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Electronics
Volume 11
Issue 7
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Electronics, Volume 11, Issue 7 (April-1 2022) – 194 articles

Cover Story (view full-size image): The design of a thin 2 × 2 CP slot array antenna was presented for a high-band UWB application. The proposed antenna is composed of three parts: a top metal part that consists of an L-shaped slot structure, a dielectric substrate, and a bottom floating metal layer. The prototype antenna size is 29.2 mm × 31.7 mm, and its thickness is 1.636 mm. The measurement results show a maximum gain of 6.94 dBic at 9.02 GHz, whereas that of the 3 dB gain-band was 900 MHz (8.55–9.45 GHz). These results suggest that the proposed CP thin antenna with high gain is qualified to be used in high-band UWB applications. View this paper
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18 pages, 1468 KiB  
Article
Reducing Redundant Test Executions in Software Product Line Testing—A Case Study
by Pilsu Jung, Sungwon Kang and Jihyun Lee
Electronics 2022, 11(7), 1165; https://doi.org/10.3390/electronics11071165 - 6 Apr 2022
Cited by 7 | Viewed by 2519
Abstract
In the context of software product line (SPL) engineering, test cases can be reused for testing a family of products that share common parts of source code. An approach to test the products of a product family is to exhaustively execute each test [...] Read more.
In the context of software product line (SPL) engineering, test cases can be reused for testing a family of products that share common parts of source code. An approach to test the products of a product family is to exhaustively execute each test case on all the products. However, such an approach would be very inefficient because the common parts of source code will be tested multiple times unnecessarily. To reduce unnecessary repetition of testing, we previously proposed a method to avoid equivalent test executions of a product line in the context of regression testing. However, it turns out that the same approach can be used in a broader context than just regression testing of product families. In this paper, we argue the generality of the method in the sense that it can be used for testing of the first version of a product family as well as regression testing of its subsequent versions. In addition, in this paper, in order to make the method practically usable for users, we propose a process for applying it to SPL testing. We demonstrate the generality of our method and the practical applicability of the proposed process for the method by conducting a case study. Full article
(This article belongs to the Section Computer Science & Engineering)
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<p>An illustrative example using the DoorLock SPL. (<b>a</b>) product line code base. (<b>b</b>) test cases.</p> Full article ">Figure 2
<p>The process for avoiding equivalent test executions.</p> Full article ">Figure 3
<p>The feature model for SPL<sub>V0</sub>.</p> Full article ">Figure 4
<p>The feature model for SPL<sub>V1</sub>.</p> Full article ">Figure 5
<p>The feature model for SPL<sub>V2</sub>.</p> Full article ">
18 pages, 4528 KiB  
Article
P-Ride: A Shareability Prediction Based Framework in Ridesharing
by Yu Chen and Liping Wang
Electronics 2022, 11(7), 1164; https://doi.org/10.3390/electronics11071164 - 6 Apr 2022
Cited by 3 | Viewed by 1833
Abstract
Ridesharing services aim to reduce travel costs for users and optimize revenue for drivers and platforms by sharing available seats. Existing works can be roughly classified into two types, i.e., online-based and batch-based methods. The former mainly focuses on responding quickly to the [...] Read more.
Ridesharing services aim to reduce travel costs for users and optimize revenue for drivers and platforms by sharing available seats. Existing works can be roughly classified into two types, i.e., online-based and batch-based methods. The former mainly focuses on responding quickly to the requests, and the latter focuses on meticulously enumerating request combinations to improve service quality. However, online-based methods perform poorly in service quality due to the neglect of the sharing relationship between requests, while batch-based methods fail in terms of efficiency. To obtain better service quality more efficiently, we propose a shareability prediction-based framework P-Ride. Specifically, we first introduce the k-clique listing strategy in graph theory based on the shareability graph to reduce the infeasible request combinations. Moreover, we extend the shareability graph to the hypergraph structure to represent the higher-order shareable relationships among requests. Furthermore, we devise a shareability prediction model that supports the prediction of sharable relationships for request combinations of an arbitrary size, which helps further filtering of candidate request combinations with GPU devices acceleration. The extensive experimental results demonstrate the efficiency and effectiveness of our proposed P-Ride framework. Full article
(This article belongs to the Topic Intelligent Transportation Systems)
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<p>A motivation example.</p> Full article ">Figure 2
<p>The structure of the shareability prediction model based on Hyper-SAGNN [<a href="#B30-electronics-11-01164" class="html-bibr">30</a>].</p> Full article ">Figure 3
<p>P-Ride: Shareability prediction-based ridesharing framework.</p> Full article ">Figure 4
<p>The distribution of the testing requests.</p> Full article ">Figure 5
<p>City borders.</p> Full article ">Figure 6
<p>Performance of variance <math display="inline"><semantics> <mrow> <mo>|</mo> <mi>W</mi> <mo>|</mo> </mrow> </semantics></math>.</p> Full article ">Figure 6 Cont.
<p>Performance of variance <math display="inline"><semantics> <mrow> <mo>|</mo> <mi>W</mi> <mo>|</mo> </mrow> </semantics></math>.</p> Full article ">Figure 7
<p>Performance of variance <math display="inline"><semantics> <mrow> <mo>|</mo> <mi>R</mi> <mo>|</mo> </mrow> </semantics></math>.</p> Full article ">Figure 8
<p>Performance of variance <math display="inline"><semantics> <mi>γ</mi> </semantics></math>.</p> Full article ">Figure 9
<p>Performance of variance <span class="html-italic">c</span>.</p> Full article ">
16 pages, 8219 KiB  
Article
On-Orbit Experimental Result of a Non-Deployable 430-MHz-Band Antenna Using a 1U CubeSat Structure
by Daisuke Nakayama, Takashi Yamauchi, Hirokazu Masui, Sangkyun Kim, Kazuhiro Toyoda, Tharindu Lakmal Dayarathna Malmadayalage, Mengu Cho and the BIRDS-4 Project Team
Electronics 2022, 11(7), 1163; https://doi.org/10.3390/electronics11071163 - 6 Apr 2022
Cited by 4 | Viewed by 2754
Abstract
1U CubeSats often use the 430-MHz band for communication due to their size and power limitations, and half-wavelength dipole antennas are employed. A 430-MHz-band dipole antenna requires a deployable structure for a 1U CubeSat. However, a 1U CubeSat has a small volume margin [...] Read more.
1U CubeSats often use the 430-MHz band for communication due to their size and power limitations, and half-wavelength dipole antennas are employed. A 430-MHz-band dipole antenna requires a deployable structure for a 1U CubeSat. However, a 1U CubeSat has a small volume margin for redundant systems, so the antenna deployment system can be a single point of failure. In this paper, the 1U CubeSat structure itself was used as an antenna. As a sub-mission of the BIRDS-4 project, three 1U CubeSats (GuaraniSat-1, Maya-2, and Tsuru) demonstrated this antenna structure. The results of the ground tests showed a maximum gain of −5.7 dBi with the flight model. These satellites were deployed from the International Space Station on 14 March 2021. Radio signals were alternately transmitted from the dipole antenna and the structure antenna onboard Tsuru for on-orbit demonstration on 15 December 2021, and the received signal strength on the ground was compared using RTL-SDR, SDR# and several codes. The ground station was able to receive both dipole and structure CW signals. The received power strength indicates that a gain of −8.1 dBi is being demonstrated with the structure antenna. Full article
(This article belongs to the Special Issue Antenna Developments for Small Satellites and CubeSats)
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<p>Structure of a Hentenna and Loop Hentenna.</p> Full article ">Figure 2
<p>Flight models of BIRDS-4 satellites. (Left: Maya-2, Center: Tsuru, Right: GuaraniSat-1).</p> Full article ">Figure 3
<p>Overall block diagram of BIRDS-4.</p> Full article ">Figure 4
<p>Order of signal transmission during the HNT mission.</p> Full article ">Figure 5
<p>Loop Hentenna structure and BIRDS-4 main structure.</p> Full article ">Figure 6
<p>BIRDS-4 -X panel: (<b>a</b>) front; (<b>b</b>) back; (<b>c</b>) matching circuit and RF connector.</p> Full article ">Figure 7
<p>Schematic of the matching circuit. Balun: TC-1T+ made by Minicircuits. Inductor: L-15C15NJV4T made by Johanson Technology. Capacitor: 251R14S4R7BV4T made by Johanson Technology.</p> Full article ">Figure 8
<p>Result of return loss measuring: (<b>a</b>) return loss, (<b>b</b>) Smith chart.</p> Full article ">Figure 9
<p>Radiation pattern measurement of the Loop Hentenna mounted on Tsuru (<b>a</b>) YZ plane, (<b>b</b>) ZX plane, (<b>c</b>) XY plane.</p> Full article ">Figure 10
<p>Transmitter for HNT mission.</p> Full article ">Figure 11
<p>Transmitting power. (<b>a</b>) Bus system CW transmitter; (<b>b</b>) HNT mission transmitter (Tsuru).</p> Full article ">Figure 12
<p>Receiving spectrum. (<b>a</b>) Loop Hentenna CW; (<b>b</b>) bus beacon CW.</p> Full article ">Figure 13
<p>Examples of a spectrum generated by FFT. (<b>a</b>) Loop Hentenna CW (T = 26.45 s); (<b>b</b>) bus beacon CW (T = 61.5 s).</p> Full article ">Figure 14
<p>Elapsed seconds and peak intensity since 06:19:40 (UTC) on 15 December 2021.</p> Full article ">Figure 15
<p>Received signal at elapsed time 26 to 30 s.</p> Full article ">Figure 16
<p>Received signal with elapsed time 60.5 to 66.5 s.</p> Full article ">Figure 17
<p>Elapsed seconds and the sight distance from the ground station to Tsuru.</p> Full article ">Figure 18
<p>Elapsed seconds and normalized peak intensity since 06:19:40 (UTC) on 15 December 2021.</p> Full article ">Figure 19
<p>Received signal at elapsed time 16 to 26 s.</p> Full article ">Figure 20
<p>Received signal with elapsed time 56 to 61 s.</p> Full article ">
16 pages, 1175 KiB  
Article
Safety System Assessment Case Study of Automated Vehicle Shuttle
by Heiko Pikner, Raivo Sell, Jüri Majak and Kristo Karjust
Electronics 2022, 11(7), 1162; https://doi.org/10.3390/electronics11071162 - 6 Apr 2022
Cited by 13 | Viewed by 3100
Abstract
Automated vehicle (AV) minibuses, i.e., AV shuttles, are gaining popularity in the testing of new types of transportation services in real traffic conditions. AV shuttles have moved from closed test areas to low-traffic public sites such as local residential areas, technology parks, university [...] Read more.
Automated vehicle (AV) minibuses, i.e., AV shuttles, are gaining popularity in the testing of new types of transportation services in real traffic conditions. AV shuttles have moved from closed test areas to low-traffic public sites such as local residential areas, technology parks, university campuses, etc. These types of vehicles are usually low-speed and rely on a lidar-camera sensor set and a self-driving software stack. These new use cases are increasing these systems’ safety demands. In addition to functional safety, many other aspects need to be considered. In this study, a risk analysis model is developed, combining the fuzzy analytical hierarchy process and the Technique for Order of Preference by Similarity to Ideal Solution method. The proposed model is utilized to prioritize risks corresponding to the particular case study, based on real AV shuttle bus development, and focuses on the low-level hardware/software safety issues and improvements. Full article
(This article belongs to the Special Issue Cyber-Physical Systems in Smart Cities)
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<p>Criteria and risks decision hierarchy.</p> Full article ">Figure 2
<p>Low-level control solution for TalTech iseAuto v2.0.</p> Full article ">Figure 3
<p>Safety triggering logic.</p> Full article ">
11 pages, 399 KiB  
Article
Feasibility Prediction for Rapid IC Design Space Exploration
by Riadul Islam
Electronics 2022, 11(7), 1161; https://doi.org/10.3390/electronics11071161 - 6 Apr 2022
Cited by 4 | Viewed by 2679
Abstract
The DARPA POSH program echoes with the research community and identifies that engineering productivity has fallen behind Moore’s law, resulting in the prohibitive increase in IC design cost at leading technology nodes. The primary reason is that it requires many computing resources, expensive [...] Read more.
