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Special Issue "Selected Papers from the 2nd International Electronic Conference on Sensors and Applications"

A special issue of Sensors (ISSN 1424-8220).

Deadline for manuscript submissions: closed (31 March 2016)

Special Issue Editors

Guest Editor
Prof. Dr. Stefano Mariani

Department of Civil and Environmental Engineering, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy
Website | E-Mail
Phone: +39-0223994279
Fax: +39-0223994300
Interests: computational mechanics, fracture mechanics, extended Finite Element Method, Kalman and particle Filtering, topology optimization; MEMS; structural health monitoring
Guest Editor
Dr. Dirk Lehmhus

ISIS Sensorial Materials Scientific Centre, University of Bremen, 28359 Bremen, Germany
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Interests: porous and cellular metals, metal foams, syntactic foams, metal matrix syntactic foams, metal matrix composites, powder metallurgy, powder technology, finite element analysis, integrated computational materials engineering (ICME), smart structures, sensor integration, sensorial materials, structural health monitoring (SHM)
Guest Editor
Dr. Francesco Ciucci

Mechanical and Aerospace Engineering & Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology Clear Water Bay Kowloon, Hong Kong
Website | E-Mail
Fax: +852 2358 1543
Interests: solid state ionics, fuel cells, lithium batteries, chemical sensors
Guest Editor
Dr. Alberto Vallan

Politecnico di Torino, Department of Electronics and Telecommunications, corso Duca degli Abruzzi, 24, I-1029, Torino, Italy
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Interests: Fiber Optical Sensors, measurement science and technology, uncertainty evaluation
Guest Editor
Dr. Thomas Messervey

R2M Solution Scientific Research Laboratory ,Via Fratelli Cuzio 42, 27100 Pavia, Italy
Website | E-Mail
Interests: using sensor data to make better engineering decisions across design, assessment, maintenance, inspections, and energy management to include machine learning

Special Issue Information

Dear Colleagues,

This Special Issue comprises selected papers from the Proceedings of the 2nd International Electronic Conference on Sensors and Applications, held 15-30 November 2015 on sciforum.net, an online platform for hosting scholarly e-conferences and discussion groups. In this 2nd edition of the electronic conference, contributors were invited to provide papers and presentations from the field of sensors and applications at large, resulting in a wide variety of excellent submissions and topic areas. Selected papers which attracted the most interest on the web, or that provided a particularly innovative contribution, have been gathered for publication. These papers have been subjected to peer review and are published with the aim of rapid and wide dissemination of research results, developments and applications. We hope this Conference Series will grow rapidly in the future and become recognized as a new way and venue by which to (electronically) present new developments related to the field of sensors and their applications.

Dr. Stefano Mariani
Dr. Dirk Lehmhus
Dr. Francesco Ciucci
Dr. Alberto Vallan
Dr. Thomas B. Messervey
Guest Editor
s

Submission

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Sensors is an international peer-reviewed Open Access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Authors who have presented their article at the 2nd International Electronic Conference on Sensors and Applications will receive a 20% discount on the APC.

Keywords

  • biosensors
  • chemical sensors
  • physical sensors
  • sensor networks
  • applications
  • MEMS and NEMS
  • smart systems and structures
  • smart textiles
  • sports & sensors
  • factories of future
  • fiber sensors
  • sensing technologies for water resource management

Published Papers (25 papers)

