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Electronics, Volume 8, Issue 9 (September 2019) – 147 articles

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Cover Story (view full-size image) Power Converter Array, at the edge of power electronics Design Automation for Manufacturing. [...] Read more.
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Open AccessFeature PaperArticle
An Approval of MPPT Based on PV Cell’s Simplified Equivalent Circuit During Fast-Shading Conditions
Electronics 2019, 8(9), 1060; https://doi.org/10.3390/electronics8091060 - 19 Sep 2019
Cited by 4 | Viewed by 1209
Abstract
The partial shading conditions significantly affect the functionality of solar power plants despite the presence of multiple maximum power point tracking systems. The primary cause of this problem is the presence of local maxima in the power–current and/or power–voltage characteristic curves that restrict [...] Read more.
The partial shading conditions significantly affect the functionality of solar power plants despite the presence of multiple maximum power point tracking systems. The primary cause of this problem is the presence of local maxima in the power–current and/or power–voltage characteristic curves that restrict the functionality of the conventional maximum power point tracking systems. The present article proposes a modified algorithm based on the simplified equivalent circuit of solar cells to improve the functionality of traditional maximum power point tracking systems. This algorithm provides a method for regularly monitoring the photo-current of each solar module. The upper and lower boundaries of the regulating parameter such as current or voltage are decided very precisely, which is helpful to find the location of the global maximum. During a sequential search, the control system accurately determines the lower and upper boundaries of the global maximum. Simultaneously, the maximum power point tracking system increases the photovoltaic current up to one of these boundaries and applies one of the conventional algorithms. Additionally, the control system regularly monitors the photovoltaic characteristics and changes the limits of regulating parameter concerning any change in global maximum location. This proposed method is fast and precise to locate the global maximum boundaries and to track global maximum even under fast-changing partial shading conditions. The improved performance and overall efficiency are validated by simulation study for variable solar irradiance. Full article
(This article belongs to the Section Power Electronics)
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Open AccessFeature PaperArticle
Reliability Evaluation of PV Systems with Integrated Battery Energy Storage Systems: DC-Coupled and AC-Coupled Configurations
Electronics 2019, 8(9), 1059; https://doi.org/10.3390/electronics8091059 - 19 Sep 2019
Cited by 11 | Viewed by 1339
Abstract
Deployment of a battery energy storage system for the photovoltaic (PV) application has been increasing at a fast rate. Depending on the number of power conversion units and their type of connection, the PV-battery system can be classified into DC- and AC-coupled configurations. [...] Read more.
Deployment of a battery energy storage system for the photovoltaic (PV) application has been increasing at a fast rate. Depending on the number of power conversion units and their type of connection, the PV-battery system can be classified into DC- and AC-coupled configurations. The number of the components and their electrical loading directly affects the reliability of each of the configurations. Hence, in order to assure high efficiency and lifetime of the PV-battery system, reliability assessment of power conversion units (representing the most reliability-critical system components) is necessary. With respect to that, in this paper, a reliability assessment of the PV-battery system is performed and a comparison of the DC- and AC-coupled configuration reliability is conducted. In the analysis, all parts of the power conversion system, i.e., DC/DC and DC/AC converter units, are taken into consideration and component-, converter- and system-level reliability is assessed. A case study of 6 kW PV system with integrated 3 kW/7.5 kWh battery system has shown that higher reliability is achieved for DC-coupled configuration. The obtained results indicate that the probability of failure for the 15% of the population for DC-coupled configuration occurs 7 years later than that is a case for AC-coupled configuration. Finally, the presented analysis can serve as a benchmark for lifetime and reliability assessment of power conversion units in PV-battery systems for both configuration types. It provides information about differences in electrical and thermal loading of the power conversion units and resulting reliability of the two configurations. Full article
(This article belongs to the Special Issue Challenges and New Trends in Power Electronic Devices Reliability)
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Open AccessArticle
A Novel Left-Turn Signal Control Method for Improving Intersection Capacity in a Connected Vehicle Environment
Electronics 2019, 8(9), 1058; https://doi.org/10.3390/electronics8091058 - 19 Sep 2019
Cited by 3 | Viewed by 649
Abstract
Setting up an exclusive left-turn lane and corresponding signal phase for intersection traffic safety and efficiency will decrease the capacity of the intersection when there are less or no left-turn movements. This is especially true during rush hours because of the ineffective use [...] Read more.