The DARPA POSH program echoes with the research community and identifies that engineering productivity has fallen behind Moore’s law, resulting in the prohibitive increase in IC design cost at leading technology nodes. The primary reason is that it requires many computing resources, expensive tools, and even many days to complete a design implementation. However, at the end of this process, some designs could not meet the design constraints and become unroutable, creating a vicious circuit design cycle. As a result, designers have to re-run the whole process after design modification. This research applied a machine learning approach to automatically identify design constraints and design rule checking (DRC) violation issues and help the designer identify design constraints with optimal DRCs before the long detailed routing process through iterative greedy search. The proposed algorithm achieved up to 99.99% design constraint prediction accuracy and reduced 98.4% DRC violations with only a 6.9% area penalty. Full article
(This article belongs to the Section Circuit and Signal Processing)
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<p>A vicious cycle in circuit design often begins with a hardware description of a new design and end-up after sending the tape-out to the fabrication lab by addressing several stressful iterative processes to meet the complex design rules, high-performance, and low area budget.</p> Full article ">Figure 2
<p>The proposed ML-based prediction and IGS methodology integrated with the existing EDA synthesis flow breaks the most expensive vicious cycle path from detailed routing to the behavioral algorithm.</p> Full article ">Figure 3
<p>Illustration of inter-dependency among several constraints of EDA tool flow, varying one constraint while observing the effect on others, (<b>a</b>) performance variation, (<b>b</b>) area variation, (<b>c</b>) DRC variation, and (<b>d</b>) total wire length variation.</p> Full article ">Figure 4
<p>Objective evaluation based on various feature combinations, where the enlarged circle represents the solution for a particular objective.</p> Full article ">
21 pages, 3553 KiB  
Review
A Review on SIW and Its Applications to Microwave Components
by Augustine O. Nwajana and Emenike Raymond Obi
Electronics 2022, 11(7), 1160; https://doi.org/10.3390/electronics11071160 - 6 Apr 2022
Cited by 45 | Viewed by 12627
Abstract
Substrate-integrated waveguide (SIW) is a modern day (21st century) transmission line that has recently been developed. This technology has introduced new possibilities to the design of efficient circuits and components operating in the radio frequency (RF) and microwave frequency spectrum. Microstrip components are [...] Read more.
Substrate-integrated waveguide (SIW) is a modern day (21st century) transmission line that has recently been developed. This technology has introduced new possibilities to the design of efficient circuits and components operating in the radio frequency (RF) and microwave frequency spectrum. Microstrip components are very good for low frequency applications but are ineffective at extreme frequencies, and involve rigorous fabrication concessions in the implementation of RF, microwave, and millimeter-wave components. This is due to wavelengths being short at higher frequencies. Waveguide devices, on the other hand, are ideal for higher frequency systems, but are very costly, hard to fabricate, and challenging to integrate with planar components in the neighborhood. SIW connects the gap that existed between conventional air-filled rectangular waveguide and planar transmission line technologies including the microstrip. This study explores the current advancements and new opportunities in SIW implementation of RF and microwave devices including filters, multiplexers (diplexers and triplexers), power dividers/combiners, antennas, and sensors for modern communication systems. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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<p>SIW structure development. (<b>a</b>) Air-filled rectangular waveguide. (<b>b</b>) Dielectric-filled rectangular waveguide. (<b>c</b>) Substrate-integrated waveguide.</p> Full article ">Figure 2
<p>The <span class="html-italic">TE</span><sub>1,0</sub> mode surface current distribution of a conventional rectangular waveguide with metallic holes on the thin side walls.</p> Full article ">Figure 3
<p>Physical structure of the substrate-integrated waveguide transmission line.</p> Full article ">Figure 4
<p>Substrate-integrated waveguide fundamental design parameters.</p> Full article ">Figure 5
<p>Some popular transitions between planar transmission lines and substrate-integrated waveguides: (<b>a</b>) microstrip-to-SIW transition based on a simple taper; (<b>b</b>) CPW-to-SIW transition based on a current probe; (<b>c</b>) CPW-to-SIW transition based on a ninety-degree bend [<a href="#B14-electronics-11-01160" class="html-bibr">14</a>].</p> Full article ">Figure 6
<p>Cross section of the different versions of the compact SIW structures: (<b>a</b>) substrate-integrated folded waveguide; (<b>b</b>) half-mode substrate-integrated waveguide; (<b>c</b>) substrate-integrated ridge waveguide; (<b>d</b>) substrate-integrated slab waveguide [<a href="#B14-electronics-11-01160" class="html-bibr">14</a>].</p> Full article ">Figure 7
<p>Simulation and measurement responses of a conventional three-pole SIW filter including the image of the fabricated filter device.</p> Full article ">Figure 8
<p>Simulation and measurement responses and the image of the fabricated SIW filters: (<b>a</b>) four-pole half-mode SIW bandpass filter. Reprinted/adapted with permission from Ref. [<a href="#B49-electronics-11-01160" class="html-bibr">49</a>]. 2021, F. Zhu et al.; (<b>b</b>) third-order triple-band bandpass filter [<a href="#B72-electronics-11-01160" class="html-bibr">72</a>].</p> Full article ">Figure 8 Cont.
<p>Simulation and measurement responses and the image of the fabricated SIW filters: (<b>a</b>) four-pole half-mode SIW bandpass filter. Reprinted/adapted with permission from Ref. [<a href="#B49-electronics-11-01160" class="html-bibr">49</a>]. 2021, F. Zhu et al.; (<b>b</b>) third-order triple-band bandpass filter [<a href="#B72-electronics-11-01160" class="html-bibr">72</a>].</p> Full article ">Figure 9
<p>Simulation and measurement responses of a tuneable SIW diplexer including the images of the fabricated filter component. Reprinted/adapted with permission from Ref. [<a href="#B77-electronics-11-01160" class="html-bibr">77</a>]. 2019, A. Iqbal et al.</p> Full article ">Figure 10
<p>Simulation and measurement responses and images of the fabricated SIW filtering power divider: (<b>a</b>) with equal power division; (<b>b</b>) with unequal power division. Reprinted/adapted with permission from Ref. [<a href="#B82-electronics-11-01160" class="html-bibr">82</a>]. 2020, G. Zhang et al.</p> Full article ">Figure 11
<p>Image, simulation, and measurement responses of a filtering antenna [<a href="#B84-electronics-11-01160" class="html-bibr">84</a>].</p> Full article ">Figure 12
<p>Image and experimental resonant curves for sensor A using various samples. Reprinted/adapted with permission from Ref. [<a href="#B102-electronics-11-01160" class="html-bibr">102</a>]. 2019, H.L. Morales.</p> Full article ">
13 pages, 16357 KiB  
Article
Fuzzy Compensation and Load Disturbance Adaptive Control Strategy for Electro-Hydraulic Servo Pump Control System
by Yu Song, Zhongwang Hu and Chao Ai
Electronics 2022, 11(7), 1159; https://doi.org/10.3390/electronics11071159 - 6 Apr 2022
Cited by 10 | Viewed by 2494
Abstract
Aiming at the high-precision position control of electro-hydraulic servo pump control system, a compensation control algorithm based on fuzzy control theory is proposed based on the classical PID control algorithm for the control of factors such as oil compression and system leakage. Firstly, [...] Read more.
Aiming at the high-precision position control of electro-hydraulic servo pump control system, a compensation control algorithm based on fuzzy control theory is proposed based on the classical PID control algorithm for the control of factors such as oil compression and system leakage. Firstly, a mathematical model of the system was established, and online identification of load disturbance was carried out. Then, oil compression and system leakage compensation controllers were established, and the position error caused by the load disturbance was compensated based on fuzzy control rules. Finally, the position control effect was verified using an experimental platform. The results show that the load disturbance compensation control strategy can significantly reduce the influence of load disturbance of the system. The steady-state accuracy of the system reached ±0.01 mm, which significantly enhanced the anti-disturbance ability of the system. Full article
(This article belongs to the Topic Advanced Systems Engineering: Theory and Applications)
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<p>Hydraulic system diagram of electro-hydraulic servo pump control system: 1—servo motor; 2—quantitative pump; 3—hydraulic oil tank; 4—check valves; 5—relief valves; 6—hydraulic cylinder.</p> Full article ">Figure 2
<p>System control schematic diagram.</p> Full article ">Figure 3
<p>Fuzzy controller design steps.</p> Full article ">Figure 4
<p>Triangle type membership function diagram. Since the load force, change rate of the load force, and the output speed of electro-hydraulic servo pump control system are accurate quantities, and the control parameters in the fuzzy controller are fuzzy quantities, the range of variables [a, b] needs to be transformed into the domain [−6, 6], and each interval corresponds to different fuzzy sets. In this system, the range of load force is below 12 KN, and the domain of load force input variable is [−6, 6], so the quantization factor of load force input is 0.001; the range of load force change rate is [−60, 60], and the domain of input variable of load force change rate is [−6, 6], so the quantization factor of input quantity of load force change rate is 0.1; the range of output speed is [−300, 300], and the domain of output speed variable is [−6, 6], so the scale factor of output speed variable is 50.</p> Full article ">Figure 5
<p>Hydraulic part of experimental platform.</p> Full article ">Figure 6
<p>Electrical part of experimental platform.</p> Full article ">Figure 7
<p>Software part of experimental platform.</p> Full article ">Figure 8
<p>Response curve of the extended position of the hydraulic cylinder.</p> Full article ">Figure 9
<p>Local magnification curve of the extended position of the hydraulic cylinder.</p> Full article ">Figure 10
<p>Speed response curve of the servo motor.</p> Full article ">Figure 11
<p>Response curve of the retracted position of the hydraulic cylinder.</p> Full article ">Figure 12
<p>Local magnification curve of the retracted position of the hydraulic cylinder.</p> Full article ">Figure 13
<p>Speed response curve of the servo motor.</p> Full article ">
23 pages, 10522 KiB  
Review
Research and Application of Capacitive Power Transfer System: A Review
by Zhulin Wang, Yiming Zhang, Xinghong He, Bo Luo and Ruikun Mai
Electronics 2022, 11(7), 1158; https://doi.org/10.3390/electronics11071158 - 6 Apr 2022
Cited by 27 | Viewed by 11076
Abstract
Capacitive power transfer (CPT) uses an electric field as the transfer medium to achieve wireless power transfer (WPT). Benefitting from the low eddy current loss, simple system structure and strong plasticity of the coupling coupler, the CPT system has recently gained much attention. [...] Read more.
Capacitive power transfer (CPT) uses an electric field as the transfer medium to achieve wireless power transfer (WPT). Benefitting from the low eddy current loss, simple system structure and strong plasticity of the coupling coupler, the CPT system has recently gained much attention. The CPT system has significantly improved transfer power, system efficiency, and transfer distance due to continuous research and discussion worldwide. This review briefly presents the basic working principle of the CPT system and summarizes the theoretical research in four aspects, including coupling coupler and high-frequency power converter. Following this, the review focuses on research in six key directions, including system modelling and efficiency optimization. The application of CPT technology in five fields, including medical devices and transportation, is also discussed. This review introduces the progress of CPT research in recent years, hoping to serve as a reference for researchers, to promote the further research and application of the CPT system. Full article
(This article belongs to the Collection Wireless Power Transfer: Material, Technologies, and Applications)
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<p>General CPT circuit with a simplified coupling coupler.</p> Full article ">Figure 2
<p>Structure diagram of CPT system.</p> Full article ">Figure 3
<p>Coupler model by two capacitors connected in series.</p> Full article ">Figure 4
<p>Different forms of CPT system coupler: (<b>a</b>) Parallel disc-shaped, annular coupling mechanism. Reprinted with permission from ref. [<a href="#B25-electronics-11-01158" class="html-bibr">25</a>], 2020 IEEE. (<b>b</b>) Parallel cylindrical coupling mechanism. Reprinted with permission from ref. [<a href="#B28-electronics-11-01158" class="html-bibr">28</a>]. (<b>c</b>) Laminated rectangular coupling mechanism. Reprinted with permission from ref. [<a href="#B29-electronics-11-01158" class="html-bibr">29</a>], 2019 IEEE. (<b>d</b>) Array type rectangular coupling mechanism. Reprinted with permission from ref. [<a href="#B30-electronics-11-01158" class="html-bibr">30</a>], 2019 IEEE.</p> Full article ">Figure 5
<p>Equivalent circuit model for the typically four-plates coupler: (<b>a</b>) typical four-plate coupler, (<b>b</b>) full capacitor model, (<b>c</b>) π-model.</p> Full article ">Figure 6
<p>Schematic diagram of single capacitor CPT system. Reprinted from ref. [<a href="#B85-electronics-11-01158" class="html-bibr">85</a>].</p> Full article ">Figure 7
<p>System coupler with shielding plates and simulated electric field distribution. Reprinted with permission from ref. [<a href="#B22-electronics-11-01158" class="html-bibr">22</a>], 2018 IEEE: (<b>a</b>) coupler dimension; (<b>b</b>) simulated electric field distribution.</p> Full article ">Figure 8
<p>Power supply for biomedical implants based on CPT system. Reprinted with permission from ref. [<a href="#B107-electronics-11-01158" class="html-bibr">107</a>], 2016 IEEE: (<b>a</b>) coupling model, (<b>b</b>) experiment.</p> Full article ">Figure 9
<p>Schematic diagram of EV charging based on the CPT system by using concrete pavement and tire steel belt. Reprinted with permission from ref. [<a href="#B111-electronics-11-01158" class="html-bibr">111</a>], 2013 IEEE.</p> Full article ">Figure 10
<p>Energy harvesting based on CPT system using power line insulators. Reprinted with permission from ref. [<a href="#B118-electronics-11-01158" class="html-bibr">118</a>], 2014 IEEE.</p> Full article ">Figure 11
<p>Schematic diagram of system coupling coupler and underwater test. Reprinted from ref. [<a href="#B124-electronics-11-01158" class="html-bibr">124</a>].</p> Full article ">Figure 12
<p>Pneumatic fluid bearing experimental device and circuit structure diagram. Reprinted with permission from ref. [<a href="#B126-electronics-11-01158" class="html-bibr">126</a>], 2014 IEEE.</p> Full article ">
17 pages, 6358 KiB  
Article
Smart Cities and Awareness of Sustainable Communities Related to Demand Response Programs: Data Processing with First-Order and Hierarchical Confirmatory Factor Analyses
by Simona-Vasilica Oprea, Adela Bâra, Cristian-Eugen Ciurea and Laura Florentina Stoica
Electronics 2022, 11(7), 1157; https://doi.org/10.3390/electronics11071157 - 6 Apr 2022
Cited by 5 | Viewed by 2958
Abstract
The mentality of electricity consumers is one of the most important entities that must be addressed when dealing with issues in the operation of power systems. Consumers are used to being completely passive, but recently these things have changed as significant progress of [...] Read more.