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Open AccessArticle Implementation and Analysis of a Wireless Sensor Network-Based Pet Location Monitoring System for Domestic Scenarios
Sensors 2016, 16(9), 1384; doi:10.3390/s16091384
Received: 31 March 2016 / Revised: 30 June 2016 / Accepted: 15 August 2016 / Published: 30 August 2016
Cited by 1 | PDF Full-text (6647 KB) | HTML Full-text | XML Full-text
Abstract
The flexibility of new age wireless networks and the variety of sensors to measure a high number of variables, lead to new scenarios where anything can be monitored by small electronic devices, thereby implementing Wireless Sensor Networks (WSN). Thanks to ZigBee, RFID or
[...] Read more.
The flexibility of new age wireless networks and the variety of sensors to measure a high number of variables, lead to new scenarios where anything can be monitored by small electronic devices, thereby implementing Wireless Sensor Networks (WSN). Thanks to ZigBee, RFID or WiFi networks the precise location of humans or animals as well as some biological parameters can be known in real-time. However, since wireless sensors must be attached to biological tissues and they are highly dispersive, propagation of electromagnetic waves must be studied to deploy an efficient and well-working network. The main goal of this work is to study the influence of wireless channel limitations in the operation of a specific pet monitoring system, validated at physical channel as well as at functional level. In this sense, radio wave propagation produced by ZigBee devices operating at the ISM 2.4 GHz band is studied through an in-house developed 3D Ray Launching simulation tool, in order to analyze coverage/capacity relations for the optimal system selection as well as deployment strategy in terms of number of transceivers and location. Furthermore, a simplified dog model is developed for simulation code, considering not only its morphology but also its dielectric properties. Relevant wireless channel information such as power distribution, power delay profile and delay spread graphs are obtained providing an extensive wireless channel analysis. A functional dog monitoring system is presented, operating over the implemented ZigBee network and providing real time information to Android based devices. The proposed system can be scaled in order to consider different types of domestic pets as well as new user based functionalities. Full article
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Open AccessArticle A Smart Wearable Sensor System for Counter-Fighting Overweight in Teenagers
Sensors 2016, 16(8), 1220; doi:10.3390/s16081220
Received: 31 March 2016 / Revised: 5 July 2016 / Accepted: 26 July 2016 / Published: 10 August 2016
PDF Full-text (4463 KB) | HTML Full-text | XML Full-text
Abstract
PEGASO is a FP7-funded project whose goal is to develop an ICT and mobile-based platform together with an appropriate strategy to tackle the diffusion of obesity and other lifestyle-related illnesses among teenagers. Indeed, the design of an engaging strategy, leveraging a complementary set
[...] Read more.
PEGASO is a FP7-funded project whose goal is to develop an ICT and mobile-based platform together with an appropriate strategy to tackle the diffusion of obesity and other lifestyle-related illnesses among teenagers. Indeed, the design of an engaging strategy, leveraging a complementary set of technologies, is the approach proposed by the project to promote the adoption of healthy habits such as active lifestyle and balanced nutrition and to effectively counter-fight the emergence of overweight and obesity in the younger population. A technological key element of such a strategy sees the adoption of wearable sensors to monitor teenagers’ activities, which is at the basis of developing awareness about the current lifestyle. This paper describes the experience carried out in the framework of the PEGASO project in developing and evaluating wearable monitoring systems addressed to adolescents. The paper describes the methodological approach based on the co-designing of such a wearable system and the main results that, in the first phase, involved a total of 407 adolescents across Europe in a series of focus groups conducted in three countries for the requirements definition phase. Moreover, it describes an evaluation process of signal reliability during the usage of the wearable system. The main results described here are: (a) a prototype of the standardized experimental protocol that has been developed and applied to test signal reliability in smart garments; (b) the requirements definition methodology through a co-design activity and approach to address user requirements and preferences and not only technological specifications. Such co-design approach is able to support a higher system acceptance and usability together with a sustained adoption of the solution with respect to the traditional technology push system development strategy. Full article
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Open AccessArticle Implementation and Analysis of ISM 2.4 GHz Wireless Sensor Network Systems in Judo Training Venues
Sensors 2016, 16(8), 1247; doi:10.3390/s16081247
Received: 31 March 2016 / Revised: 27 July 2016 / Accepted: 2 August 2016 / Published: 6 August 2016
Cited by 1 | PDF Full-text (12905 KB) | HTML Full-text | XML Full-text
Abstract
In this work, the performance of ISM 2.4 GHz Wireless Sensor Networks (WSNs) deployed in judo training venues is analyzed. Judo is a very popular martial art, which is practiced by thousands of people not only at the competition level, but also as
[...] Read more.
In this work, the performance of ISM 2.4 GHz Wireless Sensor Networks (WSNs) deployed in judo training venues is analyzed. Judo is a very popular martial art, which is practiced by thousands of people not only at the competition level, but also as part of physical education programs at different school levels. There is a great variety of judo training venues, and each one has specific morphological aspects, making them unique scenarios in terms of radio propagation due to the presence of furniture, columns, equipment and the presence of human beings, which is a major issue as the person density within this kind of scenarios could be high. Another key aspect is the electromagnetic interference created by other wireless systems, such as WiFi or other WSNs, which make the radio planning a complex task in terms of coexistence. In order to analyze the impact of these features on the radio propagation and the performance of WSNs, an in-house developed 3D ray launching algorithm has been used. The obtained simulation results have been validated with a measurement campaign carried out in the sport facilities of the Public University of Navarre. The analysis is completed with the inclusion of an application designed to monitor biological constants of judokas, aimed to improve their training procedures. The application, that allows the simultaneous monitoring of multiple judokas (collective workouts) minimizing the efforts of the coach and medical supervisor, is based on commercial off-the-shelf products. The presented assessment of the presence of interfering wireless systems and the presence of human beings within judo training venues shows that an in-depth radio planning is required as these issues can have a great impact in the overall performance of a ISM 2.4 GHz WSN, affecting negatively the potential applications supported by wireless channel. Full article
