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Electronics, Volume 8, Issue 5 (May 2019)

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Open AccessFeature PaperArticle
Radiation Assessment of a 15.6ps Single-Shot Time-to-Digital Converter in Terms of TID
Electronics 2019, 8(5), 558; https://doi.org/10.3390/electronics8050558 (registering DOI)
Received: 25 April 2019 / Revised: 9 May 2019 / Accepted: 14 May 2019 / Published: 18 May 2019
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Abstract
This article presents a radiation tolerant single-shot time-to-digital converter (TDC) with a resolution of 15.6 ps, fabricated in a 65 nm complementary metal oxide semiconductor (CMOS) technology. The TDC is based on a multipath pseudo differential ring oscillator with reduced phase delay, without [...] Read more.
This article presents a radiation tolerant single-shot time-to-digital converter (TDC) with a resolution of 15.6 ps, fabricated in a 65 nm complementary metal oxide semiconductor (CMOS) technology. The TDC is based on a multipath pseudo differential ring oscillator with reduced phase delay, without the need for calibration or interpolation. The ring oscillator is placed inside a Phase Locked Loop (PLL) to compensate for Process, Voltage and Temperature (PVT) variations- and variations due to ionizing radiation. Measurements to evaluate the performance of the TDC in terms of the total ionizing dose (TID) were done. Two different samples were irradiated up to a dose of 2.2 MGy SiO 2 while still maintaining a resolution of 15.6 ps. The TDC has a differential non-linearity (DNL) and integral non-linearity (INL) of 0.22 LSB rms and 0.34 LSB rms respectively. Full article
(This article belongs to the Special Issue Radiation Tolerant Electronics)
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Open AccessArticle
Gridless Sparse Direction Finding Method for Correlated Signals with Gain-Phase Errors
Electronics 2019, 8(5), 557; https://doi.org/10.3390/electronics8050557 (registering DOI)
Received: 26 April 2019 / Revised: 9 May 2019 / Accepted: 15 May 2019 / Published: 17 May 2019
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Abstract
In practical array systems, the gain-phase errors among antennas degrade the performance of direction finding significantly. In this paper, a novel sparse system model for direction of arrival (DOA) estimation in the scenario with gain-phase errors is proposed by exploiting the signal sparsity [...] Read more.
In practical array systems, the gain-phase errors among antennas degrade the performance of direction finding significantly. In this paper, a novel sparse system model for direction of arrival (DOA) estimation in the scenario with gain-phase errors is proposed by exploiting the signal sparsity in the spatial domain. In contrast to the existing sparse-based methods using the grids to construct the dictionary matrix, a novel gridless method based on atomic norm and convex optimization is proposed, where the gain-phase errors are described by a diagonal matrix. With the Schur complement, a semidefinite programming is formulated from the optimization problem, and can be solved efficiently. With the gain-phase errors, the corresponding Cram’er-Rao lower bound (CRLB) of direction finding is derived as an estimation benchmark. Simulation results show that the proposed method performs better than the state-of-the-art methods in the scenario with correlated signals and gain-phase errors. Full article
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Open AccessFeature PaperArticle
Recent Advances in the Processing and Rendering Algorithms for Computer-Generated Holography
Electronics 2019, 8(5), 556; https://doi.org/10.3390/electronics8050556 (registering DOI)
Received: 30 April 2019 / Revised: 10 May 2019 / Accepted: 13 May 2019 / Published: 17 May 2019
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Abstract
Digital holography represents a novel media which promises to revolutionize the way the users interacts with content. This paper presents an in-depth review of the state-of-the-art algorithms for advanced processing and rendering of computer-generated holography. Open-access holographic data are selected and characterized as [...] Read more.
Digital holography represents a novel media which promises to revolutionize the way the users interacts with content. This paper presents an in-depth review of the state-of-the-art algorithms for advanced processing and rendering of computer-generated holography. Open-access holographic data are selected and characterized as references for the experimental analysis. The design of a tool for digital hologram rendering and quality evaluation is presented and implemented as an open-source reference software, with the aim to encourage the approach to the holography research area, and simplify the rendering and quality evaluation tasks. Exploration studies focused on the reproducibility of the results are reported, showing a practical application of the proposed architecture for standardization activities. A final discussion on the results obtained is reported, also highlighting the future developments of the reconstruction software that is made publicly available with this work. Full article
(This article belongs to the Special Issue Digital Media Processing for Immersive Communications)
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Open AccessArticle
A 2.6 ppm/°C 2.5 V Piece-Wise Compensated Bandgap Reference with Low Beta Bipolar
Electronics 2019, 8(5), 555; https://doi.org/10.3390/electronics8050555 (registering DOI)
Received: 17 April 2019 / Revised: 3 May 2019 / Accepted: 5 May 2019 / Published: 17 May 2019
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Abstract
Traditional bandgap reference (BGR) is sensitive to process variation and is not suitable for mass production. Consequently, a stacked piece-wise compensated bandgap reference (SPWBGR) with low beta bipolar is proposed, designed and fabricated in the 0.18 μm high-voltage (HV) BCD process. Two stacked [...] Read more.