The mentality of electricity consumers is one of the most important entities that must be addressed when dealing with issues in the operation of power systems. Consumers are used to being completely passive, but recently these things have changed as significant progress of Information and Communication Technologies (ICT) and Internet of Things (IoT) has gained momentum. In this paper, we propose a statistical measurement model using a covariance structure, specifically a first-order confirmatory factor analysis (CFA) using SAS CALIS procedure to identify the factors that could contribute to the change of attitude within energy communities. Furthermore, this research identifies latent constructs and indicates which observed variables load on or measure them. For the simulation, two complex data sets of questionnaires created by the Irish Commission for Energy Regulation (CER) were analyzed, demonstrating the influence of some exogenous variables on the items of the questionnaires. The results revealed that there is a relevant relationship between the social–economic and the behavioral factors and the observed variables. Furthermore, the models provided a good fit to the data, as measured by the performance indicators. Full article
(This article belongs to the Special Issue Advances in Machine Learning, IoT and Big Data for Sustainable Communities)
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<p>Research methodology.</p> Full article ">Figure 2
<p>Scatter plot and distribution of variables (<b>a</b>) q1–q5, (<b>b</b>) q3–q7 of the pre-trial data set.</p> Full article ">Figure 3
<p>Scatter plot and distribution of variables (<b>a</b>) q1–q5, (<b>b</b>) q6–q9 of the post-trial data set.</p> Full article ">Figure 4
<p>Outliers (<b>a</b>) pre-trial data set and (<b>b</b>) post-trial data set.</p> Full article ">Figure 5
<p>Q-Q plot of residuals (<b>a</b>) pre-trial data set and (<b>b</b>) post-trial data set.</p> Full article ">Figure 6
<p>P-P plot of residuals (<b>a</b>) pre-trial data set, (<b>b</b>) post-trial data set.</p> Full article ">Figure 7
<p>Distribution of residuals (<b>a</b>) pre-trial data set, (<b>b</b>) post-trial data set.</p> Full article ">Figure 8
<p>Path diagrams for the data set of the pre-trial questionnaire (<b>a</b>) initial (<b>b</b>) after modification.</p> Full article ">Figure 9
<p>Path diagrams for the post-trial questionnaire data set (<b>a</b>) initial (<b>b</b>) after modification.</p> Full article ">Figure 10
<p>Path diagrams for the pre-trial questionnaire data set (<b>a</b>) second-order, (<b>b</b>) bi-factor.</p> Full article ">Figure 11
<p>Path diagrams for the post-trial questionnaire data set (<b>a</b>) second-order, (<b>b</b>) bi-factor.</p> Full article ">
14 pages, 5676 KiB  
Article
Design of a Low-Profile Wideband Magnetoelectric Dipole Antenna with Reduced Gain Drop
by Zhiyi Li, Xing Chen, Yuzhu Tang, Liangbing Liao, Linwan Deng and Zhifan Zhao
Electronics 2022, 11(7), 1156; https://doi.org/10.3390/electronics11071156 - 6 Apr 2022
Cited by 2 | Viewed by 2869
Abstract
In this paper, a novel low-profile magnetoelectric (ME) dipole antenna with wideband is presented. The conventional vertical fixing structure is bended four times from the center to the sides. The Γ-shaped feeding structure is bended two times to lower the height of the [...] Read more.
In this paper, a novel low-profile magnetoelectric (ME) dipole antenna with wideband is presented. The conventional vertical fixing structure is bended four times from the center to the sides. The Γ-shaped feeding structure is bended two times to lower the height of the antenna step by step. The effect of three kinds of vertical wall is discussed to show their influence on boresight gain. Through comparison, only one vertical wall is erected on the left side of the ground to decrease the boresight gain drop at 2.2 GHz. Both simulation and analysis are made to sufficiently explain the working principle. At last, the proposed ME dipole antenna has only 0.095λ0 (λ0 is the center operating wavelength in free space) in height, and the wideband property is still maintained. By simulation, the relative bandwidth for VSWR < 2.0 is 47.9% (from 1.35 to 2.2 GHz). The boresight gain ranges from 8.1 to 9.6 dBi in the operating band. The measured relative bandwidth for VSWR < 2.0 is 50.3% (from 1.34 to 2.24 GHz), and the boresight gain ranges from 7.38 to 8.73 dBi. The gain drop on boresight is less than 1.4 dBi. Radiation patterns show a unidirectional characteristic in the whole operating band. Additionally, the cross-polarization level is less than −25 dB on boresight. The simulating and measuring results agree well with each other. Therefore, the proposed antenna is suitable for applications of limited height and wideband. Full article
(This article belongs to the Topic Antennas)
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<p>A depiction of the current low-profile techniques for an ME dipole antenna. (<b>a</b>) antenna 1; (<b>b</b>) antenna 2; (<b>c</b>) antenna 3; (<b>d</b>) antenna 4.</p> Full article ">Figure 2
<p>The evolution of the proposed low-profile ME dipole.</p> Full article ">Figure 3
<p>The structure of the proposed low-profile ME dipole. (<b>a</b>) Front view, (<b>b</b>) top view, (<b>c</b>) bended fixing structure, (<b>d</b>) feeding line.</p> Full article ">Figure 3 Cont.
<p>The structure of the proposed low-profile ME dipole. (<b>a</b>) Front view, (<b>b</b>) top view, (<b>c</b>) bended fixing structure, (<b>d</b>) feeding line.</p> Full article ">Figure 4
<p>The schematic diagram of electric dipole and magnetic dipole.</p> Full article ">Figure 5
<p>(<b>a</b>) The structure of ANT 1, ANT 2, and ANT3; (<b>b</b>) VSWR of ANT 1, ANT 2, and ANT3; (<b>c</b>) impedance of ANT 1, ANT 2, and ANT 3.</p> Full article ">Figure 5 Cont.
<p>(<b>a</b>) The structure of ANT 1, ANT 2, and ANT3; (<b>b</b>) VSWR of ANT 1, ANT 2, and ANT3; (<b>c</b>) impedance of ANT 1, ANT 2, and ANT 3.</p> Full article ">Figure 6
<p>The structure of the antenna with (<b>a</b>) two symmetric vertical walls; (<b>b</b>) only flat ground plane; (<b>c</b>) one vertical wall; (<b>d</b>) the VSWR for different ground; (<b>e</b>) the radiating E field at 2.2 GHz for antenna 1; (<b>f</b>) the radiating E field at 2.2 GHz for the antenna with the single vertical wall on the left side; (<b>g</b>) the radiating E field at 2.2 GHz for antenna 3.</p> Full article ">Figure 6 Cont.
<p>The structure of the antenna with (<b>a</b>) two symmetric vertical walls; (<b>b</b>) only flat ground plane; (<b>c</b>) one vertical wall; (<b>d</b>) the VSWR for different ground; (<b>e</b>) the radiating E field at 2.2 GHz for antenna 1; (<b>f</b>) the radiating E field at 2.2 GHz for the antenna with the single vertical wall on the left side; (<b>g</b>) the radiating E field at 2.2 GHz for antenna 3.</p> Full article ">Figure 7
<p>The distribution of electric current in one period. (<b>a</b>) at t = 0, (<b>b</b>) at t = T/4, (<b>c</b>) at t = T/2, (<b>d</b>) at t = 3T/4.</p> Full article ">Figure 7 Cont.
<p>The distribution of electric current in one period. (<b>a</b>) at t = 0, (<b>b</b>) at t = T/4, (<b>c</b>) at t = T/2, (<b>d</b>) at t = 3T/4.</p> Full article ">Figure 8
<p>The parameter analysis for (<b>a</b>) W3, (<b>b</b>) L2, (<b>c</b>) a, and (<b>d</b>) b.</p> Full article ">Figure 8 Cont.
<p>The parameter analysis for (<b>a</b>) W3, (<b>b</b>) L2, (<b>c</b>) a, and (<b>d</b>) b.</p> Full article ">Figure 9
<p>The measurement of proposed antenna.</p> Full article ">Figure 10
<p>The comparison of simulated VSWR and boresight gain.</p> Full article ">Figure 11
<p>The simulated and measured radiation patterns at (<b>a</b>) 1.4 GHz, (<b>b</b>) 1.8 GHz, (<b>c</b>) 2.2 GHz.</p> Full article ">
31 pages, 992 KiB  
Review
Communication Technologies in Emergency Situations
by Anna Carreras-Coch, Joan Navarro, Carles Sans and Agustín Zaballos
Electronics 2022, 11(7), 1155; https://doi.org/10.3390/electronics11071155 - 6 Apr 2022
Cited by 16 | Viewed by 9031
Abstract
Emergency situations such as wildfires, water floods, or even terrorist attacks require continuous communication between the coordination centres, the several on-the-field teams, and their respective devices to properly address the adverse circumstances. From a technological point of view, this can be best seen [...] Read more.
Emergency situations such as wildfires, water floods, or even terrorist attacks require continuous communication between the coordination centres, the several on-the-field teams, and their respective devices to properly address the adverse circumstances. From a technological point of view, this can be best seen as a live Ubiquitous Sensor Network—composed of human beings (e.g., first responders, victims) and devices (e.g., drones, environmental sensors, radios)—with stringent and special communication requirements in terms of flexibility, mobility, reliability, bandwidth, heterogeneity, and speed of deployment. However, for this specific use case, most of the already deployed and well-known communication technologies (e.g., satellite, 4G/5G) might become unusable and hard to repair due to the associated effects of the disaster itself. The purpose of this paper is (1) to review the emergency communications challenges, (2) to analyse the existing surveys on technologies for emergency situations, (3) to conduct a more updated, extensive, and systematic review of the emergency communications’ technologies, and (4) to propose a heterogeneous communication architecture able to communicate between moving agents in harsh conditions. The proposed approach is conceived to link the relocating agents that constitute a Ubiquitous Sensor Network spanning a large-scale area (i.e., hundreds of square kilometres) by combining Near Vertical Incidence Skywave technologies with Drone-Based Wireless Mesh Networks. The conclusions derived from this research aim to set up the fundamentals of a rapidly deployable Emergency Communications System inspired by the Ubiquitous Sensor Network paradigm. Full article
(This article belongs to the Special Issue Ubiquitous Sensor Networks)
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<p>System review flow chart.</p> Full article ">Figure 2
<p>Possible communications technology stack for emergency communications system.</p> Full article ">
12 pages, 580 KiB  
Article
Integrated Equipment for Parkinson’s Disease Early Detection Using Graph Convolution Network
by Yefei He, Tao Yang, Cheng Yang and Hong Zhou
Electronics 2022, 11(7), 1154; https://doi.org/10.3390/electronics11071154 - 6 Apr 2022
Cited by 4 | Viewed by 3280
Abstract
There is an increasing need to diagnose Parkinson’s disease (PD) in an early stage. Existing solutions mainly focused on traditional ways such as MRI, thus suffering from the ease-of-use issue. This work presents a new approach using video and skeleton-based techniques to solve [...] Read more.