Setting up an exclusive left-turn lane and corresponding signal phase for intersection traffic safety and efficiency will decrease the capacity of the intersection when there are less or no left-turn movements. This is especially true during rush hours because of the ineffective use of left-turn lane space and signal phase duration. With the advantages of vehicle-to-infrastructure (V2I) communication, a novel intersection signal control model is proposed which sets up variable lane direction arrow marking and turns the left-turn lane into a controllable shared lane for left-turn and through movements. The new intersection signal control model and its control strategy are presented and simulated using field data. After comparison with two other intersection control models and control strategies, the new model is validated to improve the intersection capacity in rush hours. Besides, variable lane lines and the corresponding control method are designed and combined with the left-turn waiting area to overcome the shortcomings of the proposed intersection signal control model and control strategy. Full article
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Open AccessFeature PaperArticle
Model-Checking Speculation-Dependent Security Properties: Abstracting and Reducing Processor Models for Sound and Complete Verification
Electronics 2019, 8(9), 1057; https://doi.org/10.3390/electronics8091057 - 19 Sep 2019
Viewed by 638
Abstract
Spectre and Meltdown attacks in modern microprocessors represent a new class of attacks that have been difficult to deal with. They underline vulnerabilities in hardware design that have been going unnoticed for years. This shows the weakness of the state-of-the-art verification process and [...] Read more.
Spectre and Meltdown attacks in modern microprocessors represent a new class of attacks that have been difficult to deal with. They underline vulnerabilities in hardware design that have been going unnoticed for years. This shows the weakness of the state-of-the-art verification process and design practices. These attacks are OS-independent, and they do not exploit any software vulnerabilities. Moreover, they violate all security assumptions ensured by standard security procedures, (e.g., address space isolation), and, as a result, every security mechanism built upon these guarantees. These vulnerabilities allow the attacker to retrieve leaked data without accessing the secret directly. Indeed, they make use of covert channels, which are mechanisms of hidden communication that convey sensitive information without any visible information flow between the malicious party and the victim. The root cause of this type of side-channel attacks lies within the speculative and out-of-order execution of modern high-performance microarchitectures. Since modern processors are hard to verify with standard formal verification techniques, we present a methodology that shows how to transform a realistic model of a speculative and out-of-order processor into an abstract one. Following related formal verification approaches, we simplify the model under consideration by abstraction and refinement steps. We also present an approach to formally verify the abstract model using a standard model checker. The theoretical flow, reliant on established formal verification results, is introduced and a sketch of proof is provided for soundness and correctness. Finally, we demonstrate the feasibility of our approach, by applying it on a pipelined DLX RISC-inspired processor architecture. We show preliminary experimental results to support our claim, performing Bounded Model-Checking with a state-of-the-art model checker. Full article
(This article belongs to the Special Issue State-of-the-Art of Cyber Security)
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Open AccessArticle
Atomic Norm-Based DOA Estimation with Dual-Polarized Radar
Electronics 2019, 8(9), 1056; https://doi.org/10.3390/electronics8091056 - 19 Sep 2019
Cited by 3 | Viewed by 742
Abstract
In the dual-polarized radar system, the horizontally and vertically polarized signals can be exploited to improve the direction of arrival (DOA) estimation performance. In this paper, the DOA estimation problem is considered in the dual-polarized radar. By exploiting the target sparsity in the [...] Read more.
