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Open AccessArticle Sensing Responses Based on Transfer Characteristics of InAs Nanowire Field-Effect Transistors

by Alex C. Tseng, David Lynall, Igor Savelyev, Marina Blumin, Shiliang Wang and Harry E. Ruda

Sensors 2017, 17(7), 1640; doi:10.3390/s17071640 (registering DOI)

Received: 1 June 2017 / Revised: 1 July 2017 / Accepted: 13 July 2017 / Published: 16 July 2017

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Abstract

Nanowire-based field-effect transistors (FETs) have demonstrated considerable promise for a new generation of chemical and biological sensors. Indium arsenide (InAs), by virtue of its high electron mobility and intrinsic surface accumulation layer of electrons, holds properties beneficial for creating high performance sensors that

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Nanowire-based field-effect transistors (FETs) have demonstrated considerable promise for a new generation of chemical and biological sensors. Indium arsenide (InAs), by virtue of its high electron mobility and intrinsic surface accumulation layer of electrons, holds properties beneficial for creating high performance sensors that can be used in applications such as point-of-care testing for patients diagnosed with chronic diseases. Here, we propose devices based on a parallel configuration of InAs nanowires and investigate sensor responses from measurements of conductance over time and FET characteristics. The devices were tested in controlled concentrations of vapour containing acetic acid, 2-butanone and methanol. After adsorption of analyte molecules, trends in the transient current and transfer curves are correlated with the nature of the surface interaction. Specifically, we observed proportionality between acetic acid concentration and relative conductance change, off current and surface charge density extracted from subthreshold behaviour. We suggest the origin of the sensing response to acetic acid as a two-part, reversible acid-base and redox reaction between acetic acid, InAs and its native oxide that forms slow, donor-like states at the nanowire surface. We further describe a simple model that is able to distinguish the occurrence of physical versus chemical adsorption by comparing the values of the extracted surface charge density. These studies demonstrate that InAs nanowires can produce a multitude of sensor responses for the purpose of developing next generation, multi-dimensional sensor applications. Full article

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

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Open AccessArticle Electrochemical Flow-ELISA for Rapid and Sensitive Determination of Microcystin-LR Using Automated Sequential Injection System

by Lesedi Lebogang, Jongjit Jantra, Martin Hedström and Bo Mattiasson

Sensors 2017, 17(7), 1639; doi:10.3390/s17071639 (registering DOI)

Received: 6 June 2017 / Revised: 30 June 2017 / Accepted: 5 July 2017 / Published: 16 July 2017

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Abstract

An amperometric immunoanalysis system based on monoclonal antibodies immobilized on Sepharose beads and packed into a micro-immunocolumn was developed for the quantification of microcystin-LR. Microcystin-LR (MCLR) was used as a reference microcystin variant. Inside the immunocolumn, free microcystins and microcystin-horseradish peroxidase (tracer) were

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An amperometric immunoanalysis system based on monoclonal antibodies immobilized on Sepharose beads and packed into a micro-immunocolumn was developed for the quantification of microcystin-LR. Microcystin-LR (MCLR) was used as a reference microcystin variant. Inside the immunocolumn, free microcystins and microcystin-horseradish peroxidase (tracer) were sequentially captured by the immobilized antibodies, and the detection was performed electrochemically using Super AquaBlue ELISA substrate 2,2′-azinobis(3-ethylbenzothiazoline-sulfonic acid) (ABTS). The ABTS^●+ generated by enzymatic oxidation of ABTS was electrochemically determined at a carbon working electrode by applying a reduction potential set at 0.4 V versus Ag/AgCl reference electrode. The peak current intensity was inversely proportional to the amount of analyte bound to the immunocolumn. The amperometric flow-ELISA system, which was automatically controlled through the CapSenze^TM (Lund, Sweden) computer software, enabled determination of MCLR as low as 0.01 µg/L. The assay time was very short (20 min for one assay cycle). In addition, the electrochemical signals were not significantly affected by possible interferences which could be present in the real samples. Along with the simplicity of automation, this makes the developed method a promising tool for use in water quality assessment. Full article

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

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Open AccessArticle Frame Transmission Efficiency-Based Cross-Layer Congestion Notification Scheme in Wireless Ad Hoc Networks

by Huaguang He, Taoshen Li, Luting Feng and Jin Ye

Sensors 2017, 17(7), 1637; doi:10.3390/s17071637 (registering DOI)

Received: 26 April 2017 / Revised: 1 July 2017 / Accepted: 11 July 2017 / Published: 15 July 2017

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Abstract

Different from the traditional wired network, the fundamental cause of transmission congestion in wireless ad hoc networks is medium contention. How to utilize the congestion state from the MAC (Media Access Control) layer to adjust the transmission rate is core work for transport

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Different from the traditional wired network, the fundamental cause of transmission congestion in wireless ad hoc networks is medium contention. How to utilize the congestion state from the MAC (Media Access Control) layer to adjust the transmission rate is core work for transport protocol design. However, recent works have shown that the existing cross-layer congestion detection solutions are too complex to be deployed or not able to characterize the congestion accurately. We first propose a new congestion metric called frame transmission efficiency (i.e., the ratio of successful transmission delay to the frame service delay), which describes the medium contention in a fast and accurate manner. We further present the design and implementation of RECN (ECN and the ratio of successful transmission delay to the frame service delay in the MAC layer, namely, the frame transmission efficiency), a general supporting scheme that adjusts the transport sending rate through a standard ECN (Explicit Congestion Notification) signaling method. Our method can be deployed on commodity switches with small firmware updates, while making no modification on end hosts. We integrate RECN transparently (i.e., without modification) with TCP on NS2 simulation. The experimental results show that RECN remarkably improves network goodput across multiple concurrent TCP flows. Full article

(This article belongs to the Section Sensor Networks)

Open AccessArticle Development of Three-Dimensional Dental Scanning Apparatus Using Structured Illumination

by Jae Sung Ahn, Anjin Park, Ju Wan Kim, Byeong Ha Lee and Joo Beom Eom

Sensors 2017, 17(7), 1634; doi:10.3390/s17071634 (registering DOI)

Received: 19 June 2017 / Revised: 10 July 2017 / Accepted: 12 July 2017 / Published: 15 July 2017

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Abstract

We demonstrated a three-dimensional (3D) dental scanning apparatus based on structured illumination. A liquid lens was used for tuning focus and a piezomotor stage was used for the shift of structured light. A simple algorithm, which detects intensity modulation, was used to perform

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We demonstrated a three-dimensional (3D) dental scanning apparatus based on structured illumination. A liquid lens was used for tuning focus and a piezomotor stage was used for the shift of structured light. A simple algorithm, which detects intensity modulation, was used to perform optical sectioning with structured illumination. We reconstructed a 3D point cloud, which represents the 3D coordinates of the digitized surface of a dental gypsum cast by piling up sectioned images. We performed 3D registration of an individual 3D point cloud, which includes alignment and merging the 3D point clouds to exhibit a 3D model of the dental cast. Full article

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

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Open AccessArticle Localization with Graph Diffusion Property

by Pengpeng Chen, Yuqing Yin, Shouwan Gao, Qiang Niu and Jun Gu

Sensors 2017, 17(7), 1636; doi:10.3390/s17071636 (registering DOI)

Received: 10 May 2017 / Revised: 5 July 2017 / Accepted: 14 July 2017 / Published: 15 July 2017

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Abstract

Node localization is an essential issue in wireless sensor networks (WSNs). Many range-free localization methods have been proposed to satisfy the requirement of low-system cost. However, some range-free methods only depend on network connectivity, and others only utilize the proximity information attached in

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Node localization is an essential issue in wireless sensor networks (WSNs). Many range-free localization methods have been proposed to satisfy the requirement of low-system cost. However, some range-free methods only depend on network connectivity, and others only utilize the proximity information attached in neighborhood ordering. To employ the strength of the above two aspects, this paper introduces a new metric system called Combined and Weighted Diffusion Distance (CWDD). CWDD is designed to obtain the relative distance among nodes based on both graph diffusion property and neighbor information. We implement our design by embedding CWDD into two well-known localization algorithms and evaluate it by extensive simulations. Results show that our design improves the localization performance in large scale and non-uniform sensor networks, which reduces positioning errors by as much as 26%. Full article

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

Open AccessTechnical Note Flexible Boron-Doped Diamond (BDD) Electrodes for Plant Monitoring

by Shoko Tago, Tsuyoshi Ochiai, Seitaro Suzuki, Mio Hayashi, Takeshi Kondo and Akira Fujishima

Sensors 2017, 17(7), 1638; doi:10.3390/s17071638 (registering DOI)

Received: 17 June 2017 / Revised: 7 July 2017 / Accepted: 13 July 2017 / Published: 15 July 2017

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Abstract

Detecting the bio-potential changes of plants would be useful for monitoring their growth and health in the field. A sensitive plant monitoring system with flexible boron-doped diamond (BDD) electrodes prepared from BDD powder and resin (Nafion or Vylon-KE1830) was investigated. The properties of

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Detecting the bio-potential changes of plants would be useful for monitoring their growth and health in the field. A sensitive plant monitoring system with flexible boron-doped diamond (BDD) electrodes prepared from BDD powder and resin (Nafion or Vylon-KE1830) was investigated. The properties of the electrodes were compared with those of small BDD plate-type electrodes by monitoring the bioelectric potentials of potted Aloe and hybrid species in the genus Opuntia. While flexible BDD electrodes have wide potential windows, their cyclic voltammograms are different from those of the BDD plate. Further, the potential gap between a pair of electrodes attached to the plants changes as the plants are stimulated artificially with a finger touch, suggesting that the bioelectric potentials in the plant also changed, manifesting as changes in the potential gap between the electrodes. The BDD electrodes were assessed for their response reproducibility to a finger stimulus for 30 days. It was concluded that the plant monitoring system worked well with flexible BDD electrodes. Further, the electrodes were stable, and as reliable as the BDD plate electrodes in this study. Thus, a flexible and inexpensive BDD electrode system was successfully fabricated for monitoring the bioelectric potential changes in plants. Full article

(This article belongs to the Special Issue Advanced Sensors Based on Carbon Electrodes)

Open AccessArticle Passive Downhole Pressure Sensor Based on Surface Acoustic Wave Technology

by Sully M. M. Quintero, Sávio W. O. Figueiredo, Victor L. Takahashi, Roberth A. W. Llerena and Arthur M. B. Braga

Sensors 2017, 17(7), 1635; doi:10.3390/s17071635 (registering DOI)

Received: 20 June 2017 / Revised: 12 July 2017 / Accepted: 13 July 2017 / Published: 15 July 2017

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Abstract

A passive surface acoustic wave (SAW) pressure sensor was developed for real-time pressure monitoring in downhole application. The passive pressure sensor consists of a SAW resonator, which is attached to a circular metal diaphragm used as a pressure transducer. While the membrane deflects