There is an increasing need to diagnose Parkinson’s disease (PD) in an early stage. Existing solutions mainly focused on traditional ways such as MRI, thus suffering from the ease-of-use issue. This work presents a new approach using video and skeleton-based techniques to solve this problem. In this paper, an end-to-end Parkinson’s disease early diagnosis method based on graph convolution networks is proposed, which takes patients’ skeletons sequence as input and returns the diagnosis result. The asymmetric dual-branch network architecture is designed to process global and local information separately and capture the subtle manifestation of PD. To train the network, we present the first Parkinson’s disease gait dataset, PD-Walk. This dataset consists of 95 PD patients and 96 healthy people’s walking videos. All the data are annotated by experienced doctors. Furthermore, we implement our method on portable equipment, which has been in operation in the First Affiliated Hospital, Zhejiang University School of Medicine. Experiments show that our method can achieve 84.1% accuracy and achieve real-time performance on the equipment in the real environment. Compared with traditional solutions, the proposed method can detect suspicious PD symptoms quickly and conveniently. Integrated equipment can be easily placed in hospitals or nursing homes to provide services for elderly people. Full article
(This article belongs to the Topic Applied System on Biomedical Engineering, Healthcare and Sustainability)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>The overall process of data collection and preprocessing. All the videos captured in process (<b>a</b>) are then cut into the same length in (<b>b</b>). In process of (<b>c</b>), HRNet was used to extract human skeletons. (<b>d</b>) shows the process of skeleton alignment.</p> Full article ">Figure 2
<p>A visualization of samples in PD-Walk dataset.</p> Full article ">Figure 3
<p>The dual branch network structure. The upper branch uses a local connection with input trajectory and velocity, while the lower branch uses a global connection with input velocity and acceleration.</p> Full article ">Figure 4
<p>Joint connections (with head removed). (<b>a</b>) Local connections, (<b>b</b>) global connections.</p> Full article ">Figure 5
<p>The equipment structure. An additional development board is used to expand the necessary interface. All devices are integrated in a chassis.</p> Full article ">Figure 6
<p>Performance comparison between Atlas200DK and RTX2080Ti (running ADGCN only).</p> Full article ">
17 pages, 1655 KiB  
Article
A Cascade Framework for Privacy-Preserving Point-of-Interest Recommender System
by Longyin Cui and Xiwei Wang
Electronics 2022, 11(7), 1153; https://doi.org/10.3390/electronics11071153 - 6 Apr 2022
Cited by 3 | Viewed by 2215
Abstract
Point-of-interest (POI) recommender systems (RSes) have gained significant popularity in recent years due to the prosperity of location-based social networks (LBSN). However, in the interest of personalization services, various sensitive contextual information is collected, causing potential privacy concerns. This paper proposes a cascaded [...] Read more.
Point-of-interest (POI) recommender systems (RSes) have gained significant popularity in recent years due to the prosperity of location-based social networks (LBSN). However, in the interest of personalization services, various sensitive contextual information is collected, causing potential privacy concerns. This paper proposes a cascaded privacy-preserving POI recommendation (CRS) framework that protects contextual information such as user comments and locations. We demonstrate a minimized trade-off between the privacy-preserving feature and prediction accuracy by applying a semi-decentralized model to real-world datasets. Full article
(This article belongs to the Special Issue Recommender Systems: Approaches, Challenges and Applications)
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<p>The framework of a traditional centralized POI recommender system above an LBSN. The users’ private information is collected by location-based social networks and aggregated in the central server.</p> Full article ">Figure 2
<p>The overall model structure and the tasks of each component as well as the data flow.</p> Full article ">Figure 3
<p>The user rating distribution (Phoenix). The <span class="html-italic">X</span> axis represents the numerical user IDs starting from 1. For example, if we have 10 users, they will be numbered from 1 to 10. The <span class="html-italic">Y</span> axis is the number of ratings they have left and it is on log scale to show a clearer distribution.</p> Full article ">Figure 4
<p>The user visiting locations (Phoenix). Each point represents a user visiting a real-world geographical location. (Abscissa: the latitude; Ordinate: the longitude).</p> Full article ">Figure 5
<p>The RMSE comparisons among the four models for each training–test dataset pair (Champaign-Urbana). The dataset is partitioned chronologically. (Abscissa: value of RMSE; ordinate: index of folds).</p> Full article ">Figure 6
<p>The MAE comparisons among the four models for each training–test dataset pair (Champaign-Urbana). The dataset is partitioned chronologically. (Abscissa: value of MAE; Ordinate: index of folds).</p> Full article ">Figure 7
<p>The RMSE comparisons among the four models for each training–test dataset pair (City of Phoenix). The dataset is partitioned chronologically. (Abscissa: value of RMSE; ordinate: index of folds).</p> Full article ">Figure 8
<p>The MAE comparisons among the four models for each training–test dataset pair (City of Phoenix). The dataset is partitioned chronologically. (Abscissa: value of MAE; ordinate: index of folds).</p> Full article ">Figure 9
<p>The impact on the average RMSE value from changes on <math display="inline"><semantics> <msup> <mi>α</mi> <mo>′</mo> </msup> </semantics></math> in Equation (<a href="#FD9-electronics-11-01153" class="html-disp-formula">9</a>) (Champaign-Urbana). The <math display="inline"><semantics> <msup> <mi>α</mi> <mo>′</mo> </msup> </semantics></math> indicates the weight of geographical similarities among the users played in the affinity matrix <span class="html-italic">S</span>.</p> Full article ">
17 pages, 751 KiB  
Article
M-Emu: A Platform for Multicast Emulation
by Zhenyu Tian, Jiali You and Hong Ni
Electronics 2022, 11(7), 1152; https://doi.org/10.3390/electronics11071152 - 6 Apr 2022
Viewed by 2151
Abstract
Network layer multicast research is an important field of network research that requires simulators or emulators to support Software-Defined Networking (SDN) as well as to provide a specific structure at the network layer to facilitate packet forwarding, such as a multicast tree. The [...] Read more.
Network layer multicast research is an important field of network research that requires simulators or emulators to support Software-Defined Networking (SDN) as well as to provide a specific structure at the network layer to facilitate packet forwarding, such as a multicast tree. The existing emulation platforms cannot effectively support the emulation of certain key multicast technologies, such as the Grafting Point (GP)-selection method and Rendezvous Point (RP)-selection method, for the following reasons: First, the programmable data plane of the existing emulation platform has many defects, such as the inability to process packet scheduling tasks, the prohibition of dynamic memory allocation and loops with unknown iteration counts, which make it difficult to deploy complex multicast protocols and algorithms. Secondly, at present, no emulation platform integrates network layer multicast emulation functions. As a result, users need to develop the multicast tree construction and maintenance mechanism in advance, which makes experiments laborious. To solve the above problems, based on NS4, we designed a multicast emulation platform, M-Emu. M-Emu presents a Service-Forwarding Architecture, which enables the data plane to deploy arbitrary complex protocols and algorithms. Based on the Service-Forwarding Architecture, M-Emu integrates a Multicast-Emulation Framework, which has a complete multicast tree construction and maintenance mechanism. We explain in detail how the various parts of M-Emu cooperate to complete the multicast emulation with an example and prove that M-Emu is efficient in CPU and memory consumption, etc., through a large number of experiments. Full article
(This article belongs to the Section Computer Science & Engineering)
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<p>Service-forwarding architecture.</p> Full article ">Figure 2
<p>Multicast-Emulation Framework.</p> Full article ">Figure 3
<p>The packet information format.</p> Full article ">Figure 4
<p>PIM-SM Emulation.</p> Full article ">Figure 5
<p>The process of emulation of PIM-SM.</p> Full article ">Figure 6
<p>Packet-Information 1.</p> Full article ">Figure 7
<p>Packet-Information 2.</p> Full article ">Figure 8
<p>Packet-Information 3.</p> Full article ">Figure 9
<p>Memory consumption.</p> Full article ">Figure 10
<p>CPU utilization.</p> Full article ">Figure 11
<p>Traffic of the management message.</p> Full article ">Figure 12
<p>Packet process time.</p> Full article ">Figure 13
<p>Execution time.</p> Full article ">
15 pages, 989 KiB  
Article
Human Detection in Aerial Thermal Images Using Faster R-CNN and SSD Algorithms
by K. R. Akshatha, A. Kotegar Karunakar, Satish B. Shenoy, Abhilash K. Pai, Nikhil Hunjanal Nagaraj and Sambhav Singh Rohatgi
Electronics 2022, 11(7), 1151; https://doi.org/10.3390/electronics11071151 - 6 Apr 2022
Cited by 41 | Viewed by 6980
Abstract
The automatic detection of humans in aerial thermal imagery plays a significant role in various real-time applications, such as surveillance, search and rescue and border monitoring. Small target size, low resolution, occlusion, pose, and scale variations are the significant challenges in aerial thermal [...] Read more.
The automatic detection of humans in aerial thermal imagery plays a significant role in various real-time applications, such as surveillance, search and rescue and border monitoring. Small target size, low resolution, occlusion, pose, and scale variations are the significant challenges in aerial thermal images that cause poor performance for various state-of-the-art object detection algorithms. Though many deep-learning-based object detection algorithms have shown impressive performance for generic object detection tasks, their ability to detect smaller objects in the aerial thermal images is analyzed through this study. This work carried out the performance evaluation of Faster R-CNN and single-shot multi-box detector (SSD) algorithms with different backbone networks to detect human targets in aerial view thermal images. For this purpose, two standard aerial thermal datasets having human objects of varying scale are considered with different backbone networks, such as ResNet50, Inception-v2, and MobileNet-v1. The evaluation results demonstrate that the Faster R-CNN model trained with the ResNet50 network architecture out-performed in terms of detection accuracy, with a mean average precision (mAP at 0.5 IoU) of 100% and 55.7% for the test data of the OSU thermal dataset and AAU PD T datasets, respectively. SSD with MobileNet-v1 achieved the highest detection speed of 44 frames per second (FPS) on the NVIDIA GeForce GTX 1080 GPU. Fine-tuning the anchor parameters of the Faster R-CNN ResNet50 and SSD Inception-v2 algorithms caused remarkable improvement in mAP by 10% and 3.5%, respectively, for the challenging AAU PD T dataset. The experimental results demonstrated the application of Faster R-CNN and SSD algorithms for human detection in aerial view thermal images, and the impact of varying backbone network and anchor parameters on the performance improvement of these algorithms. Full article
(This article belongs to the Special Issue Machine Learning and Photonics Cooperation: Principles, Algorithms, and Systems)
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<p>Sample thermal images from (<b>a</b>,<b>b</b>) OSU thermal dataset and (<b>c</b>–<b>f</b>) AAU PD T dataset.</p> Full article ">Figure 2
<p>Proposed approach to compare various deep learning-based human detection models. Note: FRCNN stands for Faster R-CNN.</p> Full article ">Figure 3
<p>Faster R-CNN approach for object detection.</p> Full article ">Figure 4
<p>SSD approach for object detection.</p> Full article ">Figure 5
<p>Sample annotated images from (<b>a</b>) OSU dataset (<b>b</b>) AAU PD T dataset.</p> Full article ">Figure 6
<p>Precision–recall curve comparison of various models for validation set. Note: Faster RCNN-IV2 stands for Faster R-CNN with Inception V2, SSD-IV2 stands for SSD with Inception-V2.</p> Full article ">Figure 7
<p>Performance comparison between original faster R-CNN ResNet50 model and its modified version on validation dataset.</p> Full article ">Figure 8
<p>Qualitative results of various models (<b>a</b>) ground truth (<b>b</b>–<b>e</b>) predictions.</p> Full article ">
15 pages, 1815 KiB  
Article
Secrecy Enhancement for SSK-Based Visible Light Communication Systems
by Wangzhaoqi Xie, Bao Li, Yuyang Peng, Han Zhu, Fawaz AL-Hazemi and Mohammad Meraj Mirza
Electronics 2022, 11(7), 1150; https://doi.org/10.3390/electronics11071150 - 6 Apr 2022
Cited by 3 | Viewed by 2077
Abstract
Visible light communication (VLC) is a technology that uses unlicensed light spectrum resources and high spatial reuse rates for communication. Because it does not occupy any resource allocation in wireless communication, it has fully alleviated the problem of spectrum scarcity in radio frequency [...] Read more.
