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Special Issue "I3S 2018 Selected Papers"

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

Deadline for manuscript submissions: closed (31 January 2019).

Special Issue Editors

Prof. Dr. Vladimir M. Mirsky
E-Mail Website
Guest Editor
Department of Nanobiotechnology, Institute of Biotechnology, Brandenburg University of Technology Cottbus-Senftenberg, 01968 Senftenberg, Germany
Interests: affinity biosensors; transducers for affinity biosensors; SPR; impedometric biosensors; capacitive biosensors; addressable immobilization of biomolecules
Prof. Dr. Gianluigi Ferrari
E-Mail Website
Guest Editor
Department of Engineering and Architecture, University of Parma, Parco Area delle Scienze, 181/A, 43124 Parma, Italy
Tel. (+39) 0521906513
Interests: communications; networking; signal processing; Internet of Things; smart systems
Special Issues and Collections in MDPI journals
Prof. Dr. Chien-Hung Liu
E-Mail Website
Guest Editor
Department of Mechanical Engineering, National Chung Hsing University, 250 Kuo Kuang Rd., Taichung 402, Taiwan
Fax: +886 4 2287 7170
Interests: high precision instrument design; laser engineering; smart sensors and actuators; optical device; optical measurement; metrology
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue was created in collaboration with the 6th International Symposium on Sensor Science (I3S 2018) and 4th SPINTECH Technology Thesis Award, held 6–8 August, 2018, in Kenting, Taiwan. It comprises six topical sessions that covers the most exciting aspects of sensor science (see below for a list of topics). The conference participants are cordially invited to contribute a full manuscript to this Special Issue and receive a 20% discount on the publishing fees.

Session 1: Physical Sensors
Session Chair: Prof. Dr. Bahram Nabet, Drexel University, USA

Session 2: Sensor Networks
Session Chair: Prof. Dr. Francisco Falcone, Universidad Publica de Navarra, UPNA, Spain

Session 3: Sensors Applications
Session Chair: Dr. Debbie G. Senesky, Stanford University, USA

Session 4: Biosensors
Session Chair: Prof. Dr. Michael J. Schöning, Aachen University of Applied Sciences, Germany

Session 5: Chemical Sessors
Session Chair: Prof. Dr. Vladimir M. Mirsky, Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg, Germany

Session 6: IoT Sensor and Application
Session Chair: Prof. Dr. Gianluigi Ferrari, University of Parma, Italy

Prof. Dr. Vladimir M. Mirsky
Prof. Dr. Gianluigi Ferrari
Prof. Dr. Chien-Hung Liu

Guest Editors

Manuscript Submission Information

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. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short 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 thoroughly refereed through a single-blind 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 semimonthly 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 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (21 papers)

