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Electronics, Volume 8, Issue 10 (October 2019)

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Open AccessArticle
Impact of Aging on Three-Dimensional Facial Verification
Electronics 2019, 8(10), 1170; https://doi.org/10.3390/electronics8101170 (registering DOI) - 15 Oct 2019
Abstract
Age progression is associated with poor performance of verification systems. Thus, there is a need for further research to overcome this problem. Three-dimensional facial aging modeling for employment in verification systems is highly serviceable, and able to acknowledge how variations in depth and [...] Read more.
Age progression is associated with poor performance of verification systems. Thus, there is a need for further research to overcome this problem. Three-dimensional facial aging modeling for employment in verification systems is highly serviceable, and able to acknowledge how variations in depth and pose can provide additional information to accurately represent faces. In this article, the impact of aging on the performance of three-dimensional facial verification is studied. For this purpose, we employed three-dimensional (3D) faces obtained from a 3D morphable face aging model (3D F-FAM). The proposed 3D F-FAM was able to simulate the facial appearance of a young adult in the future. A performance evaluation was completed based on three metrics: structural texture quality, mesh geometric distortion and morphometric landmark distances. The collection of 500 textured meshes from 145 subjects, which were used to construct our own database called FaceTim V.2.0, was applied in performance evaluation. The experimental results demonstrated that the proposed model produced satisfying results and could be applicable in 3D facial verification systems. Furthermore, the verification rates proved that the 3D faces achieved from the proposed model enhanced the performance of the 3D verification process. Full article
(This article belongs to the Special Issue Recent Advances in Biometrics and its Applications)
Open AccessFeature PaperReview
Biologically-Inspired Computational Neural Mechanism for Human Action/activity Recognition: A Review
Electronics 2019, 8(10), 1169; https://doi.org/10.3390/electronics8101169 (registering DOI) - 15 Oct 2019
Abstract
Theoretical neuroscience investigation shows valuable information on the mechanism for recognizing the biological movements in the mammalian visual system. This involves many different fields of researches such as psychological, neurophysiology, neuro-psychological, computer vision, and artificial intelligence (AI). The research on these areas provided [...] Read more.
Theoretical neuroscience investigation shows valuable information on the mechanism for recognizing the biological movements in the mammalian visual system. This involves many different fields of researches such as psychological, neurophysiology, neuro-psychological, computer vision, and artificial intelligence (AI). The research on these areas provided massive information and plausible computational models. Here, a review on this subject is presented. This paper describes different perspective to look at this task including action perception, computational and knowledge based modeling, psychological, and neuroscience approaches. Full article
Open AccessArticle
Droop Control in DQ Coordinates for Fixed Frequency Inverter-Based AC Microgrids
Electronics 2019, 8(10), 1168; https://doi.org/10.3390/electronics8101168 (registering DOI) - 15 Oct 2019
Abstract
This paper presents a proof-of-concept for a novel dq droop control technique that applies DC droop control methods to fixed frequency inverter-based AC microgrids using the dq0 transformation. Microgrids are usually composed of distributed generation units (DGUs) that are electronically coupled to each [...] Read more.
This paper presents a proof-of-concept for a novel dq droop control technique that applies DC droop control methods to fixed frequency inverter-based AC microgrids using the dq0 transformation. Microgrids are usually composed of distributed generation units (DGUs) that are electronically coupled to each other through power converters. An inherent property of inverter-based microgrids is that, unlike microgrids with spinning machines, the frequency of the parallel-connected DGUs is a global variable independent from the output power since the inverters can control the output waveform frequency with a high level of precision. Therefore, conventional droop control methods that distort the system frequency are not suitable for microgrids operating at a fixed frequency. It is shown that the proposed distributed droop control allows accurate sharing of the active and reactive power without altering the microgrid frequency. The simulation and hardware-in-the-loop (HIL) results are presented to demonstrate the efficacy of the proposed droop control. Indeed, following a load change, the dq droop controller was able to share both active and reactive power between the DGUs, whereas maintaining the microgrid frequency deviation at 0% and the bus voltage deviations below 6% of their respective nominal values. Full article
(This article belongs to the Special Issue Control of Microgrids)
Open AccessArticle
False Positive Decremented Research for Fire and Smoke Detection in Surveillance Camera using Spatial and Temporal Features Based on Deep Learning
Electronics 2019, 8(10), 1167; https://doi.org/10.3390/electronics8101167 (registering DOI) - 15 Oct 2019
Abstract
Fire must be extinguished early, as it leads to economic losses and losses of precious lives. Vision-based methods have many difficulties in algorithm research due to the atypical nature fire flame and smoke. In this study, we introduce a novel smoke detection algorithm [...] Read more.
Fire must be extinguished early, as it leads to economic losses and losses of precious lives. Vision-based methods have many difficulties in algorithm research due to the atypical nature fire flame and smoke. In this study, we introduce a novel smoke detection algorithm that reduces false positive detection using spatial and temporal features based on deep learning from factory installed surveillance cameras. First, we calculated the global frame similarity and mean square error (MSE) to detect the moving of fire flame and smoke from input surveillance cameras. Second, we extracted the fire flame and smoke candidate area using the deep learning algorithm (Faster Region-based Convolutional Network (R-CNN)). Third, the final fire flame and smoke area was decided by local spatial and temporal information: frame difference, color, similarity, wavelet transform, coefficient of variation, and MSE. This research proposed a new algorithm using global and local frame features, which is well presented object information to reduce false positive based on the deep learning method. Experimental results show that the false positive detection of the proposed algorithm was reduced to about 99.9% in maintaining the smoke and fire detection performance. It was confirmed that the proposed method has excellent false detection performance. Full article
Open AccessFeature PaperArticle
SLEC: A Novel Serverless RFID Authentication Protocol Based on Elliptic Curve Cryptography
Electronics 2019, 8(10), 1166; https://doi.org/10.3390/electronics8101166 (registering DOI) - 15 Oct 2019
Abstract
Internet of Things (IoT) is a new paradigm that has been evolving into the wireless sensor networks to expand the scope of networked devices (or things). This evolution drives communication engineers to design secure and reliable communication at a low cost for many [...] Read more.