Traditional bandgap reference (BGR) is sensitive to process variation and is not suitable for mass production. Consequently, a stacked piece-wise compensated bandgap reference (SPWBGR) with low beta bipolar is proposed, designed and fabricated in the 0.18 μm high-voltage (HV) BCD process. Two stacked BGR (SBGR) cores make up the proposed BGR circuit. Through setting the target reference voltage near the output voltage of SBGR cores, the feedback resistor ratio is reduced and the base current side-effect is significantly decreased. Notably, the SBGR core is implemented by the low beta npn bipolar and it relaxes the requirement for the high beta bipolar. The two SBGR cores are almost identical except for the temperature slope and feedback ratio. The two cores have different zero temperature coefficient (TC) points, one is set at −5 °C, and the other is set at 60 °C, named as SBGRA and SBGRB, respectively. The SBGRA and SBGRB output the same voltage at their zero TC point. The higher voltage of SBGRA and SBGRB is the output voltage. Through the process of tracking the maximum value of different SBGR cores, the proposed SPWBGR achieves 2.6 ppm/°C TC from −40 to 100 °C. As a result, the average TC for five random samples is 5.3 ppm/°C. The line regulation is 2 mV/V from 4.5 to 5.5 V power supply. The current consumption is 6.8 µA. The active area of the proposed BGR is 0.075 mm2. Full article
(This article belongs to the Section Semiconductors and Quantum)
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Open AccessArticle
Data Augmentation Schemes for Deep Learning in an Indoor Positioning Application
Electronics 2019, 8(5), 554; https://doi.org/10.3390/electronics8050554 (registering DOI)
Received: 25 April 2019 / Revised: 11 May 2019 / Accepted: 13 May 2019 / Published: 17 May 2019
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Abstract
In this paper, we propose two data augmentation schemes for deep learning architecture that can be used to directly estimate user location in an indoor environment using mobile phone tracking and electronic fingerprints based on reference points and access points. Using a pretrained [...] Read more.
In this paper, we propose two data augmentation schemes for deep learning architecture that can be used to directly estimate user location in an indoor environment using mobile phone tracking and electronic fingerprints based on reference points and access points. Using a pretrained model, the deep learning approach can significantly reduce data collection time, while the runtime is also significantly reduced. Numerical results indicate that an augmented training database containing seven days’ worth of measurements is sufficient to generate acceptable performance using a pretrained model. Experimental results find that the proposed augmentation schemes can achieve a test accuracy of 89.73% and an average location error that is as low as 2.54 m. Therefore, the proposed schemes demonstrate the feasibility of data augmentation using a deep neural network (DNN)-based indoor localization system that lowers the complexity required for use on mobile devices. Full article
(This article belongs to the Special Issue Indoor Positioning Techniques)
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Open AccessArticle
Wavelet-Integrated Deep Networks for Single Image Super-Resolution
Electronics 2019, 8(5), 553; https://doi.org/10.3390/electronics8050553 (registering DOI)
Received: 25 April 2019 / Revised: 12 May 2019 / Accepted: 14 May 2019 / Published: 17 May 2019
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Abstract
We propose a scale-invariant deep neural network model based on wavelets for single image super-resolution (SISR). The wavelet approximation images and their corresponding wavelet sub-bands across all predefined scale factors are combined to form a big training data set. Then, mappings are determined [...] Read more.
We propose a scale-invariant deep neural network model based on wavelets for single image super-resolution (SISR). The wavelet approximation images and their corresponding wavelet sub-bands across all predefined scale factors are combined to form a big training data set. Then, mappings are determined between the wavelet sub-band images and their corresponding approximation images. Finally, the gradient clipping process is used to boost the training speed of the algorithm. Furthermore, stationary wavelet transform (SWT) is used instead of a discrete wavelet transform (DWT), due to its up-scaling property. In this way, we can preserve more information about the images. In the proposed model, the high-resolution image is recovered with detailed features, due to redundancy (across the scale) property of wavelets. Experimental results show that the proposed model outperforms state-of-the algorithms in terms of peak signal-to-noise ratio (PSNR) and structural similarity index measure (SSIM). Full article
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Open AccessEditorial
Recent Developments in Time-Delay Systems and Their Applications
Electronics 2019, 8(5), 552; https://doi.org/10.3390/electronics8050552 (registering DOI)
Received: 29 April 2019 / Accepted: 9 May 2019 / Published: 17 May 2019
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Abstract
The last few decades have witnessed the rapid development of networked control systems due to their significant advantages and they have been applied to variant industrial areas such as unmanned surface vehicles, unmanned space vehicles, smart grids, wastewater treatment processes, Internet-based teleoperation, intelligent [...] Read more.
The last few decades have witnessed the rapid development of networked control systems due to their significant advantages and they have been applied to variant industrial areas such as unmanned surface vehicles, unmanned space vehicles, smart grids, wastewater treatment processes, Internet-based teleoperation, intelligent transportation systems and so on [...] Full article
(This article belongs to the Special Issue Recent Developments on Time-Delay Systems and Its Applications)
Open AccessFeature PaperArticle
A Compound Current Limiter and Circuit Breaker
Electronics 2019, 8(5), 551; https://doi.org/10.3390/electronics8050551
Received: 18 April 2019 / Revised: 6 May 2019 / Accepted: 7 May 2019 / Published: 16 May 2019
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Abstract
The protection of sensitive loads against voltage drop is a concern for the power system. A fast fault current limiter and circuit breaker can be a solution for rapid voltage recovery of sensitive loads. This paper proposes a compound type of current limiter [...] Read more.
