Sensors

17 pages, 1621 KiB

Open AccessArticle

Optimisation in the Design of Environmental Sensor Networks with Robustness Consideration

by Setia Budi^1,2,*, Paulo De Souza²

, Greg Timms², Vishv Malhotra¹ and Paul Turner¹

¹ School of Engineering and ICT, University of Tasmania, Private Bag 87, Hobart, TAS 7001, Australia

² Commonwealth Scientific and Industrial Research Organisation, 15 College Road, Sandy Bay, TAS 7005, Australia

Sensors 2015, 15(12), 29765-29781; https://doi.org/10.3390/s151229765 - 27 Nov 2015

Cited by 10 | Viewed by 6024

Abstract

This work proposes the design of Environmental Sensor Networks (ESN) through balancing robustness and redundancy. An Evolutionary Algorithm (EA) is employed to find the optimal placement of sensor nodes in the Region of Interest (RoI). Data quality issues are introduced to simulate their [...] Read more.

This work proposes the design of Environmental Sensor Networks (ESN) through balancing robustness and redundancy. An Evolutionary Algorithm (EA) is employed to find the optimal placement of sensor nodes in the Region of Interest (RoI). Data quality issues are introduced to simulate their impact on the performance of the ESN. Spatial Regression Test (SRT) is also utilised to promote robustness in data quality of the designed ESN. The proposed method provides high network representativeness (fit for purpose) with minimum sensor redundancy (cost), and ensures robustness by enabling the network to continue to achieve its objectives when some sensors fail. Full article

(This article belongs to the Section Sensor Networks)

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20 pages, 3067 KiB

Open AccessArticle

Throughput Maximization for Sensor-Aided Cognitive Radio Networks with Continuous Energy Arrivals

by Thanh-Tung Nguyen^† and Insoo Koo^*,†

¹ Department of Electrical/Electronics and Computer Engineering, University of Ulsan, 93-Daehak-ro, Nam-gu, Ulsan 680-749, Korea

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 29782-29801; https://doi.org/10.3390/s151229766 - 27 Nov 2015

Cited by 4 | Viewed by 4805

Abstract

We consider a Sensor-Aided Cognitive Radio Network (SACRN) in which sensors capable of harvesting energy are distributed throughout the network to support secondary transmitters for sensing licensed channels in order to improve both energy and spectral efficiency. Harvesting ambient energy is one of [...] Read more.

We consider a Sensor-Aided Cognitive Radio Network (SACRN) in which sensors capable of harvesting energy are distributed throughout the network to support secondary transmitters for sensing licensed channels in order to improve both energy and spectral efficiency. Harvesting ambient energy is one of the most promising solutions to mitigate energy deficiency, prolong device lifetime, and partly reduce the battery size of devices. So far, many works related to SACRN have considered single secondary users capable of harvesting energy in whole slot as well as short-term throughput. In the paper, we consider two types of energy harvesting sensor nodes (EHSN): Type-I sensor nodes will harvest ambient energy in whole slot duration, whereas type-II sensor nodes will only harvest energy after carrying out spectrum sensing. In the paper, we also investigate long-term throughput in the scheduling window, and formulate the throughput maximization problem by considering energy-neutral operation conditions of type-I and -II sensors and the target detection probability. Through simulations, it is shown that the sensing energy consumption of all sensor nodes can be efficiently managed with the proposed scheme to achieve optimal long-term throughput in the window. Full article

(This article belongs to the Section Sensor Networks)

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19 pages, 1029 KiB

Open AccessArticle

UAV Control on the Basis of 3D Landmark Bearing-Only Observations

by Simon Karpenko, Ivan Konovalenko, Alexander Miller, Boris Miller^*

and Dmitry Nikolaev

Institute for Information Transmission Problems RAS, Bolshoy Karetny per. 19, Build. 1, GSP-4, Moscow 127051, Russia

Sensors 2015, 15(12), 29802-29820; https://doi.org/10.3390/s151229768 - 27 Nov 2015

Cited by 56 | Viewed by 6527

Abstract

The article presents an approach to the control of a UAV on the basis of 3D landmark observations. The novelty of the work is the usage of the 3D RANSAC algorithm developed on the basis of the landmarks’ position prediction with the aid [...] Read more.

The article presents an approach to the control of a UAV on the basis of 3D landmark observations. The novelty of the work is the usage of the 3D RANSAC algorithm developed on the basis of the landmarks’ position prediction with the aid of a modified Kalman-type filter. Modification of the filter based on the pseudo-measurements approach permits obtaining unbiased UAV position estimation with quadratic error characteristics. Modeling of UAV flight on the basis of the suggested algorithm shows good performance, even under significant external perturbations. Full article

(This article belongs to the Special Issue UAV Sensors for Environmental Monitoring)

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20 pages, 1906 KiB

Open AccessArticle

Process Mining Methodology for Health Process Tracking Using Real-Time Indoor Location Systems

by Carlos Fernandez-Llatas^1,2,*

, Aroa Lizondo¹, Eduardo Monton³, Jose-Miguel Benedi⁴ and Vicente Traver^1,2

¹ Instituto Universitario de Investigación de Aplicaciones de las Tecnologías de la Información y de las Comunicaciones Avanzadas (ITACA), Universitat Politecnica de Valencia, Camino de Vera S/N, Valencia 46022, Spain

² Unidad Mixta de Reingeniería de Procesos Sociosanitarios (eRPSS), Instituto de Investigación Sanitaria del Hospital Universitario y Politecnico La Fe, Bulevar Sur S/N, Valencia 46026, Spain

³ My Sphera S.L. Ronda Auguste y Louis Lumiere 23, Nave 13, Parque Tecnologico, Paterna 46980, Spain

⁴ Pattern Recognition and Human Language Technology (PRHTL), Universitat Politecnica de Valencia, Camino de Vera S/N, Valencia 46022, Spain

Sensors 2015, 15(12), 29821-29840; https://doi.org/10.3390/s151229769 - 30 Nov 2015

Cited by 99 | Viewed by 11067

Abstract

The definition of efficient and accurate health processes in hospitals is crucial for ensuring an adequate quality of service. Knowing and improving the behavior of the surgical processes in a hospital can improve the number of patients that can be operated on using [...] Read more.

The definition of efficient and accurate health processes in hospitals is crucial for ensuring an adequate quality of service. Knowing and improving the behavior of the surgical processes in a hospital can improve the number of patients that can be operated on using the same resources. However, the measure of this process is usually made in an obtrusive way, forcing nurses to get information and time data, affecting the proper process and generating inaccurate data due to human errors during the stressful journey of health staff in the operating theater. The use of indoor location systems can take time information about the process in an unobtrusive way, freeing nurses, allowing them to engage in purely welfare work. However, it is necessary to present these data in a understandable way for health professionals, who cannot deal with large amounts of historical localization log data. The use of process mining techniques can deal with this problem, offering an easily understandable view of the process. In this paper, we present a tool and a process mining-based methodology that, using indoor location systems, enables health staff not only to represent the process, but to know precise information about the deployment of the process in an unobtrusive and transparent way. We have successfully tested this tool in a real surgical area with 3613 patients during February, March and April of 2015. Full article

(This article belongs to the Special Issue Sensors for Indoor Mapping and Navigation)

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14 pages, 687 KiB

Open AccessArticle

Enhanced Two-Factor Authentication and Key Agreement Using Dynamic Identities in Wireless Sensor Networks

by I-Pin Chang¹, Tian-Fu Lee^2,*, Tsung-Hung Lin³

and Chuan-Ming Liu⁴

¹ Department of Digital Applications, Kang Ning University, Tainan 70970, Taiwan

² Department of Medical Informatics, Tzu Chi University, No. 701, Zhongyang Road, Sec. 3, Hualien 97004, Taiwan

³ Department of Computer Science and Information Engineering, National Chin-Yi University of Technology, Taichung 41170, Taiwan

⁴ Department of Computer Science and Information Engineering, National Taipei University of Technology, Taipei 10608, Taiwan

Sensors 2015, 15(12), 29841-29854; https://doi.org/10.3390/s151229767 - 30 Nov 2015

Cited by 55 | Viewed by 6712

Abstract

Key agreements that use only password authentication are convenient in communication networks, but these key agreement schemes often fail to resist possible attacks, and therefore provide poor security compared with some other authentication schemes. To increase security, many authentication and key agreement schemes [...] Read more.

Key agreements that use only password authentication are convenient in communication networks, but these key agreement schemes often fail to resist possible attacks, and therefore provide poor security compared with some other authentication schemes. To increase security, many authentication and key agreement schemes use smartcard authentication in addition to passwords. Thus, two-factor authentication and key agreement schemes using smartcards and passwords are widely adopted in many applications. Vaidya et al. recently presented a two-factor authentication and key agreement scheme for wireless sensor networks (WSNs). Kim et al. observed that the Vaidya et al. scheme fails to resist gateway node bypassing and user impersonation attacks, and then proposed an improved scheme for WSNs. This study analyzes the weaknesses of the two-factor authentication and key agreement scheme of Kim et al., which include vulnerability to impersonation attacks, lost smartcard attacks and man-in-the-middle attacks, violation of session key security, and failure to protect user privacy. An efficient and secure authentication and key agreement scheme for WSNs based on the scheme of Kim et al. is then proposed. The proposed scheme not only solves the weaknesses of previous approaches, but also increases security requirements while maintaining low computational cost. Full article

(This article belongs to the Section Sensor Networks)

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16 pages, 2493 KiB

Open AccessArticle

Electromagnetic Modelling of Fiber Sensors for Low-Cost and High Sensitivity Temperature Monitoring

by William Scarcia, Giuseppe Palma, Mario Christian Falconi, Francesco De Leonardis, Vittorio M. N. Passaro

and Francesco Prudenzano^*

Department of Electrical and Information Engineering, Politecnico di Bari, via E. Orabona n. 4, Bari 70125, Italy

Sensors 2015, 15(12), 29855-29870; https://doi.org/10.3390/s151229770 - 30 Nov 2015

Cited by 22 | Viewed by 5686

Abstract

An accurate design of an innovative fiber optic temperature sensor is developed. The sensor is based on a cascade of three microstructured optical fibers (MOFs). In the first one a suitable cascade of long period gratings is designed into the core. A single [...] Read more.

An accurate design of an innovative fiber optic temperature sensor is developed. The sensor is based on a cascade of three microstructured optical fibers (MOFs). In the first one a suitable cascade of long period gratings is designed into the core. A single mode intermediate and a rare-earth activated Fabry-Perot optical cavity are the other two sensor MOF sections. An exhaustive theoretic feasibility investigation is performed employing computer code. The complete set-up for temperature monitoring can be obtained by utilizing only a low cost pump diode laser at 980 nm wavelength and a commercial optical power detector. The simulated sensitivity S = 315.1 μW/°C and the operation range ΔT = 100 °C is good enough for actual applications. Full article

(This article belongs to the Section Physical Sensors)

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Graphical abstract

11 pages, 2430 KiB

Open AccessArticle

Temperature Effects on the Wind Direction Measurement of 2D Solid Thermal Wind Sensors

by Bei Chen

, Yan-Qing Zhu, Zhenxiang Yi, Ming Qin and Qing-An Huang^*

Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 210096, China

Sensors 2015, 15(12), 29871-29881; https://doi.org/10.3390/s151229771 - 30 Nov 2015

Cited by 11 | Viewed by 8072

Abstract

For a two-dimensional solid silicon thermal wind sensor with symmetrical structure, the wind speed and direction information can be derived from the output voltages in two orthogonal directions, i.e., the north-south and east-west. However, the output voltages in these two directions will [...] Read more.

For a two-dimensional solid silicon thermal wind sensor with symmetrical structure, the wind speed and direction information can be derived from the output voltages in two orthogonal directions, i.e., the north-south and east-west. However, the output voltages in these two directions will vary linearly with the ambient temperature. Therefore, in this paper, a temperature model to study the temperature effect on the wind direction measurement has been developed. A theoretical analysis has been presented first, and then Finite Element Method (FEM) simulations have been performed. It is found that due to symmetrical structure of the thermal wind sensor, the temperature effects on the output signals in the north-south and east-west directions are highly similar. As a result, the wind direction measurement of the thermal wind sensor is approximately independent of the ambient temperature. The experimental results fit the theoretical analysis and simulation results very well. Full article

(This article belongs to the Collection Modeling, Testing and Reliability Issues in MEMS Engineering)

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11 pages, 2269 KiB

Open AccessArticle

Identification of Chinese Herbs Using a Sequencing-Free Nanostructured Electrochemical DNA Biosensor

by Yan Lei^1,2, Fan Yang¹, Lina Tang¹, Keli Chen^2,* and Guo-Jun Zhang^1,*

¹ School of Laboratory Medicine, Hubei University of Chinese Medicine, 1 Huangjia Lake West Road, Wuhan 430065, China

² School of Pharmacy, Hubei University of Chinese Medicine, 1 Huangjia Lake West Road, Wuhan 430065, China

Sensors 2015, 15(12), 29882-29892; https://doi.org/10.3390/s151229773 - 30 Nov 2015

Cited by 12 | Viewed by 6299

Abstract

Due to the nearly identical phenotypes and chemical constituents, it is often very challenging to accurately differentiate diverse species of a Chinese herbal genus. Although technologies including DNA barcoding have been introduced to help address this problem, they are generally time-consuming and require [...] Read more.

Due to the nearly identical phenotypes and chemical constituents, it is often very challenging to accurately differentiate diverse species of a Chinese herbal genus. Although technologies including DNA barcoding have been introduced to help address this problem, they are generally time-consuming and require expensive sequencing. Herein, we present a simple sequencing-free electrochemical biosensor, which enables easy differentiation between two closely related Fritillaria species. To improve its differentiation capability using trace amounts of DNA sample available from herbal extracts, a stepwise electrochemical deposition of reduced graphene oxide (RGO) and gold nanoparticles (AuNPs) was adopted to engineer a synergistic nanostructured sensing interface. By using such a nanofeatured electrochemical DNA (E-DNA) biosensor, two Chinese herbal species of Fritillaria (F. thunbergii and F. cirrhosa) were successfully discriminated at the DNA level, because a fragment of 16-mer sequence at the spacer region of the 5S-rRNA only exists in F. thunbergii. This E-DNA sensor was capable of identifying the target sequence in the range from 100 fM to 10 nM, and a detection limit as low as 11.7 fM (S/N = 3) was obtained. Importantly, this sensor was applied to detect the unique fragment of the PCR products amplified from F. thunbergii and F. cirrhosa, respectively. We anticipate that such a direct, sequencing-free sensing mode will ultimately pave the way towards a new generation of herb-identification strategies. Full article

(This article belongs to the Section Biosensors)

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17 pages, 3888 KiB

Open AccessArticle

Improved PPP Ambiguity Resolution Considering the Stochastic Characteristics of Atmospheric Corrections from Regional Networks

by Yihe Li^1,*

, Bofeng Li²

and Yang Gao¹

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

² College of Surveying and Geo-Informatics, Tongji University, Shanghai 200092, China

Sensors 2015, 15(12), 29893-29909; https://doi.org/10.3390/s151229772 - 30 Nov 2015

Cited by 14 | Viewed by 4849

Abstract

With the increased availability of regional reference networks, Precise Point Positioning (PPP) can achieve fast ambiguity resolution (AR) and precise positioning by assimilating the satellite fractional cycle biases (FCBs) and atmospheric corrections derived from these networks. In such processing, the atmospheric corrections are [...] Read more.

With the increased availability of regional reference networks, Precise Point Positioning (PPP) can achieve fast ambiguity resolution (AR) and precise positioning by assimilating the satellite fractional cycle biases (FCBs) and atmospheric corrections derived from these networks. In such processing, the atmospheric corrections are usually treated as deterministic quantities. This is however unrealistic since the estimated atmospheric corrections obtained from the network data are random and furthermore the interpolated corrections diverge from the realistic corrections. This paper is dedicated to the stochastic modelling of atmospheric corrections and analyzing their effects on the PPP AR efficiency. The random errors of the interpolated corrections are processed as two components: one is from the random errors of estimated corrections at reference stations, while the other arises from the atmospheric delay discrepancies between reference stations and users. The interpolated atmospheric corrections are then applied by users as pseudo-observations with the estimated stochastic model. Two data sets are processed to assess the performance of interpolated corrections with the estimated stochastic models. The results show that when the stochastic characteristics of interpolated corrections are properly taken into account, the successful fix rate reaches 93.3% within 5 min for a medium inter-station distance network and 80.6% within 10 min for a long inter-station distance network. Full article

(This article belongs to the Section Remote Sensors)

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13 pages, 2098 KiB

Open AccessArticle

Multiple-Point Temperature Gradient Algorithm for Ring Laser Gyroscope Bias Compensation

by Geng Li, Pengfei Zhang, Guo Wei, Yuanping Xie, Xudong Yu and Xingwu Long^*

College of Opto-electrics Science and Engineering, National University of Defense Technology, Changsha 410073, China

Sensors 2015, 15(12), 29910-29922; https://doi.org/10.3390/s151229777 - 30 Nov 2015

Cited by 12 | Viewed by 6406

Abstract

To further improve ring laser gyroscope (RLG) bias stability, a multiple-point temperature gradient algorithm is proposed for RLG bias compensation in this paper. Based on the multiple-point temperature measurement system, a complete thermo-image of the RLG block is developed. Combined with the multiple-point [...] Read more.

To further improve ring laser gyroscope (RLG) bias stability, a multiple-point temperature gradient algorithm is proposed for RLG bias compensation in this paper. Based on the multiple-point temperature measurement system, a complete thermo-image of the RLG block is developed. Combined with the multiple-point temperature gradients between different points of the RLG block, the particle swarm optimization algorithm is used to tune the support vector machine (SVM) parameters, and an optimized design for selecting the thermometer locations is also discussed. The experimental results validate the superiority of the introduced method and enhance the precision and generalizability in the RLG bias compensation model. Full article

(This article belongs to the Section Physical Sensors)

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1 pages, 141 KiB

Open AccessAddendum

Addendum: Li, Y.; Shi, X.; Wei, L.; Zou, J.; Chen, F. Assigning Main Orientation to an EOH Descriptor on Multispectral Images. Sensors 2015, 15, 15595–15610.

by Yong Li^1,*, Xiang Shi¹, Lijun Wei¹, Junwei Zou¹ and Fang Chen²

¹ Beijing University of Posts and Telecommunications, School of Electronic Engineering, Rd. Xitucheng 10#, Beijing 100876, China

² Beijing Anzhen Hospital, Capital Medical University and Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing 100029, China

Sensors 2015, 15(12), 29923; https://doi.org/10.3390/s151229776 - 30 Nov 2015

Viewed by 3951

Abstract

The authors wish to update the Acknowledgments section in their paper published in Sensors [1], doi:10.3390/s150715595, https://www.mdpi.com/1424-8220/15/7/15595. [...] Full article

(This article belongs to the Section Remote Sensors)

14 pages, 2610 KiB

Open AccessArticle

Effect of Pore Size and Film Thickness on Gold-Coated Nanoporous Anodic Aluminum Oxide Substrates for Surface-Enhanced Raman Scattering Sensor

by Aschalew Kassu^1,*, Carlton Farley², Anup Sharma², Wonkyu Kim³ and Junpeng Guo³

¹ Department of Engineering, Construction Management & Ind. Tech., Alabama A & M University, 4900 Meridian Street, Normal, AL 35762, USA

² Department of Physics, Chemistry and Mathematics, Alabama A & M University, 4900 Meridian Street, Normal, AL 35762, USA

³ Department of Electrical and Computer Engineering, University of Alabama in Huntsville, 301 Sparkman Dr., Huntsville, AL 35899, USA

Sensors 2015, 15(12), 29924-29937; https://doi.org/10.3390/s151229778 - 30 Nov 2015

Cited by 23 | Viewed by 8161

Abstract

A sensitive surface enhanced Raman scattering chemical sensor is demonstrated by using inexpensive gold-coated nanoporous anodic aluminum oxide substrates. To optimize the performance of the substrates for sensing by the Surface-enhanced Raman scattering (SERS) technique, the size of the nanopores is varied from [...] Read more.

A sensitive surface enhanced Raman scattering chemical sensor is demonstrated by using inexpensive gold-coated nanoporous anodic aluminum oxide substrates. To optimize the performance of the substrates for sensing by the Surface-enhanced Raman scattering (SERS) technique, the size of the nanopores is varied from 18 nm to 150 nm and the gold film thickness is varied from 30 nm to 120 nm. The sensitivity of gold-coated nanoporous surface enhanced Raman scattering sensor is characterized by detecting low concentrations of Rhodamine 6G laser dye molecules. The morphology of the SERS substrates is characterized by atomic force microscopy. Optical properties of the nanoporous SERS substrates including transmittance, reflectance, and absorbance are also investigated. Relative signal enhancement is plotted for a range of substrate parameters and a detection limit of 10⁻⁶ M is established. Full article

(This article belongs to the Special Issue The Use of New and/or Improved Materials for Sensing Applications)

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12 pages, 5135 KiB

Open AccessArticle

Simulated and Real Sheet-of-Light 3D Object Scanning Using a-Si:H Thin Film PSD Arrays

by Javier Contreras^1,*, Josep Tornero¹, Isabel Ferreira², Rodrigo Martins^2,*, Luis Gomes³ and Elvira Fortunato²

¹ Institute of Design and Manufacturing, Technical University of Valencia, CPI, Edif. 8G, 46022 Valencia, Spain

² CENIMAT/I3N, Department of Material Science, Faculty of Science and Technology, FCT, New University of Lisbon and CEMOP/UNINOVA, 2829-516 Caparica, Portugal

³ Department of Electrical Engineering, Faculty of Science and Technology, FCT, New University of Lisbon, and CTS/UNINOVA, Campus da Caparica, 2928-516 Caparica, Portugal

Sensors 2015, 15(12), 29938-29949; https://doi.org/10.3390/s151229779 - 30 Nov 2015

Cited by 2 | Viewed by 7244

Abstract

A MATLAB/SIMULINK software simulation model (structure and component blocks) has been constructed in order to view and analyze the potential of the PSD (Position Sensitive Detector) array concept technology before it is further expanded or developed. This simulation allows changing most of its [...] Read more.

A MATLAB/SIMULINK software simulation model (structure and component blocks) has been constructed in order to view and analyze the potential of the PSD (Position Sensitive Detector) array concept technology before it is further expanded or developed. This simulation allows changing most of its parameters, such as the number of elements in the PSD array, the direction of vision, the viewing/scanning angle, the object rotation, translation, sample/scan/simulation time, etc. In addition, results show for the first time the possibility of scanning an object in 3D when using an a-Si:H thin film 128 PSD array sensor and hardware/software system. Moreover, this sensor technology is able to perform these scans and render 3D objects at high speeds and high resolutions when using a sheet-of-light laser within a triangulation platform. As shown by the simulation, a substantial enhancement in 3D object profile image quality and realism can be achieved by increasing the number of elements of the PSD array sensor as well as by achieving an optimal position response from the sensor since clearly the definition of the 3D object profile depends on the correct and accurate position response of each detector as well as on the size of the PSD array. Full article

(This article belongs to the Special Issue Imaging: Sensors and Technologies)

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8 pages, 2972 KiB

Open AccessArticle

A Single Eu-Doped In₂O₃ Nanobelt Device for Selective H₂S Detection

by Weiwu Chen

, Yingkai Liu^*, Zhaojun Qin, Yuemei Wu, Shuanghui Li and Peng Ai

Institute of Physics and Electronic Information Technology, Yunnan Normal University, Kunming 650500, China

Sensors 2015, 15(12), 29950-29957; https://doi.org/10.3390/s151229775 - 30 Nov 2015

Cited by 37 | Viewed by 6796

Abstract

Eu-doped In₂O₃ nanobelts (Eu-In₂O₃ NBs) and pure In₂O₃ nanobelts (In₂O₃ NBs) are synthesized by the carbon thermal reduction method. Single nanobelt sensors are fabricated via an ion beam deposition system with [...] Read more.

Eu-doped In₂O₃ nanobelts (Eu-In₂O₃ NBs) and pure In₂O₃ nanobelts (In₂O₃ NBs) are synthesized by the carbon thermal reduction method. Single nanobelt sensors are fabricated via an ion beam deposition system with a mesh-grid mask. The gas-sensing response properties of the Eu-In₂O₃ NB device and its undoped counterpart are investigated with several kinds of gases (including H₂S, CO, NO₂, HCHO, and C₂H₅OH) at different concentrations and different temperatures. It is found that the response of the Eu-In₂O₃ NB device to 100 ppm of H₂S is the best among these gases and the sensitivity reaches 5.74, which is five times that of pure In₂O₃ NB at 260 °C. We also found that the former has an excellent sensitive response and great selectivity to H₂S compared to the latter. Besides, there is a linear relationship between the response and H₂S concentration when its concentration changes from 5 to 100 ppm and from 100 to 1000 ppm. The response/recovery time is quite short and remains stable with an increase of H₂S concentration. These results mean that the doping of Eu can improve the gas-sensing performance of In₂O₃ NB effectually. Full article

(This article belongs to the Special Issue Gas Sensors—Designs and Applications)

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12 pages, 1792 KiB

Open AccessArticle

A Network Topology Control and Identity Authentication Protocol with Support for Movable Sensor Nodes

by Ying Zhang¹

, Wei Chen^2,*, Jixing Liang¹, Bingxin Zheng¹ and Shengming Jiang¹

¹ College of Information Engineering, Shanghai Maritime University, Shanghai 201306, China

² Department of Computer Science, Tennessee State University, Nashville, TN 37209, USA

Sensors 2015, 15(12), 29958-29969; https://doi.org/10.3390/s151229782 - 1 Dec 2015

Cited by 19 | Viewed by 6535

Abstract

It is expected that in the near future wireless sensor network (WSNs) will be more widely used in the mobile environment, in applications such as Autonomous Underwater Vehicles (AUVs) for marine monitoring and mobile robots for environmental investigation. The sensor nodes’ mobility can [...] Read more.

It is expected that in the near future wireless sensor network (WSNs) will be more widely used in the mobile environment, in applications such as Autonomous Underwater Vehicles (AUVs) for marine monitoring and mobile robots for environmental investigation. The sensor nodes’ mobility can easily cause changes to the structure of a network topology, and lead to the decline in the amount of transmitted data, excessive energy consumption, and lack of security. To solve these problems, a kind of efficient Topology Control algorithm for node Mobility (TCM) is proposed. In the topology construction stage, an efficient clustering algorithm is adopted, which supports sensor node movement. It can ensure the balance of clustering, and reduce the energy consumption. In the topology maintenance stage, the digital signature authentication based on Error Correction Code (ECC) and the communication mechanism of soft handover are adopted. After verifying the legal identity of the mobile nodes, secure communications can be established, and this can increase the amount of data transmitted. Compared to some existing schemes, the proposed scheme has significant advantages regarding network topology stability, amounts of data transferred, lifetime and safety performance of the network. Full article

(This article belongs to the Special Issue Security and Privacy in Sensor Networks)

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14 pages, 1715 KiB

Open AccessArticle

Assessment of the Contribution of BeiDou GEO, IGSO, and MEO Satellites to PPP in Asia—Pacific Region

by Qile Zhao¹, Chen Wang¹, Jing Guo^1,*

and Xianglin Liu²

¹ GNSS Research Center, Wuhan University, No. 129 Luoyu Road, Wuhan 430079, China

² Fugro Intersite B.V., Leidschendam 2263 HW, The Netherlands

Sensors 2015, 15(12), 29970-29983; https://doi.org/10.3390/s151229780 - 1 Dec 2015

Cited by 23 | Viewed by 7901

Abstract

In contrast to the US Global Positioning System (GPS), the Russian Global Navigation Satellite System (GLONASS) and the European Galileo, the developing Chinese BeiDou satellite navigation system (BDS) consists of not only Medium Earth Orbit (MEO), but also Geostationary Orbit (GEO) as well [...] Read more.

In contrast to the US Global Positioning System (GPS), the Russian Global Navigation Satellite System (GLONASS) and the European Galileo, the developing Chinese BeiDou satellite navigation system (BDS) consists of not only Medium Earth Orbit (MEO), but also Geostationary Orbit (GEO) as well as Inclined Geosynchronous Orbit (IGSO) satellites. In this study, the Precise Point Positioning (PPP) and PPP with Integer Ambiguity Resolution (IAR) are obtained. The contributions of these three different types of BDS satellites to PPP in Asia–Pacific region are assessed using data from selected 20 sites over more than four weeks. By using various PPP cases with different satellite combinations, in general, the largest contribution of BDS IGSO among the three kinds of BDS satellites to the reduction of convergence time and the improvement of positioning accuracy, particularly in the east direction, is identified. These PPP cases include static BDS only solutions and static/kinematic ambiguity-float and -fixed PPP with the combination of GPS and BDS. The statistical results demonstrate that the inclusion of BDS GEO and MEO satellites can improve the observation condition and result in better PPP performance as well. When combined with GPS, the contribution of BDS to the reduction of convergence time is, however, not as significant as that of GLONASS. As far as the positioning accuracy is concerned, GLONASS improves the accuracy in vertical component more than BDS does, whereas similar improvement in horizontal component can be achieved by inclusion of BDS IGSO and MEO as GLONASS. Full article

(This article belongs to the Section Remote Sensors)

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13 pages, 6595 KiB

Open AccessArticle

Optimized Design of the SGA-WZ Strapdown Airborne Gravimeter Temperature Control System

by Juliang Cao, Minghao Wang^*, Shaokun Cai, Kaidong Zhang, Danni Cong and Meiping Wu

College of Mechatronics and Automation, National University of Defense Technology, Changsha 410072, China

Sensors 2015, 15(12), 29984-29996; https://doi.org/10.3390/s151229781 - 1 Dec 2015

Cited by 21 | Viewed by 6692

Abstract

The temperature control system is one of the most important subsystems of the strapdown airborne gravimeter. Because the quartz flexible accelerometer based on springy support technology is the core sensor in the strapdown airborne gravimeter and the magnet steel in the electromagnetic force [...] Read more.

The temperature control system is one of the most important subsystems of the strapdown airborne gravimeter. Because the quartz flexible accelerometer based on springy support technology is the core sensor in the strapdown airborne gravimeter and the magnet steel in the electromagnetic force equilibrium circuits of the quartz flexible accelerometer is greatly affected by temperature, in order to guarantee the temperature control precision and minimize the effect of temperature on the gravimeter, the SGA-WZ temperature control system adopts a three-level control method. Based on the design experience of the SGA-WZ-01, the SGA-WZ-02 temperature control system came out with a further optimized design. In 1st level temperature control, thermoelectric cooler is used to conquer temperature change caused by hot weather. The experiments show that the optimized stability of 1st level temperature control is about 0.1 °C and the max cool down capability is about 10 °C. The temperature field is analyzed in the 2nd and 3rd level temperature control using the finite element analysis software ANSYS. The 2nd and 3rd level temperature control optimization scheme is based on the foundation of heat analysis. The experimental results show that static accuracy of SGA-WZ-02 reaches 0.21 mGal/24 h, with internal accuracy being 0.743 mGal/4.8 km and external accuracy being 0.37 mGal/4.8 km compared with the result of the GT-2A, whose internal precision is superior to 1 mGal/4.8 km and all of them are better than those in SGA-WZ-01. Full article

(This article belongs to the Section Physical Sensors)

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14 pages, 1475 KiB

Open AccessArticle

Node Non-Uniform Deployment Based on Clustering Algorithm for Underwater Sensor Networks

by Peng Jiang^1,2,*, Jun Liu^1,2 and Feng Wu^1,2

¹ Key Lab for IOT and Information Fusion Technology of Zhejiang, Hangzhou 310018, China

² College of Automation, Hangzhou Dianzi University, Hangzhou 310018, China

Sensors 2015, 15(12), 29997-30010; https://doi.org/10.3390/s151229786 - 1 Dec 2015

Cited by 24 | Viewed by 5972

Abstract

A node non-uniform deployment based on clustering algorithm for underwater sensor networks (UWSNs) is proposed in this study. This algorithm is proposed because optimizing network connectivity rate and network lifetime is difficult for the existing node non-uniform deployment algorithms under the premise of [...] Read more.

A node non-uniform deployment based on clustering algorithm for underwater sensor networks (UWSNs) is proposed in this study. This algorithm is proposed because optimizing network connectivity rate and network lifetime is difficult for the existing node non-uniform deployment algorithms under the premise of improving the network coverage rate for UWSNs. A high network connectivity rate is achieved by determining the heterogeneous communication ranges of nodes during node clustering. Moreover, the concept of aggregate contribution degree is defined, and the nodes with lower aggregate contribution degrees are used to substitute the dying nodes to decrease the total movement distance of nodes and prolong the network lifetime. Simulation results show that the proposed algorithm can achieve a better network coverage rate and network connectivity rate, as well as decrease the total movement distance of nodes and prolong the network lifetime. Full article

(This article belongs to the Special Issue Underwater Sensor Nodes and Underwater Sensor Networks 2016)

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21 pages, 3390 KiB

Open AccessReview

Microfluidics Integrated Biosensors: A Leading Technology towards Lab-on-a-Chip and Sensing Applications

by George Luka¹, Ali Ahmadi¹, Homayoun Najjaran¹, Evangelyn Alocilja², Maria DeRosa³, Kirsten Wolthers¹, Ahmed Malki⁴, Hassan Aziz⁴, Asmaa Althani^4,5 and Mina Hoorfar^1,*

¹ School of Engineering, University of British Columbia, Kelowna, BC V1V 1V7, Canada

² Nano-Biosensors Laboratory, Department of Biosystems and Agricultural Engineering, Michigan State University, 524 S. Shaw Lane, Room 115, East Lansing, MI 48224, USA

³ Carleton University, Department of Chemistry and Institute of Biochemistry, 225 Steacie Building 1125 Colonel By Drive Ottawa, ON K1S 5B6, Canada

⁴ Department of Health Sciences, College of Arts and Sciences, Qatar University, 2713 Doha, Qatar

⁵ Biomedical Research Center, Qatar University, 2713 Doha, Qatar

Sensors 2015, 15(12), 30011-30031; https://doi.org/10.3390/s151229783 - 1 Dec 2015

Cited by 465 | Viewed by 34230

Abstract

A biosensor can be defined as a compact analytical device or unit incorporating a biological or biologically derived sensitive recognition element immobilized on a physicochemical transducer to measure one or more analytes. Microfluidic systems, on the other hand, provide throughput processing, enhance transport [...] Read more.