Visible light communication (VLC) is a technology that uses unlicensed light spectrum resources and high spatial reuse rates for communication. Because it does not occupy any resource allocation in wireless communication, it has fully alleviated the problem of spectrum scarcity in radio frequency (RF) communication and gradually become a new development direction. However, owing to the inherent broadcasting nature of the VLC channel, the VLC link is vulnerable to eavesdropping by unexpected or unauthorized users in spacious public places. Therefore, enhancing the security of the VLC system has attracted extensive attention. This paper studies the security optimization scheme of the VLC system based on the space shift keying (SSK) technology in the free space optical environment called the SSK-VLC system. The antenna selection (AS) technology and artificial noise (AN) cancellation method are adopted to enhance the confidentiality of the SSK-VLC system. In this paper, we presume that the SSK-VLC system includes three parts: a transmitter containing multiple light-emitting diodes, a legitimate receiver, and an eavesdropper, respectively. By using the designed AS and AN method, the transmitted valid information can be demodulated at the legitimate receiver, and at the same time, the received information by the eavesdropper will be disturbed. The simulation results prove that the proposed optimization scheme can further improve the security performance, including the secrecy rate (SR) and the bit error ratio (BER), compared with the traditional SSK-VLC scheme. Full article
(This article belongs to the Special Issue MIMO: Multiple Input Multiple Output Technology for Physical-Layer Security)
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<p>System model of SSK-VLC channel.</p> Full article ">Figure 2
<p>SR over SNR under different schemes for different <math display="inline"><semantics> <mi>v</mi> </semantics></math>.</p> Full article ">Figure 3
<p>SR over SNR under different schemes for different <math display="inline"><semantics> <mrow> <msub> <mi>N</mi> <mi>a</mi> </msub> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <msub> <mi>N</mi> <mi>t</mi> </msub> </mrow> </semantics></math>.</p> Full article ">Figure 4
<p>BER over SNR under different schemes for different schemes.</p> Full article ">Figure 5
<p>BER over SNR under different schemes for different <math display="inline"><semantics> <mi>v</mi> </semantics></math>.</p> Full article ">Figure 6
<p>BER over SNR under different schemes for different <math display="inline"><semantics> <mrow> <msub> <mi>N</mi> <mi>a</mi> </msub> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <msub> <mi>N</mi> <mi>t</mi> </msub> </mrow> </semantics></math>.</p> Full article ">
12 pages, 5375 KiB  
Article
A 1.2-µW 41-dB Ripple Attenuation Chopper Amplifier Using Auto-Zero Offset Cancelation Loop for Area-Efficient Biopotential Sensing
by Xuan Thanh Pham, Trung Kien Vu, Tien Dzung Nguyen and Loan Pham-Nguyen
Electronics 2022, 11(7), 1149; https://doi.org/10.3390/electronics11071149 - 6 Apr 2022
Cited by 10 | Viewed by 3091
Abstract
In this paper, a low-power and low-noise capacitive-coupled chopper instrumentation amplifier (CCIA) is proposed for biopotential sensing applications. A chopping technique is applied to mitigate the domination of flicker noise at low frequency. A new offset cancellation loop is also used to deal [...] Read more.
In this paper, a low-power and low-noise capacitive-coupled chopper instrumentation amplifier (CCIA) is proposed for biopotential sensing applications. A chopping technique is applied to mitigate the domination of flicker noise at low frequency. A new offset cancellation loop is also used to deal with the intrinsic offset, originating from process variation, to reduce ripple noise at the output of CCIA. Moreover, the optimization of the chip area was resolved by adding a T-network capacitor in the negative feedback loop. The CCIA is designed on 0.18 µm process CMOS technology with a total chip area of 0.09 mm2. The post-simulation results show that the proposed architecture can attenuate the output ripple up to 41 dB with a closed-loop gain of 40 dB and up to 800 Hz of bandwidth. The integrated input referred noise (IRN) of the CCIA is 1.8 µVrms over a bandwidth of 200 Hz. A noise efficiency factor (NEF) of 5.4 is obtained with a total power dissipation of 1.2 µW and a supply voltage of 1 V, corresponding to a power efficiency factor of 9.7 that is comparable with that of state-of-the-art studies. Full article
(This article belongs to the Special Issue Ultra-Low Voltage CMOS Front-End Design)
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<p>Block diagram of a biopotential acquisition system.</p> Full article ">Figure 2
<p>Schematic of the proposed CCIA using A-OCL. C<sub>in1,2</sub> = 2 pF, C<sub>fbeq1,2</sub> = 20 fF, C<sub>m1,2</sub> = 1.5 pF.</p> Full article ">Figure 3
<p>Schematic of the main path of CCIA with the block of proposed A-OCL.</p> Full article ">Figure 4
<p>Schematic of the auto-zero offset A-Gm3 and timing diagram.</p> Full article ">Figure 5
<p>Schematic of the feedback T-network capacitor. (<b>a</b>) Conventional configuration; (<b>b</b>) modified configuration for symmetrical parasitic behavior.</p> Full article ">Figure 6
<p>Schematic of the folded cascode op amp using buck control with its noise sources.</p> Full article ">Figure 7
<p>Schematic of the two-stage OTA G<sub>m3</sub> in A-OCL.</p> Full article ">Figure 8
<p>Chip layout of the proposed CCIA.</p> Full article ">Figure 9
<p>Open-loop simulation results for gain (<b>a</b>) and phase (<b>b</b>) versus frequency of main path amplifier with active A-OCL.</p> Full article ">Figure 10
<p>The simulation results of the proposed CCIA: (<b>a</b>) the frequency response; (<b>b</b>) the input referred noise.</p> Full article ">Figure 11
<p>Monte Carlo simulation results of the mid-band gain of the proposed CCIA for different values of V<sub>DD</sub>: (<b>a</b>) V<sub>DD</sub> = 1 V, (<b>b</b>) V<sub>DD</sub> = 0.9 V, and (<b>c</b>) V<sub>DD</sub> = 1.1 V.</p> Full article ">Figure 11 Cont.
<p>Monte Carlo simulation results of the mid-band gain of the proposed CCIA for different values of V<sub>DD</sub>: (<b>a</b>) V<sub>DD</sub> = 1 V, (<b>b</b>) V<sub>DD</sub> = 0.9 V, and (<b>c</b>) V<sub>DD</sub> = 1.1 V.</p> Full article ">Figure 12
<p>The input referred noise of the proposed CCIA: (<b>a</b>) Depending on the process corners; (<b>b</b>) Monte Carlo simulation results.</p> Full article ">Figure 13
<p>Monte Carlo simulation results of the proposed CCIA: (<b>a</b>) Common mode rejection ratio CMRR; (<b>b</b>) power supply rejection ratio PSRR.</p> Full article ">Figure 14
<p>Simulation results of the proposed CCIA: (<b>a</b>) Spectrum output voltage with and without A-OCL; (<b>b</b>) Monte Carlo simulation of the attenuation ripple.</p> Full article ">Figure 15
<p>Linearity verification by applying FFT analysis of output voltage with 100 Hz input frequency.</p> Full article ">
15 pages, 5306 KiB  
Article
Accelerated Diagnosis of Novel Coronavirus (COVID-19)—Computer Vision with Convolutional Neural Networks (CNNs)
by Arfan Ghani, Akinyemi Aina, Chan Hwang See, Hongnian Yu and Simeon Keates
Electronics 2022, 11(7), 1148; https://doi.org/10.3390/electronics11071148 - 6 Apr 2022
Cited by 12 | Viewed by 2689
Abstract
Early detection and diagnosis of COVID-19, as well as the exact separation of non-COVID-19 cases in a non-invasive manner in the earliest stages of the disease, are critical concerns in the current COVID-19 pandemic. Convolutional Neural Network (CNN) based models offer a remarkable [...] Read more.
Early detection and diagnosis of COVID-19, as well as the exact separation of non-COVID-19 cases in a non-invasive manner in the earliest stages of the disease, are critical concerns in the current COVID-19 pandemic. Convolutional Neural Network (CNN) based models offer a remarkable capacity for providing an accurate and efficient system for the detection and diagnosis of COVID-19. Due to the limited availability of RT-PCR (Reverse transcription-polymerase Chain Reaction) tests in developing countries, imaging-based techniques could offer an alternative and affordable solution to detect COVID-19 symptoms. This paper reviewed the current CNN-based approaches and investigated a custom-designed CNN method to detect COVID-19 symptoms from CT (Computed Tomography) chest scan images. This study demonstrated an integrated method to accelerate the process of classifying CT scan images. In order to improve the computational time, a hardware-based acceleration method was investigated and implemented on a reconfigurable platform (FPGA). Experimental results highlight the difference between various approximations of the design, providing a range of design options corresponding to both software and hardware. The FPGA-based implementation involved a reduced pre-processed feature vector for the classification task, which is a unique advantage of this particular application. To demonstrate the applicability of the proposed method, results from the CPU-based classification and the FPGA were measured separately and compared retrospectively. Full article
(This article belongs to the Collection Deep Learning for Computer Vision: Algorithms, Theory and Application)
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<p>Examples of COVID-19 signatures in CT scans (red rectangles indicate GGO).</p> Full article ">Figure 2
<p>Region analysis of thresholding image as a binary file (positive COVID scan).</p> Full article ">Figure 3
<p>Different resolutions of the pre-processed images by using multi-level thresholding.</p> Full article ">Figure 4
<p>Binary image after using a median filter kernel size 10 × 10.</p> Full article ">Figure 5
<p>Scatter plot of COVID and non-COVID features (orange dots show COVID and blue dots show non-COVID features).</p> Full article ">Figure 6
<p>Original and Filtered Image (<b>top</b>) and second-order approximation of wavelet transform (<b>bottom</b>).</p> Full article ">Figure 7
<p>GoogLeNet training accuracy.</p> Full article ">Figure 8
<p>The loss rate.</p> Full article ">Figure 9
<p>Results of the 40 × 40 input image based on the CNN model.</p> Full article ">Figure 10
<p>Software architecture of the CNN.</p> Full article ">Figure 11
<p>Customized CNN hardware implementation.</p> Full article ">Figure 12
<p>Workflow of the proposed CNN software and hardware implementation.</p> Full article ">Figure 13
<p>Layer structure and processes of the custom CNN.</p> Full article ">Figure 14
<p>Overall system pipeline.</p> Full article ">Figure 15
<p>Simulation of the FPGA based CNN implementation.</p> Full article ">
15 pages, 4843 KiB  
Article
A Real-Coding Population-Based Incremental Learning Evolutionary Algorithm for Multi-Satellite Scheduling
by Yuqing Li, Xiaoen Feng, Gang Wang, Dong Yan, Pengpeng Liu and Chao Zhang
Electronics 2022, 11(7), 1147; https://doi.org/10.3390/electronics11071147 - 6 Apr 2022
Cited by 7 | Viewed by 1875
Abstract
With the increasing demand for earth observation in various fields, remote satellites play an important role in ground information assurance. Apparently, the effective scheduling and utilization of multi-satellite resources determine the quality and efficiency of information acquisition. In this paper, focusing on the [...] Read more.
With the increasing demand for earth observation in various fields, remote satellites play an important role in ground information assurance. Apparently, the effective scheduling and utilization of multi-satellite resources determine the quality and efficiency of information acquisition. In this paper, focusing on the problem of centralized multi-satellite scheduling, we establish a mathematical model of satellite scheduling with complex constraints of load and platform operation. We also propose a real-coding Population Incremental Based Learning (PBIL) algorithm to solve the multi-satellite scheduling problem. The real-coding format can greatly shorten the coding length compared to the traditional PBIL algorithm with binary coding so that the computational efficiency is improved. Additionally, we design a value probability matrix, correction coefficient and mutation operator to guide better evolution and avoid early convergence. Finally, we take some numerical examples to verify the real-coding PBIL algorithm for multi-satellite scheduling. The performance of the algorithm is analyzed by comparing it with binary-coding PBIL and the Genetic Algorithm (GA). Additionally, the influence of key parameters on algorithm performance, such as probability correction coefficient, is also analyzed. Full article
(This article belongs to the Section Computer Science & Engineering)
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<p>Binary-coding format of PBIL algorithm for multi-satellite scheduling.</p> Full article ">Figure 2
<p>Real coding format of PBIL algorithm for multi-satellite scheduling.</p> Full article ">Figure 3
<p>The initial probability matrix.</p> Full article ">Figure 4
<p>The probability matrix update of the second generation.</p> Full article ">Figure 5
<p>Mutation operator.</p> Full article ">Figure 6
<p>The algorithm flow chart of the PBIL algorithm.</p> Full article ">Figure 7
<p>The distribution of the satellites in STK.</p> Full article ">Figure 8
<p>The distribution of the targets in STK.</p> Full article ">Figure 9
<p>The distribution of the ground stations in STK.</p> Full article ">Figure 10
<p>This is the typical simulation results of multi-satellite scheduling based on a real-coding PBIL algorithm: (<b>a</b>) Evolution curve of the algorithm, a description of the optimization process, in which x-coordinate is iterations, and y-coordinate is fitness (corresponding to the scheduling results); (<b>b</b>) Gantt chart of multi-satellite scheduling results, in which x-coordinate is time, and y-coordinate is satellite ID, each colored rectangle represents a satellite mission, with a number next to it is the ground targets ID observed by that mission.</p> Full article ">Figure 11
<p>The influence curve of different probability correction coefficients in the PBIL algorithm.</p> Full article ">Figure 12
<p>The evolutionary curves of the comparison experiments.</p> Full article ">Figure 13
<p>The statistical results of the comparison experiments.</p> Full article ">
17 pages, 2024 KiB  
Article
A Hybrid Deep Learning-Based Approach for Brain Tumor Classification
by Asaf Raza, Huma Ayub, Javed Ali Khan, Ijaz Ahmad, Ahmed S. Salama, Yousef Ibrahim Daradkeh, Danish Javeed, Ateeq Ur Rehman and Habib Hamam
Electronics 2022, 11(7), 1146; https://doi.org/10.3390/electronics11071146 - 5 Apr 2022
Cited by 171 | Viewed by 11001
Abstract
Brain tumors (BTs) are spreading very rapidly across the world. Every year, thousands of people die due to deadly brain tumors. Therefore, accurate detection and classification are essential in the treatment of brain tumors. Numerous research techniques have been introduced for BT detection [...] Read more.