The protection of sensitive loads against voltage drop is a concern for the power system. A fast fault current limiter and circuit breaker can be a solution for rapid voltage recovery of sensitive loads. This paper proposes a compound type of current limiter and circuit breaker (CLCB) which can limit fault current and fast break to adjust voltage sags at the protected buses. In addition, it can act as a circuit breaker to open the faulty line. The proposed CLCB is based on a series L-C resonance, which contains a resonant transformer and a series capacitor bank. Moreover, the CLCB includes two anti-parallel power electronic switches (a diode and an IGBT) connected in series with bus couplers. In order to perform an analysis of CLCB performance, the proposed structure was simulated using MATLAB. In addition, an experimental prototype was built, tested, and the experimental results were reported. Comparisons show that experimental results were in fair agreement with the simulation results and confirm CLCB’s ability to act as a fault current limiter and a circuit breaker. Full article
(This article belongs to the Special Issue Industrial Applications of Power Electronics)
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Open AccessArticle
A Robust Semi-Blind Receiver for Joint Symbol and Channel Parameter Estimation in Multiple-Antenna Systems
Electronics 2019, 8(5), 550; https://doi.org/10.3390/electronics8050550
Received: 9 April 2019 / Revised: 25 April 2019 / Accepted: 8 May 2019 / Published: 16 May 2019
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Abstract
For multiple-antenna systems, the technologies of joint symbol and channel parameter estimation have been developed in recent works. However, existing technologies have a number of problems, such as performance degradation and the large cost of prior information. In this paper, a tensor space-time [...] Read more.
For multiple-antenna systems, the technologies of joint symbol and channel parameter estimation have been developed in recent works. However, existing technologies have a number of problems, such as performance degradation and the large cost of prior information. In this paper, a tensor space-time coding scheme in multiple-antenna systems was considered. This scheme allowed spreading, multiplexing, and allocating information symbols associated with multiple transmitted data streams. We showed that the received signal was formulated as a third-order tensor satisfying a Tucker-2 model, and then a robust semi-blind receiver was developed based on the optimized Levenberg–Marquardt (LM) algorithm. Under the assumption that the instantaneous channel state information (CSI) is unknown at the receiving end, the proposed semi-blind receiver jointly estimates the information symbol and channel parameters efficiently. The proposed receiver had a better estimation performance compared with existing semi-blind receivers, and still performed well when the channel became strongly correlated. Moreover, the proposed semi-blind receiver could be extended to the multi-user massive multiple-input multiple-output (MIMO) system for joint symbol and channel estimation. Computer simulation results were shown to demonstrate the effectiveness of the proposed receiver. Full article
(This article belongs to the Special Issue Multidimensional Digital Signal Processing)
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Open AccessArticle
Dynamic Network Topology Control of Branch-Trimming Robot for Transmission Lines
Electronics 2019, 8(5), 549; https://doi.org/10.3390/electronics8050549
Received: 13 March 2019 / Revised: 2 May 2019 / Accepted: 9 May 2019 / Published: 15 May 2019
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Abstract
With the development of engineering technology, the distributed design-based Branch-Trimming Robot (BTR) has been used to ensure the power supply security of transmission lines. However, it remains difficult to combine distributed BTRs with a wireless sensor network to build an efficient multi-robot system. [...] Read more.
With the development of engineering technology, the distributed design-based Branch-Trimming Robot (BTR) has been used to ensure the power supply security of transmission lines. However, it remains difficult to combine distributed BTRs with a wireless sensor network to build an efficient multi-robot system. To achieve this combination, a dynamic network topology control method was proposed, combining the motion characteristics of robots with the structure of a distributed wireless sensor network. In addition, a topology-updating mechanism based on node signal strength was adopted as well. To achieve efficient data transmission for distributed multi-robot systems, the present study focused on the design of a distributed network model and a dynamic network topology control strategy. Several simulation and test scenarios were implemented, and the changes of network performance under different parameters were studied. Furthermore, the real scene-based dynamic topology control method considers the relationship between network performance and antenna layout. Full article
Open AccessArticle
SHIYF: A Secured and High-Integrity YARN Framework
Electronics 2019, 8(5), 548; https://doi.org/10.3390/electronics8050548
Received: 17 April 2019 / Revised: 7 May 2019 / Accepted: 11 May 2019 / Published: 15 May 2019
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Abstract
Cloud computing is becoming a powerful parallel data processing method, and it can be adopted by many network service providers to build a service framework. Although cloud computing is able to efficiently process a large amount of data, it can be attacked easily [...] Read more.
Cloud computing is becoming a powerful parallel data processing method, and it can be adopted by many network service providers to build a service framework. Although cloud computing is able to efficiently process a large amount of data, it can be attacked easily due to its massively distributed cluster nodes. In this paper, we propose a secure and high-integrity YARN framework (SHIYF), which establishes a close relationship between speculative execution and the security of Yet Another Resource Negotiator (YARN, MapReduce 2.0). SHIYF computes and compares the MD5 hashes of the intermediate and final results in the MapReduce process by launching the speculative executions in a certain ratio, which is able to find actual and potentially malicious nodes in the Hadoop cluster. The prototype of SHIYF is implemented based on Hadoop 2.8.0. In this paper, theoretical derivations and experiments show that SHIYF not only guarantees the security and high integrity of the MapReduce process but also successfully locates the malicious nodes and the potential malicious ones in Hadoop, while increasing overhead slightly. Furthermore, the malicious node detection ratio is more than 87%. Full article
(This article belongs to the Special Issue Cloud Computing and Applications)
Open AccessArticle
Four-Step Current Commutation Strategy for a Matrix Converter Based on Enhanced-PWM MCU Peripherals
Electronics 2019, 8(5), 547; https://doi.org/10.3390/electronics8050547
Received: 9 April 2019 / Revised: 30 April 2019 / Accepted: 9 May 2019 / Published: 15 May 2019
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Abstract
In this paper, an efficient implementation of the four-step current commutation technique for controlling bidirectional power switches in a Matrix Converter (MC) is proposed. This strategy is based on the enhanced pulse width modulation peripheral included in the C2000 Delfino 32-bit microcontroller [...] Read more.