In the dual-polarized radar system, the horizontally and vertically polarized signals can be exploited to improve the direction of arrival (DOA) estimation performance. In this paper, the DOA estimation problem is considered in the dual-polarized radar. By exploiting the target sparsity in the spatial domain, the sparse-based method is proposed after formulating the DOA estimation problem as a sparse reconstruction problem. In the traditionally sparse methods using the compressed sensing (CS) theory, the spatial domain is discretized into grids to establish a dictionary matrix and solve the sparse reconstruction problem, but the off-grid error is introduced in the discretized grids. Therefore, we formulate a novel definition of atomic norm for the dual-polarized signals and give an atomic norm-based method to denoise the received signals. Then, an efficient semidefinite program (SDP) is derived, and the DOA is estimated by searching the peak values of the denoised signals. Simulation results show that the proposed method can significantly improve the DOA estimation performance in the dual-polarized radar. Additionally, compared with the state-of-art methods, the proposed method has better estimation performance with relatively low computational complexity. Full article
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Open AccessArticle
Testing and Validation of Adaptive Impedance Matching System for Broadband Antenna
Electronics 2019, 8(9), 1055; https://doi.org/10.3390/electronics8091055 - 19 Sep 2019
Cited by 1 | Viewed by 602
Abstract
Broad RF impedance matching is challenging; however, the need for broadband matching is found frequently in modern RF and wireless systems with multiple wireless standards. Moreover, in 5G technology, multiple frequency bands are used, and these systems typically employ a broadband antenna or [...] Read more.
Broad RF impedance matching is challenging; however, the need for broadband matching is found frequently in modern RF and wireless systems with multiple wireless standards. Moreover, in 5G technology, multiple frequency bands are used, and these systems typically employ a broadband antenna or multiple antennas. Antenna impedances vary from design targets for many reasons including manufacturing process variations or antenna environment changes. An adaptive impedance matching system (AIMS) for testing and validation is introduced, and its implementation is shown in this paper. The AIMS can control impedance matching tuner settings to provide an arbitrary impedance frequency-varying load that meets user-defined conditions. This AIMS provides a testing and validation system for broadband antennas that can be characterized by various settings of the impedance matching tuner. As a device under test (DUT), a three-stub reconfigurable filter was used as the impedance matching tuner on a RT/Duroid 6010 RF board. It was integrated with a control circuit board. This AIMS implementation also included an antenna impedance tuner that can vary the distance between the antenna and the ground plane. This model represents practical antenna impedance variations. The AIMS controls a network analyzer and the impendence matching tuner. The adaptive control program on a PC was developed to perform an effective two-pass tuning strategy. This article presents the successful automated tuned results and their numerical evaluations of three cases that were generated by the antenna impedance tuner. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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Open AccessArticle
Impact of IT Devices Production Quality on the Level of Protection of Processed Information against the Electromagnetic Infiltration Process
Electronics 2019, 8(9), 1054; https://doi.org/10.3390/electronics8091054 - 19 Sep 2019
Cited by 2 | Viewed by 663
Abstract
Due to the variety and multiplicity of electronic devices, the issue of electromagnetic environment protection is becoming more and more important. We often hear about how necessary it is for electronic devices to meet appropriate requirements. Meeting these requirements determines whether a device [...] Read more.
