institut de Biologie Structurale, UMR 5075, 38027 Grenoble, France

Sensors 2017, 17(5), 1046; https://doi.org/10.3390/s17051046 - 6 May 2017

Cited by 16 | Viewed by 6526

Abstract

Nowadays, there is a strong demand for the development of new analytical devices with novel performances to improve the quality of our daily lives. In this context, multisensor systems such as electronic tongues (eTs) have emerged as promising alternatives. Recently, we have developed [...] Read more.

Nowadays, there is a strong demand for the development of new analytical devices with novel performances to improve the quality of our daily lives. In this context, multisensor systems such as electronic tongues (eTs) have emerged as promising alternatives. Recently, we have developed a new versatile eT system by coupling surface plasmon resonance imaging (SPRi) with cross-reactive sensor arrays. In order to largely simplify the preparation of sensing materials with a great diversity, an innovative combinatorial approach was proposed by combining and mixing a small number of easily accessible molecules displaying different physicochemical properties. The obtained eT was able to generate 2D continuous evolution profile (CEP) and 3D continuous evolution landscape (CEL), which is also called 3D image, with valuable kinetic information, for the discrimination and classification of samples. Here, diverse applications of such a versatile eT have been summarized. It is not only effective for pure protein analysis, capable of differentiating protein isoforms such as chemokines CXCL12α and CXCL12γ, but can also be generalized for the analysis of complex mixtures, such as milk samples, with promising potential for monitoring the deterioration of milk. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in France 2016)

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21 pages, 832 KiB

Open AccessReview

Identification of Chinese Herbal Medicines with Electronic Nose Technology: Applications and Challenges

by Huaying Zhou^1,2, Dehan Luo^1,*, Hamid GholamHosseini³

, Zhong Li⁴ and Jiafeng He¹

¹ School of Information Engineering, Guangdong University of Technology, Guangzhou 510006, China

² College of Medical Information Engineering, Guangdong Pharmaceutical University, Guangzhou 510006, China

³ School of Engineering, Computer and Mathematical Sciences, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand

⁴ College of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou 510006, China

Sensors 2017, 17(5), 1073; https://doi.org/10.3390/s17051073 - 9 May 2017

Cited by 59 | Viewed by 9340

Abstract

This paper provides a review of the most recent works in machine olfaction as applied to the identification of Chinese Herbal Medicines (CHMs). Due to the wide variety of CHMs, the complexity of growing sources and the diverse specifications of herb components, the [...] Read more.

This paper provides a review of the most recent works in machine olfaction as applied to the identification of Chinese Herbal Medicines (CHMs). Due to the wide variety of CHMs, the complexity of growing sources and the diverse specifications of herb components, the quality control of CHMs is a challenging issue. Much research has demonstrated that an electronic nose (E-nose) as an advanced machine olfaction system, can overcome this challenge through identification of the complex odors of CHMs. E-nose technology, with better usability, high sensitivity, real-time detection and non-destructive features has shown better performance in comparison with other analytical techniques such as gas chromatography-mass spectrometry (GC-MS). Although there has been immense development of E-nose techniques in other applications, there are limited reports on the application of E-noses for the quality control of CHMs. The aim of current study is to review practical implementation and advantages of E-noses for robust and effective odor identification of CHMs. It covers the use of E-nose technology to study the effects of growing regions, identification methods, production procedures and storage time on CHMs. Moreover, the challenges and applications of E-nose for CHM identification are investigated. Based on the advancement in E-nose technology, odor may become a new quantitative index for quality control of CHMs and drug discovery. It was also found that more research could be done in the area of odor standardization and odor reproduction for remote sensing. Full article

(This article belongs to the Special Issue Materials and Applications for Sensors and Transducers)

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35 pages, 7858 KiB

Open AccessReview

Development of Conductivity Sensors for Multi-Phase Flow Local Measurements at the Polytechnic University of Valencia (UPV) and University Jaume I of Castellon (UJI)

by José Luis Muñoz-Cobo^1,*

, Sergio Chiva², Santos Méndez³, Guillem Monrós²

, Alberto Escrivá¹

and José Luis Cuadros¹

¹ Instituto de Ingeniería Energética, Universitat Politècnica de València, 46022 Valencia, Spain

² Unidad de Mecánica de Fluidos, Universitat Jaume I, 12071 Castellón, Spain

³ Faculty of Electric and Mechanical Engineering, Universidad Autónoma de Nueva León, Monterrey 66451, Mexico

Sensors 2017, 17(5), 1077; https://doi.org/10.3390/s17051077 - 10 May 2017

Cited by 22 | Viewed by 7906

Abstract

This paper describes all the procedures and methods currently used at UPV (Universitat Politécnica de Valencia) and UJI (University Jaume I) for the development and use of sensors for multi-phase flow analysis in vertical pipes. This paper also describes the methods that we [...] Read more.

