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Electronics, Volume 8, Issue 7 (July 2019) – 100 articles

Cover Story (view full-size image): The vehicular ad hoc network (VANET) is one major aspect of intelligent transportation systems (ITSs). VANETs have been used to improve driver and passenger safety on roads and highways. Therefore, the improvement of road safety consciousness is desired in VANETs. Sporadic message transmission causes overutilization of RSU or CPU as a result of hybrid DoS attacks (HDSAs) encountered in the vulnerable environment of VANET deployment. Most existing methods that have been used do not provide vehicular fog computing (VFC), hybrid optimization algorithms (HOA), or key distribution establishment (KDE). However, these combined methods have the tendency to provide swarm intelligence and enough storage for the trustworthiness computation of safety messages. View this paper.
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Open AccessArticle
A Charge-Sharing-Based Two-Phase Charging Scheme for Zero-Crossing-Based Integrator Circuits
Electronics 2019, 8(7), 821; https://doi.org/10.3390/electronics8070821 - 23 Jul 2019
Cited by 3 | Viewed by 1372
Abstract
As an effort to improve the energy efficiency of switched-capacitor circuits, zero-crossing- based integrators (ZCBI) that consist of zero-crossing detectors and charging circuits have been proposed. To break the trade-off between accuracy and speed, ZCBI typically employs a two-phase charging scheme that relies [...] Read more.
As an effort to improve the energy efficiency of switched-capacitor circuits, zero-crossing- based integrators (ZCBI) that consist of zero-crossing detectors and charging circuits have been proposed. To break the trade-off between accuracy and speed, ZCBI typically employs a two-phase charging scheme that relies on an additional threshold for zero-crossing detection. This paper proposes a simpler realization method of the two-phase charging scheme by means of charge sharing. To demonstrate feasibility of the proposed method, we designed and fabricated a second-order delta-sigma modulator in 180-nm complementary metal–oxide–semiconductor (CMOS) technology. The measurement results show that the modulator exhibits a peak signal-to-noise-and-distortion ratio (SNDR) of 46.3 dB over the bandwidth of 156 kHz with the power consumption of 684 µW. We also designed the same modulator in 65-nm CMOS technology and simulation results imply that the proposed circuit is able to achieve a much better energy efficiency in advanced technology. Full article
(This article belongs to the Section Circuit and Signal Processing)
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Open AccessFeature PaperArticle
Evaluation of Direct Torque Control with a Constant-Frequency Torque Regulator under Various Discrete Interleaving Carriers
Electronics 2019, 8(7), 820; https://doi.org/10.3390/electronics8070820 - 23 Jul 2019
Cited by 4 | Viewed by 1377
Abstract
Constant-frequency torque regulator–based direct torque control (CFTR-DTC) provides an attractive and powerful control strategy for induction and permanent-magnet motors. However, this scheme has two major issues: A sector-flux droop at low speed and poor torque dynamic performance. To improve the performance of this [...] Read more.
Constant-frequency torque regulator–based direct torque control (CFTR-DTC) provides an attractive and powerful control strategy for induction and permanent-magnet motors. However, this scheme has two major issues: A sector-flux droop at low speed and poor torque dynamic performance. To improve the performance of this control method, interleaving triangular carriers are used to replace the single carrier in the CFTR controller to increase the duty voltage cycles and reduce the flux droop. However, this method causes an increase in the motor torque ripple. Hence, in this work, different discrete steps when generating the interleaving carriers in CFTR-DTC of an induction machine are compared. The comparison involves the investigation of the torque dynamic performance and torque and stator flux ripples. The effectiveness of the proposed CFTR-DTC with various discrete interleaving-carriers is validated through simulation and experimental results. Full article
(This article belongs to the Section Power Electronics)
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Open AccessArticle
On Performance Analysis of Underlay Cognitive Radio-Aware Hybrid OMA/NOMA Networks with Imperfect CSI
Electronics 2019, 8(7), 819; https://doi.org/10.3390/electronics8070819 - 22 Jul 2019
Cited by 23 | Viewed by 2010
Abstract
This study considers the outage and throughput performance of downlink in the secondary network of cognitive radio assisted non-orthogonal multiple access (NOMA) systems. Both orthogonal multiple access (OMA) mode and NOMA mode are investigated with respect to status of decoding operation of each [...] Read more.
This study considers the outage and throughput performance of downlink in the secondary network of cognitive radio assisted non-orthogonal multiple access (NOMA) systems. Both orthogonal multiple access (OMA) mode and NOMA mode are investigated with respect to status of decoding operation of each user. Depending on the transmit signal-to-noise ratio (SNR) at the primary source and interference constraint from the primary network, the closed-form expressions of the outage probability for two users are obtained and compared in terms of performance. To obtain further insights, an asymptotic analysis of the outage probability in the high SNR regime is presented. Optimal throughput also provides insight in the computation of the power allocation factor. Furthermore, power allocation factor, target rates, and transmit SNR are evaluated to obtain reasonable outage performance. Monte Carlo simulations are conducted to confirm the analytical results. Full article
(This article belongs to the Special Issue Cooperative Communications for Future Wireless Systems)
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Open AccessArticle
Choosing the Best Locomotion Mode in Reconfigurable Rovers
Electronics 2019, 8(7), 818; https://doi.org/10.3390/electronics8070818 - 22 Jul 2019
Viewed by 1428
Abstract
The use of autonomous rovers for planetary exploration is crucial to traverse long distances and perform new discoveries on other planets. One of the most important issues is related to the interaction between the rover wheel and terrain, which would help to save [...] Read more.