Internet of Things (IoT) is a new paradigm that has been evolving into the wireless sensor networks to expand the scope of networked devices (or things). This evolution drives communication engineers to design secure and reliable communication at a low cost for many network applications such as radio frequency identification (RFID). In the RFID system, servers, readers, and tags communicate wirelessly. Therefore, mutual authentication is necessary to ensure secure communication. Normally, a central server supports the authentication of readers and tags by distributing and managing the credentials. Recent lightweight RFID authentication protocols have been proposed to satisfy the security features of RFID networks. Using a serverless RFID system is an alternative solution to using a central server. In this model, both the reader and the tag perform mutual authentication without the need for the central server. However, many security challenges arise from implementing lightweight authentication protocols in serverless RFID systems. We propose a new secure serverless RFID authentication protocol based on the famous elliptic curve cryptography (ECC). The protocol also maintains the confidentiality and privacy of the messages, tag information, and location. Although most of the current serverless protocols assume secure channels in the setup phase, we assume an insecure environment during the setup phase between the servers, readers, and tags. We ensure that the credentials can be renewed by any checkpoint server in the mobile RFID network. Thus, we implement ECC in the setup phase (renewal phase), to transmit and store the communication credentials of the server to multiple readers so that the tags can perform the mutual authentication successfully while far from the server. The proposed protocol is compared with other serverless frameworks proposed in the literature in terms of computation cost and attacks resistance. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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Open AccessArticle
Expert Finding Considering Dynamic Profiles and Trust in Social Networks
Electronics 2019, 8(10), 1165; https://doi.org/10.3390/electronics8101165 (registering DOI) - 15 Oct 2019
Abstract
Recently, social network services that express individual opinions and thoughts have been significantly developed. As unreliable information is generated and shared by arbitrary users in social network services, many studies have been conducted to find users who provide reliable and professional information. In [...] Read more.
Recently, social network services that express individual opinions and thoughts have been significantly developed. As unreliable information is generated and shared by arbitrary users in social network services, many studies have been conducted to find users who provide reliable and professional information. In this paper, we propose an expert finding scheme to discover users who can answer users’ questions professionally in social network services. We use a dynamic profile to extract the user’s latest interest through an analysis of the user’s recent activity. To improve the accuracy of the expert finding results, we consider the user trust and response quality. We conduct a performance evaluation with the existing schemes through various experiments to verify the superiority of the proposed scheme. Full article
(This article belongs to the Special Issue Data Analysis in Intelligent Communication Systems)
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Open AccessArticle
Resonant Tunneling Diode (RTD) Terahertz Active Transmission Line Oscillator with Graphene-Plasma Wave and Two Graphene Antennas
Electronics 2019, 8(10), 1164; https://doi.org/10.3390/electronics8101164 - 14 Oct 2019
Viewed by 138
Abstract
This study describes the design of a resonant tunneling diode (RTD) oscillator (RTD oscillator) with a RTD-gated-graphene-2DEF (two dimensional electron fluid) and demonstrates the functioning of this RTD oscillator through a transmission line simulation model. Impedance of the RTD oscillator changes periodically when [...] Read more.
This study describes the design of a resonant tunneling diode (RTD) oscillator (RTD oscillator) with a RTD-gated-graphene-2DEF (two dimensional electron fluid) and demonstrates the functioning of this RTD oscillator through a transmission line simulation model. Impedance of the RTD oscillator changes periodically when physical dimension of the device is of considerable fraction of the electrical wavelength. As long as impedance matching is achieved, the oscillation frequency is not limited by the size of the device. An RTD oscillator with a graphene film and negative differential resistance (NDR) will produce power amplification. The positive electrode of the DC power supply is modified and designed as an antenna. So, the reflected power can also be radiated to increase RTD oscillator output power. The output analysis shows that through the optimization of the antenna structure, it is possible to increase the RTD oscillator output to 22 mW at 1.9 THz and 20 mW at 6.1 THz respectively. Furthermore, the RTD oscillator has the potential to oscillate at 50 THz with a matching antenna. Full article
(This article belongs to the Section Microwave and Wireless Communications)
Open AccessArticle
Deductive Verification Method of Real-Time Safety Properties for Embedded Assembly Programs
Electronics 2019, 8(10), 1163; https://doi.org/10.3390/electronics8101163 - 14 Oct 2019
Viewed by 104
Abstract
It is important to verify both the correctness and real-time properties of embedded systems. However, as practical computer programs are represented by infinite state transition systems, specifying and verifying a computer program is difficult. Real-time properties are also important for embedded programs, but [...] Read more.
It is important to verify both the correctness and real-time properties of embedded systems. However, as practical computer programs are represented by infinite state transition systems, specifying and verifying a computer program is difficult. Real-time properties are also important for embedded programs, but verifying the real-time properties of an embedded program is difficult. In this paper, we focus on verifying an embedded assembly program, in order to verify the real-time safety properties. We propose a deductive verification method to verify real-time safety properties, based on discrete time, as follows: (1) First, we construct a timed computational model including the execution time from the assembly program. We can specify an infinite state transition system including the execution time of the timed computational model. (2) Next, we verify whether a timed computational model satisfies RTLTL (Real-Time Linear Temporal Logic) formulas by deductive verification. We can specify real-time properties by RTLTL. By our proposed methods, we are able to achieve verification of the real-time safety properties of an embedded program. Full article
(This article belongs to the Section Computer Science & Engineering)
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Open AccessArticle
Building Scalable and Secure Multicast Delivery Infrastructure in a Local Area Network
Electronics 2019, 8(10), 1162; https://doi.org/10.3390/electronics8101162 - 14 Oct 2019
Viewed by 141
Abstract
Internet Protocol (IP) multicasting is a method for one-to-many and many-to-many communication between hosts in an IP network. This communication happens in a real-time synchronous fashion. It is a useful mechanism for distributing management data in a Local Area Network (LAN). Management data [...] Read more.