This paper describes all the procedures and methods currently used at UPV (Universitat Politécnica de Valencia) and UJI (University Jaume I) for the development and use of sensors for multi-phase flow analysis in vertical pipes. This paper also describes the methods that we use to obtain the values of the two-phase flow magnitudes from the sensor signals and the validation and cross-verification methods developed to check the consistency of the results obtained for these magnitudes with the sensors. First, we provide information about the procedures used to build the multi-sensor conductivity probes and some of the tests performed with different materials to avoid sensor degradation issues. In addition, we provide information about the characteristics of the electric circuits that feed the sensors. Then the data acquisition of the conductivity probe, the signal conditioning and the data processing including the device that have been designed to automatize all the measurement process of moving the sensors inside the channels by means of stepper electric motors controlled by computer are shown in operation. Then, we explain the methods used for bubble identification and categorization. Finally, we describe the methodology used to obtain the two-phase flow information from the sensor signals. This includes the following items: void fraction, gas velocity, Sauter mean diameter and interfacial area concentration. The last part of this paper is devoted to the conductance probes developed for the annular flow analysis, which includes the analysis of the interfacial waves produced in annular flow and that requires a different type of sensor. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Spain 2016)

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25 pages, 5530 KiB

Open AccessReview

Nitride-Based Materials for Flexible MEMS Tactile and Flow Sensors in Robotics

by Claudio Abels^1,2,3,†, Vincenzo Mariano Mastronardi^1,†, Francesco Guido¹, Tommaso Dattoma¹, Antonio Qualtieri¹

, William M. Megill³, Massimo De Vittorio^1,2,* and Francesco Rizzi^1,*

¹ Center for Biomolecular Nanotechnologies @UNILE, Istituto Italiano di Tecnologia (IIT), Arnesano (LE) 73010, Italy

² Dipartimento di Ingegneria dell’Innovazione, Università del Salento, Lecce 73100, Italy

³ Faculty of Technology and Bionics, Rhine-Waal University of Applied Sciences Kleve 47533, Germany

^† These authors contributed equally to this work.

Sensors 2017, 17(5), 1080; https://doi.org/10.3390/s17051080 - 10 May 2017

Cited by 43 | Viewed by 12221

Abstract

The response to different force load ranges and actuation at low energies is of considerable interest for applications of compliant and flexible devices undergoing large deformations. We present a review of technological platforms based on nitride materials (aluminum nitride and silicon nitride) for [...] Read more.

The response to different force load ranges and actuation at low energies is of considerable interest for applications of compliant and flexible devices undergoing large deformations. We present a review of technological platforms based on nitride materials (aluminum nitride and silicon nitride) for the microfabrication of a class of flexible micro-electro-mechanical systems. The approach exploits the material stress differences among the constituent layers of nitride-based (AlN/Mo, Si

_{x}

N

_{y}

/Si and AlN/polyimide) mechanical elements in order to create microstructures, such as upwardly-bent cantilever beams and bowed circular membranes. Piezoresistive properties of nichrome strain gauges and direct piezoelectric properties of aluminum nitride can be exploited for mechanical strain/stress detection. Applications in flow and tactile sensing for robotics are described. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technologies in Italy 2016)

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25 pages, 1743 KiB

Open AccessReview

Remote Sensing for Crop Water Management: From ET Modelling to Services for the End Users

by Alfonso Calera^1,*

, Isidro Campos¹

, Anna Osann¹, Guido D’Urso²

and Massimo Menenti^3,4

¹ GIS and Remote Sensing Group, Institute for Regional Development, University of Castilla-La Mancha, Campus Universitario SN, 02071 Albacete, Spain

² Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, 80055 Portici (NA), Italy

³ Department of Geoscience and Remote Sensing, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands

⁴ State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Science, Beijing 100101, China

Sensors 2017, 17(5), 1104; https://doi.org/10.3390/s17051104 - 11 May 2017

Cited by 201 | Viewed by 15041

Abstract

The experiences gathered during the past 30 years support the operational use of irrigation scheduling based on frequent multi-spectral image data. Currently, the operational use of dense time series of multispectral imagery at high spatial resolution makes monitoring of crop biophysical parameters feasible, [...] Read more.