In this paper, an efficient implementation of the four-step current commutation technique for controlling bidirectional power switches in a Matrix Converter (MC) is proposed. This strategy is based on the enhanced pulse width modulation peripheral included in the C 2000 Delfino 32-bit microcontroller of Texas Instruments. By tuning the algorithmic parameters contained in this module, the four-step commutation process is carried out on the Microcontroller Unit (MCU) without overloading the full complex processor and avoiding the use of additional special hardware such as Field-Programmable Gate Arrays (FPGA) or Complex Programmable Logic Devices (CPLD) when controlling the MC. The algorithm is implemented on the TMS320F28379D MCU and operationally validated on an MC prototype, where the functionality of the proposal is demonstrated. Full article
(This article belongs to the Section Power Electronics)
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Open AccessArticle
Load Balancing Scheme for Effectively Supporting Distributed In-Memory Based Computing
Electronics 2019, 8(5), 546; https://doi.org/10.3390/electronics8050546
Received: 16 April 2019 / Revised: 10 May 2019 / Accepted: 13 May 2019 / Published: 15 May 2019
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Abstract
As digital data have increased exponentially due to an increasing number of information channels that create and distribute the data, distributed in-memory systems were introduced to process big data in real-time. However, when the load is concentrated on a specific node in a [...] Read more.
As digital data have increased exponentially due to an increasing number of information channels that create and distribute the data, distributed in-memory systems were introduced to process big data in real-time. However, when the load is concentrated on a specific node in a distributed in-memory environment, the data access performance is degraded, resulting in an overall degradation in the processing performance. In this paper, we propose a new load balancing scheme that performs data migration or replication according to the loading status in heterogeneous distributed in-memory environments. The proposed scheme replicates hot data when the hot data occurs on the node where a load occurs. If the load of the node increases in the absence of hot data, the data is migrated through a hash space adjustment. In addition, when nodes are added or removed, data distribution is performed by adjusting the hash space with the adjacent nodes. The clients store the metadata of the hot data and reduce the access of the load balancer through periodic synchronization. It is confirmed through various performance evaluations that the proposed load balancing scheme improves the overall load balancing performance. Full article
(This article belongs to the Special Issue Cloud Computing and Applications)
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Open AccessFeature PaperArticle
Fence Shaping of Substrate Integrated Fan-Beam Electric Dipole for High-Band 5G
Electronics 2019, 8(5), 545; https://doi.org/10.3390/electronics8050545
Received: 17 April 2019 / Revised: 12 May 2019 / Accepted: 13 May 2019 / Published: 15 May 2019
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Abstract
This work presents fence shaping for dipole antenna operating at 5G high-band frequencies. A via fence is employed around the dipole to suppress back radiation. By varying the geometric shape of the fence, the dipole’s radiation characteristics can be controlled, which adds an [...] Read more.
This work presents fence shaping for dipole antenna operating at 5G high-band frequencies. A via fence is employed around the dipole to suppress back radiation. By varying the geometric shape of the fence, the dipole’s radiation characteristics can be controlled, which adds an additional degree of freedom to the design. This was investigated by studying different fence shapes, namely rectangular-, U-, and V-shaped fences. The wide bandwidth (higher than 6.5 GHz) centered around 28 GHz, and the stable radiation performance from 24 GHz to 32 GHz made the proposed structure capable of supporting multiple 5G frequency bands and the fence shaping help modulate the gain and HPBW of the dipole. All fabricated prototypes attained front-to-back radiation ratio (F/B) higher than 36 dB, with good gain/HPBW performances of 14.1 dBi/103.7°, 13.5dBi/118°, and 12.6 dBi/133° from the V-fence, U-fence, and rectangular fence 4 × 1 arrays, respectively. Full article
(This article belongs to the Special Issue Intelligent Antennas)
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Open AccessArticle
A Range-Division User Relay Selection Scheme and Performance Analysis in NOMA-based Cooperative Opportunistic Multicast Systems
Electronics 2019, 8(5), 544; https://doi.org/10.3390/electronics8050544
Received: 19 April 2019 / Revised: 8 May 2019 / Accepted: 9 May 2019 / Published: 15 May 2019
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Abstract
The original user relay (UR) selection scheme of non-orthogonal multiple access-based cooperative opportunistic multicast scheme, which realizes inter-group cooperation between two multicast groups, ignores the distribution trend of candidate UR in the cell and adopts fixed efficient relay selection range (ERSR) to select [...] Read more.
The original user relay (UR) selection scheme of non-orthogonal multiple access-based cooperative opportunistic multicast scheme, which realizes inter-group cooperation between two multicast groups, ignores the distribution trend of candidate UR in the cell and adopts fixed efficient relay selection range (ERSR) to select UR. It results in high UR selection ratio. Then the coverage efficiency, defined as the ratio of successfully received users to URs, is low. To tackle this problem, a range-division user relay (RDUR) selection scheme is proposed in this paper. Firstly, it divides the circular coverage range of base station into several continuous annular areas (AAs). Secondly, different ERSRs are assigned to unsuccessfully received users in different AAs. Under different ERSR assignments, the performances of UR selection ratio and coverage ratio are analyzed. Lastly, the radius set of ERSR that optimizes system coverage efficiency is used to perform UR selection. From simulation results, with different radius sets, analytical results of UR selection ratio and coverage ratio match well with their simulated ones. It is proved that ERSR allocation affects UR selection ratio and coverage ratio. With RDUR scheme, coverage efficiency increases by at least 14% and capacity efficiency has also been improved. Full article
(This article belongs to the Special Issue Cooperative Communications for Future Wireless Systems)
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Open AccessArticle
Decision-Making System for Lane Change Using Deep Reinforcement Learning in Connected and Automated Driving
Electronics 2019, 8(5), 543; https://doi.org/10.3390/electronics8050543
Received: 4 April 2019 / Revised: 7 May 2019 / Accepted: 10 May 2019 / Published: 14 May 2019
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Abstract
Lane changing systems have consistently received attention in the fields of vehicular communication and autonomous vehicles. In this paper, we propose a lane change system that combines deep reinforcement learning and vehicular communication. A host vehicle, trying to change lanes, receives the state [...] Read more.