Brain tumors (BTs) are spreading very rapidly across the world. Every year, thousands of people die due to deadly brain tumors. Therefore, accurate detection and classification are essential in the treatment of brain tumors. Numerous research techniques have been introduced for BT detection as well as classification based on traditional machine learning (ML) and deep learning (DL). The traditional ML classifiers require hand-crafted features, which is very time-consuming. On the contrary, DL is very robust in feature extraction and has recently been widely used for classification and detection purposes. Therefore, in this work, we propose a hybrid deep learning model called DeepTumorNet for three types of brain tumors (BTs)—glioma, meningioma, and pituitary tumor classification—by adopting a basic convolutional neural network (CNN) architecture. The GoogLeNet architecture of the CNN model was used as a base. While developing the hybrid DeepTumorNet approach, the last 5 layers of GoogLeNet were removed, and 15 new layers were added instead of these 5 layers. Furthermore, we also utilized a leaky ReLU activation function in the feature map to increase the expressiveness of the model. The proposed model was tested on a publicly available research dataset for evaluation purposes, and it obtained 99.67% accuracy, 99.6% precision, 100% recall, and a 99.66% F1-score. The proposed methodology obtained the highest accuracy compared with the state-of-the-art classification results obtained with Alex net, Resnet50, darknet53, Shufflenet, GoogLeNet, SqueezeNet, ResNet101, Exception Net, and MobileNetv2. The proposed model showed its superiority over the existing models for BT classification from the MRI images. Full article
(This article belongs to the Special Issue Intelligent Data Sensing, Processing, Mining, and Communication)
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<p>Three different tumors (meningioma, glioma, and pituitary tumor) in three different views.</p> Full article ">Figure 2
<p>Architecture of proposed hybrid model.</p> Full article ">Figure 3
<p>Classification performance (accuracy (%)) of the proposed hybrid model.</p> Full article ">Figure 4
<p>Diagram of transfer learning-based classification.</p> Full article ">
14 pages, 812 KiB  
Article
ASMAC: An Adaptive Slot Access MAC Protocol in Distributed VANET
by Shi-Yuan Han and Chang-Yue Zhang
Electronics 2022, 11(7), 1145; https://doi.org/10.3390/electronics11071145 - 5 Apr 2022
Cited by 5 | Viewed by 2907
Abstract
The media access control (MAC) protocol is responsible for channel resource sharing and conflict management in the communication process in VANET, which is of great significance for ensuring efficient and reliable communication. The existing MAC protocol with fixed time slot allocation cannot solve [...] Read more.
The media access control (MAC) protocol is responsible for channel resource sharing and conflict management in the communication process in VANET, which is of great significance for ensuring efficient and reliable communication. The existing MAC protocol with fixed time slot allocation cannot solve the problem of time slot resource exhaustion or waste when the traffic density is unbalanced. In this paper, we propose an adaptive time slot access MAC protocol in distributed VANET (ASMAC). ASMAC adapts the access time slot according to the driving direction of the vehicle and the traffic density ratio to improve the time slot access efficiency. In the ASMAC protocol, the frame is divided into several time slots based on TDMA, and the time slots in a frame are divided into two time slot sets according to the driving direction. The vehicle selects a time slot access corresponding to the time slot set. When the vehicle finds that there is no accessible time slot in the time slot set, it accesses the available time slot in the reverse time slot set to improve the efficiency of time slot access. In this paper, the analysis and simulation results of highway and four-way intersection scenarios are given and the validity of the ASMAC protocol is verified by comparing with the VeMAC and SAMD protocols. Full article
(This article belongs to the Special Issue Network Protocols for Wireless Sensor Networks)
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<p>The structure of a VANET.</p> Full article ">Figure 2
<p>The directions of vehicle movement.</p> Full article ">Figure 3
<p>The time slot in a frame is divided into two time slot sets.</p> Full article ">Figure 4
<p>Vehicle communication in balanced traffic flow scenario.</p> Full article ">Figure 5
<p>Vehicle communication in unbalanced traffic flow scenario.</p> Full article ">Figure 6
<p>Packet reception rate and the number of collision on highway. (<b>a</b>) Packet reception rate. (<b>b</b>) Collisions.</p> Full article ">Figure 7
<p>Packet reception rate and the number of collision on highway. (<b>a</b>) Packet reception rate. (<b>b</b>) Collisions.</p> Full article ">Figure 8
<p>(<b>a</b>) Packet reception rate and (<b>b</b>) delay under different traffic density ratios when the number of vehicles is 200.</p> Full article ">Figure 9
<p>(<b>a</b>) Packet reception rate and (<b>b</b>) delay under different traffic density ratios when the number of vehicles is 400.</p> Full article ">Figure 10
<p>(<b>a</b>) Packet reception rate and (<b>b</b>) delay under different traffic density ratios when the number of vehicles is 600.</p> Full article ">
22 pages, 12748 KiB  
Article
Methods to Improve Dynamic System Response of Power Compensators Using Supercapacitors in Low-Voltage Ride-Through (LVRT) Conditions
by Mi-na Kim, Jun-sin Yi, Chung-Yuen Won and Jung-Hyo Lee
Electronics 2022, 11(7), 1144; https://doi.org/10.3390/electronics11071144 - 5 Apr 2022
Cited by 2 | Viewed by 2189
Abstract
In this paper, a power compensator using supercapacitors in parallel to protect grid-connected devices connected to the distributed power supply in the case of a low-voltage ride-through (LVRT) situation in designed, and a grid-connected device control method with improved responsiveness is proposed. In [...] Read more.
In this paper, a power compensator using supercapacitors in parallel to protect grid-connected devices connected to the distributed power supply in the case of a low-voltage ride-through (LVRT) situation in designed, and a grid-connected device control method with improved responsiveness is proposed. In the LVRT situation, the distributed generation power may boost the DC_link voltage, increasing the risk of destroying grid-connected devices. To prevent this, the power compensator designed in this study absorbs active power in a fault situation and stores it in the supercapacitor to suppress the DC_link voltage rise and efficiently use the power. In addition, we propose methods to improve the response of the grid reactive power through the reactive power compensation of the power compensator in LVRT situation. To this end, the power angle (θPW) was extracted through the formula, and the reactive power command, to be compensated by the power compensator, and the reactive power command, compensated by the grid-connected devices, were calculated according to the active power value. In this way, the grid power controlled by the power compensation device and the grid-connected devices was controlled by the active/reactive power of the same power angle and analyzed mathematically. Active power control and static grid support were performed in the normal state where the reduction rate of the normal value of the grid voltage was around 10%. However, when the grid voltage dropped by 10% to 100%, the reactive power control was appropriately performed with dynamic grid support by increasing the voltage from 10% to 20% or more. We conducted a simulation of the new and renewable energy grid-connected devices using the OPAL-RT-based Hardware-in-the Loop Simulation (HILS) system to control the proposed active/reactive power. Full article
(This article belongs to the Section Power Electronics)
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<p>Requirements for FRT by German Grid Code.</p> Full article ">Figure 2
<p>German Grid Code: (<b>a</b>) principle of grid voltage support; (<b>b</b>) reactive current to grid voltage regulation.</p> Full article ">Figure 3
<p>DC_link voltage fluctuation in each situation: (<b>a</b>) steady condition; (<b>b</b>) LVRT condition.</p> Full article ">Figure 4
<p>Full block diagram of power compensators and grid-connected devices.</p> Full article ">Figure 5
<p>Equivalent circuit of 3-phase AC–DC converter.</p> Full article ">Figure 6
<p>dq axis vector control.</p> Full article ">Figure 7
<p>Control block diagram of grid-connected devices in distributed generation.</p> Full article ">Figure 8
<p>Calculation block diagram for distributed power generation.</p> Full article ">Figure 9
<p>Detailed block diagram of a power distributor.</p> Full article ">Figure 10
<p>Three-phase grid voltage and current phasor diagram.</p> Full article ">Figure 11
<p>Size of reactive power according to active power.</p> Full article ">Figure 12
<p>Calculation of compensation power supercapacitor.</p> Full article ">Figure 13
<p>Algorithm block diagram for power compensator control.</p> Full article ">Figure 14
<p>Block diagram for the charging control mode of a power compensator.</p> Full article ">Figure 15
<p>Active/reactive power control simulator for grid-connected devices.</p> Full article ">Figure 16
<p>Results of active and reactive power control of grid-connected devices.</p> Full article ">Figure 17
<p>Overall graph of varying grid voltage and current.</p> Full article ">Figure 18
<p>Results of simulation experiment for each variable section of grid voltage and current.</p> Full article ">Figure 19
<p>Comparison of dynamic grid support and simulation test results for each section.</p> Full article ">Figure 20
<p>DC_link voltage.</p> Full article ">Figure 21
<p>Simulation block diagram of power compensator control.</p> Full article ">Figure 22
<p>Simulation results of supercapacitor voltage/current.</p> Full article ">Figure 23
<p>Simulation results of active/reactive power.</p> Full article ">Figure 24
<p>Simulation results of dq axis current.</p> Full article ">Figure 25
<p>Response of proposed grid-connected devices for distributed generation.</p> Full article ">Figure 26
<p>OPAL-RT block diagram of a grid-connected device including the proposed power compensator.</p> Full article ">Figure 27
<p>OPAL-RT test step.</p> Full article ">Figure 28
<p>Phase voltage, current, and reactive current response results for independent operation depending on grid voltages.</p> Full article ">Figure 29
<p>Response results of the proposed grid-connected devices depending on grid voltages.</p> Full article ">
17 pages, 1011 KiB  
Article
OntoDomus: A Semantic Model for Ambient Assisted Living System Based on Smart Homes
by Hubert Kenfack Ngankam, Hélène Pigot and Sylvain Giroux
Electronics 2022, 11(7), 1143; https://doi.org/10.3390/electronics11071143 - 5 Apr 2022
Cited by 14 | Viewed by 3128
Abstract
Ambient assisted living (AAL) makes it possible to build assistance for older adults according to the person’s context. Understanding the person’s context sometimes involves transforming one’s home into a smart home. Typically, this is carried out using nonintrusively distributed sensors and calm technologies. [...] Read more.
Ambient assisted living (AAL) makes it possible to build assistance for older adults according to the person’s context. Understanding the person’s context sometimes involves transforming one’s home into a smart home. Typically, this is carried out using nonintrusively distributed sensors and calm technologies. Older adults often have difficulty performing activities of daily living, such as taking medication, drinking coffee, watching television, using certain electronic devices, and dressing. This difficulty is even greater when these older adults suffer from cognitive impairments. Defining an assistance solution requires a multidisciplinary and iterative collaborative approach. It is necessary, therefore, to reason about the imperatives and solutions of this multidisciplinary collaboration (e.g., clinical), as well as the adaptation of technical constraints (e.g., technologies). A common approach to reasoning is to represent knowledge using logic-based formalisms, such as ontologies. However, there is not yet an established ontology that defines concepts such as multidisciplinary collaboration in successive stages of the assistance process. This article presents OntoDomus, an ontology that describes, at several levels, the semantic interactions between ambient assisted living, context awareness, smart home, and Internet of Things, based on multidisciplinarity. It revolves around two main notions: multidisciplinarity, based on specific sub-ontologies and the ambient feedback loop. OntoDomus combines SPARQL queries and OWL 2 models to improve the reusability of domain terminology, allowing stakeholders to represent their knowledge in different collaborative and adaptive situations. The ontological model is validated, first by its reuse in more specific works—specific to an aspect of ambient assistance. Second, it is validated by the structuring of ambient knowledge and inferences of the formalization in a case study that includes instances for a particular activity of daily living. It places the ambient feedback loop at the center of the ontology by focusing on highly expressive domain ontology formalisms with a low level of expressiveness between them. Full article
(This article belongs to the Special Issue Intelligent Surveillance and Smart Home)
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<p>Ambient assisted living feedback loop.</p> Full article ">Figure 2
<p>Global view of <span class="html-italic">OntoDomus</span> ontology.</p> Full article ">Figure 3
<p>Formal definition of a room.</p> Full article ">Figure 4
<p>Formal definition of a script.</p> Full article ">Figure 5
<p>Semantic ambient reasoning framework.</p> Full article ">Figure 6
<p>Vocabulary about getting out of bed.</p> Full article ">Figure 7
<p>3D representation of the smart home based on <span class="html-italic">OntoDomus</span>.</p> Full article ">Figure 8
<p>Instantiation of the <span class="html-italic">OntoDomus</span> for the out of bed case.</p> Full article ">Figure 9
<p>SPARQL query example.</p> Full article ">
15 pages, 4417 KiB  
Article
An End-to-End Video Steganography Network Based on a Coding Unit Mask
by Huanhuan Chai, Zhaohong Li, Fan Li and Zhenzhen Zhang
Electronics 2022, 11(7), 1142; https://doi.org/10.3390/electronics11071142 - 5 Apr 2022
Cited by 12 | Viewed by 3267
Abstract
Steganography hides secret messages inside the covers while ensuring imperceptibility. Different from traditional steganography, deep learning-based steganography has an adaptable and generalized framework without needing expertise regarding the embedding process. However, most steganography algorithms utilize images as covers instead of videos, which are [...] Read more.