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A passive surface acoustic wave (SAW) pressure sensor was developed for real-time pressure monitoring in downhole application. The passive pressure sensor consists of a SAW resonator, which is attached to a circular metal diaphragm used as a pressure transducer. While the membrane deflects as a function of pressure applied, the frequency response changes due to the variation of the SAW propagation parameters. The sensitivity and linearity of the SAW pressure sensor were measured to be 8.3 kHz/bar and 0.999, respectively. The experimental results were validated with a hybrid analytical–numerical analysis. The good results combined with the robust design and packaging for harsh environment demonstrated it to be a promising sensor for industrial applications. Full article

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

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Open AccessArticle A Multiscale Approach to the Smart Deployment of Micro-Sensors over Lightweight Structures

by Giovanni Capellari, Francesco Caimmi, Matteo Bruggi and Stefano Mariani

Sensors 2017, 17(7), 1632; doi:10.3390/s17071632 (registering DOI)

Received: 7 April 2017 / Revised: 7 July 2017 / Accepted: 13 July 2017 / Published: 15 July 2017

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Abstract

A topology optimization approach has been recently proposed to maximize the sensitivity to damage of measurements, collected through a network of sensors to be deployed over thin plates for structural health monitoring purposes. Within such a frame, damage is meant as a change

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A topology optimization approach has been recently proposed to maximize the sensitivity to damage of measurements, collected through a network of sensors to be deployed over thin plates for structural health monitoring purposes. Within such a frame, damage is meant as a change in the structural health characterized by a reduction of relevant stiffness and load-carrying properties. The sensitivity to a damage of unknown amplitude and location is computed by comparing the response to the external actions of the healthy structure and of a set of auxiliary damaged structures, each one featuring reduced mechanical properties in a small region only. The topology optimization scheme has been devised to properly account for the information coming from all of the sensors to be placed on the structure and for damage depending on its location. In this work, we extend the approach within a multiscale frame to account for three different length scales: a macroscopic one, linked to the dimensions of the whole structure to be monitored; a mesoscopic one, linked to the characteristic size of the damaged region; a microscopic one, linked to the size of inertial microelectromechanical systems (MEMS) to be used within a marginally-invasive health monitoring system. Results are provided for a square plate and for a section of fuselage with stiffeners, to show how the micro-sensors have to be deployed to maximize the capability to detect a damage, to assess the sensitivity of the results to the measurement noise and to also discuss the speedup in designing the network topology against a standard single-scale approach. Full article

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

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Open AccessArticle Non-Convex Sparse and Low-Rank Based Robust Subspace Segmentation for Data Mining

by Wenlong Cheng, Mingbo Zhao, Naixue Xiong and Kwok Tai Chui

Sensors 2017, 17(7), 1633; doi:10.3390/s17071633 (registering DOI)

Received: 16 June 2017 / Revised: 8 July 2017 / Accepted: 10 July 2017 / Published: 15 July 2017

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Abstract

Parsimony, including sparsity and low-rank, has shown great importance for data mining in social networks, particularly in tasks such as segmentation and recognition. Traditionally, such modeling approaches rely on an iterative algorithm that minimizes an objective function with convex l₁-norm or

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Parsimony, including sparsity and low-rank, has shown great importance for data mining in social networks, particularly in tasks such as segmentation and recognition. Traditionally, such modeling approaches rely on an iterative algorithm that minimizes an objective function with convex l₁-norm or nuclear norm constraints. However, the obtained results by convex optimization are usually suboptimal to solutions of original sparse or low-rank problems. In this paper, a novel robust subspace segmentation algorithm has been proposed by integrating l_p-norm and Schatten p-norm constraints. Our so-obtained affinity graph can better capture local geometrical structure and the global information of the data. As a consequence, our algorithm is more generative, discriminative and robust. An efficient linearized alternating direction method is derived to realize our model. Extensive segmentation experiments are conducted on public datasets. The proposed algorithm is revealed to be more effective and robust compared to five existing algorithms. Full article

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

Open AccessArticle Design and Implementation of a Smart Home System Using Multisensor Data Fusion Technology

by Yu-Liang Hsu, Po-Huan Chou, Hsing-Cheng Chang, Shyan-Lung Lin, Shih-Chin Yang, Heng-Yi Su, Chih-Chien Chang, Yuan-Sheng Cheng and Yu-Chen Kuo

Sensors 2017, 17(7), 1631; doi:10.3390/s17071631 (registering DOI)

Received: 16 June 2017 / Revised: 10 July 2017 / Accepted: 11 July 2017 / Published: 15 July 2017

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Abstract

This paper aims to develop a multisensor data fusion technology-based smart home system by integrating wearable intelligent technology, artificial intelligence, and sensor fusion technology. We have developed the following three systems to create an intelligent smart home environment: (1) a wearable motion sensing

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This paper aims to develop a multisensor data fusion technology-based smart home system by integrating wearable intelligent technology, artificial intelligence, and sensor fusion technology. We have developed the following three systems to create an intelligent smart home environment: (1) a wearable motion sensing device to be placed on residents’ wrists and its corresponding 3D gesture recognition algorithm to implement a convenient automated household appliance control system; (2) a wearable motion sensing device mounted on a resident’s feet and its indoor positioning algorithm to realize an effective indoor pedestrian navigation system for smart energy management; (3) a multisensor circuit module and an intelligent fire detection and alarm algorithm to realize a home safety and fire detection system. In addition, an intelligent monitoring interface is developed to provide in real-time information about the smart home system, such as environmental temperatures, CO concentrations, communicative environmental alarms, household appliance status, human motion signals, and the results of gesture recognition and indoor positioning. Furthermore, an experimental testbed for validating the effectiveness and feasibility of the smart home system was built and verified experimentally. The results showed that the 3D gesture recognition algorithm could achieve recognition rates for automated household appliance control of 92.0%, 94.8%, 95.3%, and 87.7% by the 2-fold cross-validation, 5-fold cross-validation, 10-fold cross-validation, and leave-one-subject-out cross-validation strategies. For indoor positioning and smart energy management, the distance accuracy and positioning accuracy were around 0.22% and 3.36% of the total traveled distance in the indoor environment. For home safety and fire detection, the classification rate achieved 98.81% accuracy for determining the conditions of the indoor living environment. Full article

(This article belongs to the Special Issue Selected Papers from IEEE ICASI 2017)

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Open AccessArticle A Label-Free Fluorescent Array Sensor Utilizing Liposome Encapsulating Calcein for Discriminating Target Proteins by Principal Component Analysis

by Ryota Imamura, Naoki Murata, Toshinori Shimanouchi, Kaoru Yamashita, Masayuki Fukuzawa and Minoru Noda

Sensors 2017, 17(7), 1630; doi:10.3390/s17071630 (registering DOI)

Received: 16 May 2017 / Revised: 5 July 2017 / Accepted: 13 July 2017 / Published: 15 July 2017

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Abstract

A new fluorescent arrayed biosensor has been developed to discriminate species and concentrations of target proteins by using plural different phospholipid liposome species encapsulating fluorescent molecules, utilizing differences in permeation of the fluorescent molecules through the membrane to modulate liposome-target protein interactions. This

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A new fluorescent arrayed biosensor has been developed to discriminate species and concentrations of target proteins by using plural different phospholipid liposome species encapsulating fluorescent molecules, utilizing differences in permeation of the fluorescent molecules through the membrane to modulate liposome-target protein interactions. This approach proposes a basically new label-free fluorescent sensor, compared with the common technique of developed fluorescent array sensors with labeling. We have confirmed a high output intensity of fluorescence emission related to characteristics of the fluorescent molecules dependent on their concentrations when they leak from inside the liposomes through the perturbed lipid membrane. After taking an array image of the fluorescence emission from the sensor using a CMOS imager, the output intensities of the fluorescence were analyzed by a principal component analysis (PCA) statistical method. It is found from PCA plots that different protein species with several concentrations were successfully discriminated by using the different lipid membranes with high cumulative contribution ratio. We also confirmed that the accuracy of the discrimination by the array sensor with a single shot is higher than that of a single sensor with multiple shots. Full article

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

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Open AccessArticle A Pulse Rate Detection Method for Mouse Application Based on Multi-PPG Sensors

by Shu-Tyng Lin, Wei-Hao Chen and Yuan-Hsiang Lin

Sensors 2017, 17(7), 1628; doi:10.3390/s17071628 (registering DOI)

Received: 7 May 2017 / Revised: 26 June 2017 / Accepted: 11 July 2017 / Published: 14 July 2017

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Abstract

Heart rate is an important physiological parameter for healthcare. Among measurement methods, photoplethysmography (PPG) is an easy and convenient method for pulse rate detection. However, as the PPG signal faces the challenge of motion artifacts and is constrained by the position chosen, the

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Heart rate is an important physiological parameter for healthcare. Among measurement methods, photoplethysmography (PPG) is an easy and convenient method for pulse rate detection. However, as the PPG signal faces the challenge of motion artifacts and is constrained by the position chosen, the purpose of this paper is to implement a comfortable and easy-to-use multi-PPG sensor module combined with a stable and accurate real-time pulse rate detection method on a computer mouse. A weighted average method for multi-PPG sensors is used to adjust the weight of each signal channel in order to raise the accuracy and stability of the detected signal, therefore reducing the disturbance of noise under the environment of moving effectively and efficiently. According to the experiment results, the proposed method can increase the usability and probability of PPG signal detection on palms. Full article

(This article belongs to the Special Issue Advanced Physiological Sensing)

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Open AccessArticle Real-Time Communication Support for Underwater Acoustic Sensor Networks ^†

by Rodrigo Santos, Javier Orozco, Matias Micheletto, Sergio F. Ochoa, Roc Meseguer, Pere Millan and and Carlos Molina

Sensors 2017, 17(7), 1629; doi:10.3390/s17071629 (registering DOI)

Received: 15 May 2017 / Revised: 6 July 2017 / Accepted: 6 July 2017 / Published: 14 July 2017

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Abstract

Underwater sensor networks represent an important and promising field of research due to the large diversity of underwater ubiquitous applications that can be supported by these networks, e.g., systems that deliver tsunami and oil spill warnings, or monitor submarine ecosystems. Most of these

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Underwater sensor networks represent an important and promising field of research due to the large diversity of underwater ubiquitous applications that can be supported by these networks, e.g., systems that deliver tsunami and oil spill warnings, or monitor submarine ecosystems. Most of these monitoring and warning systems require real-time communication in wide area networks that have a low density of nodes. The underwater communication medium involved in these networks is very harsh and imposes strong restrictions to the communication process. In this scenario, the real-time transmission of information is done mainly using acoustic signals, since the network nodes are not physically close. The features of the communication scenario and the requirements of the communication process represent major challenges for designers of both, communication protocols and monitoring and warning systems. The lack of models to represent these networks is the main stumbling block for the proliferation of underwater ubiquitous systems. This paper presents a real-time communication model for underwater acoustic sensor networks (UW-ASN) that are designed to cover wide areas with a low density of nodes, using any-to-any communication. This model is analytic, considers two solution approaches for scheduling the real-time messages, and provides a time-constraint analysis for the network performance. Using this model, the designers of protocols and underwater ubiquitous systems can quickly prototype and evaluate their solutions in an evolving way, in order to determine the best solution to the problem being addressed. The suitability of the proposal is illustrated with a case study that shows the performance of a UW-ASN under several initial conditions. This is the first analytic model for representing real-time communication in this type of network, and therefore, it opens the door for the development of underwater ubiquitous systems for several application scenarios. Full article