Due to the variety and multiplicity of electronic devices, the issue of electromagnetic environment protection is becoming more and more important. We often hear about how necessary it is for electronic devices to meet appropriate requirements. Meeting these requirements determines whether a device can be marketed. Unfortunately, the electrical parameters of electronic components have a very wide range of tolerances. For this reason, measured values of electromagnetic disturbances generated by devices of the same type are not always identical. Differences between those values may reach up to several dB. This problem also concerns electromagnetic emissions correlated with the processed information, which are very sensitive to electromagnetic infiltration process. Issues related to the problem of protection of electromagnetic environment are shown on the basis of research results obtained for several devices of the same type. Mentioned level differences of electromagnetic emissions can decide about a classification of device from viewpoint of protection of information against electromagnetic penetration process. These differences may be a treat to information security. Higher levels of valuable emissions force an application of additional methods limiting an effectiveness of electromagnetic penetration process. This particularly applies to IT devices with a wide range of applications, e.g., laptops and desktop computers. In this paper, this phenomenon was presented on the basis of tests of several devices of the same type. Also, there were carried out analyses of influence of increase levels of valuable emissions on a security zone radius. Full article
(This article belongs to the Special Issue Applications of Electromagnetic Waves) Printed Edition available
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Open AccessArticle
A Systematic Equalizer Design Technique Using Backward Directional Design
Electronics 2019, 8(9), 1053; https://doi.org/10.3390/electronics8091053 - 18 Sep 2019
Viewed by 600
Abstract
This paper presents a systematic equalizer design methodology using a backward directional design (BDD). The proposed design method includes pre-emphasis and crosstalk cancellation design and offers a proper waveform solution for transmitters (TX). Since it is driven by a user-defined specification, it avoids [...] Read more.
This paper presents a systematic equalizer design methodology using a backward directional design (BDD). The proposed design method includes pre-emphasis and crosstalk cancellation design and offers a proper waveform solution for transmitters (TX). Since it is driven by a user-defined specification, it avoids over/under design, reducing wasted power. Furthermore, the proposed design procedure is summarized in systematic algorithms and provides an automated design environment. The procedure has been tested for various line conditions to verify the algorithms. The result shows that the proposed method successfully designs equalizers to within a 2.4% error. Full article
(This article belongs to the Special Issue Energy Efficient Circuit Design Techniques for Low Power Systems)
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Open AccessArticle
Feedforward Interpolation Error Compensation Method for Field Weakening Operation Region of PMSM Drive
Electronics 2019, 8(9), 1052; https://doi.org/10.3390/electronics8091052 - 18 Sep 2019
Cited by 1 | Viewed by 739
Abstract
This study proposes a field weakening control method with interpolation error compensation of the look-up table based permanent-magnet synchronous machine (PMSM) method. The look-up table (LUT) based control method has robust control characteristics compared to other control methods that use linear controllers for [...] Read more.
This study proposes a field weakening control method with interpolation error compensation of the look-up table based permanent-magnet synchronous machine (PMSM) method. The look-up table (LUT) based control method has robust control characteristics compared to other control methods that use linear controllers for current reference generation. However, it is impossible to store all current references under all circumstances for torque commands. General LUT based control methods use two input parameters. In order to mitigate the effect of discretely stored data, two-dimensional interpolation is used to linearly interpolate values between discontinuous data. However, because the current trajectories of PMSMs are generally ellipsoidal, an error occurs between the linearly interpolated and controllable current references. This study proposes a method to compensate for this interpolation error using a feedforward controller for rapid compensation. The improvement using the proposed method is verified by experiment and simulation. Full article
(This article belongs to the Special Issue Industrial Applications of Power Electronics)
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Open AccessArticle
Design and Analysis of a Drive System for a Series Manipulator Based on Orthogonal-Fuzzy PID Control
Electronics 2019, 8(9), 1051; https://doi.org/10.3390/electronics8091051 - 18 Sep 2019
Cited by 4 | Viewed by 658
Abstract
Because the proportional–integral–derivative (PID) parameters selected by experience are random, the control effect of fuzzy PID cannot be optimized. In order to improve the accuracy and stability of robot motion control, an orthogonal-fuzzy PID intelligent control method is proposed. In this paper, the [...] Read more.