A biosensor can be defined as a compact analytical device or unit incorporating a biological or biologically derived sensitive recognition element immobilized on a physicochemical transducer to measure one or more analytes. Microfluidic systems, on the other hand, provide throughput processing, enhance transport for controlling the flow conditions, increase the mixing rate of different reagents, reduce sample and reagents volume (down to nanoliter), increase sensitivity of detection, and utilize the same platform for both sample preparation and detection. In view of these advantages, the integration of microfluidic and biosensor technologies provides the ability to merge chemical and biological components into a single platform and offers new opportunities for future biosensing applications including portability, disposability, real-time detection, unprecedented accuracies, and simultaneous analysis of different analytes in a single device. This review aims at representing advances and achievements in the field of microfluidic-based biosensing. The review also presents examples extracted from the literature to demonstrate the advantages of merging microfluidic and biosensing technologies and illustrate the versatility that such integration promises in the future biosensing for emerging areas of biological engineering, biomedical studies, point-of-care diagnostics, environmental monitoring, and precision agriculture. Full article

(This article belongs to the Section Biosensors)

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1 pages, 145 KiB

Open AccessAddendum

Addendum: Li, Y.; Jing, J.; Jin, H.; Qiao, W. Building Keypoint Mappings on Multispectral Images by a Cascade of Classifiers with a Resurrection Mechanism. Sensors 2015, 15, 11769–11786

by Yong Li^*, Jing Jing, Hongbin Jin and Wei Qiao

School of Electronic Engineering, Beijing University of Posts and Telecommunications, Rd. Xitucheng 10#, Beijing 100876, China

Sensors 2015, 15(12), 30032; https://doi.org/10.3390/s151229784 - 2 Dec 2015

Viewed by 3770

Abstract

The authors wish to update the Acknowledgments in their paper published in Sensors [1], [...] Full article

(This article belongs to the Section Remote Sensors)

29 pages, 6945 KiB

Open AccessReview

A Primer on Autonomous Aerial Vehicle Design

by Hugo H. G. Coppejans and Herman C. Myburgh^*

Department of Electrical, Electronic and Computer Engineering, University of Pretoria, Pretoria 0002, South Africa

Sensors 2015, 15(12), 30033-30061; https://doi.org/10.3390/s151229785 - 2 Dec 2015

Cited by 9 | Viewed by 9235

Abstract

There is a large amount of research currently being done on autonomous micro-aerial vehicles (MAV), such as quadrotor helicopters or quadcopters. The ability to create a working autonomous MAV depends mainly on integrating a simultaneous localization and mapping (SLAM) solution with the rest [...] Read more.

There is a large amount of research currently being done on autonomous micro-aerial vehicles (MAV), such as quadrotor helicopters or quadcopters. The ability to create a working autonomous MAV depends mainly on integrating a simultaneous localization and mapping (SLAM) solution with the rest of the system. This paper provides an introduction for creating an autonomous MAV for enclosed environments, aimed at students and professionals alike. The standard autonomous system and MAV automation are discussed, while we focus on the core concepts of SLAM systems and trajectory planning algorithms. The advantages and disadvantages of using remote processing are evaluated, and recommendations are made regarding the viability of on-board processing. Recommendations are made regarding best practices to serve as a guideline for aspirant MAV designers. Full article

(This article belongs to the Section Physical Sensors)

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14 pages, 2308 KiB

Open AccessArticle

Electronic Tongue Response to Chemicals in Orange Juice that Change Concentration in Relation to Harvest Maturity and Citrus Greening or Huanglongbing (HLB) Disease

by Smita Raithore¹, Jinhe Bai¹

, Anne Plotto¹, John Manthey¹, Mike Irey² and Elizabeth Baldwin^1,*

¹ USDA-ARS, U.S. Horticultural Research Laboratory, 2001 South Rock Road, Fort Pierce, FL 34945, USA

² US Sugar Corp., 111 Ponce de Leon Ave, Clewiston, FL 33400, USA

Sensors 2015, 15(12), 30062-30075; https://doi.org/10.3390/s151229787 - 2 Dec 2015

Cited by 27 | Viewed by 7401

Abstract

In an earlier study, an electronic tongue system (e-tongue) has been used to differentiate between orange juice made from healthy fruit and from fruit affected by the citrus greening or Huanglongbing (HLB) disease. This study investigated the reaction of an e-tongue system to [...] Read more.

In an earlier study, an electronic tongue system (e-tongue) has been used to differentiate between orange juice made from healthy fruit and from fruit affected by the citrus greening or Huanglongbing (HLB) disease. This study investigated the reaction of an e-tongue system to the main chemicals in orange juice that impact flavor and health benefits and are also impacted by HLB. Orange juice was spiked with sucrose (0.2–5.0 g/100 mL), citric acid (0.1%–3.0% g/100 mL) and potassium chloride (0.1–3.0 g/100 mL) as well as the secondary metabolites nomilin (1–30 µg/mL), limonin (1–30 µg/mL), limonin glucoside (30–200 µg/mL), hesperidin (30–400 µg/mL) and hesperetin (30–400 µg/mL). Performance of Alpha MOS sensor sets #1 (pharmaceutical) and #5 (food) were compared for the same samples, with sensor set #1 generally giving better separation than sensor set #5 for sucrose, sensor set #5 giving better separation for nomilin and limonin, both sets being efficient at separating citric acid, potassium chloride, hesperitin and limonin glucoside, and neither set discriminating hesperidin efficiently. Orange juice made from fruit over the harvest season and from fruit harvested from healthy or HLB-affected trees were separated by harvest maturity, disease state and disease severity. Full article

(This article belongs to the Section Chemical Sensors)

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17 pages, 1639 KiB

Open AccessArticle

Event-Based Control Strategy for Mobile Robots in Wireless Environments

by Rafael Socas^*

, Sebastián Dormido

, Raquel Dormido

and Ernesto Fabregas

Departamento de Informática y Automática, Universidad Nacional de Educación a Distancia, Juan del Rosal 16, Madrid 28040, Spain

Sensors 2015, 15(12), 30076-30092; https://doi.org/10.3390/s151229796 - 2 Dec 2015

Cited by 21 | Viewed by 7060

Abstract

In this paper, a new event-based control strategy for mobile robots is presented. It has been designed to work in wireless environments where a centralized controller has to interchange information with the robots over an RF (radio frequency) interface. The event-based architectures have [...] Read more.

In this paper, a new event-based control strategy for mobile robots is presented. It has been designed to work in wireless environments where a centralized controller has to interchange information with the robots over an RF (radio frequency) interface. The event-based architectures have been developed for differential wheeled robots, although they can be applied to other kinds of robots in a simple way. The solution has been checked over classical navigation algorithms, like wall following and obstacle avoidance, using scenarios with a unique or multiple robots. A comparison between the proposed architectures and the classical discrete-time strategy is also carried out. The experimental results shows that the proposed solution has a higher efficiency in communication resource usage than the classical discrete-time strategy with the same accuracy. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Spain 2015)

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11 pages, 902 KiB

Open AccessArticle

GNSS Single Frequency, Single Epoch Reliable Attitude Determination Method with Baseline Vector Constraint

by Ang Gong, Xiubin Zhao, Chunlei Pang^*, Rong Duan and Yong Wang

Information and Navigation School, Air Force Engineering University, No.1 FengHao Road, LianHu District , Xi’an 710077, China

Sensors 2015, 15(12), 30093-30103; https://doi.org/10.3390/s151229774 - 2 Dec 2015

Cited by 30 | Viewed by 5403

Abstract

For Global Navigation Satellite System (GNSS) single frequency, single epoch attitude determination, this paper proposes a new reliable method with baseline vector constraint. First, prior knowledge of baseline length, heading, and pitch obtained from other navigation equipment or sensors are used to reconstruct [...] Read more.

For Global Navigation Satellite System (GNSS) single frequency, single epoch attitude determination, this paper proposes a new reliable method with baseline vector constraint. First, prior knowledge of baseline length, heading, and pitch obtained from other navigation equipment or sensors are used to reconstruct objective function rigorously. Then, searching strategy is improved. It substitutes gradually Enlarged ellipsoidal search space for non-ellipsoidal search space to ensure correct ambiguity candidates are within it and make the searching process directly be carried out by least squares ambiguity decorrelation algorithm (LAMBDA) method. For all vector candidates, some ones are further eliminated by derived approximate inequality, which accelerates the searching process. Experimental results show that compared to traditional method with only baseline length constraint, this new method can utilize a priori baseline three-dimensional knowledge to fix ambiguity reliably and achieve a high success rate. Experimental tests also verify it is not very sensitive to baseline vector error and can perform robustly when angular error is not great. Full article

(This article belongs to the Section Physical Sensors)

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11 pages, 1296 KiB

Open AccessArticle

Improving GLONASS Precise Orbit Determination through Data Connection

by Yang Liu^1,2, Maorong Ge², Chuang Shi¹, Yidong Lou^1,*, Jens Wickert²

and Harald Schuh²

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

² German Research Center for Geosciences (GFZ), Telegrafenberg, Potsdam 14473, Germany

Sensors 2015, 15(12), 30104-30114; https://doi.org/10.3390/s151229790 - 2 Dec 2015

Cited by 3 | Viewed by 5874

Abstract

In order to improve the precision of GLONASS orbits, this paper presents a method to connect the data segments of a single station-satellite pair to increase the observation continuity and, consequently, the strength of the precise orbit determination (POD) solution. In this method, [...] Read more.

In order to improve the precision of GLONASS orbits, this paper presents a method to connect the data segments of a single station-satellite pair to increase the observation continuity and, consequently, the strength of the precise orbit determination (POD) solution. In this method, for each GLONASS station-satellite pair, the wide-lane ambiguities derived from the Melbourne–Wübbena combination are statistically tested and corrected for phase integer offsets and then the same is carried out for the narrow-lane ambiguities calculated from the POD solution. An experimental validation was carried out using one-month GNSS data of a global network with 175 IGS stations. The result shows that, on average, 27.1% of the GLONASS station-satellite pairs with multiple data segments could be connected to a single long observation arc and, thus, only one ambiguity parameter was estimated. Using the connected data, the GLONASS orbit overlapping RMS at the day boundaries could be reduced by 19.2% in ideal cases with an averaged reduction of about 6.3%. Full article

(This article belongs to the Section Physical Sensors)

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11 pages, 786 KiB

Open AccessArticle

Low Complexity HEVC Encoder for Visual Sensor Networks

by Zhaoqing Pan^1,2,*

, Liming Chen¹ and Xingming Sun¹

¹ School of Computer and Software, Jiangsu Engineering Center of Network Monitoring, Nanjing University of Information Science and Technology, Nanjing 210044, China

² School of Computer Science and Engineering, Hebei University of Technology, Tianjin 300401, China

Sensors 2015, 15(12), 30115-30125; https://doi.org/10.3390/s151229788 - 2 Dec 2015

Cited by 15 | Viewed by 5636

Abstract

Visual sensor networks (VSNs) can be widely applied in security surveillance, environmental monitoring, smart rooms, etc. However, with the increased number of camera nodes in VSNs, the volume of the visual information data increases significantly, which becomes a challenge for storage, processing [...] Read more.

Visual sensor networks (VSNs) can be widely applied in security surveillance, environmental monitoring, smart rooms, etc. However, with the increased number of camera nodes in VSNs, the volume of the visual information data increases significantly, which becomes a challenge for storage, processing and transmitting the visual data. The state-of-the-art video compression standard, high efficiency video coding (HEVC), can effectively compress the raw visual data, while the higher compression rate comes at the cost of heavy computational complexity. Hence, reducing the encoding complexity becomes vital for the HEVC encoder to be used in VSNs. In this paper, we propose a fast coding unit (CU) depth decision method to reduce the encoding complexity of the HEVC encoder for VSNs. Firstly, the content property of the CU is analyzed. Then, an early CU depth decision method and a low complexity distortion calculation method are proposed for the CUs with homogenous content. Experimental results show that the proposed method achieves 71.91% on average encoding time savings for the HEVC encoder for VSNs. Full article

(This article belongs to the Section Sensor Networks)

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16 pages, 1781 KiB

Open AccessArticle

Pupil and Glint Detection Using Wearable Camera Sensor and Near-Infrared LED Array

by Jianzhong Wang, Guangyue Zhang and Jiadong Shi^*

School of Mechatronical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China

Sensors 2015, 15(12), 30126-30141; https://doi.org/10.3390/s151229792 - 2 Dec 2015

Cited by 25 | Viewed by 8842

Abstract

This paper proposes a novel pupil and glint detection method for gaze tracking system using a wearable camera sensor and near-infrared LED array. A novel circular ring rays location (CRRL) method is proposed for pupil boundary points detection. Firstly, improved Otsu optimal threshold [...] Read more.

This paper proposes a novel pupil and glint detection method for gaze tracking system using a wearable camera sensor and near-infrared LED array. A novel circular ring rays location (CRRL) method is proposed for pupil boundary points detection. Firstly, improved Otsu optimal threshold binarization, opening-and-closing operation and projection of 3D gray-level histogram are utilized to estimate rough pupil center and radius. Secondly, a circular ring area including pupil edge inside is determined according to rough pupil center and radius. Thirdly, a series of rays are shot from inner to outer ring to collect pupil boundary points. Interference points are eliminated by calculating gradient amplitude. At last, an improved total least squares is proposed to fit collected pupil boundary points. In addition, the improved total least squares developed is utilized for the solution of Gaussian function deformation to calculate glint center. The experimental results show that the proposed method is more robust and accurate than conventional detection methods. When interference factors such as glints and natural light reflection are located on pupil contour, pupil boundary points and center can be detected accurately. The proposed method contributes to enhance stability, accuracy and real-time quality of gaze tracking system. Full article

(This article belongs to the Section Physical Sensors)

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23 pages, 2949 KiB

Open AccessArticle

A Novel Hybrid Intelligent Indoor Location Method for Mobile Devices by Zones Using Wi-Fi Signals

by Manuel Castañón–Puga^*

, Abby Stephanie Salazar, Leocundo Aguilar, Carelia Gaxiola-Pacheco

and Guillermo Licea

Facultad de Ciencias Químicas e Ingeniería, Universidad Autónoma de Baja California, Calzada Universidad 14418, Tijuana 22390, Mexico

Sensors 2015, 15(12), 30142-30164; https://doi.org/10.3390/s151229791 - 2 Dec 2015

Cited by 12 | Viewed by 6238

Abstract

The increasing use of mobile devices in indoor spaces brings challenges to location methods. This work presents a hybrid intelligent method based on data mining and Type-2 fuzzy logic to locate mobile devices in an indoor space by zones using Wi-Fi signals from [...] Read more.

The increasing use of mobile devices in indoor spaces brings challenges to location methods. This work presents a hybrid intelligent method based on data mining and Type-2 fuzzy logic to locate mobile devices in an indoor space by zones using Wi-Fi signals from selected access points (APs). This approach takes advantage of wireless local area networks (WLANs) over other types of architectures and implements the complete method in a mobile application using the developed tools. Besides, the proposed approach is validated by experimental data obtained from case studies and the cross-validation technique. For the purpose of generating the fuzzy rules that conform to the Takagi–Sugeno fuzzy system structure, a semi-supervised data mining technique called subtractive clustering is used. This algorithm finds centers of clusters from the radius map given by the collected signals from APs. Measurements of Wi-Fi signals can be noisy due to several factors mentioned in this work, so this method proposed the use of Type-2 fuzzy logic for modeling and dealing with such uncertain information. Full article

(This article belongs to the Special Issue Sensors for Indoor Mapping and Navigation)

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22 pages, 2959 KiB

Open AccessArticle

Abnormal Condition Monitoring of Workpieces Based on RFID for Wisdom Manufacturing Workshops

by Cunji Zhang^1,2,*

, Xifan Yao¹ and Jianming Zhang¹

¹ School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China

² Department of Information Engineering, Guangxi College of Water Resources and Electric Power, Nanning 530023, China

Sensors 2015, 15(12), 30165-30186; https://doi.org/10.3390/s151229789 - 3 Dec 2015

Cited by 11 | Viewed by 10033

Abstract

Radio Frequency Identification (RFID) technology has been widely used in many fields. However, previous studies have mainly focused on product life cycle tracking, and there are few studies on real-time status monitoring of workpieces in manufacturing workshops. In this paper, a wisdom manufacturing [...] Read more.

Radio Frequency Identification (RFID) technology has been widely used in many fields. However, previous studies have mainly focused on product life cycle tracking, and there are few studies on real-time status monitoring of workpieces in manufacturing workshops. In this paper, a wisdom manufacturing model is introduced, a sensing-aware environment for a wisdom manufacturing workshop is constructed, and RFID event models are defined. A synthetic data cleaning method is applied to clean the raw RFID data. The Complex Event Processing (CEP) technology is adopted to monitor abnormal conditions of workpieces in real time. The RFID data cleaning method and data mining technology are examined by simulation and physical experiments. The results show that the synthetic data cleaning method preprocesses data well. The CEP based on the Rifidi^® Edge Server technology completed abnormal condition monitoring of workpieces in real time. This paper reveals the importance of RFID spatial and temporal data analysis in real-time status monitoring of workpieces in wisdom manufacturing workshops. Full article

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

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12 pages, 2376 KiB

Open AccessArticle

Development of a Wireless and Passive SAW-Based Chemical Sensor for Organophosphorous Compound Detection

by Fang-Qian Xu¹, Wen Wang^2,*, Xu-Feng Xue², Hao-Liang Hu², Xin-Lu Liu² and Yong Pan³

¹ Zhejiang University of Media and Communications, Hangzhou 310018, China

² State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, No.21, North 4th Ring West Road, Beijing 100190, China

³ State Key Laboratory of NBC Protection for Civilian, Yangfang, Changping District, Beijing 102205, China

Sensors 2015, 15(12), 30187-30198; https://doi.org/10.3390/s151229793 - 3 Dec 2015

Cited by 23 | Viewed by 8201

Abstract

A new wireless and passive surface acoustic wave (SAW)-based chemical sensor for organophosphorous compound (OC) detection is presented. A 434 MHz reflective delay line configuration composed by single phase unidirectional transducers (SPUDTs) and three shorted reflectors was fabricated on YZ LiNbO₃ piezoelectric [...] Read more.

A new wireless and passive surface acoustic wave (SAW)-based chemical sensor for organophosphorous compound (OC) detection is presented. A 434 MHz reflective delay line configuration composed by single phase unidirectional transducers (SPUDTs) and three shorted reflectors was fabricated on YZ LiNbO₃ piezoelectric substrate as the sensor element. A thin fluoroalcoholpolysiloxane (SXFA) film acted as the sensitive interface deposited onto the SAW propagation path between the second and last reflectors of the SAW device. The first reflector was used for the temperature compensation utilizing the difference method. The adsorption between the SXFA and OC molecules modulates the SAW propagation, especially for the time delay of the SAW, hence, the phase shifts of the reflection peaks from the corresponding reflectors can be used to characterize the target OC. Prior to the sensor fabrication, the coupling of modes (COM) and perturbation theory were utilized to predict the SAW device performance and the gas adsorption. Referring to a frequency-modulated continuous wave (FMCW)-based reader unit, the developed SAW chemical sensor was wirelessly characterized in gas exposure experiments for dimethylmethylphosphonate (DMMP) detection. Sensor performance parameters such as phase sensitivity, repeatability, linearity, and temperature compensation were evaluated experimentally. Full article

(This article belongs to the Section Chemical Sensors)

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22 pages, 10002 KiB

Open AccessArticle

Passive Sensor Integration for Vehicle Self-Localization in Urban Traffic Environment

by Yanlei Gu^*

, Li-Ta Hsu and Shunsuke Kamijo

Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan

Sensors 2015, 15(12), 30199-30220; https://doi.org/10.3390/s151229795 - 3 Dec 2015

Cited by 48 | Viewed by 10209

Abstract

This research proposes an accurate vehicular positioning system which can achieve lane-level performance in urban canyons. Multiple passive sensors, which include Global Navigation Satellite System (GNSS) receivers, onboard cameras and inertial sensors, are integrated in the proposed system. As the main source for [...] Read more.

This research proposes an accurate vehicular positioning system which can achieve lane-level performance in urban canyons. Multiple passive sensors, which include Global Navigation Satellite System (GNSS) receivers, onboard cameras and inertial sensors, are integrated in the proposed system. As the main source for the localization, the GNSS technique suffers from Non-Line-Of-Sight (NLOS) propagation and multipath effects in urban canyons. This paper proposes to employ a novel GNSS positioning technique in the integration. The employed GNSS technique reduces the multipath and NLOS effects by using the 3D building map. In addition, the inertial sensor can describe the vehicle motion, but has a drift problem as time increases. This paper develops vision-based lane detection, which is firstly used for controlling the drift of the inertial sensor. Moreover, the lane keeping and changing behaviors are extracted from the lane detection function, and further reduce the lateral positioning error in the proposed localization system. We evaluate the integrated localization system in the challenging city urban scenario. The experiments demonstrate the proposed method has sub-meter accuracy with respect to mean positioning error. Full article

(This article belongs to the Special Issue Sensors in New Road Vehicles)

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19 pages, 1269 KiB

Open AccessArticle

An Adaptive Channel Access Method for Dynamic Super Dense Wireless Sensor Networks

by Chunyang Lei^1,*

, Hongxia Bie¹, Gengfa Fang² and Xuekun Zhang¹

¹ School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China

² Department of Engineering, Macquarie University, Sydney 2109, Australia

Sensors 2015, 15(12), 30221-30239; https://doi.org/10.3390/s151229800 - 3 Dec 2015

Cited by 6 | Viewed by 5549

Abstract

Super dense and distributed wireless sensor networks have become very popular with the development of small cell technology, Internet of Things (IoT), Machine-to-Machine (M2M) communications, Vehicular-to-Vehicular (V2V) communications and public safety networks. While densely deployed wireless networks provide one of the most important [...] Read more.

Super dense and distributed wireless sensor networks have become very popular with the development of small cell technology, Internet of Things (IoT), Machine-to-Machine (M2M) communications, Vehicular-to-Vehicular (V2V) communications and public safety networks. While densely deployed wireless networks provide one of the most important and sustainable solutions to improve the accuracy of sensing and spectral efficiency, a new channel access scheme needs to be designed to solve the channel congestion problem introduced by the high dynamics of competing nodes accessing the channel simultaneously. In this paper, we firstly analyzed the channel contention problem using a novel normalized channel contention analysis model which provides information on how to tune the contention window according to the state of channel contention. We then proposed an adaptive channel contention window tuning algorithm in which the contention window tuning rate is set dynamically based on the estimated channel contention level. Simulation results show that our proposed adaptive channel access algorithm based on fast contention window tuning can achieve more than 95 % of the theoretical optimal throughput and 0 . 97 of fairness index especially in dynamic and dense networks. Full article

(This article belongs to the Section Sensor Networks)

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21 pages, 3101 KiB

Open AccessArticle

Tracking Multiple Video Targets with an Improved GM-PHD Tracker

by Xiaolong Zhou^1,2

, Hui Yu³

, Honghai Liu^2,* and Youfu Li⁴

¹ College of Computer Science and Technology, Zhejiang University of Technology, Hangzhou 310023, China

² School of Computing, University of Portsmouth, Portsmouth PO1 3HE, UK

³ School of Creative Technologies, University of Portsmouth, Portsmouth PO1 2DJ, UK

⁴ Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong, China

Sensors 2015, 15(12), 30240-30260; https://doi.org/10.3390/s151229794 - 3 Dec 2015

Cited by 28 | Viewed by 7057

Abstract

Tracking multiple moving targets from a video plays an important role in many vision-based robotic applications. In this paper, we propose an improved Gaussian mixture probability hypothesis density (GM-PHD) tracker with weight penalization to effectively and accurately track multiple moving targets from a [...] Read more.

Tracking multiple moving targets from a video plays an important role in many vision-based robotic applications. In this paper, we propose an improved Gaussian mixture probability hypothesis density (GM-PHD) tracker with weight penalization to effectively and accurately track multiple moving targets from a video. First, an entropy-based birth intensity estimation method is incorporated to eliminate the false positives caused by noisy video data. Then, a weight-penalized method with multi-feature fusion is proposed to accurately track the targets in close movement. For targets without occlusion, a weight matrix that contains all updated weights between the predicted target states and the measurements is constructed, and a simple, but effective method based on total weight and predicted target state is proposed to search the ambiguous weights in the weight matrix. The ambiguous weights are then penalized according to the fused target features that include spatial-colour appearance, histogram of oriented gradient and target area and further re-normalized to form a new weight matrix. With this new weight matrix, the tracker can correctly track the targets in close movement without occlusion. For targets with occlusion, a robust game-theoretical method is used. Finally, the experiments conducted on various video scenarios validate the effectiveness of the proposed penalization method and show the superior performance of our tracker over the state of the art. Full article

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

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9 pages, 3004 KiB

Open AccessArticle

Camera Calibration for Water-Biota Research: The Projected Area of Vegetation

by Rene Wackrow^*, Edgar Ferreira, Jim Chandler

and Koji Shiono

School of Civil and Building Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK

Sensors 2015, 15(12), 30261-30269; https://doi.org/10.3390/s151229798 - 3 Dec 2015

Cited by 6 | Viewed by 6222

Abstract

Imaging systems have an indisputable role in revealing vegetation posture under diverse flow conditions, image sequences being generated with off the shelf digital cameras. Such sensors are cheap but introduce a range of distortion effects, a trait only marginally tackled in hydraulic studies [...] Read more.

Imaging systems have an indisputable role in revealing vegetation posture under diverse flow conditions, image sequences being generated with off the shelf digital cameras. Such sensors are cheap but introduce a range of distortion effects, a trait only marginally tackled in hydraulic studies focusing on water-vegetation dependencies. This paper aims to bridge this gap by presenting a simple calibration method to remove both camera lens distortion and refractive effects of water. The effectiveness of the method is illustrated using the variable projected area, computed for both simple and complex shaped objects. Results demonstrate the significance of correcting images using a combined lens distortion and refraction model, prior to determining projected areas and further data analysis. Use of this technique is expected to increase data reliability for future work on vegetated channels. Full article

(This article belongs to the Special Issue Sensors and Techniques for 3D Object Modeling in Underwater Environments)

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23 pages, 7473 KiB

Open AccessArticle

Sensing Home: A Cost-Effective Design for Smart Home via Heterogeneous Wireless Networks

by Xiaohu Fan^1,*, Hao Huang^2,*, Shipeng Qi¹, Xincheng Luo¹, Jing Zeng¹, Qubo Xie¹ and Changsheng Xie^3,*

¹ School of Computer Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China

² School of Software Engineering, Huazhong University of Science and Technology, Wuhan 430074, China

³ Wuhan National Laboratory for Optoelectronics, No. 1037 Luoyu Road, Wuhan 430074, China

Sensors 2015, 15(12), 30270-30292; https://doi.org/10.3390/s151229797 - 3 Dec 2015

Cited by 13 | Viewed by 12147

Abstract

The aging population has inspired the marketing of advanced real time devices for home health care, more and more wearable devices and mobile applications, which have emerged in this field. However, to properly collect behavior information, accurately recognize human activities, and deploy the [...] Read more.

The aging population has inspired the marketing of advanced real time devices for home health care, more and more wearable devices and mobile applications, which have emerged in this field. However, to properly collect behavior information, accurately recognize human activities, and deploy the whole system in a real living environment is a challenging task. In this paper, we propose a feasible wireless-based solution to deploy a data collection scheme, activity recognition model, feedback control and mobile integration via heterogeneous networks. We compared and found a suitable algorithm that can be run on cost-efficient embedded devices. Specifically, we use the Super Set Transformation method to map the raw data into a sparse binary matrix. Furthermore, designed front-end devices of low power consumption gather the living data of the habitant via ZigBee to reduce the burden of wiring work. Finally, we evaluated our approach and show it can achieve a theoretical time-slice accuracy of 98%. The mapping solution we propose is compatible with more wearable devices and mobile apps. Full article

(This article belongs to the Special Issue Mobile Sensor Computing: Theory and Applications)

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18 pages, 5125 KiB

Open AccessArticle

Microelectromechanical Resonant Accelerometer Designed with a High Sensitivity

by Jing Zhang, Yan Su^†, Qin Shi^† and An-Ping Qiu^*

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

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 30293-30310; https://doi.org/10.3390/s151229803 - 3 Dec 2015

Cited by 46 | Viewed by 7374

Abstract

This paper describes the design and experimental evaluation of a silicon micro-machined resonant accelerometer (SMRA). This type of accelerometer works on the principle that a proof mass under acceleration applies force to two double-ended tuning fork (DETF) resonators, and the frequency output of [...] Read more.

This paper describes the design and experimental evaluation of a silicon micro-machined resonant accelerometer (SMRA). This type of accelerometer works on the principle that a proof mass under acceleration applies force to two double-ended tuning fork (DETF) resonators, and the frequency output of two DETFs exhibits a differential shift. The dies of an SMRA are fabricated using silicon-on-insulator (SOI) processing and wafer-level vacuum packaging. This research aims to design a high-sensitivity SMRA because a high sensitivity allows for the acceleration signal to be easily demodulated by frequency counting techniques and decreases the noise level. This study applies the energy-consumed concept and the Nelder-Mead algorithm in the SMRA to address the design issues and further increase its sensitivity. Using this novel method, the sensitivity of the SMRA has been increased by 66.1%, which attributes to both the re-designed DETF and the reduced energy loss on the micro-lever. The results of both the closed-form and finite-element analyses are described and are in agreement with one another. A resonant frequency of approximately 22 kHz, a frequency sensitivity of over 250 Hz per g, a one-hour bias stability of 55 μg, a bias repeatability (1σ) of 48 μg and the bias-instability of 4.8 μg have been achieved. Full article

(This article belongs to the Section Physical Sensors)

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8 pages, 6919 KiB

Open AccessArticle

Ultra-Compact 100 × 100 μm² Footprint Hybrid Device with Spin-Valve Nanosensors

by Diana C. Leitao^1,2,*

, Paulo Coelho¹, Jerome Borme³

, Simon Knudde^1,2, Susana Cardoso^1,2

and Paulo P. Freitas^1,3

¹ INESC-MN - Instituto de Engenharia de Sistemas e Computadores - Microsistemas e Nanotecnologias and IN - Institute of Nanoscience and Nanotechnology, Rua Alves Redol 9, Lisboa 1000-029, Portugal

² Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, Lisboa 1000, Portugal

³ INL - International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga, 4715 Braga, Portugal

Sensors 2015, 15(12), 30311-30318; https://doi.org/10.3390/s151229809 - 4 Dec 2015

Cited by 14 | Viewed by 8049

Abstract

Magnetic field mapping with micrometric spatial resolution and high sensitivity is a challenging application, and the technological solutions are usually based on large area devices integrating discrete magnetic flux guide elements. In this work we demonstrate a high performance hybrid device with improved [...] Read more.

Magnetic field mapping with micrometric spatial resolution and high sensitivity is a challenging application, and the technological solutions are usually based on large area devices integrating discrete magnetic flux guide elements. In this work we demonstrate a high performance hybrid device with improved field sensitivity levels and small footprint, consisting of a ultra-compact 2D design where nanometric spin valve sensors are inserted within the gap of thin-film magnetic flux concentrators. Pole-sensor distances down to 400 nm are demonstrated using nanofabrication techniques combined with an optimized liftoff process. These 100 × 100 μm 2 pixel sensors can be integrated in modular devices for surface mapping without moving parts. Full article

(This article belongs to the Special Issue Magnetoresistive Sensors under Extreme Conditions)

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21 pages, 2331 KiB

Open AccessArticle

Towards a Decentralized Magnetic Indoor Positioning System

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 2015, 15(12), 30319-30339; https://doi.org/10.3390/s151229799 - 4 Dec 2015

Cited by 26 | Viewed by 8222

Abstract

Decentralized magnetic indoor localization is a sophisticated method for processing sampled magnetic data directly on a mobile station (MS), thereby decreasing or even avoiding the need for communication with the base station. In contrast to central-oriented positioning systems, which transmit raw data to [...] Read more.

