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Electronics, Volume 7, Issue 11 (November 2018) – 74 articles

Cover Story (view full-size image): Sensing services for detecting humans and animals by analyzing the environmental changes of WLAN signals have attracted attention in recent years. In object detection using WLAN signals, a widely known technique is to use the time changes in RSSI that are easily measured between WLAN devices. Utilizing channel responses including power and phase values per subcarrier on MIMO-OFDM transmission has been researched as channel state information (CSI) to further improve detection accuracy. View this paper.
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23 pages, 1111 KiB  
Article
Sparse DOD/DOA Estimation in a Bistatic MIMO Radar With Mutual Coupling Effect
by Peng Chen, Zhenxin Cao, Zhimin Chen and Chunhua Yu
Electronics 2018, 7(11), 341; https://doi.org/10.3390/electronics7110341 - 21 Nov 2018
Cited by 22 | Viewed by 3812
Abstract
The unknown mutual coupling effect between antennas significantly degrades the target localization performance in the bistatic multiple-input multiple-output (MIMO) radar. In this paper, the joint estimation problem for the direction of departure (DOD) and direction of arrival (DOA) is addressed. By exploiting the [...] Read more.
The unknown mutual coupling effect between antennas significantly degrades the target localization performance in the bistatic multiple-input multiple-output (MIMO) radar. In this paper, the joint estimation problem for the direction of departure (DOD) and direction of arrival (DOA) is addressed. By exploiting the target sparsity in the spatial domain and formulating a dictionary matrix with discretizing the DOD/DOA into grids, compressed sensing (CS)-based system model is given. However, in the practical MIMO radar systems, the target cannot be precisely on the grids, and the unknown mutual coupling effect degrades the estimation performance. Therefore, a novel CS-based DOD/DOA estimation model with both the off-grid and mutual coupling effect is proposed, and a novel sparse reconstruction method is proposed to estimate DOD/DOA with updating both the off-grid and mutual coupling parameters iteratively. Moreover, to describe the estimation performance, the corresponding Cramér–Rao lower bounds (CRLBs) with all the unknown parameters are theoretically derived. Simulation results show that the proposed method can improve the DOD/DOA estimation in the scenario with unknown mutual coupling effect, and outperform state-of-the-art methods. Full article
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20 pages, 4904 KiB  
Article
Virtual Inertia-Based Control Strategy of Two-Stage Photovoltaic Inverters for Frequency Support in Islanded Micro-Grid
by Xin Huang, Keyou Wang, Guojie Li and Hua Zhang
Electronics 2018, 7(11), 340; https://doi.org/10.3390/electronics7110340 - 21 Nov 2018
Cited by 22 | Viewed by 4917
Abstract
For an islanded micro-grid with a high penetration of photovoltaic (PV) power generators, the low inertia reserve and the maximum peak power tracking control may increase the difficulty of maintaining the system’s supply–demand balance, and cause frequency instability, especially when the available generation [...] Read more.
For an islanded micro-grid with a high penetration of photovoltaic (PV) power generators, the low inertia reserve and the maximum peak power tracking control may increase the difficulty of maintaining the system’s supply–demand balance, and cause frequency instability, especially when the available generation is excessive. This will require changes in the way the PV inverter is controlled. In this paper, a virtual inertia frequency control (VIFC) strategy is proposed to let the two-stage PV inverters emulate inertia and support the system frequency with a timely response (e.g., inertia response), and the required power for inertia emulation is obtained from both the DC-link capacitor and the PV reserved energy. As the rate of the system frequency change can be reduced with the inertia increase, the proposed method can mitigate the frequency contingency event before the superior-level coordination control is enabled for the frequency restoration. The simulation results demonstrate the effectiveness of the proposed method. Full article
(This article belongs to the Special Issue Grid Connected Photovoltaic Systems)
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15 pages, 825 KiB  
Article
Robust DC-Link Voltage Tracking Controller with Variable Control Gain for Permanent Magnet Synchronous Generators
by Seok-Kyoon Kim and Kyo-Beum Lee
Electronics 2018, 7(11), 339; https://doi.org/10.3390/electronics7110339 - 21 Nov 2018
Cited by 3 | Viewed by 3294
Abstract
This study develops a robust DC-link voltage tracking controller with variable control gain for permanent magnet synchronous generators. The first feature is to suggest an auto-tuning algorithm to drive the control gain to update the closed-loop cut-off frequency. The second one is to [...] Read more.
This study develops a robust DC-link voltage tracking controller with variable control gain for permanent magnet synchronous generators. The first feature is to suggest an auto-tuning algorithm to drive the control gain to update the closed-loop cut-off frequency. The second one is to prove that the proposed controller incorporating auto-tuner and disturbance observer (DOB) coerces the closed-loop system to achieve the desired voltage tracking behavior, exponentially, with the steady-state rejection property. The control performance is demonstrated by emulating a wind-turbine power system using the powerSIM (PSIM) software. Full article
(This article belongs to the Special Issue Applications of Power Electronics)
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13 pages, 315 KiB  
Article
Coordinated Multicast Precoding for Multi-Cell Massive MIMO Transmission Exploiting Statistical Channel State Information
by Li You, Xu Chen, Wenjin Wang and Xiqi Gao
Electronics 2018, 7(11), 338; https://doi.org/10.3390/electronics7110338 - 20 Nov 2018
Cited by 4 | Viewed by 3054
Abstract
This paper considers coordinated multi-cell multicast precoding for massive multiple-input-multiple-output transmission where only statistical channel state information of all user terminals (UTs) in the coordinated network is known at the base stations (BSs). We adopt the sum of the achievable ergodic multicast rate [...] Read more.