The use of autonomous rovers for planetary exploration is crucial to traverse long distances and perform new discoveries on other planets. One of the most important issues is related to the interaction between the rover wheel and terrain, which would help to save energy and even avoid getting entrapped. The use of reconfigurable rovers with different locomotion modes has demonstrated improvement of traction and energy consumption. Therefore, the objective of this paper is to determine the best locomotion mode during the rover traverse, based on simple parameters, which would be obtained from propioceptive sensors. For this purpose, interaction of different terrains have been modelled and analysed with the ExoTeR, a scale prototype rover of the European ExoMars 2020 mission. This rover is able to perform, among others, the wheel walking locomotion mode, which has been demonstrated to improve traction in different situations. Currently, it is difficult to decide the instant time the rover has to switch from this locomotion mode to another. This paper also proposes a novel method to estimate the slip ratio, useful for deciding the best locomotion mode. Finally, results are obtained from an immersive simulation environment. It shows how each locomotion mode is suitable for different terrains and slopes and the proposed method is able to estimate the slip ratio. Full article
(This article belongs to the Special Issue Motion Planning and Control for Robotics)
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Open AccessArticle
Enabling Non-Linear Energy Harvesting in Power Domain Based Multiple Access in Relaying Networks: Outage and Ergodic Capacity Performance Analysis
Electronics 2019, 8(7), 817; https://doi.org/10.3390/electronics8070817 - 22 Jul 2019
Cited by 5 | Viewed by 1381
Abstract
The Power Domain-based Multiple Access (PDMA) scheme is considered as one kind of Non-Orthogonal Multiple Access (NOMA) in green communications and can support energy-limited devices by employing wireless power transfer. Such a technique is known as a lifetime-expanding solution for operations in future [...] Read more.
The Power Domain-based Multiple Access (PDMA) scheme is considered as one kind of Non-Orthogonal Multiple Access (NOMA) in green communications and can support energy-limited devices by employing wireless power transfer. Such a technique is known as a lifetime-expanding solution for operations in future access policy, especially in the deployment of power-constrained relays for a three-node dual-hop system. In particular, PDMA and energy harvesting are considered as two communication concepts, which are jointly investigated in this paper. However, the dual-hop relaying network system is a popular model assuming an ideal linear energy harvesting circuit, as in recent works, while the practical system situation motivates us to concentrate on another protocol, namely non-linear energy harvesting. As important results, a closed-form formula of outage probability and ergodic capacity is studied under a practical non-linear energy harvesting model. To explore the optimal system performance in terms of outage probability and ergodic capacity, several main parameters including the energy harvesting coefficients, position allocation of each node, power allocation factors, and transmit signal-to-noise ratio (SNR) are jointly considered. To provide insights into the performance, the approximate expressions for the ergodic capacity are given. By matching analytical and Monte Carlo simulations, the correctness of this framework can be examined. With the observation of the simulation results, the figures also show that the performance of energy harvesting-aware PDMA systems under the proposed model can satisfy the requirements in real PDMA applications. Full article
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Open AccessArticle
Optimal Scheduling Strategy of Distribution Network Based on Electric Vehicle Forecasting
Electronics 2019, 8(7), 816; https://doi.org/10.3390/electronics8070816 - 22 Jul 2019
Cited by 2 | Viewed by 1098
Abstract
Based on the Monte Carlo method, this paper simulates, predicts the load, and considers the travel chain of electric vehicles and different charging methods to establish a predictive model. Based on the results of electric vehicle simulation prediction, an optimal scheduling model of [...] Read more.
Based on the Monte Carlo method, this paper simulates, predicts the load, and considers the travel chain of electric vehicles and different charging methods to establish a predictive model. Based on the results of electric vehicle simulation prediction, an optimal scheduling model of the distribution network considering the demand response side load is established. The firefly optimization algorithm is used to solve the optimal scheduling problem. The results show that the prediction model proposed in this paper has a certain reference value for the prediction of an electric vehicle load. The electric vehicle is placed in the optimal scheduling resource of the distribution network, which increases the dimension of the scheduling resources of the network and improves the economics of the distribution network operation. Full article
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Open AccessArticle
High-Throughput and Low-Latency Digital Baseband Architecture for Energy-Efficient Wireless VR Systems
Electronics 2019, 8(7), 815; https://doi.org/10.3390/electronics8070815 - 22 Jul 2019
Cited by 2 | Viewed by 1393
Abstract
This paper presents a novel baseband architecture that supports high-speed wireless VR solutions using 60 GHz RF circuits. Based on the experimental observations by our previous 60 GHz transceiver circuits, the efficient baseband architecture is proposed to enhance the quality of transmission. To [...] Read more.
This paper presents a novel baseband architecture that supports high-speed wireless VR solutions using 60 GHz RF circuits. Based on the experimental observations by our previous 60 GHz transceiver circuits, the efficient baseband architecture is proposed to enhance the quality of transmission. To achieve a zero-latency transmission, we define an (106,920, 95,040) interleaved-BCH error-correction code (ECC), which removes iterative processing steps in the previous LDPC ECC standardized for the near-field wireless communication. Introducing the block-level interleaving, the proposed baseband processing successfully scatters the existing burst errors to the small-sized component codes, and recovers up to 1080 consecutive bit errors in a data frame of 106,920 bits. To support the high-speed wireless VR system, we also design the massive-parallel BCH encoder and decoder, which is tightly connected to the block-level interleaver and de-interleaver. Including the high-speed analog interfaces for the external devices, the proposed baseband architecture is designed in 65 nm CMOS, supporting a data rate of up to 12.8 Gbps. Experimental results show that the proposed wireless VR solution can transfer up to 4 K high-resolution video streams without using time-consuming compression and decompression, successfully achieving a transfer latency of 1 ms. Full article
(This article belongs to the Special Issue VLSI Architecture Design for Digital Signal Processing)
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Open AccessArticle
A High-Accuracy Ultra-Low-Power Offset-Cancelation On-Off Bandgap Reference for Implantable Medical Electronics
Electronics 2019, 8(7), 814; https://doi.org/10.3390/electronics8070814 - 21 Jul 2019
Cited by 1 | Viewed by 1243
Abstract
An ultra-low-power and high-accuracy on-off bandgap reference (BGR) is demonstrated in this paper for implantable medical electronics. The proposed BGR shows an average current consumption of 78 nA under 2.8 V supply and an output voltage of 1.17 V with an untrimmed accuracy [...] Read more.