Decentralized magnetic indoor localization is a sophisticated method for processing sampled magnetic data directly on a mobile station (MS), thereby decreasing or even avoiding the need for communication with the base station. In contrast to central-oriented positioning systems, which transmit raw data to a base station, decentralized indoor localization pushes application-level knowledge into the MS. A decentralized position solution has thus a strong feasibility to increase energy efficiency and to prolong the lifetime of the MS. In this article, we present a complete architecture and an implementation for a decentralized positioning system. Furthermore, we introduce a technique for the synchronization of the observed magnetic field on the MS with the artificially-generated magnetic field from the coils. Based on real-time clocks (RTCs) and a preemptive operating system, this method allows a stand-alone control of the coils and a proper assignment of the measured magnetic fields on the MS. A stand-alone control and synchronization of the coils and the MS have an exceptional potential to implement a positioning system without the need for wired or wireless communication and enable a deployment of applications for rescue scenarios, like localization of miners or firefighters. Full article

(This article belongs to the Special Issue Sensors for Indoor Mapping and Navigation)

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11 pages, 1286 KiB

Open AccessArticle

Identification of Buried Objects in GPR Using Amplitude Modulated Signals Extracted from Multiresolution Monogenic Signal Analysis

by Lihong Qiao^1,2

, Yao Qin^1,2,*, Xiaozhen Ren^1,2 and Qifu Wang³

¹ College of Information Science and Engineering, Henan University of Technology, Zhengzhou 450001, China

² Key Laboratory of Grain Information Processing and Control, Henan University of Technology, Ministry of Education, Zhengzhou 450001, China

³ Henan Academy of Science, Applied Physics Institute Co., Ltd, Zhengzhou 450001, China

Sensors 2015, 15(12), 30340-30350; https://doi.org/10.3390/s151229801 - 4 Dec 2015

Cited by 40 | Viewed by 7948

Abstract

It is necessary to detect the target reflections in ground penetrating radar (GPR) images, so that surface metal targets can be identified successfully. In order to accurately locate buried metal objects, a novel method called the Multiresolution Monogenic Signal Analysis (MMSA) system is [...] Read more.

It is necessary to detect the target reflections in ground penetrating radar (GPR) images, so that surface metal targets can be identified successfully. In order to accurately locate buried metal objects, a novel method called the Multiresolution Monogenic Signal Analysis (MMSA) system is applied in ground penetrating radar (GPR) images. This process includes four steps. First the image is decomposed by the MMSA to extract the amplitude component of the B-scan image. The amplitude component enhances the target reflection and suppresses the direct wave and reflective wave to a large extent. Then we use the region of interest extraction method to locate the genuine target reflections from spurious reflections by calculating the normalized variance of the amplitude component. To find the apexes of the targets, a Hough transform is used in the restricted area. Finally, we estimate the horizontal and vertical position of the target. In terms of buried object detection, the proposed system exhibits promising performance, as shown in the experimental results. Full article

(This article belongs to the Section Remote Sensors)

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34 pages, 8419 KiB

Open AccessArticle

Underwater Photogrammetry and Object Modeling: A Case Study of Xlendi Wreck in Malta

by Pierre Drap^1,*,†

, Djamal Merad^1,†, Bilal Hijazi^1,†, Lamia Gaoua^1,†, Mohamad Motasem Nawaf^1,†, Mauro Saccone^1,†, Bertrand Chemisky^2,†, Julien Seinturier^2,†, Jean-Christophe Sourisseau^3,†

, Timmy Gambin^4,† and Filipe Castro^5,†

¹ Aix Marseille Université, CNRS, ENSAM, Université De Toulon, LSIS UMR 7296,13397 Marseille, France

² COMEX, COmpanie Maritime d’EXpertise 36 boulevard des Océans, 13009 Marseille, France

³ Aix Marseille Université, CNRS, Ministère de la Culture et de la Communication, CCJ UMR 7299, 13094 Aix En Provence, France

⁴ Archaeology Centre (Car Park 6), University of Malta, Msida MSD 2080, Malta

⁵ Ship Reconstruction Laboratory 4352 TAMU, Texas A & M University, College Station, TX 77843, USA

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 30351-30384; https://doi.org/10.3390/s151229802 - 4 Dec 2015

Cited by 69 | Viewed by 14198

Abstract

In this paper we present a photogrammetry-based approach for deep-sea underwater surveys conducted from a submarine and guided by knowledge-representation combined with a logical approach (ontology). Two major issues are discussed in this paper. The first concerns deep-sea surveys using photogrammetry from a [...] Read more.

In this paper we present a photogrammetry-based approach for deep-sea underwater surveys conducted from a submarine and guided by knowledge-representation combined with a logical approach (ontology). Two major issues are discussed in this paper. The first concerns deep-sea surveys using photogrammetry from a submarine. Here the goal was to obtain a set of images that completely covered the selected site. Subsequently and based on these images, a low-resolution 3D model is obtained in real-time, followed by a very high-resolution model produced back in the laboratory. The second issue involves the extraction of known artefacts present on the site. This aspect of the research is based on an a priori representation of the knowledge involved using systematic reasoning. Two parallel processes were developed to represent the photogrammetric process used for surveying as well as for identifying archaeological artefacts visible on the sea floor. Mapping involved the use of the CIDOC-CRM system (International Committee for Documentation (CIDOC)—Conceptual Reference Model)—This is a system that has been previously utilised to in the heritage sector and is largely available to the established scientific community. The proposed theoretical representation is based on procedural attachment; moreover, a strong link is maintained between the ontological description of the modelled concepts and the Java programming language which permitted 3D structure estimation and modelling based on a set of oriented images. A very recently discovered shipwreck acted as a testing ground for this project; the Xelendi Phoenician shipwreck, found off the Maltese coast, is probably the oldest known shipwreck in the western Mediterranean. The approach presented in this paper was developed in the scope of the GROPLAN project (Généralisation du Relevé, avec Ontologies et Photogrammétrie, pour l'Archéologie Navale et Sous-marine). Financed by the French National Research Agency (ANR) for four years, this project associates two French research laboratories, an industrial partner, the University of Malta, and Texas A & M University. Full article

(This article belongs to the Special Issue Sensors and Techniques for 3D Object Modeling in Underwater Environments)

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18 pages, 2772 KiB

Open AccessArticle

Multi-Target Tracking Based on Multi-Bernoulli Filter with Amplitude for Unknown Clutter Rate

by Changshun Yuan, Jun Wang^*, Peng Lei, Yanxian Bi and Zhongsheng Sun

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

Sensors 2015, 15(12), 30385-30402; https://doi.org/10.3390/s151229804 - 4 Dec 2015

Cited by 11 | Viewed by 6023

Abstract

Knowledge of the clutter rate is of critical importance in multi-target Bayesian tracking. However, estimating the clutter rate is a difficult problem in practice. In this paper, an improved multi-Bernoulli filter based on random finite sets for multi-target Bayesian tracking accommodating non-linear dynamic [...] Read more.

Knowledge of the clutter rate is of critical importance in multi-target Bayesian tracking. However, estimating the clutter rate is a difficult problem in practice. In this paper, an improved multi-Bernoulli filter based on random finite sets for multi-target Bayesian tracking accommodating non-linear dynamic and measurement models, as well as unknown clutter rate, is proposed for radar sensors. The proposed filter incorporates the amplitude information into the state and measurement spaces to improve discrimination between actual targets and clutters, while adaptively generating the new-born object random finite sets using the measurements to eliminate reliance on prior random finite sets. A sequential Monte-Carlo implementation of the proposed filter is presented, and simulations are used to demonstrate the proposed filter’s improvements in estimation accuracy of the target number and corresponding multi-target states, as well as the clutter rate. Full article

(This article belongs to the Section Remote Sensors)

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16 pages, 7091 KiB

Open AccessArticle

A Novel Method for Precise Onboard Real-Time Orbit Determination with a Standalone GPS Receiver

by Fuhong Wang^1,2, Xuewen Gong^1,2,*, Jizhang Sang^1,2 and Xiaohong Zhang^1,2

¹ School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China

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

Sensors 2015, 15(12), 30403-30418; https://doi.org/10.3390/s151229805 - 4 Dec 2015

Cited by 52 | Viewed by 8119

Abstract

Satellite remote sensing systems require accurate, autonomous and real-time orbit determinations (RTOD) for geo-referencing. Onboard Global Positioning System (GPS) has widely been used to undertake such tasks. In this paper, a novel RTOD method achieving decimeter precision using GPS carrier phases, required by [...] Read more.

Satellite remote sensing systems require accurate, autonomous and real-time orbit determinations (RTOD) for geo-referencing. Onboard Global Positioning System (GPS) has widely been used to undertake such tasks. In this paper, a novel RTOD method achieving decimeter precision using GPS carrier phases, required by China’s HY2A and ZY3 missions, is presented. A key to the algorithm success is the introduction of a new parameter, termed pseudo-ambiguity. This parameter combines the phase ambiguity, the orbit, and clock offset errors of the GPS broadcast ephemeris together to absorb a large part of the combined error. Based on the analysis of the characteristics of the orbit and clock offset errors, the pseudo-ambiguity can be modeled as a random walk, and estimated in an extended Kalman filter. Experiments of processing real data from HY2A and ZY3, simulating onboard operational scenarios of these two missions, are performed using the developed software SATODS. Results have demonstrated that the position and velocity accuracy (3D RMS) of 0.2–0.4 m and 0.2–0.4 mm/s, respectively, are achieved using dual-frequency carrier phases for HY2A, and slightly worse results for ZY3. These results show it is feasible to obtain orbit accuracy at decimeter level of 3–5 dm for position and 0.3–0.5 mm/s for velocity with this RTOD method. Full article

(This article belongs to the Special Issue Sensor Innovations for Spacecraft Guidance, Navigation, and Control)

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10 pages, 823 KiB

Open AccessArticle

GNSS Positioning by CORS and EGM2008 in Jilin Province, China

by Qiong Wu¹, Jingyu Kang¹, Shuwen Li², Jianing Zhen¹ and Hongqing Li^1,*

¹ College of Geo-exploration Science and Technology, Jilin University, Changchun 130026, China

² Jinan Institute of Survey and Investigation, Jinan 250013, China

Sensors 2015, 15(12), 30419-30428; https://doi.org/10.3390/s151229806 - 4 Dec 2015

Cited by 4 | Viewed by 7257

Abstract

The Continuously Operating Reference Station (CORS) technique has been widely applied in land resource management, surveying, mapping, deformation monitoring, precise navigation, etc. This article analyzed the positioning method using EGM2008 and CORS of Jilin Province, China. The vertical transformation of EGM2008 from WGS84 [...] Read more.

The Continuously Operating Reference Station (CORS) technique has been widely applied in land resource management, surveying, mapping, deformation monitoring, precise navigation, etc. This article analyzed the positioning method using EGM2008 and CORS of Jilin Province, China. The vertical transformation of EGM2008 from WGS84 to China’s CGCS2000 datum and the horizontal coordinate transformation from CGCS2000 to a triangulation coordinate system were discussed. The results indicated that a local geoid with respect to CGCS2000 can be transferred from EGM2008 with the same accuracy, and the geoid correction between CGCS2000 and WGS84 varied from 0.023 m to 0.111 m. The coordinate transformation method based on the curve surface approximation method indicated that the theoretical error was less than 0.09 m in the grid within 10° longitudinal and 5° latitudinal, and less than 0.3 m in large area and 0.1 m in small area in field validation. The method proposed in this article expanded the positioning result and its application for JLCORS and other CORS with local datum. Full article

(This article belongs to the Section Physical Sensors)

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14 pages, 1343 KiB

Open AccessArticle

Antibody Microarray for E. coli O157:H7 and Shiga Toxin in Microtiter Plates

by Andrew G. Gehring^*, Jeffrey D. Brewster, Yiping He, Peter L. Irwin, George C. Paoli, Tawana Simons, Shu-I Tu and Joseph Uknalis

Molecular Characterization of Foodborne Pathogens Research Unit, United States Department of Agriculture-Northeast Area, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, USA

Sensors 2015, 15(12), 30429-30442; https://doi.org/10.3390/s151229807 - 4 Dec 2015

Cited by 7 | Viewed by 6366

Abstract

Antibody microarray is a powerful analytical technique because of its inherent ability to simultaneously discriminate and measure numerous analytes, therefore making the technique conducive to both the multiplexed detection and identification of bacterial analytes (i.e., whole cells, as well as associated [...] Read more.

Antibody microarray is a powerful analytical technique because of its inherent ability to simultaneously discriminate and measure numerous analytes, therefore making the technique conducive to both the multiplexed detection and identification of bacterial analytes (i.e., whole cells, as well as associated metabolites and/or toxins). We developed a sandwich fluorescent immunoassay combined with a high-throughput, multiwell plate microarray detection format. Inexpensive polystyrene plates were employed containing passively adsorbed, array-printed capture antibodies. During sample reaction, centrifugation was the only strategy found to significantly improve capture, and hence detection, of bacteria (pathogenic Escherichia coli O157:H7) to planar capture surfaces containing printed antibodies. Whereas several other sample incubation techniques (e.g., static vs. agitation) had minimal effect. Immobilized bacteria were labeled with a red-orange-fluorescent dye (Alexa Fluor 555) conjugated antibody to allow for quantitative detection of the captured bacteria with a laser scanner. Shiga toxin 1 (Stx1) could be simultaneously detected along with the cells, but none of the agitation techniques employed during incubation improved detection of the relatively small biomolecule. Under optimal conditions, the assay had demonstrated limits of detection of ~5.8 × 10⁵ cells/mL and 110 ng/mL for E. coli O157:H7 and Stx1, respectively, in a ~75 min total assay time. Full article

(This article belongs to the Special Issue Sensors for Food Safety and Quality)

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14 pages, 4249 KiB

Open AccessArticle

Colloidal Stability and Magnetic Field-Induced Ordering of Magnetorheological Fluids Studied with a Quartz Crystal Microbalance

by Jaime Rodriguez-López¹, Pedro Castro^1,*, Juan De Vicente^2,†

, Diethelm Johannsmann^3,†, Luis Elvira^1,†

, Jose R. Morillas^2,† and Francisco Montero de Espinosa^1,†

¹ Institute of Physical and Information Technologies, CSIC, C/Serrano, 144, Madrid 28006, Spain

² Department of Applied Physics, Faculty of Sciences, University of Granada, c/Fuentenueva s/n, Granada 18071, Spain

³ Institute of Physical Chemistry, Clausthal University of Technology, Arnold-Sommerfeld-Str. 4, Clausthal Zellerfeld D-38678, Germany

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 30443-30456; https://doi.org/10.3390/s151229808 - 4 Dec 2015

Cited by 6 | Viewed by 5871

Abstract

This work proposes the use of quartz crystal microbalances (QCMs) as a method to analyze and characterize magnetorheological (MR) fluids. QCM devices are sensitive to changes in mass, surface interactions, and viscoelastic properties of the medium contacting its surface. These features make the [...] Read more.

This work proposes the use of quartz crystal microbalances (QCMs) as a method to analyze and characterize magnetorheological (MR) fluids. QCM devices are sensitive to changes in mass, surface interactions, and viscoelastic properties of the medium contacting its surface. These features make the QCM suitable to study MR fluids and their response to variable environmental conditions. MR fluids change their structure and viscoelastic properties under the action of an external magnetic field, this change being determined by the particle volume fraction, the magnetic field strength, and the presence of thixotropic agents among other factors. In this work, the measurement of the resonance parameters (resonance frequency and dissipation factor) of a QCM are used to analyze the behavior of MR fluids in static conditions (that is, in the absence of external mechanical stresses). The influence of sedimentation under gravity and the application of magnetic fields on the shifts of resonance frequency and dissipation factor were measured and discussed in the frame of the coupled resonance produced by particles touching the QCM surface. Furthermore, the MR-fluid/QCM system has a great potential for the study of high-frequency contact mechanics because the translational and rotational stiffness of the link between the surface and the particles can be tuned by the magnetic field. Full article

(This article belongs to the Section Physical Sensors)

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12 pages, 1707 KiB

Open AccessArticle

Modulation of Intracellular Quantum Dot to Fluorescent Protein Förster Resonance Energy Transfer via Customized Ligands and Spatial Control of Donor–Acceptor Assembly

by Lauren D. Field¹, Scott A. Walper¹, Kimihiro Susumu², Eunkeu Oh³, Igor L. Medintz¹ and James B. Delehanty^1,*

¹ Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, 4555 Overlook Ave, S.W., Washington, DC 20375, USA

² Sotera Defense Solutions, Inc., 7230 Lee DeForest Drive, Columbia, MD 21046, USA

³ Optical Sciences Division, Code 5600 U.S. Naval Research Laboratory, Washington, DC 20375, USA

Sensors 2015, 15(12), 30457-30468; https://doi.org/10.3390/s151229810 - 4 Dec 2015

Cited by 12 | Viewed by 6842

Abstract

Understanding how to controllably modulate the efficiency of energy transfer in Förster resonance energy transfer (FRET)-based assemblies is critical to their implementation as sensing modalities. This is particularly true for sensing assemblies that are to be used as the basis for real time [...] Read more.

Understanding how to controllably modulate the efficiency of energy transfer in Förster resonance energy transfer (FRET)-based assemblies is critical to their implementation as sensing modalities. This is particularly true for sensing assemblies that are to be used as the basis for real time intracellular sensing of intracellular processes and events. We use a quantum dot (QD) donor -mCherry acceptor platform that is engineered to self-assemble in situ wherein the protein acceptor is expressed via transient transfection and the QD donor is microinjected into the cell. QD-protein assembly is driven by metal-affinity interactions where a terminal polyhistidine tag on the protein binds to the QD surface. Using this system, we show the ability to modulate the efficiency of the donor–acceptor energy transfer process by controllably altering either the ligand coating on the QD surface or the precise location where the QD-protein assembly process occurs. Intracellularly, a short, zwitterionic ligand mediates more efficient FRET relative to longer ligand species that are based on the solubilizing polymer, poly(ethylene glycol). We further show that a greater FRET efficiency is achieved when the QD-protein assembly occurs free in the cytosol compared to when the mCherry acceptor is expressed tethered to the inner leaflet of the plasma membrane. In the latter case, the lower FRET efficiency is likely attributable to a lower expression level of the mCherry acceptor at the membrane combined with steric hindrance. Our work points to some of the design considerations that one must be mindful of when developing FRET-based sensing schemes for use in intracellular sensing. Full article

(This article belongs to the Special Issue FRET Biosensors)

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18 pages, 2741 KiB

Open AccessArticle

An Accurate and Generic Testing Approach to Vehicle Stability Parameters Based on GPS and INS

by Zhibin Miao^1,2,*, Hongtian Zhang^1,2,† and Jinzhu Zhang^2,†

¹ College of Power and Energy Engineering, Harbin Engineering University, Harbin 150001, China

² Heilongjiang Institute of Technology, Harbin 150050, China

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 30469-30486; https://doi.org/10.3390/s151229812 - 4 Dec 2015

Cited by 6 | Viewed by 8210

Abstract

With the development of the vehicle industry, controlling stability has become more and more important. Techniques of evaluating vehicle stability are in high demand. As a common method, usually GPS sensors and INS sensors are applied to measure vehicle stability parameters by fusing [...] Read more.

With the development of the vehicle industry, controlling stability has become more and more important. Techniques of evaluating vehicle stability are in high demand. As a common method, usually GPS sensors and INS sensors are applied to measure vehicle stability parameters by fusing data from the two system sensors. Although prior model parameters should be recognized in a Kalman filter, it is usually used to fuse data from multi-sensors. In this paper, a robust, intelligent and precise method to the measurement of vehicle stability is proposed. First, a fuzzy interpolation method is proposed, along with a four-wheel vehicle dynamic model. Second, a two-stage Kalman filter, which fuses the data from GPS and INS, is established. Next, this approach is applied to a case study vehicle to measure yaw rate and sideslip angle. The results show the advantages of the approach. Finally, a simulation and real experiment is made to verify the advantages of this approach. The experimental results showed the merits of this method for measuring vehicle stability, and the approach can meet the design requirements of a vehicle stability controller. Full article

(This article belongs to the Special Issue Sensors in New Road Vehicles)

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17 pages, 671 KiB

Open AccessReview

Ionic Liquid-Based Optical and Electrochemical Carbon Dioxide Sensors

by Kamalakanta Behera¹, Shubha Pandey², Anu Kadyan¹ and Siddharth Pandey^1,*

¹ Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India

² Department of Science and Technology, Ministry of Science and Technology, Technology Bhawan, New Mehrauli Road, New Delhi 110016, India

Sensors 2015, 15(12), 30487-30503; https://doi.org/10.3390/s151229813 - 4 Dec 2015

Cited by 72 | Viewed by 11191

Abstract

Due to their unusual physicochemical properties (e.g., high thermal stability, low volatility, high intrinsic conductivity, wide electrochemical windows and good solvating ability), ionic liquids have shown immense application potential in many research areas. Applications of ionic liquid in developing various sensors, especially for [...] Read more.

Due to their unusual physicochemical properties (e.g., high thermal stability, low volatility, high intrinsic conductivity, wide electrochemical windows and good solvating ability), ionic liquids have shown immense application potential in many research areas. Applications of ionic liquid in developing various sensors, especially for the sensing of biomolecules, such as nucleic acids, proteins and enzymes, gas sensing and sensing of various important ions, among other chemosensing platforms, are currently being explored by researchers worldwide. The use of ionic liquids for the detection of carbon dioxide (CO₂) gas is currently a major topic of research due to the associated importance of this gas with daily human life. This review focuses on the application of ionic liquids in optical and electrochemical CO₂ sensors. The design, mechanism, sensitivity and detection limit of each type of sensor are highlighted in this review. Full article

(This article belongs to the Special Issue Ionic Liquids)

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21 pages, 774 KiB

Open AccessReview

Graphene Hybrid Materials in Gas Sensing Applications

by Usman Latif¹ and Franz L. Dickert^2,*

¹ COMSATS Institute of Information Technology, Department of Chemistry, Tobe Camp, University Road, 22060 Abbottabad, Pakistan

² Department of Analytical Chemistry, University of Vienna, Währinger Str. 38, A-1090 Vienna, Austria

Sensors 2015, 15(12), 30504-30524; https://doi.org/10.3390/s151229814 - 4 Dec 2015

Cited by 116 | Viewed by 12673

Abstract

Graphene, a two dimensional structure of carbon atoms, has been widely used as a material for gas sensing applications because of its large surface area, excellent conductivity, and ease of functionalization. This article reviews the most recent advances in graphene hybrid materials developed [...] Read more.

Graphene, a two dimensional structure of carbon atoms, has been widely used as a material for gas sensing applications because of its large surface area, excellent conductivity, and ease of functionalization. This article reviews the most recent advances in graphene hybrid materials developed for gas sensing applications. In this review, synthetic approaches to fabricate graphene sensors, the nano structures of hybrid materials, and their sensing mechanism are presented. Future perspectives of this rapidly growing field are also discussed. Full article

(This article belongs to the Special Issue Gas Sensors—Designs and Applications)

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14 pages, 7200 KiB

Open AccessArticle

Seasonal Hydrological Loading in Southern Tibet Detected by Joint Analysis of GPS and GRACE

by Rong Zou^1,2, Qi Wang^1,*, Jeffrey T. Freymueller³, Markku Poutanen², Xuelian Cao¹, Caihong Zhang⁴, Shaomin Yang⁴ and Ping He¹

¹ Hubei Subsurface Multi-Scale Imaging Key Laboratory, Institute of Geophysics & Geomatics, China University of Geosciences (Wuhan), Wuhan 430074, China

² Finnish Geospatial Research Institute FGI, Geodeetinrinne 2, Masala 02430, Finland

³ Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775, USA

⁴ Institute of seismology, China Earthquake Administration & Hubei Earthquake Administration, Wuhan 430071, China

Sensors 2015, 15(12), 30525-30538; https://doi.org/10.3390/s151229815 - 4 Dec 2015

Cited by 32 | Viewed by 6637

Abstract

In southern Tibet, ongoing vertical and horizontal motions due to the collision between India and Eurasia are monitored by large numbers of global positioning system (GPS) continuous and campaign sites installed in the past decade. Displacements measured by GPS usually include tectonic deformation [...] Read more.

In southern Tibet, ongoing vertical and horizontal motions due to the collision between India and Eurasia are monitored by large numbers of global positioning system (GPS) continuous and campaign sites installed in the past decade. Displacements measured by GPS usually include tectonic deformation as well as non-tectonic, time-dependent signals. To estimate the regional long-term tectonic deformation using GPS more precisely, seasonal elastic deformation signals associated with surface loading must be removed from the observations. In this study, we focus on seasonal variation in vertical and horizontal motions of southern Tibet by performing a joint analysis of GRACE (Gravity Recovery and Climate Experiment) and GPS data, not only using continuous sites but also GPS campaign-mode sites. We found that the GPS-observed and GRACE-modeled seasonal oscillations are in good agreements, and a seasonal displacement model demonstrates that the main reason for seasonal variations in southern Tibet is from the summer monsoon and its precipitation. The biggest loading appears from July to August in the summer season. Vertical deformations observed by GPS and modeled by GRACE are two to three times larger than horizontal oscillations, and the north components demonstrate larger amplitudes than the east components. We corrected the GPS position time series using the GRACE-modeled seasonal variations, which gives significant reductions in the misfit and weighted root-mean-squares (WRMS). Misfit ( χ 2 divided by degree of freedom) reductions for campaign sites range between 20% and 56% for the vertical component, and are much smaller for the horizontal components. Moreover, time series of continuous GPS (cGPS) sites near the 2015 Nepal earthquakes must be corrected using appropriate models of seasonal loading for analyzing postseismic deformation to avoid biasing estimates of the postseismic relaxation. Full article

(This article belongs to the Section Remote Sensors)

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6 pages, 676 KiB

Open AccessArticle

Single ZnO Nanowire-Based Gas Sensors to Detect Low Concentrations of Hydrogen

by Marlene N. Cardoza-Contreras^1,*

, José M. Romo-Herrera^1,†, Luis A. Ríos^2,†, R. García-Gutiérrez^3,†, T. A. Zepeda^1,† and Oscar E. Contreras¹

¹ Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Baja California 22800, Mexico

² Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California 22860, Mexico

³ Departamento de Investigación en Física, Universidad de Sonora, Hermosillo 83000, Mexico

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 30539-30544; https://doi.org/10.3390/s151229816 - 4 Dec 2015

Cited by 31 | Viewed by 7629

Abstract

Low concentrations of hazardous gases are difficult to detect with common gas sensors. Using semiconductor nanostructures as a sensor element is an alternative. Single ZnO nanowire gas sensor devices were fabricated by manipulation and connection of a single nanowire into a four-electrode aluminum [...] Read more.

Low concentrations of hazardous gases are difficult to detect with common gas sensors. Using semiconductor nanostructures as a sensor element is an alternative. Single ZnO nanowire gas sensor devices were fabricated by manipulation and connection of a single nanowire into a four-electrode aluminum probe in situ in a dual-beam scanning electron microscope-focused ion beam with a manipulator and a gas injection system in/column. The electrical response of the manufactured devices shows response times up to 29 s for a 121 ppm of H₂ pulse, with a variation in the nanowire resistance appreciable at room temperature and at 373.15 K of approximately 8% and 14% respectively, showing that ZnO nanowires are good candidates to detect low concentrations of H₂. Full article

(This article belongs to the Special Issue Gas Sensors—Designs and Applications)

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26 pages, 2103 KiB

Open AccessArticle

Performance Evaluation of Localization Accuracy for a Log-Normal Shadow Fading Wireless Sensor Network under Physical Barrier Attacks

by Ahmed Abdulqader Hussein^1,2,*, Tharek A. Rahman¹ and Chee Yen Leow¹

¹ Wireless Communication Centre (WCC), Faculty of Electrical Engineering, Universiti Teknologi Malaysia, UTM Skudai, Johor 81310, Malaysia

² University of Technology, Baghdad 10066, Iraq

Sensors 2015, 15(12), 30545-30570; https://doi.org/10.3390/s151229817 - 4 Dec 2015

Cited by 17 | Viewed by 6688

Abstract

Localization is an apparent aspect of a wireless sensor network, which is the focus of much interesting research. One of the severe conditions that needs to be taken into consideration is localizing a mobile target through a dispersed sensor network in the presence [...] Read more.

Localization is an apparent aspect of a wireless sensor network, which is the focus of much interesting research. One of the severe conditions that needs to be taken into consideration is localizing a mobile target through a dispersed sensor network in the presence of physical barrier attacks. These attacks confuse the localization process and cause location estimation errors. Range-based methods, like the received signal strength indication (RSSI), face the major influence of this kind of attack. This paper proposes a solution based on a combination of multi-frequency multi-power localization (C-MFMPL) and step function multi-frequency multi-power localization (SF-MFMPL), including the fingerprint matching technique and lateration, to provide a robust and accurate localization technique. In addition, this paper proposes a grid coloring algorithm to detect the signal hole map in the network, which refers to the attack-prone regions, in order to carry out corrective actions. The simulation results show the enhancement and robustness of RSS localization performance in the face of log normal shadow fading effects, besides the presence of physical barrier attacks, through detecting, filtering and eliminating the effect of these attacks. Full article

(This article belongs to the Section Sensor Networks)

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13 pages, 9195 KiB

Open AccessArticle

Estimation of Human Arm Joints Using Two Wireless Sensors in Robotic Rehabilitation Tasks

by Arturo Bertomeu-Motos^*, Luis D. Lledó, Jorge A. Díez, Jose M. Catalan, Santiago Ezquerro, Francisco J. Badesa

and Nicolas Garcia-Aracil

Neuro-Bioengineering Research Group, Miguel Hernandez University, Avda. de la Universidad W/N, 03202 Elche, Spain

Sensors 2015, 15(12), 30571-30583; https://doi.org/10.3390/s151229818 - 4 Dec 2015

Cited by 30 | Viewed by 9640

Abstract

This paper presents a novel kinematic reconstruction of the human arm chain with five degrees of freedom and the estimation of the shoulder location during rehabilitation therapy assisted by end-effector robotic devices. This algorithm is based on the pseudoinverse of the Jacobian through [...] Read more.

This paper presents a novel kinematic reconstruction of the human arm chain with five degrees of freedom and the estimation of the shoulder location during rehabilitation therapy assisted by end-effector robotic devices. This algorithm is based on the pseudoinverse of the Jacobian through the acceleration of the upper arm, measured using an accelerometer, and the orientation of the shoulder, estimated with a magnetic angular rate and gravity (MARG) device. The results show a high accuracy in terms of arm joints and shoulder movement with respect to the real arm measured through an optoelectronic system. Furthermore, the range of motion (ROM) of 50 healthy subjects is studied from two different trials, one trying to avoid shoulder movements and the second one forcing them. Moreover, the shoulder movement in the second trial is also estimated accurately. Besides the fact that the posture of the patient can be corrected during the exercise, the therapist could use the presented algorithm as an objective assessment tool. In conclusion, the joints’ estimation enables a better adjustment of the therapy, taking into account the needs of the patient, and consequently, the arm motion improves faster. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Spain 2015)

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33 pages, 3847 KiB

Open AccessArticle

An On-Demand Emergency Packet Transmission Scheme for Wireless Body Area Networks

by Moshaddique Al Ameen and Choong Seon Hong^*

Department of Computer Science and Engineering, College of Electronics & Information, Kyung Hee University, Yongin-si, Gyeongggi-do 17104, Korea

Sensors 2015, 15(12), 30584-30616; https://doi.org/10.3390/s151229819 - 4 Dec 2015

Cited by 16 | Viewed by 6811

Abstract

The rapid developments of sensor devices that can actively monitor human activities have given rise to a new field called wireless body area network (BAN). A BAN can manage devices in, on and around the human body. Major requirements of such a network [...] Read more.

The rapid developments of sensor devices that can actively monitor human activities have given rise to a new field called wireless body area network (BAN). A BAN can manage devices in, on and around the human body. Major requirements of such a network are energy efficiency, long lifetime, low delay, security, etc. Traffic in a BAN can be scheduled (normal) or event-driven (emergency). Traditional media access control (MAC) protocols use duty cycling to improve performance. A sleep-wake up cycle is employed to save energy. However, this mechanism lacks features to handle emergency traffic in a prompt and immediate manner. To deliver an emergency packet, a node has to wait until the receiver is awake. It also suffers from overheads, such as idle listening, overhearing and control packet handshakes. An external radio-triggered wake up mechanism is proposed to handle prompt communication. It can reduce the overheads and improve the performance through an on-demand scheme. In this work, we present a simple-to-implement on-demand packet transmission scheme by taking into considerations the requirements of a BAN. The major concern is handling the event-based emergency traffic. The performance analysis of the proposed scheme is presented. The results showed significant improvements in the overall performance of a BAN compared to state-of-the-art protocols in terms of energy consumption, delay and lifetime. Full article

(This article belongs to the Section Sensor Networks)

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19 pages, 1410 KiB

Open AccessArticle

A Coral Reef Algorithm Based on Learning Automata for the Coverage Control Problem of Heterogeneous Directional Sensor Networks

by Ming Li^1,2,3,*, Chunyan Miao^3,† and Cyril Leung^4,†

¹ Detection and Control of Integrated Systems Engineering Laboratory in Chongqing Technology and Business University, Chongqing 400067, China

² School of Computer Science and Information Engineering, Chongqing Technology and Business University, Chongqing 400067, China

³ School of Computer Engineering, Nanyang Technological University, Nanyang Avenue 639798, Singapore

⁴ Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 30617-30635; https://doi.org/10.3390/s151229820 - 4 Dec 2015

Cited by 24 | Viewed by 5322

Abstract

Coverage control is one of the most fundamental issues in directional sensor networks. In this paper, the coverage optimization problem in a directional sensor network is formulated as a multi-objective optimization problem. It takes into account the coverage rate of the network, the [...] Read more.