(This article belongs to the Special Issue Selected Papers from UCAmI 2016)

Open AccessArticle Phenoliner: A New Field Phenotyping Platform for Grapevine Research

by Anna Kicherer, Katja Herzog, Nele Bendel, Hans-Christian Klück, Andreas Backhaus, Markus Wieland, Johann Christian Rose, Lasse Klingbeil, Thomas Läbe, Christian Hohl, Willi Petry, Heiner Kuhlmann, Udo Seiffert and Reinhard Töpfer

Sensors 2017, 17(7), 1625; doi:10.3390/s17071625 (registering DOI)

Received: 3 May 2017 / Revised: 23 June 2017 / Accepted: 11 July 2017 / Published: 14 July 2017

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Abstract

In grapevine research the acquisition of phenotypic data is largely restricted to the field due to its perennial nature and size. The methodologies used to assess morphological traits and phenology are mainly limited to visual scoring. Some measurements for biotic and abiotic stress,

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In grapevine research the acquisition of phenotypic data is largely restricted to the field due to its perennial nature and size. The methodologies used to assess morphological traits and phenology are mainly limited to visual scoring. Some measurements for biotic and abiotic stress, as well as for quality assessments, are done by invasive measures. The new evolving sensor technologies provide the opportunity to perform non-destructive evaluations of phenotypic traits using different field phenotyping platforms. One of the biggest technical challenges for field phenotyping of grapevines are the varying light conditions and the background. In the present study the Phenoliner is presented, which represents a novel type of a robust field phenotyping platform. The vehicle is based on a grape harvester following the concept of a moveable tunnel. The tunnel it is equipped with different sensor systems (RGB and NIR camera system, hyperspectral camera, RTK-GPS, orientation sensor) and an artificial broadband light source. It is independent from external light conditions and in combination with artificial background, the Phenoliner enables standardised acquisition of high-quality, geo-referenced sensor data. Full article

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

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Open AccessArticle Mechanomyography and Torque during FES-Evoked Muscle Contractions to Fatigue in Individuals with Spinal Cord Injury

by Nor Zainah Mohamad, Nur Azah Hamzaid, Glen M. Davis, Ahmad Khairi Abdul Wahab and Nazirah Hasnan

Sensors 2017, 17(7), 1627; doi:10.3390/s17071627 (registering DOI)

Received: 5 January 2017 / Revised: 5 April 2017 / Accepted: 12 April 2017 / Published: 14 July 2017

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Abstract

A mechanomyography muscle contraction (MC) sensor, affixed to the skin surface, was used to quantify muscle tension during repetitive functional electrical stimulation (FES)-evoked isometric rectus femoris contractions to fatigue in individuals with spinal cord injury (SCI). Nine persons with motor complete SCI were

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A mechanomyography muscle contraction (MC) sensor, affixed to the skin surface, was used to quantify muscle tension during repetitive functional electrical stimulation (FES)-evoked isometric rectus femoris contractions to fatigue in individuals with spinal cord injury (SCI). Nine persons with motor complete SCI were seated on a commercial muscle dynamometer that quantified peak torque and average torque outputs, while measurements from the MC sensor were simultaneously recorded. MC-sensor-predicted measures of dynamometer torques, including the signal peak (SP) and signal average (SA), were highly associated with isometric knee extension peak torque (SP: r = 0.91, p < 0.0001), and average torque (SA: r = 0.89, p < 0.0001), respectively. Bland-Altman (BA) analyses with Lin’s concordance (ρ_C) revealed good association between MC-sensor-predicted peak muscle torques (SP; ρ_C = 0.91) and average muscle torques (SA; ρ_C = 0.89) with the equivalent dynamometer measures, over a range of FES current amplitudes. The relationship of dynamometer torques and predicted MC torques during repetitive FES-evoked muscle contraction to fatigue were moderately associated (SP: r = 0.80, p < 0.0001; SA: r = 0.77; p < 0.0001), with BA associations between the two devices fair-moderate (SP; ρ_C = 0.70: SA; ρ_C = 0.30). These findings demonstrated that a skin-surface muscle mechanomyography sensor was an accurate proxy for electrically-evoked muscle contraction torques when directly measured during isometric dynamometry in individuals with SCI. The novel application of the MC sensor during FES-evoked muscle contractions suggested its possible application for real-world tasks (e.g., prolonged sit-to-stand, stepping,) where muscle forces during fatiguing activities cannot be directly measured. Full article

(This article belongs to the Section Biosensors)

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Open AccessArticle Enhanced Handover Decision Algorithm in Heterogeneous Wireless Network

by Radhwan Mohamed Abdullah and Zuriati Ahmad Zukarnain

Sensors 2017, 17(7), 1626; doi:10.3390/s17071626 (registering DOI)

Received: 25 May 2017 / Revised: 23 June 2017 / Accepted: 29 June 2017 / Published: 14 July 2017

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Abstract

Transferring a huge amount of data between different network locations over the network links depends on the network’s traffic capacity and data rate. Traditionally, a mobile device may be moved to achieve the operations of vertical handover, considering only one criterion, that is

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Transferring a huge amount of data between different network locations over the network links depends on the network’s traffic capacity and data rate. Traditionally, a mobile device may be moved to achieve the operations of vertical handover, considering only one criterion, that is the Received Signal Strength (RSS). The use of a single criterion may cause service interruption, an unbalanced network load and an inefficient vertical handover. In this paper, we propose an enhanced vertical handover decision algorithm based on multiple criteria in the heterogeneous wireless network. The algorithm consists of three technology interfaces: Long-Term Evolution (LTE), Worldwide interoperability for Microwave Access (WiMAX) and Wireless Local Area Network (WLAN). It also employs three types of vertical handover decision algorithms: equal priority, mobile priority and network priority. The simulation results illustrate that the three types of decision algorithms outperform the traditional network decision algorithm in terms of handover number probability and the handover failure probability. In addition, it is noticed that the network priority handover decision algorithm produces better results compared to the equal priority and the mobile priority handover decision algorithm. Finally, the simulation results are validated by the analytical model. Full article

(This article belongs to the Section Sensor Networks)

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Open AccessArticle Novel Selective Detection Method of Tumor Angiogenesis Factors Using Living Nano-Robots

by Mohamed Al-Fandi, Nida Alshraiedeh, Rami Owies, Hala Alshdaifat, Omamah Al-Mahaseneh, Khadijah Al-Tall and Rawan Alawneh

Sensors 2017, 17(7), 1580; doi:10.3390/s17071580 (registering DOI)

Received: 8 May 2017 / Revised: 24 June 2017 / Accepted: 1 July 2017 / Published: 14 July 2017

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Abstract

This paper reports a novel self-detection method for tumor cells using living nano-robots. These living robots are a nonpathogenic strain of E. coli bacteria equipped with naturally synthesized bio-nano-sensory systems that have an affinity to VEGF, an angiogenic factor overly-expressed by cancer cells.

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This paper reports a novel self-detection method for tumor cells using living nano-robots. These living robots are a nonpathogenic strain of E. coli bacteria equipped with naturally synthesized bio-nano-sensory systems that have an affinity to VEGF, an angiogenic factor overly-expressed by cancer cells. The VEGF-affinity/chemotaxis was assessed using several assays including the capillary chemotaxis assay, chemotaxis assay on soft agar, and chemotaxis assay on solid agar. In addition, a microfluidic device was developed to possibly discover tumor cells through the overexpressed vascular endothelial growth factor (VEGF). Various experiments to study the sensing characteristic of the nano-robots presented a strong response toward the VEGF. Thus, a new paradigm of selective targeting therapies for cancer can be advanced using swimming E. coli as self-navigator miniaturized robots as well as drug-delivery vehicles. Full article

(This article belongs to the Special Issue Biosensors for Cancer Biomarkers)

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Open AccessArticle A Wi-Fi Union Mechanism for Internet Advertising Reciprocal Platform in Microenterprises

by Thi Thanh An Nguyen, Che-Pin Chang and Shyan-Ming Yuan

Sensors 2017, 17(7), 1617; doi:10.3390/s17071617

Received: 26 May 2017 / Revised: 8 July 2017 / Accepted: 10 July 2017 / Published: 13 July 2017

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Abstract

With the evolution of the Internet and smartphone devices, Internet advertising has become one of the most important methods for delivering promotional marketing messages to customers. However, the efficiency of Internet advertising for microenterprise is not very high, since Wi-Fi advertising—which is limited

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With the evolution of the Internet and smartphone devices, Internet advertising has become one of the most important methods for delivering promotional marketing messages to customers. However, the efficiency of Internet advertising for microenterprise is not very high, since Wi-Fi advertising—which is limited by a small router coverage area—is mainly used. Moreover, because of the lack of money, microenterprises have been using low-cost methods to promote their products. Thus, enhancing the effectiveness of Wi-Fi advertising, and solving the problem of cost and the range of the views are now an essential investigation in this study. In this paper, we propose a reciprocal model with Wi-Fi union mechanism for Internet advertising based on fog computing architecture to enhance the efficiency of advertisement, reduce the cost, and increase the range of the views for microenterprise by using the Internet. In particular, the system was built in advertisers’, publishers’, and consumers’ sides. In our system, we use contribution point (CP) as an exchange value among the participants. Advertisers and publishers can get CP by helping the others in the system to promote their advertisements, increasing their CP by one unit. Similarly, advertisers and publishers can use their CP to ask for assistance from the others, decreasing their CP by one unit. The result shows that the system in a Wi-Fi union is easy to use, and advertisements can be seen by all customers who are using free Wi-Fi from the stores of the union. This method can solve the problem of cost and fixed consumer groups. Full article

(This article belongs to the Special Issue Selected Papers from IEEE ICASI 2017)

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Open AccessArticle The Regular Interaction Pattern among Odorants of the Same Type and Its Application in Odor Intensity Assessment

by Luchun Yan, Jiemin Liu, Shen Jiang, Chuandong Wu and Kewei Gao

Sensors 2017, 17(7), 1624; doi:10.3390/s17071624

Received: 12 June 2017 / Revised: 8 July 2017 / Accepted: 11 July 2017 / Published: 13 July 2017

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Abstract

The olfactory evaluation function (e.g., odor intensity rating) of e-nose is always one of the most challenging issues in researches about odor pollution monitoring. But odor is normally produced by a set of stimuli, and odor interactions among constituents significantly influenced their mixture’s