Internet Protocol (IP) multicasting is a method for one-to-many and many-to-many communication between hosts in an IP network. This communication happens in a real-time synchronous fashion. It is a useful mechanism for distributing management data in a Local Area Network (LAN). Management data includes frequent updating of host Operating System (OS), security patches, OS update for network hardware, new configuration updates, etc. In the absence of any admission control or a source identification, any host with malicious intent can disseminate malicious codes or rootkits exploiting the underlying multicast framework. Routing protocols like RIPv2 and OSPF use a certain form of authentication to exchange routing information with their peer routers. However, their authentication and the distribution of routing information in its present form has several security and performance-related issues. Motivated through these problems, in this paper, we propose an efficient and scalable multicast architecture for distributing management and routing information in a LAN. We use Core-based Tree (CBT) for constructing the multicast delivery tree and the pseudo identity-based encryption of the underlying cryptosystem. We also demonstrate that our proposed multicast architecture is immune to a number of popular attacks. Full article
(This article belongs to the Section Networks)
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Open AccessArticle
A Subthreshold Bootstrapped SAPTL-Based Adder Design
Electronics 2019, 8(10), 1161; https://doi.org/10.3390/electronics8101161 - 12 Oct 2019
Viewed by 207
Abstract
This paper proposes a 16 bit subthreshold adder design using bootstrapped sense amplifier-based pass transistor logic (bootstrapped SAPTL) to overcome serious performance degradation and enhance the immunity to process variations in the subthreshold region. Through employing a bootstrapped sense amplifier including a voltage [...] Read more.
This paper proposes a 16 bit subthreshold adder design using bootstrapped sense amplifier-based pass transistor logic (bootstrapped SAPTL) to overcome serious performance degradation and enhance the immunity to process variations in the subthreshold region. Through employing a bootstrapped sense amplifier including a voltage boosting part and adopting an adder architecture based on bootstrapped SAPTL, significant improvements in performance and energy efficiency can be achieved. A case study of 16 bit adders in SMIC 130 nm technology demonstrated that the proposed adder outperformed other works in terms of performance, energy consumption, and energy efficiency. Furthermore, the statistical results of the Monte Carlo analysis proved the proposed adder’s significant enhancement of robustness against process and temperature variations. At 0.3 V (TT corner, 25 °C), the proposed 16 bit adder achieved improvements of 72% in performance and 8% in energy savings, as well as a 74% reduction in energy-delay production as compared with the current design. Full article
(This article belongs to the Section Microelectronics and Optoelectronics)
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Open AccessArticle
Management of Multiple-Transmitter Multiple-Receiver Wireless Power Transfer Systems Using Improved Current Distribution Control Strategy
Electronics 2019, 8(10), 1160; https://doi.org/10.3390/electronics8101160 - 12 Oct 2019
Viewed by 193
Abstract
For high-power single-transmitter single-receiver wireless power transfer (STSRWPT) systems, the coils suffer from high voltage and current stresses. With increased power requirements, the coils become bottlenecks for power flow. To increase the power level, multiple-transmitter multiple-receiver wireless power transfer (MTMRWPT) systems with parallel [...] Read more.
For high-power single-transmitter single-receiver wireless power transfer (STSRWPT) systems, the coils suffer from high voltage and current stresses. With increased power requirements, the coils become bottlenecks for power flow. To increase the power level, multiple-transmitter multiple-receiver wireless power transfer (MTMRWPT) systems with parallel circuits are developed that reduce the voltage and current stresses on the coils and improve power-handling capability. Firstly, an improved current distribution (ICD) control strategy is developed to simultaneously achieve high transfer efficiency, balanced current distribution and constant output voltage. Secondly, it is further shown that the ICD control strategy has the advantage that the currents at the transmitter coils are balanced and it reduces the control complexity simultaneously. Thirdly, an asynchronous particle swarm optimization (APSO) algorithm is applied to the ICD control strategy to verify the feasibility of the proposed control strategy. Lastly, a two-transmitter two-receiver wireless power transfer (WPT) system based on the ICD control strategy is proved to obtain an efficiency of more than 89.1% and provides the target output voltage 20 V with balanced current distribution. Full article
(This article belongs to the Section Power Electronics)
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Open AccessArticle
Memory Optimization for Bit-Vector-Based Packet Classification on FPGA
Electronics 2019, 8(10), 1159; https://doi.org/10.3390/electronics8101159 - 12 Oct 2019
Viewed by 171
Abstract
High-performance packet classification algorithms have been widely studied during the past decade. Bit-Vector-based algorithms proposed for FPGA can achieve very high throughput by decomposing rules delicately. However, the relatively large memory resources consumption severely hinders applications of the algorithms extensively. It is noteworthy [...] Read more.