Lane changing systems have consistently received attention in the fields of vehicular communication and autonomous vehicles. In this paper, we propose a lane change system that combines deep reinforcement learning and vehicular communication. A host vehicle, trying to change lanes, receives the state information of the host vehicle and a remote vehicle that are both equipped with vehicular communication devices. A deep deterministic policy gradient learning algorithm in the host vehicle determines the high-level action of the host vehicle from the state information. The proposed system learns straight-line driving and collision avoidance actions without vehicle dynamics knowledge. Finally, we consider the update period for the state information from the host and remote vehicles. Full article
(This article belongs to the Special Issue Intelligent Transportation Systems (ITS))
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Open AccessArticle
GA-BP in Thermal Fatigue Failure Prediction of Microelectronic Chips
Electronics 2019, 8(5), 542; https://doi.org/10.3390/electronics8050542
Received: 13 April 2019 / Revised: 8 May 2019 / Accepted: 10 May 2019 / Published: 14 May 2019
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Abstract
A thermal fatigue life prediction model of microelectronic chips based on thermal fatigue tests and solder/substrate interfacial singularity analysis from finite element method (FEM) analysis is established in this paper. To save the calculation of interfacial singular parameters of new chips for life [...] Read more.
A thermal fatigue life prediction model of microelectronic chips based on thermal fatigue tests and solder/substrate interfacial singularity analysis from finite element method (FEM) analysis is established in this paper. To save the calculation of interfacial singular parameters of new chips for life prediction, and improve the accuracy of prediction results in actual applications, a hybrid genetic algorithm–artificial neural network (GA–ANN) strategy is utilized. The proposed algorithm combines the local searching ability of the gradient-based back propagation (BP) strategy with the global searching ability of a genetic algorithm. A series of combinations of the dimensions and thermal mechanical properties of the solder and the corresponding singularity parameters at the failure interface are used to train the proposed GA-BP network. The results of the network, together with the established life prediction model, are used to predict the thermal fatigue lives of new chips. The comparison between the network results and thermal fatigue lives recorded in experiments shows that the GA-BP strategy is a successful prediction technique. Full article
(This article belongs to the Section Microelectronics and Optoelectronics)
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Open AccessArticle
Analysis and Design of an Energy Verification System for SC200 Proton Therapy Facility
Electronics 2019, 8(5), 541; https://doi.org/10.3390/electronics8050541
Received: 23 April 2019 / Revised: 9 May 2019 / Accepted: 10 May 2019 / Published: 13 May 2019
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Abstract
The purpose of this study is to provide an energy verification method for the nozzle of the SC200 proton therapy facility to ensure safe redundancy of treatment. This paper first introduces the composition of the energy selection system of the SC200 proton therapy [...] Read more.
The purpose of this study is to provide an energy verification method for the nozzle of the SC200 proton therapy facility to ensure safe redundancy of treatment. This paper first introduces the composition of the energy selection system of the SC200 proton therapy facility. Secondly, according to IEC60601 standard, the energy verification requirement that correspond to 1 mm error in water is presented. The allowable difference between the measured magnetic field and the reference are calculated based on the energy verification requirements to select the field resolution of the Hall probe. To ensure accuracy and stability, two Hall probes are mounted on the dipole to monitor the magnetic field strength to verify the proton beam energy in real time. In addition, the test results of the residual field of the dipole show that the probe system meets the accuracy requirements of energy verification. Furthermore, the maximum width of the slit of the energy selection system in accordance with the IEC standard at the corresponding energy is calculated and compared with the actual position of the movable slit to verify the momentum divergence of the proton beam. Finally, we present an energy verification method. Full article
(This article belongs to the Special Issue Applications of Electromagnetic Waves)
Open AccessArticle
Congestion Control in V2V Safety Communication: Problem, Analysis, Approaches
Electronics 2019, 8(5), 540; https://doi.org/10.3390/electronics8050540
Received: 26 January 2019 / Revised: 25 March 2019 / Accepted: 27 March 2019 / Published: 13 May 2019
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Abstract
The emergence of Vehicular Ad Hoc Networks (VANETs) is expected to be an important step toward achieving safety and efficiency in intelligent transportation systems (ITS). One important requirement of safety applications is that vehicles are able to communicate with neighboring vehicles, with very [...] Read more.
The emergence of Vehicular Ad Hoc Networks (VANETs) is expected to be an important step toward achieving safety and efficiency in intelligent transportation systems (ITS). One important requirement of safety applications is that vehicles are able to communicate with neighboring vehicles, with very low latency and packet loss. The high mobility, unreliable channel quality and high message rates make this a challenging problem for VANETs. There have been significant research activities in recent years in the development of congestion control algorithms that ensure reliable delivery of safety messages in vehicle-to-vehicle (V2V) communication. In this paper, we present a comprehensive survey of congestion control approaches for VANET. We identify the relevant parameters and performance metrics that can be used to evaluate these approaches and analyze each approach based a number of factors such as the type of traffic, whether it is proactive or reactive, and the mechanism for controlling congestion. We conclude this paper with some additional considerations for designing V2V communication protocols and interesting and open research problems and directions for future work. Full article
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Open AccessArticle
Fuzzy System and Time Window Applied to Traffic Service Network Problems under a Multi-Demand Random Network
Electronics 2019, 8(5), 539; https://doi.org/10.3390/electronics8050539
Received: 19 April 2019 / Revised: 9 May 2019 / Accepted: 10 May 2019 / Published: 13 May 2019
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Abstract
The transportation network promotes key human development links such as social production, population movement and resource exchange. As cities continue to expand, transportation networks become increasingly complex. A bad traffic network design will affect the quality of urban development and cause regional economic [...] Read more.