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Research

Open AccessArticle
An Interoperable Access Control Framework for Diverse IoT Platforms Based on OAuth and Role
Sensors 2019, 19(8), 1884; https://doi.org/10.3390/s19081884 - 20 Apr 2019
Cited by 2
Abstract
Due to the rapid development of Internet of Things (IoT), IoT platforms that can provide common functions for things are becoming increasingly important. However, access control frameworks in diverse IoT platforms have been developed for individual security goals, designs, and technologies. In particular, [...] Read more.
Due to the rapid development of Internet of Things (IoT), IoT platforms that can provide common functions for things are becoming increasingly important. However, access control frameworks in diverse IoT platforms have been developed for individual security goals, designs, and technologies. In particular, current OAuth-based access control frameworks that are widely used in IoT research have not been providing interoperability among IoT platforms even though sharing resources and services is a critical issue for IoT platforms. Therefore, we analyze the main requirements for an IoT access control framework to properly design our framework and propose an interoperable access control framework based on OAuth 2.0 and Role. Our approach describes a new extended authorization grant flow to issue an Interoperable Access Token (IAT) that has a global access scope across IoT platforms using multiple pairs of clients’ credentials. With the IAT and proposed framework, we can access client-specific domains in heterogeneous IoT platforms, then valuable resources (e.g., data and services) in the domains can be accessed by validating the roles, which will greatly simplify permission management. Furthermore, IAT supports a simple token management (e.g., token issuance, refreshing, and revocation) by managing only one token for diverse IoT platforms. In addition, we implement our interoperable access control framework on Mobius and FIWARE, which are promising open-source IoT platforms, and test an interoperability scenario to demonstrate our approach with the implementation. Furthermore, the proposed framework is compared with other IoT access control approaches based on the selected requirements in this paper. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Quasi-Static Current Measurement with Field-Modulated Spin-Valve GMR Sensors
Sensors 2019, 19(8), 1882; https://doi.org/10.3390/s19081882 - 20 Apr 2019
Abstract
A non-contact current measurement device comprised of a GMR sensor and a ferrite ring core was investigated. The sensor chip employed a high-sensitivity spin-valve full-bridge GMR sensor of which the direct output has non-negligible hysteresis and a limited linear range. By applying an [...] Read more.
A non-contact current measurement device comprised of a GMR sensor and a ferrite ring core was investigated. The sensor chip employed a high-sensitivity spin-valve full-bridge GMR sensor of which the direct output has non-negligible hysteresis and a limited linear range. By applying an AC modulation current to modulate the output of the GMR sensor, the hysteresis was reduced, and the linear range was over ±0.5 A. The resolution for DC and quasi-static current measurement was 0.1 mA at a 10 Hz bandwidth. The output in proportion to the measured current was obtained either by demodulating the current-sensitive AC signal or by employing the filtered output of the intrinsically nonlinear spin-valve response. The proposed current sensing scheme is suitable for quasi-static current measurement from DC to over 100 Hz. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Distributed Sensing Based on Interferometry and Polarization Methods for Use in Fibre Infrastructure Protection
Sensors 2019, 19(8), 1810; https://doi.org/10.3390/s19081810 - 16 Apr 2019
Abstract
Fibre optic infrastructures are very important, and therefore, it is necessary to protect them from fibre cuts. Most fibre cuts are caused by digging activity, and many network operators seek appropriate solutions enabling detection of possible unexpected events (predict these cuts) and subsequent [...] Read more.
Fibre optic infrastructures are very important, and therefore, it is necessary to protect them from fibre cuts. Most fibre cuts are caused by digging activity, and many network operators seek appropriate solutions enabling detection of possible unexpected events (predict these cuts) and subsequent network outages. In most cases, there is no need to locate events, and only information regarding the occurrence of the event is sufficient. Direct detection-based distributed fibre optic sensing systems appear to be an appropriate solution, allowing digging to be detected before the fibre breaks. The average power of such signals is relatively small, and there is no interference with other signals in the fibre. We performed laboratory measurements to compare the sensitivity and accuracy of interferometric and polarization systems for acoustic vibrations. In the case of interferometric systems, the reference and sensing arms were in the same cable, and both were subjected to acoustic vibrations. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
On the Image Sensor Processing for Lane Detection and Control in Vehicle Lane Keeping Systems
Sensors 2019, 19(7), 1665; https://doi.org/10.3390/s19071665 - 08 Apr 2019
Cited by 1
Abstract