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The olfactory evaluation function (e.g., odor intensity rating) of e-nose is always one of the most challenging issues in researches about odor pollution monitoring. But odor is normally produced by a set of stimuli, and odor interactions among constituents significantly influenced their mixture’s odor intensity. This study investigated the odor interaction principle in odor mixtures of aldehydes and esters, respectively. Then, a modified vector model (MVM) was proposed and it successfully demonstrated the similarity of the odor interaction pattern among odorants of the same type. Based on the regular interaction pattern, unlike a determined empirical model only fit for a specific odor mixture in conventional approaches, the MVM distinctly simplified the odor intensity prediction of odor mixtures. Furthermore, the MVM also provided a way of directly converting constituents’ chemical concentrations to their mixture’s odor intensity. By combining the MVM with usual data-processing algorithm of e-nose, a new e-nose system was established for an odor intensity rating. Compared with instrumental analysis and human assessor, it exhibited accuracy well in both quantitative analysis (Pearson correlation coefficient was 0.999 for individual aldehydes (n = 12), 0.996 for their binary mixtures (n = 36) and 0.990 for their ternary mixtures (n = 60)) and odor intensity assessment (Pearson correlation coefficient was 0.980 for individual aldehydes (n = 15), 0.973 for their binary mixtures (n = 24), and 0.888 for their ternary mixtures (n = 25)). Thus, the observed regular interaction pattern is considered an important foundation for accelerating extensive application of olfactory evaluation in odor pollution monitoring. Full article

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

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Open AccessArticle Effect of Distributed Mass on the Node, Frequency, and Sensitivity of Resonant-Mode Based Cantilevers

by Kewei Zhang, Qianke Zhu and Zhe Chen

Sensors 2017, 17(7), 1621; doi:10.3390/s17071621

Received: 8 June 2017 / Revised: 1 July 2017 / Accepted: 5 July 2017 / Published: 13 July 2017

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Abstract

We derived an analytical expression for a resonant-mode based bi-layered cantilever with distributed mass load. The behavior of mode of vibration, nodal position, frequency shift, as well as sensitivity under different mass load distributions was theoretically studied. The theoretical results suggested that asymmetric

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We derived an analytical expression for a resonant-mode based bi-layered cantilever with distributed mass load. The behavior of mode of vibration, nodal position, frequency shift, as well as sensitivity under different mass load distributions was theoretically studied. The theoretical results suggested that asymmetric mass load distribution leads to the shift of nodes as well as the sensitive regions of a resonant-mode based cantilever. n − 1 local maximal sensitivities and n − 1 local minimal sensitivities are observed when the cantilever vibrates in the nth-order resonance. The maximal sensitivity is found at the first local maximal sensitivity and the behavior of mass load length as a function of the maximal sensitivity follows the rule of an exponent decaying function. The sensitivity increases as the load mass increases for the same mass load distribution, but the corresponding slopes are different. Full article

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

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Open AccessReview The Application of Whole Cell-Based Biosensors for Use in Environmental Analysis and in Medical Diagnostics

by Qingyuan Gui, Tom Lawson, Suyan Shan, Lu Yan and Yong Liu

Sensors 2017, 17(7), 1623; doi:10.3390/s17071623

Received: 11 May 2017 / Revised: 7 July 2017 / Accepted: 8 July 2017 / Published: 13 July 2017

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Abstract

Various whole cell-based biosensors have been reported in the literature for the last 20 years and these reports have shown great potential for their use in the areas of pollution detection in environmental and in biomedical diagnostics. Unlike other reviews of this growing

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Various whole cell-based biosensors have been reported in the literature for the last 20 years and these reports have shown great potential for their use in the areas of pollution detection in environmental and in biomedical diagnostics. Unlike other reviews of this growing field, this mini-review argues that: (1) the selection of reporter genes and their regulatory proteins are directly linked to the performance of celllular biosensors; (2) broad enhancements in microelectronics and information technologies have also led to improvements in the performance of these sensors; (3) their future potential is most apparent in their use in the areas of medical diagnostics and in environmental monitoring; and (4) currently the most promising work is focused on the better integration of cellular sensors with nano and micro scaled integrated chips. With better integration it may become practical to see these cells used as (5) real-time portable devices for diagnostics at the bedside and for remote environmental toxin detection and this in situ application will make the technology commonplace and thus as unremarkable as other ubiquitous technologies. Full article

(This article belongs to the Special Issue Whole Cell-Based Biosensors and Application)

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Open AccessReview Novel Flexible Wearable Sensor Materials and Signal Processing for Vital Sign and Human Activity Monitoring

by Amir Servati, Liang Zou, Z. Jane Wang, Frank Ko and Peyman Servati

Sensors 2017, 17(7), 1622; doi:10.3390/s17071622

Received: 31 March 2017 / Revised: 25 May 2017 / Accepted: 21 June 2017 / Published: 13 July 2017

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Abstract

Advances in flexible electronic materials and smart textile, along with broad availability of smart phones, cloud and wireless systems have empowered the wearable technologies for significant impact on future of digital and personalized healthcare as well as consumer electronics. However, challenges related to

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Advances in flexible electronic materials and smart textile, along with broad availability of smart phones, cloud and wireless systems have empowered the wearable technologies for significant impact on future of digital and personalized healthcare as well as consumer electronics. However, challenges related to lack of accuracy, reliability, high power consumption, rigid or bulky form factor and difficulty in interpretation of data have limited their wide-scale application in these potential areas. As an important solution to these challenges, we present latest advances in novel flexible electronic materials and sensors that enable comfortable and conformable body interaction and potential for invisible integration within daily apparel. Advances in novel flexible materials and sensors are described for wearable monitoring of human vital signs including, body temperature, respiratory rate and heart rate, muscle movements and activity. We then present advances in signal processing focusing on motion and noise artifact removal, data mining and aspects of sensor fusion relevant to future clinical applications of wearable technology. Full article

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

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Open AccessArticle Challenges in Wireless System Integration as Enablers for Indoor Context Aware Environments

by Peio López-Iturri, Erik Aguirre, Leyre Azpilicueta, José Javier Astrain, Jesús Villandangos and Francisco Falcone

Sensors 2017, 17(7), 1616; doi:10.3390/s17071616

Received: 31 May 2017 / Revised: 8 July 2017 / Accepted: 10 July 2017 / Published: 12 July 2017

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Abstract

The advent of fully interactive environments within Smart Cities and Smart Regions requires the use of multiple wireless systems. In the case of user-device interaction, which finds multiple applications such as Ambient Assisted Living, Intelligent Transportation Systems or Smart Grids, among others, large

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The advent of fully interactive environments within Smart Cities and Smart Regions requires the use of multiple wireless systems. In the case of user-device interaction, which finds multiple applications such as Ambient Assisted Living, Intelligent Transportation Systems or Smart Grids, among others, large amount of transceivers are employed in order to achieve anytime, anyplace and any device connectivity. The resulting combination of heterogeneous wireless network exhibits fundamental limitations derived from Coverage/Capacity relations, as a function of required Quality of Service parameters, required bit rate, energy restrictions and adaptive modulation and coding schemes. In this context, inherent transceiver density poses challenges in overall system operation, given by multiple node operation which increases overall interference levels. In this work, a deterministic based analysis applied to variable density wireless sensor network operation within complex indoor scenarios is presented, as a function of topological node distribution. The extensive analysis derives interference characterizations, both for conventional transceivers as well as wearables, which provide relevant information in terms of individual node configuration as well as complete network layout. Full article

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

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Open AccessArticle Fabrication of Flexible Arrayed Lactate Biosensor Based on Immobilizing LDH-NAD⁺ on NiO Film Modified by GO and MBs

by Jung-Chuan Chou, Siao-Jie Yan, Yi-Hung Liao, Chih-Hsien Lai, You-Xiang Wu, Cian-Yi Wu, Hsiang-Yi Chen, Hong-Yu Huang and Tong-Yu Wu

Sensors 2017, 17(7), 1618; doi:10.3390/s17071618

Received: 30 May 2017 / Revised: 1 July 2017 / Accepted: 7 July 2017 / Published: 12 July 2017

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Abstract

We proposed the flexible arrayed lactate biosensor based on immobilizing l-lactate dehydrogenase (LDH) and nicotinamide adenine dinucleotide (

{NAD}^{+}

) on nickel oxide (NiO) film, and which the average sensitivity could be enhanced by using graphene oxide (GO) and magnetic beads

[...] Read more.

We proposed the flexible arrayed lactate biosensor based on immobilizing l-lactate dehydrogenase (LDH) and nicotinamide adenine dinucleotide (

{NAD}^{+}

) on nickel oxide (NiO) film, and which the average sensitivity could be enhanced by using graphene oxide (GO) and magnetic beads (MBs). By using GO and MBs, it exhibits excellent sensitivity (45.397 mV/mM) with a linearity of 0.992 in a range of 0.2 mM to 3 mM. According to the results of electrochemical impedance spectroscopy (EIS), the electron transfer resistance of LDH-

{NAD}^{+}

-MBs/GPTS/GO/NiO film was smaller than those of LDH-NAD⁺/GPTS/GO/NiO film and LDH-

{NAD}^{+}

/GPTS/NiO film, and it presented the outstanding electron transfer ability. After that, the limit of detection, anti-interference effect and bending test were also investigated. Full article

(This article belongs to the Section Biosensors)

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Open AccessArticle Cross Deployment Networking and Systematic Performance Analysis of Underwater Wireless Sensor Networks

by Zhengxian Wei, Min Song, Guisheng Yin, Hongbin Wang, Xuefei Ma and Houbing Song

Sensors 2017, 17(7), 1619; doi:10.3390/s17071619

Received: 5 May 2017 / Revised: 27 June 2017 / Accepted: 7 July 2017 / Published: 12 July 2017

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Abstract

Underwater wireless sensor networks (UWSNs) have become a new hot research area. However, due to the work dynamics and harsh ocean environment, how to obtain an UWSN with the best systematic performance while deploying as few sensor nodes as possible and setting up

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Underwater wireless sensor networks (UWSNs) have become a new hot research area. However, due to the work dynamics and harsh ocean environment, how to obtain an UWSN with the best systematic performance while deploying as few sensor nodes as possible and setting up self-adaptive networking is an urgent problem that needs to be solved. Consequently, sensor deployment, networking, and performance calculation of UWSNs are challenging issues, hence the study in this paper centers on this topic and three relevant methods and models are put forward. Firstly, the normal body-centered cubic lattice to cross body-centered cubic lattice (CBCL) has been improved, and a deployment process and topology generation method are built. Then most importantly, a cross deployment networking method (CDNM) for UWSNs suitable for the underwater environment is proposed. Furthermore, a systematic quar-performance calculation model (SQPCM) is proposed from an integrated perspective, in which the systematic performance of a UWSN includes coverage, connectivity, durability and rapid-reactivity. Besides, measurement models are established based on the relationship between systematic performance and influencing parameters. Finally, the influencing parameters are divided into three types, namely, constraint parameters, device performance and networking parameters. Based on these, a networking parameters adjustment method (NPAM) for optimized systematic performance of UWSNs has been presented. The simulation results demonstrate that the approach proposed in this paper is feasible and efficient in networking and performance calculation of UWSNs. Full article

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

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Open AccessArticle Sea Ice Detection Based on Differential Delay-Doppler Maps from UK TechDemoSat-1

by Yongchao Zhu, Kegen Yu, Jingui Zou and Jens Wickert

Sensors 2017, 17(7), 1614; doi:10.3390/s17071614

Received: 21 June 2017 / Revised: 8 July 2017 / Accepted: 10 July 2017 / Published: 12 July 2017

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Abstract

Global Navigation Satellite System (GNSS) signals can be exploited to remotely sense atmosphere and land and ocean surface to retrieve a range of geophysical parameters. This paper proposes two new methods, termed as power-summation of differential Delay-Doppler Maps (PS-D) and pixel-number of differential

[...] Read more.