The transportation network promotes key human development links such as social production, population movement and resource exchange. As cities continue to expand, transportation networks become increasingly complex. A bad traffic network design will affect the quality of urban development and cause regional economic losses. How to plan transportation routes and allocate transportation resources is an important issue in today’s society. This study uses the network reliability method to solve traffic network problems. Network reliability refers to the probability of a successful connection between the source and sink nodes in the network. There are many systems in the world that use network architecture; therefore, network reliability is widely used in various practical problems and cases. In the past, some scholars have used network reliability to solve traffic service network problems. However, the processing of time is not detailed enough to fully express the real user’s time requirements and does not consider that the route traffic will affect the reliability of the entire network. This study improves on past network reliability methods by using a fuzzy system and a time window to construct a network model. Using the concept of fuzzy systems, according to past experience, data or expert predictions to define the degree of flow, time and reliability, can also determine the relationship between these factors. The time window can be adjusted according to the time limit in reality, reaching the limit of the complete expression time. In addition, the network reliability algorithm used in this study is a direct algorithm. Compared with the past indirect algorithms, the computation time is greatly reduced and complex problems can be solved more efficiently. Full article
(This article belongs to the Special Issue Vehicular Networks and Communications)
Open AccessArticle
Effect of lateral Gate Design on the Performance of Junctionless Lateral Gate Transistors
Electronics 2019, 8(5), 538; https://doi.org/10.3390/electronics8050538
Received: 12 March 2019 / Revised: 2 April 2019 / Accepted: 2 April 2019 / Published: 13 May 2019
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Abstract
In this paper, we investigate the effect of lateral gate design on performance of a p-type double lateral gate junctionless transistors (DGJLTs) with an air gate gap. The impact of lateral gate length, which modifies the real channel length of the device and [...] Read more.
In this paper, we investigate the effect of lateral gate design on performance of a p-type double lateral gate junctionless transistors (DGJLTs) with an air gate gap. The impact of lateral gate length, which modifies the real channel length of the device and gate gap variation down to 50 nm which have been found to be the most influential factors in the performance of the device have been comprehensively investigated. The characteristics are demonstrated and compared with a nominal DGJLTs through three-dimensional technology computer-aided design (TCAD) simulation. At constant channel geometry (thickness and width), when the lateral gate length decreases, the results show constant flatband drain current characteristics while the OFF state current (IOFF) increases significantly. On the other hand, by decreasing the air gap the subthreshold current considerably decreases while the flatband current is constant. Moreover, at a certain gate gap, the gates lose control over the channel and the device simply works as a resistor. Electric field component, carriers’ density, band edge energies, and recombination rate of the carriers inside the channel in depletion and accumulation regimes are analysed to interpret the variation of output characteristics. Full article
(This article belongs to the Section Semiconductors and Quantum)
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Open AccessArticle
A CMOS W-Band Amplifier with Tunable Neutralization Using a Cross-Coupled MOS–varactor Pair
Electronics 2019, 8(5), 537; https://doi.org/10.3390/electronics8050537
Received: 21 March 2019 / Revised: 27 April 2019 / Accepted: 10 May 2019 / Published: 13 May 2019
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Abstract
This paper presents a CMOS W-band amplifier adopting a novel neutralization technique for high gain and stability. The W-band amplifier consists of four common-source differential gain cells that are neutralized by a cross-coupled MOS–varactor pair. Contrary to conventional neutralizations, the proposed technique enables [...] Read more.
This paper presents a CMOS W-band amplifier adopting a novel neutralization technique for high gain and stability. The W-band amplifier consists of four common-source differential gain cells that are neutralized by a cross-coupled MOS–varactor pair. Contrary to conventional neutralizations, the proposed technique enables tunable neutralization, so that the gate-to-drain capacitance of transistors is accurately tracked and neutralized as the varactor voltage is adjusted. This makes the neutralization tolerant of capacitance change caused by process–voltage–temperature (PVT) variation or transistor model inaccuracy, which commonly occurs at mm-wave frequencies. The proposed tunable neutralization is experimentally confirmed by measuring gain and stability of the W-band amplifier fabricated in a 65-nm CMOS process. The amplifier achieves a measured gain of 17.5 dB at 79 GHz and a 3-dB bandwidth from 77.5 to 84 GHz without any stability issue. The DC power consumption is 56.7 mW and the chip area is 0.85 mm2. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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Open AccessArticle
Chaotic Pattern Array for Single-Pixel Imaging
Electronics 2019, 8(5), 536; https://doi.org/10.3390/electronics8050536
Received: 25 March 2019 / Revised: 7 May 2019 / Accepted: 8 May 2019 / Published: 13 May 2019
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Abstract
Single-pixel imaging (SPI) is an emerging framework that can capture the image of a scene via a single-point detector at a considerably low cost. It measures the projection at the detector of the scene under view with certain patterns. One can reconstruct the [...] Read more.