The experiences gathered during the past 30 years support the operational use of irrigation scheduling based on frequent multi-spectral image data. Currently, the operational use of dense time series of multispectral imagery at high spatial resolution makes monitoring of crop biophysical parameters feasible, capturing crop water use across the growing season, with suitable temporal and spatial resolutions. These achievements, and the availability of accurate forecasting of meteorological data, allow for precise predictions of crop water requirements with unprecedented spatial resolution. This information is greatly appreciated by the end users, i.e., professional farmers or decision-makers, and can be provided in an easy-to-use manner and in near-real-time by using the improvements achieved in web-GIS methodologies (Geographic Information Systems based on web technologies). This paper reviews the most operational and explored methods based on optical remote sensing for the assessment of crop water requirements, identifying strengths and weaknesses and proposing alternatives to advance towards full operational application of this methodology. In addition, we provide a general overview of the tools, which facilitates co-creation and collaboration with stakeholders, paying special attention to these approaches based on web-GIS tools. Full article

(This article belongs to the Special Issue Earth Observation for Biodiversity and Ecosystem Services: Remote Sensing Data Handling and Analysis)

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11 pages, 2632 KiB

Open AccessReview

Metal–Organic Frameworks as Active Materials in Electronic Sensor Devices

by Michael G. Campbell^1,* and Mircea Dincă^2,*

¹ Department of Chemistry, Barnard College, 3009 Broadway, New York, NY 10027, USA

² Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA

Sensors 2017, 17(5), 1108; https://doi.org/10.3390/s17051108 - 12 May 2017

Cited by 226 | Viewed by 18974

Abstract

In the past decade, advances in electrically conductive metal–organic frameworks (MOFs) and MOF-based electronic devices have created new opportunities for the development of next-generation sensors. Here we review this rapidly-growing field, with a focus on the different types of device configurations that have [...] Read more.

In the past decade, advances in electrically conductive metal–organic frameworks (MOFs) and MOF-based electronic devices have created new opportunities for the development of next-generation sensors. Here we review this rapidly-growing field, with a focus on the different types of device configurations that have allowed for the use of MOFs as active components of electronic sensor devices. Full article

(This article belongs to the Special Issue Chemiresistive Sensors: Status and the Future)

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33 pages, 10220 KiB

Open AccessReview

A Review of Microwave Thermography Nondestructive Testing and Evaluation

by Hong Zhang^1,*

, Ruizhen Yang², Yunze He^3,*, Ali Foudazi⁴, Liang Cheng⁵ and Guiyun Tian⁵

¹ School of Electronic and Information Engineering, Fuqing Branch of Fujian Normal University, Fuzhou 350300, China

² Department of Civil and Architecture Engineering, Changsha University, Changsha 410022, China

³ College of Electrical and Information Engineering, Hunan University, Changsha 410082, China

⁴ Electrical and Computer Engineering Department, Missouri University of Science and Technology, Rolla, MO 65409, USA

⁵ School of Electrical and Electronic Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK

Sensors 2017, 17(5), 1123; https://doi.org/10.3390/s17051123 - 15 May 2017

Cited by 70 | Viewed by 15064

Abstract

Microwave thermography (MWT) has many advantages including strong penetrability, selective heating, volumetric heating, significant energy savings, uniform heating, and good thermal efficiency. MWT has received growing interest due to its potential to overcome some of the limitations of microwave nondestructive testing (NDT) and [...] Read more.

Microwave thermography (MWT) has many advantages including strong penetrability, selective heating, volumetric heating, significant energy savings, uniform heating, and good thermal efficiency. MWT has received growing interest due to its potential to overcome some of the limitations of microwave nondestructive testing (NDT) and thermal NDT. Moreover, during the last few decades MWT has attracted growing interest in materials assessment. In this paper, a comprehensive review of MWT techniques for materials evaluation is conducted based on a detailed literature survey. First, the basic principles of MWT are described. Different types of MWT, including microwave pulsed thermography, microwave step thermography, microwave pulsed phase thermography, and microwave lock-in thermography are defined and introduced. Then, MWT case studies are discussed. Next, comparisons with other thermography and NDT methods are conducted. Finally, the trends in MWT research are outlined, including new theoretical studies, simulations and modelling, signal processing algorithms, internal properties characterization, automatic separation and inspection systems. This work provides a summary of MWT, which can be utilized for material failures prevention and quality control. Full article