Because the proportional–integral–derivative (PID) parameters selected by experience are random, the control effect of fuzzy PID cannot be optimized. In order to improve the accuracy and stability of robot motion control, an orthogonal-fuzzy PID intelligent control method is proposed. In this paper, the electric steering gear is used as the actuator, and the mathematical model of the servo motor joint drive system is established. The simulation analysis of the original control, PID control, fuzzy PID control, and orthogonal-fuzzy PID control of the manipulator joints in the Simulink software simulation environment and the motion control experiment of the manipulator show that using the orthogonal test method to adjust the PID parameters can quickly determine the appropriate PID parameters and greatly reduce the number of trials. The rise time, adjustment time, and overshoot of the system are significantly reduced by using fuzzy PID control, which can improve the adaptability of the system. By comparing and analyzing fuzzy PID and orthogonal-fuzzy PID control methods, it can be found that the system of orthogonal-fuzzy PID for optimal factor level combination (Kp = 0.1, Ki = 30 and Kd = 0.02) is the optimal system. The experiment results show that the orthogonal-fuzzy PID can further improve the accuracy of the system and reduce the oscillation process of the system near the steady state and make the motion more stable. Full article
(This article belongs to the Special Issue Motion Planning and Control for Robotics)
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Open AccessFeature PaperArticle
Fast Imaging of Short Perfectly Conducting Cracks in Limited-Aperture Inverse Scattering Problem
Electronics 2019, 8(9), 1050; https://doi.org/10.3390/electronics8091050 - 18 Sep 2019
Viewed by 590
Abstract
In this paper, we consider the application and analysis of subspace migration technique for a fast imaging of a set of perfectly conducting cracks with small length in two-dimensional limited-aperture inverse scattering problem. In particular, an imaging function of subspace migration with asymmetric [...] Read more.
In this paper, we consider the application and analysis of subspace migration technique for a fast imaging of a set of perfectly conducting cracks with small length in two-dimensional limited-aperture inverse scattering problem. In particular, an imaging function of subspace migration with asymmetric multistatic response matrix is designed, and its new mathematical structure is constructed in terms of an infinite series of Bessel functions and the range of incident and observation directions. This is based on the structure of left and right singular vectors linked to the nonzero singular values of MSR matrix and asymptotic expansion formula due to the existence of cracks. Investigated structure of imaging function indicates that imaging performance of subspace migration is highly related to the range of incident and observation directions. The simulation results with synthetic data polluted by random noise are exhibited to support investigated structure. Full article
(This article belongs to the Special Issue Microwave Imaging and Its Application)
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Open AccessArticle
The Study of the Operational Characteristic of Interleaved Boost Converter with Modified Coupled Inductor
Electronics 2019, 8(9), 1049; https://doi.org/10.3390/electronics8091049 - 18 Sep 2019
Cited by 1 | Viewed by 617
Abstract
In this article, design, analysis, and experimental testing of a dual interleaved boost converter with coupled inductor including demagnetizing winding are presented. Proposed topology uses the specific design of boost coils placed within the side parts of the EE core together with a [...] Read more.
In this article, design, analysis, and experimental testing of a dual interleaved boost converter with coupled inductor including demagnetizing winding are presented. Proposed topology uses the specific design of boost coils placed within the side parts of the EE core together with a demagnetizing coil located on the center part of the core. Paper describes principles of operational scenarios and characteristics. Through modification of turns ratio between boost coils and demagnetizing coil is possible to achieve high voltage gain. Consequently, the functional performance of this perspective topology is realized experimentally. For that purpose, the physical sample of converter is designed and tested in terms of efficiency considering the change of transferred power or the change of input voltage. Through modification of turns ratio between boost coils and demagnetizing coil is possible to achieve high voltage gain, therefore these dependencies are also evaluated considering also the change of the duty cycle. At the end of the paper basic operational properties are compared to standard boost topologies. It was discovered that even due to higher complexity of the proposed converter oppose to selected topologies, the operational performance is much better considering ripple of the electrical variables, efficiency, or the size of circuit components. Full article
(This article belongs to the Section Power Electronics)
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Open AccessArticle
Passive Wireless Measurement System Based on Wireless Power Transfer Technology
Electronics 2019, 8(9), 1048; https://doi.org/10.3390/electronics8091048 - 18 Sep 2019
Viewed by 753
Abstract
This paper presents a passive wireless measurement system based on wireless power transfer (WPT) technology. It does not require separate information and power transmission circuits. The data receiver only needs to send a short signal to the data collector through WPT, and then [...] Read more.