An ultra-low-power and high-accuracy on-off bandgap reference (BGR) is demonstrated in this paper for implantable medical electronics. The proposed BGR shows an average current consumption of 78 nA under 2.8 V supply and an output voltage of 1.17 V with an untrimmed accuracy of 0.69%. The on-off bandgap combined with sample-and-hold switched-RC filter is developed to reduce power consumption and noise. The on-off mechanism allows a relatively higher current in the sample phase to alleviate the process variation of bipolar transistors. To compensate the error caused by operational amplifier offset, the correlated double sampling strategy is adopted in the BGR. The proposed BGR is implemented in 0.35 μm standard CMOS process and occupies a total area of 0.063 mm2. Measurement results show that the circuit works properly in the supply voltage range of 1.8–3.2 V and achieves a line regulation of 0.59 mV/V. When the temperature varies from −20 to 80 °C, an average temperature coefficient of 19.6 ppm/°C is achieved. Full article
(This article belongs to the Section Microelectronics and Optoelectronics)
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Open AccessArticle
Design of an Oscillation-Based BIST System for Active Analog Integrated Filters in 0.18 µm CMOS
Electronics 2019, 8(7), 813; https://doi.org/10.3390/electronics8070813 - 20 Jul 2019
Cited by 2 | Viewed by 1044
Abstract
In this paper, an oscillation-based built-in self-test system for active an analog integrated circuit is presented. This built-in self-test system was used to detect catastrophic and parametric faults, introduced during chip manufacturing. As circuits under test (CUT), second-order Sallen-Key, Akerberg-Mossberg and Tow-Thomas biquad [...] Read more.
In this paper, an oscillation-based built-in self-test system for active an analog integrated circuit is presented. This built-in self-test system was used to detect catastrophic and parametric faults, introduced during chip manufacturing. As circuits under test (CUT), second-order Sallen-Key, Akerberg-Mossberg and Tow-Thomas biquad filters were designed. The proposed test hardware detects parametric and catastrophic faults on changeable limits. The influence of both oscillation and test hardware on fault detection limits were investigated and analyzed. The proposed oscillation based self-test system was designed and simulated in 0.18 µm complementary metal-oxide semiconductor (CMOS) technology. Due to the easiness of implementation and configuration for testing of different active analog filters, such self-test systems can be effectively used in modern integrated circuits, made of a large number of devices and circuits, such as the multi-standard transceivers used in the core hardware of software-defined radios. Using the proposed test strategy, the fault tolerance limits for catastrophic faults varied from 96% to 100% for all injected faults in different structures of low pass filters (LPF). The detection range of parametric faults of passive components’ nominal value, depending on the used structure of the filter, did not exceed –0.74% – 0.72% in case of Sallen-Key, –3.31% – 1.00% in case of Akerberg-Mossberg and –2.39% – 1.44% in case of Tow-Thomas LPF. Full article
(This article belongs to the Section Microelectronics and Optoelectronics)
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Open AccessArticle
Unobtrusive Sleep Monitoring Using Movement Activity by Video Analysis
Electronics 2019, 8(7), 812; https://doi.org/10.3390/electronics8070812 - 20 Jul 2019
Cited by 4 | Viewed by 1201
Abstract
Sleep healthcare at home is a new research topic that needs to develop new sensors, hardware and algorithms with the consideration of convenience, portability and accuracy. Monitoring sleep behaviors by visual sensors represents one new unobtrusive approach to facilitating sleep monitoring and benefits [...] Read more.
Sleep healthcare at home is a new research topic that needs to develop new sensors, hardware and algorithms with the consideration of convenience, portability and accuracy. Monitoring sleep behaviors by visual sensors represents one new unobtrusive approach to facilitating sleep monitoring and benefits sleep quality. The challenge of video surveillance for sleep behavior analysis is that we have to tackle bad image illumination issue and large pose variations during sleeping. This paper proposes a robust method for sleep pose analysis with human joints model. The method first tackles the illumination variation issue of infrared videos to improve the image quality and help better feature extraction. Image matching by keypoint features is proposed to detect and track the positions of human joints and build a human model robust to occlusion. Sleep poses are then inferred from joint positions by probabilistic reasoning in order to tolerate occluded joints. Experiments are conducted on the video polysomnography data recorded in sleep laboratory. Sleep pose experiments are given to examine the accuracy of joint detection and tacking, and the accuracy of sleep poses. High accuracy of the experiments demonstrates the validity of the proposed method. Full article
(This article belongs to the Special Issue Sensing and Signal Processing in Smart Healthcare)
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Open AccessArticle
A Smart Binaural Hearing Aid Architecture Based on a Mobile Computing Platform
Electronics 2019, 8(7), 811; https://doi.org/10.3390/electronics8070811 - 20 Jul 2019
Cited by 2 | Viewed by 1321
Abstract
This paper presents a new structure for hearing aids. Normally, the power consumption and user experience are contradictory. The proposed hearing aid structure mainly consists of three parts: the earpieces, the mobile computing platform, and the real-time speech-enhancement application. It can run complex [...] Read more.