Coverage control is one of the most fundamental issues in directional sensor networks. In this paper, the coverage optimization problem in a directional sensor network is formulated as a multi-objective optimization problem. It takes into account the coverage rate of the network, the number of working sensor nodes and the connectivity of the network. The coverage problem considered in this paper is characterized by the geographical irregularity of the sensed events and heterogeneity of the sensor nodes in terms of sensing radius, field of angle and communication radius. To solve this multi-objective problem, we introduce a learning automata-based coral reef algorithm for adaptive parameter selection and use a novel Tchebycheff decomposition method to decompose the multi-objective problem into a single-objective problem. Simulation results show the consistent superiority of the proposed algorithm over alternative approaches. Full article

(This article belongs to the Section Sensor Networks)

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17 pages, 541 KiB

Open AccessArticle

User-Independent Motion State Recognition Using Smartphone Sensors

by Fuqiang Gu^1,*

, Allison Kealy¹, Kourosh Khoshelham¹

and Jianga Shang²

¹ Department of Infrastructure Engineering, University of Melbourne, Parkville, Victoria 3010, Australia

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

Sensors 2015, 15(12), 30636-30652; https://doi.org/10.3390/s151229821 - 4 Dec 2015

Cited by 45 | Viewed by 9563

Abstract

The recognition of locomotion activities (e.g., walking, running, still) is important for a wide range of applications like indoor positioning, navigation, location-based services, and health monitoring. Recently, there has been a growing interest in activity recognition using accelerometer data. However, when utilizing only [...] Read more.

The recognition of locomotion activities (e.g., walking, running, still) is important for a wide range of applications like indoor positioning, navigation, location-based services, and health monitoring. Recently, there has been a growing interest in activity recognition using accelerometer data. However, when utilizing only acceleration-based features, it is difficult to differentiate varying vertical motion states from horizontal motion states especially when conducting user-independent classification. In this paper, we also make use of the newly emerging barometer built in modern smartphones, and propose a novel feature called pressure derivative from the barometer readings for user motion state recognition, which is proven to be effective for distinguishing vertical motion states and does not depend on specific users’ data. Seven types of motion states are defined and six commonly-used classifiers are compared. In addition, we utilize the motion state history and the characteristics of people’s motion to improve the classification accuracies of those classifiers. Experimental results show that by using the historical information and human’s motion characteristics, we can achieve user-independent motion state classification with an accuracy of up to 90.7%. In addition, we analyze the influence of the window size and smartphone pose on the accuracy. Full article

(This article belongs to the Special Issue Sensors for Indoor Mapping and Navigation)

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30 pages, 1547 KiB

Open AccessArticle

A Review of Intelligent Driving Style Analysis Systems and Related Artificial Intelligence Algorithms

by Gys Albertus Marthinus Meiring^† and Hermanus Carel Myburgh^*,†

¹ Department of Electrical, Electronic and Computer Engineering, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa

^† The authors contributed equally to this work.

Sensors 2015, 15(12), 30653-30682; https://doi.org/10.3390/s151229822 - 4 Dec 2015

Cited by 226 | Viewed by 23924

Abstract

In this paper the various driving style analysis solutions are investigated. An in-depth investigation is performed to identify the relevant machine learning and artificial intelligence algorithms utilised in current driver behaviour and driving style analysis systems. This review therefore serves as a trove [...] Read more.

In this paper the various driving style analysis solutions are investigated. An in-depth investigation is performed to identify the relevant machine learning and artificial intelligence algorithms utilised in current driver behaviour and driving style analysis systems. This review therefore serves as a trove of information, and will inform the specialist and the student regarding the current state of the art in driver style analysis systems, the application of these systems and the underlying artificial intelligence algorithms applied to these applications. The aim of the investigation is to evaluate the possibilities for unique driver identification utilizing the approaches identified in other driver behaviour studies. It was found that Fuzzy Logic inference systems, Hidden Markov Models and Support Vector Machines consist of promising capabilities to address unique driver identification algorithms if model complexity can be reduced. Full article

(This article belongs to the Section Physical Sensors)

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10 pages, 1909 KiB

Open AccessArticle

Evaluation of Chemical Interactions between Small Molecules in the Gas Phase Using Chemical Force Microscopy

by Jieun Lee^1,2, Soomi Ju¹, In Tae Kim¹, Sun-Hwa Jung³, Sun-Joon Min⁴

, Chulki Kim⁵, Sang Jun Sim² and Sang Kyung Kim^1,*

¹ Center for Biomicrosystems, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Korea

² Department of Chemical and Biological Engineering, Korea University, 5-ga Annam-dong, Seongbuk-gu, Seoul 136-713, Korea

³ Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology(KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Korea

⁴ Department of Applied Chemistry, Hanyang University, Sangnok-gu, Ansan, Gyeonggi-do 15588, Korea

⁵ Center for Sensor System Research, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Korea

Sensors 2015, 15(12), 30683-30692; https://doi.org/10.3390/s151229823 - 4 Dec 2015

Cited by 4 | Viewed by 6400

Abstract

Chemical force microscopy analyzes the interactions between various chemical/biochemical moieties in situ. In this work we examined force-distance curves and lateral force to measure the interaction between modified AFM tips and differently functionalized molecular monolayers. Especially for the measurements in gas phase, [...] Read more.

Chemical force microscopy analyzes the interactions between various chemical/biochemical moieties in situ. In this work we examined force-distance curves and lateral force to measure the interaction between modified AFM tips and differently functionalized molecular monolayers. Especially for the measurements in gas phase, we investigated the effect of humidity on the analysis of force-distance curves and the images in lateral force mode. Flat chemical patterns composed of different functional groups were made through micro-contact printing and lateral force mode provided more resolved analysis of the chemical patterns. From the images of 1-octadecanethiol/11-mercapto-1-undecanoic acid patterns, the amine group functionalized tip brought out higher contrast of the patterns than an intact silicon nitride tip owing to the additional chemical interaction between carboxyl and amine groups. For more complex chemical interactions, relative chemical affinities toward specific peptides were assessed on the pattern of 1-octadecanethiol/phenyl-terminated alkanethiol. The lateral image of chemical force microscopy reflected specific preference of a peptide to phenyl group as well as the hydrophobic interaction. Full article

(This article belongs to the Section Chemical Sensors)

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11 pages, 2189 KiB

Open AccessArticle

Corrosion Resistant FBG-Based Quasi-Distributed Sensor for Crude Oil Tank Dynamic Temperature Profile Monitoring

by Rogério Da Silva Marques^1,2, Adilson Ribeiro Prado^2,3, Paulo Fernando Da Costa Antunes⁴, Paulo Sérgio De Brito André⁵, Moisés R. N. Ribeiro²

, Anselmo Frizera-Neto²

and Maria José Pontes^2,*

¹ Federal Institute of Espírito Santo, Av. Filogônio Peixoto 2220, Bairro Aviso, Linhares 29901-291, Brazil

² Federal University of Espírito Santo, Department of Electrical Engineering, Av. Fernando Ferrari, 514, Goiabeiras, Vitória 29075-910, Brazil

³ Federal Institute of Espírito Santo, Rodovia ES 010, km 6.5-Manguinhos, Serra 29173-087, Brazil

⁴ Instituto de Telecomunicações, I3N and Physics Department, University of Aveiro, Campus Universitário de Santiago, Aveiro 3810-193, Portugal

⁵ Instituto de Telecomunicações and Department of Electrical and Computer Engineering, Superior Technical Institute , University of Lisbon, Av. Rovisco Pais, Lisbon 1049-001, Portugal

Sensors 2015, 15(12), 30693-30703; https://doi.org/10.3390/s151229811 - 5 Dec 2015

Cited by 66 | Viewed by 7417

Abstract

This article presents a corrosion resistant, maneuverable, and intrinsically safe fiber Bragg grating (FBG)-based temperature optical sensor. Temperature monitoring is a critical activity for the oil and gas industry. It typically involves acquiring the desired parameters in a hazardous and corrosive environment. The [...] Read more.

This article presents a corrosion resistant, maneuverable, and intrinsically safe fiber Bragg grating (FBG)-based temperature optical sensor. Temperature monitoring is a critical activity for the oil and gas industry. It typically involves acquiring the desired parameters in a hazardous and corrosive environment. The use of polytetrafluoroethylene (PTFE) was proposed as a means of simultaneously isolating the optical fiber from the corrosive environment and avoiding undesirable mechanical tensions on the FBGs. The presented sensor head is based on multiple FBGs inscribed in a lengthy single mode fiber. The sensor presents an average thermal sensitivity of 8.82 ± 0.09 pm/°C, resulting in a typical temperature resolution of ~0.1 °C and an average time constant value of 6.25 ± 0.08 s. Corrosion and degradation resistance were verified by infrared spectroscopy and scanning electron microscopy during 90 days exposure to high salinity crude oil samples. The developed sensor was tested in a field pilot test, mimicking the operation of an inland crude tank, demonstrating its abilities to dynamically monitor temperature profile. Full article

(This article belongs to the Section Physical Sensors)

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12 pages, 1815 KiB

Open AccessArticle

Preconcentration and Separation of Mixed-Species Samples Near a Nano-Junction in a Convergent Microchannel

by Ping-Hsien Chiu¹, Chen-Hsun Weng²

and Ruey-Jen Yang^1,*

¹ Department of Engineering Science, National Cheng Kung University, Tainan 70101, Taiwan

² Medical Device Innovation Center, National Cheng Kung University, Tainan 70101, Taiwan

Sensors 2015, 15(12), 30704-30715; https://doi.org/10.3390/s151229824 - 5 Dec 2015

Cited by 7 | Viewed by 5676

Abstract

A fluidic microchip incorporating a convergent microchannel and a Nafion-nanoporous membrane is proposed for the preconcentration and separation of multi-species samples on a single platform. In the device, sample preconcentration is achieved by means of the ion concentration polarization effect induced at the [...] Read more.

A fluidic microchip incorporating a convergent microchannel and a Nafion-nanoporous membrane is proposed for the preconcentration and separation of multi-species samples on a single platform. In the device, sample preconcentration is achieved by means of the ion concentration polarization effect induced at the micro/nano interface under the application of an external electric field, while species separation is achieved by exploiting the different electrophoretic mobilities of the sample components. The experimental results show that the device is capable of detecting C-reactive protein (CRP) with an initial concentration as low as 9.50 × 10⁻⁶ mg/L given a sufficient preconcentration time and driving voltage. In addition, it is shown that a mixed-species sample consisting of three negatively-charged components (bovine serum albumin (BSA), tetramethylrhodamine(TAMRA) isothiocyanate-Dextran and fluorescent polymer beads) can be separated and preconcentrated within 20 min given a driving voltage of 100 V across 1 cm microchannel in length. In general, the present results confirm the feasibility of the device for the immunoassay or detection of various multi-species samples under low concentration in the biochemical and biomedical fields. The novel device can therefore improve the detection limit of traditional medical facilities. Full article

(This article belongs to the Section Physical Sensors)

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20 pages, 9872 KiB

Open AccessArticle

The Bubble Box: Towards an Automated Visual Sensor for 3D Analysis and Characterization of Marine Gas Release Sites

by Anne Jordt^1,*, Claudius Zelenka², Jens Schneider Von Deimling¹, Reinhard Koch² and Kevin Köser¹

¹ GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel 24148, Germany

² Department of Computer Science, Kiel University, Kiel 24118, Germany

Sensors 2015, 15(12), 30716-30735; https://doi.org/10.3390/s151229825 - 5 Dec 2015

Cited by 18 | Viewed by 10003

Abstract

Several acoustic and optical techniques have been used for characterizing natural and anthropogenic gas leaks (carbon dioxide, methane) from the ocean floor. Here, single-camera based methods for bubble stream observation have become an important tool, as they help estimating flux and bubble sizes [...] Read more.

Several acoustic and optical techniques have been used for characterizing natural and anthropogenic gas leaks (carbon dioxide, methane) from the ocean floor. Here, single-camera based methods for bubble stream observation have become an important tool, as they help estimating flux and bubble sizes under certain assumptions. However, they record only a projection of a bubble into the camera and therefore cannot capture the full 3D shape, which is particularly important for larger, non-spherical bubbles. The unknown distance of the bubble to the camera (making it appear larger or smaller than expected) as well as refraction at the camera interface introduce extra uncertainties. In this article, we introduce our wide baseline stereo-camera deep-sea sensor bubble box that overcomes these limitations, as it observes bubbles from two orthogonal directions using calibrated cameras. Besides the setup and the hardware of the system, we discuss appropriate calibration and the different automated processing steps deblurring, detection, tracking, and 3D fitting that are crucial to arrive at a 3D ellipsoidal shape and rise speed of each bubble. The obtained values for single bubbles can be aggregated into statistical bubble size distributions or fluxes for extrapolation based on diffusion and dissolution models and large scale acoustic surveys. We demonstrate and evaluate the wide baseline stereo measurement model using a controlled test setup with ground truth information. Full article

(This article belongs to the Special Issue Sensors and Techniques for 3D Object Modeling in Underwater Environments)

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23 pages, 2890 KiB

Open AccessFeature PaperReview

Portable Nanoparticle-Based Sensors for Food Safety Assessment

by Gonca Bülbül¹, Akhtar Hayat² and Silvana Andreescu^1,*

¹ Department of Chemistry and Biomolecular Science, Clarkson University, Potsdam, NY 13699-5810, USA

² Interdisciplinary Research Centre in Biomedical Materials, COMSAT Institute of Information Technology (CIIT), Defence Road, Off Raiwind Road, Lahore 54000, Pakistan

Sensors 2015, 15(12), 30736-30758; https://doi.org/10.3390/s151229826 - 5 Dec 2015

Cited by 167 | Viewed by 18543

Abstract

The use of nanotechnology-derived products in the development of sensors and analytical measurement methodologies has increased significantly over the past decade. Nano-based sensing approaches include the use of nanoparticles (NPs) and nanostructures to enhance sensitivity and selectivity, design new detection schemes, improve sample [...] Read more.

The use of nanotechnology-derived products in the development of sensors and analytical measurement methodologies has increased significantly over the past decade. Nano-based sensing approaches include the use of nanoparticles (NPs) and nanostructures to enhance sensitivity and selectivity, design new detection schemes, improve sample preparation and increase portability. This review summarizes recent advancements in the design and development of NP-based sensors for assessing food safety. The most common types of NPs used to fabricate sensors for detection of food contaminants are discussed. Selected examples of NP-based detection schemes with colorimetric and electrochemical detection are provided with focus on sensors for the detection of chemical and biological contaminants including pesticides, heavy metals, bacterial pathogens and natural toxins. Current trends in the development of low-cost portable NP-based technology for rapid assessment of food safety as well as challenges for practical implementation and future research directions are discussed. Full article

(This article belongs to the Special Issue Sensors for Food Safety and Quality)

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25 pages, 2008 KiB

Open AccessArticle

A Hybrid Indoor Localization and Navigation System with Map Matching for Pedestrians Using Smartphones

by Qinglin Tian^1,*, Zoran Salcic², Kevin I-Kai Wang² and Yun Pan³

¹ College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China

² Department of Electrical and Computer Engineering, University of Auckland, Auckland 1010, New Zealand

³ Department of Information Science & Electronic Engineering, Zhejiang University, Hangzhou 310027, China

Sensors 2015, 15(12), 30759-30783; https://doi.org/10.3390/s151229827 - 5 Dec 2015

Cited by 42 | Viewed by 8631

Abstract

Pedestrian dead reckoning is a common technique applied in indoor inertial navigation systems that is able to provide accurate tracking performance within short distances. Sensor drift is the main bottleneck in extending the system to long-distance and long-term tracking. In this paper, a [...] Read more.

Pedestrian dead reckoning is a common technique applied in indoor inertial navigation systems that is able to provide accurate tracking performance within short distances. Sensor drift is the main bottleneck in extending the system to long-distance and long-term tracking. In this paper, a hybrid system integrating traditional pedestrian dead reckoning based on the use of inertial measurement units, short-range radio frequency systems and particle filter map matching is proposed. The system is a drift-free pedestrian navigation system where position error and sensor drift is regularly corrected and is able to provide long-term accurate and reliable tracking. Moreover, the whole system is implemented on a commercial off-the-shelf smartphone and achieves real-time positioning and tracking performance with satisfactory accuracy. Full article

(This article belongs to the Special Issue Sensors for Indoor Mapping and Navigation)

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26 pages, 15388 KiB

Open AccessArticle

Sinusoidal Wave Estimation Using Photogrammetry and Short Video Sequences

by Ewelina Rupnik^*, Josef Jansa and Norbert Pfeifer

Department of Geodesy and Geoinformation, Technische Universität Wien, Gusshausstrasse 27-29, Vienna 1040, Austria

Sensors 2015, 15(12), 30784-30809; https://doi.org/10.3390/s151229828 - 5 Dec 2015

Cited by 18 | Viewed by 9557

Abstract

The objective of the work is to model the shape of the sinusoidal shape of regular water waves generated in a laboratory flume. The waves are traveling in time and render a smooth surface, with no white caps or foam. Two methods are [...] Read more.

The objective of the work is to model the shape of the sinusoidal shape of regular water waves generated in a laboratory flume. The waves are traveling in time and render a smooth surface, with no white caps or foam. Two methods are proposed, treating the water as a diffuse and specular surface, respectively. In either case, the water is presumed to take the shape of a traveling sine wave, reducing the task of the 3D reconstruction to resolve the wave parameters. The first conceived method performs the modeling part purely in 3D space. Having triangulated the points in a separate phase via bundle adjustment, a sine wave is fitted into the data in a least squares manner. The second method presents a more complete approach for the entire calculation workflow beginning in the image space. The water is perceived as a specular surface, and the traveling specularities are the only observations visible to the cameras, observations that are notably single image. The depth ambiguity is removed given additional constraints encoded within the law of reflection and the modeled parametric surface. The observation and constraint equations compose a single system of equations that is solved with the method of least squares adjustment. The devised approaches are validated against the data coming from a capacitive level sensor and on physical targets floating on the surface. The outcomes agree to a high degree. Full article

(This article belongs to the Special Issue Sensors and Techniques for 3D Object Modeling in Underwater Environments)

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17 pages, 1168 KiB

Open AccessReview

Calibration Techniques for Accurate Measurements by Underwater Camera Systems

by Mark Shortis

School of Mathematical and Geospatial Sciences, RMIT University, GPO Box 2476, Melbourne 3001, Australia

Sensors 2015, 15(12), 30810-30826; https://doi.org/10.3390/s151229831 - 7 Dec 2015

Cited by 148 | Viewed by 12458

Abstract

Calibration of a camera system is essential to ensure that image measurements result in accurate estimates of locations and dimensions within the object space. In the underwater environment, the calibration must implicitly or explicitly model and compensate for the refractive effects of waterproof [...] Read more.

Calibration of a camera system is essential to ensure that image measurements result in accurate estimates of locations and dimensions within the object space. In the underwater environment, the calibration must implicitly or explicitly model and compensate for the refractive effects of waterproof housings and the water medium. This paper reviews the different approaches to the calibration of underwater camera systems in theoretical and practical terms. The accuracy, reliability, validation and stability of underwater camera system calibration are also discussed. Samples of results from published reports are provided to demonstrate the range of possible accuracies for the measurements produced by underwater camera systems. Full article

(This article belongs to the Special Issue Sensors and Techniques for 3D Object Modeling in Underwater Environments)

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12 pages, 1383 KiB

Open AccessArticle

Maximum-Likelihood Estimator of Clock Offset between Nanomachines in Bionanosensor Networks

by Lin Lin^1,*, Chengfeng Yang¹ and Maode Ma²

¹ School of Mechatronic Engineering and Automation, Shanghai University, Shanghai 200072, China

² School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798

Sensors 2015, 15(12), 30827-30838; https://doi.org/10.3390/s151229830 - 7 Dec 2015

Cited by 9 | Viewed by 4757

Abstract

Recent advances in nanotechnology, electronic technology and biology have enabled the development of bio-inspired nanoscale sensors. The cooperation among the bionanosensors in a network is envisioned to perform complex tasks. Clock synchronization is essential to establish diffusion-based distributed cooperation in the bionanosensor networks. [...] Read more.

Recent advances in nanotechnology, electronic technology and biology have enabled the development of bio-inspired nanoscale sensors. The cooperation among the bionanosensors in a network is envisioned to perform complex tasks. Clock synchronization is essential to establish diffusion-based distributed cooperation in the bionanosensor networks. This paper proposes a maximum-likelihood estimator of the clock offset for the clock synchronization among molecular bionanosensors. The unique properties of diffusion-based molecular communication are described. Based on the inverse Gaussian distribution of the molecular propagation delay, a two-way message exchange mechanism for clock synchronization is proposed. The maximum-likelihood estimator of the clock offset is derived. The convergence and the bias of the estimator are analyzed. The simulation results show that the proposed estimator is effective for the offset compensation required for clock synchronization. This work paves the way for the cooperation of nanomachines in diffusion-based bionanosensor networks. Full article

(This article belongs to the Section Sensor Networks)

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17 pages, 2368 KiB

Open AccessArticle

Labeled RFS-Based Track-Before-Detect for Multiple Maneuvering Targets in the Infrared Focal Plane Array

by Miao Li^*, Jun Li and Yiyu Zhou

College of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073, Hunan, P.R. China

Sensors 2015, 15(12), 30839-30855; https://doi.org/10.3390/s151229829 - 8 Dec 2015

Cited by 5 | Viewed by 5754

Abstract

The problem of jointly detecting and tracking multiple targets from the raw observations of an infrared focal plane array is a challenging task, especially for the case with uncertain target dynamics. In this paper a multi-model labeled multi-Bernoulli (MM-LMB) track-before-detect method is proposed [...] Read more.

The problem of jointly detecting and tracking multiple targets from the raw observations of an infrared focal plane array is a challenging task, especially for the case with uncertain target dynamics. In this paper a multi-model labeled multi-Bernoulli (MM-LMB) track-before-detect method is proposed within the labeled random finite sets (RFS) framework. The proposed track-before-detect method consists of two parts—MM-LMB filter and MM-LMB smoother. For the MM-LMB filter, original LMB filter is applied to track-before-detect based on target and measurement models, and is integrated with the interacting multiple models (IMM) approach to accommodate the uncertainty of target dynamics. For the MM-LMB smoother, taking advantage of the track labels and posterior model transition probability, the single-model single-target smoother is extended to a multi-model multi-target smoother. A Sequential Monte Carlo approach is also presented to implement the proposed method. Simulation results show the proposed method can effectively achieve tracking continuity for multiple maneuvering targets. In addition, compared with the forward filtering alone, our method is more robust due to its combination of forward filtering and backward smoothing. Full article

(This article belongs to the Special Issue Infrared and THz Sensing and Imaging)

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14 pages, 399 KiB

Open AccessArticle

DOA Estimation under Unknown Mutual Coupling and Multipath with Improved Effective Array Aperture

by Yuexian Wang^*, Matthew Trinkle and Brian W.-H. Ng

University of Adelaide Radar Research Centre, School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, SA 5005, Australia

Sensors 2015, 15(12), 30856-30869; https://doi.org/10.3390/s151229832 - 8 Dec 2015

Cited by 28 | Viewed by 5927

Abstract

Subspace-based high-resolution direction of arrival (DOA) estimation significantly deteriorates under array manifold perturbation and rank deficiency of the covariance matrix due to mutual coupling and multipath propagation, respectively. In this correspondence, the unknown mutual coupling can be circumvented by the proposed method without [...] Read more.

Subspace-based high-resolution direction of arrival (DOA) estimation significantly deteriorates under array manifold perturbation and rank deficiency of the covariance matrix due to mutual coupling and multipath propagation, respectively. In this correspondence, the unknown mutual coupling can be circumvented by the proposed method without any passive or active calibration process, and the DOA of the coherent signals can be accurately estimated accordingly. With a newly constructed matrix, the deficient rank can be restored, and the effective array aperture can be extended compared with conventional spatial smoothing. The proposed method achieves a good robustness and DOA estimation accuracy with unknown mutual coupling. The simulation results demonstrate the validity and efficiency of the proposed method. Full article

(This article belongs to the Section Physical Sensors)

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24 pages, 7097 KiB

Open AccessArticle

Development of a 3D Underground Cadastral System with Indoor Mapping for As-Built BIM: The Case Study of Gangnam Subway Station in Korea

by Sangmin Kim¹, Jeonghyun Kim¹, Jaehoon Jung^1,2 and Joon Heo^1,*

¹ School of Civil and Environmental Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Korea

² Department of Photogrammetry, University of Bonn, Nussallee 15, Bonn 53115, Germany

Sensors 2015, 15(12), 30870-30893; https://doi.org/10.3390/s151229833 - 9 Dec 2015

Cited by 30 | Viewed by 11392

Abstract

The cadastral system provides land ownership information by registering and representing land boundaries on a map. The current cadastral system in Korea, however, focuses mainly on the management of 2D land-surface boundaries. It is not yet possible to provide efficient or reliable land [...] Read more.

The cadastral system provides land ownership information by registering and representing land boundaries on a map. The current cadastral system in Korea, however, focuses mainly on the management of 2D land-surface boundaries. It is not yet possible to provide efficient or reliable land administration, as this 2D system cannot support or manage land information on 3D properties (including architectures and civil infrastructures) for both above-ground and underground facilities. A geometrical model of the 3D parcel, therefore, is required for registration of 3D properties. This paper, considering the role of the cadastral system, proposes a framework for a 3D underground cadastral system that can register various types of 3D underground properties using indoor mapping for as-built Building Information Modeling (BIM). The implementation consists of four phases: (1) geometric modeling of a real underground infrastructure using terrestrial laser scanning data; (2) implementation of as-built BIM based on geometric modeling results; (3) accuracy assessment for created as-built BIM using reference points acquired by total station; and (4) creation of three types of 3D underground cadastral map to represent underground properties. The experimental results, based on indoor mapping for as-built BIM, show that the proposed framework for a 3D underground cadastral system is able to register the rights, responsibilities, and restrictions corresponding to the 3D underground properties. In this way, clearly identifying the underground physical situation enables more reliable and effective decision-making in all aspects of the national land administration system. Full article

(This article belongs to the Special Issue Sensors for Indoor Mapping and Navigation)

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19 pages, 6660 KiB

Open AccessArticle

Development of a Scalable Testbed for Mobile Olfaction Verification

by Syed Muhammad Mamduh Syed Zakaria^1,2,3,*,†

, Retnam Visvanathan^1,2,†, Kamarulzaman Kamarudin^1,2,†, Ahmad Shakaff Ali Yeon^1,2,†, Ali Yeon Md. Shakaff^1,2,†, Ammar Zakaria^1,2,†

and Latifah Munirah Kamarudin^1,4,†

¹ Centre of Excellence for Advanced Sensor Technology (CEASTech), Universiti Malaysia Perlis, Pusat Pengajian Jejawi II, Taman Muhibbah, Arau, Perlis 02600, Malaysia

² School of Mechatronic Engineering, Universiti Malaysia Perlis, Pauh Putra Campus, Arau, Perlis 02600, Malaysia

³ School of Microelectronic Engineering, Universiti Malaysia Perlis, Pauh Putra Campus, Arau, Perlis 02600, Malaysia

⁴ School of Computer Engineering, Universiti Malaysia Perlis, Pauh Putra Campus, Arau, Perlis 02600, Malaysia

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 30894-30912; https://doi.org/10.3390/s151229834 - 9 Dec 2015

Cited by 9 | Viewed by 5527

Abstract

The lack of information on ground truth gas dispersion and experiment verification information has impeded the development of mobile olfaction systems, especially for real-world conditions. In this paper, an integrated testbed for mobile gas sensing experiments is presented. The integrated 3 m × [...] Read more.

The lack of information on ground truth gas dispersion and experiment verification information has impeded the development of mobile olfaction systems, especially for real-world conditions. In this paper, an integrated testbed for mobile gas sensing experiments is presented. The integrated 3 m × 6 m testbed was built to provide real-time ground truth information for mobile olfaction system development. The testbed consists of a 72-gas-sensor array, namely Large Gas Sensor Array (LGSA), a localization system based on cameras and a wireless communication backbone for robot communication and integration into the testbed system. Furthermore, the data collected from the testbed may be streamed into a simulation environment to expedite development. Calibration results using ethanol have shown that using a large number of gas sensor in the LGSA is feasible and can produce coherent signals when exposed to the same concentrations. The results have shown that the testbed was able to capture the time varying characteristics and the variability of gas plume in a 2 h experiment thus providing time dependent ground truth concentration maps. The authors have demonstrated the ability of the mobile olfaction testbed to monitor, verify and thus, provide insight to gas distribution mapping experiment. Full article

(This article belongs to the Section Chemical Sensors)

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14 pages, 4570 KiB

Open AccessArticle

An Intelligent Optical Dissolved Oxygen Measurement Method Based on a Fluorescent Quenching Mechanism

by Fengmei Li, Yaoguang Wei^*, Yingyi Chen, Daoliang Li and Xu Zhang

College of Information and Electrical Engineering, China Agricultural University, 17 Tsinghua East Road, Beijing 100083, China

Sensors 2015, 15(12), 30913-30926; https://doi.org/10.3390/s151229837 - 9 Dec 2015

Cited by 25 | Viewed by 9425

Abstract

Dissolved oxygen (DO) is a key factor that influences the healthy growth of fishes in aquaculture. The DO content changes with the aquatic environment and should therefore be monitored online. However, traditional measurement methods, such as iodometry and other chemical analysis methods, are [...] Read more.

Dissolved oxygen (DO) is a key factor that influences the healthy growth of fishes in aquaculture. The DO content changes with the aquatic environment and should therefore be monitored online. However, traditional measurement methods, such as iodometry and other chemical analysis methods, are not suitable for online monitoring. The Clark method is not stable enough for extended periods of monitoring. To solve these problems, this paper proposes an intelligent DO measurement method based on the fluorescence quenching mechanism. The measurement system is composed of fluorescent quenching detection, signal conditioning, intelligent processing, and power supply modules. The optical probe adopts the fluorescent quenching mechanism to detect the DO content and solves the problem, whereas traditional chemical methods are easily influenced by the environment. The optical probe contains a thermistor and dual excitation sources to isolate visible parasitic light and execute a compensation strategy. The intelligent processing module adopts the IEEE 1451.2 standard and realizes intelligent compensation. Experimental results show that the optical measurement method is stable, accurate, and suitable for online DO monitoring in aquaculture applications. Full article

(This article belongs to the Section Chemical Sensors)

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15 pages, 5467 KiB

Open AccessArticle

New Vehicle Detection Method with Aspect Ratio Estimation for Hypothesized Windows

by Jisu Kim¹, Jeonghyun Baek¹, Yongseo Park² and Euntai Kim^1,*

¹ The School of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749, Korea

² Department of Electrical Engineering, Gachon University, Seongnam 461-701, Korea

Sensors 2015, 15(12), 30927-30941; https://doi.org/10.3390/s151229838 - 9 Dec 2015

Cited by 5 | Viewed by 5744

Abstract

All kinds of vehicles have different ratios of width to height, which are called the aspect ratios. Most previous works, however, use a fixed aspect ratio for vehicle detection (VD). The use of a fixed vehicle aspect ratio for VD degrades the performance. [...] Read more.

All kinds of vehicles have different ratios of width to height, which are called the aspect ratios. Most previous works, however, use a fixed aspect ratio for vehicle detection (VD). The use of a fixed vehicle aspect ratio for VD degrades the performance. Thus, the estimation of a vehicle aspect ratio is an important part of robust VD. Taking this idea into account, a new on-road vehicle detection system is proposed in this paper. The proposed method estimates the aspect ratio of the hypothesized windows to improve the VD performance. Our proposed method uses an Aggregate Channel Feature (ACF) and a support vector machine (SVM) to verify the hypothesized windows with the estimated aspect ratio. The contribution of this paper is threefold. First, the estimation of vehicle aspect ratio is inserted between the HG (hypothesis generation) and the HV (hypothesis verification). Second, a simple HG method named a signed horizontal edge map is proposed to speed up VD. Third, a new measure is proposed to represent the overlapping ratio between the ground truth and the detection results. This new measure is used to show that the proposed method is better than previous works in terms of robust VD. Finally, the Pittsburgh dataset is used to verify the performance of the proposed method. Full article

(This article belongs to the Section Physical Sensors)

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22 pages, 6004 KiB

Open AccessArticle

PHACK: An Efficient Scheme for Selective Forwarding Attack Detection in WSNs

by Anfeng Liu¹

, Mianxiong Dong²

, Kaoru Ota²

and Jun Long^1,*

¹ School of Information Science and Engineering, Central South University, ChangSha 410083, China

² Department of Information and Electronic Engineering, Muroran Insitute of Technology, Hokkaido 050-8585, Japan

Sensors 2015, 15(12), 30942-30963; https://doi.org/10.3390/s151229835 - 9 Dec 2015

Cited by 39 | Viewed by 6212

Abstract

In this paper, a Per-Hop Acknowledgement (PHACK)-based scheme is proposed for each packet transmission to detect selective forwarding attacks. In our scheme, the sink and each node along the forwarding path generate an acknowledgement (ACK) message for each received packet to confirm the [...] Read more.