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

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22 pages, 11177 KiB

Open AccessReview

Multispectral, Fluorescent and Photoplethysmographic Imaging for Remote Skin Assessment

by Janis Spigulis

Biophotonics Laboratory, Institute of Atomic Physics and Spectroscopy, University of Latvia, Riga LV-1586, Latvia

Sensors 2017, 17(5), 1165; https://doi.org/10.3390/s17051165 - 19 May 2017

Cited by 28 | Viewed by 13031

Abstract

Optical tissue imaging has several advantages over the routine clinical imaging methods, including non-invasiveness (it does not change the structure of tissues), remote operation (it avoids infections) and the ability to quantify the tissue condition by means of specific image parameters. Dermatologists and [...] Read more.

Optical tissue imaging has several advantages over the routine clinical imaging methods, including non-invasiveness (it does not change the structure of tissues), remote operation (it avoids infections) and the ability to quantify the tissue condition by means of specific image parameters. Dermatologists and other skin experts need compact (preferably pocket-size), self-sustaining and easy-to-use imaging devices. The operational principles and designs of ten portable in-vivo skin imaging prototypes developed at the Biophotonics Laboratory of Institute of Atomic Physics and Spectroscopy, University of Latvia during the recent five years are presented in this paper. Four groups of imaging devices are considered. Multi-spectral imagers offer possibilities for distant mapping of specific skin parameters, thus facilitating better diagnostics of skin malformations. Autofluorescence intensity and photobleaching rate imagers show a promising potential for skin tumor identification and margin delineation. Photoplethysmography video-imagers ensure remote detection of cutaneous blood pulsations and can provide real-time information on cardiovascular parameters and anesthesia efficiency. Multimodal skin imagers perform several of the abovementioned functions by taking a number of spectral and video images with the same image sensor. Design details of the developed prototypes and results of clinical tests illustrating their functionality are presented and discussed. Full article

(This article belongs to the Special Issue Optical Methods in Sensing and Imaging for Medical and Biological Applications)

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37 pages, 9072 KiB

Open AccessReview

The Boom in 3D-Printed Sensor Technology

by Yuanyuan Xu¹, Xiaoyue Wu², Xiao Guo², Bin Kong¹, Min Zhang², Xiang Qian^2,*

, Shengli Mi^2,3,* and Wei Sun^1,2,4,5,*

¹ Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, China

² Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China

³ Open Fiesta, Tsinghua University, Shenzhen 518055, China

⁴ Department of Mechanical Engineering, Drexel University, Philadelphia 19104, PA, USA

⁵ Department of Mechanical Engineering and Mechanics, Tsinghua University, Beijing 100084, China

Sensors 2017, 17(5), 1166; https://doi.org/10.3390/s17051166 - 19 May 2017

Cited by 265 | Viewed by 36034

Abstract

Future sensing applications will include high-performance features, such as toxin detection, real-time monitoring of physiological events, advanced diagnostics, and connected feedback. However, such multi-functional sensors require advancements in sensitivity, specificity, and throughput with the simultaneous delivery of multiple detection in a short time. [...] Read more.

Future sensing applications will include high-performance features, such as toxin detection, real-time monitoring of physiological events, advanced diagnostics, and connected feedback. However, such multi-functional sensors require advancements in sensitivity, specificity, and throughput with the simultaneous delivery of multiple detection in a short time. Recent advances in 3D printing and electronics have brought us closer to sensors with multiplex advantages, and additive manufacturing approaches offer a new scope for sensor fabrication. To this end, we review the recent advances in 3D-printed cutting-edge sensors. These achievements demonstrate the successful application of 3D-printing technology in sensor fabrication, and the selected studies deeply explore the potential for creating sensors with higher performance. Further development of multi-process 3D printing is expected to expand future sensor utility and availability. Full article

(This article belongs to the Special Issue Micro and Nanofabrication Technologies for Biosensors)

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13 pages, 2128 KiB

Open AccessReview

Current and Potential Developments of Cortisol Aptasensing towards Point-of-Care Diagnostics (POTC)

by Azrul Syafiq Zainol Abidin¹, Ruslinda A. Rahim^1,*, Mohd Khairuddin Md Arshad¹, Mohd Faudzi Fatin Nabilah¹, Chun Hong Voon¹, Thean-Hock Tang² and Marimuthu Citartan²