This paper presents a new structure for hearing aids. Normally, the power consumption and user experience are contradictory. The proposed hearing aid structure mainly consists of three parts: the earpieces, the mobile computing platform, and the real-time speech-enhancement application. It can run complex algorithms without carrying out heavy calculations on the processors in the hearing aid. Thus, the binaural algorithm is utilized without being limited by complexity and power consumption to improve the user experience. Moreover, the speech-enhancement algorithm can be updated much more easily than in traditional built-in digital signal process hearing aids. A good level of user experience is achieved by combining the hearing aid and mobile computing platform with a 400-MHz transceiver; furthermore, the 400-MHz transceiver can reduce path loss around the body. The concept verification process showed that the overall usage of the central processing unit in the smartphone is around 16%, the signal-to-noise ratios show at least a 30% improvement in some environments, and the whole system delay is 8.8 ms. The presented objective and subjective results show significant improvements regarding user experience and usability brought about by the proposed structure. Full article
(This article belongs to the Section Bioelectronics)
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Open AccessArticle
Customized Vibration Generator for State of Health Monitoring of Prosthetic Implants and Pseudo-Bionic Machine–Human Feedbacks
Electronics 2019, 8(7), 810; https://doi.org/10.3390/electronics8070810 - 19 Jul 2019
Viewed by 1189
Abstract
Modern industrial, household and other equipment include sophisticated power mechanisms and complicated control solutions that require tighter human–machine–human interactions to form the structures known as cyber–physical–human systems. Their significant parts are human–machine command links and machine–human feedbacks. Such systems are found in medicine, [...] Read more.
Modern industrial, household and other equipment include sophisticated power mechanisms and complicated control solutions that require tighter human–machine–human interactions to form the structures known as cyber–physical–human systems. Their significant parts are human–machine command links and machine–human feedbacks. Such systems are found in medicine, e.g., in orthopedics, where they are important for the operation and functional abilities of orthopedic devices—wheelchair, prosthesis, rehabilitation units, etc. The mentioned feedbacks may be implemented based on the haptic perceptions that requires vibration actuators. In orthopedics, such actuators can be used also for diagnostic purposes. This research brings forward the idea of the use of 3D printing in conjunction with high quality permanent magnets. This allows for the achievement of better efficiency, smaller size, and the developing of actuators individually for particular circumstances. The obtained simulation, experimental data, and data about 3D manufacturing generally confirm the above hypothesis. In particular, the stiffness coefficient of the actuator’s membrane and attached mass, which can be changed easily during 3D printing, affects the frequency of maximal power output. Secondly, the 3D manufacturing process is quick, tunable and rather cheap. Finally, an elaboration of the design of the actuator that allows for the real-time modification of stiffness and mass in a program way is planned for future works. Full article
(This article belongs to the Special Issue Recent Advances in Biometrics and its Applications)
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Open AccessFeature PaperArticle
Ancillary Service with Grid Connected PV: A Real-Time Hardware-in-the-Loop Approach for Evaluation of Performances
Electronics 2019, 8(7), 809; https://doi.org/10.3390/electronics8070809 - 19 Jul 2019
Cited by 3 | Viewed by 1186
Abstract
The integration of photovoltaic (PV) systems with the grid is undoubtedly an issue of great interest both in terms of energy production, but also as a support to the grid as an ancillary service, but to evaluate the performance of the use of [...] Read more.
The integration of photovoltaic (PV) systems with the grid is undoubtedly an issue of great interest both in terms of energy production, but also as a support to the grid as an ancillary service, but to evaluate the performance of the use of PV in an unconventional way, it is necessary to have reference models to be applied to evaluate the characteristics and integration requirements. In this work, an ancillary service provided by a grid-connected PV is shown and a hardware in the loop simulation environment is created to simulate performances and integration issues. Full article
(This article belongs to the Special Issue Grid Connected Photovoltaic Systems)
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Open AccessArticle
A Context-Aware Route Finding Algorithm for Self-Driving Tourists Using Ontology
Electronics 2019, 8(7), 808; https://doi.org/10.3390/electronics8070808 - 19 Jul 2019
Cited by 1 | Viewed by 1057
Abstract
This study proposed a context-aware ontology-based route finding algorithm for self-driving tourists. In this algorithm, two ontologies—namely drivers’ experiences and required tourist services—were used according to tourist requirements. Trips were classified into business and touristic. The algorithm was then compared with Google Maps [...] Read more.
This study proposed a context-aware ontology-based route finding algorithm for self-driving tourists. In this algorithm, two ontologies—namely drivers’ experiences and required tourist services—were used according to tourist requirements. Trips were classified into business and touristic. The algorithm was then compared with Google Maps in terms of travel time and travel length for evaluation. The results showed that the proposed algorithm performed similarly to Google Maps in some cases of business trips and better in other cases, with a maximum 10-min travel time difference. In touristic trips, the capabilities of the proposed algorithm were far better than those of Google Maps. Full article
(This article belongs to the Section Computer Science & Engineering)
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Open AccessArticle
FT-GAN: Face Transformation with Key Points Alignment for Pose-Invariant Face Recognition
Electronics 2019, 8(7), 807; https://doi.org/10.3390/electronics8070807 - 19 Jul 2019
Cited by 3 | Viewed by 1882
Abstract
Face recognition has been comprehensively studied. However, face recognition in the wild still suffers from unconstrained face directions. Frontal face synthesis is a popular solution, but some facial features are missed after synthesis. This paper presents a novel method for pose-invariant face recognition. [...] Read more.