This paper presents a passive wireless measurement system based on wireless power transfer (WPT) technology. It does not require separate information and power transmission circuits. The data receiver only needs to send a short signal to the data collector through WPT, and then the information of the measured environment can be obtained by analyzing the feedback signal from the data collector. Three concepts are included in this system, namely (1) the constant oscillation period of oscillation attenuation waveforms; (2) the characteristics of inductive coupling WPT; and (3) the relationship between sensitive resistances and environmental parameters. It is very suitable for measuring the parameters in an internal or closed space. The data collector is small in size and simple in structure, and no power is needed. It has stable performance after implantation and can be used permanently. Results obtained from simulations and experiments are included. They verify the measurement process and measurement results meet the requirements of passive wireless measurement, and the measurement error is less than 1.5%. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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Open AccessFeature PaperReview
A Systematic Mapping of Translation-Enabling Technologies for Sign Languages
Electronics 2019, 8(9), 1047; https://doi.org/10.3390/electronics8091047 - 18 Sep 2019
Cited by 2 | Viewed by 968
Abstract
Sign languages (SL) are the first language for most deaf people. Consequently, bidirectional communication among deaf and non-deaf people has always been a challenging issue. Sign language usage has increased due to inclusion policies and general public agreement, which must then become evident [...] Read more.
Sign languages (SL) are the first language for most deaf people. Consequently, bidirectional communication among deaf and non-deaf people has always been a challenging issue. Sign language usage has increased due to inclusion policies and general public agreement, which must then become evident in information technologies, in the many facets that comprise sign language understanding and its computational treatment. In this study, we conduct a thorough systematic mapping of translation-enabling technologies for sign languages. This mapping has considered the most recommended guidelines for systematic reviews, i.e., those pertaining software engineering, since there is a need to account for interdisciplinary areas of accessibility, human computer interaction, natural language processing, and education, all of them part of ACM (Association for Computing Machinery) computing classification system directly related to software engineering. An ongoing development of a software tool called SYMPLE (SYstematic Mapping and Parallel Loading Engine) facilitated the querying and construction of a base set of candidate studies. A great diversity of topics has been studied over the last 25 years or so, but this systematic mapping allows for comfortable visualization of predominant areas, venues, top authors, and different measures of concentration and dispersion. The systematic review clearly shows a large number of classifications and subclassifications interspersed over time. This is an area of study in which there is much interest, with a basically steady level of scientific publications over the last decade, concentrated mainly in the European continent. The publications by country, nevertheless, usually favor their local sign language. Full article
(This article belongs to the Section Artificial Intelligence)
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Open AccessArticle
Application of L1 Trend Filtering Technology on the Current Time Domain Spectroscopy of Dielectrics
Electronics 2019, 8(9), 1046; https://doi.org/10.3390/electronics8091046 - 18 Sep 2019
Viewed by 556
Abstract
The current time domain spectroscopy of dielectrics provides important information for the analysis of dielectric properties and mechanisms. However, there is always interference during the testing process, which seriously affects the analysis of the test results. Therefore, the effective filtering of current time [...] Read more.