Global Navigation Satellite System (GNSS) signals can be exploited to remotely sense atmosphere and land and ocean surface to retrieve a range of geophysical parameters. This paper proposes two new methods, termed as power-summation of differential Delay-Doppler Maps (PS-D) and pixel-number of differential Delay-Doppler Maps (PN-D), to distinguish between sea ice and sea water using differential Delay-Doppler Maps (dDDMs). PS-D and PN-D make use of power-summation and pixel-number of dDDMs, respectively, to measure the degree of difference between two DDMs so as to determine the transition state (water-water, water-ice, ice-ice and ice-water) and hence ice and water are detected. Moreover, an adaptive incoherent averaging of DDMs is employed to improve the computational efficiency. A large number of DDMs recorded by UK TechDemoSat-1 (TDS-1) over the Arctic region are used to test the proposed sea ice detection methods. Through evaluating against ground-truth measurements from the Ocean Sea Ice SAF, the proposed PS-D and PN-D methods achieve a probability of detection of 99.72% and 99.69% respectively, while the probability of false detection is 0.28% and 0.31% respectively. Full article

(This article belongs to the Special Issue Recent Innovative Microwave Remote Sensing Instrumentation for Land Surface Applications)

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Open AccessArticle A Study on the Data Compression Technology-Based Intelligent Data Acquisition (IDAQ) System for Structural Health Monitoring of Civil Structures

by Gwanghee Heo and Joonryong Jeon

Sensors 2017, 17(7), 1620; doi:10.3390/s17071620

Received: 1 June 2017 / Revised: 10 July 2017 / Accepted: 10 July 2017 / Published: 12 July 2017

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Abstract

In this paper, a data compression technology-based intelligent data acquisition (IDAQ) system was developed for structural health monitoring of civil structures, and its validity was tested using random signals (El-Centro seismic waveform). The IDAQ system was structured to include a high-performance CPU with

[...] Read more.

In this paper, a data compression technology-based intelligent data acquisition (IDAQ) system was developed for structural health monitoring of civil structures, and its validity was tested using random signals (El-Centro seismic waveform). The IDAQ system was structured to include a high-performance CPU with large dynamic memory for multi-input and output in a radio frequency (RF) manner. In addition, the embedded software technology (EST) has been applied to it to implement diverse logics needed in the process of acquiring, processing and transmitting data. In order to utilize IDAQ system for the structural health monitoring of civil structures, this study developed an artificial filter bank by which structural dynamic responses (acceleration) were efficiently acquired, and also optimized it on the random El-Centro seismic waveform. All techniques developed in this study have been embedded to our system. The data compression technology-based IDAQ system was proven valid in acquiring valid signals in a compressed size. Full article

(This article belongs to the Special Issue Sensors and Sensor Networks for Structural Health Monitoring)

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Open AccessArticle Radio-Frequency-Based NH₃-Selective Catalytic Reduction Catalyst Control: Studies on Temperature Dependency and Humidity Influences

by Markus Dietrich, Gunter Hagen, Willibald Reitmeier, Katharina Burger, Markus Hien, Philippe Grass, David Kubinski, Jaco Visser and Ralf Moos

Sensors 2017, 17(7), 1615; doi:10.3390/s17071615

Received: 21 May 2017 / Revised: 23 June 2017 / Accepted: 28 June 2017 / Published: 12 July 2017

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Abstract

The upcoming more stringent automotive emission legislations and current developments have promoted new technologies for more precise and reliable catalyst control. For this purpose, radio-frequency-based (RF) catalyst state determination offers the only approach for directly measuring the NH₃ loading on selective catalytic

[...] Read more.

The upcoming more stringent automotive emission legislations and current developments have promoted new technologies for more precise and reliable catalyst control. For this purpose, radio-frequency-based (RF) catalyst state determination offers the only approach for directly measuring the NH₃ loading on selective catalytic reduction (SCR) catalysts and the state of other catalysts and filter systems. Recently, the ability of this technique to directly control the urea dosing on a current NH₃ storing zeolite catalyst has been demonstrated on an engine dynamometer for the first time and this paper continues that work. Therefore, a well-known serial-type and zeolite-based SCR catalyst (Cu-SSZ-13) was investigated under deliberately chosen high space velocities. At first, the full functionality of the RF system with Cu-SSZ-13 as sample was tested successfully. By direct RF-based NH₃ storage control, the influence of the storage degree on the catalyst performance, i.e., on NO_x conversion and NH₃ slip, was investigated in a temperature range between 250 and 400 °C. For each operation point, an ideal and a critical NH₃ storage degree was found and analyzed in the whole temperature range. Based on the data of all experimental runs, temperature dependent calibration functions were developed as a basis for upcoming tests under transient conditions. Additionally, the influence of exhaust humidity was observed with special focus on cold start water and its effects to the RF signals. Full article

(This article belongs to the Section Chemical Sensors)

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Open AccessArticle A Synergy Cropland of China by Fusing Multiple Existing Maps and Statistics

by Miao Lu, Wenbin Wu, Liangzhi You, Di Chen, Li Zhang, Peng Yang and Huajun Tang

Sensors 2017, 17(7), 1613; doi:10.3390/s17071613

Received: 10 May 2017 / Revised: 24 June 2017 / Accepted: 3 July 2017 / Published: 12 July 2017

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Abstract

Accurate information on cropland extent is critical for scientific research and resource management. Several cropland products from remotely sensed datasets are available. Nevertheless, significant inconsistency exists among these products and the cropland areas estimated from these products differ considerably from statistics. In this

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Accurate information on cropland extent is critical for scientific research and resource management. Several cropland products from remotely sensed datasets are available. Nevertheless, significant inconsistency exists among these products and the cropland areas estimated from these products differ considerably from statistics. In this study, we propose a hierarchical optimization synergy approach (HOSA) to develop a hybrid cropland map of China, circa 2010, by fusing five existing cropland products, i.e., GlobeLand30, Climate Change Initiative Land Cover (CCI-LC), GlobCover 2009, MODIS Collection 5 (MODIS C5), and MODIS Cropland, and sub-national statistics of cropland area. HOSA simplifies the widely used method of score assignment into two steps, including determination of optimal agreement level and identification of the best product combination. The accuracy assessment indicates that the synergy map has higher accuracy of spatial locations and better consistency with statistics than the five existing datasets individually. This suggests that the synergy approach can improve the accuracy of cropland mapping and enhance consistency with statistics. Full article

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

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Open AccessArticle A Fine-Grained and Privacy-Preserving Query Scheme for Fog Computing-Enhanced Location-Based Service

by Xue Yang, Fan Yin and Xiaohu Tang

Sensors 2017, 17(7), 1611; doi:10.3390/s17071611

Received: 31 May 2017 / Revised: 29 June 2017 / Accepted: 7 July 2017 / Published: 11 July 2017

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Abstract

Location-based services (LBS), as one of the most popular location-awareness applications, has been further developed to achieve low-latency with the assistance of fog computing. However, privacy issues remain a research challenge in the context of fog computing. Therefore, in this paper, we present

[...] Read more.

Location-based services (LBS), as one of the most popular location-awareness applications, has been further developed to achieve low-latency with the assistance of fog computing. However, privacy issues remain a research challenge in the context of fog computing. Therefore, in this paper, we present a fine-grained and privacy-preserving query scheme for fog computing-enhanced location-based services, hereafter referred to as FGPQ. In particular, mobile users can obtain the fine-grained searching result satisfying not only the given spatial range but also the searching content. Detailed privacy analysis shows that our proposed scheme indeed achieves the privacy preservation for the LBS provider and mobile users. In addition, extensive performance analyses and experiments demonstrate that the FGPQ scheme can significantly reduce computational and communication overheads and ensure the low-latency, which outperforms existing state-of-the art schemes. Hence, our proposed scheme is more suitable for real-time LBS searching. Full article

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

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Open AccessArticle Secure Service Proxy: A CoAP(s) Intermediary for a Securer and Smarter Web of Things

by Floris Van den Abeele, Ingrid Moerman, Piet Demeester and Jeroen Hoebeke

Sensors 2017, 17(7), 1609; doi:10.3390/s17071609

Received: 21 May 2017 / Revised: 30 June 2017 / Accepted: 6 July 2017 / Published: 11 July 2017

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Abstract

As the IoT continues to grow over the coming years, resource-constrained devices and networks will see an increase in traffic as everything is connected in an open Web of Things. The performance- and function-enhancing features are difficult to provide in resource-constrained environments, but

[...] Read more.

As the IoT continues to grow over the coming years, resource-constrained devices and networks will see an increase in traffic as everything is connected in an open Web of Things. The performance- and function-enhancing features are difficult to provide in resource-constrained environments, but will gain importance if the WoT is to be scaled up successfully. For example, scalable open standards-based authentication and authorization will be important to manage access to the limited resources of constrained devices and networks. Additionally, features such as caching and virtualization may help further reduce the load on these constrained systems. This work presents the Secure Service Proxy (SSP): a constrained-network edge proxy with the goal of improving the performance and functionality of constrained RESTful environments. Our evaluations show that the proposed design reaches its goal by reducing the load on constrained devices while implementing a wide range of features as different adapters. Specifically, the results show that the SSP leads to significant savings in processing, network traffic, network delay and packet loss rates for constrained devices. As a result, the SSP helps to guarantee the proper operation of constrained networks as these networks form an ever-expanding Web of Things. Full article

(This article belongs to the Section Sensor Networks)

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Open AccessArticle Secure and Time-Aware Communication of Wireless Sensors Monitoring Overhead Transmission Lines

by Katarzyna Mazur, Michal Wydra and Bogdan Ksiezopolski

Sensors 2017, 17(7), 1610; doi:10.3390/s17071610

Received: 17 May 2017 / Revised: 30 June 2017 / Accepted: 4 July 2017 / Published: 11 July 2017

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Abstract

Existing transmission power grids suffer from high maintenance costs and scalability issues along with a lack of effective and secure system monitoring. To address these problems, we propose to use Wireless Sensor Networks (WSNs) as a technology to achieve energy efficient, reliable, and

[...] Read more.