Steganography hides secret messages inside the covers while ensuring imperceptibility. Different from traditional steganography, deep learning-based steganography has an adaptable and generalized framework without needing expertise regarding the embedding process. However, most steganography algorithms utilize images as covers instead of videos, which are more expressive and more widely spread. To this end, an end-to-end deep learning network for video steganography is proposed in this paper. A multiscale down-sampling feature extraction structure is designed, which consists of three parts including an encoder, a decoder, and a discriminator network. Furthermore, in order to facilitate the learning ability of network, a CU (coding unit) mask built from a VVC (versatile video coding) video is first introduced. In addition, an attention mechanism is used to further promote the visual quality. The experimental results show that the proposed steganography network can achieve a better performance in terms of the perceptual quality of stego videos, decoding the accuracy of hidden messages, and the relatively high embedding capacity compared with the state-of-the-art steganography networks. Full article
(This article belongs to the Special Issue Digital and Optical Security Algorithms via Machine Learning)
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<p>Architecture of the proposed PyraGAN.</p> Full article ">Figure 2
<p>The CU mask of one video frame.</p> Full article ">Figure 3
<p>Convolutional block attention mechanism.</p> Full article ">Figure 4
<p>The encoder component of PyraGAN.</p> Full article ">Figure 5
<p>The decoder component of PyraGAN.</p> Full article ">Figure 6
<p>The discriminator component of PyraGAN.</p> Full article ">Figure 7
<p>VVC compressed reconstructed video frame and corresponding CU mask.</p> Full article ">Figure 8
<p>The visual quality of steganographic video frame of PyraGAN.</p> Full article ">
12 pages, 785 KiB  
Article
An Efficient Simulation-Based Policy Improvement with Optimal Computing Budget Allocation Based on Accumulated Samples
by Xilang Huang and Seon Han Choi
Electronics 2022, 11(7), 1141; https://doi.org/10.3390/electronics11071141 - 4 Apr 2022
Cited by 1 | Viewed by 1901
Abstract
Markov decision processes (MDPs) are widely used to model stochastic systems to deduce optimal decision-making policies. As the transition probabilities are usually unknown in MDPs, simulation-based policy improvement (SBPI) using a base policy to derive optimal policies when the state transition probabilities are [...] Read more.
Markov decision processes (MDPs) are widely used to model stochastic systems to deduce optimal decision-making policies. As the transition probabilities are usually unknown in MDPs, simulation-based policy improvement (SBPI) using a base policy to derive optimal policies when the state transition probabilities are unknown is suggested. However, estimating the Q-value of each action to determine the best action in each state requires many simulations, which results in efficiency problems for SBPI. In this study, we propose a method to improve the overall efficiency of SBPI using optimal computing budget allocation (OCBA) based on accumulated samples. Previous works have mainly focused on improving SBPI efficiency for a single state and without using the previous simulation samples. In contrast, the proposed method improves the overall efficiency until an optimal policy can be found in consideration of the state traversal property of the SBPI. The proposed method accumulates simulation samples across states to estimate the unknown transition probabilities. These probabilities are then used to estimate the mean and variance of the Q-value for each action, which allows the OCBA to allocate the simulation budget efficiently to find the best action in each state. As the SBPI traverses the state, the accumulated samples allow appropriate allocation of OCBA; thus, the optimal policy can be obtained with a lower budget. The experimental results demonstrate the improved efficiency of the proposed method compared to previous works. Full article
(This article belongs to the Special Issue Advances in Stochastic System Modeling, Control, Optimization, and Their Applications)
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<p>An example of MDP, where a circle represents a state and a square represents an action that is available in the state. <span class="html-italic">P</span> represents an unknown state transition probability, a reward is denoted by <span class="html-italic">r</span>, and <math display="inline"><semantics> <mi>π</mi> </semantics></math> is the policy.</p> Full article ">Figure 2
<p>Table of the cumulative number of state–action pairs, where 0 represents the unreachable states.</p> Full article ">Figure 3
<p>A two-state Markov decision process.</p> Full article ">Figure 4
<p>An extended version of the two-state example.</p> Full article ">Figure 5
<p>Graphs indicate the value function of the improved policy and <math display="inline"><semantics> <mrow> <mi>P</mi> <mfenced separators="" open="{" close="}"> <mi>C</mi> <mi>S</mi> </mfenced> </mrow> </semantics></math> of each method for the two examples: (<b>A</b>,<b>B</b>) the results of the two-state example; (<b>C</b>,<b>D</b>) the results of the extended version.</p> Full article ">
15 pages, 3506 KiB  
Article
Analysis of LED Lamps’ Sensitivity to Surge Impulse
by Wiesław Sabat, Dariusz Klepacki, Kazimierz Kamuda and Kazimierz Kuryło
Electronics 2022, 11(7), 1140; https://doi.org/10.3390/electronics11071140 - 4 Apr 2022
Cited by 4 | Viewed by 2387
Abstract
The results of research on the influence of the 1.2/50 µs (8/20 µs) surge impulse on the reliability of commercial LED lamps are presented in the paper. For two types of lamps, differing in the declared warranty period, tests were carried out in [...] Read more.
The results of research on the influence of the 1.2/50 µs (8/20 µs) surge impulse on the reliability of commercial LED lamps are presented in the paper. For two types of lamps, differing in the declared warranty period, tests were carried out in which it was determined how the impulse of 1.2/50 µs (8/20 µs) is propagated in their supply systems. During the tests, the effects it causes on the critical levels and how its level influences the probability of failure of the tested lamp were examined. These solutions are currently being used in mass production of LED lamps and are characteristic of budget devices. Sensitivity tests were conducted for a group of 150 lamps divided evenly into 10 batches. The tests were carried out in accordance with the standards of EN 61000-4-5: 2014 and EN 61547: 2009 with one exception: the impulse level was not limited to the 0.5 kV recommended in EN 61547: 2009 for this class of components, but increased to a value that leads to permanent damage. These tests allowed us to determine the margin from the value specified in the standard to the sensitivity of the tested lamps on this type of disturbance. Full article
(This article belongs to the Section Microelectronics)
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<p>Electric diagram of the power supply of tested lamps: (<b>a</b>) type A, (<b>b</b>) type B.</p> Full article ">Figure 2
<p>Stand for immunity testing of LED lamps to 1.2/50 µs/(8/20 µs) using the UCS500N5 generator by EMTest.</p> Full article ">Figure 3
<p>(<b>a</b>) Voltage and (<b>b</b>) current waveforms at selected test points (marked in <a href="#electronics-11-01140-f001" class="html-fig">Figure 1</a>a) for lamp A for a surge of 1.2/50 µs (8/20 µs) injected at the top of the mains voltage sinusoid.</p> Full article ">Figure 4
<p>(<b>a</b>) Voltage and (<b>b</b>) current waveforms at selected test points (marked in <a href="#electronics-11-01140-f001" class="html-fig">Figure 1</a>b) for lamp B for a surge of 1.2/50 µs (8/20 µs) injected at the top of the mains voltage sinusoid.</p> Full article ">Figure 5
<p>Configurations of test systems for measuring the immunity of elements to a surge of 1.2/50 µs (8/20 µs): (<b>a</b>) resistors, (<b>b</b>) capacitors, (<b>c</b>) diodes, (<b>d</b>) rectifier bridge, (<b>e</b>) current stabilizer.</p> Full article ">Figure 6
<p>Sensitivity of the components of lamp A and B to a surge of 1.2/50 µs (8/20 µs): (<b>a</b>,<b>b</b>) resistors, (<b>c</b>) capacitors, (<b>d</b>) LEDs, (<b>e</b>) rectifiers, (<b>f</b>) current stabilizers.</p> Full article ">Figure 7
<p>Physical failure effects of test components for critical surge levels.</p> Full article ">Figure 8
<p>The results of the statistical analysis of damage of the integral parts of individual components of the type A lamp.</p> Full article ">Figure 9
<p>The results of the statistical analysis of damage of the integral parts of individual components of the type B lamp.</p> Full article ">Figure 10
<p>Distribution of empirical distribution F*(Us) and theoretical F(Us) and theoretical strength function R(Us): (<b>a</b>) LED lamp A, (<b>b</b>) LED lamp B.</p> Full article ">Figure 11
<p>Correlation between the value of the voltage surge and the number of failures: LED lamp A (<b>a</b>) and LED lamp B (<b>b</b>).</p> Full article ">
14 pages, 4298 KiB  
Article
Fast Readout of Split-Ring Resonators Made Simple and Low-Cost for Application in HPLC
by Moritz Hitzemann, Kirsten J. Dehning, Adrian V. Gehl, Erk-Fietje Sterr and Stefan Zimmermann
Electronics 2022, 11(7), 1139; https://doi.org/10.3390/electronics11071139 - 4 Apr 2022
Cited by 4 | Viewed by 2578
Abstract
Split-ring resonators (SRR) are simple electrical circuits that show a significant shift in resonance frequency even with the smallest changes in split capacitance, and thus in permittivity, electric conductivity, and dielectric losses of the split capacitor’s dielectric. Usually, the resonance frequency is derived [...] Read more.