¹ Institute of Nano Electronic Engineering (INEE), Universiti Malaysia Perlis, Kangar, Perlis 01000, Malaysia

² Advanced Medical & Dental Institute (AMDI), Universiti Sains Malaysia, Kepala Batas, Penang 13200, Malaysia

Sensors 2017, 17(5), 1180; https://doi.org/10.3390/s17051180 - 22 May 2017

Cited by 32 | Viewed by 11342

Abstract

Anxiety is a psychological problem that often emerges during the normal course of human life. The detection of anxiety often involves a physical exam and a self-reporting questionnaire. However, these approaches have limitations, as the data might lack reliability and consistency upon application [...] Read more.

Anxiety is a psychological problem that often emerges during the normal course of human life. The detection of anxiety often involves a physical exam and a self-reporting questionnaire. However, these approaches have limitations, as the data might lack reliability and consistency upon application to the same population over time. Furthermore, there might be varying understanding and interpretations of the particular question by the participant, which necessitating the approach of using biomarker-based measurement for stress diagnosis. The most prominent biomarker related to stress, hormone cortisol, plays a key role in the fight-or-flight situation, alters the immune response, and suppresses the digestive and the reproductive systems. We have taken the endeavour to review the available aptamer-based biosensor (aptasensor) for cortisol detection. The potential point-of-care diagnostic strategies that could be harnessed for the aptasensing of cortisol were also envisaged. Full article

(This article belongs to the Special Issue Aptasensors 2016)

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21 pages, 2989 KiB

Open AccessReview

Molecular Techniques for the Detection of Organisms in Aquatic Environments, with Emphasis on Harmful Algal Bloom Species

by Linda K. Medlin^1,* and Jahir Orozco²

¹ Marine Biological Association of the UK, The Citadel, Plymouth PL1 2PB, UK

² Max Planck Tandem Group in Nanobioengineering, Universidad de Antioquia, Complejo Ruta N, Calle 67, N° 52-20, Medellín 050010, Colombia

Sensors 2017, 17(5), 1184; https://doi.org/10.3390/s17051184 - 22 May 2017

Cited by 82 | Viewed by 11663

Abstract

Molecular techniques to detect organisms in aquatic ecosystems are being gradually considered as an attractive alternative to standard laboratory methods. They offer faster and more accurate means of detecting and monitoring species, with respect to their traditional homologues based on culture and microscopic [...] Read more.

Molecular techniques to detect organisms in aquatic ecosystems are being gradually considered as an attractive alternative to standard laboratory methods. They offer faster and more accurate means of detecting and monitoring species, with respect to their traditional homologues based on culture and microscopic counting. Molecular techniques are particularly attractive when multiple species need to be detected and/or are in very low abundance. This paper reviews molecular techniques based on whole cells, such as microscope-based enumeration and Fluorescence In-Situ Hybridization (FISH) and molecular cell-free formats, such as sandwich hybridization assay (SHA), biosensors, microarrays, quantitative polymerase chain reaction (qPCR) and real time PCR (RT-PCR). Those that combine one or several laboratory functions into a single integrated system (lab-on-a-chip) and techniques that generate a much higher throughput data, such as next-generation systems (NGS), were also reviewed. We also included some other approaches that enhance the performance of molecular techniques. For instance, nano-bioengineered probes and platforms, pre-concentration and magnetic separation systems, and solid-phase hybridization offer highly pre-concentration capabilities. Isothermal amplification and hybridization chain reaction (HCR) improve hybridization and amplification techniques. Finally, we presented a study case of field remote sensing of harmful algal blooms (HABs), the only example of real time monitoring, and close the discussion with future directions and concluding remarks. Full article

(This article belongs to the Special Issue Genosensing)

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1 pages, 157 KiB

Open AccessErratum

Erratum: Kim, K.-P.; Singh, A.K.; Bai, X.; Leprun, L.; Bhunia, A.K. Novel PCR Assays Complement Laser Biosensor-Based Method and Facilitate Listeria Species Detection from Food. Sensors 2015, 15, 22672–22691

by Kwang-Pyo Kim^1,2,†, Atul K. Singh^1,†

, Xingjian Bai¹, Lena Leprun^1,‡ and Arun K. Bhunia^1,3,*

¹ Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN 47907, USA

² Department of Food Science and Technology, College of Agriculture and Life Sciences, Chonbuk National University, Jeonbuk 561756, Korea

³ Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA

^† These authors contributed equally to this study.