High-performance packet classification algorithms have been widely studied during the past decade. Bit-Vector-based algorithms proposed for FPGA can achieve very high throughput by decomposing rules delicately. However, the relatively large memory resources consumption severely hinders applications of the algorithms extensively. It is noteworthy that, in the Bit-Vector-based algorithms, stringent memory resources in FPGA are wasted to store relatively plenty of useless wildcards in the rules. We thus present a memory-optimized packet classification scheme named WeeBV to eliminate the memory occupied by the wildcards. WeeBV consists of a heterogeneous two-dimensional lookup pipeline and an optimized heuristic algorithm for searching all the wildcard positions that can be removed. It can achieve a significant reduction in memory resources without compromising the high throughput of the original Bit-Vector-based algorithms. We implement WeeBV and evaluate its performance by simulation and FPGA prototype. Experimental results show that our approach can save 37% and 41% memory consumption on average for synthetic 5-tuple rules and OpenFlow rules respectively. Full article
(This article belongs to the Special Issue New Applications and Architectures Based on FPGA/SoC)
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Open AccessArticle
Probabilistic Evaluation and Improvement Measures of Power Supply Capability Considering Massive EV Integration
Electronics 2019, 8(10), 1158; https://doi.org/10.3390/electronics8101158 - 12 Oct 2019
Viewed by 105
Abstract
Massive electric vehicle (EV) integration has been an inevitable trend for future power distribution networks. However, the spatial-temporal randomness of EV charging behavior may cause insufficiency of power supply capability. This paper simulates the charging loads with massive EV integration, proposes a probabilistic [...] Read more.
Massive electric vehicle (EV) integration has been an inevitable trend for future power distribution networks. However, the spatial-temporal randomness of EV charging behavior may cause insufficiency of power supply capability. This paper simulates the charging loads with massive EV integration, proposes a probabilistic evaluation index to evaluate the probability of insufficient power supply capability, and gives improvement measures for power distribution networks without hardware upgrading. First, the spatial-temporal distribution of EV charging loads is simulated via Monte Carlo method, which particularly divides EVs into three categories, private cars, buses, and taxis. Then, aggregated with conventional loads, total supply capacity of a power distribution network can be calculated on different time periods. Second, for the uncertainty of EV charging loads both in time and space, a probabilistic evaluation index is addressed to evaluate the probability of power supply capability insufficiency. After that, several improvement measures of the charging strategy are given to relieve the insufficiency of power supply capability. Finally, taking the simplified distribution network of a typical power supply mode in China’s Fujian province as an example, three scenarios with different vehicle quantities and parameters are designed, and the effectiveness of the evaluation index and improvement measures proposed are identified. The results can provide evidences for constraining EV charging behaviors with massive integration. Full article
(This article belongs to the Special Issue Prospects for Integrating Electric Vehicles into Power Systems)
Open AccessArticle
High-CMRR Low-Noise Fully Integrated Front-End for EEG Acquisition Systems
Electronics 2019, 8(10), 1157; https://doi.org/10.3390/electronics8101157 - 12 Oct 2019
Viewed by 103
Abstract
We present in this paper a fully integrated low-noise high common-mode rejection ratio (CMRR) logarithmic programmable gain amplifier (LPGA) and chopped LPGA circuits for EEG acquisition systems. The proposed LPGA is based on a rail-to-rail true logarithmic amplifier (TLA) stage. The high CMRR [...] Read more.
We present in this paper a fully integrated low-noise high common-mode rejection ratio (CMRR) logarithmic programmable gain amplifier (LPGA) and chopped LPGA circuits for EEG acquisition systems. The proposed LPGA is based on a rail-to-rail true logarithmic amplifier (TLA) stage. The high CMRR achieved in this work is a result of cascading three amplification stages to construct the LPGA in addition to the lower common-mode gain of the proposed logarithmic amplification topology. In addition, the 1 / f noise and the inherent DC offset voltage of the input transistors are reduced using a chopper stabilization technique. The CMOS 180 nm standard technology is used to implement the circuits. Experimental results for the integrated LPGA show a CMRR of 140 dB, a differential gain of 37 dB, an input-referred noise of 0.754 μ Vrms, a 189 μ W power consumption from 1.8 V power supply and occupies an active area of 0.4 mm 2 . Full article
(This article belongs to the Special Issue Nanoscale CMOS Technologies)
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Open AccessFeature PaperArticle
Design of a Wide-Band Voltage-Controlled Ring Oscillator Implemented in 180 nm CMOS Technology
Electronics 2019, 8(10), 1156; https://doi.org/10.3390/electronics8101156 - 12 Oct 2019
Viewed by 141
Abstract
The design of a wide-band voltage-controlled oscillator (VCO) modified as a VCO with programmable tail currents is introduced herein. The VCO is implemented by using CMOS current-mode logic stages, which are based on differential pairs that are connected in a ring topology. SPICE [...] Read more.
The design of a wide-band voltage-controlled oscillator (VCO) modified as a VCO with programmable tail currents is introduced herein. The VCO is implemented by using CMOS current-mode logic stages, which are based on differential pairs that are connected in a ring topology. SPICE simulation results show that the VCO operates within the frequency ranges of 2.65–5.65 GHz, and when it is modified, the VCO with programmable tail currents operates between 1.38 GHz and 4.72 GHz. The design of the CMOS differential stage is detailed along with the symbolic approximation of its dominant pole, which is varied to increase the frequency response in order to achieve a higher oscillation frequency when implementing the ring oscillator structure. The layout of the VCO is described and pre- and post-layout simulations are provided, which are in good agreement using CMOS technology of 180 nm. Finally, process, voltage and temperature variations are performed to guarantee robustness of the designed CMOS ring oscillator. Full article
(This article belongs to the Section Circuit and Signal Processing)
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Open AccessFeature PaperArticle
Comparison of Measurement Methods of LV Grid Access Impedance in the Frequency Range Assigned to Nb‑Plc Technologies
Electronics 2019, 8(10), 1155; https://doi.org/10.3390/electronics8101155 - 12 Oct 2019
Viewed by 126
Abstract
The paper presents and evaluates three advanced methods for the characterization of the low-voltage (LV) grid access impedance for the frequency range assigned to Narrow Band-Power Line Communications (NB-PLC): 9 kHz to 500 kHz. This study responds to the recent demand from both [...] Read more.