In this paper, a Per-Hop Acknowledgement (PHACK)-based scheme is proposed for each packet transmission to detect selective forwarding attacks. In our scheme, the sink and each node along the forwarding path generate an acknowledgement (ACK) message for each received packet to confirm the normal packet transmission. The scheme, in which each ACK is returned to the source node along a different routing path, can significantly increase the resilience against attacks because it prevents an attacker from compromising nodes in the return routing path, which can otherwise interrupt the return of nodes’ ACK packets. For this case, the PHACK scheme also has better potential to detect abnormal packet loss and identify suspect nodes as well as better resilience against attacks. Another pivotal issue is the network lifetime of the PHACK scheme, as it generates more acknowledgements than previous ACK-based schemes. We demonstrate that the network lifetime of the PHACK scheme is not lower than that of other ACK-based schemes because the scheme just increases the energy consumption in non-hotspot areas and does not increase the energy consumption in hotspot areas. Moreover, the PHACK scheme greatly simplifies the protocol and is easy to implement. Both theoretical and simulation results are given to demonstrate the effectiveness of the proposed scheme in terms of high detection probability and the ability to identify suspect nodes. Full article

(This article belongs to the Section Sensor Networks)

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17 pages, 1540 KiB

Open AccessArticle

Impact of Heterogeneity and Secrecy on theCapacity of Wireless Sensor Networks

by Qiuming Liu^1,2

, Li Yu^1,*, Zuhao Liu³ and Jun Zheng¹

¹ School of Electronic Information and Communications, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China

² Nanchang of Jiangxi University of Science and Technology, 1180 Shuanggang Road, Nanchang 330013, China

³ China Yangtze Power Co., Ltd., 1 Xibajianshe Road, Yichang 443002, China

Sensors 2015, 15(12), 30964-30980; https://doi.org/10.3390/s151229844 - 10 Dec 2015

Cited by 1 | Viewed by 4728

Abstract

This paper investigates the achievable secrecy throughput of an inhomogeneous wireless sensor network. We consider the impact of topology heterogeneity and the secrecy constraint on the throughput. For the topology heterogeneity, by virtue of percolation theory, a set of connected highways and information [...] Read more.

This paper investigates the achievable secrecy throughput of an inhomogeneous wireless sensor network. We consider the impact of topology heterogeneity and the secrecy constraint on the throughput. For the topology heterogeneity, by virtue of percolation theory, a set of connected highways and information pipelines is established; while for the secrecy constraint, the concept of secrecy zone is adopted to ensure secrecy transmission. The secrecy zone means there is no eavesdropper around the legitimate node. The results demonstrate that, if the eavesdropper’s intensity is λ_e= o log n - 3 δ - 4 δ - 2 , a per-node secrecy rate of Ω 1 n 1 - v ( 1 - v ) log n can be achieved on the highways, where δ is the exponent of heterogeneity, n and n v represent the number of nodes and clusters in the network, respectively. It is also shown that, with the density of the eavesdropper λ e = o log n Φ ̲ - 2 , the per-node secrecy rate of Ω Φ ̲ n can be obtained in the information pipelines, where Φ ̲ denotes the minimum node density in the network. Full article

(This article belongs to the Special Issue Security and Privacy in Sensor Networks)

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10 pages, 2949 KiB

Open AccessArticle

Multiple Temperature-Sensing Behavior of Green and Red Upconversion Emissions from Stark Sublevels of Er³⁺

by Baosheng Cao, Jinlei Wu, Xuehan Wang, Yangyang He, Zhiqing Feng and Bin Dong^*

School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600, China

Sensors 2015, 15(12), 30981-30990; https://doi.org/10.3390/s151229839 - 10 Dec 2015

Cited by 54 | Viewed by 6012

Abstract

Upconversion luminescence properties from the emissions of Stark sublevels of Er³⁺ were investigated in Er³⁺-Yb³⁺-Mo⁶⁺-codoped TiO₂ phosphors in this study. According to the energy levels split from Er³⁺, green and red emissions from [...] Read more.

Upconversion luminescence properties from the emissions of Stark sublevels of Er³⁺ were investigated in Er³⁺-Yb³⁺-Mo⁶⁺-codoped TiO₂ phosphors in this study. According to the energy levels split from Er³⁺, green and red emissions from the transitions of four coupled energy levels, ²H_11/2(I)/²H_11/2(II), ⁴S_3/2(I)/⁴S_3/2(II), ⁴F_9/2(I)/⁴F_9/2(II), and ²H_11/2(I) + ²H_11/2(II)/⁴S_3/2(I) + ⁴S_3/2(II), were observed under 976 nm laser diode excitation. By utilizing the fluorescence intensity ratio (FIR) technique, temperature-dependent upconversion emissions from these four coupled energy levels were analyzed at length. The optical temperature-sensing behaviors of sensing sensitivity, measurement error, and operating temperature for the four coupled energy levels are discussed, all of which are closely related to the energy gap of the coupled energy levels, FIR value, and luminescence intensity. Experimental results suggest that Er³⁺-Yb³⁺-Mo⁶⁺-codoped TiO₂ phosphor with four pairs of energy levels coupled by Stark sublevels provides a new and effective route to realize multiple optical temperature-sensing through a wide range of temperatures in an independent system. Full article

(This article belongs to the Section Physical Sensors)

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14 pages, 3180 KiB

Open AccessArticle

Model-Based Angular Scan Error Correction of an Electrothermally-Actuated MEMS Mirror

by Hao Zhang^1,3, Dacheng Xu^1,*, Xiaoyang Zhang², Qiao Chen³, Huikai Xie²

and Suiqiong Li¹

¹ School of Electronic and Information Engineering, Soochow University, Suzhou 215006, China

² Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida, FL 32611-6200, USA

³ Wuxi WiO Technology Co. Ltd, Wuxi 214000, China

Sensors 2015, 15(12), 30991-31004; https://doi.org/10.3390/s151229840 - 10 Dec 2015

Cited by 10 | Viewed by 6704

Abstract

In this paper, the actuation behavior of a two-axis electrothermal MEMS (Microelectromechanical Systems) mirror typically used in miniature optical scanning probes and optical switches is investigated. The MEMS mirror consists of four thermal bimorph actuators symmetrically located at the four sides of a [...] Read more.

In this paper, the actuation behavior of a two-axis electrothermal MEMS (Microelectromechanical Systems) mirror typically used in miniature optical scanning probes and optical switches is investigated. The MEMS mirror consists of four thermal bimorph actuators symmetrically located at the four sides of a central mirror plate. Experiments show that an actuation characteristics difference of as much as 4.0% exists among the four actuators due to process variations, which leads to an average angular scan error of 0.03°. A mathematical model between the actuator input voltage and the mirror-plate position has been developed to predict the actuation behavior of the mirror. It is a four-input, four-output model that takes into account the thermal-mechanical coupling and the differences among the four actuators; the vertical positions of the ends of the four actuators are also monitored. Based on this model, an open-loop control method is established to achieve accurate angular scanning. This model-based open loop control has been experimentally verified and is useful for the accurate control of the mirror. With this control method, the precise actuation of the mirror solely depends on the model prediction and does not need the real-time mirror position monitoring and feedback, greatly simplifying the MEMS control system. Full article

(This article belongs to the Section Physical Sensors)

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18 pages, 5666 KiB

Open AccessArticle

An Intelligent Weather Station

by Gonçalo Mestre^1,†, Antonio Ruano^2,3,*,†

, Helder Duarte^2,†, Sergio Silva^1,†, Hamid Khosravani², Shabnam Pesteh²

, Pedro M. Ferreira^4,†

and Ricardo Horta⁵

¹ EasySensing—Intelligent Systems, Centro Empresarial de Gambelas, Pav A5, Campus de Gambelas, University of Algarve, 8005-139 Faro, Portugal

² Faculty of Science and Technology, Campus de Gambelas, University of Algarve, 8005-139 Faro, Portugal

³ Centre for Intelligent Systems, IDMEC, Instituto Superior Técnico, 1049-001 Lisboa, Portugal

⁴ LaSIGE, Faculdade de Ciências, Universidade de Lisboa, Portugal

⁵ Rolear SA, 8001-906 Faro, Portugal

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 31005-31022; https://doi.org/10.3390/s151229841 - 10 Dec 2015

Cited by 45 | Viewed by 11675

Abstract

Accurate measurements of global solar radiation, atmospheric temperature and relative humidity, as well as the availability of the predictions of their evolution over time, are important for different areas of applications, such as agriculture, renewable energy and energy management, or thermal comfort in [...] Read more.

Accurate measurements of global solar radiation, atmospheric temperature and relative humidity, as well as the availability of the predictions of their evolution over time, are important for different areas of applications, such as agriculture, renewable energy and energy management, or thermal comfort in buildings. For this reason, an intelligent, light-weight, self-powered and portable sensor was developed, using a nearest-neighbors (NEN) algorithm and artificial neural network (ANN) models as the time-series predictor mechanisms. The hardware and software design of the implemented prototype are described, as well as the forecasting performance related to the three atmospheric variables, using both approaches, over a prediction horizon of 48-steps-ahead. Full article

(This article belongs to the Special Issue Towards Energy-Neutral WSN Architectures: Energy Harvesting and Other Enabling Technologies)

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13 pages, 6354 KiB

Open AccessArticle

An Integrated Instrumentation System for Velocity, Concentration and Mass Flow Rate Measurement of Solid Particles Based on Electrostatic and Capacitance Sensors

by Jian Li¹, Ming Kong², Chuanlong Xu^1,*, Shimin Wang¹ and Ying Fan³

¹ Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, China

² College of Metrology and Measurement Engineering, China Jiliang University, Hangzhou 310018, China

³ School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou 730050, China

Sensors 2015, 15(12), 31023-31035; https://doi.org/10.3390/s151229843 - 10 Dec 2015

Cited by 26 | Viewed by 7184

Abstract

The online and continuous measurement of velocity, concentration and mass flow rate of pneumatically conveyed solid particles for the high-efficiency utilization of energy and raw materials has become increasingly significant. In this paper, an integrated instrumentation system for the velocity, concentration and mass [...] Read more.

The online and continuous measurement of velocity, concentration and mass flow rate of pneumatically conveyed solid particles for the high-efficiency utilization of energy and raw materials has become increasingly significant. In this paper, an integrated instrumentation system for the velocity, concentration and mass flow rate measurement of dense phase pneumatically conveyed solid particles based on electrostatic and capacitance sensorsis developed. The electrostatic sensors are used for particle mean velocity measurement in combination with the cross-correlation technique, while the capacitance sensor with helical surface-plate electrodes, which has relatively homogeneous sensitivity distribution, is employed for the measurement of particle concentration and its capacitance is measured by an electrostatic-immune AC-based circuit. The solid mass flow rate can be further calculated from the measured velocity and concentration. The developed instrumentation system for velocity and concentration measurement is verified and calibrated on a pulley rig and through static experiments, respectively. Finally the system is evaluated with glass beads on a gravity-fed rig. The experimental results demonstrate that the system is capable of the accurate solid mass flow rate measurement, and the relative error is within −3%–8% for glass bead mass flow rates ranging from 0.13 kg/s to 0.9 kg/s. Full article

(This article belongs to the Section Physical Sensors)

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20 pages, 1537 KiB

Open AccessReview

Theory and Application of Magnetic Flux Leakage Pipeline Detection

by Yan Shi^1,*, Chao Zhang¹, Rui Li^1,2

, Maolin Cai¹ and Guanwei Jia¹

¹ School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China

² PetroChina Pipeline Company, Langfang 065000, China

Sensors 2015, 15(12), 31036-31055; https://doi.org/10.3390/s151229845 - 10 Dec 2015

Cited by 315 | Viewed by 24677

Abstract

Magnetic flux leakage (MFL) detection is one of the most popular methods of pipeline inspection. It is a nondestructive testing technique which uses magnetic sensitive sensors to detect the magnetic leakage field of defects on both the internal and external surfaces of pipelines. [...] Read more.

Magnetic flux leakage (MFL) detection is one of the most popular methods of pipeline inspection. It is a nondestructive testing technique which uses magnetic sensitive sensors to detect the magnetic leakage field of defects on both the internal and external surfaces of pipelines. This paper introduces the main principles, measurement and processing of MFL data. As the key point of a quantitative analysis of MFL detection, the identification of the leakage magnetic signal is also discussed. In addition, the advantages and disadvantages of different identification methods are analyzed. Then the paper briefly introduces the expert systems used. At the end of this paper, future developments in pipeline MFL detection are predicted. Full article

(This article belongs to the Section Physical Sensors)

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13 pages, 280 KiB

Open AccessArticle

Compressive Sensing Based Design of Sparse Tripole Arrays

by Matthew Hawes^1,*, Wei Liu²

and Lyudmila Mihaylova¹

¹ Department of Automatic Control and Systems Engineering, University of Sheffield, Sheffield S1 3JD, UK

² Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield S1 3JD, UK

Sensors 2015, 15(12), 31056-31068; https://doi.org/10.3390/s151229849 - 10 Dec 2015

Cited by 9 | Viewed by 5618

Abstract

This paper considers the problem of designing sparse linear tripole arrays. In such arrays at each antenna location there are three orthogonal dipoles, allowing full measurement of both the horizontal and vertical components of the received waveform. We formulate this problem from the [...] Read more.

This paper considers the problem of designing sparse linear tripole arrays. In such arrays at each antenna location there are three orthogonal dipoles, allowing full measurement of both the horizontal and vertical components of the received waveform. We formulate this problem from the viewpoint of Compressive Sensing (CS). However, unlike for isotropic array elements (single antenna), we now have three complex valued weight coefficients associated with each potential location (due to the three dipoles), which have to be simultaneously minimised. If this is not done, we may only set the weight coefficients of individual dipoles to be zero valued, rather than complete tripoles, meaning some dipoles may remain at each location. Therefore, the contributions of this paper are to formulate the design of sparse tripole arrays as an optimisation problem, and then we obtain a solution based on the minimisation of a modified l 1 norm or a series of iteratively solved reweighted minimisations, which ensure a truly sparse solution. Design examples are provided to verify the effectiveness of the proposed methods and show that a good approximation of a reference pattern can be achieved using fewer tripoles than a Uniform Linear Array (ULA) of equivalent length. Full article

(This article belongs to the Section Physical Sensors)

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14 pages, 216 KiB

Open AccessArticle

A New Missing Data Imputation Algorithm Applied to Electrical Data Loggers

by Concepción Crespo Turrado¹, Fernando Sánchez Lasheras^2,*

, José Luis Calvo-Rollé³

, Andrés José Piñón-Pazos³ and Francisco Javier De Cos Juez⁴

¹ Maintenance Department, University of Oviedo, San Francisco 3, Oviedo 33007, Spain

² Department of Construction and Manufacturing Engineering, University of Oviedo, Campus de Viesques, Gijón 33204, Spain

³ Departamento de Ingeniería Industrial, University of A Coruña, A Coruña 15405, Spain

⁴ Prospecting and Exploitation of Mines Department, University of Oviedo, Oviedo 33004, Spain

Sensors 2015, 15(12), 31069-31082; https://doi.org/10.3390/s151229842 - 10 Dec 2015

Cited by 31 | Viewed by 6141

Abstract

Nowadays, data collection is a key process in the study of electrical power networks when searching for harmonics and a lack of balance among phases. In this context, the lack of data of any of the main electrical variables (phase-to-neutral voltage, phase-to-phase voltage, [...] Read more.

Nowadays, data collection is a key process in the study of electrical power networks when searching for harmonics and a lack of balance among phases. In this context, the lack of data of any of the main electrical variables (phase-to-neutral voltage, phase-to-phase voltage, and current in each phase and power factor) adversely affects any time series study performed. When this occurs, a data imputation process must be accomplished in order to substitute the data that is missing for estimated values. This paper presents a novel missing data imputation method based on multivariate adaptive regression splines (MARS) and compares it with the well-known technique called multivariate imputation by chained equations (MICE). The results obtained demonstrate how the proposed method outperforms the MICE algorithm. Full article

(This article belongs to the Section Physical Sensors)

9 pages, 2298 KiB

Open AccessArticle

Disposable Non-Enzymatic Glucose Sensors Using Screen-Printed Nickel/Carbon Composites on Indium Tin Oxide Electrodes

by Won-Yong Jeon^1,†, Young-Bong Choi^2,† and Hyug-Han Kim^1,2,*

¹ Department of Nanobiomedical Sciences and BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Anseo-Dong, Cheonan, Chungnam 330-714, Korea

² Department of Chemistry, College of Natural Science, Dankook University, Anseo-Dong, Cheonan, Chungnam 330-714, Korea

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 31083-31091; https://doi.org/10.3390/s151229846 - 10 Dec 2015

Cited by 34 | Viewed by 8044

Abstract

Disposable screen-printed nickel/carbon composites on indium tin oxide (ITO) electrodes (DSPNCE) were developed for the detection of glucose without enzymes. The DSPNCE were prepared by screen-printing the ITO substrate with a 50 wt% nickel/carbon composite, followed by curing at 400 °C for 30 [...] Read more.

Disposable screen-printed nickel/carbon composites on indium tin oxide (ITO) electrodes (DSPNCE) were developed for the detection of glucose without enzymes. The DSPNCE were prepared by screen-printing the ITO substrate with a 50 wt% nickel/carbon composite, followed by curing at 400 °C for 30 min. The redox couple of Ni(OH)₂/NiOOH was deposited on the surface of the electrodes via cyclic voltammetry (CV), scanning from 0–1.5 V for 30 cycles in 0.1 M NaOH solution. The DSPNCE were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and electrochemical methods. The resulting electrical currents, measured by CV and chronoamperometry at 0.65 V vs. Ag/AgCl, showed a good linear response with glucose concentrations from 1.0–10 mM. Also, the prepared electrodes showed no interference from common physiologic interferents such as uric acid (UA) or ascorbic acid (AA). Therefore, this approach allowed the development of a simple, disposable glucose biosensor. Full article

(This article belongs to the Section Biosensors)

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16 pages, 5050 KiB

Open AccessArticle

Sensor-Aware Recognition and Tracking for Wide-Area Augmented Reality on Mobile Phones

by Jing Chen¹, Ruochen Cao^2,* and Yongtian Wang^1,2

¹ School of Optoelectronics, Beijing Institute of Technology, Beijing 100081, China

² School of Computer Science and Technology, Beijing Institute of Technology, Beijing 100081, China

Sensors 2015, 15(12), 31092-31107; https://doi.org/10.3390/s151229847 - 10 Dec 2015

Cited by 11 | Viewed by 6852

Abstract

Wide-area registration in outdoor environments on mobile phones is a challenging task in mobile augmented reality fields. We present a sensor-aware large-scale outdoor augmented reality system for recognition and tracking on mobile phones. GPS and gravity information is used to improve the VLAD [...] Read more.

Wide-area registration in outdoor environments on mobile phones is a challenging task in mobile augmented reality fields. We present a sensor-aware large-scale outdoor augmented reality system for recognition and tracking on mobile phones. GPS and gravity information is used to improve the VLAD performance for recognition. A kind of sensor-aware VLAD algorithm, which is self-adaptive to different scale scenes, is utilized to recognize complex scenes. Considering vision-based registration algorithms are too fragile and tend to drift, data coming from inertial sensors and vision are fused together by an extended Kalman filter (EKF) to achieve considerable improvements in tracking stability and robustness. Experimental results show that our method greatly enhances the recognition rate and eliminates the tracking jitters. Full article

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

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17 pages, 2605 KiB

Open AccessArticle

A Novel Energy-Aware Distributed Clustering Algorithm for Heterogeneous Wireless Sensor Networks in the Mobile Environment

by Ying Gao¹, Chris Hadri Wkram², Jiajie Duan³ and Jarong Chou^4,*

¹ College of Computer Science and Engineering, South China University of Technology, Guangzhou 510006, China

² Lawrence Berkeley National Laboratory, University of California, Oakland, CA 94612, USA

³ Yun Nan Electric Power Test & Research Institute Group CO., Kunming 650217, China

⁴ College of Engineering, Michigan State University, East Lansing, MI 48824, USA

Sensors 2015, 15(12), 31108-31124; https://doi.org/10.3390/s151229836 - 10 Dec 2015

Cited by 13 | Viewed by 6021

Abstract

In order to prolong the network lifetime, energy-efficient protocols adapted to the features of wireless sensor networks should be used. This paper explores in depth the nature of heterogeneous wireless sensor networks, and finally proposes an algorithm to address the problem of finding [...] Read more.

In order to prolong the network lifetime, energy-efficient protocols adapted to the features of wireless sensor networks should be used. This paper explores in depth the nature of heterogeneous wireless sensor networks, and finally proposes an algorithm to address the problem of finding an effective pathway for heterogeneous clustering energy. The proposed algorithm implements cluster head selection according to the degree of energy attenuation during the network’s running and the degree of candidate nodes’ effective coverage on the whole network, so as to obtain an even energy consumption over the whole network for the situation with high degree of coverage. Simulation results show that the proposed clustering protocol has better adaptability to heterogeneous environments than existing clustering algorithms in prolonging the network lifetime. Full article

(This article belongs to the Special Issue Mobile Sensor Computing: Theory and Applications)

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17 pages, 820 KiB

Open AccessArticle

Adaptive Environmental Source Localization and Tracking with Unknown Permittivity and Path Loss Coefficients

by Barış Fidan^*

and Ilknur Umay

Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave W, Waterloo, ON N2L 3G1, Canada

Sensors 2015, 15(12), 31125-31141; https://doi.org/10.3390/s151229852 - 10 Dec 2015

Cited by 15 | Viewed by 5563

Abstract

Accurate signal-source and signal-reflector target localization tasks via mobile sensory units and wireless sensor networks (WSNs), including those for environmental monitoring via sensory UAVs, require precise knowledge of specific signal propagation properties of the environment, which are permittivity and path loss coefficients for [...] Read more.

Accurate signal-source and signal-reflector target localization tasks via mobile sensory units and wireless sensor networks (WSNs), including those for environmental monitoring via sensory UAVs, require precise knowledge of specific signal propagation properties of the environment, which are permittivity and path loss coefficients for the electromagnetic signal case. Thus, accurate estimation of these coefficients has significant importance for the accuracy of location estimates. In this paper, we propose a geometric cooperative technique to instantaneously estimate such coefficients, with details provided for received signal strength (RSS) and time-of-flight (TOF)-based range sensors. The proposed technique is integrated to a recursive least squares (RLS)-based adaptive localization scheme and an adaptive motion control law, to construct adaptive target localization and adaptive target tracking algorithms, respectively, that are robust to uncertainties in aforementioned environmental signal propagation coefficients. The efficiency of the proposed adaptive localization and tracking techniques are both mathematically analysed and verified via simulation experiments. Full article

(This article belongs to the Special Issue UAV Sensors for Environmental Monitoring)

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29 pages, 549 KiB

Open AccessReview

Microfluidic Organ/Body-on-a-Chip Devices at the Convergence of Biology and Microengineering

by Ana Rubina Perestrelo^1,*

, Ana C. P. Águas²

, Alberto Rainer³ and Giancarlo Forte^1,4,*

¹ International Clinical Research Center (ICRC), Integrated Center of Cellular Therapy and Regenerative Medicine (ICCT), St. Anne’s University Hospital, Brno 656 91, Czech Republic

² Center for Biomedical Research, University of Algarve, Faro 8005-139, Portugal

³ Tissue Engineering Unit, Università Campus Bio-Medico di Roma, Rome 00128, Italy

⁴ Department of Biomaterials Science, University of Turku, Turku 20014, Finland

Sensors 2015, 15(12), 31142-31170; https://doi.org/10.3390/s151229848 - 10 Dec 2015

Cited by 131 | Viewed by 20140

Abstract

Recent advances in biomedical technologies are mostly related to the convergence of biology with microengineering. For instance, microfluidic devices are now commonly found in most research centers, clinics and hospitals, contributing to more accurate studies and therapies as powerful tools for drug delivery, [...] Read more.

Recent advances in biomedical technologies are mostly related to the convergence of biology with microengineering. For instance, microfluidic devices are now commonly found in most research centers, clinics and hospitals, contributing to more accurate studies and therapies as powerful tools for drug delivery, monitoring of specific analytes, and medical diagnostics. Most remarkably, integration of cellularized constructs within microengineered platforms has enabled the recapitulation of the physiological and pathological conditions of complex tissues and organs. The so-called “organ-on-a-chip” technology, which represents a new avenue in the field of advanced in vitro models, with the potential to revolutionize current approaches to drug screening and toxicology studies. This review aims to highlight recent advances of microfluidic-based devices towards a body-on-a-chip concept, exploring their technology and broad applications in the biomedical field. Full article

(This article belongs to the Special Issue Novel Biomaterials and Sensors for Tissue Engineering)

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9 pages, 3854 KiB

Open AccessArticle

Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications

by Seung-Hyun Eom, Yunsik Seo and Sungjoon Lim^*

Electrical and Electronics Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 06974, Korea

Sensors 2015, 15(12), 31171-31179; https://doi.org/10.3390/s151229851 - 10 Dec 2015

Cited by 20 | Viewed by 9201

Abstract

In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT) switch and [...] Read more.

In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT) switch and a balun element. A double-sided parallel-strip line (DSPSL) is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antennas have different radiation patterns because of the different orientation of the reflectors and antennas. It is demonstrated from electromagnetic (EM) simulation and measurement that the radiation patterns of the proposed antenna are successfully switched by the SPDT switch. Full article

(This article belongs to the Section Sensor Networks)

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25 pages, 12648 KiB

Open AccessArticle

Adjustment of Sonar and Laser Acquisition Data for Building the 3D Reference Model of a Canal Tunnel

by Emmanuel Moisan^1,2,*, Pierre Charbonnier¹, Philippe Foucher¹, Pierre Grussenmeyer²

, Samuel Guillemin² and Mathieu Koehl²

¹ Cerema Dter Est, Image Processing and Optical Methods Research Team, 11 rue Jean Mentelin, B.P. 9, Strasbourg 67035, France

² ICube Laboratory UMR 7357, Photogrammetry and Geomatics Group, INSA Strasbourg, 24 Boulevard de la Victoire, Strasbourg 67084, France

Sensors 2015, 15(12), 31180-31204; https://doi.org/10.3390/s151229855 - 11 Dec 2015

Cited by 26 | Viewed by 8901

Abstract

In this paper, we focus on the construction of a full 3D model of a canal tunnel by combining terrestrial laser (for its above-water part) and sonar (for its underwater part) scans collected from static acquisitions. The modeling of such a structure is [...] Read more.

In this paper, we focus on the construction of a full 3D model of a canal tunnel by combining terrestrial laser (for its above-water part) and sonar (for its underwater part) scans collected from static acquisitions. The modeling of such a structure is challenging because the sonar device is used in a narrow environment that induces many artifacts. Moreover, the location and the orientation of the sonar device are unknown. In our approach, sonar data are first simultaneously denoised and meshed. Then, above- and under-water point clouds are co-registered to generate directly the full 3D model of the canal tunnel. Faced with the lack of overlap between both models, we introduce a robust algorithm that relies on geometrical entities and partially-immersed targets, which are visible in both the laser and sonar point clouds. A full 3D model, visually promising, of the entrance of a canal tunnel is obtained. The analysis of the method raises several improvement directions that will help with obtaining more accurate models, in a more automated way, in the limits of the involved technology. Full article

(This article belongs to the Special Issue Sensors and Techniques for 3D Object Modeling in Underwater Environments)

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19 pages, 835 KiB

Open AccessArticle

Joint Temperature-Lasing Mode Compensation for Time-of-Flight LiDAR Sensors

by Anas Alhashimi^*

, Damiano Varagnolo

and Thomas Gustafsson

Control Engineering Group, Department of Computer Science, Electrical and Space Engineering, Luleå University of Technology, Luleå 97187, Sweden

Sensors 2015, 15(12), 31205-31223; https://doi.org/10.3390/s151229854 - 11 Dec 2015

Cited by 4 | Viewed by 5739

Abstract

We propose an expectation maximization (EM) strategy for improving the precision of time of flight (ToF) light detection and ranging (LiDAR) scanners. The novel algorithm statistically accounts not only for the bias induced by temperature changes in the laser diode, but also for [...] Read more.

We propose an expectation maximization (EM) strategy for improving the precision of time of flight (ToF) light detection and ranging (LiDAR) scanners. The novel algorithm statistically accounts not only for the bias induced by temperature changes in the laser diode, but also for the multi-modality of the measurement noises that is induced by mode-hopping effects. Instrumental to the proposed EM algorithm, we also describe a general thermal dynamics model that can be learned either from just input-output data or from a combination of simple temperature experiments and information from the laser’s datasheet. We test the strategy on a SICK LMS 200 device and improve its average absolute error by a factor of three. Full article

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

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20 pages, 557 KiB

Open AccessArticle

Energy-Efficient Algorithm for Multicasting in Duty-Cycled Sensor Networks

by Quan Chen¹

, Siyao Cheng¹

, Hong Gao^1,*, Jianzhong Li¹ and Zhipeng Cai²

¹ School of Computer Science and Technology, Harbin Institute of Technology, 92 West Dazhi Street, Harbin 150001, China

² Department of Computer Science, Georgia State University, Atlanta, GA 30303, USA

Sensors 2015, 15(12), 31224-31243; https://doi.org/10.3390/s151229860 - 11 Dec 2015

Cited by 22 | Viewed by 5362

Abstract

Multicasting is a fundamental network service for one-to-many communications in wireless sensor networks. However, when the sensor nodes work in an asynchronous duty-cycled way, the sender may need to transmit the same message several times to one group of its neighboring nodes, which [...] Read more.

Multicasting is a fundamental network service for one-to-many communications in wireless sensor networks. However, when the sensor nodes work in an asynchronous duty-cycled way, the sender may need to transmit the same message several times to one group of its neighboring nodes, which complicates the minimum energy multicasting problem. Thus, in this paper, we study the problem of minimum energy multicasting with adjusted power (the MEMAP problem) in the duty-cycled sensor networks, and we prove it to be NP-hard. To solve such a problem, the concept of an auxiliary graph is proposed to integrate the scheduling problem of the transmitting power and transmitting time slot and the constructing problem of the minimum multicast tree in MEMAP, and a greedy algorithm is proposed to construct such a graph. Based on the proposed auxiliary graph, an approximate scheduling and constructing algorithm with an approximation ratio of 4 l n K is proposed, where K is the number of destination nodes. Finally, the theoretical analysis and experimental results verify the efficiency of the proposed algorithm in terms of the energy cost and transmission redundancy. Full article

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

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24 pages, 8222 KiB

Open AccessArticle

An Indoor Continuous Positioning Algorithm on the Move by Fusing Sensors and Wi-Fi on Smartphones

by Huaiyu Li^1,*, Xiuwan Chen¹, Guifei Jing², Yuan Wang¹, Yanfeng Cao^1,3, Fei Li¹, Xinlong Zhang¹ and Han Xiao¹

¹ Institute of Remote Sensing and GIS, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871, China

² National Remote Sensing Center of China, No. 8A, Liulinguan Nanli, Haidian District, Beijing 100036, China

³ Beijing Aerospace Unmanned Vehicles System Engineering Research Institute, No. 1 Fengyingdong Road, Haidian District, Beijing 100094, China

Sensors 2015, 15(12), 31244-31267; https://doi.org/10.3390/s151229850 - 11 Dec 2015

Cited by 31 | Viewed by 6321

Abstract

Wi-Fi indoor positioning algorithms experience large positioning error and low stability when continuously positioning terminals that are on the move. This paper proposes a novel indoor continuous positioning algorithm that is on the move, fusing sensors and Wi-Fi on smartphones. The main innovative [...] Read more.

Wi-Fi indoor positioning algorithms experience large positioning error and low stability when continuously positioning terminals that are on the move. This paper proposes a novel indoor continuous positioning algorithm that is on the move, fusing sensors and Wi-Fi on smartphones. The main innovative points include an improved Wi-Fi positioning algorithm and a novel positioning fusion algorithm named the Trust Chain Positioning Fusion (TCPF) algorithm. The improved Wi-Fi positioning algorithm was designed based on the properties of Wi-Fi signals on the move, which are found in a novel “quasi-dynamic” Wi-Fi signal experiment. The TCPF algorithm is proposed to realize the “process-level” fusion of Wi-Fi and Pedestrians Dead Reckoning (PDR) positioning, including three parts: trusted point determination, trust state and positioning fusion algorithm. An experiment is carried out for verification in a typical indoor environment, and the average positioning error on the move is 1.36 m, a decrease of 28.8% compared to an existing algorithm. The results show that the proposed algorithm can effectively reduce the influence caused by the unstable Wi-Fi signals, and improve the accuracy and stability of indoor continuous positioning on the move. Full article

(This article belongs to the Section Sensor Networks)

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25 pages, 3893 KiB

Open AccessArticle

Control and Guidance of Low-Cost Robots via Gesture Perception for Monitoring Activities in the Home

by Angel D. Sempere^†, Arturo Serna-Leon^†, Pablo Gil^†

, Santiago Puente^*,†

and Fernando Torres^†

¹ Physics, Systems Engineering and Signal Theory Department, University of Alicante, San Vicente del Raspeig, E-03690 Alicante, Spain

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 31268-31292; https://doi.org/10.3390/s151229853 - 11 Dec 2015

Cited by 8 | Viewed by 6964

Abstract

This paper describes the development of a low-cost mini-robot that is controlled by visual gestures. The prototype allows a person with disabilities to perform visual inspections indoors and in domestic spaces. Such a device could be used as the operator's eyes obviating the [...] Read more.