This paper considers coordinated multi-cell multicast precoding for massive multiple-input-multiple-output transmission where only statistical channel state information of all user terminals (UTs) in the coordinated network is known at the base stations (BSs). We adopt the sum of the achievable ergodic multicast rate as the design objective. We first show the optimal closed-form multicast signalling directions of each BS, which simplifies the coordinated multicast precoding problem into a coordinated beam domain power allocation problem. Via invoking the minorization-maximization framework, we then propose an iterative power allocation algorithm with guaranteed convergence to a stationary point. In addition, we derive the deterministic equivalent of the design objective to further reduce the optimization complexity via invoking the large-dimensional random matrix theory. Numerical results demonstrate the performance gain of the proposed coordinated approach over the conventional uncoordinated approach, especially for cell-edge UTs. Full article
(This article belongs to the Special Issue Green Communications in Smart City)
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31 pages, 11253 KiB  
Article
Development of a Bike-Sharing System Based on Pedal-Assisted Electric Bicycles for Bogota City
by David Florez, Henry Carrillo, Ricardo Gonzalez, Max Herrera, Ronald Hurtado-Velasco, Martha Cano, Sergio Roa and Tatiana Manrique
Electronics 2018, 7(11), 337; https://doi.org/10.3390/electronics7110337 - 20 Nov 2018
Cited by 10 | Viewed by 8321
Abstract
The lack of sustainable solutions to mobility and transportation is a major problem in Latin American cities and requires prompt solutions. The main issues in Latin America are the high-cost of solutions, no inclusion of renewable energies, poor energy management, the use of [...] Read more.
The lack of sustainable solutions to mobility and transportation is a major problem in Latin American cities and requires prompt solutions. The main issues in Latin America are the high-cost of solutions, no inclusion of renewable energies, poor energy management, the use of foreign systems not adapted to local contexts, ineffective regional legislation and politics, among others. In this paper the main technical issues concerning the implementation of a bike-sharing system using pedaling-assisted (PAS) electric bicycles for Bogota City are discussed and a solution is proposed. To solve such problems, a methodology to design a tailored solution well suited to Bogota citizen’s needs is developed. Such methodology starts with the development of an on-board-computer (OBC) in order to characterize bike-users by collecting a rider’s data in real-time. Furthermore, the proposed solution develops a low-cost middle-drive (mid-drive) propulsion system for the PAS in the electric bike using brushless-DC (BLDC) motors and by implementing a field-oriented controller (FOC). The reported bike-sharing system also includes the development and implementation of two charging-stations that enable charging the battery on the electric bikes exclusively by using photovoltaic energy. Experimental results are presented and discussed. Full article
(This article belongs to the Special Issue Green Communications in Smart City)
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20 pages, 16241 KiB  
Article
Illumination-Insensitive Skin Depth Estimation from a Light-Field Camera Based on CGANs toward Haptic Palpation
by Myeongseob Ko, Donghyun Kim, Mingi Kim and Kwangtaek Kim
Electronics 2018, 7(11), 336; https://doi.org/10.3390/electronics7110336 - 20 Nov 2018
Cited by 6 | Viewed by 3949
Abstract
A depth estimation has been widely studied with the emergence of a Lytro camera. However, skin depth estimation using a Lytro camera is too sensitive to the influence of illumination due to its low image quality, and thus, when three-dimensional reconstruction is attempted, [...] Read more.
A depth estimation has been widely studied with the emergence of a Lytro camera. However, skin depth estimation using a Lytro camera is too sensitive to the influence of illumination due to its low image quality, and thus, when three-dimensional reconstruction is attempted, there are limitations in that either the skin texture information is not properly expressed or considerable numbers of errors occur in the reconstructed shape. To address these issues, we propose a method that enhances the texture information and generates robust images unsusceptible to illumination using a deep learning method, conditional generative adversarial networks (CGANs), in order to estimate the depth of the skin surface more accurately. Because it is difficult to estimate the depth of wrinkles with very few characteristics, we have built two cost volumes using the difference of the pixel intensity and gradient, in two ways. Furthermore, we demonstrated that our method could generate a skin depth map more precisely by preserving the skin texture effectively, as well as by reducing the noise of the final depth map through the final depth-refinement step (CGAN guidance image filtering) to converge into a haptic interface that is sensitive to the small surface noise. Full article
(This article belongs to the Section Computer Science & Engineering)
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21 pages, 2279 KiB  
Article
Coordination of Congestion and Awareness Control in Vehicular Networks
by Miguel Sepulcre and Javier Gozalvez
Electronics 2018, 7(11), 335; https://doi.org/10.3390/electronics7110335 - 20 Nov 2018
Cited by 10 | Viewed by 3612
Abstract
Vehicular networks need to guarantee the communication reliability levels necessary to satisfy the application requirements, while ensuring a stable network operation even under dense deployments. To this aim, congestion and awareness control protocols dynamically adapt the same communication parameters based on context conditions. [...] Read more.
Vehicular networks need to guarantee the communication reliability levels necessary to satisfy the application requirements, while ensuring a stable network operation even under dense deployments. To this aim, congestion and awareness control protocols dynamically adapt the same communication parameters based on context conditions. If the two protocols operate independently, negative interactions or conflicts can arise. This situation can occur if for example congestion control requires decreasing the transmission power to reduce the channel load, but this reduction negatively influences the vehicles’ awareness range. To address these interactions or conflicts, this paper proposes and evaluates a methodology to coordinate congestion and awareness control protocols. A key advantage of the proposed methodology is that it does not require the integration of the interacting protocols, nor does it require changing their original design. The obtained results demonstrate the effectiveness of the proposed coordination methodology. In addition, the proposed methodology can be extended to the coordination of multiple protocols operating over the same communication parameters. This is here demonstrated considering the coordination of congestion, awareness and topology control protocols. Full article
(This article belongs to the Special Issue Smart, Connected and Efficient Transportation Systems)
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20 pages, 6279 KiB  
Article
A Bidirectional Double Uneven Power Converter Based DC–DC Converter for Solid-State Transformers
by Kiwoo Park and Kyo-Beum Lee
Electronics 2018, 7(11), 334; https://doi.org/10.3390/electronics7110334 - 19 Nov 2018
Cited by 4 | Viewed by 4139
Abstract
This paper presents a novel bidirectional double uneven power (BiDUP) based dc-dc converter and its design and control methods. The proposed converter utilizes two dual active bridge (DAB) converters with different power ratings in a special way to realize zero current switching (ZCS), [...] Read more.