The paper presents and evaluates three advanced methods for the characterization of the low-voltage (LV) grid access impedance for the frequency range assigned to Narrow Band-Power Line Communications (NB-PLC): 9 kHz to 500 kHz. This study responds to the recent demand from both regulatory bodies and Distribution System Operators about the need for accurate and validated methods for this frequency band, due to the limited knowledge of the impedance values in the electrical grid and their influence on NB-PLC transmission channels. In this paper, the results of a collaborative work to develop different proposals to overcome the challenges for the proper characterization of the frequency and time-varying grid impedance, from different theoretical approaches, are presented. The methods are compared in a controlled and isolated scenario: the impedance characterization of passive filters. Then, the results are validated two-fold: first, against theoretical simulations, based on the schematics provided by the manufacturer, and second, against the measurement results of a precision impedance meter, used as a reference of accuracy. The results demonstrate a high degree of precision of the three proposals to characterize the access impedance of the LV grid. Full article
(This article belongs to the Special Issue Advances of Power Line Communication (PLC))
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Open AccessArticle
Design and Construction of a Cost-Effective Didactic Robotic Arm for Playing Chess, Using an Artificial Vision System
Electronics 2019, 8(10), 1154; https://doi.org/10.3390/electronics8101154 - 12 Oct 2019
Viewed by 160
Abstract
This paper presents the design and construction of a robotic arm that plays chess against a human opponent, based on an artificial vision system. The mechanical design was an adaptation of the robotic arm proposed by the rapid prototyping laboratory FabLab RUC (Fabrication [...] Read more.
This paper presents the design and construction of a robotic arm that plays chess against a human opponent, based on an artificial vision system. The mechanical design was an adaptation of the robotic arm proposed by the rapid prototyping laboratory FabLab RUC (Fabrication Laboratory of the University of Roskilde). Using the software Solidworks, a gripper with 4 joints was designed. An artificial vision system was developed for detecting the corners of the squares on a chessboard and performing image segmentation. Then, an image recognition model was trained using convolutional neural networks to detect the movements of pieces on the board. An image-based visual servoing system was designed using the Kanade–Lucas–Tomasi method, in order to locate the manipulator. Additionally, an Arduino development board was programmed to control and receive information from the robotic arm using Gcode commands. Results show that with the Stockfish chess game engine, the system is able to make game decisions and manipulate the pieces on the board. In this way, it was possible to implement a didactic robotic arm as a relevant application in data processing and decision-making for programmable automatons. Full article
(This article belongs to the Section Artificial Intelligence)
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Open AccessArticle
Airborne LiDAR Point Cloud Filtering by a Multilevel Adaptive Filter Based on Morphological Reconstruction and Thin Plate Spline Interpolation
Electronics 2019, 8(10), 1153; https://doi.org/10.3390/electronics8101153 - 12 Oct 2019
Viewed by 114
Abstract
Point cloud filtering is a crucial step in most airborne light detection and ranging (LiDAR) applications. Many filtering algorithms have been proposed, but the filtering effect has some limitations in complex environments. To improve the filtering effect in complex terrain, a multilevel adaptive [...] Read more.
Point cloud filtering is a crucial step in most airborne light detection and ranging (LiDAR) applications. Many filtering algorithms have been proposed, but the filtering effect has some limitations in complex environments. To improve the filtering effect in complex terrain, a multilevel adaptive filter (MAF) combining morphological reconstruction and thin plate spline (TPS) interpolation is proposed. The digital elevation model (DEM) generated in each iteration is used as the marker image for morphological reconstruction to extract ground pixels, and an adaptive residual threshold is achieved by using terrain gradient as a compensation. The benchmark dataset provided by the International Society for Photogrammetry and Remote Sensing (ISPRS) and another LiDAR dataset in northwestern China were used to evaluate the filtering performance of MAF. For the ISPRS benchmark dataset, MAF obtained the lowest average total error (3.72%) and highest average kappa coefficient (87.16%) compared with eight classic filtering algorithms. For the dataset in northwestern China, the DEM generated from the filtering result of MAF obtained higher accuracy than the filtering result of TerraScan. Overall, the MAF achieved promising results without considering the selection of filtering window, which may enhance the robustness and applicability of the algorithm in different environments. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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Open AccessFeature PaperArticle
Multi-Sensor Accurate Forklift Location and Tracking Simulation in Industrial Indoor Environments
Electronics 2019, 8(10), 1152; https://doi.org/10.3390/electronics8101152 - 12 Oct 2019
Viewed by 144
Abstract
Location and tracking needs are becoming more prominent in industrial environments nowadays. Process optimization, traceability or safety are some of the topics where a positioning system can operate to improve and increase the productivity of a factory or warehouse. Among the different options, [...] Read more.
Location and tracking needs are becoming more prominent in industrial environments nowadays. Process optimization, traceability or safety are some of the topics where a positioning system can operate to improve and increase the productivity of a factory or warehouse. Among the different options, solutions based on ultra-wideband (UWB) have emerged during recent years as a good choice to obtain highly accurate estimations in indoor scenarios. However, the typical harsh wireless channel conditions found inside industrial environments, together with interferences caused by workers and machinery, constitute a challenge for this kind of system. This paper describes a real industrial problem (location and tracking of forklift trucks) that requires precise internal positioning and presents a study on the feasibility of meeting this challenge using UWB technology. To this end, a simulator of this technology was created based on UWB measurements from a set of real sensors. This simulator was used together with a location algorithm and a physical model of the forklift to obtain estimations of position in different scenarios with different obstacles. Together with the simulated UWB sensor, an additional inertial sensor and optical sensor were modeled in order to test its effect on supporting the location based on UWB. All the software created for this work is published under an open-source license and is publicly available. Full article
(This article belongs to the Special Issue Indoor Positioning Techniques)
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Open AccessArticle
Real-Time Object Detection in Remote Sensing Images Based on Visual Perception and Memory Reasoning
Electronics 2019, 8(10), 1151; https://doi.org/10.3390/electronics8101151 - 11 Oct 2019
Viewed by 152
Abstract
Aiming at the real-time detection of multiple objects and micro-objects in large-scene remote sensing images, a cascaded convolutional neural network real-time object-detection framework for remote sensing images is proposed, which integrates visual perception and convolutional memory network reasoning. The detection framework is composed [...] Read more.