This paper describes the development of a low-cost mini-robot that is controlled by visual gestures. The prototype allows a person with disabilities to perform visual inspections indoors and in domestic spaces. Such a device could be used as the operator's eyes obviating the need for him to move about. The robot is equipped with a motorised webcam that is also controlled by visual gestures. This camera is used to monitor tasks in the home using the mini-robot while the operator remains quiet and motionless. The prototype was evaluated through several experiments testing the ability to use the mini-robot’s kinematics and communication systems to make it follow certain paths. The mini-robot can be programmed with specific orders and can be tele-operated by means of 3D hand gestures to enable the operator to perform movements and monitor tasks from a distance. Full article

(This article belongs to the Section Physical Sensors)

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21 pages, 9444 KiB

Open AccessArticle

Design and Calibration of a New 6 DOF Haptic Device

by Huanhuan Qin¹, Aiguo Song^1,*, Yuqing Liu², Guohua Jiang² and Bohe Zhou²

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

² National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center, Beijing 100094, China

Sensors 2015, 15(12), 31293-31313; https://doi.org/10.3390/s151229857 - 11 Dec 2015

Cited by 29 | Viewed by 8743

Abstract

For many applications such as tele-operational robots and interactions with virtual environments, it is better to have performance with force feedback than without. Haptic devices are force reflecting interfaces. They can also track human hand positions simultaneously. A new 6 DOF (degree-of-freedom) haptic [...] Read more.

For many applications such as tele-operational robots and interactions with virtual environments, it is better to have performance with force feedback than without. Haptic devices are force reflecting interfaces. They can also track human hand positions simultaneously. A new 6 DOF (degree-of-freedom) haptic device was designed and calibrated in this study. It mainly contains a double parallel linkage, a rhombus linkage, a rotating mechanical structure and a grasping interface. Benefited from the unique design, it is a hybrid structure device with a large workspace and high output capability. Therefore, it is capable of multi-finger interactions. Moreover, with an adjustable base, operators can change different postures without interrupting haptic tasks. To investigate the performance regarding position tracking accuracy and static output forces, we conducted experiments on a three-dimensional electric sliding platform and a digital force gauge, respectively. Displacement errors and force errors are calculated and analyzed. To identify the capability and potential of the device, four application examples were programmed. Full article

(This article belongs to the Section Physical Sensors)

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25 pages, 2433 KiB

Open AccessReview

Physical Human Activity Recognition Using Wearable Sensors

by Ferhat Attal¹, Samer Mohammed^1,*, Mariam Dedabrishvili¹, Faicel Chamroukhi², Latifa Oukhellou³ and Yacine Amirat¹

¹ Laboratory of Images, Signals and Intelligent Systems (LISSI), University of Paris-Est Créteil (UPEC), 122 rue Paul Armangot, Vitry-Sur-Seine 94400, France

² Laboratory of Information Science and Systems (LSIS, CNRS-UMR7296), University of Toulon, Bâtiment R, BP 20132, La Garde Cedex 83957, France

³ French Institute of Science and Technology for Transport, development and Networks (IFSTTAR), University of Paris-Est, COSYS, GRETTIA, Marne la Vallée F-77447, France

Sensors 2015, 15(12), 31314-31338; https://doi.org/10.3390/s151229858 - 11 Dec 2015

Cited by 673 | Viewed by 36951

Abstract

This paper presents a review of different classification techniques used to recognize human activities from wearable inertial sensor data. Three inertial sensor units were used in this study and were worn by healthy subjects at key points of upper/lower body limbs (chest, right [...] Read more.

This paper presents a review of different classification techniques used to recognize human activities from wearable inertial sensor data. Three inertial sensor units were used in this study and were worn by healthy subjects at key points of upper/lower body limbs (chest, right thigh and left ankle). Three main steps describe the activity recognition process: sensors’ placement, data pre-processing and data classification. Four supervised classification techniques namely, k-Nearest Neighbor (k-NN), Support Vector Machines (SVM), Gaussian Mixture Models (GMM), and Random Forest (RF) as well as three unsupervised classification techniques namely, k-Means, Gaussian mixture models (GMM) and Hidden Markov Model (HMM), are compared in terms of correct classification rate, F-measure, recall, precision, and specificity. Raw data and extracted features are used separately as inputs of each classifier. The feature selection is performed using a wrapper approach based on the RF algorithm. Based on our experiments, the results obtained show that the k-NN classifier provides the best performance compared to other supervised classification algorithms, whereas the HMM classifier is the one that gives the best results among unsupervised classification algorithms. This comparison highlights which approach gives better performance in both supervised and unsupervised contexts. It should be noted that the obtained results are limited to the context of this study, which concerns the classification of the main daily living human activities using three wearable accelerometers placed at the chest, right shank and left ankle of the subject. Full article

(This article belongs to the Section Physical Sensors)

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23 pages, 8073 KiB

Open AccessArticle

Bimodal Biometric Verification Using the Fusion of Palmprint and Infrared Palm-Dorsum Vein Images

by Chih-Lung Lin^1,*

, Shih-Hung Wang², Hsu-Yung Cheng², Kuo-Chin Fan², Wei-Lieh Hsu³ and Chin-Rong Lai²

¹ Department of Electronic Engineering, Hwa Hsia University of Technology, 111 Gon Jhuan Rd., Chung Ho dist., New Taipei City 23568, Taiwan

² Institute of Computer Science and Information Engineering, National Central University, Taoyuan City 32001, Taiwan

³ Department of Computer Information and Network Engineering, Lunghwa University of Science and Technology, Taoyuan County 33306, Taiwan

Sensors 2015, 15(12), 31339-31361; https://doi.org/10.3390/s151229856 - 12 Dec 2015

Cited by 12 | Viewed by 8756

Abstract

In this paper, we present a reliable and robust biometric verification method based on bimodal physiological characteristics of palms, including the palmprint and palm-dorsum vein patterns. The proposed method consists of five steps: (1) automatically aligning and cropping the same region of interest [...] Read more.

In this paper, we present a reliable and robust biometric verification method based on bimodal physiological characteristics of palms, including the palmprint and palm-dorsum vein patterns. The proposed method consists of five steps: (1) automatically aligning and cropping the same region of interest from different palm or palm-dorsum images; (2) applying the digital wavelet transform and inverse wavelet transform to fuse palmprint and vein pattern images; (3) extracting the line-like features (LLFs) from the fused image; (4) obtaining multiresolution representations of the LLFs by using a multiresolution filter; and (5) using a support vector machine to verify the multiresolution representations of the LLFs. The proposed method possesses four advantages: first, both modal images are captured in peg-free scenarios to improve the user-friendliness of the verification device. Second, palmprint and vein pattern images are captured using a low-resolution digital scanner and infrared (IR) camera. The use of low-resolution images results in a smaller database. In addition, the vein pattern images are captured through the invisible IR spectrum, which improves antispoofing. Third, since the physiological characteristics of palmprint and vein pattern images are different, a hybrid fusing rule can be introduced to fuse the decomposition coefficients of different bands. The proposed method fuses decomposition coefficients at different decomposed levels, with different image sizes, captured from different sensor devices. Finally, the proposed method operates automatically and hence no parameters need to be set manually. Three thousand palmprint images and 3000 vein pattern images were collected from 100 volunteers to verify the validity of the proposed method. The results show a false rejection rate of 1.20% and a false acceptance rate of 1.56%. It demonstrates the validity and excellent performance of our proposed method comparing to other methods. Full article

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

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30 pages, 6411 KiB

Open AccessArticle

Towards an Autonomous Vision-Based Unmanned Aerial System against Wildlife Poachers

by Miguel A. Olivares-Mendez^1,*, Changhong Fu², Philippe Ludivig¹, Tegawendé F. Bissyandé¹, Somasundar Kannan¹, Maciej Zurad¹, Arun Annaiyan¹, Holger Voos¹ and Pascual Campoy²

¹ Interdisciplinary Centre for Security, Reliability and Trust, SnT - University of Luxembourg, 4 Rue Alphonse Weicker, L-2721 Luxembourg, Luxembourg

² Centre for Automation and Robotics (CAR), Universidad Politécnica de Madrid (UPM-CSIC), Calle de José Gutiérrez Abascal 2, 28006 Madrid, Spain

Sensors 2015, 15(12), 31362-31391; https://doi.org/10.3390/s151229861 - 12 Dec 2015

Cited by 96 | Viewed by 15295

Abstract

Poaching is an illegal activity that remains out of control in many countries. Based on the 2014 report of the United Nations and Interpol, the illegal trade of global wildlife and natural resources amounts to nearly $ 213 billion every year, which is [...] Read more.

Poaching is an illegal activity that remains out of control in many countries. Based on the 2014 report of the United Nations and Interpol, the illegal trade of global wildlife and natural resources amounts to nearly $ 213 billion every year, which is even helping to fund armed conflicts. Poaching activities around the world are further pushing many animal species on the brink of extinction. Unfortunately, the traditional methods to fight against poachers are not enough, hence the new demands for more efficient approaches. In this context, the use of new technologies on sensors and algorithms, as well as aerial platforms is crucial to face the high increase of poaching activities in the last few years. Our work is focused on the use of vision sensors on UAVs for the detection and tracking of animals and poachers, as well as the use of such sensors to control quadrotors during autonomous vehicle following and autonomous landing. Full article

(This article belongs to the Special Issue UAV Sensors for Environmental Monitoring)

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36 pages, 7548 KiB

Open AccessReview

A Survey of Wireless Sensor Network Based Air Pollution Monitoring Systems

by Wei Ying Yi^1,2

, Kin Ming Lo¹, Terrence Mak³, Kwong Sak Leung^1,2,*, Yee Leung^2,4 and Mei Ling Meng^5,6

¹ Department of Computer Science and Engineering, The Chinese University of Hong Kong, Shatin NT, Hong Kong, China

² Institute of Future Cities, The Chinese University of Hong Kong, Shatin NT, Hong Kong, China

³ Department of Electronics and Computer Science, University of Southampton, University Road, Southampton S017 1BJ, UK

⁴ Department of Geography and Resource Management, The Chinese University of Hong Kong, Shatin NT, Hong Kong, China

⁵ Department of Systems Engineering and Engineering Management, The Chinese University of Hong Kong, Shatin NT, Hong Kong, China

⁶ Stanley Ho Big Data Decision Analytics Research Center, The Chinese University of Hong Kong, Shatin NT, Hong Kong, China

Sensors 2015, 15(12), 31392-31427; https://doi.org/10.3390/s151229859 - 12 Dec 2015

Cited by 311 | Viewed by 28117

Abstract

The air quality in urban areas is a major concern in modern cities due to significant impacts of air pollution on public health, global environment, and worldwide economy. Recent studies reveal the importance of micro-level pollution information, including human personal exposure and acute [...] Read more.

The air quality in urban areas is a major concern in modern cities due to significant impacts of air pollution on public health, global environment, and worldwide economy. Recent studies reveal the importance of micro-level pollution information, including human personal exposure and acute exposure to air pollutants. A real-time system with high spatio-temporal resolution is essential because of the limited data availability and non-scalability of conventional air pollution monitoring systems. Currently, researchers focus on the concept of The Next Generation Air Pollution Monitoring System (TNGAPMS) and have achieved significant breakthroughs by utilizing the advance sensing technologies, MicroElectroMechanical Systems (MEMS) and Wireless Sensor Network (WSN). However, there exist potential problems of these newly proposed systems, namely the lack of 3D data acquisition ability and the flexibility of the sensor network. In this paper, we classify the existing works into three categories as Static Sensor Network (SSN), Community Sensor Network (CSN) and Vehicle Sensor Network (VSN) based on the carriers of the sensors. Comprehensive reviews and comparisons among these three types of sensor networks were also performed. Last but not least, we discuss the limitations of the existing works and conclude the objectives that we want to achieve in future systems. Full article

(This article belongs to the Section Sensor Networks)

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14 pages, 3277 KiB

Open AccessArticle

A Novel Error Model of Optical Systems and an On-Orbit Calibration Method for Star Sensors

by Shuang Wang, Yunhai Geng^* and Rongyu Jin

Research Center of Satellite Technology, Harbin Institute of Technology, Harbin 150001, China

Sensors 2015, 15(12), 31428-31441; https://doi.org/10.3390/s151229863 - 12 Dec 2015

Cited by 11 | Viewed by 6678

Abstract

In order to improve the on-orbit measurement accuracy of star sensors, the effects of image-plane rotary error, image-plane tilt error and distortions of optical systems resulting from the on-orbit thermal environment were studied in this paper. Since these issues will affect the precision [...] Read more.

In order to improve the on-orbit measurement accuracy of star sensors, the effects of image-plane rotary error, image-plane tilt error and distortions of optical systems resulting from the on-orbit thermal environment were studied in this paper. Since these issues will affect the precision of star image point positions, in this paper, a novel measurement error model based on the traditional error model is explored. Due to the orthonormal characteristics of image-plane rotary-tilt errors and the strong nonlinearity among these error parameters, it is difficult to calibrate all the parameters simultaneously. To solve this difficulty, for the new error model, a modified two-step calibration method based on the Extended Kalman Filter (EKF) and Least Square Methods (LSM) is presented. The former one is used to calibrate the main point drift, focal length error and distortions of optical systems while the latter estimates the image-plane rotary-tilt errors. With this calibration method, the precision of star image point position influenced by the above errors is greatly improved from 15.42% to 1.389%. Finally, the simulation results demonstrate that the presented measurement error model for star sensors has higher precision. Moreover, the proposed two-step method can effectively calibrate model error parameters, and the calibration precision of on-orbit star sensors is also improved obviously. Full article

(This article belongs to the Section Physical Sensors)

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11 pages, 1725 KiB

Open AccessArticle

Multiple-Parameter Estimation Method Based on Spatio-Temporal 2-D Processing for Bistatic MIMO Radar

by Shouguo Yang^1,*, Yong Li¹, Kunhui Zhang¹ and Weiping Tang²

¹ School of Electronics and Information, Northwestern Polytechnical University, Xi’an 710072, China

² Air and Missile Defense College, Air Force Engineering University, Xi’an 710051, China

Sensors 2015, 15(12), 31442-31452; https://doi.org/10.3390/s151229865 - 14 Dec 2015

Cited by 6 | Viewed by 4643

Abstract

A novel spatio-temporal 2-dimensional (2-D) processing method that can jointly estimate the transmitting-receiving azimuth and Doppler frequency for bistatic multiple-input multiple-output (MIMO) radar in the presence of spatial colored noise and an unknown number of targets is proposed. In the temporal domain, the [...] Read more.

A novel spatio-temporal 2-dimensional (2-D) processing method that can jointly estimate the transmitting-receiving azimuth and Doppler frequency for bistatic multiple-input multiple-output (MIMO) radar in the presence of spatial colored noise and an unknown number of targets is proposed. In the temporal domain, the cross-correlation of the matched filters’ outputs for different time-delay sampling is used to eliminate the spatial colored noise. In the spatial domain, the proposed method uses a diagonal loading method and subspace theory to estimate the direction of departure (DOD) and direction of arrival (DOA), and the Doppler frequency can then be accurately estimated through the estimation of the DOD and DOA. By skipping target number estimation and the eigenvalue decomposition (EVD) of the data covariance matrix estimation and only requiring a one-dimensional search, the proposed method achieves low computational complexity. Furthermore, the proposed method is suitable for bistatic MIMO radar with an arbitrary transmitted and received geometrical configuration. The correction and efficiency of the proposed method are verified by computer simulation results. Full article

(This article belongs to the Section Remote Sensors)

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11 pages, 3945 KiB

Open AccessArticle

The Impact of Housing on the Characteristics of Ceramic Pressure Sensors—An Issue of Design for Manufacturability

by Marina Santo Zarnik¹, Darko Belavic² and Franc Novak^3,*

¹ Hyb, d.o.o., Levicnikova 34, Sentjernej 8340, Slovenia

² HIPOT-RR d.o.o., Sentpeter 18, Otocec 8222, Slovenia

³ Jozef Stefan Institute, Jamova cesta 39, Ljubljana 1000, Slovenia

Sensors 2015, 15(12), 31453-31463; https://doi.org/10.3390/s151229866 - 14 Dec 2015

Cited by 4 | Viewed by 6022

Abstract

An exploratory study of the impact of housing on the characteristics of a low-temperature co-fired ceramic (LTCC) pressure sensor is presented. The ceramic sensor structure is sealed in a plastic housing. This may have non-negligible effect on the final characteristics and should be [...] Read more.

An exploratory study of the impact of housing on the characteristics of a low-temperature co-fired ceramic (LTCC) pressure sensor is presented. The ceramic sensor structure is sealed in a plastic housing. This may have non-negligible effect on the final characteristics and should be considered in the early design phase. The manufacturability issue mainly concerning the selection of available housing and the most appropriate materials was considered with respect to different requirements for low and high pressure ranges of operation. Numerical predictions showed the trends and helped reveal the critical design parameters. Proper selection of the adhesive material remains an essential issue. Curing of the epoxy adhesive may introduce non-negligible residual stresses, which considerably influence the sensor’s characteristics. Full article

(This article belongs to the Section Physical Sensors)

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18 pages, 3922 KiB

Open AccessArticle

Probabilistic Multi-Sensor Fusion Based Indoor Positioning System on a Mobile Device

by Xiang He, Daniel N. Aloi and Jia Li^*

Department of Electrical and Computer Engineering, Oakland University, 2200 N Squirrel Road, Rochester, MI 48309, USA

Sensors 2015, 15(12), 31464-31481; https://doi.org/10.3390/s151229867 - 14 Dec 2015

Cited by 31 | Viewed by 8145

Abstract

Nowadays, smart mobile devices include more and more sensors on board, such as motion sensors (accelerometer, gyroscope, magnetometer), wireless signal strength indicators (WiFi, Bluetooth, Zigbee), and visual sensors (LiDAR, camera). People have developed various indoor positioning techniques based on these sensors. In this [...] Read more.

Nowadays, smart mobile devices include more and more sensors on board, such as motion sensors (accelerometer, gyroscope, magnetometer), wireless signal strength indicators (WiFi, Bluetooth, Zigbee), and visual sensors (LiDAR, camera). People have developed various indoor positioning techniques based on these sensors. In this paper, the probabilistic fusion of multiple sensors is investigated in a hidden Markov model (HMM) framework for mobile-device user-positioning. We propose a graph structure to store the model constructed by multiple sensors during the offline training phase, and a multimodal particle filter to seamlessly fuse the information during the online tracking phase. Based on our algorithm, we develop an indoor positioning system on the iOS platform. The experiments carried out in a typical indoor environment have shown promising results for our proposed algorithm and system design. Full article

(This article belongs to the Special Issue Advanced Algorithms for Mobile Sensing: from Wireless Sensor Networks to Mobile Crowd Sensing)

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43 pages, 18795 KiB

Open AccessArticle

Robust 3D Position Estimation in Wide and Unconstrained Indoor Environments

by Annette Mossel

Institute of Software Technology and Interactive Systems, Vienna University of Technology, Favoritenstr, 9–11/188/2, Vienna 1040, Austria

Sensors 2015, 15(12), 31482-31524; https://doi.org/10.3390/s151229862 - 14 Dec 2015

Cited by 9 | Viewed by 10184

Abstract

In this paper, a system for 3D position estimation in wide, unconstrained indoor environments is presented that employs infrared optical outside-in tracking of rigid-body targets with a stereo camera rig. To overcome limitations of state-of-the-art optical tracking systems, a pipeline for robust target [...] Read more.

In this paper, a system for 3D position estimation in wide, unconstrained indoor environments is presented that employs infrared optical outside-in tracking of rigid-body targets with a stereo camera rig. To overcome limitations of state-of-the-art optical tracking systems, a pipeline for robust target identification and 3D point reconstruction has been investigated that enables camera calibration and tracking in environments with poor illumination, static and moving ambient light sources, occlusions and harsh conditions, such as fog. For evaluation, the system has been successfully applied in three different wide and unconstrained indoor environments, (1) user tracking for virtual and augmented reality applications, (2) handheld target tracking for tunneling and (3) machine guidance for mining. The results of each use case are discussed to embed the presented approach into a larger technological and application context. The experimental results demonstrate the system’s capabilities to track targets up to 100 m. Comparing the proposed approach to prior art in optical tracking in terms of range coverage and accuracy, it significantly extends the available tracking range, while only requiring two cameras and providing a relative 3D point accuracy with sub-centimeter deviation up to 30 m and low-centimeter deviation up to 100 m. Full article

(This article belongs to the Special Issue Sensors for Indoor Mapping and Navigation)

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33 pages, 2673 KiB

Open AccessArticle

Optical Sensors and Methods for Underwater 3D Reconstruction

by Miquel Massot-Campos^* and Gabriel Oliver-Codina

Department of Mathematics and Computer Science, University of the Balearic Islands, Cra de Valldemossa km 7.5, Palma de Mallorca 07122, Spain

Sensors 2015, 15(12), 31525-31557; https://doi.org/10.3390/s151229864 - 15 Dec 2015

Cited by 161 | Viewed by 19256

Abstract

This paper presents a survey on optical sensors and methods for 3D reconstruction in underwater environments. The techniques to obtain range data have been listed and explained, together with the different sensor hardware that makes them possible. The literature has been reviewed, and [...] Read more.

This paper presents a survey on optical sensors and methods for 3D reconstruction in underwater environments. The techniques to obtain range data have been listed and explained, together with the different sensor hardware that makes them possible. The literature has been reviewed, and a classification has been proposed for the existing solutions. New developments, commercial solutions and previous reviews in this topic have also been gathered and considered. Full article

(This article belongs to the Special Issue Sensors and Techniques for 3D Object Modeling in Underwater Environments)

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8 pages, 586 KiB

Open AccessArticle

Ultrasensitive Detection of Testosterone Using Microring Resonator with Molecularly Imprinted Polymers

by Yangqing Chen¹, Yong Liu¹, Xiaodan Shen¹, Zhimin Chang², Longhua Tang¹, Wen-Fei Dong², Mingyu Li^1,* and Jian-Jun He¹

¹ State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027, Zhejiang, China

² CAS Key Lab of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, Jiangsu, China

Sensors 2015, 15(12), 31558-31565; https://doi.org/10.3390/s151229877 - 15 Dec 2015

Cited by 19 | Viewed by 8617

Abstract

We report ultrasensitive and highly selective detection of testosterone based on microring resonance sensor using molecularly imprinted polymers (MIP). A silicon-on-insulator (SOI) micoring resonator was modified by MIP films (MIPs) on a surface. The MIPs was synthesized by thermopolymerization using methacrylic acid as [...] Read more.

We report ultrasensitive and highly selective detection of testosterone based on microring resonance sensor using molecularly imprinted polymers (MIP). A silicon-on-insulator (SOI) micoring resonator was modified by MIP films (MIPs) on a surface. The MIPs was synthesized by thermopolymerization using methacrylic acid as functional monomer and ethylene glycol dimethacrylate as crosslinking agent. The concentration of detected testosterone varies from 0.05 ng/mL to 10 ng/mL. The detection limit reaches 48.7 pg/mL. Ultrahigh sensitivity, good specificity and reproducibility have been demonstrated, indicating the great potential of making a cost effective and easy to operate lab-on-Chip and down scaling micro-fluidics devices in biosensing. Full article

(This article belongs to the Section Biosensors)

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15 pages, 1889 KiB

Open AccessArticle

Multidirectional Image Sensing for Microscopy Based on a Rotatable Robot

by Yajing Shen^1,2,*, Wenfeng Wan¹, Lijun Zhang^1,4, Li Yong³, Haojian Lu¹ and Weili Ding^3,*

¹ Mechanical and Biomedical Engineering Department, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China

² CityU Shenzhen Research Institute, Shen Zhen, 8 Yuexing 1st Road, Shenzhen 518000, China

³ Institute of Electrical Engineering, Yanshan University, 438 Hebei Street West Section, Haigang, Qinhuangdao 066004, China

⁴ College of Electromechanical Engineering, University of Petroleum (East China), No. 66, Changjiang West Road, Huangdao District, Qingdao 266580, China

Sensors 2015, 15(12), 31566-31580; https://doi.org/10.3390/s151229872 - 15 Dec 2015

Cited by 17 | Viewed by 6415

Abstract

Image sensing at a small scale is essentially important in many fields, including microsample observation, defect inspection, material characterization and so on. However, nowadays, multi-directional micro object imaging is still very challenging due to the limited field of view (FOV) of microscopes. This [...] Read more.

Image sensing at a small scale is essentially important in many fields, including microsample observation, defect inspection, material characterization and so on. However, nowadays, multi-directional micro object imaging is still very challenging due to the limited field of view (FOV) of microscopes. This paper reports a novel approach for multi-directional image sensing in microscopes by developing a rotatable robot. First, a robot with endless rotation ability is designed and integrated with the microscope. Then, the micro object is aligned to the rotation axis of the robot automatically based on the proposed forward-backward alignment strategy. After that, multi-directional images of the sample can be obtained by rotating the robot within one revolution under the microscope. To demonstrate the versatility of this approach, we view various types of micro samples from multiple directions in both optical microscopy and scanning electron microscopy, and panoramic images of the samples are processed as well. The proposed method paves a new way for the microscopy image sensing, and we believe it could have significant impact in many fields, especially for sample detection, manipulation and characterization at a small scale. Full article

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

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25 pages, 3542 KiB

Open AccessReview

Through-Metal-Wall Power Delivery and Data Transmission for Enclosed Sensors: A Review

by Ding-Xin Yang^*,†, Zheng Hu^†, Hong Zhao, Hai-Feng Hu, Yun-Zhe Sun and Bao-Jian Hou

¹ Science and Technology on Integrated Logistics Support Laboratory, National University of Defense Technology, Changsha 410073, China

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 31581-31605; https://doi.org/10.3390/s151229870 - 15 Dec 2015

Cited by 101 | Viewed by 12632

Abstract

The aim of this review was to assess the current viable technologies for wireless power delivery and data transmission through metal barriers. Using such technologies sensors enclosed in hermetical metal containers can be powered and communicate through exterior power sources without penetration of [...] Read more.

The aim of this review was to assess the current viable technologies for wireless power delivery and data transmission through metal barriers. Using such technologies sensors enclosed in hermetical metal containers can be powered and communicate through exterior power sources without penetration of the metal wall for wire feed-throughs. In this review, we first discuss the significant and essential requirements for through-metal-wall power delivery and data transmission and then we: (1) describe three electromagnetic coupling based techniques reported in the literature, which include inductive coupling, capacitive coupling, and magnetic resonance coupling; (2) present a detailed review of wireless ultrasonic through-metal-wall power delivery and/or data transmission methods; (3) compare various ultrasonic through-metal-wall systems in modeling, transducer configuration and communication mode with sensors; (4) summarize the characteristics of electromagnetic-based and ultrasound-based systems, evaluate the challenges and development trends. We conclude that electromagnetic coupling methods are suitable for through thin non-ferromagnetic metal wall power delivery and data transmission at a relatively low data rate; piezoelectric transducer-based ultrasonic systems are particularly advantageous in achieving high power transfer efficiency and high data rates; the combination of more than one single technique may provide a more practical and reliable solution for long term operation. Full article

(This article belongs to the Section State-of-the-Art Sensors Technologies)

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14 pages, 7136 KiB

Open AccessArticle

Theoretical and Experimental Study of Radial Velocity Generation for Extending Bandwidth of Magnetohydrodynamic Angular Rate Sensor at Low Frequency

by Yue Ji¹, Xingfei Li^1,*, Tengfei Wu¹ and Cheng Chen²

¹ State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China

² School of Mechanical Engineering, Tianjin University of Commerce, Tianjin 300134, China

Sensors 2015, 15(12), 31606-31619; https://doi.org/10.3390/s151229869 - 15 Dec 2015

Cited by 20 | Viewed by 7459

Abstract

The magnetohydrodynamics angular rate sensor (MHD ARS) has received much attention for its ultra-low noise in ultra-broad bandwidth and its impact resistance in harsh environments; however, its poor performance at low frequency hinders its work in long time duration. The paper presents a [...] Read more.

The magnetohydrodynamics angular rate sensor (MHD ARS) has received much attention for its ultra-low noise in ultra-broad bandwidth and its impact resistance in harsh environments; however, its poor performance at low frequency hinders its work in long time duration. The paper presents a modified MHD ARS combining Coriolis with MHD effect to extend the measurement scope throughout the whole bandwidth, in which an appropriate radial flow velocity should be provided to satisfy simplified model of the modified MHD ARS. A method that can generate radial velocity by an MHD pump in MHD ARS is proposed. A device is designed to study the radial flow velocity generated by the MHD pump. The influence of structure and physical parameters are studied by numerical simulation and experiment of the device. The analytic expression of the velocity generated by the energized current drawn from simulation and experiment are consistent, which demonstrates the effectiveness of the method generating radial velocity. The study can be applied to generate and control radial velocity in modified MHD ARS, which is essential for the two effects combination throughout the whole bandwidth. Full article

(This article belongs to the Special Issue Sensors for Harsh Environments)

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24 pages, 728 KiB

Open AccessArticle

Event Coverage Detection and Event Source Determination in Underwater Wireless Sensor Networks

by Zhangbing Zhou^1,2,3, Riliang Xing², Yucong Duan^4,*, Yueqin Zhu⁵ and Jianming Xiang²

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

² School of Information Engineering, China University of Geosciences (Beijing), Beijing 100083, China

³ Computer Science Department, TELECOM SudParis, Evry 91 011, France

⁴ College of Information Science and Technology, Hainan University, Haikou 570228, China

⁵ Development Research Center of China Geological Survey, and Key Laboratory of Geological Information Technology, Ministry of Land and Resources, Beijing 100037, China

Sensors 2015, 15(12), 31620-31643; https://doi.org/10.3390/s151229875 - 15 Dec 2015

Cited by 17 | Viewed by 5529

Abstract

With the advent of the Internet of Underwater Things, smart things are deployed in the ocean space and establish underwater wireless sensor networks for the monitoring of vast and dynamic underwater environments. When events are found to have possibly occurred, accurate event coverage [...] Read more.

With the advent of the Internet of Underwater Things, smart things are deployed in the ocean space and establish underwater wireless sensor networks for the monitoring of vast and dynamic underwater environments. When events are found to have possibly occurred, accurate event coverage should be detected, and potential event sources should be determined for the enactment of prompt and proper responses. To address this challenge, a technique that detects event coverage and determines event sources is developed in this article. Specifically, the occurrence of possible events corresponds to a set of neighboring sensor nodes whose sensory data may deviate from a normal sensing range in a collective fashion. An appropriate sensor node is selected as the relay node for gathering and routing sensory data to sink node(s). When sensory data are collected at sink node(s), the event coverage is detected and represented as a weighted graph, where the vertices in this graph correspond to sensor nodes and the weight specified upon the edges reflects the extent of sensory data deviating from a normal sensing range. Event sources are determined, which correspond to the barycenters in this graph. The results of the experiments show that our technique is more energy efficient, especially when the network topology is relatively steady. Full article

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

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28 pages, 4026 KiB

Open AccessArticle

Robust Hand Motion Tracking through Data Fusion of 5DT Data Glove and Nimble VR Kinect Camera Measurements

by Ewout A. Arkenbout^*, Joost C. F. De Winter and Paul Breedveld

Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands

Sensors 2015, 15(12), 31644-31671; https://doi.org/10.3390/s151229868 - 15 Dec 2015

Cited by 36 | Viewed by 11127

Abstract

Vision based interfaces for human computer interaction have gained increasing attention over the past decade. This study presents a data fusion approach of the Nimble VR vision based system, using the Kinect camera, with the contact based 5DT Data Glove. Data fusion was [...] Read more.

Vision based interfaces for human computer interaction have gained increasing attention over the past decade. This study presents a data fusion approach of the Nimble VR vision based system, using the Kinect camera, with the contact based 5DT Data Glove. Data fusion was achieved through a Kalman filter. The Nimble VR and filter output were compared using measurements performed on (1) a wooden hand model placed in various static postures and orientations; and (2) three differently sized human hands during active finger flexions. Precision and accuracy of joint angle estimates as a function of hand posture and orientation were determined. Moreover, in light of possible self-occlusions of the fingers in the Kinect camera images, data completeness was assessed. Results showed that the integration of the Data Glove through the Kalman filter provided for the proximal interphalangeal (PIP) joints of the fingers a substantial improvement of 79% in precision, from 2.2 deg to 0.9 deg. Moreover, a moderate improvement of 31% in accuracy (being the mean angular deviation from the true joint angle) was established, from 24 deg to 17 deg. The metacarpophalangeal (MCP) joint was relatively unaffected by the Kalman filter. Moreover, the Data Glove increased data completeness, thus providing a substantial advantage over the sole use of the Nimble VR system. Full article

(This article belongs to the Section Physical Sensors)

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15 pages, 4439 KiB

Open AccessArticle

Opportunistic Hybrid Transport Protocol (OHTP) for Cognitive Radio Ad Hoc Sensor Networks

by Yousaf Bin Zikria¹

, Summera Nosheen²

, Farruh Ishmanov³ and Sung Won Kim^1,*

¹ Department of Information and Communication Engineering, Yeungnam University, 280, Daehak-Ro, Gyeongsan, Geongbuk 38541, Korea

² Comsats Institute of Information Technology, Park Rd, Islamabad 45550, Pakistan

³ Department of Electronics and Communication Engineering, Kwangwoon University, 447-1 Wolgye-dong, Nowon-gu, Seoul 01897, Korea

Sensors 2015, 15(12), 31672-31686; https://doi.org/10.3390/s151229871 - 15 Dec 2015

Cited by 13 | Viewed by 5728

Abstract

The inefficient assignment of spectrum for different communications purposes, plus technology enhancements and ever-increasing usage of wireless technology is causing spectrum scarcity. To address this issue, one of the proposed solutions in the literature is to access the spectrum dynamically or opportunistically. Therefore, [...] Read more.