Single-pixel imaging (SPI) is an emerging framework that can capture the image of a scene via a single-point detector at a considerably low cost. It measures the projection at the detector of the scene under view with certain patterns. One can reconstruct the image of the scene via post-processing the measurements modulated by the patterns. However, the most commonly-used random patterns are not always desirable in many applications, especially for real-time, resource-limited occasions, due to their high memory requirement and huge cost in software and hardware implementation. In this paper, a chaotic pattern array is proposed for the SPI architecture. Compared with random patterns, the proposed chaotic pattern array can not only promise to increase the capabilities of the SPI device, but can also reduce the memory cost and complexity of hardware implementation in the meantime. Moreover, convincing experiment results are given to illustrate that the proposed pattern array is suitable for single-pixel cameras, as well as other compressive imaging applications. Full article
(This article belongs to the Section Circuit and Signal Processing)
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Open AccessArticle
A Novel Multi-Input Bidirectional LSTM and HMM Based Approach for Target Recognition from Multi-Domain Radar Range Profiles
Electronics 2019, 8(5), 535; https://doi.org/10.3390/electronics8050535
Received: 4 April 2019 / Revised: 4 May 2019 / Accepted: 8 May 2019 / Published: 13 May 2019
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Abstract
Radars, as active detection sensors, are known to play an important role in various intelligent devices. Target recognition based on high-resolution range profile (HRRP) is an important approach for radars to monitor interesting targets. Traditional recognition algorithms usually rely on a single feature, [...] Read more.
Radars, as active detection sensors, are known to play an important role in various intelligent devices. Target recognition based on high-resolution range profile (HRRP) is an important approach for radars to monitor interesting targets. Traditional recognition algorithms usually rely on a single feature, which makes it difficult to maintain the recognition performance. In this paper, 2-D sequence features from HRRP are extracted in various data domains such as time-frequency domain, time domain, and frequency domain. A novel target identification method is then proposed, by combining bidirectional Long Short-Term Memory (BLSTM) and a Hidden Markov Model (HMM), to learn these multi-domain sequence features. Specifically, we first extract multi-domain HRRP sequences. Next, a new multi-input BLSTM is proposed to learn these multi-domain HRRP sequences, which are then fed to a standard HMM classifier to learn multi-aspect features. Finally, the trained HMM is used to implement the recognition task. Extensive experiments are carried out on the publicly accessible, benchmark MSTAR database. Our proposed algorithm is shown to achieve an identification accuracy of over 91% with a lower false alarm rate and higher identification confidence, compared to several state-of-the-art techniques. Full article
(This article belongs to the Special Issue Radar Sensor for Motion Sensing and Automobile)
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Open AccessArticle
Enabling Green Wireless Sensor Networks: Energy Efficient T-MAC Using Markov Chain Based Optimization
Electronics 2019, 8(5), 534; https://doi.org/10.3390/electronics8050534
Received: 18 April 2019 / Revised: 5 May 2019 / Accepted: 8 May 2019 / Published: 13 May 2019
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Abstract
Due to the rapidly growing sensor-enabled connected world around us, with the continuously decreasing size of sensors from smaller to tiny, energy efficiency in wireless sensor networks has drawn ample consideration in both academia as well as in industries’ R&D. The literature of [...] Read more.
Due to the rapidly growing sensor-enabled connected world around us, with the continuously decreasing size of sensors from smaller to tiny, energy efficiency in wireless sensor networks has drawn ample consideration in both academia as well as in industries’ R&D. The literature of energy efficiency in wireless sensor networks (WSNs) is focused on the three layers of wireless communication, namely the physical, Medium Access Control (MAC) and network layers. Physical layer-centric energy efficiency techniques have limited capabilities due to hardware designs and size considerations. Network layer-centric energy efficiency approaches have been constrained, in view of network dynamics and available network infrastructures. However, energy efficiency at the MAC layer requires a traffic cooperative transmission control. In this context, this paper presents a one-dimensional discrete-time Markov chain analytical model of the Timeout Medium Access Control (T-MAC) protocol. Specifically, an analytical model is derived for T-MAC focusing on an analysis of service delay, throughput, energy consumption and power efficiency under unsaturated traffic conditions. The service delay model calculates the average service delay using the adaptive sleep wakeup schedules. The component models include a queuing theory-based throughput analysis model, a cycle probability-based analytical model for computing the probabilities of a successful transmission, collision, and the idle state of a sensor, as well as an energy consumption model for the sensor’s life cycle. A fair performance assessment of the proposed T-MAC analytical model attests to the energy efficiency of the model when compared to that of state-of-the-art techniques, in terms of better power saving, a higher throughput and a lower energy consumption under various traffic loads. Full article
(This article belongs to the Special Issue Vehicular Networks and Communications)
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Open AccessArticle
Regularized Auto-Encoder-Based Separation of Defects from Backgrounds for Inspecting Display Devices
Electronics 2019, 8(5), 533; https://doi.org/10.3390/electronics8050533
Received: 1 April 2019 / Revised: 6 May 2019 / Accepted: 8 May 2019 / Published: 12 May 2019
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Abstract
We investigated a novel method for separating defects from the background for inspecting display devices. Separation of defects has important applications such as determining whether the detected defects are truly defective and the quantification of the degree of defectiveness. Although many studies on [...] Read more.
We investigated a novel method for separating defects from the background for inspecting display devices. Separation of defects has important applications such as determining whether the detected defects are truly defective and the quantification of the degree of defectiveness. Although many studies on estimating patterned background have been conducted, the existing studies are mainly based on the approach of approximation by low-rank matrices. Because the conventional methods face problems such as imperfect reconstruction and difficulty of selecting the bases for low-rank approximation, we have studied a deep-learning-based foreground reconstruction method that is based on the auto-encoder structure with a regression layer for the output. In the experimental studies carried out using mobile display panels, the proposed method showed significantly improved performance compared to the existing singular value decomposition method. We believe that the proposed method could be useful not only for inspecting display devices but also for many applications that involve the detection of defects in the presence of a textured background. Full article
(This article belongs to the Section Computer Science & Engineering)
Open AccessArticle
Considerations Regarding the Design of a Minimum Variance Control System for an Induction Generator
Electronics 2019, 8(5), 532; https://doi.org/10.3390/electronics8050532
Received: 16 April 2019 / Revised: 8 May 2019 / Accepted: 9 May 2019 / Published: 11 May 2019
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Abstract
This paper presents a comparative analysis regarding a self-tuning minimum variance control system of a double-fed induction generator with load and connected to a power system through a long transmission line. A new complex nonlinear model describing this relationship between the induction generator, [...] Read more.