Lane keeping systems for a keeping a vehicle in the desired lane is key to advanced driving assistance system in autonomous vehicles. This paper presents a cost-effective image sensor with efficient processing algorithm for lane detection and lane control applications to autonomous delivery [...] Read more.
Lane keeping systems for a keeping a vehicle in the desired lane is key to advanced driving assistance system in autonomous vehicles. This paper presents a cost-effective image sensor with efficient processing algorithm for lane detection and lane control applications to autonomous delivery systems. The algorithm includes (1) lane detection by inverse perspective mapping and random sample consensus parabola fitting and (2) lane control by pure pursuit steering controller and classical proportional integral speed controller based on a nonholonomic kinematic model. The image sensor experiments conducted on a 1/10 scale model car maneuvering in a straight–curve–straight lane validate the better processing performance before, during, and after the turning section over previous work. The image sensor with the processing algorithm achieves the average lane detection error within 5% and maximum cross-track error within 9% in real-time. The development shall pave the way to cost-effective autonomous delivery systems. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Simultaneous Transmission of Photonic Services over One Fiber with an ITU 100 GHz Grid
Sensors 2019, 19(7), 1601; https://doi.org/10.3390/s19071601 - 02 Apr 2019
Abstract
The increasing interest in distributed sensors and the decreasing price of optical components have led to leveraging the use of existing fiber in deployments over optical networks and more application possibilities (from seismic activity measurement to perimeter protection and tunnel fire detection). Because [...] Read more.
The increasing interest in distributed sensors and the decreasing price of optical components have led to leveraging the use of existing fiber in deployments over optical networks and more application possibilities (from seismic activity measurement to perimeter protection and tunnel fire detection). Because of the possibility of data interference in single fibers, dark fibers are used. On the one hand, optical networks are able to transfer popular services, such as streaming and data transmission, and on the other hand, special advanced services such as an accurate time, a stable frequency, and high-power optical sensor signals can be provided. In our work, we address the simultaneous transmission of an accurate time, 100 G data, and a high-power optical sensor based on Phase-sensitive optical time domain reflectometer ( Φ -OTDR). The measurement setup consists of the optical fiber G.652 (7 km), G.653 (7 km), and G.655 (10 km) and a combination of G.652D + G.653 (14 km). Moreover, we also provide results for their combination. The services were transferred in single fiber with an ITU 100 GHz channel spacing grid. We performed a set of measurements with an evaluation of the BER value for data transmission affected by a high-power sensor system and accurate time values. The results confirmed our assumptions that 100 GHz spacing is not large enough, especially with the increasing power level of the sensor system. The main aim of the article is to determine whether data are disturbed with normal 100 GHz channel spacing. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Peak Detection Algorithm for Vital Sign Detection Using Doppler Radar Sensors
Sensors 2019, 19(7), 1575; https://doi.org/10.3390/s19071575 - 01 Apr 2019
Cited by 2
Abstract
An accurate method for detecting vital signs obtained from a Doppler radar sensor is proposed. A Doppler radar sensor can remotely obtain vital signs such as heartbeat and respiration rate, but the vital signs obtained by using the sensor do not show clear [...] Read more.
An accurate method for detecting vital signs obtained from a Doppler radar sensor is proposed. A Doppler radar sensor can remotely obtain vital signs such as heartbeat and respiration rate, but the vital signs obtained by using the sensor do not show clear peaks like in electrocardiography (ECG) because of the operating characteristics of the radar. The proposed peak detection algorithm extracts the vital signs from the raw data. The algorithm shows the mean accuracy of 96.78% compared to the peak count from the reference ECG sensor and a processing time approximately two times faster than the gradient-based algorithm. To verify whether heart rate variability (HRV) analysis similar to that with an ECG sensor is possible for a radar sensor when applying the proposed method, the continuous parameter variations of the HRV in the time domain are analyzed using data processed with the proposed peak detection algorithm. Experimental results with six subjects show that the proposed method can obtain the heart rate with high accuracy but cannot obtain the information for an HRV analysis because the proposed method cannot overcome the characteristics of the radar sensor itself. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Performance Improvement of a Nonvolatile UV TD Sensor Using SAHAOS with a High Temperature Annealed, Partially Nano-Crystallized Trapping Layer
Sensors 2019, 19(7), 1570; https://doi.org/10.3390/s19071570 - 01 Apr 2019
Abstract
This study shows that a silicon–aluminum oxide–hafnium aluminum oxide-silicon oxide–silicon capacitor device with a high temperature pre-metal-anneal-treated and partially-nanocrystallized hafnium aluminum oxide, (hereafter PNC-SAHAOS) can successfully increase the performance of a nonvolatile ultraviolet radiation total dose (hereafter UV TD) sensor. The experimental results [...] Read more.