Aiming at the real-time detection of multiple objects and micro-objects in large-scene remote sensing images, a cascaded convolutional neural network real-time object-detection framework for remote sensing images is proposed, which integrates visual perception and convolutional memory network reasoning. The detection framework is composed of two fully convolutional networks, namely, the strengthened object self-attention pre-screening fully convolutional network (SOSA-FCN) and the object accurate detection fully convolutional network (AD-FCN). SOSA-FCN introduces a self-attention module to extract attention feature maps and constructs a depth feature pyramid to optimize the attention feature maps by combining convolutional long-term and short-term memory networks. It guides the acquisition of potential sub-regions of the object in the scene, reduces the computational complexity, and enhances the network’s ability to extract multi-scale object features. It adapts to the complex background and small object characteristics of a large-scene remote sensing image. In AD-FCN, the object mask and object orientation estimation layer are designed to achieve fine positioning of candidate frames. The performance of the proposed algorithm is compared with that of other advanced methods on NWPU_VHR-10, DOTA, UCAS-AOD, and other open datasets. The experimental results show that the proposed algorithm significantly improves the efficiency of object detection while ensuring detection accuracy and has high adaptability. It has extensive engineering application prospects. Full article
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Open AccessArticle
Platform-Based Business Models: Insights from an Emerging Ai-Enabled Smart Building Ecosystem
Electronics 2019, 8(10), 1150; https://doi.org/10.3390/electronics8101150 - 11 Oct 2019
Viewed by 116
Abstract
Artificial intelligence (AI) is emerging to become a highly potential enabling technology for smart buildings. However, the development of AI applications quite often follows a traditional, closed, and product-oriented approach. This study aims to introduce the platform model and ecosystem thinking to the [...] Read more.
Artificial intelligence (AI) is emerging to become a highly potential enabling technology for smart buildings. However, the development of AI applications quite often follows a traditional, closed, and product-oriented approach. This study aims to introduce the platform model and ecosystem thinking to the development of AI-enabled smart buildings. The study identifies the needs for a user-oriented digital service ecosystem and business model in the smart building sector in Finland, which aimed to facilitate the launch of scalable businesses and an experiential and dynamic business ecosystem. A multi-method, interpretive case study was applied in the focal ecosystem, with the leading real estate and facility management operators in Northern Europe as part of a Finnish national innovation project. Our results propose an extended comprehensive framework of the 5C ecosystemic model (Connection, Content, Computation, Context, and Commerce) and the possible paths of ecosystem players in the domain of smart building and smart built environment, both theoretically and empirically. The platform-oriented business models are missing, yet desired, by the ecosystem actors. The value chain and ecosystem platforms imply the quest for new (platform) models. Finally, our research discusses the need for new value-chain- and ecosystem-oriented AI development and big data platforms in the future. Full article
Open AccessArticle
A 6-Bit Ku Band Digital Step Attenuator with Low Phase Variation in 0.13-μm SiGe BiCMOS
Electronics 2019, 8(10), 1149; https://doi.org/10.3390/electronics8101149 - 11 Oct 2019
Viewed by 102
Abstract
A 6-bit Ku band digital step attenuator with low phase variation is presented in this paper. The attenuator is designed with 0.13-μm SiGe BiCMOS process technology using triple well isolation N-Metal-Oxide-Semiconductor (TWNMOS) and through-silicon-via (TSV). TWNMOS is mainly used to improve the performance [...] Read more.
A 6-bit Ku band digital step attenuator with low phase variation is presented in this paper. The attenuator is designed with 0.13-μm SiGe BiCMOS process technology using triple well isolation N-Metal-Oxide-Semiconductor (TWNMOS) and through-silicon-via (TSV). TWNMOS is mainly used to improve the performance of switches and reduce the insertion loss (IL). TSV is utilized to provide approximately ideal global current ground plane with low impedance for the attenuator. In addition, substrate floating technique and new capacitance compensation technique are adopted in the attenuator to improve the linearity and decrease the phase variation. The measured results show that the attenuator IL is 6.99–9.33 dB; the maximum relative attenuation is 31.87–30.31 dB with 0.5-dB step (64 states), the root mean square (RMS) for the amplitude error is 0.58–0.36 dB and the phase error RMS is 2.06–3.46° in the 12–17 GHz frequency range. The total chip area is 1 × 0.9 mm2. Full article
(This article belongs to the Special Issue Microwave Integrated Circuits Design and Application)
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Open AccessArticle
A High Channel Consistency Subarray of Plane-Wave Generators for 5G Base Station OTA Testing
Electronics 2019, 8(10), 1148; https://doi.org/10.3390/electronics8101148 - 11 Oct 2019
Viewed by 107
Abstract
A high channel consistency subarray of plane-wave generators (PWG) is described for fifth-generation (5G) base station (BS) over-the-air (OTA) testing. Firstly, the variation of the near field radiation characteristics of the subarray based on the feed amplitude and phase errors of the traditional [...] Read more.