Split-ring resonators (SRR) are simple electrical circuits that show a significant shift in resonance frequency even with the smallest changes in split capacitance, and thus in permittivity, electric conductivity, and dielectric losses of the split capacitor’s dielectric. Usually, the resonance frequency is derived from the frequency response, but recording the frequency spectrum takes a certain amount of time. Here, we present a new capillary split-ring resonator CaSRR with fast readout for liquid chromatography (LC), which is capable of accurately detecting very fast changes in split capacity. The proposed method is based on the detection of the transmitted signal at a single frequency that is analyzed by demodulation. The demodulated signal changes its amplitude depending on the shift of the resonance frequency. Our simple low-cost electronics enables an average sampling rate of 42 Hz with 128 averages of the demodulated signal and has a frequency stability of 840 mHz. Thus, a minimum change in permittivity of Δεr,min = 11.26 × 10−3 can be detected. Finally, a chromatogram of one sugar (glucose) and one sugar alcohol (xylitol) is recorded using the SRR and is compared to a standard refractive index detector. Full article
(This article belongs to the Section Industrial Electronics)
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<p>Schematic of the capillary split-ring resonator (CaSRR) with a transmission line on RO4003C PCB and a split-ring made of copper capillaries. The split capacitor is formed inside a Vici Valco PEEK union with an inner diameter of 1.6 mm by the two opposite capillary endings.</p> Full article ">Figure 2
<p>Basic concept of the new readout electronics consisting of a frequency-controlled sine-wave generator, the CaSRR, a demodulator (envelope detector), and an ADC.</p> Full article ">Figure 3
<p>Block diagram of the developed new readout electronics, consisting of an oven-controlled oscillator (OCXO), the Analog Devices MAX2871 integrated PLL/VCO chip, an adjustable low-pass filter for filtering the harmonics, and an adjustable amplifier for the output. Both the output signal of the excitation source (CaSRR input) and the transmitted output signal of the CaSRR are recorded with demodulators.</p> Full article ">Figure 4
<p>Circuit diagram of the input section including the power detector with the corresponding components and the ADC for analog-to-digital conversion.</p> Full article ">Figure 5
<p>PCB of the new readout electronics (photo, top view) including all components required for power supply, control, and data acquisition.</p> Full article ">Figure 6
<p>Schematic layout of the Knaur HPLC with the built-in SRR. The dead volumes between the HPLC column and the refractive index detector are as follows. (1) 30 cm capillary with inner diameter of 250 µm giving a dead volume of 14.7 µL, (2a) SRR capillary volume of 8.6 µL, (2b) split capacitor volume of 2.3 µL, and (3) 50 cm connecting capillary with inner diameter 250 µm giving a dead volume of 24.5 µL.</p> Full article ">Figure 7
<p>Output signal of new readout electronics measured at 1.0000005265 GHz over a time of 20 s. The left diagram shows the maximum frequency delta of 840 mHz and the right diagram shows that the amplitude is very stable with a maximum change from −27.8868 dBm to −27.8846 dBm.</p> Full article ">Figure 8
<p>(<b>a</b>) Measured (red squares) and fitted (black curve) transmission response of the CaSRR loaded with 25% ultrapure water and 75% acetonitrile used as an eluent in the HPLC experiments. The resonance frequency was 789.5 MHz, and the maximum attenuation was −5.246 dB. The green circles marked the optimum excitation frequencies below and above the resonance frequency for the highest sensitivity regarding the detection of resonance frequency shifts. (<b>b</b>) Differentiation of the measured and fitted CaSRR transmission response of the CaSRR loaded with eluent. The inflection points for the measured curve are at 774.5 MHz and at 801.5 MHz. For the fitted curve, the inflection point frequencies differ slightly, and are 770.264 MHz and 806.378 MHz, respectively.</p> Full article ">Figure 9
<p>(<b>a</b>) Simulated frequency responses of CaSRR for different resonance frequencies (in 140 kHz steps). (<b>b</b>) Difference between the shifted frequency responses from the non-shifted frequency response, both including the impurity of the excitation source. The black lines mark the maximum differences in amplitude and thus the optimum excitation frequencies for the maximum sensitivity.</p> Full article ">Figure 10
<p>Measured transmission response (red) of the CaSRR loaded with the eluent and recorded with the new readout electronics. The resonance frequency was 755 MHz for the used eluent consisting of 25% ultrapure water and 75% acetonitrile, and the attenuation was −4.806 dB. The green circles mark the optimum excitation frequencies at 740 MHz and at 797 MHz for highest sensitivity regarding the detection of resonance frequency shifts.</p> Full article ">Figure 11
<p>(<b>a</b>) Continuous measurement (capillary split ring resonator with new readout electronics) of 2-propanol (0% to 5%) in ultrapure water, giving relative permittivities from <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="sans-serif">ε</mi> <mi mathvariant="normal">r</mi> </msub> <mo>=</mo> <mn>29.3</mn> </mrow> </semantics></math> to <math display="inline"><semantics> <mrow> <msub> <mi mathvariant="sans-serif">ε</mi> <mi mathvariant="normal">r</mi> </msub> <mo>=</mo> <mn>28.77</mn> </mrow> </semantics></math> (<b>b</b>) Mean value (orange cross) of the output signal of each relative permittivity step and linear regression (parameters given in Equation (6)) with an R<sup>2</sup> of 99.42%.</p> Full article ">Figure 12
<p>HPLC chromatogram of 125 mg/mL glucose and 115 mg/mL xylitol in ultrapure water, eluent 75% acetonitrile, 25% ultrapure water at 30 °C, measured with CaSRR (blue) at 740 MHz (inflection point) and refractive index detector (orange).</p> Full article ">
22 pages, 1232 KiB  
Article
Efficient FPGA Implementation of an ANN-Based Demapper Using Cross-Layer Analysis
by Jonas Ney, Bilal Hammoud, Sebastian Dörner, Matthias Herrmann, Jannis Clausius, Stephan ten Brink and Norbert Wehn
Electronics 2022, 11(7), 1138; https://doi.org/10.3390/electronics11071138 - 3 Apr 2022
Cited by 6 | Viewed by 2864
Abstract
In the field of communication, autoencoder (AE) refers to a system that replaces parts of the traditional transmitter and receiver with artificial neural networks (ANNs). To meet the system performance requirements, it is necessary for the AE to adapt to the changing wireless-channel [...] Read more.
In the field of communication, autoencoder (AE) refers to a system that replaces parts of the traditional transmitter and receiver with artificial neural networks (ANNs). To meet the system performance requirements, it is necessary for the AE to adapt to the changing wireless-channel conditions at runtime. Thus, online fine-tuning in the form of ANN-retraining is of great importance. Many algorithms on the ANN layer are developed to improve the AE’s performance at the communication layer. Yet, the link of the system performance and the ANN topology to the hardware layer is not fully explored. In this paper, we analyze the relations between the design layers and present a hardware implementation of an AE-based demapper that enables fine-tuning to adapt to varying channel conditions. As a platform, we selected field-programmable gate arrays (FPGAs) which provide high flexibility and allow to satisfy the low-power and low-latency requirements of embedded communication systems. Furthermore, our cross-layer approach leverages the flexibility of FPGAs to dynamically adapt the degree of parallelism (DOP) to satisfy the system-level requirements and to ensure environmental adaptation. Our solution achieves 2000× higher throughput than a high-performance graphics processor unit (GPU), draws 5× less power than an embedded central processing unit (CPU) and is 5800× more energy efficient compared to an embedded GPU for small batch size. To the best of our knowledge, such a cross-layer design approach combined with FPGA implementation is unprecedented. Full article
(This article belongs to the Special Issue Applications of FPGAs and Reconfigurable Computing: Current Trends and Future Perspectives)
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<p>Digital communication chain.</p> Full article ">Figure 2
<p>Overview of the AE ANN structure.</p> Full article ">Figure 3
<p>ANN topology optimization for different number of neurons compared to 16-QAM.</p> Full article ">Figure 4
<p>Constellations learned by autoencoder for 4 bits per symbol.</p> Full article ">Figure 5
<p>MI of autoencoder constellations compared to channel capacity and 16-QAM.</p> Full article ">Figure 6
<p>FPGA design of the training module.</p> Full article ">Figure 7
<p>Exploration Framework.</p> Full article ">Figure 8
<p>Resource utilization on Ultra96-V2.</p> Full article ">Figure 9
<p>Latency, power and energy on Ultra96-V2.</p> Full article ">Figure 10
<p>Convergence of phase offset for <math display="inline"><semantics> <mrow> <msub> <mi>E</mi> <mi>b</mi> </msub> <mo>/</mo> <msub> <mi>N</mi> <mn>0</mn> </msub> <mo>=</mo> <mn>2</mn> </mrow> </semantics></math>.</p> Full article ">Figure 11
<p>BER over SNR for different number of training iterations.</p> Full article ">Figure 12
<p>Influence of DOP on convergence latency for a target BER of 0.25.</p> Full article ">Figure 13
<p>Throughput comparison.</p> Full article ">Figure 14
<p>Power comparison.</p> Full article ">Figure 15
<p>Energy comparison.</p> Full article ">
15 pages, 7687 KiB  
Article
Gain Function-Based Visual Tracking Control for Inertial Stabilized Platform with Output Constraints and Disturbances
by Xiangyang Liu, Jun Yang and Pengyu Qiao
Electronics 2022, 11(7), 1137; https://doi.org/10.3390/electronics11071137 - 2 Apr 2022
Cited by 4 | Viewed by 2001
Abstract
In this paper, a composite control strategy is proposed to deal with output constraints and disturbances of the visual tracking system for an inertial stabilized platform, which combines active disturbance compensation and the variable gain function technique. Firstly, the model of system considering [...] Read more.
In this paper, a composite control strategy is proposed to deal with output constraints and disturbances of the visual tracking system for an inertial stabilized platform, which combines active disturbance compensation and the variable gain function technique. Firstly, the model of system considering multi-source disturbances is established, where the controlled output is the constrained position of the target in the image plane. Secondly, in order to avoid the tracked target being lost in the field of view of the camera, a control method based on the variable gain function technique is designed to ensure that the controlled output remains within the feasible range. Moreover, the active disturbance estimation and compensation method is introduced to improve the anti-disturbance ability of the system under the situation of small output error, obtaining satisfactory tracking performance. The stability analysis and the proof of constrained output are given following the controller design. Finally, results of simulation and experiments are shown to illustrate the promised advantages of the proposed composite control approach. Full article
(This article belongs to the Section Systems & Control Engineering)
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<p>Reference coordinate system of the visual tracking system for an ISP.</p> Full article ">Figure 2
<p>The control block diagram of the proposed method based on GPIO and gain function.</p> Full article ">Figure 3
<p>Step response curves of undisturbed system under three methods in simulation part: (<b>a</b>) azimuth-axis target position, (<b>b</b>) pitch-axis target position.</p> Full article ">Figure 4
<p>Control inputs of undisturbed system under three methods in simulation part: (<b>a</b>) control input under proposed method, (<b>b</b>) control input under high-gain method, (<b>c</b>) control input under low-gain method.</p> Full article ">Figure 5
<p>Step response curves of disturbed system under two methods in simulation part: (<b>a</b>) azimuth-axis target position, (<b>b</b>) pitch-axis target position.</p> Full article ">Figure 6
<p>Control inputsof disturbed system under two methods in simulation part: (<b>a</b>) control input under proposed method with GPIO, (<b>b</b>) control input under proposed method without GPIO.</p> Full article ">Figure 7
<p>Physical depiction of the experimental equipment of the ISP visual tracking system.</p> Full article ">Figure 8
<p>Step response curves of three methods under large initial output error in Case 1: (<b>a</b>) azimuth-axis target position, (<b>b</b>) pitch-axis target position.</p> Full article ">Figure 9
<p>Response curves of tracking moving target under two methods in Case 2.</p> Full article ">Figure 10
<p>Response curves of tracking high-speed target under two methods in Case 3.</p> Full article ">
16 pages, 5517 KiB  
Article
An Efficient Object Navigation Strategy for Mobile Robots Based on Semantic Information
by Yu Guo, Yuanyan Xie, Yue Chen, Xiaojuan Ban, Balqies Sadoun and Mohammad S. Obaidat
Electronics 2022, 11(7), 1136; https://doi.org/10.3390/electronics11071136 - 2 Apr 2022
Cited by 6 | Viewed by 3088
Abstract
In recent years, the rapid development of computer vision makes it possible for mobile robots to be more intelligent. Among the related technologies, the visual SLAM system allows the mobile robot to locate itself, build the map, and provide a navigation strategy to [...] Read more.
In recent years, the rapid development of computer vision makes it possible for mobile robots to be more intelligent. Among the related technologies, the visual SLAM system allows the mobile robot to locate itself, build the map, and provide a navigation strategy to execute follow-up tasks, such as searching for objects in unknown environment according to the observed information. However, most of the existing studies are meant to provide a predefined trajectory for the robot or allow the robot to explore blindly and randomly, which undoubtedly affects the efficiency of the object navigation process and goes against with the idea of “intelligent”. To solve the above problems, an efficient object navigation strategy is proposed in this paper. Firstly, a semantic association model is obtained by using the Mask R-CNN and skip-gram to conduct correlation analysis of common indoor objects. Then, with the help of the above model and ROS framework, an effective object navigation strategy is designed to enable the robot to find the given target efficiently. Finally, the classical ORB-SLAM2 system method is integrated to help the robot build a high usability environment map and find passable paths when moving. Simulation results validated that the proposed strategy can efficiently help the robot to navigate to the object without human intervention. Full article
(This article belongs to the Special Issue Path Planning for Mobile Robots)
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<p>Overall system framework based on ROS.</p> Full article ">Figure 2
<p>ROS architecture designed in this paper.</p> Full article ">Figure 3
<p>Using object detection to infer relevance: (<b>a</b>) An example of detection results of Mask R-CNN; (<b>b</b>) The position coordinates of different objects.</p> Full article ">Figure 4
<p>An example of how to obtain the training samples.</p> Full article ">Figure 5
<p>The workflow of the decision node.</p> Full article ">Figure 6
<p>The semantic association model for the office places.</p> Full article ">Figure 7
<p>Reliability test results of the semantic association model for the office places.</p> Full article ">Figure 8
<p>The semantic association model for the kitchen places.</p> Full article ">Figure 9
<p>Reliability test results of the semantic association model for the kitchen places.</p> Full article ">Figure 10
<p>The virtual apartment this paper built.</p> Full article ">Figure 11
<p>The moving trajectories of the robot. From left to right: Random Search, Traversal Search, and Autonomous Search.</p> Full article ">Figure 12
<p>The process of the robot navigating to the cup.</p> Full article ">Figure 13
<p>Turtlebot3 robot with Kinect camera.</p> Full article ">Figure 14
<p>Experiment in real scenario.</p> Full article ">
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