This study shows that a silicon–aluminum oxide–hafnium aluminum oxide-silicon oxide–silicon capacitor device with a high temperature pre-metal-anneal-treated and partially-nanocrystallized hafnium aluminum oxide, (hereafter PNC-SAHAOS) can successfully increase the performance of a nonvolatile ultraviolet radiation total dose (hereafter UV TD) sensor. The experimental results show that the UV-induced threshold voltage VT shift of PNC-SAHAOS was 10 V after UV TD 100 mW·s/cm2 irradiation. The UV-induced charge density of PNC-SAHAOS is almost eight times that of amorphous silicon–aluminum oxide–silicon nitride–silicon dioxide–silicon SANOS. Moreover, the charge fading rate of ten-years retention on PNC-SAHAOS, even at 85 °C, is below 10%. At 85 °C, the charge fading rate of ten-years retention on amorphous SANOS is almost twice that on PNC-SAHAOS. These results strongly suggest that PNC-SAHAOS could be the most promising candidate for next-generation nonvolatile UV TD sensor technology. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Quasi-static Analysis Based on an Equivalent Circuit Model for a CMOS Terahertz Plasmon Detector in the Subthreshold Region
Sensors 2019, 19(7), 1508; https://doi.org/10.3390/s19071508 - 28 Mar 2019
Abstract
An analytic method for a complementary metal-oxide-semiconductor (CMOS) terahertz plasmon detector operating in the subthreshold region is presented using the equivalent circuit model. With respect to design optimization of the detector, the signal transmission from the antenna port to the output of the [...] Read more.
An analytic method for a complementary metal-oxide-semiconductor (CMOS) terahertz plasmon detector operating in the subthreshold region is presented using the equivalent circuit model. With respect to design optimization of the detector, the signal transmission from the antenna port to the output of the detector is described by using the proposed circuit model, which does not include a complicated physical operating principle and mathematical expressions. Characteristics from the antenna port to the input gate node of the detector are analyzed through the superposition method by using the characteristic impedance of transmission lines. The superposition method shows that the effect of interconnection lines at the input is simplified with the optimum bias point. The characteristics of the plasmon detection are expressed by using small-signal analysis of the single transistor at the sub-threshold operation. The results of the small-signal analysis show that the unity gain preamplifier located between the detector core and the main amplifier can improve the detection performances such as the voltage responsivity and the noise equivalent power. The measurement results using the fabricated CMOS plasmon detector at 200 GHz suggest that the unity gain preamplifier improves the detector performances, which are the same results as we received from the proposed analytic method. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Investigation of Electrical Stability and Sensitivity of Electric Double Layer Gated Field-Effect Transistors (FETs) for miRNA Detection
Sensors 2019, 19(7), 1484; https://doi.org/10.3390/s19071484 - 27 Mar 2019
Cited by 1
Abstract
In this research, we developed a miRNA sensor using an electrical double layer (EDL) gated field-effect transistor (FET)-based biosensor with enhanced sensitivity and stability. We conducted an in-depth investigation of the mechanisms that give rise to fluctuations in the electrical signal, affecting the [...] Read more.
In this research, we developed a miRNA sensor using an electrical double layer (EDL) gated field-effect transistor (FET)-based biosensor with enhanced sensitivity and stability. We conducted an in-depth investigation of the mechanisms that give rise to fluctuations in the electrical signal, affecting the stability and sensitivity of the miRNA sensor. Firstly, surface characteristics were studied by examining the metal electrodes deposited using different metal deposition techniques. The lower surface roughness of the gold electrode improved the electrical current stability. The temperature and viscosity of the sample solution were proven to affect the electrical stability, which was attributed to reducing the effect of Brownian motion. Therefore, by controlling the test conditions, such as temperature and sample viscosity, and the surface characteristics of the metal electrodes, we can enhance the stability of the sensor. Metal electrodes deposited via sputtering and e-beam evaporator yielded the lowest signal fluctuation. When ambient temperature was reduced to 3 °C, the sensor had better noise characteristics compared to room temperature testing. Higher viscosity of samples resulted in lower signal fluctuations. Lastly, surface functionalization was demonstrated to be a critical factor in enhancing the stability and sensitivity. MiRNA sensors with higher surface ratios of immobilized DNA probes performed with higher sensitivity and stability. This study reveals methods to improve the characteristics of EDL FET biosensors to facilitate practical implementation in clinical applications. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Optical Inspection System for Gear Tooth Surfaces Using a Projection Moiré Method
Sensors 2019, 19(6), 1450; https://doi.org/10.3390/s19061450 - 25 Mar 2019
Cited by 2
Abstract