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Open AccessArticle Transducer Development and Characterization for Underwater Acoustic Neutrino Detection Calibration
Sensors 2016, 16(8), 1210; doi:10.3390/s16081210
Received: 16 March 2016 / Revised: 14 July 2016 / Accepted: 26 July 2016 / Published: 2 August 2016
PDF Full-text (3259 KB) | HTML Full-text | XML Full-text
Abstract
A short bipolar pressure pulse with “pancake” directivity is produced and propagated when an Ultra-High Energy (UHE) neutrino interacts with a nucleus in water. Nowadays, acoustic sensor networks are being deployed in deep seas to detect this phenomenon as a first step toward
[...] Read more.
A short bipolar pressure pulse with “pancake” directivity is produced and propagated when an Ultra-High Energy (UHE) neutrino interacts with a nucleus in water. Nowadays, acoustic sensor networks are being deployed in deep seas to detect this phenomenon as a first step toward building a neutrino telescope. In order to study the feasibility of the method, it is critical to have a calibrator that is able to mimic the neutrino signature. In previous works the possibility of using the acoustic parametric technique for this aim was proven. In this study, the array is operated at a high frequency and, by means of the parametric effect, the emission of the low-frequency acoustic bipolar pulse is generated mimicking the UHE neutrino acoustic pulse. To this end, the development of the transducer to be used in the parametric array is described in all its phases. The transducer design process, the characterization tests for the bare piezoelectric ceramic, and the addition of backing and matching layers are presented. The efficiencies and directivity patterns obtained for both primary and parametric beams confirm that the design of the proposed calibrator meets all the requirements for the emitter. Full article
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Open AccessArticle Micromechanical Characterization of Polysilicon Films through On-Chip Tests
Sensors 2016, 16(8), 1191; doi:10.3390/s16081191
Received: 1 April 2016 / Revised: 21 June 2016 / Accepted: 26 July 2016 / Published: 28 July 2016
Cited by 5 | PDF Full-text (1127 KB) | HTML Full-text | XML Full-text
Abstract
When the dimensions of polycrystalline structures become comparable to the average grain size, some reliability issues can be reported for the moving parts of inertial microelectromechanical systems (MEMS). Not only the overall behavior of the device turns out to be affected by a
[...] Read more.
When the dimensions of polycrystalline structures become comparable to the average grain size, some reliability issues can be reported for the moving parts of inertial microelectromechanical systems (MEMS). Not only the overall behavior of the device turns out to be affected by a large scattering, but also the sensitivity to imperfections gets enhanced. In this work, through on-chip tests, we experimentally investigate the behavior of thin polysilicon samples using standard electrostatic actuation/sensing. The discrepancy between the target and actual responses of each sample has then been exploited to identify: (i) the overall stiffness of the film and, according to standard continuum elasticity, a morphology-based value of its Young’s modulus; (ii) the relevant over-etch induced by the fabrication process. To properly account for the aforementioned stochastic features at the micro-scale, the identification procedure has been based on particle filtering. A simple analytical reduced-order model of the moving structure has been also developed to account for the nonlinearities in the electrical field, up to pull-in. Results are reported for a set of ten film samples of constant slenderness, and the effects of different actuation mechanisms on the identified micromechanical features are thoroughly discussed. Full article
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Open AccessArticle Evaluation of Deployment Challenges of Wireless Sensor Networks at Signalized Intersections
Sensors 2016, 16(7), 1140; doi:10.3390/s16071140
Received: 31 March 2016 / Revised: 4 July 2016 / Accepted: 11 July 2016 / Published: 22 July 2016
Cited by 4 | PDF Full-text (29101 KB) | HTML Full-text | XML Full-text
Abstract
With the growing demand of Intelligent Transportation Systems (ITS) for safer and more efficient transportation, research on and development of such vehicular communication systems have increased considerably in the last years. The use of wireless networks in vehicular environments has grown exponentially. However,
[...] Read more.
With the growing demand of Intelligent Transportation Systems (ITS) for safer and more efficient transportation, research on and development of such vehicular communication systems have increased considerably in the last years. The use of wireless networks in vehicular environments has grown exponentially. However, it is highly important to analyze radio propagation prior to the deployment of a wireless sensor network in such complex scenarios. In this work, the radio wave characterization for ISM 2.4 GHz and 5 GHz Wireless Sensor Networks (WSNs) deployed taking advantage of the existence of traffic light infrastructure has been assessed. By means of an in-house developed 3D ray launching algorithm, the impact of topology as well as urban morphology of the environment has been analyzed, emulating the realistic operation in the framework of the scenario. The complexity of the scenario, which is an intersection city area with traffic lights, vehicles, people, buildings, vegetation and urban environment, makes necessary the channel characterization with accurate models before the deployment of wireless networks. A measurement campaign has been conducted emulating the interaction of the system, in the vicinity of pedestrians as well as nearby vehicles. A real time interactive application has been developed and tested in order to visualize and monitor traffic as well as pedestrian user location and behavior. Results show that the use of deterministic tools in WSN deployment can aid in providing optimal layouts in terms of coverage, capacity and energy efficiency of the network. Full article
Open AccessArticle Piezoresistive Membrane Surface Stress Sensors for Characterization of Breath Samples of Head and Neck Cancer Patients
Sensors 2016, 16(7), 1149; doi:10.3390/s16071149
Received: 29 February 2016 / Revised: 9 July 2016 / Accepted: 14 July 2016 / Published: 22 July 2016
Cited by 1 | PDF Full-text (7734 KB) | HTML Full-text | XML Full-text
Abstract
For many diseases, where a particular organ is affected, chemical by-products can be found in the patient’s exhaled breath. Breath analysis is often done using gas chromatography and mass spectrometry, but interpretation of results is difficult and time-consuming. We performed characterization of patients’
[...] Read more.