The current time domain spectroscopy of dielectrics provides important information for the analysis of dielectric properties and mechanisms. However, there is always interference during the testing process, which seriously affects the analysis of the test results. Therefore, the effective filtering of current time domain spectroscopy is particularly necessary. L1 trend filtering can estimate the trend items exactly in a set of time series. It has been widely used in the fields of economics and sociology. Therefore, this paper attempts to apply L1 trend filtering to the current time domain spectroscopy. Firstly, polarization and depolarization currents are measured in the laboratory. Then the test results are filtered by L1 trend filtering and the filtering effects are compared with several common filtering algorithms, such as a sliding mean filter and Savitzky–Golay smoothing filter. Finally, the robustness and time complexity of L1 trend filtering are analyzed. The filtering results show that because the polarization currents vary in a wide range of the time domain (about 2–3 orders of magnitude), smooth and undistorted curves in the whole test time range can hardly be obtained through common filtering algorithms, while they can be obtained by L1 trend filtering. The results of robustness analysis and time complexity analysis show that L1 trend filtering can extract the trend items accurately in the time series under given different noise levels, and the execution time is also lower than 176.67 s when the number of tested points is no more than 20,000. Those results show that L1 trend filtering can be applied to the time domain current spectroscopy of dielectrics. Full article
(This article belongs to the Section Circuit and Signal Processing)
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Open AccessArticle
Experimental Interference Robustness Evaluation of IEEE 802.15.4-2015 OQPSK-DSSS and SUN-OFDM Physical Layers for Industrial Communications
Electronics 2019, 8(9), 1045; https://doi.org/10.3390/electronics8091045 - 18 Sep 2019
Cited by 8 | Viewed by 784
Abstract
In this paper, we experimentally evaluate and compare the robustness against interference of the OQPSK-DSSS (Offset Quadrature Phase Shift Keying-Direct Sequence Spread Spectrum) and the SUN-OFDM (Smart Utility Network-Orthogonal Frequency Division Multiplexing) physical layers, as defined in the IEEE 802.15.4-2015 standard. The objective [...] Read more.
In this paper, we experimentally evaluate and compare the robustness against interference of the OQPSK-DSSS (Offset Quadrature Phase Shift Keying-Direct Sequence Spread Spectrum) and the SUN-OFDM (Smart Utility Network-Orthogonal Frequency Division Multiplexing) physical layers, as defined in the IEEE 802.15.4-2015 standard. The objective of this study is to provide a comprehensive analysis of the impact that different levels of interference produce on these modulations, in terms of the resulting PDR (Packet Delivery Ratio) and depending on the length of the packet being transmitted. The results show that the SUN-OFDM physical layer provides significant benefits compared to the ubiquitous OQPSK-DSSS in terms of interference robustness, regardless of the interference type and the packet length. Overall, this demonstrates the suitability of choosing the SUN-OFDM physical layer when deploying low-power wireless networks in industrial scenarios, especially taking into consideration the possibility of trading-off robustness and spectrum efficiency depending on the application requirements. Full article
(This article belongs to the Special Issue Emerging Trends in Industrial Communication)
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Open AccessArticle
Field Trials for the Characterization of Non-Intentional Emissions at Low-Voltage Grid in the Frequency Range Assigned to NB-PLC Technologies
Electronics 2019, 8(9), 1044; https://doi.org/10.3390/electronics8091044 - 18 Sep 2019
Cited by 2 | Viewed by 851
Abstract
The paper describes the results of a measurement campaign to characterize the non-intentional emissions (NIE) that are present in the low voltage section of the electrical grid, within the frequency range assigned to narrowband power line communications (NB-PLC), from 20 kHz to 500 [...] Read more.