The demand for rapid online optical inspection of gear tooth surfaces is increasing, especially for precision gears. In this study, a non-contact optical measurement method was established for the inspection of gear tooth surfaces. For the system architecture, a halogen lamp was selected [...] Read more.
The demand for rapid online optical inspection of gear tooth surfaces is increasing, especially for precision gears. In this study, a non-contact optical measurement method was established for the inspection of gear tooth surfaces. For the system architecture, a halogen lamp was selected as the light source, and a collimated beam was produced by an autocollimator. Subsequently, moiré fringes were formed as the collimated beam went through the two linear gratings. The moiré fringes projected on the gear tooth surface were recorded with a charge-coupled device (CCD) camera, and the contour of the gear tooth surface was estimated and reconstructed from the phase information of the fringes by our developed computer codes. To verify the accuracy of the system, a spur gear tooth surface measured by a commercial coordinate measuring machine (CMM) was defined as the reference tooth profile. The tooth topography, involute profile deviation, and axial-direction deviation were successfully calculated by measuring the deviation of the optically measured surface based on the reference gear tooth profiles measured using the CMM. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Device Identification Interoperability in Heterogeneous IoT Platforms
Sensors 2019, 19(6), 1433; https://doi.org/10.3390/s19061433 - 23 Mar 2019
Cited by 1
Abstract
With the continuous improvement of Internet of Things (IoT) technologies, various IoT platforms are under development. However, each IoT platform is developed based on its own device identification system. That is, it is challenging to identify each sensor device between heterogeneous IoT platforms [...] Read more.
With the continuous improvement of Internet of Things (IoT) technologies, various IoT platforms are under development. However, each IoT platform is developed based on its own device identification system. That is, it is challenging to identify each sensor device between heterogeneous IoT platforms owing to the resource request format (e.g., device identifier) varying between platforms. Moreover, despite the considerable research focusing on resource interoperability between heterogeneous IoT platforms, little attention is given to sensor device identification systems in diverse IoT platforms. In order to overcome this problem, the current work proposes an IoT device name system (DNS) architecture based on the comparative analysis of heterogeneous IoT platforms (i.e., oneM2M, GS1 ‘Oliot’, IBM ‘Watson IoT’, OCF ‘IoTivity’, FIWARE). The proposed IoT DNS analyzes and translates the identification system of the device and resource request format. In this process, resource requests between heterogeneous IoT platforms can be reconfigured appropriately for the resources and services requested by the user, and as a result, users can use heterogeneous IoT services. Furthermore, in order to illustrate the aim of the proposed architecture, the proposed IoT DNS is implemented and tested on a microcomputer. The experimental results show that a oneM2M-based device successfully performs a resource request to a Watson IoT and FIWARE sensor devices. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Use of Multi-Agent Theory to Resolve Complex Indoor Air Quality Control Problems
Sensors 2019, 19(5), 1206; https://doi.org/10.3390/s19051206 - 09 Mar 2019
Abstract
Taiwan has suffered from widespread haze and poor air quality during recent years, and the control of indoor air quality has become an important topic. This study relies on Multi-Agent theory in which collected air quality was used in calculations and after agents [...] Read more.
Taiwan has suffered from widespread haze and poor air quality during recent years, and the control of indoor air quality has become an important topic. This study relies on Multi-Agent theory in which collected air quality was used in calculations and after agents make decisions in accordance with pre-written rules to construct and indoor air quality control system and conflict resolution mechanism, which will serve to maintain a healthy and comfortable indoor environment. As for implementation, the simulated system used the Arduino open source microcontroller system to collect air quality data and turn on building equipment in order to improve indoor air quality. This study also used the graphic control program LabVIEW to write a control program and user interface. The implementation verifies the feasibility of applying multi-agent theory to air quality control systems, and an Individual intelligent agent has the basic ability to resolve their own conflicts autonomously. However, when there are multiple factors and user status are simultaneously involved in the decision-making, it is difficult for the system to exhaust all conflict conditions, and when context control surpassing the restrictions of binary logic rule-based reasoning, it is necessary to change the algorithm and redesign the system. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
3D LiDAR-Based Precision Vehicle Localization with Movable Region Constraints
Sensors 2019, 19(4), 942; https://doi.org/10.3390/s19040942 - 22 Feb 2019
Cited by 3
Abstract