A high channel consistency subarray of plane-wave generators (PWG) is described for fifth-generation (5G) base station (BS) over-the-air (OTA) testing. Firstly, the variation of the near field radiation characteristics of the subarray based on the feed amplitude and phase errors of the traditional power divider network is analyzed. The recommended amplitude and phase errors between channels are given. After that, a novel subarray which combines four pyramidal horn antennas and a compact 1:4 waveguide power divider is designed. The optimized perfectly symmetrical zigzag waveguide transmission lines are used to realize consistent power allocation among antenna elements. No intermediate pins are employed, which avoids the significant deterioration of channel consistency caused by assembly errors. The size of the subarray is 4.89 λ0 × 4.97 λ0 × 1.23 λ00 is the working wavelength corresponding to the subarray center frequency at 3.5 GHz). The VSWR < 1.5 impedance bandwidth covers 3.4 GHz to 3.6 GHz. The amplitude difference between the four elements of the subarray is less than 0.5 dB, and the phase difference is less than 3°. The simulated and measured results agree well in this design. Full article
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Open AccessArticle
A High-Resolution Measurement System Designed for Semiconductor Microcalorimetry Sensors
Electronics 2019, 8(10), 1147; https://doi.org/10.3390/electronics8101147 - 11 Oct 2019
Viewed by 127
Abstract
The quality of measurements of non-electrical quantities not only depends on the sensor but also on the electronic system that is used for the conversion of the electrical signals to a digital form. Many research papers on the subject analyse the properties and [...] Read more.
The quality of measurements of non-electrical quantities not only depends on the sensor but also on the electronic system that is used for the conversion of the electrical signals to a digital form. Many research papers on the subject analyse the properties and characteristics of the sensors in detail but omit the properties of the instruments that are used to measure the characteristics. This paper concentrates on the problems concerning the design of an instrument for generating control signals and measuring the output signals of a semiconductor sensor. The measurement instrument is designed for a commercial heat flow microcalorimeter that is able to measure heat flows at the level of several µW. The novelty of this paper is the analysis of some of the undocumented properties of the sensor and the interactions between its components. The design of the instrument makes it possible to correctly measure the output signals of a microcalorimeter without the influence of the described effects. The added value of this paper is a detailed analysis of the resolution of the system and the factors that may affect it. The remarks contained in the paper can be useful for designers of other instruments that are designed for measuring non-electrical quantities. Full article
(This article belongs to the Section Circuit and Signal Processing)
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Open AccessFeature PaperArticle
A Reconfigurable Radio-Frequency Converter IC in 0.18 µm CMOS
Electronics 2019, 8(10), 1146; https://doi.org/10.3390/electronics8101146 - 10 Oct 2019
Viewed by 167
Abstract
This work presents a reconfigurable RF converter for DVB-T television applications using triple-play over GPON. The system takes the DVB-T input, a wavelength division multiplexing (WDM) signal with spectral inversion in the range from 47 M Hz –1000 M Hz , up-converts its [...] Read more.
This work presents a reconfigurable RF converter for DVB-T television applications using triple-play over GPON. The system takes the DVB-T input, a wavelength division multiplexing (WDM) signal with spectral inversion in the range from 47 M Hz –1000 M Hz , up-converts its frequency to the band-pass of a highly selective surface-acoustic wave (SAW) filter centered at 1 . 3 G Hz , and then down-converts it so that it is compatible with the antenna input of conventional television sets. The designed RF converter incorporates two pairs of frequency synthesizer and mixer, based, respectively, on an integer-N phase-locked loop (PLL) with two LC-tank VCOs with 128 coarse tuning bands in the range from 1.35 G Hz –2.7 G Hz , and a double-balanced Gilbert cell, modified for better impedance matching and improved linearity. It is fed with regulated supplies compensated in temperature and programmed by an I 2 C interface operating on five 16-bit registers. This work presents the experimental characterization of the whole system plus selected cells for stand-alone testing, which have been fabricated in a 0 . 18 m CMOS process. Full article
(This article belongs to the Section Microelectronics and Optoelectronics)
Open AccessFeature PaperArticle
Multi-Backup Beams for Instantaneous Link Recovery in mmWave Communications
Electronics 2019, 8(10), 1145; https://doi.org/10.3390/electronics8101145 - 10 Oct 2019
Viewed by 135
Abstract
In this paper, a novel link recover scheme is proposed for standalone (SA) millimeter wave communications. Once the main beam between the base station (BS) and the mobile station (MS) is blocked, then a bundle-beam is radiated that covers the spatial direction of [...] Read more.
In this paper, a novel link recover scheme is proposed for standalone (SA) millimeter wave communications. Once the main beam between the base station (BS) and the mobile station (MS) is blocked, then a bundle-beam is radiated that covers the spatial direction of the blocked beam. These beams are generated from an analog beamformer design that is composed of parallel adjacent antenna arrays to radiate multiple simultaneous beams, thus creating an analog beamformer of multiple beams. The proposed recovery scheme features instantaneous recovery times, without the need for beam scanning to search for alternative beam directions. Hence, the scheme features reduced recovery times and latencies, as opposed to existing methods. Full article
(This article belongs to the Special Issue Millimeter-Wave (mmWave) Communications)
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Open AccessArticle
A Fast Charging Balancing Circuit for LiFePO4 Battery
Electronics 2019, 8(10), 1144; https://doi.org/10.3390/electronics8101144 - 10 Oct 2019
Viewed by 142
Abstract
In this paper, a fast charging balancing circuit for LiFePO4 battery is proposed to address the voltage imbalanced problem of a lithium battery string. During the lithium battery string charging process, the occurrence of voltage imbalance will activate the fast balancing mechanism. [...] Read more.