This paper presents a comparative analysis regarding a self-tuning minimum variance control system of a double-fed induction generator with load and connected to a power system through a long transmission line. A new complex nonlinear model describing this relationship between the induction generator, electrical consumer, transmission line, and power system is designed and implemented to simulate the controlled plant behavior. Starting from a simplified linear model of this complex plant, obtained through linearization of its nonlinear model around an operating point, the minimum variance control law design is performed by minimizing a cost criterion function. The main goal and also the paper novelty consists of the identification of a minimum order of this linearized model used to design a reduced order control law, which can still provide good control performance. Full article
(This article belongs to the Section Power Electronics)
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Open AccessArticle
Radiation Properties of Conformal Antennas: The Elliptical Source
Electronics 2019, 8(5), 531; https://doi.org/10.3390/electronics8050531
Received: 8 April 2019 / Revised: 2 May 2019 / Accepted: 9 May 2019 / Published: 11 May 2019
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Abstract
The solution of inverse source problems by numerical procedures requires the investigation of the number of independent pieces of information that can be reconstructed stably. To this end, the mathematical properties of the relevant operators are to be examined in connection with the [...] Read more.
The solution of inverse source problems by numerical procedures requires the investigation of the number of independent pieces of information that can be reconstructed stably. To this end, the mathematical properties of the relevant operators are to be examined in connection with the source shape. The aim of this work is to investigate the effect of the source shape on the eigendecomposition of the radiation operator in a 2D geometry, when the radiated field is observed over a semi-circumference in the far zone. We examine both the behavior of the eigenvalues and the effect of the choice of the representation variables on the point spread function (PSF). In particular, the effect of the choice of the representation variables is considered since operator properties may depend on it. We analyze different source shapes evolving from a line to a semi-ellipse and, finally, to a semi-circumference, in order to understand how the increase of the source aspect ratio affects the results. The main conclusions concern an estimate of the number of degrees of freedom in connection with the source geometry and the fact that the PSF exhibits the same variant behavior along the considered domain, independently of the observation variable. The practical relevance of the result is illustrated by two numerical examples. The first one deals with the conformal array diagnostics for the reliable reconstruction of the excitation of the array elements. The second one concerns the array synthesis problem, and a comparison between the radiating performances of the source geometries is presented. Full article
(This article belongs to the Special Issue Microwave Imaging and Its Application)
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Open AccessArticle
A Novel Audio Encryption Algorithm with Permutation-Substitution Architecture
Electronics 2019, 8(5), 530; https://doi.org/10.3390/electronics8050530
Received: 7 April 2019 / Revised: 4 May 2019 / Accepted: 6 May 2019 / Published: 11 May 2019
Viewed by 205 | PDF Full-text (1976 KB)
Abstract
In this paper, a new cryptographic method is proposed, designed for audio files’ security. The encryption algorithm is based on classic symmetric models using pseudo-random number generator composed with chaotic circle map and modified rotation equations. The scheme of a new pseudo-random generator [...] Read more.
In this paper, a new cryptographic method is proposed, designed for audio files’ security. The encryption algorithm is based on classic symmetric models using pseudo-random number generator composed with chaotic circle map and modified rotation equations. The scheme of a new pseudo-random generator is presented and used as basis for chaotic bit-level permutations and substitutions applied to audio files structure for successful encryption. The audio encryption and decryption algorithms are described and explained. Proving the high level of security we provide extensive cryptographic analysis including key sensitivity analysis, key-space analysis, waveform and spectrogram analysis, correlation analysis, number of sample change rate analysis, level of noise analysis and speed performance test. Full article
(This article belongs to the Section Computer Science & Engineering)
Open AccessArticle
Design of a 41.14–48.11 GHz Triple Frequency Based VCO
Electronics 2019, 8(5), 529; https://doi.org/10.3390/electronics8050529
Received: 12 April 2019 / Revised: 5 May 2019 / Accepted: 7 May 2019 / Published: 11 May 2019
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Abstract
Growing deployment of more efficient communication systems serving electric power grids highlights the importance of designing more advanced intelligent electronic devices and communication-enabled measurement units. In this context, phasor measurement units (PMUs) are being widely deployed in power systems. A common block in [...] Read more.
Growing deployment of more efficient communication systems serving electric power grids highlights the importance of designing more advanced intelligent electronic devices and communication-enabled measurement units. In this context, phasor measurement units (PMUs) are being widely deployed in power systems. A common block in almost all PMUs is a phase locked oscillator which uses a voltage controlled oscillator (VCO). In this paper, a triple frequency based voltage controlled oscillator is presented with low phase noise and robust start-up. The VCO consists of a detector, a comparator, and triple frequency. A VCO starts-up in class AB, then steadies oscillation in class C with low current oscillation. The frequency of the VCO, which is from 13.17 GHz to 16.03 GHz, shows that the frequency is tripling to 41.14–48.11 GHz. Therefore, its application is not limited to PMUs. This work has been simulated in a standard 0.18 µm CMOS process. The simulated VCO achieves a phase noise of −99.47 dBc/Hz at 1 MHz offset and −121.8 dBc/Hz at 10 MHz offset from the 48.11 GHz carrier. Full article
(This article belongs to the Section Circuit and Signal Processing)
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