This paper discusses a high-performance similarity measurement method based on known map information named the cross mean absolute difference (CMAD) method. Applying the conventional normalized cross-correlation (NCC) feature registration method requires sufficient numbers of feature points, which must also exhibit near-normal distribution. However, [...] Read more.
This paper discusses a high-performance similarity measurement method based on known map information named the cross mean absolute difference (CMAD) method. Applying the conventional normalized cross-correlation (NCC) feature registration method requires sufficient numbers of feature points, which must also exhibit near-normal distribution. However, Light Detection and Ranging (LiDAR) ranging point cloud data scanned and collected on-site are scarce and do not fulfill near-normal distribution. Consequently, considerable localization errors occur when NCC features are registered with map features. Thus, the CMAD method was proposed to effectively improve the NCC algorithm and localization accuracy. Because uncertainties in localization sensors cause deviations in the localization processes, drivable moving regions (DMRs) were established to restrict the range of location searches, filter out unreasonable trajectories, and improve localization speed and performance. An error comparison was conducted between the localization results of the window-based, DMR–CMAD, and DMR–NCC methods, as well as those of the simultaneous localization and mapping methods. The DMR–CMAD method did not differ considerably from the window-based method in its accuracy: the root mean square error in the indoor experiment was no higher than 10 cm, and that of the outdoor experiment was 10–30 cm. Additionally, the DMR–CMAD method was the least time-consuming of the three methods, and the DMR–NCC generated more localization errors and required more localization time than the other two methods. Finally, the DMR–CMAD algorithm was employed for the successful on-site instant localization of a car. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Development of a Wireless Mesh Sensing System with High-Sensitivity LiNbO3 Vibration Sensors for Robotic Arm Monitoring
Sensors 2019, 19(3), 507; https://doi.org/10.3390/s19030507 - 26 Jan 2019
Cited by 1
Abstract
In recent years, multi-axis robots are indispensable in automated factories due to the rapid development of Industry 4.0. Many related processes were required to have the increasing demand for accuracy, reproducibility, and abnormal detection. The monitoring function and immediate feedback for correction is [...] Read more.
In recent years, multi-axis robots are indispensable in automated factories due to the rapid development of Industry 4.0. Many related processes were required to have the increasing demand for accuracy, reproducibility, and abnormal detection. The monitoring function and immediate feedback for correction is more and more important. This present study integrated a highly sensitive lithium niobate (LiNbO3) vibration sensor as a sensor node (SN) and architecture of wireless mesh network (WMN) to develop a monitoring system (MS) for the robotic arm. The advantages of the thin-film LiNbO3 piezoelectric sensor were low-cost, high-sensitivity and good electrical compatibility. The experimental results obtained from the vibration platform show that the sensitivity achieved 50 mV/g and the reaction time within 1 ms. The results of on-site testing indicated that the SN could be configured on the relevant equipment quickly and detect the abnormal vibration in specific equipment effectively. Each SN could be used more than 10 h at the 80 Hz transmission rate under WMN architecture and the loss rate of transmission was less than 0.01% within 20 m. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Visual-Acoustic Sensor-Aided Sorting Efficiency Optimization of Automotive Shredder Polymer Residues Using Circularity Determination
Sensors 2019, 19(2), 284; https://doi.org/10.3390/s19020284 - 12 Jan 2019
Abstract
To reduce the emissions and weight of vehicles, manufacturers are incorporating polymer materials into vehicles, and this has increased the difficulty in recycling End-of-Life vehicles (ELVs). About 25–30% (mass) of an ELV crushed mixture is the unrecyclable material known as automotive shredder residues [...] Read more.
To reduce the emissions and weight of vehicles, manufacturers are incorporating polymer materials into vehicles, and this has increased the difficulty in recycling End-of-Life vehicles (ELVs). About 25–30% (mass) of an ELV crushed mixture is the unrecyclable material known as automotive shredder residues (ASRs), and most of the vehicle polymers are concentrated in this fraction. Thus, these vehicle polymers are conventionally disposed of in landfills at a high risk to the environment. The only way to solve this problem is through the development of a novel separation and recycling mechanism for ASRs. Our previous research reported a novel sensor-aided single-scrap-oriented sorting method that uses laser-triangulation imaging combined with impact acoustic frequency recognition for sorting crushed ASR plastics, and we proved its feasibility. However, the sorting efficiencies were still limited, since, in previous studies, the method used for scrap size determination was mechanical sieving, resulting in many deviations. In this paper, a new method based on three-dimensional (3D) imaging and circularity analysis is proposed to determine the equivalent particle size with much greater accuracy by avoiding the issues that are presented by the irregularity of crushed scraps. In this research, two kinds of commonly used vehicle plastics, acrylonitrile-butadiene-styrene (ABS) and polypropylene (PP), and their corresponding composite materials, acrylonitrile-butadiene-styrene/polycarbonate (ABS/PC) and polypropylene/ethylene-propylene-diene-monomer (PP/EPDM), were studied. When compared with our previous study, with this new method, the sorting efficiency increased, with PP and PP/EPDM and ABS and ABS/PC achieving about 15% and 20% and 70% and 90%, respectively. The sorting efficiency of ASR polymer scraps can be optimized significantly by using sensor-aided 3D image measurement and circularity analysis. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Battery Charger Prototype Design for Tire Pressure Sensor Battery Recharging