Existing transmission power grids suffer from high maintenance costs and scalability issues along with a lack of effective and secure system monitoring. To address these problems, we propose to use Wireless Sensor Networks (WSNs) as a technology to achieve energy efficient, reliable, and low-cost remote monitoring of transmission grids. With WSNs, smart grid enables both utilities and customers to monitor, predict and manage energy usage effectively and react to possible power grid disturbances in a timely manner. However, the increased application of WSNs also introduces new security challenges, especially related to privacy, connectivity, and security management, repeatedly causing unpredicted expenditures. Monitoring the status of the power system, a large amount of sensors generates massive amount of sensitive data. In order to build an effective Wireless Sensor Network (WSN) for a smart grid, we focus on designing a methodology of efficient and secure delivery of the data measured on transmission lines. We perform a set of simulations, in which we examine different routing algorithms, security mechanisms and WSN deployments in order to select the parameters that will not affect the delivery time but fulfill their role and ensure security at the same time. Furthermore, we analyze the optimal placement of direct wireless links, aiming at minimizing time delays, balancing network performance and decreasing deployment costs. Full article

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

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Open AccessArticle Rapid ELISA Using a Film-Stack Reaction Field with Micropillar Arrays

by Yuma Suzuki, Kazuhiro Morioka, Soichiro Ohata, Tetsuhide Shimizu, Hizuru Nakajima, Katsumi Uchiyama and Ming Yang

Sensors 2017, 17(7), 1608; doi:10.3390/s17071608

Received: 20 May 2017 / Revised: 26 June 2017 / Accepted: 9 July 2017 / Published: 11 July 2017

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Abstract

A film-stack reaction field with a micropillar array using a motor stirrer was developed for the high sensitivity and rapid enzyme-linked immunosorbent assay (ELISA) reaction. The effects of the incubation time of a protein (30 s, 5 min, and 10 min) on the

[...] Read more.

A film-stack reaction field with a micropillar array using a motor stirrer was developed for the high sensitivity and rapid enzyme-linked immunosorbent assay (ELISA) reaction. The effects of the incubation time of a protein (30 s, 5 min, and 10 min) on the fluorescence intensity in ELISAs were investigated using a reaction field with different micropillar array dimensions (5-µm, 10-µm and 50-µm gaps between the micropillars). The difference in fluorescence intensity between the well with the reaction field of 50-µm gap for the incubation time of 30 s and the well without the reaction field with for incubation time of 10 min was 6%. The trend of the fluorescence intensity in the gap between the micro pillars in the film-stack reaction field was different between the short incubation time and the long incubation time. The theoretical analysis of the physical parameters related with the biomolecule transport indicated that the reaction efficiency defined in this study was the dominant factor determining the fluorescence intensity for the short incubation time, whereas the volumetric rate of the circulating flow through the space between films and the specific surface area were the dominant factors for the long incubation time. Full article

(This article belongs to the Section Biosensors)

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Open AccessArticle Task Assignment and Path Planning for Multiple Autonomous Underwater Vehicles Using 3D Dubins Curves ^†

by Wenyu Cai, Meiyan Zhang and Yahong Rosa Zheng

Sensors 2017, 17(7), 1607; doi:10.3390/s17071607

Received: 1 March 2017 / Revised: 22 June 2017 / Accepted: 6 July 2017 / Published: 11 July 2017

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Abstract

This paper investigates the task assignment and path planning problem for multiple AUVs in three dimensional (3D) underwater wireless sensor networks where nonholonomic motion constraints of underwater AUVs in 3D space are considered. The multi-target task assignment and path planning problem is modeled

[...] Read more.

This paper investigates the task assignment and path planning problem for multiple AUVs in three dimensional (3D) underwater wireless sensor networks where nonholonomic motion constraints of underwater AUVs in 3D space are considered. The multi-target task assignment and path planning problem is modeled by the Multiple Traveling Sales Person (MTSP) problem and the Genetic Algorithm (GA) is used to solve the MTSP problem with Euclidean distance as the cost function and the Tour Hop Balance (THB) or Tour Length Balance (TLB) constraints as the stop criterion. The resulting tour sequences are mapped to 2D Dubins curves in the

X - Y

plane, and then interpolated linearly to obtain the Z coordinates. We demonstrate that the linear interpolation fails to achieve

G^{1}

continuity in the 3D Dubins path for multiple targets. Therefore, the interpolated 3D Dubins curves are checked against the AUV dynamics constraint and the ones satisfying the constraint are accepted to finalize the 3D Dubins curve selection. Simulation results demonstrate that the integration of the 3D Dubins curve with the MTSP model is successful and effective for solving the 3D target assignment and path planning problem. Full article

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

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Open AccessCommunication Candle Soot Coating for Latent Fingermark Enhancement on Various Surfaces

by Qianhui Wei, Yu Zhu, Shouliang Liu, Yongjie Gao, Xiaolong Li, Mi Shi, Xueji Zhang and Meiqin Zhang

Sensors 2017, 17(7), 1612; doi:10.3390/s17071612

Received: 10 May 2017 / Revised: 12 June 2017 / Accepted: 3 July 2017 / Published: 11 July 2017

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Abstract

We demonstrate a facile method termed candle soot coating (CSC) for fast developing latent fingermarks (LFMs) on various kinds of surfaces (glass, ceramic, metal, paper and adhesive tape). The CSC method can be considered as simple, fast, and low-cost as well as providing

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We demonstrate a facile method termed candle soot coating (CSC) for fast developing latent fingermarks (LFMs) on various kinds of surfaces (glass, ceramic, metal, paper and adhesive tape). The CSC method can be considered as simple, fast, and low-cost as well as providing high contrast for LFM visualization in potential forensic applications. Full article

(This article belongs to the Section Chemical Sensors)

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Open AccessReview Traceability of On-Machine Tool Measurement: A Review

by Unai Mutilba, Eneko Gomez-Acedo, Gorka Kortaberria, Aitor Olarra and Jose A. Yagüe-Fabra

Sensors 2017, 17(7), 1605; doi:10.3390/s17071605

Received: 1 May 2017 / Revised: 24 June 2017 / Accepted: 27 June 2017 / Published: 11 July 2017

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Abstract

Nowadays, errors during the manufacturing process of high value components are not acceptable in driving industries such as energy and transportation. Sectors such as aerospace, automotive, shipbuilding, nuclear power, large science facilities or wind power need complex and accurate components that demand close

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Nowadays, errors during the manufacturing process of high value components are not acceptable in driving industries such as energy and transportation. Sectors such as aerospace, automotive, shipbuilding, nuclear power, large science facilities or wind power need complex and accurate components that demand close measurements and fast feedback into their manufacturing processes. New measuring technologies are already available in machine tools, including integrated touch probes and fast interface capabilities. They provide the possibility to measure the workpiece in-machine during or after its manufacture, maintaining the original setup of the workpiece and avoiding the manufacturing process from being interrupted to transport the workpiece to a measuring position. However, the traceability of the measurement process on a machine tool is not ensured yet and measurement data is still not fully reliable enough for process control or product validation. The scientific objective is to determine the uncertainty on a machine tool measurement and, therefore, convert it into a machine integrated traceable measuring process. For that purpose, an error budget should consider error sources such as the machine tools, components under measurement and the interactions between both of them. This paper reviews all those uncertainty sources, being mainly focused on those related to the machine tool, either on the process of geometric error assessment of the machine or on the technology employed to probe the measurand. Full article

(This article belongs to the Section Physical Sensors)

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Open AccessArticle Array of Chemosensitive Resistors with Composites of Gas Chromatography (GC) Materials and Carbon Black for Detection and Recognition of VOCs: A Basic Study

by Bartosz Wyszynski, Rui Yatabe, Atsuo Nakao, Masaya Nakatani, Akio Oki, Hiroaki Oka and Kiyoshi Toko

Sensors 2017, 17(7), 1606; doi:10.3390/s17071606

Received: 21 April 2017 / Revised: 29 June 2017 / Accepted: 5 July 2017 / Published: 11 July 2017

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Abstract

Mimicking the biological olfaction, large odor-sensor arrays can be used to acquire a broad range of chemical information, with a potentially high degree of redundancy, to allow for enhanced control over the sensitivity and selectivity of artificial olfaction systems. The arrays should consist

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Mimicking the biological olfaction, large odor-sensor arrays can be used to acquire a broad range of chemical information, with a potentially high degree of redundancy, to allow for enhanced control over the sensitivity and selectivity of artificial olfaction systems. The arrays should consist of the largest possible number of individual sensing elements while being miniaturized. Chemosensitive resistors are one of the sensing platforms that have a potential to satisfy these two conditions. In this work we test viability of fabricating a 16-element chemosensitive resistor array for detection and recognition of volatile organic compounds (VOCs). The sensors were fabricated using blends of carbon black and gas chromatography (GC) stationary-phase materials preselected based on their sorption properties. Blends of the selected GC materials with carbon black particles were subsequently coated over chemosensitive resistor devices and the resulting sensors/arrays evaluated in exposure experiments against vapors of pyrrole, benzenal, nonanal, and 2-phenethylamine at 150, 300, 450, and 900 ppb. Responses of the fabricated 16-element array were stable and differed for each individual odorant sample, proving the blends of GC materials with carbon black particles can be effectively used for fabrication of large odor-sensing arrays based on chemosensitive resistors. The obtained results suggest that the proposed sensing devices could be effective in discriminating odor/vapor samples at the sub-ppm level. Full article

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

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Open AccessArticle A Smartphone-Based Automatic Measurement Method for Colorimetric pH Detection Using a Color Adaptation Algorithm

by Sung Deuk Kim, Youngmi Koo and Yeoheung Yun

Sensors 2017, 17(7), 1604; doi:10.3390/s17071604

Received: 5 June 2017 / Revised: 26 June 2017 / Accepted: 7 July 2017 / Published: 10 July 2017

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Abstract

This paper proposes a smartphone-based colorimetric pH detection method using a color adaptation algorithm for point-of-care applications. Although a smartphone camera can be utilized to measure the color information of colorimetric sensors, ambient light changes and unknown built-in automatic image correction operations make

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This paper proposes a smartphone-based colorimetric pH detection method using a color adaptation algorithm for point-of-care applications. Although a smartphone camera can be utilized to measure the color information of colorimetric sensors, ambient light changes and unknown built-in automatic image correction operations make it difficult to obtain stable color information. This paper utilizes a 3D printed mini light box and performs a calibration procedure with a paper-printed comparison chart and a reference image which overcomes the drawbacks of smartphone cameras and the difficulty in preparing for the calibration procedure. The color adaptation is performed in the CIE 1976 u’v’ color space by using the reference paper in order to stabilize the color variations. Non-rigid u’v’ curve interpolation is used to produce the high-resolution pH estimate. The final pH value is estimated by using the best-matching method to handle the nonlinear curve properties of multiple color patches. The experimental results obtained using a pH indicator paper show that the proposed algorithm provides reasonably good estimation of pH detection. With paper-printed accurate color comparison charts and smart color adaptation techniques, superior estimation is achieved in the smartphone-based colorimetric pH detection system for point-of-care application. Full article