^‡ Present address: CROUS de Dijon, Dijon CEDEX 21012, France.

Sensors 2017, 17(5), 945; https://doi.org/10.3390/s17050945 - 25 Apr 2017

Cited by 1 | Viewed by 4553

Abstract

The authors wish to correct the oligonucleotide sequence of primer E-LAP-F1 and LIS-R1 in Table 1in their paper published in Sensors [1], doi:10.3390/s150922672, https://www.mdpi.com/1424-8220/15/9/22672. The following table should be used.[...] Full article

(This article belongs to the Collection Sensors in Agriculture and Forestry)

8 pages, 922 KiB

Open AccessLetter

A Study of Applying Pulsed Remote Field Eddy Current in Ferromagnetic Pipes Testing

by Qingwang Luo^1,2

, Yibing Shi^1,2,*, Zhigang Wang², Wei Zhang^1,2 and Yanjun Li^1,2

¹ Center for Information Geoscience, University of Electronic Science and Technology of China, Chengdu 611731, China

² School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China

Sensors 2017, 17(5), 1038; https://doi.org/10.3390/s17051038 - 5 May 2017

Cited by 24 | Viewed by 5251

Abstract

Pulsed Remote Field Eddy Current Testing (PRFECT) attracts the attention in the testing of ferromagnetic pipes because of its continuous spectrum. This paper simulated the practical PRFECT of pipes by using ANSYS software and employed Least Squares Support Vector Regression (LSSVR) to extract [...] Read more.

Pulsed Remote Field Eddy Current Testing (PRFECT) attracts the attention in the testing of ferromagnetic pipes because of its continuous spectrum. This paper simulated the practical PRFECT of pipes by using ANSYS software and employed Least Squares Support Vector Regression (LSSVR) to extract the zero-crossing time to analyze the pipe thickness. As a result, a secondary peak is found in zero-crossing time when transmitter passed by a defect. The secondary peak will lead to wrong quantification and the localization of defects, especially when defects are found only at the transmitter location. Aiming to eliminate the secondary peaks, double sensing coils are set in the transition zone and Wiener deconvolution filter is applied. In the proposed method, position dependent response of the differential signals from the double sensing coils is calibrated by employing zero-mean normalization. The methods proposed in this paper are validated by analyzing the simulation signals and can improve the practicality of PRFECT of ferromagnetic pipes. Full article

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

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15 pages, 679 KiB

Open AccessTechnical Note

Dual-Polarization Observations of Slowly Varying Solar Emissions from a Mobile X-Band Radar

by Marco Gabella^*

and Andreas Leuenberger

MeteoSwiss, via ai Monti 146, Locarno-Monti CH-6605, Switzerland

Sensors 2017, 17(5), 1185; https://doi.org/10.3390/s17051185 - 22 May 2017

Cited by 8 | Viewed by 5043

Abstract

The radio noise that comes from the Sun has been reported in literature as a reference signal to check the quality of dual-polarization weather radar receivers for the S-band and C-band. In most cases, the focus was on relative calibration: horizontal and vertical [...] Read more.

The radio noise that comes from the Sun has been reported in literature as a reference signal to check the quality of dual-polarization weather radar receivers for the S-band and C-band. In most cases, the focus was on relative calibration: horizontal and vertical polarizations were evaluated versus the reference signal mainly in terms of standard deviation of the difference. This means that the investigated radar receivers were able to reproduce the slowly varying component of the microwave signal emitted by the Sun. A novel method, aimed at the absolute calibration of dual-polarization receivers, has recently been presented and applied for the C-band. This method requires the antenna beam axis to be pointed towards the center of the Sun for less than a minute. Standard deviations of the difference as low as 0.1 dB have been found for the Swiss radars. As far as the absolute calibration is concerned, the average differences were of the order of −0.6 dB (after noise subtraction). The method has been implemented on a mobile, X-band radar, and this paper presents the successful results that were obtained during the 2016 field campaign in Payerne (Switzerland). Despite a relatively poor Sun-to-Noise ratio, the “small” (~0.4 dB) amplitude of the slowly varying emission was captured and reproduced; the standard deviation of the difference between the radar and the reference was ~0.2 dB. The absolute calibration of the vertical and horizontal receivers was satisfactory. After the noise subtraction and atmospheric correction a, the mean difference was close to 0 dB. Full article

(This article belongs to the Section Remote Sensors)

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