This paper presents a novel bidirectional double uneven power (BiDUP) based dc-dc converter and its design and control methods. The proposed converter utilizes two dual active bridge (DAB) converters with different power ratings in a special way to realize zero current switching (ZCS), where both turn-on and turn-off switchings occur under the zero-current condition. A design example of the proposed BiDUP converter is presented for medium voltage (MV) and high-power solid-state transformer (SST) systems where both voltage transformation and bidirectional power flow are required. The main features of the proposed converter are to reduce both the switching losses in power semiconductor devices and the filter inductance requirement simultaneously. To verify the feasibility of the proposed converter, a simulation study on the BiDUP converter based SST in a distribution system is presented. Furthermore, to validate the operational principle of the proposed converter, an experimental study using a small-scale prototype is also presented. Full article
(This article belongs to the Special Issue Renewable Electric Energy Systems)
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13 pages, 2648 KiB  
Article
Modelling of the Power Interface of the Digital-Physical Hybrid Simulation System of a VSC-HVDC Based on Virtual Resistance Compensation
by Jian Le, Hao Zhang, Cao Wang, Xingrui Li and Jiangfeng Zhu
Electronics 2018, 7(11), 333; https://doi.org/10.3390/electronics7110333 - 19 Nov 2018
Cited by 1 | Viewed by 2815
Abstract
To enhance the stability and accuracy of the digital-physical hybrid simulation system of a modular multilevel converter-based high voltage direct current (MMC-HVDC) system, this paper presents an improved power interface modeling algorithm based on ideal transformer method (ITM). By analyzing the stability condition [...] Read more.
To enhance the stability and accuracy of the digital-physical hybrid simulation system of a modular multilevel converter-based high voltage direct current (MMC-HVDC) system, this paper presents an improved power interface modeling algorithm based on ideal transformer method (ITM). By analyzing the stability condition of a hybrid simulation system based on the ITM model, the current of a so-called virtual resistance is added to the control signal of the controlled current source in the digital subsystem, and the stability of the hybrid simulation system with the improved power interface model is analyzed. The value of the virtual resistance is optimized by comprehensively considering system stability and simulation precision. A two-terminal bipolar MMC-HVDC simulation system based on the proposed power interface model is established. The comparisons of the simulation results verify that the proposed method can effectively improve the stability of the hybrid simulation system, and at the same time has the advantages of high simulation accuracy and easy implementation. Full article
(This article belongs to the Section Power Electronics)
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18 pages, 4353 KiB  
Article
HLS Based Approach to Develop an Implementable HDR Algorithm
by Rappy Saha, Partha Pratim Banik and Ki-Doo Kim
Electronics 2018, 7(11), 332; https://doi.org/10.3390/electronics7110332 - 19 Nov 2018
Cited by 2 | Viewed by 4089
Abstract
Hardware suitability of an algorithm can only be verified when the algorithm is actually implemented in the hardware. By hardware, we indicate system on chip (SoC) where both processor and field-programmable gate array (FPGA) are available. Our goal is to develop a simple [...] Read more.
Hardware suitability of an algorithm can only be verified when the algorithm is actually implemented in the hardware. By hardware, we indicate system on chip (SoC) where both processor and field-programmable gate array (FPGA) are available. Our goal is to develop a simple algorithm that can be implemented on hardware where high-level synthesis (HLS) will reduce the tiresome work of manual hardware description language (HDL) optimization. We propose an algorithm to achieve high dynamic range (HDR) image from a single low dynamic range (LDR) image. We use highlight removal technique for this purpose. Our target is to develop parameter free simple algorithm that can be easily implemented on hardware. For this purpose, we use statistical information of the image. While software development is verified with state of the art, the HLS approach confirms that the proposed algorithm is implementable to hardware. The performance of the algorithm is measured using four no-reference metrics. According to the measurement of the structural similarity (SSIM) index metric and peak signal-to-noise ratio (PSNR), hardware simulated output is at least 98.87 percent and 39.90 dB similar to the software simulated output. Our approach is novel and effective in the development of hardware implementable HDR algorithm from a single LDR image using the HLS tool. Full article
(This article belongs to the Section Computer Science & Engineering)
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17 pages, 6725 KiB  
Article
Improved Voltage Drop Compensation Method for Hybrid Fuel Cell Battery System
by Tae-Ho Eom, Jin-Wook Kang, Jintae Kim, Min-Ho Shin, Jung-Hyo Lee and Chung-Yuen Won
Electronics 2018, 7(11), 331; https://doi.org/10.3390/electronics7110331 - 17 Nov 2018
Cited by 7 | Viewed by 5803
Abstract
In this paper, a voltage drop compensation method for hybrid hydrogen fuel cell battery system, with a hydrogen recirculation powering a forklift, is studied. During recirculating hydrogen fuel to recycle hydrogen that has not reacted enough at the system, impurities can be mixed [...] Read more.
In this paper, a voltage drop compensation method for hybrid hydrogen fuel cell battery system, with a hydrogen recirculation powering a forklift, is studied. During recirculating hydrogen fuel to recycle hydrogen that has not reacted enough at the system, impurities can be mixed with the hydrogen fuel. This leads to low hydrogen concentration and a drop in the output voltage of the fuel cell system. In excessive voltage drop, the fuel cell system can be shutdown. This paper proposes a voltage drop compensation method using an electrical control algorithm to prevent system shutdown by reducing voltage drop. Technically, voltage drop is typically caused by three kinds of factors: (1) The amount of pure hydrogen supply; (2) the temperature of fuel cell stacks; and (3) the current density to catalysts of the fuel cell. The proposed compensation method detects voltage drop caused by those factors, and generates compensation signals for a controller of a DC–DC converter connecting to the output of the fuel cell stack; thus, the voltage drop is reduced by decreasing output current. At the time, insufficient output current to a load is supplied from the batteries. In this paper, voltage drop caused by the abovementioned three factors is analyzed, and the operating principle of the proposed compensation method is specified. To verify this operation and the feasibility of the proposed method, experiments are conducted by applying it to a 10 kW hybrid fuel cell battery system for a forklift. Full article
(This article belongs to the Special Issue Renewable Electric Energy Systems)
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14 pages, 10042 KiB  
Article
An Accurate DDS Method Using Compound Frequency Tuning Word and Its FPGA Implementation
by Yuqing Hou, Changlong Li and Sheng Tang
Electronics 2018, 7(11), 330; https://doi.org/10.3390/electronics7110330 - 16 Nov 2018
Cited by 5 | Viewed by 5890
Abstract
Because of its high resolution, low cost, small volume, low power dissipation and less conversion time consumption, the direct digital synthesizer (DDS) method has been applied more and more in the fields of frequency synthesis and signal generation. However, only a limited number [...] Read more.