For many diseases, where a particular organ is affected, chemical by-products can be found in the patient’s exhaled breath. Breath analysis is often done using gas chromatography and mass spectrometry, but interpretation of results is difficult and time-consuming. We performed characterization of patients’ exhaled breath samples by an electronic nose technique based on an array of nanomechanical membrane sensors. Each membrane is coated with a different thin polymer layer. By pumping the exhaled breath into a measurement chamber, volatile organic compounds present in patients’ breath diffuse into the polymer layers and deform the membranes by changes in surface stress. The bending of the membranes is measured piezoresistively and the signals are converted into voltages. The sensor deflection pattern allows one to characterize the condition of the patient. In a clinical pilot study, we investigated breath samples from head and neck cancer patients and healthy control persons. Evaluation using principal component analysis (PCA) allowed a clear distinction between the two groups. As head and neck cancer can be completely removed by surgery, the breath of cured patients was investigated after surgery again and the results were similar to those of the healthy control group, indicating that surgery was successful. Full article
Open AccessArticle Identification of Water Bodies in a Landsat 8 OLI Image Using a J48 Decision Tree
Sensors 2016, 16(7), 1075; doi:10.3390/s16071075
Received: 21 March 2016 / Revised: 4 July 2016 / Accepted: 7 July 2016 / Published: 12 July 2016
Cited by 1 | PDF Full-text (3020 KB) | HTML Full-text | XML Full-text
Abstract
Water bodies are essential to humans and other forms of life. Identification of water bodies can be useful in various ways, including estimation of water availability, demarcation of flooded regions, change detection, and so on. In past decades, Landsat satellite sensors have been
[...] Read more.
Water bodies are essential to humans and other forms of life. Identification of water bodies can be useful in various ways, including estimation of water availability, demarcation of flooded regions, change detection, and so on. In past decades, Landsat satellite sensors have been used for land use classification and water body identification. Due to the introduction of a New Operational Land Imager (OLI) sensor on Landsat 8 with a high spectral resolution and improved signal-to-noise ratio, the quality of imagery sensed by Landsat 8 has improved, enabling better characterization of land cover and increased data size. Therefore, it is necessary to explore the most appropriate and practical water identification methods that take advantage of the improved image quality and use the fewest inputs based on the original OLI bands. The objective of the study is to explore the potential of a J48 decision tree (JDT) in identifying water bodies using reflectance bands from Landsat 8 OLI imagery. J48 is an open-source decision tree. The test site for the study is in the Northern Han River Basin, which is located in Gangwon province, Korea. Training data with individual bands were used to develop the JDT model and later applied to the whole study area. The performance of the model was statistically analysed using the kappa statistic and area under the curve (AUC). The results were compared with five other known water identification methods using a confusion matrix and related statistics. Almost all the methods showed high accuracy, and the JDT was successfully applied to the OLI image using only four bands, where the new additional deep blue band of OLI was found to have the third highest information gain. Thus, the JDT can be a good method for water body identification based on images with improved resolution and increased size. Full article
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Open AccessArticle A Flexible Optical pH Sensor Based on Polysulfone Membranes Coated with pH-Responsive Polyaniline Nanofibers
Sensors 2016, 16(7), 986; doi:10.3390/s16070986
Received: 9 March 2016 / Revised: 29 May 2016 / Accepted: 14 June 2016 / Published: 27 June 2016
Cited by 2 | PDF Full-text (4610 KB) | HTML Full-text | XML Full-text
Abstract
A new optical pH sensor based on polysulfone (PSU) and polyaniline (PANI) was developed. A transparent and flexible PSU membrane was employed as a support. The electrically conductive and pH-responsive PANI was deposited onto the membrane surface by in situ chemical oxidative polymerization
[...] Read more.
A new optical pH sensor based on polysulfone (PSU) and polyaniline (PANI) was developed. A transparent and flexible PSU membrane was employed as a support. The electrically conductive and pH-responsive PANI was deposited onto the membrane surface by in situ chemical oxidative polymerization (COP). The absorption spectra of the PANI-coated PSU membranes exhibited sensitivity to pH changes in the range of 4–12, which allowed for designing a dual wavelength pH optical sensor. The performance of the membranes was assessed by measuring their response starting from high pH and going down to low pH, and vice versa. It was found that it is necessary to precondition the sensor layers before each measurement due to the slight hysteresis observed during forward and backward pH titrations. PSU membranes with polyaniline coating thicknesses in the range of ≈100–200 nm exhibited fast response times of <4 s, which are attributed to the porous, rough and nanofibrillar morphology of the polyaniline coating. The fabricated pH sensor was characterized by a sigmoidal response (R2 = 0.997) which allows for pH determination over a wide dynamic range. All membranes were stable for a period of more than six months when stored in 1 M HCl solution. The reproducibility of the fabricated optical pH sensors was found to be <0.02 absorption units after one month storage in 1 M HCl solution. The performance of the optical pH sensor was tested and the obtained pH values were compared with the results obtained using a pH meter device. Full article
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Open AccessArticle Comparison of Metal-Backed Free-Space and Open-Ended Coaxial Probe Techniques for the Dielectric Characterization of Aeronautical Composites
Sensors 2016, 16(7), 967; doi:10.3390/s16070967
Received: 31 March 2016 / Revised: 17 June 2016 / Accepted: 20 June 2016 / Published: 24 June 2016
Cited by 2 | PDF Full-text (6893 KB) | HTML Full-text | XML Full-text
Abstract
The trend in the last few decades is that current unmanned aerial vehicles are completely made of composite materials rather than metallic, such as carbon-fiber or fiberglass composites. From the electromagnetic point of view, this fact forces engineers and scientists to assess how
[...] Read more.
The trend in the last few decades is that current unmanned aerial vehicles are completely made of composite materials rather than metallic, such as carbon-fiber or fiberglass composites. From the electromagnetic point of view, this fact forces engineers and scientists to assess how these materials may affect their radar response or their electronics in terms of electromagnetic compatibility. In order to evaluate this, electromagnetic characterization of different composite materials has become a need. Several techniques exist to perform this characterization, all of them based on the utilization of different sensors for measuring different parameters. In this paper, an implementation of the metal-backed free-space technique, based on the employment of antenna probes, is utilized for the characterization of composite materials that belong to an actual drone. Their extracted properties are compared with those given by a commercial solution, an open-ended coaxial probe (OECP). The discrepancies found between both techniques along with a further evaluation of the methodologies, including measurements with a split-cavity resonator, conclude that the implemented free-space technique provides more reliable results for this kind of composites than the OECP technique. Full article