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

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Open AccessArticle Microfluidic Platform for the Long-Term On-Chip Cultivation of Mammalian Cells for Lab-On-A-Chip Applications

by Frank Bunge, Sander van den Driesche and Michael J. Vellekoop

Sensors 2017, 17(7), 1603; doi:10.3390/s17071603

Received: 30 May 2017 / Revised: 4 July 2017 / Accepted: 4 July 2017 / Published: 10 July 2017

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Abstract

Lab-on-a-Chip (LoC) applications for the long-term analysis of mammalian cells are still very rare due to the lack of convenient cell cultivation devices. The difficulties are the integration of suitable supply structures, the need of expensive equipment like an incubator and sophisticated pumps

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Lab-on-a-Chip (LoC) applications for the long-term analysis of mammalian cells are still very rare due to the lack of convenient cell cultivation devices. The difficulties are the integration of suitable supply structures, the need of expensive equipment like an incubator and sophisticated pumps as well as the choice of material. The presented device is made out of hard, but non-cytotoxic materials (silicon and glass) and contains two vertical arranged membranes out of hydrogel. The porous membranes are used to separate the culture chamber from two supply channels for gases and nutrients. The cells are fed continuously by diffusion through the membranes without the need of an incubator and low requirements on the supply of medium to the assembly. The diffusion of oxygen is modelled in order to find the optimal dimensions of the chamber. The chip is connected via 3D-printed holders to the macroscopic world. The holders are coated with Parlyene C to ensure that only biocompatible materials are in contact with the culture medium. The experiments with MDCK-cells show the successful seeding inside the chip, culturing and passaging. Consequently, the presented platform is a step towards Lab-on-a-Chip applications that require long-term cultivation of mammalian cells. Full article

(This article belongs to the Special Issue Whole Cell-Based Biosensors and Application)

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Open AccessArticle Rapid Surface Enhanced Raman Scattering (SERS) Detection of Sibutramine Hydrochloride in Pharmaceutical Capsules with a β-Cyclodextrin- Ag/Polyvivnyl Alcohol Hydrogel Substrate

by Lei Ouyang, Zuyan Jiang, Nan Wang, Lihua Zhu and Heqing Tang

Sensors 2017, 17(7), 1601; doi:10.3390/s17071601

Received: 21 May 2017 / Revised: 17 June 2017 / Accepted: 20 June 2017 / Published: 10 July 2017

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Abstract

Sibutramine hydrochloride (SH) is a banned weight-loss drug, but its illegal addition to health products is still rampant. This suggests a very urgent need for a fast and precise detection method for SH. Surface Enhanced Raman Scattering (SERS) is a promising candidate for

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Sibutramine hydrochloride (SH) is a banned weight-loss drug, but its illegal addition to health products is still rampant. This suggests a very urgent need for a fast and precise detection method for SH. Surface Enhanced Raman Scattering (SERS) is a promising candidate for this purpose, but the weak affinity between SH and bare metal limits its direct SERS detection. In the present work, β-cyclodextrin was capped in situ onto the surface of Ag nanoparticles to function as a scaffold to capture SH. The obtained Ag nanoparticles were encapsulated into polyvinyl alcohol (PVA) to fabricate a SERS active hydrogel with excellent reproducibility. A facile SERS strategy based on such substrate was proposed for trace SH quantification with a linear range of 7.0–150.0 µg·mL^–1, and a detection limit low to 3.0 µg·mL⁻¹. It was applied to analyze seven types of commercial slimming capsules with satisfactory results, showing good prospect for real applications. Full article

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

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Open AccessArticle Energy Harvesting Based Body Area Networks for Smart Health

by Yixue Hao, Limei Peng, Huimin Lu, Mohammad Mehedi Hassan and Atif Alamri

Sensors 2017, 17(7), 1602; doi:10.3390/s17071602

Received: 7 May 2017 / Revised: 29 June 2017 / Accepted: 1 July 2017 / Published: 10 July 2017

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Abstract

Body area networks (BANs) are configured with a great number of ultra-low power consumption wearable devices, which constantly monitor physiological signals of the human body and thus realize intelligent monitoring. However, the collection and transfer of human body signals consume energy, and considering

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Body area networks (BANs) are configured with a great number of ultra-low power consumption wearable devices, which constantly monitor physiological signals of the human body and thus realize intelligent monitoring. However, the collection and transfer of human body signals consume energy, and considering the comfort demand of wearable devices, both the size and the capacity of a wearable device’s battery are limited. Thus, minimizing the energy consumption of wearable devices and optimizing the BAN energy efficiency is still a challenging problem. Therefore, in this paper, we propose an energy harvesting-based BAN for smart health and discuss an optimal resource allocation scheme to improve BAN energy efficiency. Specifically, firstly, considering energy harvesting in a BAN and the time limits of human body signal transfer, we formulate the energy efficiency optimization problem of time division for wireless energy transfer and wireless information transfer. Secondly, we convert the optimization problem into a convex optimization problem under a linear constraint and propose a closed-form solution to the problem. Finally, simulation results proved that when the size of data acquired by the wearable devices is small, the proportion of energy consumed by the circuit and signal acquisition of the wearable devices is big, and when the size of data acquired by the wearable devices is big, the energy consumed by the signal transfer of the wearable device is decisive. Full article

(This article belongs to the Special Issue Sensor Intelligence Assisted by Data Analytics and Cognitive Computing)

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Open AccessArticle Polar Grid Navigation Algorithm for Unmanned Underwater Vehicles

by Zheping Yan, Lu Wang, Wei Zhang, Jiajia Zhou and Man Wang

Sensors 2017, 17(7), 1599; doi:10.3390/s17071599

Received: 25 May 2017 / Revised: 26 June 2017 / Accepted: 6 July 2017 / Published: 9 July 2017

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Abstract

To solve the unavailability of a traditional strapdown inertial navigation system (SINS) for unmanned underwater vehicles (UUVs) in the polar region, a polar grid navigation algorithm for UUVs is proposed in this paper. Precise navigation is the basis for UUVs to complete missions.

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To solve the unavailability of a traditional strapdown inertial navigation system (SINS) for unmanned underwater vehicles (UUVs) in the polar region, a polar grid navigation algorithm for UUVs is proposed in this paper. Precise navigation is the basis for UUVs to complete missions. The rapid convergence of Earth meridians and the serious polar environment make it difficult to establish the true heading of the UUV at a particular instant. Traditional SINS and traditional representation of position are not suitable in the polar region. Due to the restrictions of the complex underwater conditions in the polar region, a SINS based on the grid frame with the assistance of the OCTANS and the Doppler velocity log (DVL) is chosen for a UUV navigating in the polar region. Data fusion of the integrated navigation system is realized by a modified fuzzy adaptive Kalman filter (MFAKF). By neglecting the negative terms, and using T-S fuzzy logic in the adaptive regulation of the noise covariance, the proposed filter algorithm can improve navigation accuracy. Simulation and experimental results demonstrate that the polar grid navigation algorithm can effectively navigate a UUV sailing in the polar region. Full article

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

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Open AccessArticle Hardware/Software Data Acquisition System for Real Time Cell Temperature Monitoring in Air-Cooled Polymer Electrolyte Fuel Cells

by Francisca Segura, Veronica Bartolucci and José Manuel Andújar

Sensors 2017, 17(7), 1600; doi:10.3390/s17071600

Received: 3 May 2017 / Revised: 5 July 2017 / Accepted: 7 July 2017 / Published: 9 July 2017

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Abstract

This work presents a hardware/software data acquisition system developed for monitoring the temperature in real time of the cells in Air-Cooled Polymer Electrolyte Fuel Cells (AC-PEFC). These fuel cells are of great interest because they can carry out, in a single operation, the

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This work presents a hardware/software data acquisition system developed for monitoring the temperature in real time of the cells in Air-Cooled Polymer Electrolyte Fuel Cells (AC-PEFC). These fuel cells are of great interest because they can carry out, in a single operation, the processes of oxidation and refrigeration. This allows reduction of weight, volume, cost and complexity of the control system in the AC-PEFC. In this type of PEFC (and in general in any PEFC), the reliable monitoring of temperature along the entire surface of the stack is fundamental, since a suitable temperature and a regular distribution thereof, are key for a better performance of the stack and a longer lifetime under the best operating conditions. The developed data acquisition (DAQ) system can perform non-intrusive temperature measurements of each individual cell of an AC-PEFC stack of any power (from watts to kilowatts). The stack power is related to the temperature gradient; i.e., a higher power corresponds to a higher stack surface, and consequently higher temperature difference between the coldest and the hottest point. The developed DAQ system has been implemented with the low-cost open-source platform Arduino, and it is completed with a modular virtual instrument that has been developed using NI LabVIEW. Temperature vs time evolution of all the cells of an AC-PEFC both together and individually can be registered and supervised. The paper explains comprehensively the developed DAQ system together with experimental results that demonstrate the suitability of the system. Full article

(This article belongs to the Special Issue Biofuel Cells)

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Open AccessArticle On Transform Domain Communication Systems under Spectrum Sensing Mismatch: A Deterministic Analysis

by Chuanxue Jin, Su Hu, Yixuan Huang, Qu Luo, Dan Huang, Yi Li, Yuan Gao and Shaochi Cheng

Sensors 2017, 17(7), 1594; doi:10.3390/s17071594

Received: 2 May 2017 / Revised: 15 June 2017 / Accepted: 30 June 2017 / Published: 8 July 2017

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Abstract

Towards the era of mobile Internet and the Internet of Things (IoT), numerous sensors and devices are being introduced and interconnected. To support such an amount of data traffic, traditional wireless communication technologies are facing challenges both in terms of the increasing shortage

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Towards the era of mobile Internet and the Internet of Things (IoT), numerous sensors and devices are being introduced and interconnected. To support such an amount of data traffic, traditional wireless communication technologies are facing challenges both in terms of the increasing shortage of spectrum resources and massive multiple access. The transform-domain communication system (TDCS) is considered as an alternative multiple access system, where 5G and mobile IoT are mainly focused. However, previous studies about TDCS are under the assumption that the transceiver has the global spectrum information, without the consideration of spectrum sensing mismatch (SSM). In this paper, we present the deterministic analysis of TDCS systems under arbitrary given spectrum sensing scenarios, especially the influence of the SSM pattern to the signal to noise ratio (SNR) performance. Simulation results show that arbitrary SSM pattern can lead to inferior bit error rate (BER) performance. Full article

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

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Open AccessArticle Pedestrian Detection Based on Adaptive Selection of Visible Light or Far-Infrared Light Camera Image by Fuzzy Inference System and Convolutional Neural Network-Based Verification

by Jin Kyu Kang, Hyung Gil Hong and Kang Ryoung Park

Sensors 2017, 17(7), 1598; doi:10.3390/s17071598

Received: 16 June 2017 / Revised: 5 July 2017 / Accepted: 5 July 2017 / Published: 8 July 2017