Sensors 2019, 19(1), 124; https://doi.org/10.3390/s19010124 - 02 Jan 2019
Abstract
One of the important devices in a vehicle is the tire pressure sensor. This device couples with other instruments inside the vehicle assisting the drivers in knowing the correct information about their vehicle’s tire pressure. This information helps improve vehicle handling, increases gas [...] Read more.
One of the important devices in a vehicle is the tire pressure sensor. This device couples with other instruments inside the vehicle assisting the drivers in knowing the correct information about their vehicle’s tire pressure. This information helps improve vehicle handling, increases gas mileage, and extends tire lifespan. Once mounted inside the tire, the tire pressure sensor is a stand-alone device. It is powered by a battery that has a limited operating life. Due to it being mounted inside the tire, the driver does not frequently check tire pressure sensor battery. If the battery runs out, battery replacement is not an effective option. This work presents a battery charging prototype that recharges the tire pressure sensor battery. The developed device uses electromagnetic principles to wirelessly transmit power to a device that needs power. We designed a prototype and conducted some laboratory scale experiments. Experimental and validation were based on a tire pressure sensor developed by Kenda Rubber Ind. Co., Ltd, Taiwan (R.O.C). This tire pressure sensor consumes power from a 4.8 V 700 mAh Li-ion rechargeable battery. The experimental results show that the prototype can transmit 4.9 V induction voltage. The maximum current is up to 850 mA with the optimum transmission distance at around of 1.5 cm. This prototype recharges the tire pressure sensor battery wirelessly to extend its battery-power life. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Design of a Measurement System for Simultaneously Measuring Six-Degree-Of-Freedom Geometric Errors of a Long Linear Stage
Sensors 2018, 18(11), 3875; https://doi.org/10.3390/s18113875 - 10 Nov 2018
Cited by 6
Abstract
This study designs and characterizes a novel precise measurement system for simultaneously measuring six-degree-of-freedom geometric motion errors of a long linear stage of a machine tool. The proposed measurement system is based on a method combined with the geometrical optics method and laser [...] Read more.
This study designs and characterizes a novel precise measurement system for simultaneously measuring six-degree-of-freedom geometric motion errors of a long linear stage of a machine tool. The proposed measurement system is based on a method combined with the geometrical optics method and laser interferometer method. In contrast to conventional laser interferometers using only the interferometer method, the proposed measurement system can simultaneously measure six-degree-of-freedom geometric motion errors of a long linear stage with lower cost and faster operational time. The proposed measurement system is characterized numerically using commercial software ZEMAX and mathematical modeling established by using a skew-ray tracing method, a homogeneous transformation matrix, and a first-order Taylor series expansion. The proposed measurement system is then verified experimentally using a laboratory-built prototype. The experimental results show that, compared to conventional laser interferometers, the proposed measurement system better achieves the ability to simultaneously measure six-degree-of-freedom geometric errors of a long linear stage (a traveling range of 250 mm). Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
A Smart Pillow for Health Sensing System Based on Temperature and Humidity Sensors
Sensors 2018, 18(11), 3664; https://doi.org/10.3390/s18113664 - 29 Oct 2018
Cited by 3
Abstract
The quality of sleep affects the patient’s health, along with the observation of vital life signs such as body temperature and sweat in sleep, is essential in the monitoring of sleep as well as clinical diagnosis. However, traditional methods in recording physiological change [...] Read more.