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Open AccessArticle Smart Coat with a Fully-Embedded Textile Antenna for IoT Applications
Sensors 2016, 16(6), 938; doi:10.3390/s16060938
Received: 22 April 2016 / Revised: 2 June 2016 / Accepted: 17 June 2016 / Published: 22 June 2016
PDF Full-text (12497 KB) | HTML Full-text | XML Full-text
Abstract
The Internet of Things (IoT) scenario is strongly related with the advance of the development of wireless sensor networks (WSN) and radio frequency identification (RFID) systems. Additionally, in the WSN context, for a continuous feed, the integration of textile antennas for energy harvesting
[...] Read more.
The Internet of Things (IoT) scenario is strongly related with the advance of the development of wireless sensor networks (WSN) and radio frequency identification (RFID) systems. Additionally, in the WSN context, for a continuous feed, the integration of textile antennas for energy harvesting into smart clothing is a particularly interesting solution when the replacement of batteries is not easy to practice, such as in wearable devices. This paper presents the E-Caption: Smart and Sustainable Coat. It has an embedded dual-band textile antenna for electromagnetic energy harvesting, operating at global system for mobile communication (GSM) 900 and digital cellular system (DCS) 1800 bands. This printed antenna is fully integrated, as its dielectric is the textile material composing the coat itself. The E-Caption illustrates the innovative concept of textile antennas that can be manipulated as simple emblems. Seven prototypes of these “emblem” antennas, manufactured by lamination and embroidering techniques are also presented. It is shown that the orientation of the conductive fabric does not influence the performance of the antenna. It is also shown that the direction and number of the stitches in the embroidery may influence the performance of the antenna. Moreover, the comparison of results obtained before and after the integration of the antenna into cloth shows the integration does not affect the behavior of the antenna. Full article
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Open AccessArticle Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors
Sensors 2016, 16(6), 860; doi:10.3390/s16060860
Received: 17 March 2016 / Revised: 2 June 2016 / Accepted: 3 June 2016 / Published: 10 June 2016
Cited by 2 | PDF Full-text (6723 KB) | HTML Full-text | XML Full-text
Abstract
Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls
[...] Read more.
Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. With the aim of optimizing the sensor system, a test bench for the characterization of the sensors has been developed. The sensor response for different piezoelectric materials, geometries, matching layers, and backing layers have been measured and contrasted with FEM simulations and analytical models. The results of these studies lead us to have a design criterion for the construction of specific sensors for the next generation of dark matter bubble chamber detectors (250 L). Full article
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Open AccessArticle Defining Requirements and Related Methods for Designing Sensorized Garments
Sensors 2016, 16(6), 769; doi:10.3390/s16060769
Received: 11 March 2016 / Revised: 18 May 2016 / Accepted: 19 May 2016 / Published: 26 May 2016
Cited by 3 | PDF Full-text (2448 KB) | HTML Full-text | XML Full-text
Abstract
Designing smart garments has strong interdisciplinary implications, specifically related to user and technical requirements, but also because of the very different applications they have: medicine, sport and fitness, lifestyle monitoring, workplace and job conditions analysis, etc. This paper aims to discuss some user,
[...] Read more.
Designing smart garments has strong interdisciplinary implications, specifically related to user and technical requirements, but also because of the very different applications they have: medicine, sport and fitness, lifestyle monitoring, workplace and job conditions analysis, etc. This paper aims to discuss some user, textile, and technical issues to be faced in sensorized clothes development. In relation to the user, the main requirements are anthropometric, gender-related, and aesthetical. In terms of these requirements, the user’s age, the target application, and fashion trends cannot be ignored, because they determine the compliance with the wearable system. Regarding textile requirements, functional factors—also influencing user comfort—are elasticity and washability, while more technical properties are the stability of the chemical agents’ effects for preserving the sensors’ efficacy and reliability, and assuring the proper duration of the product for the complete life cycle. From the technical side, the physiological issues are the most important: skin conductance, tolerance, irritation, and the effect of sweat and perspiration are key factors for reliable sensing. Other technical features such as battery size and duration, and the form factor of the sensor collector, should be considered, as they affect aesthetical requirements, which have proven to be crucial, as well as comfort and wearability. Full article
Open AccessArticle Domotics Project Housing Block
Sensors 2016, 16(5), 741; doi:10.3390/s16050741
Received: 15 March 2016 / Revised: 10 May 2016 / Accepted: 17 May 2016 / Published: 23 May 2016
Cited by 1 | PDF Full-text (1702 KB) | HTML Full-text | XML Full-text
Abstract
This document develops the study of an implementation project of a home automation system in a housing placed in the town of Galapagar, Madrid. This house, which is going to be occupied by a four-member family, consists of 67 constructed square meters distributed
[...] Read more.
This document develops the study of an implementation project of a home automation system in a housing placed in the town of Galapagar, Madrid. This house, which is going to be occupied by a four-member family, consists of 67 constructed square meters distributed in lounge, kitchen, three bedrooms, bath, bathroom and terrace, this being a common arrangement in Spain. Thus, this study will allow extracting conclusions about the adequacy of the home automation in a wide percentage of housing in Spain. In this document, three house automation proposals are developed based on the requirements of the client and the different home automation levels that the Spanish House and Building Automation Association has established, besides two parallel proposals relating to the safety and the technical alarms. The mentioned proposed systems are described by means of product datasheets and descriptions, distribution plans, measurements, budgets and flow charts that describe the functioning of the system in every case. An evaluation of each system is included, based on other studies conclusions on this matter, where expected energy savings from each design, depending on the current cost of lighting, water and gas, as well as the expected economic amortization period is evaluated. Full article
Open AccessArticle Whole-Body Human Inverse Dynamics with Distributed Micro-Accelerometers, Gyros and Force Sensing
Sensors 2016, 16(5), 727; doi:10.3390/s16050727
Received: 31 March 2016 / Revised: 7 May 2016 / Accepted: 13 May 2016 / Published: 20 May 2016
Cited by 1 | PDF Full-text (2379 KB) | HTML Full-text | XML Full-text
Abstract