Because of its high resolution, low cost, small volume, low power dissipation and less conversion time consumption, the direct digital synthesizer (DDS) method has been applied more and more in the fields of frequency synthesis and signal generation. However, only a limited number of precise frequency signals can be synthesized by the traditional DDS, for the reason that its accumulator modulus is fixed, and its frequency tuning word must be integer. In this paper, a precise DDS method using compound frequency tuning word is proposed, which improves the accuracy of synthesized signals at any frequency points on the premise of guaranteeing the stability of synthesized signals. In order to verify the effectiveness of the new method, a DDS frequency synthesizer based on FPGA is designed and implemented. Taking the rubidium atomic clock PRS10 as standard frequency source, the experiments shows that the frequency stability of the synthesized signal is better than 8.0 × 10−12/s, the relative frequency error is less than 4.8 × 10−12, and that the frequency accuracy is improved by three orders of magnitude compared with the traditional DDS method. Full article
(This article belongs to the Special Issue Signal Processing and Analysis of Electrical Circuit)
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13 pages, 1075 KiB  
Review
Meter Placement in Power System Network—A Comprehensive Review, Analysis and Methodology
by Ramesh Lekshmana, Sanjeevikumar Padmanaban, Sagar Bhaskar Mahajan, Vigna K. Ramachandaramurthy and Jens Bo Holm-Nielsen
Electronics 2018, 7(11), 329; https://doi.org/10.3390/electronics7110329 - 16 Nov 2018
Cited by 5 | Viewed by 4125
Abstract
The blackout in North India due to the failure of the central grid has led to the need for intelligent power system state estimation, where optimal location is necessary to understand. State estimation meter placement plays a major role in the smart operation [...] Read more.
The blackout in North India due to the failure of the central grid has led to the need for intelligent power system state estimation, where optimal location is necessary to understand. State estimation meter placement plays a major role in the smart operation of a modern distributed power system. A literature review of the different algorithms incorporated for the determination of minimal number of meters required for the measurement of real time measurements is presented for the power system and distribution system state estimation, including smart meter location. Full article
(This article belongs to the Special Issue Renewable Electric Energy Systems)
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15 pages, 8394 KiB  
Article
Proposed Scheme of Pliable Gas Insulated Transmission Line and Its Comparative Appraisal Regarding Electrostatic and Dielectric Aspects
by Muhammad Junaid Alvi, Tahir Izhar and Asif Ali Qaiser
Electronics 2018, 7(11), 328; https://doi.org/10.3390/electronics7110328 - 16 Nov 2018
Cited by 6 | Viewed by 4866
Abstract
Gas insulated transmission lines (GILs) are being used in electrical systems regarding power transmission and substation interconnection. However, operational complexities of conventional schemes, such as structural rigidity, corrosion protection, gas leakage in case of seismic vibrations, larger bending radius and jointing complexities which [...] Read more.
Gas insulated transmission lines (GILs) are being used in electrical systems regarding power transmission and substation interconnection. However, operational complexities of conventional schemes, such as structural rigidity, corrosion protection, gas leakage in case of seismic vibrations, larger bending radius and jointing complexities which restrain their application perspectives, could be curtailed by developing a flexible GIL. In this research paper, a new pliable scheme of gas insulated transmission line is proposed. Further, COMSOL Multiphysics® (version 5.1, COMSOL Inc., Stockholm, Sweden) based electrostatic assay and practically performed high voltage tests-based dielectric analysis is performed for the proposed scheme. Electrostatic appraisal is comprised of field utilization based electrostatic stress analysis. In addition, dimensional optimization of pliable GIL regarding enclosure and pitch sizes in relation to electrostatic stresses and field utilization is also performed. Regarding dielectric perusal, experimental setup has been developed for standard lightning impulse and disruptive discharge tests in order to investigate the synergistic dielectric characteristics of proposed flexible post insulators for pliable GIL. Experimental and simulation appraisal unveil that the proposed scheme exhibits almost analogous electrostatic and dielectric behavior in comparison to the conventional GIL scheme and could simplify the operational intricacies associated with conventional scheme. The proposed modifications could eliminate the requirement of trench development, corrosion protection and acceleration dampers, along with a significant reduction in required land area at bends, due to a smaller bending radius which will ultimately result in substantial cost reduction. Full article
(This article belongs to the Special Issue Power Quality in Smart Grids)
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29 pages, 24638 KiB  
Article
A Novel Ten Check Maximum Power Point Tracking Algorithm for a Standalone Solar Photovoltaic System
by Muhammad Mateen Afzal Awan and Tahir Mahmood
Electronics 2018, 7(11), 327; https://doi.org/10.3390/electronics7110327 - 16 Nov 2018
Cited by 25 | Viewed by 4824
Abstract
Optimal energy extraction under partial shading conditions from a photovoltaic (PV) array is particularly challenging. Conventional techniques fail to achieve the global maximum power point (GMPP) under such conditions, while soft computing techniques have provided better results. The main contribution of this paper [...] Read more.
Optimal energy extraction under partial shading conditions from a photovoltaic (PV) array is particularly challenging. Conventional techniques fail to achieve the global maximum power point (GMPP) under such conditions, while soft computing techniques have provided better results. The main contribution of this paper is to devise an algorithm to track the GMPP accurately and efficiently. For this purpose, a ten check (TC) algorithm was proposed. The effectiveness of this algorithm was tested with different shading patterns. Results were compared with the top conventional algorithm perturb and observe (P&O) and the best soft computing technique flower pollination algorithm (FPA). It was found that the proposed algorithm outperformed them. Analysis demonstrated that the devised algorithm achieved the GMPP efficiently and accurately as compared to the P&O and the FPA algorithms. Simulations were performed in MATLAB/Simulink. Full article
(This article belongs to the Special Issue Renewable Electric Energy Systems)
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20 pages, 6266 KiB  
Article
A Nonlinearly Modulated Logistic Map with Delay for Image Encryption
by Shouliang Li, Benshun Yin, Weikang Ding, Tongfeng Zhang and Yide Ma
Electronics 2018, 7(11), 326; https://doi.org/10.3390/electronics7110326 - 15 Nov 2018
Cited by 11 | Viewed by 3322
Abstract
Considering that a majority of the traditional one-dimensional discrete chaotic maps have disadvantages including a relatively narrow chaotic range, smaller Lyapunov exponents, and excessive periodic windows, a new nonlinearly modulated Logistic map with delay model (NMLD) is proposed. Accordingly, a chaotic map called [...] Read more.