Face recognition has been comprehensively studied. However, face recognition in the wild still suffers from unconstrained face directions. Frontal face synthesis is a popular solution, but some facial features are missed after synthesis. This paper presents a novel method for pose-invariant face recognition. It is based on face transformation with key points alignment based on generative adversarial networks (FT-GAN). In this method, we introduce CycleGAN for pixel transformation to achieve coarse face transformation results, and these results are refined by key point alignment. In this way, frontal face synthesis is modeled as a two-task process. The results of comprehensive experiments show the effectiveness of FT-GAN. Full article
(This article belongs to the Special Issue Multidimensional Digital Signal Processing)
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Open AccessArticle
Continuous and Stable Cross-Eye Jamming via a Circular Retrodirective Array
Electronics 2019, 8(7), 806; https://doi.org/10.3390/electronics8070806 - 19 Jul 2019
Viewed by 1011
Abstract
Cross-eye jamming is an angular deception jamming technique against monopulse radar. Multiple-element retrodirective cross-eye jamming (MRCJ) as an improved method, uses a retrodirective antenna array with multiple antenna elements in a cross-eye jammer and can obtain better jamming performance. However, the practical MRCJ [...] Read more.
Cross-eye jamming is an angular deception jamming technique against monopulse radar. Multiple-element retrodirective cross-eye jamming (MRCJ) as an improved method, uses a retrodirective antenna array with multiple antenna elements in a cross-eye jammer and can obtain better jamming performance. However, the practical MRCJ system employing a linear antenna array becomes ineffective when the threat radar appears in the antenna array’s end-fire direction. To meet multiple threats from different directions and provide continuous jamming, MRCJ employing a circular antenna array (C-MRCJ) is proposed after defining the modulation direction of system parameters. Optimal configuration of C-MRCJ providing stable jamming performance is discussed. The number of the jammer loops is analyzed under considerable jamming performance and moderate hardware cost. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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Open AccessArticle
Improvement in SNR by Adaptive Range Gates for RCS Measurements in the THz Region
Electronics 2019, 8(7), 805; https://doi.org/10.3390/electronics8070805 - 18 Jul 2019
Cited by 1 | Viewed by 1056
Abstract
One of the major concerns in radar cross-section (RCS) measurements is the isolation of the target echo from unwanted spurious signals. Generally, the method of software range gate is applied to extract useful data. However, this method may not work to expectations, especially [...] Read more.
One of the major concerns in radar cross-section (RCS) measurements is the isolation of the target echo from unwanted spurious signals. Generally, the method of software range gate is applied to extract useful data. However, this method may not work to expectations, especially for targets with a large length-width ratio. This is because the effective target zone is dependent on the aspect angle. The implementation of conventional fixed range gates will introduce an uneven clutter signal that leads to a decline in signal-to-noise ratio. The influence of this uneven clutter signal becomes increasingly severe in the terahertz band, where the wavelength is short and the illumination power is weak. In this work, the concept of adaptive range gates was adopted to extract a target echo of higher accuracy. The dimension of the range gate was determined by the angle-dependent radial projection of the target. In order to evaluate the performance of the proposed method, both experimental measurements and numerical simulations were conducted. Noticeable improvements in the signal-to-noise ratio at certain angles were observed. Full article
(This article belongs to the Special Issue Terahertz Technology and Its Applications)
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Open AccessArticle
Prototyping of an All-pMOS-Based Cross-Coupled Voltage Multiplier in Single-Well CMOS Technology for Energy Harvesting Utilizing a Gastric Acid Battery
Electronics 2019, 8(7), 804; https://doi.org/10.3390/electronics8070804 - 18 Jul 2019
Cited by 1 | Viewed by 1137
Abstract
A gastric acid battery and its charge storage in a capacitor are a simple and safe method to provide a power source to an ingestible device. For that method, the electromotive force of the battery should be boosted for storing a large amount [...] Read more.
A gastric acid battery and its charge storage in a capacitor are a simple and safe method to provide a power source to an ingestible device. For that method, the electromotive force of the battery should be boosted for storing a large amount of energy. In this study, we have proposed an all-p-channel metal-oxide semiconductor (pMOS)-based cross-coupled voltage multiplier (CCVM) utilizing single-well CMOS technology to achieve a voltage boosting higher than from a conventional complementary MOS (CMOS) CCVM. We prototyped a custom integrated circuit (IC) implemented with the above CCVMs and a ring oscillator as a clock source. The characterization experiment demonstrated that our proposed pMOS-based CCVM can boost the input voltage higher because it avoids the body effect problem resulting from an n-channel MOS transistor. This circuit was also demonstrated to significantly reduce the circuit area on the IC, which is advantageous as it reduces the chip size or provides an area for other functional circuits. This simple circuit structure based on mature and low-cost technologies matches well with disposal applications such as an ingestible device. We believe that this pMOS-based CCVM has the potential to become a useful energy harvesting circuit for ingestible devices. Full article
(This article belongs to the Special Issue Energy Efficient Circuit Design Techniques for Low Power Systems)
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Open AccessArticle
Efficient Implementation of 2D and 3D Sparse Deconvolutional Neural Networks with a Uniform Architecture on FPGAs
Electronics 2019, 8(7), 803; https://doi.org/10.3390/electronics8070803 - 18 Jul 2019
Cited by 3 | Viewed by 1110
Abstract
Three-dimensional (3D) deconvolution is widely used in many computer vision applications. However, most previous works have only focused on accelerating two-dimensional (2D) deconvolutional neural networks (DCNNs) on Field-Programmable Gate Arrays (FPGAs), while the acceleration of 3D DCNNs has not been well studied in [...] Read more.