Human motion tracking is a powerful tool used in a large range of applications that require human movement analysis. Although it is a well-established technique, its main limitation is the lack of estimation of real-time kinetics information such as forces and torques during
[...] Read more.
Human motion tracking is a powerful tool used in a large range of applications that require human movement analysis. Although it is a well-established technique, its main limitation is the lack of estimation of real-time kinetics information such as forces and torques during the motion capture. In this paper, we present a novel approach for a human soft wearable force tracking for the simultaneous estimation of whole-body forces along with the motion. The early stage of our framework encompasses traditional passive marker based methods, inertial and contact force sensor modalities and harnesses a probabilistic computational technique for estimating dynamic quantities, originally proposed in the domain of humanoid robot control. We present experimental analysis on subjects performing a two degrees-of-freedom bowing task, and we estimate the motion and kinetics quantities. The results demonstrate the validity of the proposed method. We discuss the possible use of this technique in the design of a novel soft wearable force tracking device and its potential applications. Full article
Open AccessArticle Measurement of Moisture in Wood for Application in the Restoration of Old Buildings
Sensors 2016, 16(5), 697; doi:10.3390/s16050697
Received: 16 March 2016 / Revised: 5 May 2016 / Accepted: 11 May 2016 / Published: 14 May 2016
Cited by 2 | PDF Full-text (2221 KB) | HTML Full-text | XML Full-text
Abstract
There are many historic buildings whose construction is based on timber frame walls. Most buildings built during the nineteenth and early twentieth centuries were based on timber frame walls with vertical support elements. These timber frame elements are affected by their moisture content
[...] Read more.
There are many historic buildings whose construction is based on timber frame walls. Most buildings built during the nineteenth and early twentieth centuries were based on timber frame walls with vertical support elements. These timber frame elements are affected by their moisture content and by the passage of time. If the interaction of the timber frame walls with hygrothermal fluctuations were known, the maintenance of these buildings could be improved significantly. To determine the moisture content of wood there are two types of meters on the market: on the one hand, capacitance meters which consist of two side ends and where the moisture content is measured locally between two peaks. On the other hand, there are meters based on the variation of electromagnetic transmittance of timber, which depends on the moisture of timber. The second ones are very expensive and difficult to handle. This work presents a new non-intrusive capacitive sensor that measures the global moisture content in a section of the timber frame walls and therefore its accuracy is similar to the accuracy that can be obtained with electromagnetic transmittance meters. Additionally, as it is a capacitive sensor, it is low cost and easy to operate. Full article
Open AccessArticle Communication Range Dynamics and Performance Analysis for a Self-Adaptive Transmission Power Controller
Sensors 2016, 16(5), 684; doi:10.3390/s16050684
Received: 31 March 2016 / Revised: 2 May 2016 / Accepted: 5 May 2016 / Published: 12 May 2016
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Abstract
The deployment of the nodes in a Wireless Sensor and Actuator Network (WSAN) is typically restricted by the sensing and acting coverage. This implies that the locations of the nodes may be, and usually are, not optimal from the point of view of
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The deployment of the nodes in a Wireless Sensor and Actuator Network (WSAN) is typically restricted by the sensing and acting coverage. This implies that the locations of the nodes may be, and usually are, not optimal from the point of view of the radio communication. Additionally, when the transmission power is tuned for those locations, there are other unpredictable factors that can cause connectivity failures, like interferences, signal fading due to passing objects and, of course, radio irregularities. A control-based self-adaptive system is a typical solution to improve the energy consumption while keeping good connectivity. In this paper, we explore how the communication range for each node evolves along the iterations of an energy saving self-adaptive transmission power controller when using different parameter sets in an outdoor scenario, providing a WSAN that automatically adapts to surrounding changes keeping good connectivity. The results obtained in this paper show how the parameters with the best performance keep a k-connected network, where k is in the range of the desired node degree plus or minus a specified tolerance value. Full article
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Open AccessArticle Wearable Multi-Frequency and Multi-Segment Bioelectrical Impedance Spectroscopy for Unobtrusively Tracking Body Fluid Shifts during Physical Activity in Real-Field Applications: A Preliminary Study
Sensors 2016, 16(5), 673; doi:10.3390/s16050673
Received: 29 February 2016 / Revised: 18 April 2016 / Accepted: 4 May 2016 / Published: 11 May 2016
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Abstract
Bioelectrical Impedance Spectroscopy (BIS) allows assessing the composition of body districts noninvasively and quickly, potentially providing important physiological/clinical information. However, neither portable commercial instruments nor more advanced wearable prototypes simultaneously satisfy the demanding needs of unobtrusively tracking body fluid shifts in different segments
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Bioelectrical Impedance Spectroscopy (BIS) allows assessing the composition of body districts noninvasively and quickly, potentially providing important physiological/clinical information. However, neither portable commercial instruments nor more advanced wearable prototypes simultaneously satisfy the demanding needs of unobtrusively tracking body fluid shifts in different segments simultaneously, over a broad frequency range, for long periods and with high measurements rate. These needs are often required to evaluate exercise tests in sports or rehabilitation medicine, or to assess gravitational stresses in aerospace medicine. Therefore, the aim of this work is to present a new wearable prototype for monitoring multi-segment and multi-frequency BIS unobtrusively over long periods. Our prototype guarantees low weight, small size and low power consumption. An analog board with current-injecting and voltage-sensing electrodes across three body segments interfaces a digital board that generates square-wave current stimuli and computes impedance at 10 frequencies from 1 to 796 kHz. To evaluate the information derivable from our device, we monitored the BIS of three body segments in a volunteer before, during and after physical exercise and postural shift. We show that it can describe the dynamics of exercise-induced changes and the effect of a sit-to-stand maneuver in active and inactive muscular districts separately and simultaneously. Full article
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Open AccessArticle Vibration Monitoring Using Fiber Optic Sensors in a Lead-Bismuth Eutectic Cooled Nuclear Fuel Assembly