In this paper, a fast charging balancing circuit for LiFePO4 battery is proposed to address the voltage imbalanced problem of a lithium battery string. During the lithium battery string charging process, the occurrence of voltage imbalance will activate the fast balancing mechanism. The proposed balancing circuit is composed of a bi-directional converter and the switch network. The purpose of bi-directional is that the energy can be delivered to the lowest voltage cell for charging mode. On the other hand, the energy stored in the magnetizing inductors of the transformer can be charged back to the higher voltage cell in recycling mode. This novel scheme includes the following features: (1) The odd-numbered and even-numbered cells in the string with the maximum differential voltage will be chosen for balancing process directly. In this topology, there is no need to store and deliver the energy through any intermediate or the extra storing components. That is, the energy loss can be saved to improve the efficiency, and the fast balancing technique can be achieved. (2) There is only one converter to complete the energy transfer for voltage balancing process. The concept makes the circuit structure much simpler. (3) The structure has bi-directional power flow and good electrical isolation features. (4) A single chip controller is applied to measure the voltage of each cell to achieve the fast balancing process effectively. At the end of the paper, the practical test of the proposed balancing method on LiFePO4 battery pack (28.8 V/2.5 Ah) is verified and implemented by the experimental results. Full article
(This article belongs to the Special Issue Power Converters in Power Electronics)
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Open AccessArticle
A Two-Module Linear Regulator with 3.9–10 V Input, 2.5 V Output, and 500 mA Load
Electronics 2019, 8(10), 1143; https://doi.org/10.3390/electronics8101143 - 10 Oct 2019
Viewed by 106
Abstract
A linear regulator with an input range of 3.9–10 V, 2.5 V output, and a maximal 500 mA load for use with battery systems was developed and presented here. The linear regulator featured two modules of a preregulator and a linear regulator core [...] Read more.
A linear regulator with an input range of 3.9–10 V, 2.5 V output, and a maximal 500 mA load for use with battery systems was developed and presented here. The linear regulator featured two modules of a preregulator and a linear regulator core circuit, offering minimized power dissipation and high-level stability. The preregulator delivered an internal power voltage of 3 V and supplied internal circuits including the second module (the linear regulator core). The preregulator fitted with an active, low-pass filter provided a low-noise reference voltage to the linear regulator core circuit. To ensure operational stability for the linear regulator, error amplifiers incorporating the Miller compensation technique and featuring a large slewing rate were employed in the two modules. The circuit was successfully implemented in a 0.25 µm, 5 V complementary metal-oxide semiconductor (CMOS) process featuring 20 V drain-extended MOS (DMOS)/bipolar high-voltage devices. The total silicon area, including all pads, was approximately 1.67 mm2. To reduce chip area, bipolar rather than DMOS transistors served as the power transistors. Measured results demonstrated that the designed linear regulator was able to operate at an input voltage ranging from 3.9 to 10 V and offer a maximum 500 mA load current with fixed 2.5 V output voltage. Full article
(This article belongs to the Section Microelectronics and Optoelectronics)
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Open AccessArticle
A Fast GMPPT Algorithm Based on PV Characteristic for Partial Shading Conditions
Electronics 2019, 8(10), 1142; https://doi.org/10.3390/electronics8101142 - 09 Oct 2019
Viewed by 176
Abstract
Photovoltaic (PV) modules experience some partial shading conditions (PSC) due to some various factors. In that kind of a condition, a few maximum power points (MPPs) possibly appear on the power-voltage (P-V) curve, which increases the tracking difficulties. It is known that maximum [...] Read more.
Photovoltaic (PV) modules experience some partial shading conditions (PSC) due to some various factors. In that kind of a condition, a few maximum power points (MPPs) possibly appear on the power-voltage (P-V) curve, which increases the tracking difficulties. It is known that maximum power point tracking (MPPT) may not be realized by hill climbing (HC) based conventional MPPT algorithms under PSCs. In this context, this paper presents a novel micro converter based algorithm that was developed by using P-V characteristics of PV modules. Unlike voltage or duty ratio scanning techniques, this paper introduces a new deciding method to determine the correct global MPP (GMPP) region. For this, the proposed method uses some duty ratios that were calculated corresponding to each MPP region. Thus, the initialization of duty ratio is done properly, which results in high tracking speed and accurate tracking of the GMPP. The other advantages of the proposed algorithm are structural simplicity, less computational burden, and ease of implementation with a basic microcontroller. The simulation results show that this algorithm has fast tracking capability and it manages to track GMPP for PSCs correctly, since it includes an artificial scanning procedure. Single ended primary inductance converter (SEPIC) is built in order to validate the proposed global maximum power point tracking (GMPPT) algorithm. The performance of the proposed GMPPT technique is verified by experimental studies. The results show that the proposed GMPPT technique is fast by up to five times than an adaptive full scanning strategy and improved IC algorithm. Furthermore, the proposed algorithm can be commercially used in micro converters, since it is compatible with small number of bypass diodes in a module. Full article
(This article belongs to the Special Issue Photovoltaic Systems for Sustainable Energy)
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Open AccessArticle
Design and Analysis of the Task Distribution Scheme of Express Center at the End of Modern Logistics
Electronics 2019, 8(10), 1141; https://doi.org/10.3390/electronics8101141 - 09 Oct 2019
Viewed by 142
Abstract
With the rise and improvement of artificial intelligence technology, the express delivery industry has become more intelligent. At the terminal of modern logistics, each dispatch center has hundreds of express mail deliveries to be dispatched every day, and the number of dispatchers is [...] Read more.
With the rise and improvement of artificial intelligence technology, the express delivery industry has become more intelligent. At the terminal of modern logistics, each dispatch center has hundreds of express mail deliveries to be dispatched every day, and the number of dispatchers is far less than the number of express mail deliveries. How to assign scientific tasks to each courier dispatch is the main target of this paper. The purpose is to make the number of tasks between the various couriers in the express center roughly the same in each cycle, so that there is a more balanced income between the couriers. In the simulation experiment, the delivery addresses are clustered according to the balanced k-means algorithm. Then, the ant colony algorithm is used to plan the delivery order of the express items in each class. Then, the time cost model is established according to the delivery distance of the express items in each class and the delivery mode of the express items to calculate the delivery time cost. Through a large amount of experimental data, the standard deviation of delivery time cost of each courier gradually decreases and tends to stabilize, which suggests that this method has a good effect on the dispatching task assignment of the express center. It can effectively make the delivery workload between the distributors roughly the same, and improve the delivery efficiency of the courier, save energy, and promote sustainable development. Full article
(This article belongs to the Special Issue Data Analysis in Intelligent Communication Systems)
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