Three-dimensional (3D) deconvolution is widely used in many computer vision applications. However, most previous works have only focused on accelerating two-dimensional (2D) deconvolutional neural networks (DCNNs) on Field-Programmable Gate Arrays (FPGAs), while the acceleration of 3D DCNNs has not been well studied in depth as they have higher computational complexity and sparsity than 2D DCNNs. In this paper, we focus on the acceleration of both 2D and 3D sparse DCNNs on FPGAs by proposing efficient schemes for mapping 2D and 3D sparse DCNNs on a uniform architecture. Firstly, a pruning method is used to prune unimportant network connections and increase the sparsity of weights. After being pruned, the number of parameters of DCNNs is reduced significantly without accuracy loss. Secondly, the remaining non-zero weights are encoded in coordinate (COO) format, reducing the memory demands of parameters. Finally, to demonstrate the effectiveness of our work, we implement our accelerator design on the Xilinx VC709 evaluation platform for four real-life 2D and 3D DCNNs. After the first two steps, the storage required of DCNNs is reduced up to 3.9×. Results show that the performance of our method on the accelerator outperforms that of the our prior work by 2.5× to 3.6× in latency. Full article
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Open AccessArticle
A n-out-of-n Sharing Digital Image Scheme by Using Color Palette
Electronics 2019, 8(7), 802; https://doi.org/10.3390/electronics8070802 - 17 Jul 2019
Viewed by 1043
Abstract
A secret image sharing (SIS) scheme inserts a secret message into shadow images in a way that if shadow images are combined in a specific way, the secret image can be recovered. A 2-out-of-2 sharing digital image scheme (SDIS) adopts a color palette [...] Read more.
A secret image sharing (SIS) scheme inserts a secret message into shadow images in a way that if shadow images are combined in a specific way, the secret image can be recovered. A 2-out-of-2 sharing digital image scheme (SDIS) adopts a color palette to share a digital color secret image into two shadow images, and the secret image can be recovered from two shadow images, while any one shadow image has no information about the secret image. This 2-out-of-2 SDIS may keep the shadow size small because by using a color palette, and thus has advantage of reducing storage. However, the previous works on SDIS are just 2-out-of-2 scheme and have limited functions. In this paper, we take the lead to study a general n-out-of-n SDIS which can be applied on more than two shadow. The proposed SDIS is implemented on the basis of 2-out-of-2 SDIS. Our main contribution has the higher contrast of binary meaningful shadow and the larger region in color shadows revealing cover image when compared with previous 2-out-of-2 SDISs. Meanwhile, our SDIS is resistant to colluder attack. Full article
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Open AccessArticle
An Intelligent Air Quality Sensing System for Open-Skin Wound Monitoring
Electronics 2019, 8(7), 801; https://doi.org/10.3390/electronics8070801 - 17 Jul 2019
Cited by 3 | Viewed by 1297
Abstract
There are many factors that may have a significant effect on the skin wound healing process. The environment is one of them. Although different previous research woks have highlighted the role of environmental elements such as humidity, temperature, dust, etc., in the process [...] Read more.
There are many factors that may have a significant effect on the skin wound healing process. The environment is one of them. Although different previous research woks have highlighted the role of environmental elements such as humidity, temperature, dust, etc., in the process of skin wound healing, there is no predefined method available to identify the favourable or adverse environment conditions that seriously affect (positively or negatively) the skin wound healing process. In the current research work, an IoT-based approach is used to design an AQSS (Air Quality Sensing System) using sensors for the acquisition of real-time environment data, and the SVM (Support Vector Machine) classifier is applied to classify environments into one of the two categories, i.e., “favourable”, and “unfavourable”. The proposed system is also supported with an Android application to provide an easy-to-use interface. The proposed system provides an easy and simple means for patients to evaluate the environmental parameters and monitor their effects in the process of open skin wound healing. Full article
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Open AccessArticle
Effectiveness Assessment of a Nanocrystalline Sleeve Ferrite Core Compared with Ceramic Cores for Reducing Conducted EMI
Electronics 2019, 8(7), 800; https://doi.org/10.3390/electronics8070800 - 17 Jul 2019
Cited by 6 | Viewed by 1725
Abstract
The interconnection of different electronic devices or systems through cables is becoming more difficult due to the hard restrictions related to electromagnetic compatibility (EMC) in order to comply with requirements. Therefore, the use of EMC components is a good solution to manage the [...] Read more.
The interconnection of different electronic devices or systems through cables is becoming more difficult due to the hard restrictions related to electromagnetic compatibility (EMC) in order to comply with requirements. Therefore, the use of EMC components is a good solution to manage the problems associated with the filtering of electromagnetic interference (EMI) in cables and to pass the compliance test. In this sense, sleeve ferrite cores become a very interesting solution since they can be set around a wire and, hence, they provide an effective solution against EMI without having to redesign the electronic circuit. This contribution is focused on the characterization of the performance of a sleeve ferrite core based on a novel nanocrystalline (NC) novel material for EMI suppression and comparing it to the most conventional ceramic ferrite cores such as MnZn and NiZn. The research highlights the suitability of an NC novel component in terms of its magnetic properties to reduce EMI within the conducted emissions range. This range is generally defined by the International Special Committee on Radio Interference (CISPR) test standards frequency band that covers from 150 kHz up to 30 MHz (108 MHz in the case of CISPR 25). First, this study presents a description of the main parameters that define the behavior of NC and ceramic cores and, secondly, by analyzing the data obtained from experimental procedures, it is possible to directly determine the insertion loss parameter. Hence, this characterization procedure is used to obtain the performance of NC material compared to the conventional sleeve ferrite core compositions employed to filter the interferences in this problematic frequency range. As can be deduced from the results obtained, an NC sleeve ferrite core provides the best performance in terms of EMI filtering within a significant frequency range between 100 kHz and 100 MHz. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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Open AccessArticle
Model-Based Optimization of an LLC-Resonant DC-DC Converter
Electronics 2019, 8(7), 799; https://doi.org/10.3390/electronics8070799 - 17 Jul 2019
Cited by 2 | Viewed by 992
Abstract
The study presented in the paper is to guarantee the performance of the LLC DC-DC converter using model-based optimization. The primary scope of the study is to maintain the output parameters regardless of the variation of the values of the circuit elements. In [...] Read more.