Considering that a majority of the traditional one-dimensional discrete chaotic maps have disadvantages including a relatively narrow chaotic range, smaller Lyapunov exponents, and excessive periodic windows, a new nonlinearly modulated Logistic map with delay model (NMLD) is proposed. Accordingly, a chaotic map called a first-order Feigenbaum-Logistic NMLD (FL-NMLD) is proposed. Simulation results demonstrate that FL-NMLD has a considerably wider chaotic range, larger Lyapunov exponents, and superior ergodicity compared with existing chaotic maps. Based on FL-NMLD, we propose a new image encryption algorithm that joins the pixel plane and bit-plane shuffle (JPB). The simulation and test results confirm that JPB has higher security than simple pixel-plane encryption and is faster than simple bit-plane encryption. Moreover, it can resist the majority of attacks including statistical and differential attacks. Full article
(This article belongs to the Special Issue Recent Developments on Time-Delay Systems and Its Applications)
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21 pages, 1147 KiB  
Article
Module Based Floorplanning Methodology to Satisfy Voltage Island and Fixed Outline Constraints
by Srinath Balasubramanian, Arunapriya Panchanathan, Bharatiraja Chokkalingam, Sanjeevikumar Padmanaban and Zbigniew Leonowicz
Electronics 2018, 7(11), 325; https://doi.org/10.3390/electronics7110325 - 15 Nov 2018
Cited by 16 | Viewed by 3963
Abstract
Multiple supply voltage is the most prevalent method for low power reduction in the design of modern Integrated circuits. Floorplanning process in this design performs positioning of functional blocks in the layout satisfying both fixed outline and voltage island constraints. The floorplans while [...] Read more.
Multiple supply voltage is the most prevalent method for low power reduction in the design of modern Integrated circuits. Floorplanning process in this design performs positioning of functional blocks in the layout satisfying both fixed outline and voltage island constraints. The floorplans while satisfying these two significant constraints causes significant rise in wirelength and congestion. In this paper, a congestion and wirelength aware floorplanning algorithm is proposed which allows effective placement of functional blocks in the layout to satisfying fixed outline and voltage island constraints simultaneously. To perform voltage island floorplanning, the proposed algorithm uses Skewed binary tree representation scheme to operate the functional blocks in its predefined voltage level. The proposed methodology determines the feasible dimensions of the functional blocks in the representation which aids the placement process for the reduction of congestion and wirelength. With these optimal dimensions of the functional blocks, floorplanning is also performed for the layouts of aspect 1:1, 2:1, and 3:1, to evaluate the ability of proposed algorithm for satisfying the fixed outline constraint. The proposed methodology is implemented in the layout of InternationalWorkshop on Logic and Synthesis (IWLS) benchmarks circuits for experimental purpose. The resulting floorplans were iteratively optimized for optimal reduction of wirelength and congestion. Experimental results show that the proposed methodology outperforms existing state-of-the-art approaches in wirelength reduction by about 18.65% and in congestion reduction by around 63%, while delivering the 30.35% power consumption. Full article
(This article belongs to the Special Issue Hardware and Architecture)
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16 pages, 1120 KiB  
Article
Equivalent Circuit Model for Cu(In,Ga)Se2 Solar Cells Operating at Different Temperatures and Irradiance
by Matteo Bronzoni, Lorenzo Colace, Andrea De Iacovo, Antonino Laudani, Gabriele Maria Lozito, Valentina Lucaferri, Martina Radicioni and Stefano Rampino
Electronics 2018, 7(11), 324; https://doi.org/10.3390/electronics7110324 - 15 Nov 2018
Cited by 11 | Viewed by 3822
Abstract
The modeling of photovoltaic cells is an essential step in the analysis of the performances and characterization of PV systems. This paper proposes an experimental study of the dependence of the five parameters of the one-diode model on atmospheric conditions, i.e., irradiance and [...] Read more.
The modeling of photovoltaic cells is an essential step in the analysis of the performances and characterization of PV systems. This paper proposes an experimental study of the dependence of the five parameters of the one-diode model on atmospheric conditions, i.e., irradiance and temperature in the case of thin-film solar cells. The extraction of the five parameters was performed starting from two sets of experimental data obtained from Cu(In,Ga)Se2 solar cells fabricated by the low-temperature pulsed electron deposition technique. A reduced form approach of the one-diode model has been adopted, leading to an accurate identification of the cell. It was possible to elaborate suitable relations describing the behavior of the parameters as functions of the environmental conditions. This allowed accurately predicting the trends of the parameters from a pair of curves, instead of a whole set of measurements. The developed model describing the dependence on irradiance and temperature was validated by means of a large set of experimental measurements on several Cu(In,Ga)Se2 (CIGS) devices built with the same technological process. Full article
(This article belongs to the Section Microelectronics)
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16 pages, 1139 KiB  
Review
Failure Modes, Mechanisms, Effects, and Criticality Analysis of Ceramic Anodes of Solid Oxide Fuel Cells
by Nripendra K. Patel, Sean R. Bishop, Robert G. Utter, Diganta Das and Michael Pecht
Electronics 2018, 7(11), 323; https://doi.org/10.3390/electronics7110323 - 15 Nov 2018
Cited by 5 | Viewed by 6335
Abstract
Solid oxide fuel cells (SOFCs) are a highly efficient chemical to electrical energy conversion devices that have potential in a global energy strategy. The wide adoption of SOFCs is currently limited by cost and concerns about cell durability. Improved understanding of their degradation [...] Read more.