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Abstract

A number of studies have been conducted to enhance the pedestrian detection accuracy of intelligent surveillance systems. However, detecting pedestrians under outdoor conditions is a challenging problem due to the varying lighting, shadows, and occlusions. In recent times, a growing number of studies

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A number of studies have been conducted to enhance the pedestrian detection accuracy of intelligent surveillance systems. However, detecting pedestrians under outdoor conditions is a challenging problem due to the varying lighting, shadows, and occlusions. In recent times, a growing number of studies have been performed on visible light camera-based pedestrian detection systems using a convolutional neural network (CNN) in order to make the pedestrian detection process more resilient to such conditions. However, visible light cameras still cannot detect pedestrians during nighttime, and are easily affected by shadows and lighting. There are many studies on CNN-based pedestrian detection through the use of far-infrared (FIR) light cameras (i.e., thermal cameras) to address such difficulties. However, when the solar radiation increases and the background temperature reaches the same level as the body temperature, it remains difficult for the FIR light camera to detect pedestrians due to the insignificant difference between the pedestrian and non-pedestrian features within the images. Researchers have been trying to solve this issue by inputting both the visible light and the FIR camera images into the CNN as the input. This, however, takes a longer time to process, and makes the system structure more complex as the CNN needs to process both camera images. This research adaptively selects a more appropriate candidate between two pedestrian images from visible light and FIR cameras based on a fuzzy inference system (FIS), and the selected candidate is verified with a CNN. Three types of databases were tested, taking into account various environmental factors using visible light and FIR cameras. The results showed that the proposed method performs better than the previously reported methods. Full article

(This article belongs to the Section Physical Sensors)

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Open AccessArticle A Novel Spatial Feature for the Identification of Motor Tasks Using High-Density Electromyography

by Mislav Jordanić, Mónica Rojas-Martínez, Miguel Angel Mañanas, Joan Francesc Alonso and Hamid Reza Marateb

Sensors 2017, 17(7), 1597; doi:10.3390/s17071597

Received: 21 April 2017 / Revised: 26 June 2017 / Accepted: 5 July 2017 / Published: 8 July 2017

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Abstract

Estimation of neuromuscular intention using electromyography (EMG) and pattern recognition is still an open problem. One of the reasons is that the pattern-recognition approach is greatly influenced by temporal changes in electromyograms caused by the variations in the conductivity of the skin and/or

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Estimation of neuromuscular intention using electromyography (EMG) and pattern recognition is still an open problem. One of the reasons is that the pattern-recognition approach is greatly influenced by temporal changes in electromyograms caused by the variations in the conductivity of the skin and/or electrodes, or physiological changes such as muscle fatigue. This paper proposes novel features for task identification extracted from the high-density electromyographic signal (HD-EMG) by applying the mean shift channel selection algorithm evaluated using a simple and fast classifier-linear discriminant analysis. HD-EMG was recorded from eight subjects during four upper-limb isometric motor tasks (flexion/extension, supination/pronation of the forearm) at three different levels of effort. Task and effort level identification showed very high classification rates in all cases. This new feature performed remarkably well particularly in the identification at very low effort levels. This could be a step towards the natural control in everyday applications where a subject could use low levels of effort to achieve motor tasks. Furthermore, it ensures reliable identification even in the presence of myoelectric fatigue and showed robustness to temporal changes in EMG, which could make it suitable in long-term applications. Full article

(This article belongs to the Special Issue Wearable and Ambient Sensors for Healthcare and Wellness Applications)

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Open AccessArticle Real-Time Amperometric Recording of Extracellular H₂O₂ in the Brain of Immunocompromised Mice: An In Vitro, Ex Vivo and In Vivo Characterisation Study

by Caroline H. Reid and Niall J. Finnerty

Sensors 2017, 17(7), 1596; doi:10.3390/s17071596

Received: 7 June 2017 / Revised: 3 July 2017 / Accepted: 5 July 2017 / Published: 8 July 2017

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Abstract

We detail an extensive characterisation study on a previously described dual amperometric H₂O₂ biosensor consisting of H₂O₂ detection (blank) and degradation (catalase) electrodes. In vitro investigations demonstrated excellent H₂O₂ sensitivity and selectivity against the

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We detail an extensive characterisation study on a previously described dual amperometric H₂O₂ biosensor consisting of H₂O₂ detection (blank) and degradation (catalase) electrodes. In vitro investigations demonstrated excellent H₂O₂ sensitivity and selectivity against the interferent, ascorbic acid. Ex vivo studies were performed to mimic physiological conditions prior to in vivo deployment. Exposure to brain tissue homogenate identified reliable sensitivity and selectivity recordings up to seven days for both blank and catalase electrodes. Furthermore, there was no compromise in pre- and post-implanted catalase electrode sensitivity in ex vivo mouse brain. In vivo investigations performed in anaesthetised mice confirmed the ability of the H₂O₂ biosensor to detect increases in amperometric current following locally perfused/infused H₂O₂ and antioxidant inhibitors mercaptosuccinic acid and sodium azide. Subsequent recordings in freely moving mice identified negligible effects of control saline and sodium ascorbate interference injections on amperometric H₂O₂ current. Furthermore, the stability of the amperometric current was confirmed over a five-day period and analysis of 24-h signal recordings identified the absence of diurnal variations in amperometric current. Collectively, these findings confirm the biosensor current responds in vivo to increasing exogenous and endogenous H₂O₂ and tentatively supports measurement of H₂O₂ dynamics in freely moving NOD SCID mice. Full article

(This article belongs to the Special Issue Dedication to Professor Eiichi Tamiya: Over 30 Years of Outstanding Contributions to the Field of Sensors and Biosensors)

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Open AccessArticle Multi-National Banknote Classification Based on Visible-light Line Sensor and Convolutional Neural Network

by Tuyen Danh Pham, Dong Eun Lee and Kang Ryoung Park

Sensors 2017, 17(7), 1595; doi:10.3390/s17071595

Received: 9 June 2017 / Revised: 6 July 2017 / Accepted: 6 July 2017 / Published: 8 July 2017

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Abstract

Automatic recognition of banknotes is applied in payment facilities, such as automated teller machines (ATMs) and banknote counters. Besides the popular approaches that focus on studying the methods applied to various individual types of currencies, there have been studies conducted on simultaneous classification

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Automatic recognition of banknotes is applied in payment facilities, such as automated teller machines (ATMs) and banknote counters. Besides the popular approaches that focus on studying the methods applied to various individual types of currencies, there have been studies conducted on simultaneous classification of banknotes from multiple countries. However, their methods were conducted with limited numbers of banknote images, national currencies, and denominations. To address this issue, we propose a multi-national banknote classification method based on visible-light banknote images captured by a one-dimensional line sensor and classified by a convolutional neural network (CNN) considering the size information of each denomination. Experiments conducted on the combined banknote image database of six countries with 62 denominations gave a classification accuracy of 100%, and results show that our proposed algorithm outperforms previous methods. Full article

(This article belongs to the Section Physical Sensors)

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Open AccessArticle Leaf Area Index Estimation Using Chinese GF-1 Wide Field View Data in an Agriculture Region

by Xiangqin Wei, Xingfa Gu, Qingyan Meng, Tao Yu, Xiang Zhou, Zheng Wei, Kun Jia and Chunmei Wang

Sensors 2017, 17(7), 1593; doi:10.3390/s17071593

Received: 26 April 2017 / Revised: 20 June 2017 / Accepted: 5 July 2017 / Published: 8 July 2017

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Abstract

Leaf area index (LAI) is an important vegetation parameter that characterizes leaf density and canopy structure, and plays an important role in global change study, land surface process simulation and agriculture monitoring. The wide field view (WFV) sensor on board the Chinese GF-1

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Leaf area index (LAI) is an important vegetation parameter that characterizes leaf density and canopy structure, and plays an important role in global change study, land surface process simulation and agriculture monitoring. The wide field view (WFV) sensor on board the Chinese GF-1 satellite can acquire multi-spectral data with decametric spatial resolution, high temporal resolution and wide coverage, which are valuable data sources for dynamic monitoring of LAI. Therefore, an automatic LAI estimation algorithm for GF-1 WFV data was developed based on the radiative transfer model and LAI estimation accuracy of the developed algorithm was assessed in an agriculture region with maize as the dominated crop type. The radiative transfer model was firstly used to simulate the physical relationship between canopy reflectance and LAI under different soil and vegetation conditions, and then the training sample dataset was formed. Then, neural networks (NNs) were used to develop the LAI estimation algorithm using the training sample dataset. Green, red and near-infrared band reflectances of GF-1 WFV data were used as the input variables of the NNs, as well as the corresponding LAI was the output variable. The validation results using field LAI measurements in the agriculture region indicated that the LAI estimation algorithm could achieve satisfactory results (such as R² = 0.818, RMSE = 0.50). In addition, the developed LAI estimation algorithm had potential to operationally generate LAI datasets using GF-1 WFV land surface reflectance data, which could provide high spatial and temporal resolution LAI data for agriculture, ecosystem and environmental management researches. Full article

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

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Open AccessArticle A Study of Vicon System Positioning Performance

by Pierre Merriaux, Yohan Dupuis, Rémi Boutteau, Pascal Vasseur and Xavier Savatier

Sensors 2017, 17(7), 1591; doi:10.3390/s17071591

Received: 23 May 2017 / Revised: 4 July 2017 / Accepted: 5 July 2017 / Published: 7 July 2017

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Abstract

Motion capture setups are used in numerous fields. Studies based on motion capture data can be found in biomechanical, sport or animal science. Clinical science studies include gait analysis as well as balance, posture and motor control. Robotic applications encompass object tracking. Today’s

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Motion capture setups are used in numerous fields. Studies based on motion capture data can be found in biomechanical, sport or animal science. Clinical science studies include gait analysis as well as balance, posture and motor control. Robotic applications encompass object tracking. Today’s life applications includes entertainment or augmented reality. Still, few studies investigate the positioning performance of motion capture setups. In this paper, we study the positioning performance of one player in the optoelectronic motion capture based on markers: Vicon system. Our protocol includes evaluations of static and dynamic performances. Mean error as well as positioning variabilities are studied with calibrated ground truth setups that are not based on other motion capture modalities. We introduce a new setup that enables directly estimating the absolute positioning accuracy for dynamic experiments contrary to state-of-the art works that rely on inter-marker distances. The system performs well on static experiments with a mean absolute error of 0.15 mm and a variability lower than 0.025 mm. Our dynamic experiments were carried out at speeds found in real applications. Our work suggests that the system error is less than 2 mm. We also found that marker size and Vicon sampling rate must be carefully chosen with respect to the speed encountered in the application in order to reach optimal positioning performance that can go to 0.3 mm for our dynamic study. Full article

(This article belongs to the Section Physical Sensors)

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