The study presented in the paper is to guarantee the performance of the LLC DC-DC converter using model-based optimization. The primary scope of the study is to maintain the output parameters regardless of the variation of the values of the circuit elements. In engineering practice, it is known that any schematic element cannot be reproduced with an absolute accuracy of features. In addition, its main parameters change during operation due to changes in operating temperature, aging, operating modes and so on. Optimization procedures are a tool for finding the most appropriate values for circuit elements, with selected constraints, target functions and operating modes. In electronic converters, these are most often: minimal loss, maximum efficiency, the critical-aperiodic transition process, realization of certain dynamics, appropriate modes of operation and so on. The results obtained show that using the proposed approach produces more robustness to disturbances and tolerances, with improved dynamics and faster transient processes. On the other hand, the value of the circuit elements is smaller, and reliable operation of the protection and automatic regulation systems is achieved. Full article
(This article belongs to the Section Power Electronics)
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Open AccessArticle
Single-Switch LED Post-Regulator Based on a Modified Class-E Resonant Converter with Voltage Clamp
Electronics 2019, 8(7), 798; https://doi.org/10.3390/electronics8070798 - 16 Jul 2019
Cited by 2 | Viewed by 1171
Abstract
The strict restrictions imposed both by mandatory regulations and by the recommendations contained in current standards have led to the fact that most commercially available LED ballasts nowadays use two-stage topologies. The first stage is intended to comply with the harmonics standards and [...] Read more.
The strict restrictions imposed both by mandatory regulations and by the recommendations contained in current standards have led to the fact that most commercially available LED ballasts nowadays use two-stage topologies. The first stage is intended to comply with the harmonics standards and the second stage is used to control the LED current and reduce the low frequency ripple. In this work, a new DC–DC resonant converter topology is presented. This topology is derived from a modified Class-E resonant inverter by adding a clamping diode. This diode achieves a double goal: it limits the maximum switch voltage and works as a power recirculating path. This way, the proposed topology behaves as a loss-less impedance placed in series with the LED thus allowing to control the output power. This converter maintains the extremely small switching losses inherent to the Class-E inverter while reducing the voltage stress across the switch. This work presents a simplified design methodology based on the fundamental approach. This methodology was used to design and build a DC–DC post-regulator for a 40 W LED lamp. The results obtained with the laboratory prototype show that this circuit can be used to stabilize and dim the LED current while maintaining very small losses. The measured efficiency was 95.7% at nominal power and above 90% when dimmed down to 25%. Full article
(This article belongs to the Special Issue Latest Developments in LED Drivers)
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Open AccessArticle
Near-Field Immunity Test Method for Fast Radiated Immunity Test Debugging of Automotive Electronics
Electronics 2019, 8(7), 797; https://doi.org/10.3390/electronics8070797 - 16 Jul 2019
Cited by 1 | Viewed by 1427
Abstract
This study presents a near-field immunity test (NFIT) method for the fast debugging of radiated susceptibility of industrial devices. The proposed approach is based on the development of an NFIT setup which comprises of developed near-field electric and magnetic field probes and device [...] Read more.
This study presents a near-field immunity test (NFIT) method for the fast debugging of radiated susceptibility of industrial devices. The proposed approach is based on the development of an NFIT setup which comprises of developed near-field electric and magnetic field probes and device under test (DUT). The developed small-size and handy near-field testing probes inject the high electric (up to 1000 V/m) and magnetic (up to 2.4 A/m) fields on the DUT in the radar pulse ranges (1.2 to 1.4 GHz and 2.7 to 3.1 GHz) with the lower fed input power (up to 15 W) from the power amplifier in the developed NFIT setup. The proof of concept is validated with the successful near-field immunity debugging of an electric power steering (EPS) device used in the automotive industry with the developed NFIT setup. The radiated susceptibility debugging test results of developed NFIT method and conventional method of ISO 11452-2 test setup turned out to be close to each other for the tested DUT in immunity performance. The proposed procedure has advantages of industry usefulness with fast, handy, and cost-effective radiated immunity debugging of the DUT without the requirement of large antenna, high-power amplifiers, optical DUT connecting harness, and an anechoic chamber as needed in ISO 11452-2 standard setup for the debugging analysis. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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Open AccessFeature PaperArticle
Maximum Transmit Power for UE in an LTE Small Cell Uplink
Electronics 2019, 8(7), 796; https://doi.org/10.3390/electronics8070796 - 16 Jul 2019
Cited by 5 | Viewed by 1285
Abstract
To furnish the network with small cells, it is vital to consider parameters like cell size, interference in the network, and deployment strategies to maximize the network’s performance gains expected from small cells. With a small cell network, it is critical to analyze [...] Read more.
To furnish the network with small cells, it is vital to consider parameters like cell size, interference in the network, and deployment strategies to maximize the network’s performance gains expected from small cells. With a small cell network, it is critical to analyze the impact of the uplink power control parameters on the network’s performance. In particular, the maximum transmit power (Pmax) for user equipment (UE) needs to be revisited for small cells, since it is a major contributor towards interference. In this work, the network performance was evaluated for different Pmax values for the small cell uplink. Various deployment scenarios for furnishing the existing macro layer in LTE networks with small cells were considered. The Pmax limit for a small cell uplink was evaluated for both homogenous small cell and heterogeneous networks (HetNet). The numerical results showed that it would be appropriate to adopt Pmax = 18 dBm in uniformly distributed small cells rather than Pmax = 23 dBm, as in macro environments. The choice of Pmax = 18 dBm was further validated for three HetNet deployment scenarios. A decrease of 0.52 dBm and an increase of 0.03 dBm and 3.29 dBm in the proposed Pmax = 18 dBm were observed for the three HetNet deployments, respectively. Furthermore, we propose that the fractional power control mode can be employed instead of the full compensation mode in small cell uplinks. Full article
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Open AccessFeature PaperArticle
A Multi-Inductor H Bridge Fault Current Limiter
Electronics 2019, 8(7), 795; https://doi.org/10.3390/electronics8070795 - 16 Jul 2019
Cited by 4 | Viewed by 1446
Abstract
Current power systems will suffer from increasing pressure as a result of an upsurge in demand and will experience an ever-growing penetration of distributed power generation, which are factors that will contribute to a higher of incidence fault current levels. Fault current limiters [...] Read more.