Solid oxide fuel cells (SOFCs) are a highly efficient chemical to electrical energy conversion devices that have potential in a global energy strategy. The wide adoption of SOFCs is currently limited by cost and concerns about cell durability. Improved understanding of their degradation modes and mechanisms combined with reduction–oxidation stable anodes via all-ceramic-anode cell technology are expected to lead to durability improvements, while economies of scale for production will mitigate cost of commercialization. This paper presents an Ishikawa analysis and a failure modes, mechanisms, effects, and criticality analysis (FMMECA) for all-ceramic anode based SOFCs. FMMECA takes into account the life cycle conditions, multiple failure mechanisms, and their potential effects on fuel-cell health and safety. Full article
(This article belongs to the Special Issue Renewable Electric Energy Systems)
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10 pages, 1001 KiB  
Article
Protecting Image Processing Pipelines against Configuration Memory Errors in SRAM-Based FPGAs
by Luis Alberto Aranda, Pedro Reviriego and Juan Antonio Maestro
Electronics 2018, 7(11), 322; https://doi.org/10.3390/electronics7110322 - 15 Nov 2018
Cited by 3 | Viewed by 3890
Abstract
Image processing systems are widely used in space applications, so different radiation-induced malfunctions may occur in the system depending on the device that is implementing the algorithm. SRAM-based FPGAs are commonly used to speed up the image processing algorithm, but then the system [...] Read more.
Image processing systems are widely used in space applications, so different radiation-induced malfunctions may occur in the system depending on the device that is implementing the algorithm. SRAM-based FPGAs are commonly used to speed up the image processing algorithm, but then the system could be vulnerable to configuration memory errors caused by single event upsets (SEUs). In those systems, the captured image is streamed pixel by pixel from the camera to the FPGA. Certain local operations such as median or rank filters need to process the image locally instead of pixel by pixel, so some particular pixel caching structures such as line-buffer-based pipelines can be used to accelerate the filtering process. However, an SRAM-based FPGA implementation of these pipelines may have malfunctions due to the mentioned configuration memory errors, so an error mitigation technique is required. In this paper, a novel method to protect line-buffer-based pipelines against SRAM-based FPGA configuration memory errors is presented. Experimental results show that, using our protection technique, considerable savings in terms of FPGA resources can be achieved while maintaining the SEU protection coverage provided by other classic pipeline protection schemes. Full article
(This article belongs to the Special Issue Radiation Tolerant Electronics)
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17 pages, 4367 KiB  
Article
An All-Region State-of-Charge Estimator Based on Global Particle Swarm Optimization and Improved Extended Kalman Filter for Lithium-Ion Batteries
by Xin Lai, Wei Yi, Yuejiu Zheng and Long Zhou
Electronics 2018, 7(11), 321; https://doi.org/10.3390/electronics7110321 - 14 Nov 2018
Cited by 22 | Viewed by 4468
Abstract
In this paper, a novel model parameter identification method and a state-of-charge (SOC) estimator for lithium-ion batteries (LIBs) are proposed to improve the global accuracy of SOC estimation in the all SOC range (0–100%). Firstly, a subregion optimization method based on particle swarm [...] Read more.
In this paper, a novel model parameter identification method and a state-of-charge (SOC) estimator for lithium-ion batteries (LIBs) are proposed to improve the global accuracy of SOC estimation in the all SOC range (0–100%). Firstly, a subregion optimization method based on particle swarm optimization is developed to find the optimal model parameters of LIBs in each subregion, and the optimal number of subregions is investigated from the perspective of accuracy and computation time. Then, to solve the problem of a low accuracy of SOC estimation caused by large model error in the low SOC range, an improved extended Kalman filter (IEKF) algorithm with variable noise covariance is proposed. Finally, the effectiveness of the proposed methods are verified by experiments on two kinds of batteries under three working cycles, and case studies show that the proposed IEKF has better accuracy and robustness than the traditional extended Kalman filter (EKF) in the all SOC range. Full article
(This article belongs to the Special Issue Applications of Power Electronics)
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24 pages, 3929 KiB  
Article
Hardware Considerations for Tensor Implementation and Analysis Using the Field Programmable Gate Array
by Ian Grout and Lenore Mullin
Electronics 2018, 7(11), 320; https://doi.org/10.3390/electronics7110320 - 13 Nov 2018
Cited by 8 | Viewed by 4852
Abstract
In today’s complex embedded systems targeting internet of things (IoT) applications, there is a greater need for embedded digital signal processing algorithms that can effectively and efficiently process complex data sets. A typical application considered is for use in supervised and unsupervised machine [...] Read more.
In today’s complex embedded systems targeting internet of things (IoT) applications, there is a greater need for embedded digital signal processing algorithms that can effectively and efficiently process complex data sets. A typical application considered is for use in supervised and unsupervised machine learning systems. With the move towards lower power, portable, and embedded hardware-software platforms that meet the current and future needs for such applications, there is a requirement on the design and development communities to consider different approaches to design realization and implementation. Typical approaches are based on software programmed processors that run the required algorithms on a software operating system. Whilst such approaches are well supported, they can lead to solutions that are not necessarily optimized for a particular problem. A consideration of different approaches to realize a working system is therefore required, and hardware based designs rather than software based designs can provide performance benefits in terms of power consumption and processing speed. In this paper, consideration is given to utilizing the field programmable gate array (FPGA) to implement a combined inner and outer product algorithm in hardware that utilizes the available hardware resources within the FPGA. These products form the basis of tensor analysis operations that underlie the data processing algorithms in many machine learning systems. Full article
(This article belongs to the Special Issue Signal Processing and Analysis of Electrical Circuit)
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20 pages, 12656 KiB  
Article
A Novel Synchronization Technique for Wireless Power Transfer Systems
by Xin Liu, Nan Jin, Xijun Yang, Tianfeng Wang, Khurram Hashmi and Houjun Tang
Electronics 2018, 7(11), 319; https://doi.org/10.3390/electronics7110319 - 13 Nov 2018
Cited by 10 | Viewed by 5848
Abstract
Recently, wireless power transfer (WPT) systems with active receivers have been proposed for conduction loss reduction, bidirectional power transfer and efficiency improvement. However, the synchronization of WPT systems is complex in nature with the selection of high operating frequencies. Without proper synchronization, power [...] Read more.