Sensors 2016, 16(4), 571; doi:10.3390/s16040571
Received: 26 February 2016 / Revised: 15 April 2016 / Accepted: 19 April 2016 / Published: 21 April 2016
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Abstract
Excessive fuel assembly vibrations in nuclear reactor cores should be avoided in order not to compromise the lifetime of the assembly and in order to prevent the occurrence of safety hazards. This issue is particularly relevant to new reactor designs that use liquid
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Excessive fuel assembly vibrations in nuclear reactor cores should be avoided in order not to compromise the lifetime of the assembly and in order to prevent the occurrence of safety hazards. This issue is particularly relevant to new reactor designs that use liquid metal coolants, such as, for example, a molten lead-bismuth eutectic. The flow of molten heavy metal around and through the fuel assembly may cause the latter to vibrate and hence suffer degradation as a result of, for example, fretting wear or mechanical fatigue. In this paper, we demonstrate the use of optical fiber sensors to measure the fuel assembly vibration in a lead-bismuth eutectic cooled installation which can be used as input to assess vibration-related safety hazards. We show that the vibration characteristics of the fuel pins in the fuel assembly can be experimentally determined with minimal intrusiveness and with high precision owing to the small dimensions and properties of the sensors. In particular, we were able to record local strain level differences of about 0.2 μϵ allowing us to reliably estimate the vibration amplitudes and modal parameters of the fuel assembly based on optical fiber sensor readings during different stages of the operation of the facility, including the onset of the coolant circulation and steady-state operation. Full article
Open AccessArticle Antenna Deployment for the Localization of Partial Discharges in Open-Air Substations
Sensors 2016, 16(4), 541; doi:10.3390/s16040541
Received: 29 February 2016 / Revised: 5 April 2016 / Accepted: 13 April 2016 / Published: 15 April 2016
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Abstract
Partial discharges are ionization processes inside or on the surface of dielectrics that can unveil insulation problems in electrical equipment. The charge accumulated is released under certain environmental and voltage conditions attacking the insulation both physically and chemically. The final consequence of a
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Partial discharges are ionization processes inside or on the surface of dielectrics that can unveil insulation problems in electrical equipment. The charge accumulated is released under certain environmental and voltage conditions attacking the insulation both physically and chemically. The final consequence of a continuous occurrence of these events is the breakdown of the dielectric. The electron avalanche provokes a derivative of the electric field with respect to time, creating an electromagnetic impulse that can be detected with antennas. The localization of the source helps in the identification of the piece of equipment that has to be decommissioned. This can be done by deploying antennas and calculating the time difference of arrival (TDOA) of the electromagnetic pulses. However, small errors in this parameter can lead to great displacements of the calculated position of the source. Usually, four antennas are used to find the source but the array geometry has to be correctly deployed to have minimal errors in the localization. This paper demonstrates, by an analysis based on simulation and also experimentally, that the most common layouts are not always the best options and proposes a simple antenna layout to reduce the systematic error in the TDOA calculation due to the positions of the antennas in the array. Full article
Open AccessArticle Performance Improvement of Total Ionization Dose Radiation Sensor Devices Using Fluorine-Treated MOHOS
Sensors 2016, 16(4), 450; doi:10.3390/s16040450
Received: 3 February 2016 / Revised: 18 March 2016 / Accepted: 23 March 2016 / Published: 29 March 2016
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Abstract
Fluorine-treated titanium nitride–silicon oxide–hafnium oxide–silicon oxide–silicon devices (hereafter F-MOHOS) are candidates for total ionization dose (TID) radiation sensor applications. The main subject of the study reportedherein is the performance improvement in terms of TID radiation-induced charge generation effect and charge-retention reliability characterization for
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Fluorine-treated titanium nitride–silicon oxide–hafnium oxide–silicon oxide–silicon devices (hereafter F-MOHOS) are candidates for total ionization dose (TID) radiation sensor applications. The main subject of the study reportedherein is the performance improvement in terms of TID radiation-induced charge generation effect and charge-retention reliability characterization for F-MOHOS devices. In the case of F-MOHOS TID radiation sensors, the gamma radiation induces a significant decrease of threshold voltage VT and the radiation-induced charge density is nearly six times larger than that of standard metal–oxide–nitride–oxide–silicon MONOS devices. The decrease of VT for F-MOHOS after gamma irradiation has a strong correlation to the TID up to 5 Mrad gamma irradiation as well. The improvement of charge retention loss for F-MOHOS devices is nearly 15% better than that of metal–oxide–hafnium oxide–oxide–silicon MOHOS devices. The F-MOHOS device described in this study demonstrates better feasibility for non-volatile TID radiation sensing in the future. Full article
Open AccessArticle An Evaluation of Sensor Performance for Harmful Compounds by Using Photo-Induced Electron Transfer from Photosynthetic Membranes to Electrodes
Sensors 2016, 16(4), 438; doi:10.3390/s16040438
Received: 25 January 2016 / Revised: 18 March 2016 / Accepted: 22 March 2016 / Published: 25 March 2016
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Abstract
Rapid, simple, and low-cost screening procedures are necessary for the detection of harmful compounds in the effluent that flows out of point sources such as industrial outfall. The present study investigated the effects on a novel sensor of harmful compounds such as KCN,
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Rapid, simple, and low-cost screening procedures are necessary for the detection of harmful compounds in the effluent that flows out of point sources such as industrial outfall. The present study investigated the effects on a novel sensor of harmful compounds such as KCN, phenol, and herbicides such as 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), 2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine (atrazine), and 2-N-tert-butyl-4-N-ethyl-6-methylsulfanyl-1,3,5-triazine-2,4-diamine (terbutryn). The sensor employed an electrode system that incorporated the photocurrent of intra-cytoplasmic membranes (so-called chromatophores) prepared from photosynthetic bacteria and linked using carbon paste electrodes. The amperometric curve (photocurrent-time curve) of photo-induced electron transfer from chromatophores of the purple photosynthetic bacterium Rhodobacter sphaeroides to the electrode via an exogenous electron acceptor was composed of two characteristic phases: an abrupt increase in current immediately after illumination (I0), and constant current over time (Ic). Compared with other redox compounds, 2,5-dichloro-1,4-benzoquinone (DCBQ) was the most useful exogenous electron acceptor in this system. Photo-reduction of DCBQ exhibited Michaelis-Menten-like kinetics, and reduction rates were dependent on the amount of DCBQ and the photon flux intensity. The Ic decreased in the presence of KCN at concentrations over 0.05 μM (=μmol·dm−3). The I0 decreased following the addition of phenol at concentrations over 20 μM. The Ic was affected by terbutryn at concentrations over 10 μM. In contrast, DCMU and atrazine had no effect on either I0 or Ic. The utility of this electrode system for the detection of harmful compounds is discussed. Full article