Current power systems will suffer from increasing pressure as a result of an upsurge in demand and will experience an ever-growing penetration of distributed power generation, which are factors that will contribute to a higher of incidence fault current levels. Fault current limiters (FCLs) are key power electronic devices. They are able to limit the prospective fault current without completely disconnecting in cases in which a fault occurs, for instance, in a power transmission grid. This paper proposes a new type of FCL capable of fault current limiting in two steps. In this way, the FCLs’ power electronic switches experience significantly less stress and their overall performance will significantly increase. The proposed device is essentially a controllable H bridge type fault current limiter (HBFCL) that is comprised of two variable inductances, which operate to reduce current of main switch in the first stage of current limiting. In the next step, the main switch can limit the fault current while it becomes open. Simulation studies are carried out using MATLAB and its prototype setup is built and tested. The comparison of experimental and simulation results indicates that the proposed HBFCL is a promising solution to address protection issues. Full article
(This article belongs to the Special Issue Industrial Applications of Power Electronics) Printed Edition available
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Open AccessArticle
Expressing Personalities of Conversational Agents through Visual and Verbal Feedback
Electronics 2019, 8(7), 794; https://doi.org/10.3390/electronics8070794 - 16 Jul 2019
Cited by 2 | Viewed by 1082
Abstract
As the uses of conversational agents increase, the affective and social abilities of agents become important with their functional abilities. Agents that lack affective abilities could frustrate users during interaction. This study applied personality to implement the natural feedback of conversational agents referring [...] Read more.
As the uses of conversational agents increase, the affective and social abilities of agents become important with their functional abilities. Agents that lack affective abilities could frustrate users during interaction. This study applied personality to implement the natural feedback of conversational agents referring to the concept of affective computing. Two types of feedback were used to express conversational agents’ personality: (1) visual feedback and (2) verbal cues. For visual feedback, participants (N = 45) watched visual feedback with different colors and motions. For verbal cues, participants (N = 60) heard different conditions of agents’ voices with different scripts. The results indicated that the motions of visual feedback were more significant than colors. Fast motions could express distinct and positive personalities. Different verbal cues were perceived as different personalities. The perceptions of personalities differed according to the vocal gender. This study provided design implications for personality expressions applicable to diverse interfaces. Full article
(This article belongs to the Special Issue Electronics and Dynamic Open Innovation)
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Open AccessArticle
Embedded Flight Control Based on Adaptive Sliding Mode Strategy for a Quadrotor Micro Air Vehicle
Electronics 2019, 8(7), 793; https://doi.org/10.3390/electronics8070793 - 16 Jul 2019
Cited by 3 | Viewed by 1002
Abstract
The design of an embedded flight controller for a quadrotor micro air vehicle, which is subject to uncertainties and perturbations, is addressed. In order to obtain robustness against bounded uncertainties and disturbances, an adaptive sliding mode controller is proposed. The control adaptive gains [...] Read more.
The design of an embedded flight controller for a quadrotor micro air vehicle, which is subject to uncertainties and perturbations, is addressed. In order to obtain robustness against bounded uncertainties and disturbances, an adaptive sliding mode controller is proposed. The control adaptive gains allow using only necessary control to satisfy the task, reducing the chattering effect and at the same time reject external perturbations. Furthermore, a stability analysis of the closed-loop system is given. Finally, simulations and experimental results carried out on a commercial micro air vehicle demonstrate the feasibility and advantages of the proposed flight controller. Full article
(This article belongs to the Special Issue Motion Planning and Control for Robotics)
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Open AccessArticle
A Study of the Sulfidation Behavior on Palladium-Coated Copper Wire with a Flash-Gold Layer (PCA) after Wire Bonding
Electronics 2019, 8(7), 792; https://doi.org/10.3390/electronics8070792 - 15 Jul 2019
Viewed by 1009
Abstract
Palladium-coated copper wire with a flash-gold layer (PCA) is an oxidation-resistant fine wire that simultaneously has the properties of palladium-coated copper wire (PCC) and gold-coated copper wire. This research used an extreme sulfidation test to compare corrosion resistance between the PCC and PCA [...] Read more.
Palladium-coated copper wire with a flash-gold layer (PCA) is an oxidation-resistant fine wire that simultaneously has the properties of palladium-coated copper wire (PCC) and gold-coated copper wire. This research used an extreme sulfidation test to compare corrosion resistance between the PCC and PCA wires. In addition to closely examining the morphology of the wires, the internal matrix after the sulfidation test is also discussed. In doing so, the PCA wire was bonded onto the aluminum pads and the sulfidation test was conducted. Then, we observed its morphology and elemental distribution and found that the flash-gold layer of the PCA wire effectively enhanced resistance to sulfidation corrosion. Because the copper ball had an alloying effect on the ball bonding, it produced different shapes of sulfide after the sulfidation test. The degree of corrosion on the wedge bond was different because of the presence or absence of the coated layer. In contrast, the flash-gold layer of the PCA wire enhanced the bonding force and retained low resistance characteristics after the sulfidation test. Full article
(This article belongs to the Section Microelectronics and Optoelectronics)
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