The quality of sleep affects the patient’s health, along with the observation of vital life signs such as body temperature and sweat in sleep, is essential in the monitoring of sleep as well as clinical diagnosis. However, traditional methods in recording physiological change amidst sleep is difficult without being intrusive. The smart pillow is developed to provide a relatively easy way to observe one’s sleep condition, employing temperature and humidity sensors by implanting them inside the pillow in strategic positions. With the patient’s head on the pillow, the roles of sensors are identified as main, auxiliary or environmental temperature, based on the differences of value from three temperature sensors, thus the pattern of sleep can be extracted by statistical analysis, and the body temperature is inferred by a specially designed Fuzzy Logic System if the head-on position is stable for more than 15 min. Night sweat is reported on data from the humidity sensor. Therefore, a cloud-based health-sensing system is built in the smart pillow to collect and analyze data. Experiments from various individuals prove that statistical and inferred results reflect normal and abnormal conditions of sleep accurately. The daily sleeping information of patients from the pillow is helpful in the decision-making of diagnoses and treatment, and users can change their habits of sleep gradually by observing the data with their health professional. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Birefringent Bragg Grating in C-Shaped Optical Fiber as a Temperature-Insensitive Refractometer
Sensors 2018, 18(10), 3285; https://doi.org/10.3390/s18103285 - 29 Sep 2018
Cited by 5
Abstract
We demonstrate a simple-to-fabricate refractometer based on the inscription of fiber Bragg gratings in a special C-shaped optical fiber. The C-shaped fiber was drawn into shape using a quarter cladding removed preform of a commercial standard single-mode fiber by simple machining. The sensor [...] Read more.
We demonstrate a simple-to-fabricate refractometer based on the inscription of fiber Bragg gratings in a special C-shaped optical fiber. The C-shaped fiber was drawn into shape using a quarter cladding removed preform of a commercial standard single-mode fiber by simple machining. The sensor did not suffer from cross-sensitivity of the refractive index with ambient temperature fluctuations, commonly occurring with many optical fiber refractometers. A refractive index sensitivity of 1300 pm per refractive index unit (RIU) was achieved without employing any additional sensitization techniques such as tapering or etching. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Double Notched Long-Period Fiber Grating Characterization for CO2 Gas Sensing Applications
Sensors 2018, 18(10), 3206; https://doi.org/10.3390/s18103206 - 22 Sep 2018
Abstract
In this study, we applied a double-sided inductively coupled plasma (ICP) process to nanostructure long-period fiber grating (LPFG) in order to fabricate a double-notched LPFG (DNLPFG) sensor with a double-sided surface corrugated periodic grating. Using the sol-gel method, we also added thymol blue [...] Read more.
In this study, we applied a double-sided inductively coupled plasma (ICP) process to nanostructure long-period fiber grating (LPFG) in order to fabricate a double-notched LPFG (DNLPFG) sensor with a double-sided surface corrugated periodic grating. Using the sol-gel method, we also added thymol blue and ZnO to form a gas sensing layer, thus producing a DNLPFG CO2 gas sensor. The resulting sensor is the first double-sided etching sensor used to measure CO2. The experimental results showed that as the CO2 concentration increased, the transmission loss increased, and that the smaller the fiber diameter, the greater the sensitivity and the greater the change in transmission loss. When the diameter of the fiber was 32 μm (and the period was 570 μm) and the perfusion rate of CO2 gas was 15%, the maximum loss variation of up to 3.881 dB was achieved, while the sensitivity was 0.2146 dB/% and the linearity was 0.992. These results demonstrate that the DNLPG CO2 gas sensor is highly sensitive. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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Open AccessArticle
Humanoid Identification of Fabric Material Properties by Vibration Spectrum Analysis
Sensors 2018, 18(6), 1820; https://doi.org/10.3390/s18061820 - 05 Jun 2018
Abstract
In daily contexts, fabrics embodied in garments are in contact with human body all the time. Since fabric material properties—such as softness or fineness—can be easily sensed by human fingertips, fabric materials can be roughly identified by fingertip sliding. Identification by simply touching [...] Read more.
In daily contexts, fabrics embodied in garments are in contact with human body all the time. Since fabric material properties—such as softness or fineness—can be easily sensed by human fingertips, fabric materials can be roughly identified by fingertip sliding. Identification by simply touching and sliding is convenient and fast, although the room for error is always very large. In this study, a highly discernible fabric humanoid identification method with a fingertip structure inspired tactile sensor is designed to investigate the fabric material properties by characterizing the power spectrum integral of vibration signal basing on fast Fourier transform integral S(FFT), which is generated from a steel ball probe rubbing against a fabric surface at an increasing sliding velocity and normal load, respectively. kv and kw are defined as the slope values to identify the fabric surface roughness and hardness. A sample of 21 pieces of fabric categorized by yarn weight, weave pattern, and material were tested by this method. It was proved that the proposed humanoid sensing method has more efficient compared with fingertip sliding while it is also much more accurate for fabric material identification. Our study would be discussed in light of textile design and has a great number of potential applications in humanoid tactile perception technology. Full article
(This article belongs to the Special Issue I3S 2018 Selected Papers)
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