Open AccessArticle Online Condition Monitoring of Bearings to Support Total Productive Maintenance in the Packaging Materials Industry
Sensors 2016, 16(3), 316; doi:10.3390/s16030316
Received: 11 December 2015 / Revised: 19 February 2016 / Accepted: 25 February 2016 / Published: 1 March 2016
Cited by 3 | PDF Full-text (4146 KB) | HTML Full-text | XML Full-text
Abstract
The packaging materials industry has already recognized the importance of Total Productive Maintenance as a system of proactive techniques for improving equipment reliability. Bearing faults, which often occur gradually, represent one of the foremost causes of failures in the industry. Therefore, detection of
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The packaging materials industry has already recognized the importance of Total Productive Maintenance as a system of proactive techniques for improving equipment reliability. Bearing faults, which often occur gradually, represent one of the foremost causes of failures in the industry. Therefore, detection of their faults in an early stage is quite important to assure reliable and efficient operation. We present a new automated technique for early fault detection and diagnosis in rolling-element bearings based on vibration signal analysis. Following the wavelet decomposition of vibration signals into a few sub-bands of interest, the standard deviation of obtained wavelet coefficients is extracted as a representative feature. Then, the feature space dimension is optimally reduced to two using scatter matrices. In the reduced two-dimensional feature space the fault detection and diagnosis is carried out by quadratic classifiers. Accuracy of the technique has been tested on four classes of the recorded vibrations signals, i.e., normal, with the fault of inner race, outer race, and ball operation. The overall accuracy of 98.9% has been achieved. The new technique can be used to support maintenance decision-making processes and, thus, to increase reliability and efficiency in the industry by preventing unexpected faulty operation of bearings. Full article
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Open AccessArticle Data Mining and NIR Spectroscopy in Viticulture: Applications for Plant Phenotyping under Field Conditions
Sensors 2016, 16(2), 236; doi:10.3390/s16020236
Received: 2 December 2015 / Revised: 29 January 2016 / Accepted: 4 February 2016 / Published: 16 February 2016
Cited by 4 | PDF Full-text (409 KB) | HTML Full-text | XML Full-text
Abstract
Plant phenotyping is a very important topic in agriculture. In this context, data mining strategies may be applied to agricultural data retrieved with new non-invasive devices, with the aim of yielding useful, reliable and objective information. This work presents some applications of machine
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Plant phenotyping is a very important topic in agriculture. In this context, data mining strategies may be applied to agricultural data retrieved with new non-invasive devices, with the aim of yielding useful, reliable and objective information. This work presents some applications of machine learning algorithms along with in-field acquired NIR spectral data for plant phenotyping in viticulture, specifically for grapevine variety discrimination and assessment of plant water status. Support vector machine (SVM), rotation forests and M5 trees models were built using NIR spectra acquired in the field directly on the adaxial side of grapevine leaves, with a non-invasive portable spectrophotometer working in the spectral range between 1600 and 2400 nm. The ν-SVM algorithm was used for the training of a model for varietal classification. The classifiers’ performance for the 10 varieties reached, for cross- and external validations, the 88.7% and 92.5% marks, respectively. For water stress assessment, the models developed using the absorbance spectra of six varieties yielded the same determination coefficient for both cross- and external validations (R2 = 0.84; RMSEs of 0.164 and 0.165 MPa, respectively). Furthermore, a variety-specific model trained only with samples of Tempranillo from two different vintages yielded R2 = 0.76 and RMSE of 0.16 MPa for cross-validation and R2 = 0.79, RMSE of 0.17 MPa for external validation. These results show the power of the combined use of data mining and non-invasive NIR sensing for in-field grapevine phenotyping and their usefulness for the wine industry and precision viticulture implementations. Full article
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Open AccessConcept Paper Cloud-Based Automated Design and Additive Manufacturing: A Usage Data-Enabled Paradigm Shift
Sensors 2015, 15(12), 32079-32122; doi:10.3390/s151229905
Received: 4 November 2015 / Revised: 9 December 2015 / Accepted: 16 December 2015 / Published: 19 December 2015
Cited by 10 | PDF Full-text (5851 KB) | HTML Full-text | XML Full-text
Abstract
Integration of sensors into various kinds of products and machines provides access to in-depth usage information as basis for product optimization. Presently, this large potential for more user-friendly and efficient products is not being realized because (a) sensor integration and thus usage information
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Integration of sensors into various kinds of products and machines provides access to in-depth usage information as basis for product optimization. Presently, this large potential for more user-friendly and efficient products is not being realized because (a) sensor integration and thus usage information is not available on a large scale and (b) product optimization requires considerable efforts in terms of manpower and adaptation of production equipment. However, with the advent of cloud-based services and highly flexible additive manufacturing techniques, these obstacles are currently crumbling away at rapid pace. The present study explores the state of the art in gathering and evaluating product usage and life cycle data, additive manufacturing and sensor integration, automated design and cloud-based services in manufacturing. By joining and extrapolating development trends in these areas, it delimits the foundations of a manufacturing concept that will allow continuous and economically viable product optimization on a general, user group or individual user level. This projection is checked against three different application scenarios, each of which stresses different aspects of the underlying holistic concept. The following discussion identifies critical issues and research needs by adopting the relevant stakeholder perspectives. Full article

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