The inefficient assignment of spectrum for different communications purposes, plus technology enhancements and ever-increasing usage of wireless technology is causing spectrum scarcity. To address this issue, one of the proposed solutions in the literature is to access the spectrum dynamically or opportunistically. Therefore, the concept of cognitive radio appeared, which opens up a new research paradigm. There is extensive research on the physical, medium access control and network layers. The impact of the transport layer on the performance of cognitive radio ad hoc sensor networks is still unknown/unexplored. The Internet’s de facto transport protocol is not well suited to wireless networks because of its congestion control mechanism. We propose an opportunistic hybrid transport protocol for cognitive radio ad hoc sensor networks. We developed a new congestion control mechanism to differentiate true congestion from interruption loss. After such detection and differentiation, we propose methods to handle them opportunistically. There are several benefits to window- and rate-based protocols. To exploit the benefits of both in order to enhance overall system performance, we propose a hybrid transport protocol. We empirically calculate the optimal threshold value to switch between window- and rate-based mechanisms. We then compare our proposed transport protocol to Transmission Control Protocol (TCP)-friendly rate control, TCP-friendly rate control for cognitive radio, and TCP-friendly window-based control. We ran an extensive set of simulations in Network Simulator 2. The results indicate that the proposed transport protocol performs better than all the others. Full article

(This article belongs to the Section Sensor Networks)

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12 pages, 4916 KiB

Open AccessArticle

CO Sensing Performance of a Micro Thermoelectric Gas Sensor with AuPtPd/SnO₂ Catalyst and Effects of a Double Catalyst Structure with Pt/α-Al₂O₃

by Tomoyo Goto^*,†

, Toshio Itoh, Takafumi Akamatsu and Woosuck Shin^*

¹ National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Shimo-Shidami, Moriyama-ku, Nagoya 463-8560, Japan

^† Present address: The Institute of Scientific and Industrial Research (ISIR), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan

Sensors 2015, 15(12), 31687-31698; https://doi.org/10.3390/s151229873 - 15 Dec 2015

Cited by 17 | Viewed by 7161

Abstract

The CO sensing properties of a micro thermoelectric gas sensor (micro-TGS) with a double AuPtPd/SnO₂ and Pt/α-Al₂O₃ catalyst were investigated. While several nanometer sized Pt and Pd particles were uniformly dispersed on SnO₂, the Au particles were [...] Read more.

The CO sensing properties of a micro thermoelectric gas sensor (micro-TGS) with a double AuPtPd/SnO₂ and Pt/α-Al₂O₃ catalyst were investigated. While several nanometer sized Pt and Pd particles were uniformly dispersed on SnO₂, the Au particles were aggregated as particles measuring >10 nm in diameter. In situ diffuse reflectance Fourier transform Infrared spectroscopy (DRIFT) analysis of the catalyst showed a CO adsorption peak on Pt and Pd, but no clear peak corresponding to the interaction between CO and Au was detected. Up to 200 °C, CO combustion was more temperature dependent than that of H₂, while H₂ combustion was activated by repeated exposure to H₂ gas during the periodic gas test. Selective CO sensing of the micro-TGS against H₂ was attempted using a double catalyst structure with 0.3–30 wt% Pt/α-Al₂O₃ as a counterpart combustion catalyst. The sensor output of the micro-TGS decreased with increasing Pt content in the Pt/α-Al₂O₃ catalyst, by cancelling out the combustion heat from the AuPtPd/SnO₂ catalyst. In addition, the AuPtPd/SnO₂ and 0.3 wt% Pt/α-Al₂O₃ double catalyst sensor showed good and selective CO detection. We therefore demonstrated that our micro-TGS with double catalyst structure is useful for controlling the gas selectivity of CO against H₂. Full article

(This article belongs to the Section Chemical Sensors)

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10 pages, 4772 KiB

Open AccessArticle

Periodical Microstructures Based on Novel Piezoelectric Material for Biomedical Applications

by Giedrius Janusas¹

, Sigita Ponelyte^1,*, Alfredas Brunius¹, Asta Guobiene², Igoris Prosycevas¹, Andrius Vilkauskas¹ and Arvydas Palevicius¹

¹ Faculty of Mechanical Engineering and Design, Kaunas University of Technology; Studentu str. 56, Kaunas LT-51424, Lithuania

² Institute of Materials Science, Kaunas University of Technology, Barsausko str. 59, Kaunas LT-51423, Lithuania

Sensors 2015, 15(12), 31699-31708; https://doi.org/10.3390/s151229876 - 15 Dec 2015

Cited by 12 | Viewed by 5779

Abstract

A novel cantilever type piezoelectric sensing element was developed. Cost-effective and simple fabrication design allows the use of this element for various applications in the areas of biomedicine, pharmacy, environmental analysis and biosensing. This paper proposes a novel piezoelectric composite material whose basic [...] Read more.

A novel cantilever type piezoelectric sensing element was developed. Cost-effective and simple fabrication design allows the use of this element for various applications in the areas of biomedicine, pharmacy, environmental analysis and biosensing. This paper proposes a novel piezoelectric composite material whose basic element is PZT and a sensing platform where this material was integrated. Results showed that a designed novel cantilever-type element is able to generate a voltage of up to 80 µV at 50 Hz frequency. To use this element for sensing purposes, a four micron periodical microstructure was imprinted. Silver nanoparticles were precipitated on the grating to increase the sensitivity of the designed element, i.e., Surface Plasmon Resonance (SPR) effect appears in the element. To tackle some issues (a lack of sensitivity, signal delays) the element must have certain electronic and optical properties. One possible solution, proposed in this paper, is a combination of piezoelectricity and SPR in a single element. Full article

(This article belongs to the Section Physical Sensors)

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14 pages, 979 KiB

Open AccessArticle

A Vibrotactile and Plantar Force Measurement-Based Biofeedback System: Paving the Way towards Wearable Balance-Improving Devices

by Christina Zong-Hao Ma^1,2

, Anson Hong-Ping Wan¹

, Duo Wai-Chi Wong¹

, Yong-Ping Zheng¹

and Winson Chiu-Chun Lee^1,3,*

¹ Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong, China

² Rehabilitation Engineering Research Institute, China Rehabilitation Research Center, Beijing 100068, China

³ Institute of Active Ageing, The Hong Kong Polytechnic University, Hong Kong, China

Sensors 2015, 15(12), 31709-31722; https://doi.org/10.3390/s151229883 - 15 Dec 2015

Cited by 35 | Viewed by 8869

Abstract

Although biofeedback systems have been used to improve balance with success, they were confined to hospital training applications. Little attempt has been made to investigate the use of in-shoe plantar force measurement and wireless technology to turn hospital training biofeedback systems into wearable [...] Read more.

Although biofeedback systems have been used to improve balance with success, they were confined to hospital training applications. Little attempt has been made to investigate the use of in-shoe plantar force measurement and wireless technology to turn hospital training biofeedback systems into wearable devices. This research developed a wearable biofeedback system which detects body sway by analyzing the plantar force and provides users with the corresponding haptic cues. The effects of this system were evaluated in thirty young and elderly subjects with simulated reduced foot sensation. Subjects performed a Romberg test under three conditions: (1) no socks, system turned-off; (2) wearing five layers of socks, system turned-off; (3) wearing five layers of socks, and system turned-on. Degree of body sway was investigated by computing the center of pressure (COP) movement measured by a floor-mounted force platform. Plantar tactile sensation was evaluated using a monofilament test. Wearing multiple socks significantly decreased the plantar tactile sensory input (p < 0.05), and increased the COP parameters (p < 0.017), indicating increased postural sway. After turning on the biofeedback system, the COP parameters decreased significantly (p < 0.017). The positive results of this study should inspire future development of wearable plantar force-based biofeedback systems for improving balance in people with sensory deficits. Full article

(This article belongs to the Special Issue Wearable Sensors)

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15 pages, 2421 KiB

Open AccessArticle

Subjective Quality Assessment of Underwater Video for Scientific Applications

by José-Miguel Moreno-Roldán^1,*

, Miguel-Ángel Luque-Nieto¹

, Javier Poncela¹

, Víctor Díaz-del-Río² and Pablo Otero¹

¹ Department of Communication Engineering, University of Málaga, 29071 Málaga, Spain

² Spanish Institute of Oceanography, 29649 Fuengirola, Spain

Sensors 2015, 15(12), 31723-31737; https://doi.org/10.3390/s151229882 - 15 Dec 2015

Cited by 13 | Viewed by 5800

Abstract

Underwater video services could be a key application in the better scientific knowledge of the vast oceanic resources in our planet. However, limitations in the capacity of current available technology for underwater networks (UWSNs) raise the question of the feasibility of these services. [...] Read more.

Underwater video services could be a key application in the better scientific knowledge of the vast oceanic resources in our planet. However, limitations in the capacity of current available technology for underwater networks (UWSNs) raise the question of the feasibility of these services. When transmitting video, the main constraints are the limited bandwidth and the high propagation delays. At the same time the service performance depends on the needs of the target group. This paper considers the problems of estimations for the Mean Opinion Score (a standard quality measure) in UWSNs based on objective methods and addresses the topic of quality assessment in potential underwater video services from a subjective point of view. The experimental design and the results of a test planned according standardized psychometric methods are presented. The subjects used in the quality assessment test were ocean scientists. Video sequences were recorded in actual exploration expeditions and were processed to simulate conditions similar to those that might be found in UWSNs. Our experimental results show how videos are considered to be useful for scientific purposes even in very low bitrate conditions. Full article

(This article belongs to the Special Issue Underwater Sensor Nodes and Underwater Sensor Networks 2016)

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13 pages, 9132 KiB

Open AccessArticle

Smart Sensing Strip Using Monolithically Integrated Flexible Flow Sensor for Noninvasively Monitoring Respiratory Flow

by Peng Jiang, Shuai Zhao and Rong Zhu^*

State Key Laboratory of Precision Measurement Technology and Instrument, Department of Precision Instrument, Tsinghua University, Beijing 100084, China

Sensors 2015, 15(12), 31738-31750; https://doi.org/10.3390/s151229881 - 15 Dec 2015

Cited by 61 | Viewed by 13156

Abstract

This paper presents a smart sensing strip for noninvasively monitoring respiratory flow in real time. The monitoring system comprises a monolithically-integrated flexible hot-film flow sensor adhered on a molded flexible silicone case, where a miniaturized conditioning circuit with a Bluetooth4.0 LE module are [...] Read more.

This paper presents a smart sensing strip for noninvasively monitoring respiratory flow in real time. The monitoring system comprises a monolithically-integrated flexible hot-film flow sensor adhered on a molded flexible silicone case, where a miniaturized conditioning circuit with a Bluetooth4.0 LE module are packaged, and a personal mobile device that wirelessly acquires respiratory data transmitted from the flow sensor, executes extraction of vital signs, and performs medical diagnosis. The system serves as a wearable device to monitor comprehensive respiratory flow while avoiding use of uncomfortable nasal cannula. The respiratory sensor is a flexible flow sensor monolithically integrating four elements of a Wheatstone bridge on single chip, including a hot-film resistor, a temperature-compensating resistor, and two balancing resistors. The monitor takes merits of small size, light weight, easy operation, and low power consumption. Experiments were conducted to verify the feasibility and effectiveness of monitoring and diagnosing respiratory diseases using the proposed system. Full article

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

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11 pages, 32983 KiB

Open AccessArticle

An RFID Based Smart Feeder for Hummingbirds

by Vicente Ibarra¹, Marcelo Araya-Salas², Yu-ping Tang³, Charlie Park³, Anthony Hyde³, Timothy F. Wright^2,*

and Wei Tang^1,*

¹ Klipsch School of Electrical and Computer Engineering, New Mexico State University, Las Cruces, NM 88003, USA

² Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA

³ Manufacturing Technology and Engineering Center, New Mexico State University, Las Cruces, NM 88003, USA

Sensors 2015, 15(12), 31751-31761; https://doi.org/10.3390/s151229886 - 16 Dec 2015

Cited by 14 | Viewed by 10167

Abstract

We present an interdisciplinary effort to record feeding behaviors and control the diet of a hummingbird species (Phaethornis longirostris, the long-billed hermit or LBH) by developing a Radio Frequency Identification (RFID) based smart feeder. The system contains an RFID reader, a [...] Read more.

We present an interdisciplinary effort to record feeding behaviors and control the diet of a hummingbird species (Phaethornis longirostris, the long-billed hermit or LBH) by developing a Radio Frequency Identification (RFID) based smart feeder. The system contains an RFID reader, a microcontroller, and a servo-controlled hummingbird feeder opener; the system is presented as a tool for studying the cognitive ability of the LBH species. When equipped with glass capsule RFID tags (which are mounted on the hummingbird), the smart feeder can provide specific diets for predetermined sets of hummingbirds at the discretion of biologists. This is done by reading the unique RFID tag on the hummingbirds and comparing the ID number with the pre-programmed ID numbers stored in the smart feeder. The smart feeder records the time and ID of each hummingbird visit. The system data is stored in a readily available SD card and is powered by two 9 V batteries. The detection range of the system is approximately 9–11 cm. Using this system, biologists can assign the wild hummingbirds to different experimental groups and monitor their diets to determine if they develop a preference to any of the available nectars. During field testing, the smart feeder system has demonstrated consistent detection (when compared to detections observed by video-recordings) of RFID tags on hummingbirds and provides pre-designed nectars varying water and sugar concentrations to target individuals. The smart feeder can be applied to other biological and environmental studies in the future. Full article

(This article belongs to the Section Physical Sensors)

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19 pages, 5151 KiB

Open AccessArticle

Smart Capture Modules for Direct Sensor-to-FPGA Interfaces

by Óscar Oballe-Peinado^1,2

, Fernando Vidal-Verdú^1,2,*, José A. Sánchez-Durán^1,2

, Julián Castellanos-Ramos^1,2

and José A. Hidalgo-López^1,2

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

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

Sensors 2015, 15(12), 31762-31780; https://doi.org/10.3390/s151229878 - 16 Dec 2015

Cited by 19 | Viewed by 6808

Abstract

Direct sensor–digital device interfaces measure time dependent variables of simple circuits to implement analog-to-digital conversion. Field Programmable Gate Arrays (FPGAs) are devices whose hardware can be reconfigured to work in parallel. They usually do not have analog-to-digital converters, but have many general purpose [...] Read more.

Direct sensor–digital device interfaces measure time dependent variables of simple circuits to implement analog-to-digital conversion. Field Programmable Gate Arrays (FPGAs) are devices whose hardware can be reconfigured to work in parallel. They usually do not have analog-to-digital converters, but have many general purpose I/O pins. Therefore, direct sensor-FPGA connection is a good choice in complex systems with many sensors because several capture modules can be implemented to perform parallel analog data acquisition. The possibility to work in parallel and with high frequency clock signals improves the bandwidth compared to sequential devices such as conventional microcontrollers. The price to pay is usually the resolution of measurements. This paper proposes capture modules implemented in an FPGA which are able to perform smart acquisition that filter noise and achieve high precision. A calibration technique is also proposed to improve accuracy. Resolutions of 12 effective number of bits are obtained for the reading of resistors in the range of an example piezoresistive tactile sensor. Full article

(This article belongs to the Section Physical Sensors)

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13 pages, 4221 KiB

Open AccessArticle

GSA-Tuning IPD Control of a Field-Sensed Magnetic Suspension System

by Jen-Hsing Li¹ and Juing-Shian Chiou^2,*

¹ Department of Electrical Engineering, Kun Shan University, 195 Kunda Road, Yongkang District, Tainan City 710, Taiwan

² Department of Electrical Engineering, Southern Taiwan University of Science and Technology, 1 Nan Ti Street, Yongkang District, Tainan City 710, Taiwan

Sensors 2015, 15(12), 31781-31793; https://doi.org/10.3390/s151229879 - 16 Dec 2015

Cited by 6 | Viewed by 8139

Abstract

The purpose of this paper is to propose a GSA-tuning IPD control technique for magnetic suspension systems. An educational demonstration on a magnetic-field sensed magnetic suspension system is examined for effectiveness. For the magnetic-field sensed magnetic suspension system (FSMSS), the current transducer is [...] Read more.

The purpose of this paper is to propose a GSA-tuning IPD control technique for magnetic suspension systems. An educational demonstration on a magnetic-field sensed magnetic suspension system is examined for effectiveness. For the magnetic-field sensed magnetic suspension system (FSMSS), the current transducer is employed for measuring the electromagnetic coil current, and a Hall effect device is used for detecting the position of the suspended object. To achieve optimal performance, the gravitational search algorithm (GSA) is adopted for tuning the integral-proportional-derivative (IPD) controller. The IPD control includes the specified PD controller and an integrator. The specified PD control is employed for stabilizing the inherently unstable FSMSS, whereas the integral control is utilized for eliminating the steady-state error. The GSA can tune the IPD control parameters to enable optimal FSMSS performance. We achieved excellent results from the simulations and hands-on experiments for the proposed control strategies and structures. Full article

(This article belongs to the Special Issue Magnetic Sensor Device-Part 1)

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17 pages, 1429 KiB

Open AccessArticle

Sensing Traffic Density Combining V2V and V2I Wireless Communications

by Julio A. Sanguesa¹

, Javier Barrachina¹, Manuel Fogue¹, Piedad Garrido¹, Francisco J. Martinez^1,*

, Juan-Carlos Cano²

, Carlos T. Calafate²

and Pietro Manzoni²

¹ DIIS, University of Zaragoza, Ciudad Escolar s/n, Teruel 44003, Spain

² DISCA, Universitat Politècnica de València, Camino de Vera s/n, Valencia 46022, Spain

Sensors 2015, 15(12), 31794-31810; https://doi.org/10.3390/s151229889 - 16 Dec 2015

Cited by 53 | Viewed by 13377

Abstract

Wireless technologies are making the development of new applications and services in vehicular environments possible since they enable mobile communication between vehicles (V2V), as well as communication between vehicles and infrastructure nodes (V2I). Usually, V2V communications are dedicated to the transmission of small [...] Read more.

Wireless technologies are making the development of new applications and services in vehicular environments possible since they enable mobile communication between vehicles (V2V), as well as communication between vehicles and infrastructure nodes (V2I). Usually, V2V communications are dedicated to the transmission of small messages mainly focused on improving traffic safety. Instead, V2I communications allow users to access the Internet and benefit from higher level applications. The combination of both V2V and V2I, known as V2X communications, can increase the benefits even further, thereby making intelligent transportation systems (ITS) a reality. In this paper, we introduce V2X-d, a novel architecture specially designed to estimate traffic density on the road. In particular, V2X-d exploits the combination of V2V and V2I communications. Our approach is based on the information gathered by sensors (i.e., vehicles and road side units (RSUs)) and the characteristics of the roadmap topology to accurately make an estimation of the instant vehicle density. The combination of both mechanisms improves the accuracy and coverage area of the data gathered, while increasing the robustness and fault tolerance of the overall approach, e.g., using the information offered by V2V communications to provide additional density information in areas where RSUs are scarce or malfunctioning. By using our collaborative sensing scheme, future ITS solutions will be able to establish adequate dissemination protocols or to apply more efficient traffic congestion reduction policies, since they will be aware of the instantaneous density of vehicles. Full article

(This article belongs to the Section Sensor Networks)

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10 pages, 2596 KiB

Open AccessArticle

Mechanism of Electrochemical Delamination of Two-Dimensional Materials from Their Native Substrates by Bubbling

by Jie Sun^1,2,*

, Xing Fan¹, Weiling Guo^1,*, Lihui Liu², Xin Liu¹, Jun Deng¹ and Chen Xu¹

¹ Key Laboratory of Optoelectronics Technology, College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124, China

² Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg 41296, Sweden

Sensors 2015, 15(12), 31811-31820; https://doi.org/10.3390/s151229888 - 16 Dec 2015

Cited by 6 | Viewed by 8505

Abstract

A capacitor-based circuit model is proposed to explain the electrochemical delamination of two-dimensional materials from their native substrates where produced gas bubbles squeeze into the interface. The delamination is actually the electric breakdown of the capacitor formed between the solution and substrate. To [...] Read more.

A capacitor-based circuit model is proposed to explain the electrochemical delamination of two-dimensional materials from their native substrates where produced gas bubbles squeeze into the interface. The delamination is actually the electric breakdown of the capacitor formed between the solution and substrate. To facilitate the procedure, the backside of the ubstrate has to be shielded so that the capacitor breakdown voltage can be reached. The screening effect can be induced either by nonreactive ions around the electrode or, more effectively, by an undetachable insulator. This mechanism serves as a guideline for the surface science and applications involving the bubbling delamination. Full article

(This article belongs to the Special Issue Graphene and 2D Material Bionanosensors: Chemistry Matters)

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12 pages, 6510 KiB

Open AccessArticle

Co-Design Method and Wafer-Level Packaging Technique of Thin-Film Flexible Antenna and Silicon CMOS Rectifier Chips for Wireless-Powered Neural Interface Systems

by Kenji Okabe¹, Horagodage Prabhath Jeewan¹, Shota Yamagiwa¹, Takeshi Kawano¹, Makoto Ishida^1,2 and Ippei Akita^1,*

¹ Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Aichi 441-8580, Japan

² Electronics-Inspired Interdisciplinary Research Institute (EIIRIS), Toyohashi University of Technology, Aichi 441-8580, Japan

Sensors 2015, 15(12), 31821-31832; https://doi.org/10.3390/s151229885 - 16 Dec 2015

Cited by 10 | Viewed by 18324

Abstract

In this paper, a co-design method and a wafer-level packaging technique of a flexible antenna and a CMOS rectifier chip for use in a small-sized implantable system on the brain surface are proposed. The proposed co-design method optimizes the system architecture, and can [...] Read more.

In this paper, a co-design method and a wafer-level packaging technique of a flexible antenna and a CMOS rectifier chip for use in a small-sized implantable system on the brain surface are proposed. The proposed co-design method optimizes the system architecture, and can help avoid the use of external matching components, resulting in the realization of a small-size system. In addition, the technique employed to assemble a silicon large-scale integration (LSI) chip on the very thin parylene film (5 μm) enables the integration of the rectifier circuits and the flexible antenna (rectenna). In the demonstration of wireless power transmission (WPT), the fabricated flexible rectenna achieved a maximum efficiency of 0.497% with a distance of 3 cm between antennas. In addition, WPT with radio waves allows a misalignment of 185% against antenna size, implying that the misalignment has a less effect on the WPT characteristics compared with electromagnetic induction. Full article

(This article belongs to the Section Physical Sensors)

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10 pages, 1738 KiB

Open AccessArticle

PCF Based Sensor with High Sensitivity, High Birefringence and Low Confinement Losses for Liquid Analyte Sensing Applications

by Huseyin Ademgil^1,† and Shyqyri Haxha^2,*,†

¹ Department of Computer Engineering, European University of Lefke, Mersin 10, Turkey

² Department of Computer Science and Technologies, University of Bedfordshire, University Square, Luton, Bedfordshire LU1 3JU, UK

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 31833-31842; https://doi.org/10.3390/s151229891 - 16 Dec 2015

Cited by 176 | Viewed by 9905

Abstract

In this paper, we report a design of high sensitivity Photonic Crystal Fiber (PCF) sensor with high birefringence and low confinement losses for liquid analyte sensing applications. The proposed PCF structures are designed with supplementary elliptical air holes in the core region vertically-shaped [...] Read more.

In this paper, we report a design of high sensitivity Photonic Crystal Fiber (PCF) sensor with high birefringence and low confinement losses for liquid analyte sensing applications. The proposed PCF structures are designed with supplementary elliptical air holes in the core region vertically-shaped V-PCF and horizontally-shaped H-PCF. The full vectorial Finite Element Method (FEM) simulations performed to examine the sensitivity, the confinement losses, the effective refractive index and the modal birefringence features of the proposed elliptical air hole PCF structures. We show that the proposed PCF structures exhibit high relative sensitivity, high birefringence and low confinement losses simultaneously for various analytes. Full article

(This article belongs to the Section Physical Sensors)

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16 pages, 2901 KiB

Open AccessArticle

A Security Assessment Mechanism for Software-Defined Networking-Based Mobile Networks

by Shibo Luo¹

, Mianxiong Dong^2,*, Kaoru Ota²

, Jun Wu¹ and Jianhua Li¹

¹ School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200041, China

² Department of Information and Electric Engineering, Muroran Institute of Technology, Muroran 050-8585, Japan

Sensors 2015, 15(12), 31843-31858; https://doi.org/10.3390/s151229887 - 17 Dec 2015

Cited by 19 | Viewed by 9017

Abstract

Software-Defined Networking-based Mobile Networks (SDN-MNs) are considered the future of 5G mobile network architecture. With the evolving cyber-attack threat, security assessments need to be performed in the network management. Due to the distinctive features of SDN-MNs, such as their dynamic nature and complexity, [...] Read more.

Software-Defined Networking-based Mobile Networks (SDN-MNs) are considered the future of 5G mobile network architecture. With the evolving cyber-attack threat, security assessments need to be performed in the network management. Due to the distinctive features of SDN-MNs, such as their dynamic nature and complexity, traditional network security assessment methodologies cannot be applied directly to SDN-MNs, and a novel security assessment methodology is needed. In this paper, an effective security assessment mechanism based on attack graphs and an Analytic Hierarchy Process (AHP) is proposed for SDN-MNs. Firstly, this paper discusses the security assessment problem of SDN-MNs and proposes a methodology using attack graphs and AHP. Secondly, to address the diversity and complexity of SDN-MNs, a novel attack graph definition and attack graph generation algorithm are proposed. In order to quantify security levels, the Node Minimal Effort (NME) is defined to quantify attack cost and derive system security levels based on NME. Thirdly, to calculate the NME of an attack graph that takes the dynamic factors of SDN-MN into consideration, we use AHP integrated with the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) as the methodology. Finally, we offer a case study to validate the proposed methodology. The case study and evaluation show the advantages of the proposed security assessment mechanism. Full article

(This article belongs to the Section Sensor Networks)

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10 pages, 320 KiB

Open AccessArticle

Localization of Mixed Completely and Partially Polarized Signals with Crossed-Dipole Sensor Arrays

by Kun Wang¹, Jin He^2,*, Ting Shu² and Zhong Liu¹

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

² Shanghai Key Laboratory of Intelligent Sensing and Recognition, Department of Electronic Engineering, Shanghai Jiaotong University, Shanghai 200240, China

Sensors 2015, 15(12), 31859-31868; https://doi.org/10.3390/s151229894 - 17 Dec 2015

Cited by 13 | Viewed by 5292

Abstract

In this paper, we investigate the problem of source localization and classification under the coexistence of both completely polarized (CP) and partially polarized (PP) electromagnetic (EM) signals, using a crossed-dipole sensor array. We propose a MUltiple SIgnal Classification (MUSIC)-based solution, which does not [...] Read more.

In this paper, we investigate the problem of source localization and classification under the coexistence of both completely polarized (CP) and partially polarized (PP) electromagnetic (EM) signals, using a crossed-dipole sensor array. We propose a MUltiple SIgnal Classification (MUSIC)-based solution, which does not require multidimensional searches. Moreover, the proposed method need no estimation of the degree of polarization of signals. The efficacy of the proposed method is examined by comparing with existing methods. Full article

(This article belongs to the Section Physical Sensors)

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19 pages, 5216 KiB

Open AccessArticle

Quantitative Evaluation of Stereo Visual Odometry for Autonomous Vessel Localisation in Inland Waterway Sensing Applications

by Thomas Kriechbaumer¹, Kim Blackburn², Toby P. Breckon³

, Oliver Hamilton³ and Monica Rivas Casado^1,*

¹ School of Energy, Environmental Technology and Agrifood, Cranfield University, Cranfield MK43 0AL, UK

² School of Aerospace, Transport Systems and Manufacturing, Cranfield University, Cranfield MK43 0AL, UK

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

Sensors 2015, 15(12), 31869-31887; https://doi.org/10.3390/s151229892 - 17 Dec 2015

Cited by 18 | Viewed by 9567

Abstract

Autonomous survey vessels can increase the efficiency and availability of wide-area river environment surveying as a tool for environment protection and conservation. A key challenge is the accurate localisation of the vessel, where bank-side vegetation or urban settlement preclude the conventional use of [...] Read more.

Autonomous survey vessels can increase the efficiency and availability of wide-area river environment surveying as a tool for environment protection and conservation. A key challenge is the accurate localisation of the vessel, where bank-side vegetation or urban settlement preclude the conventional use of line-of-sight global navigation satellite systems (GNSS). In this paper, we evaluate unaided visual odometry, via an on-board stereo camera rig attached to the survey vessel, as a novel, low-cost localisation strategy. Feature-based and appearance-based visual odometry algorithms are implemented on a six degrees of freedom platform operating under guided motion, but stochastic variation in yaw, pitch and roll. Evaluation is based on a 663 m-long trajectory (>15,000 image frames) and statistical error analysis against ground truth position from a target tracking tachymeter integrating electronic distance and angular measurements. The position error of the feature-based technique (mean of ±0.067 m) is three times smaller than that of the appearance-based algorithm. From multi-variable statistical regression, we are able to attribute this error to the depth of tracked features from the camera in the scene and variations in platform yaw. Our findings inform effective strategies to enhance stereo visual localisation for the specific application of river monitoring. Full article

(This article belongs to the Special Issue Robotic Sensory Systems for Environment Protection and Conservation)

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16 pages, 2304 KiB

Open AccessArticle

Study on the Sensing Coating of the Optical Fibre CO₂ Sensor

by Karol Wysokiński^1,*, Marek Napierała^1,2, Tomasz Stańczyk^3,†, Stanisław Lipiński^1,†

and Tomasz Nasiłowski¹

¹ InPhoTech, 17 Słomińskiego St31, 00-195 Warszawa, Poland

² IPT Safety, Ceramiczna St 8A, 20-150 Lublin, Poland

³ Polish Centre for Photonics and Fibre Optics, Rogoźnica 312, 36-060 Głogów Małopolski, Poland

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 31888-31903; https://doi.org/10.3390/s151229890 - 17 Dec 2015

Cited by 31 | Viewed by 8971

Abstract

Optical fibre carbon dioxide (CO₂) sensors are reported in this article. The principle of operation of the sensors relies on the absorption of light transmitted through the fibre by a silica gel coating containing active dyes, including methyl red, thymol blue [...] Read more.

Optical fibre carbon dioxide (CO₂) sensors are reported in this article. The principle of operation of the sensors relies on the absorption of light transmitted through the fibre by a silica gel coating containing active dyes, including methyl red, thymol blue and phenol red. Stability of the sensor has been investigated for the first time for an absorption based CO₂ optical fiber sensor. Influence of the silica gel coating thickness on the sensitivity and response time has also been studied. The impact of temperature and humidity on the sensor performance has been examined too. Response times of reported sensors are very short and reach 2–3 s, whereas the sensitivity of the sensor ranges from 3 to 10 for different coating thicknesses. Reported parameters make the sensor suitable for indoor and industrial use. Full article

(This article belongs to the Special Issue Gas Sensors—Designs and Applications)

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10 pages, 780 KiB

Open AccessArticle

A Dual Sensor for pH and Hydrogen Peroxide Using Polymer-Coated Optical Fibre Tips

by Malcolm S. Purdey^1,2,3,*, Jeremy G. Thompson^1,2,4, Tanya M. Monro^1,2,5, Andrew D. Abell^1,2,3 and Erik P. Schartner^1,2

¹ ARC Centre of Excellence for Nanoscale BioPhotonics, Adelaide 5005, SA, Australia

² Institute for Photonics and Advanced Sensing (IPAS), The University of Adelaide, North Terrace, Adelaide 5005, SA, Australia

³ Discipline of Chemistry, School of Physical Sciences, The University of Adelaide, North Terrace, Adelaide 5005, SA, Australia

⁴ Robinson Research Institute, School of Medicine, The University of Adelaide, North Terrace, Adelaide 5005, SA, Australia

⁵ University of South Australia, North Terrace, Adelaide 5001, SA, Australia

Sensors 2015, 15(12), 31904-31913; https://doi.org/10.3390/s151229893 - 17 Dec 2015

Cited by 40 | Viewed by 10534

Abstract

This paper demonstrates the first single optical fibre tip probe for concurrent detection of both hydrogen peroxide (H₂O₂) concentration and pH of a solution. The sensor is constructed by embedding two fluorophores: carboxyperoxyfluor-1 (CPF1) and seminaphtharhodafluor-2 (SNARF2) within a [...] Read more.