Recently, wireless power transfer (WPT) systems with active receivers have been proposed for conduction loss reduction, bidirectional power transfer and efficiency improvement. However, the synchronization of WPT systems is complex in nature with the selection of high operating frequencies. Without proper synchronization, power oscillations appear and the system can become unstable. In this paper, a detailed analysis of different WPT systems is presented and the essence of the synchronization technique is derived as being composed of two functions: independent frequency locking and reference phase calibration. The voltage across the receiver-side compensation capacitor is divided and utilized for frequency locking, whereas the reference phase calibration is realized through software code. The proposed method is effective and easy to implement, with a lower overall cost due to its simplicity. The technique can work effectively at high frequency and withstand large variations of operating frequency, load and mutual inductance. In addition, it can address the synchronization problem of multiple active receiver WPT systems with and without cross coupling among the receiving coils. Theoretical analysis and experimental results validate the proposed technique. Full article
(This article belongs to the Special Issue Applications of Power Electronics)
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21 pages, 9742 KiB  
Article
EMI Filter Design for a Single-stage Bidirectional and Isolated AC–DC Matrix Converter
by Diogo Varajão, Rui Esteves Araújo, Luís M. Miranda and João A. Peças Lopes
Electronics 2018, 7(11), 318; https://doi.org/10.3390/electronics7110318 - 12 Nov 2018
Cited by 20 | Viewed by 12189
Abstract
This paper describes the design of an electromagnetic interference (EMI) filter for the high-frequency link matrix converter (HFLMC). The proposed method aims to systematize the design process for pre-compliance with CISPR 11 Class B standard in the frequency range 150 kHz to 30 [...] Read more.
This paper describes the design of an electromagnetic interference (EMI) filter for the high-frequency link matrix converter (HFLMC). The proposed method aims to systematize the design process for pre-compliance with CISPR 11 Class B standard in the frequency range 150 kHz to 30 MHz. This approach can be extended to other current source converters which allows time-savings during the project of the filter. Conducted emissions are estimated through extended simulation and take into account the effect of the measurement apparatus. Differential-mode (DM) and common-mode (CM) filtering stages are projected separately and then integrated in a synergistic way in a single PCB to reduce volume and weight. A prototype of the filter was constructed and tested in the laboratory. Experimental results with the characterization of the insertion losses following the CISPR 17 standard are provided. The attenuation capability of the filter was demonstrated in the final part of the paper. Full article
(This article belongs to the Special Issue Applications of Power Electronics)
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15 pages, 495 KiB  
Article
Downlink Spectral Efficiency Analysis in Distributed Massive MIMO with Phase Noise
by Qian Lv, Jiamin Li, Pengcheng Zhu, Dongming Wang and Xiaohu You
Electronics 2018, 7(11), 317; https://doi.org/10.3390/electronics7110317 - 12 Nov 2018
Cited by 4 | Viewed by 3727
Abstract
To achieve the advantages provided by massive multiple-input multiple-output (MIMO), a large number of antennas need to be deployed at the base station. However, for the reason of cost, inexpensive hardwares are employed in the realistic scenario, which makes the system distorted by [...] Read more.
To achieve the advantages provided by massive multiple-input multiple-output (MIMO), a large number of antennas need to be deployed at the base station. However, for the reason of cost, inexpensive hardwares are employed in the realistic scenario, which makes the system distorted by hardware impairments. Hence, in this paper, we analyze the downlink spectral efficiency in distributed massive MIMO with phase noise and amplified thermal noise. We provide an effective channel model considering large-scale fading, small-scale fast fading and phase noise. Based on the model, the estimated channel state information (CSI) is obtained during the pilot phase. Under the imperfect CSI, the closed-form expressions of downlink achievable rates with maximum ratio transmission (MRT) and zero-forcing (ZF) precoders in distributed massive MIMO are derived. Furthermore, we also give the user ultimate achievable rates when the number of antennas tends to infinity with both precoders. Based on these expressions, we analyze the impacts of phase noise on the spectral efficiency. It can be concluded that the same limit rate is achieved with both precoders when phase noise is present, and phase noise limits the spectral efficiency. Numerical results show that ZF outdoes MRT precoder in spectral efficiency and ZF precoder is more affected by phase noise. Full article
(This article belongs to the Special Issue Massive MIMO Systems)
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25 pages, 6660 KiB  
Article
SINDVis: User-Centered Dynamic Interactive Visualization System for Space Information Networks
by Shaobo Yu, Lingda Wu, Xitao Zhang, Xiangli Meng and Pengrui Cen
Electronics 2018, 7(11), 316; https://doi.org/10.3390/electronics7110316 - 12 Nov 2018
Cited by 1 | Viewed by 2961
Abstract
As an important national strategy infrastructure, the Space Information Network (SIN) is a powerful platform for future information support. In this paper, we design and implement a user-centered, dynamic, interactive visualization system (SINDVis), and aim to assist multi-class users to understand, build, develop, [...] Read more.
As an important national strategy infrastructure, the Space Information Network (SIN) is a powerful platform for future information support. In this paper, we design and implement a user-centered, dynamic, interactive visualization system (SINDVis), and aim to assist multi-class users to understand, build, develop, maintain, and manage the SIN. We introduce the concept and architecture of SIN, summarize the key technologies of dynamic visualization and visual analysis, and analyze the basic characteristics of three types of users. Combining the content above, we design the architecture of SINDVis from an input module, a core-processing module, an output module, and a user body. We also describe eight basic functions of the entity domain view (GeoView) and topology domain view (TopolView). Meanwhile, we analyze the implementation methods of the GeoView and TopolView, including an improved Force-Directed Algorithm (FDA) layout, Fusion of Animation and Timeline (FAT) visualization, and Panning and Zooming (P&Z) interactions. We analyze the experiment platforms and running environments of the GeoView and TopolView and realize the main contents of both views with a typical SIN. The results also verify the validity and feasibility of the theories and methods proposed. Finally, we discuss and analyze experimental results and the advantages and disadvantages of the SINDVis and look forward to future work. With the development of visualization and visual analysis technology, both application-driven and user-interaction features are gradually highlighted. We introduce the visualization technology into the field of SIN in order to provide new ideas for the basic theory and key technology research of SIN. Full article
(This article belongs to the Section Computer Science & Engineering)
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10 pages, 251 KiB  
Article
Competition in Service Provision between Slice Operators in 5G Networks
by Luis Guijarro, Jose R. Vidal and Vicent Pla
Electronics 2018, 7(11), 315; https://doi.org/10.3390/electronics7110315 - 12 Nov 2018
Cited by 10 | Viewed by 3287
Abstract
Network slicing is gaining an increasing importance as an effective way to introduce flexibility in the management of resources in 5G networks. We envision a scenario where a set of network operators outsource their respective networks to one Infrastructure Provider (InP), and use [...] Read more.