This paper demonstrates the first single optical fibre tip probe for concurrent detection of both hydrogen peroxide (H₂O₂) concentration and pH of a solution. The sensor is constructed by embedding two fluorophores: carboxyperoxyfluor-1 (CPF1) and seminaphtharhodafluor-2 (SNARF2) within a polymer matrix located on the tip of the optical fibre. The functionalised fibre probe reproducibly measures pH, and is able to accurately detect H₂O₂ over a biologically relevant concentration range. This sensor offers potential for non-invasive detection of pH and H₂O₂ in biological environments using a single optical fibre. Full article

(This article belongs to the Section Chemical Sensors)

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16 pages, 1158 KiB

Open AccessArticle

An Analog Circuit Approximation of the Discrete Wavelet Transform for Ultra Low Power Signal Processing in Wearable Sensor Nodes

by Alexander J. Casson

School of Electrical and Electronic Engineering, The University of Manchester, Manchester M13 9PL, UK

Sensors 2015, 15(12), 31914-31929; https://doi.org/10.3390/s151229897 - 17 Dec 2015

Cited by 11 | Viewed by 8510

Abstract

Ultra low power signal processing is an essential part of all sensor nodes, and particularly so in emerging wearable sensors for biomedical applications. Analog signal processing has an important role in these low power, low voltage, low frequency applications, and there is a [...] Read more.

Ultra low power signal processing is an essential part of all sensor nodes, and particularly so in emerging wearable sensors for biomedical applications. Analog signal processing has an important role in these low power, low voltage, low frequency applications, and there is a key drive to decrease the power consumption of existing analog domain signal processing and to map more signal processing approaches into the analog domain. This paper presents an analog domain signal processing circuit which approximates the output of the Discrete Wavelet Transform (DWT) for use in ultra low power wearable sensors. Analog filters are used for the DWT filters and it is demonstrated how these generate analog domain DWT-like information that embeds information from Butterworth and Daubechies maximally flat mother wavelet responses. The Analog DWT is realised in hardware via g m C circuits, designed to operate from a 1.3 V coin cell battery, and provide DWT-like signal processing using under 115 nW of power when implemented in a 0.18 μm CMOS process. Practical examples demonstrate the effective use of the new Analog DWT on ECG (electrocardiogram) and EEG (electroencephalogram) signals recorded from humans. Full article

(This article belongs to the Section State-of-the-Art Sensors Technologies)

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9 pages, 3984 KiB

Open AccessArticle

Formation of High-Purity Indium Oxide Nanoparticles and Their Application to Sensitive Detection of Ammonia

by Sanjeev K. Bhardwaj^1,2, Neha Bhardwaj^1,2, Manil Kukkar^1,2, Amit L. Sharma^1,2

, Ki-Hyun Kim^3,*

and Akash Deep^1,2,*

¹ Central Scientific Instruments Organisation (CSIR-CSIO), Sector 30 C, Chandigarh 160030, India

² Academy of Scientific and Innovative Research, CSIR-CSIO, Sector 30 C, Chandigarh 160030, India

³ Department of Civil & Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul 04763, Korea

Sensors 2015, 15(12), 31930-31938; https://doi.org/10.3390/s151229895 - 17 Dec 2015

Cited by 14 | Viewed by 6545

Abstract

High-purity In₂O₃ nanoparticles were recovered from scrap indium tin oxide substrates in a stepwise process involving acidic leaching, liquid-liquid extraction with a phosphine oxide extractant, and combustion of the organic phase. The morphological and structural parameters of the recovered nanoparticles [...] Read more.

High-purity In₂O₃ nanoparticles were recovered from scrap indium tin oxide substrates in a stepwise process involving acidic leaching, liquid-liquid extraction with a phosphine oxide extractant, and combustion of the organic phase. The morphological and structural parameters of the recovered nanoparticles were investigated to support the formation of the desired products. These In₂O₃ nanoparticles were used for sensitive sensing of ammonia gas using a four-probe electrode device. The proposed sensor offered very quick response time (around 10 s) and highly sensitive detection of ammonia (at a detection limit of 1 ppm). Full article

(This article belongs to the Special Issue The Use of New and/or Improved Materials for Sensing Applications)

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26 pages, 5814 KiB

Open AccessArticle

Flexibility Support for Homecare Applications Based on Models and Multi-Agent Technology

by Aintzane Armentia^1,*

, Unai Gangoiti^1,†, Rafael Priego^1,†, Elisabet Estévez^2,† and Marga Marcos^1,†

¹ Automatic Control & Systems Engineering Department, ETSI Bilbao, University of the Basque Country (UPV/EHU), 48013 Bilbao, Spain

² Electronic and Automation Engineering Department, University of Jaen (UJA), 23071 Jaén, Spain

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 31939-31964; https://doi.org/10.3390/s151229899 - 17 Dec 2015

Cited by 15 | Viewed by 6995

Abstract

In developed countries, public health systems are under pressure due to the increasing percentage of population over 65. In this context, homecare based on ambient intelligence technology seems to be a suitable solution to allow elderly people to continue to enjoy the comforts [...] Read more.

In developed countries, public health systems are under pressure due to the increasing percentage of population over 65. In this context, homecare based on ambient intelligence technology seems to be a suitable solution to allow elderly people to continue to enjoy the comforts of home and help optimize medical resources. Thus, current technological developments make it possible to build complex homecare applications that demand, among others, flexibility mechanisms for being able to evolve as context does (adaptability), as well as avoiding service disruptions in the case of node failure (availability). The solution proposed in this paper copes with these flexibility requirements through the whole life-cycle of the target applications: from design phase to runtime. The proposed domain modeling approach allows medical staff to design customized applications, taking into account the adaptability needs. It also guides software developers during system implementation. The application execution is managed by a multi-agent based middleware, making it possible to meet adaptation requirements, assuring at the same time the availability of the system even for stateful applications. Full article

(This article belongs to the Section Physical Sensors)

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8 pages, 1827 KiB

Open AccessCommunication

Development and Preliminary Evaluation of a Spray Deposition Sensing System for Improving Pesticide Application

by Melissa A. Kesterson^1,†, Joe D. Luck^2,* and Michael P. Sama³

¹ Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583, USA

² Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583, USA

³ Department of Biosystems and Agricultural Engineering, University of Kentucky, Lexington, KY 40546, USA

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 31965-31972; https://doi.org/10.3390/s151229898 - 17 Dec 2015

Cited by 18 | Viewed by 5359

Abstract

An electronic, resistance-based sensor array and data acquisition system was developed to measure spray deposition from hydraulic nozzles. The sensor surface consisted of several parallel tin plated copper traces of varying widths with varying gap widths. The system contained an embedded microprocessor to [...] Read more.

An electronic, resistance-based sensor array and data acquisition system was developed to measure spray deposition from hydraulic nozzles. The sensor surface consisted of several parallel tin plated copper traces of varying widths with varying gap widths. The system contained an embedded microprocessor to monitor output voltage corresponding to spray deposition every second. In addition, a wireless module was used to transmit the voltage values to a remote laptop. Tests were conducted in two stages to evaluate the performance of the sensor array in an attempt to quantify the spray deposition. Initial tests utilized manual droplet placement on the sensor surface to determine the effects of temperature and droplet size on voltage output. Secondary testing utilized a spray chamber to pass nozzles at different speeds above the sensor surface to determine if output varied based on different application rates or spray droplet classification. Results from this preliminary analysis indicated that manual droplets of 5 and 10 μL resulted in significantly different values from the sensors while temperature did not consistently affect output. Spray chamber test results indicated that different application rates and droplet sizes could be determined using the sensor array. Full article

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14 pages, 2857 KiB

Open AccessArticle

Pharmacokinetics of Chiral Dendrimer-Triamine-Coordinated Gd-MRI Contrast Agents Evaluated by in Vivo MRI and Estimated by in Vitro QCM

by Yuka Miyake¹, Syungo Ishikawa¹, Yu Kimura^1,2, Aoi Son¹, Hirohiko Imai³, Tetsuya Matsuda³, Hisatsugu Yamada^1,4,†, Akio Toshimitsu^1,5 and Teruyuki Kondo^1,4,*

¹ Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan

² Research and Educational Unit of Leaders for Integrated Medical System, Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan

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

⁴ Advanced Biomedical Engineering Research Unit, Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan

⁵ Division of Multidisciplinary Chemistry, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan

^† Present Address: Department of Life System, Institute of Technology and Science, Graduate School, Tokushima University, Tokushima 770-8506, Japan

Sensors 2015, 15(12), 31973-31986; https://doi.org/10.3390/s151229900 - 18 Dec 2015

Cited by 7 | Viewed by 6600

Abstract

Recently, we developed novel chiral dendrimer-triamine-coordinated Gd-MRI contrast agents (Gd-MRI CAs), which showed longitudinal relaxivity (r₁) values about four times higher than that of clinically used Gd-DTPA (Magnevist^®, Bayer). In our continuing study of pharmacokinetic differences derived from [...] Read more.

Recently, we developed novel chiral dendrimer-triamine-coordinated Gd-MRI contrast agents (Gd-MRI CAs), which showed longitudinal relaxivity (r₁) values about four times higher than that of clinically used Gd-DTPA (Magnevist^®, Bayer). In our continuing study of pharmacokinetic differences derived from both the chirality and generation of Gd-MRI CAs, we found that the ability of chiral dendrimer Gd-MRI CAs to circulate within the body can be directly evaluated by in vitro MRI (7 T). In this study, the association constants (K_a) of chiral dendrimer Gd-MRI CAs to bovine serum albumin (BSA), measured and calculated with a quartz crystal microbalance (QCM) in vitro, were found to be an extremely easy means for evaluating the body-circulation ability of chiral dendrimer Gd-MRI CAs. The K_a values of S-isomeric dendrimer Gd-MRI CAs were generally greater than those of R-isomeric dendrimer Gd-MRI CAs, which is consistent with the results of our previous MRI study in vivo. Full article

(This article belongs to the Section Biosensors)

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12 pages, 2332 KiB

Open AccessArticle

Synthesis and Sensing Applications of Fluorescent 3-Cinnamoyl Coumarins

by Preeti Yadav¹, Hardeep Singh Gill², Karam Chand^1,3, Lian Li², Jayant Kumar^2,* and Sunil K. Sharma^1,*

¹ Department of Chemistry, University of Delhi, Delhi 110007, India

² Center for Advanced Materials, University of Massachusetts Lowell, Lowell, MA 01854, USA

³ Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal

Sensors 2015, 15(12), 31987-31998; https://doi.org/10.3390/s151229902 - 19 Dec 2015

Cited by 7 | Viewed by 8016

Abstract

We have synthesized two novel fluorescent 3-(4-diethylaminocinnamoyl) coumarins that exhibit fluorescence quenching upon exposure to a nerve agent simulant, diethylchlorophosphate (DCP), providing a basis for rapid and sensitive DCP chemosensing. Furthermore, these coumarin derivatives display two-photon fluorescence upon illumination with near-infrared laser pulses [...] Read more.

We have synthesized two novel fluorescent 3-(4-diethylaminocinnamoyl) coumarins that exhibit fluorescence quenching upon exposure to a nerve agent simulant, diethylchlorophosphate (DCP), providing a basis for rapid and sensitive DCP chemosensing. Furthermore, these coumarin derivatives display two-photon fluorescence upon illumination with near-infrared laser pulses and their two-photon (TP) absorption cross-section was evaluated. The potential for TP bio-imaging of these compounds was investigated by their cellular uptake in HeLa cells by TP confocal microscopy. Full article

(This article belongs to the Special Issue The Use of New and/or Improved Materials for Sensing Applications)

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21 pages, 992 KiB

Open AccessArticle

One Small Step for a Man: Estimation of Gender, Age and Height from Recordings of One Step by a Single Inertial Sensor

by Qaiser Riaz^1,*

, Anna Vögele¹, Björn Krüger²

and Andreas Weber¹

¹ Department of Computer Science II, Universität Bonn, Bonn 53113, Germany

² Gokhale Method Institute, Stanford, CA 94305, USA

Sensors 2015, 15(12), 31999-32019; https://doi.org/10.3390/s151229907 - 19 Dec 2015

Cited by 63 | Viewed by 9186

Abstract

A number of previous works have shown that information about a subject is encoded in sparse kinematic information, such as the one revealed by so-called point light walkers. With the work at hand, we extend these results to classifications of soft biometrics from [...] Read more.

A number of previous works have shown that information about a subject is encoded in sparse kinematic information, such as the one revealed by so-called point light walkers. With the work at hand, we extend these results to classifications of soft biometrics from inertial sensor recordings at a single body location from a single step. We recorded accelerations and angular velocities of 26 subjects using integrated measurement units (IMUs) attached at four locations (chest, lower back, right wrist and left ankle) when performing standardized gait tasks. The collected data were segmented into individual walking steps. We trained random forest classifiers in order to estimate soft biometrics (gender, age and height). We applied two different validation methods to the process, 10-fold cross-validation and subject-wise cross-validation. For all three classification tasks, we achieve high accuracy values for all four sensor locations. From these results, we can conclude that the data of a single walking step (6D: accelerations and angular velocities) allow for a robust estimation of the gender, height and age of a person. Full article

(This article belongs to the Collection Sensors for Globalized Healthy Living and Wellbeing)

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11 pages, 3548 KiB

Open AccessArticle

Technological Advancement in Tower-Based Canopy Reflectance Monitoring: The AMSPEC-III System

by Riccardo Tortini^1,*, Thomas Hilker², Nicholas C. Coops¹

and Zoran Nesic³

¹ Integrated Remote Sensing Studio, Department of Forest Resources Management, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada

² College of Forestry, Oregon State University, 231 Peavy Hall, Corvallis, OR 97333, USA

³ Faculty of Land and Food Systems, Univeristy of British Columbia, 2357 Main Mall, Vancouver, BC V6T 1Z4, Canada

Sensors 2015, 15(12), 32020-32030; https://doi.org/10.3390/s151229906 - 19 Dec 2015

Cited by 10 | Viewed by 7546

Abstract

Understanding plant photosynthesis, or Gross Primary Production (GPP), is a crucial aspect of quantifying the terrestrial carbon cycle. Remote sensing approaches, in particular multi-angular spectroscopy, have proven successful for studying relationships between canopy-reflectance and plant-physiology processes, thus providing a mechanism to scale up. [...] Read more.

Understanding plant photosynthesis, or Gross Primary Production (GPP), is a crucial aspect of quantifying the terrestrial carbon cycle. Remote sensing approaches, in particular multi-angular spectroscopy, have proven successful for studying relationships between canopy-reflectance and plant-physiology processes, thus providing a mechanism to scale up. However, many different instrumentation designs exist and few cross-comparisons have been undertaken. This paper discusses the design evolution of the Automated Multiangular SPectro-radiometer for Estimation of Canopy reflectance (AMSPEC) series of instruments. Specifically, we assess the performance of the PP-Systems Unispec-DC and Ocean Optics JAZ-COMBO spectro-radiometers installed on an updated, tower-based AMSPEC-III system. We demonstrate the interoperability of these spectro-radiometers, and the results obtained suggest that JAZ-COMBO can successfully be used to substitute more expensive measurement units for detecting and investigating photosynthesis and canopy spectra. We demonstrate close correlations between JAZ-COMBO and Unispec-DC measured canopy radiance (0.75 ≤ R² ≤ 0.85) and solar irradiance (0.95 ≤ R² ≤ 0.96) over a three month time span. We also demonstrate close agreement between the bi-directional distribution functions obtained from each instrument. We conclude that cost effective alternatives may allow a network of AMSPEC-III systems to simultaneously monitor various vegetation types in different ecosystems. This will allow to scale and improve our understanding of the interactions between vegetation physiology and spectral characteristics, calibrate broad-scale observations to stand-level measurements, and ultimately lead to improved understanding of changing vegetation spectral features from satellite. Full article

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

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14 pages, 2510 KiB

Open AccessArticle

A Simulation Environment for Benchmarking Sensor Fusion-Based Pose Estimators

by Gabriele Ligorio^* and Angelo Maria Sabatini

The BioRobotics Institute, Scuola Superiore Sant’Anna, Piazza Martiri della Libertà 33, Pisa 56125, Italy

Sensors 2015, 15(12), 32031-32044; https://doi.org/10.3390/s151229903 - 19 Dec 2015

Cited by 6 | Viewed by 7700

Abstract

In-depth analysis and performance evaluation of sensor fusion-based estimators may be critical when performed using real-world sensor data. For this reason, simulation is widely recognized as one of the most powerful tools for algorithm benchmarking. In this paper, we present a simulation framework [...] Read more.

In-depth analysis and performance evaluation of sensor fusion-based estimators may be critical when performed using real-world sensor data. For this reason, simulation is widely recognized as one of the most powerful tools for algorithm benchmarking. In this paper, we present a simulation framework suitable for assessing the performance of sensor fusion-based pose estimators. The systems used for implementing the framework were magnetic/inertial measurement units (MIMUs) and a camera, although the addition of further sensing modalities is straightforward. Typical nuisance factors were also included for each sensor. The proposed simulation environment was validated using real-life sensor data employed for motion tracking. The higher mismatch between real and simulated sensors was about 5% of the measured quantity (for the camera simulation), whereas a lower correlation was found for an axis of the gyroscope (0.90). In addition, a real benchmarking example of an extended Kalman filter for pose estimation from MIMU and camera data is presented. Full article

(This article belongs to the Section Physical Sensors)

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11 pages, 4225 KiB

Open AccessArticle

Surface Acoustic Waves (SAW)-Based Biosensing for Quantification of Cell Growth in 2D and 3D Cultures

by Tao Wang^1,2,†, Ryan Green^1,3,†, Rajesh Ramakrishnan Nair^1,4,5,†, Mark Howell^1,3, Subhra Mohapatra^1,3,*, Rasim Guldiken^1,2,*

and Shyam Sundar Mohapatra^1,4,*

¹ Center for Research and Education in Nanobioengineering, University of South Florida, Tampa, FL 33612, USA

² Microfluidics and Acoustics Laboratory, Department of Mechanical Engineering, College of Engineering, University of South Florida, Tampa, FL 33612, USA

³ Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA

⁴ Departments of Internal Medicine, University of South Florida, Tampa, FL 33612, USA

⁵ Transgenex Nanobiotech Inc, Tampa, FL 33612, USA

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 32045-32055; https://doi.org/10.3390/s151229909 - 19 Dec 2015

Cited by 43 | Viewed by 12943

Abstract

Detection and quantification of cell viability and growth in two-dimensional (2D) and three-dimensional (3D) cell cultures commonly involve harvesting of cells and therefore requires a parallel set-up of several replicates for time-lapse or dose–response studies. Thus, developing a non-invasive and touch-free detection of [...] Read more.

Detection and quantification of cell viability and growth in two-dimensional (2D) and three-dimensional (3D) cell cultures commonly involve harvesting of cells and therefore requires a parallel set-up of several replicates for time-lapse or dose–response studies. Thus, developing a non-invasive and touch-free detection of cell growth in longitudinal studies of 3D tumor spheroid cultures or of stem cell regeneration remains a major unmet need. Since surface acoustic waves (SAWs) permit mass loading-based biosensing and have been touted due to their many advantages including low cost, small size and ease of assembly, we examined the potential of SAW-biosensing to detect and quantify cell growth. Herein, we demonstrate that a shear horizontal-surface acoustic waves (SH-SAW) device comprising two pairs of resonators consisting of interdigital transducers and reflecting fingers can be used to quantify mass loading by the cells in suspension as well as within a 3D cell culture platform. A 3D COMSOL model was built to simulate the mass loading response of increasing concentrations of cells in suspension in the polydimethylsiloxane (PDMS) well in order to predict the characteristics and optimize the design of the SH-SAW biosensor. The simulated relative frequency shift from the two oscillatory circuit systems (one of which functions as control) were found to be concordant to experimental data generated with RAW264.7 macrophage and A549 cancer cells. In addition, results showed that SAW measurements per se did not affect viability of cells. Further, SH-SAW biosensing was applied to A549 cells cultured on a 3D electrospun nanofiber scaffold that generate tumor spheroids (tumoroids) and the results showed the device's ability to detect changes in tumor spheroid growth over the course of eight days. Taken together, these results demonstrate the use of SH-SAW device for detection and quantification of cell growth changes over time in 2D suspension cultures and in 3D cell culture models, which may have potential applications in both longitudinal 3D cell cultures in cancer biology and in regenerative medicine. Full article

(This article belongs to the Special Issue Micro/Nano Fluidic Devices and Bio-MEMS)

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23 pages, 3356 KiB

Open AccessArticle

Robust Road Condition Detection System Using In-Vehicle Standard Sensors

by Juan Jesús Castillo Aguilar^*

, Juan Antonio Cabrera Carrillo

, Antonio Jesús Guerra Fernández and Enrique Carabias Acosta

Department of Mechanical Engineering, Doctor Ortiz Ramos s/n 29071 Malaga, Spain

Sensors 2015, 15(12), 32056-32078; https://doi.org/10.3390/s151229908 - 19 Dec 2015

Cited by 36 | Viewed by 15250

Abstract

The appearance of active safety systems, such as Anti-lock Braking System, Traction Control System, Stability Control System, etc., represents a major evolution in road safety. In the automotive sector, the term vehicle active safety systems refers to those whose goal is to [...] Read more.

The appearance of active safety systems, such as Anti-lock Braking System, Traction Control System, Stability Control System, etc., represents a major evolution in road safety. In the automotive sector, the term vehicle active safety systems refers to those whose goal is to help avoid a crash or to reduce the risk of having an accident. These systems safeguard us, being in continuous evolution and incorporating new capabilities continuously. In order for these systems and vehicles to work adequately, they need to know some fundamental information: the road condition on which the vehicle is circulating. This early road detection is intended to allow vehicle control systems to act faster and more suitably, thus obtaining a substantial advantage. In this work, we try to detect the road condition the vehicle is being driven on, using the standard sensors installed in commercial vehicles. Vehicle models were programmed in on-board systems to perform real-time estimations of the forces of contact between the wheel and road and the speed of the vehicle. Subsequently, a fuzzy logic block is used to obtain an index representing the road condition. Finally, an artificial neural network was used to provide the optimal slip for each surface. Simulations and experiments verified the proposed method. Full article

(This article belongs to the Special Issue Sensors in New Road Vehicles)

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44 pages, 5851 KiB

Open AccessConcept Paper

Cloud-Based Automated Design and Additive Manufacturing: A Usage Data-Enabled Paradigm Shift

by Dirk Lehmhus^1,†, Thorsten Wuest^2,*,†

, Stefan Wellsandt^3,†, Stefan Bosse^1,4,†

, Toshiya Kaihara^5,†, Klaus-Dieter Thoben^3,6 and Matthias Busse⁷

¹ ISIS Sensorial Materials Scientific Centre, University of Bremen, Bibliothekstraße 1, 28359 Bremen, Germany

² Industrial and Management Systems Engineering Department, Benjamin M. Statler College of Engineering and Mineral Resources, West Virginia University, 333-A Mineral Resource BLDG, Morgantown, WV 26506, USA

³ BIBA—Bremer Institut für Produktion und Logistik GmbH, Hochschulring 20, Bremen 28359, Germany

⁴ Faculty of Mathematics & Computer Science, University of Bremen, Robert Hooke Str. 5, 28359 Bremen, Germany

⁵ Kobe University, Graduate School of Systems Informatics, Department of Systems Sciences, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan

⁶ Faculty of Production Engineering, University of Bremen, Badgasteiner Straße 1, 28359 Bremen, Germany

⁷ Fraunhofer Institute for Manufacturing Technology and Advanced Materials, Wiener Straße 12, 28359 Bremen, Germany

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 32079-32122; https://doi.org/10.3390/s151229905 - 19 Dec 2015

Cited by 64 | Viewed by 17890

Abstract

Integration of sensors into various kinds of products and machines provides access to in-depth usage information as basis for product optimization. Presently, this large potential for more user-friendly and efficient products is not being realized because (a) sensor integration and thus usage information [...] Read more.

Integration of sensors into various kinds of products and machines provides access to in-depth usage information as basis for product optimization. Presently, this large potential for more user-friendly and efficient products is not being realized because (a) sensor integration and thus usage information is not available on a large scale and (b) product optimization requires considerable efforts in terms of manpower and adaptation of production equipment. However, with the advent of cloud-based services and highly flexible additive manufacturing techniques, these obstacles are currently crumbling away at rapid pace. The present study explores the state of the art in gathering and evaluating product usage and life cycle data, additive manufacturing and sensor integration, automated design and cloud-based services in manufacturing. By joining and extrapolating development trends in these areas, it delimits the foundations of a manufacturing concept that will allow continuous and economically viable product optimization on a general, user group or individual user level. This projection is checked against three different application scenarios, each of which stresses different aspects of the underlying holistic concept. The following discussion identifies critical issues and research needs by adopting the relevant stakeholder perspectives. Full article

(This article belongs to the Special Issue Selected Papers from the 2nd International Electronic Conference on Sensors and Applications)

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15 pages, 2732 KiB

Open AccessArticle

Focusing Bistatic FMCW SAR Signal by Range Migration Algorithm Based on Fresnel Approximation

by Yake Li^* and Siu O’Young

Faculty of Engineering and Applied Science, Memorial University of Newfoundland, 230 Elizabeth Avenue, St. John’s, NL A1C5S7, Canada

Sensors 2015, 15(12), 32123-32137; https://doi.org/10.3390/s151229910 - 21 Dec 2015

Cited by 11 | Viewed by 8117

Abstract

Frequency modulated continuous wave (FMCW) technique has recently been employed by synthetic aperture radar (SAR) to decrease the radar cost and volume. However, the operation range is limited by the direct energy leakage from the transmitting channel to receiving channel due to the [...] Read more.

Frequency modulated continuous wave (FMCW) technique has recently been employed by synthetic aperture radar (SAR) to decrease the radar cost and volume. However, the operation range is limited by the direct energy leakage from the transmitting channel to receiving channel due to the operation principle of FMCW technique. Bistatic configuration is an efficient way to increase the isolation between the transmitter and receiver, which could significantly increase the radar standoff range. A bistatic FMCW SAR spectrum model is proposed by using the Fresnel approximation in this paper. This model is similar to that of a monostatic FMCW SAR spectrum, which allows the existing imaging algorithms to be used on bistatic image processing. Based on the new model and the characteristics of FMCW signal, a modified range migration algorithm (RMA) for FMCW SAR is proposed to focus the image, which requires less memory and computational load than the traditional RMA. Point-target simulation is used to verify the proposed spectral model and real data processing verified the effectiveness of the proposed RMA. Full article

(This article belongs to the Section Remote Sensors)

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14 pages, 8234 KiB

Open AccessArticle

Fatigue Crack Length Sizing Using a Novel Flexible Eddy Current Sensor Array

by Ruifang Xie^*, Dixiang Chen, Mengchun Pan, Wugang Tian, Xuezhong Wu, Weihong Zhou and Ying Tang

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

Sensors 2015, 15(12), 32138-32151; https://doi.org/10.3390/s151229911 - 21 Dec 2015

Cited by 70 | Viewed by 10558

Abstract

The eddy current probe, which is flexible, array typed, highly sensitive and capable of quantitative inspection is one practical requirement in nondestructive testing and also a research hotspot. A novel flexible planar eddy current sensor array for the inspection of microcrack presentation in [...] Read more.

The eddy current probe, which is flexible, array typed, highly sensitive and capable of quantitative inspection is one practical requirement in nondestructive testing and also a research hotspot. A novel flexible planar eddy current sensor array for the inspection of microcrack presentation in critical parts of airplanes is developed in this paper. Both exciting and sensing coils are etched on polyimide films using a flexible printed circuit board technique, thus conforming the sensor to complex geometric structures. In order to serve the needs of condition-based maintenance (CBM), the proposed sensor array is comprised of 64 elements. Its spatial resolution is only 0.8 mm, and it is not only sensitive to shallow microcracks, but also capable of sizing the length of fatigue cracks. The details and advantages of our sensor design are introduced. The working principal and the crack responses are analyzed by finite element simulation, with which a crack length sizing algorithm is proposed. Experiments based on standard specimens are implemented to verify the validity of our simulation and the efficiency of the crack length sizing algorithm. Experimental results show that the sensor array is sensitive to microcracks, and is capable of crack length sizing with an accuracy within ±0.2 mm. Full article

(This article belongs to the Section Physical Sensors)

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16 pages, 5381 KiB

Open AccessArticle

A TSR Visual Servoing System Based on a Novel Dynamic Template Matching Method

by Jia Cai^1,2, Panfeng Huang^1,2,*, Bin Zhang^1,2 and Dongke Wang^1,2

¹ National Key Laboratory of Aerospace Flight Dynamics, Northwestern Polytechnical University, 710072 Xi’an, China

² Research Center for Intelligent Robotics, School of Astronautics, Northwestern Polytechnical University, 710072 Xi’an, China

Sensors 2015, 15(12), 32152-32167; https://doi.org/10.3390/s151229884 - 21 Dec 2015

Cited by 24 | Viewed by 7300

Abstract

The so-called Tethered Space Robot (TSR) is a novel active space debris removal system. To solve its problem of non-cooperative target recognition during short-distance rendezvous events, this paper presents a framework for a real-time visual servoing system using non-calibrated monocular-CMOS (Complementary Metal Oxide [...] Read more.

The so-called Tethered Space Robot (TSR) is a novel active space debris removal system. To solve its problem of non-cooperative target recognition during short-distance rendezvous events, this paper presents a framework for a real-time visual servoing system using non-calibrated monocular-CMOS (Complementary Metal Oxide Semiconductor). When a small template is used for matching with a large scene, it always leads to mismatches, so a novel template matching algorithm to solve the problem is presented. Firstly, the novel matching algorithm uses a hollow annulus structure according to a FAST (Features from Accelerated Segment) algorithm and makes the method be rotation-invariant. Furthermore, the accumulative deviation can be decreased by the hollow structure. The matching function is composed of grey and gradient differences between template and object image, which help it reduce the effects of illumination and noises. Then, a dynamic template update strategy is designed to avoid tracking failures brought about by wrong matching or occlusion. Finally, the system synthesizes the least square integrated predictor, realizing tracking online in complex circumstances. The results of ground experiments show that the proposed algorithm can decrease the need for sophisticated computation and improves matching accuracy. Full article

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

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20 pages, 4257 KiB

Open AccessArticle

Design, Implementation and Evaluation of an Indoor Navigation System for Visually Impaired People

by Alejandro Santos Martinez-Sala^*, Fernando Losilla^†

, Juan Carlos Sánchez-Aarnoutse^† and Joan García-Haro^†

¹ Department of Information and Communication Technologies, Universidad Politécnica de Cartagena, Campus Muralla del Mar, Cartagena E-30202, Spain

^† These authors contributed equally to this work.

Sensors 2015, 15(12), 32168-32187; https://doi.org/10.3390/s151229912 - 21 Dec 2015

Cited by 80 | Viewed by 12157

Abstract

Indoor navigation is a challenging task for visually impaired people. Although there are guidance systems available for such purposes, they have some drawbacks that hamper their direct application in real-life situations. These systems are either too complex, inaccurate, or require very special conditions [...] Read more.

Indoor navigation is a challenging task for visually impaired people. Although there are guidance systems available for such purposes, they have some drawbacks that hamper their direct application in real-life situations. These systems are either too complex, inaccurate, or require very special conditions (i.e., rare in everyday life) to operate. In this regard, Ultra-Wideband (UWB) technology has been shown to be effective for indoor positioning, providing a high level of accuracy and low installation complexity. This paper presents SUGAR, an indoor navigation system for visually impaired people which uses UWB for positioning, a spatial database of the environment for pathfinding through the application of the A* algorithm, and a guidance module. The interaction with the user takes place using acoustic signals and voice commands played through headphones. The suitability of the system for indoor navigation has been verified by means of a functional and usable prototype through a field test with a blind person. In addition, other tests have been conducted in order to show the accuracy of different relevant parts of the system. Full article

(This article belongs to the Special Issue Sensors for Indoor Mapping and Navigation)

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25 pages, 8698 KiB

Open AccessArticle

Far-Infrared Based Pedestrian Detection for Driver-Assistance Systems Based on Candidate Filters, Gradient-Based Feature and Multi-Frame Approval Matching

by Guohua Wang

and Qiong Liu^*

School of Software Engineering, South China University of Technology, No. 382 Waihuan East Rd., Guangzhou 510006, China

Sensors 2015, 15(12), 32188-32212; https://doi.org/10.3390/s151229874 - 21 Dec 2015

Cited by 19 | Viewed by 8855

Abstract

Far-infrared pedestrian detection approaches for advanced driver-assistance systems based on high-dimensional features fail to simultaneously achieve robust and real-time detection. We propose a robust and real-time pedestrian detection system characterized by novel candidate filters, novel pedestrian features and multi-frame approval matching in a [...] Read more.

Far-infrared pedestrian detection approaches for advanced driver-assistance systems based on high-dimensional features fail to simultaneously achieve robust and real-time detection. We propose a robust and real-time pedestrian detection system characterized by novel candidate filters, novel pedestrian features and multi-frame approval matching in a coarse-to-fine fashion. Firstly, we design two filters based on the pedestrians’ head and the road to select the candidates after applying a pedestrian segmentation algorithm to reduce false alarms. Secondly, we propose a novel feature encapsulating both the relationship of oriented gradient distribution and the code of oriented gradient to deal with the enormous variance in pedestrians’ size and appearance. Thirdly, we introduce a multi-frame approval matching approach utilizing the spatiotemporal continuity of pedestrians to increase the detection rate. Large-scale experiments indicate that the system works in real time and the accuracy has improved about 9% compared with approaches based on high-dimensional features only. Full article

(This article belongs to the Special Issue Sensors in New Road Vehicles)

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Sensors, Volume 15, Issue 12 (December 2015) – 145 articles

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