Network slicing is gaining an increasing importance as an effective way to introduce flexibility in the management of resources in 5G networks. We envision a scenario where a set of network operators outsource their respective networks to one Infrastructure Provider (InP), and use network slicing mechanisms to request the resources as needed for service provision. The InP is then responsible for the network operation and maintenance, while the network operators become Virtual Network Operators (VNOs). We model a setting where two VNOs compete for the users in terms of quality of service, by strategically distributing its share of the aggregated cells capacity managed by the InP among its subscribers. The results show that the rate is allocated among the subscribers at each cell in a way that mimics the overall share that each VNO is entitled to, and that this allocation is the Nash equilibrium of the strategic slicing game between the VNOs. We conclude that network sharing and slicing provide an attractive flexibility in the allocation of resources without the need to enforce a policy through the InP. Full article
(This article belongs to the Special Issue IoT in 5G)
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14 pages, 4747 KiB  
Article
Turbojet Engine Industrial Min–Max Controller Performance Improvement Using Fuzzy Norms
by Soheil Jafari and Theoklis Nikolaidis
Electronics 2018, 7(11), 314; https://doi.org/10.3390/electronics7110314 - 11 Nov 2018
Cited by 14 | Viewed by 5081
Abstract
The Min–Max control strategy is the most widely used control algorithm for gas turbine engines. This strategy uses minimum and maximum mathematical functions to select the winner of different transient engine control loops at any instantaneous time. This paper examines the potential of [...] Read more.
The Min–Max control strategy is the most widely used control algorithm for gas turbine engines. This strategy uses minimum and maximum mathematical functions to select the winner of different transient engine control loops at any instantaneous time. This paper examines the potential of using fuzzy T and S norms in Min–Max selection strategy to improve the performance of the controller and the gas turbine engine dynamic behavior. For this purpose, different union and intersection fuzzy norms are used in control strategy instead of using minimum and maximum functions to investigate the impact of this idea in gas turbine engines controller design and optimization. A turbojet engine with an industrial Min–Max control strategy including steady-state and transient control loops is selected as the case study. Different T and S norms including standard, bounded, Einstein, algebraic, and Hamacher norms are considered to be used in control strategy to select the best transient control loop for the engine. Performance indices are defined as pilot command tracking as well as the engine response time. The simulation results confirm that using Einstein and Hamacher norms in the Min–Max selection strategy could enhance the tracking capability and the response time to the pilot command respectively. The limitations of the proposed method are also discussed and potential solutions for dealing with these challenges are proposed. The methodological approach presented in this research could be considered for enhancement of control systems in different types of gas turbine engines from practical point of view. Full article
(This article belongs to the Section Systems & Control Engineering)
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14 pages, 5009 KiB  
Article
A New CUK-Based Z-Source Inverter
by Baocheng Wang and Wei Tang
Electronics 2018, 7(11), 313; https://doi.org/10.3390/electronics7110313 - 10 Nov 2018
Cited by 13 | Viewed by 3766
Abstract
This paper proposes a new three-switch single-phase Z-source inverter (ZSI) based on a CUK converter, which is named a CUK-based ZSI. This topology has characteristics of buck‒boost capability and dual grounding. In addition, the voltage gain of proposed inverter is higher than those [...] Read more.
This paper proposes a new three-switch single-phase Z-source inverter (ZSI) based on a CUK converter, which is named a CUK-based ZSI. This topology has characteristics of buck‒boost capability and dual grounding. In addition, the voltage gain of proposed inverter is higher than those of the single-phase quasi-Z-source and semi-Z-source inverters. Aside from that, a simple control method is presented to achieve the linear voltage gain. The operational principle of the proposed topology is described. Finally, a performance evaluation is carried out and the test results verify the effectiveness of the proposed solution. Full article
(This article belongs to the Section Microelectronics)
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19 pages, 2642 KiB  
Article
Evaluation by Neutron Radiation of the NMR-MPar Fault-Tolerance Approach Applied to Applications Running on a 28-nm Many-Core Processor
by Vanessa Vargas, Pablo Ramos and Raoul Velazco
Electronics 2018, 7(11), 312; https://doi.org/10.3390/electronics7110312 - 8 Nov 2018
Cited by 3 | Viewed by 3427
Abstract
Currently, there is a special interest in validating the use of Commercial-Off-The-Shelf (COTS) multi/many-core processors for critical applications thanks to their high performance, low power consumption and affordability. However, the continuous shrinking of transistor geometry and the increasing complexity of these devices dramatically [...] Read more.
Currently, there is a special interest in validating the use of Commercial-Off-The-Shelf (COTS) multi/many-core processors for critical applications thanks to their high performance, low power consumption and affordability. However, the continuous shrinking of transistor geometry and the increasing complexity of these devices dramatically affect their sensitivity to natural radiation, and thus diminish their reliability. One of the most common effects produced by natural radiation is the Single Event Upset which is the bit-flip of a memory content producing unexpected results at application-level. For this reason, manufacturers and users implement hardware and software error-mitigation techniques on multi/many-core processors. In this context, the present work aims at evaluating a new fault-tolerance approach based on N-Modular redundancy (NMR) and partitioning called NMR-MPar by means of 14 MeV neutron radiation ground testing in order to emulate the effects of high-energy neutrons present at avionics altitudes. For evaluation purposes, a case-study is implemented on the 28 nm CMOS KALRAY MPPA-256 many-core processor running two complementary benchmarks applications: a distributed Matrix Multiplication and the Travel Salesman Problem. Radiation experiments were conducted in GENEPI2 particle-accelerator. The correctness of the results of the application when an error is detected confirms the approach’s effectiveness and boosts their usage on avionics applications. Full article
(This article belongs to the Section Computer Science & Engineering)
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