The paper describes the results of a measurement campaign to characterize the non-intentional emissions (NIE) that are present in the low voltage section of the electrical grid, within the frequency range assigned to narrowband power line communications (NB-PLC), from 20 kHz to 500 kHz. These NIE may severely degrade the quality of the communications and, in some cases, even isolate the transmission devices. For this reason, the identification and characterization of these perturbations are important aspects for the proper performance of the smart grid services based on PLC. The proper characterization of NIE in this frequency range is a key aspect for the selection of efficient configurations to find the best trade-off between data throughput and robustness, or even for the definition of new improved error detection and correction methods. The huge number of types of NIE, together with the wide variety of grid topologies and loads distribution (density and location of homes and industrial facilities) are great challenges that complicate the thorough characterization of NIE. This work contributes with results from field trials in different scenarios, the identification of different types of NIE and the characterization both in time and frequency domains of all the registered disturbances. This contribution will be helpful for a better knowledge of the electrical grid as a transmission medium for PLC and, therefore, for evaluating the appropriateness of different robustness techniques to be applied in the next generation of smart grid services. Full article
(This article belongs to the Special Issue Advances of Power Line Communication (PLC))
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Open AccessFeature PaperArticle
A Compact 5 GHz Power Amplifier Using a Spiral Transformer for Enhanced Power Supply Rejection in 180-nm CMOS Technology
Electronics 2019, 8(9), 1043; https://doi.org/10.3390/electronics8091043 - 17 Sep 2019
Cited by 1 | Viewed by 1008
Abstract
We present a compact 5 GHz, class A power amplifier (PA) applicable for a wireless combo-chip that supports multiple radio systems in 180 nm CMOS technology. The proposed two-stage linear PA consists of a cascode input stage with a transformer-based balun, combined with [...] Read more.
We present a compact 5 GHz, class A power amplifier (PA) applicable for a wireless combo-chip that supports multiple radio systems in 180 nm CMOS technology. The proposed two-stage linear PA consists of a cascode input stage with a transformer-based balun, combined with a balancing capacitor as the load, where the single-ended signal is converted into the balanced output and a second-stage, class A push–pull amplifier with another transformer-based balun, which efficiently combines the output power differentially to drive a single-ended 50 Ω load. The proposed single-ended PA with an internal balanced configuration can achieve a power supply rejection ratio of 9.5 to 65.9 dB at 0.1 to 3.5 GHz, which is around a 12 to 37 dB improvement compared to a conventional single-ended PA with the same power gain. The results show that the proposed PA has a gain of 15.5 dB, an output-referred 1 dB gain compression point of 13 dBm, an output intercept point of 22 dBm with a 5 MHz frequency offset, an output saturated power of 15.4 dBm, and a peak power-added efficiency of 15%. The implemented PA consumes a DC current of 72 mA under 1.8 V supply. The core chip size is 0.65 mm2 without pads. Full article
(This article belongs to the Special Issue Microwave Integrated Circuits Design and Application)
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Open AccessArticle
A Novel Address Scheme for Continuous-Flow Parallel Memory-Based Real-Valued FFT Processor
Electronics 2019, 8(9), 1042; https://doi.org/10.3390/electronics8091042 - 17 Sep 2019
Cited by 2 | Viewed by 661
Abstract
In this article, we present a modified constant-geometry based signal flow graph for memory-based real-valued fast Fourier transform architecture. Without an extra permutation, the corresponding address scheme solves the memory conflict and achieves continuous-flow operation with the minimal memory and computation cycles requirement [...] Read more.
In this article, we present a modified constant-geometry based signal flow graph for memory-based real-valued fast Fourier transform architecture. Without an extra permutation, the corresponding address scheme solves the memory conflict and achieves continuous-flow operation with the minimal memory and computation cycles requirement when compared to the state-of-the-art designs. Besides, the address scheme meets the constraint of in-place operation, concurrent I/O, normal-order I/O, variable size, and parallel processing. The experimental results demonstrate the resource and frequency efficiency of the proposed address scheme. Full article
(This article belongs to the Section Circuit and Signal Processing)
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Open AccessArticle
A Novel Meander Split Power/Ground Plane Reducing Crosstalk of Traces Crossing Over
Electronics 2019, 8(9), 1041; https://doi.org/10.3390/electronics8091041 - 17 Sep 2019
Cited by 1 | Viewed by 736
Abstract
In this paper, a novel meander split power/ground plane is proposed for reducing crosstalk between parallel lines crossing over it. The working mechanism of the meander split scheme is investigated by simulations and measurements. The LC equivalent circuit and transmission line model are [...] Read more.
In this paper, a novel meander split power/ground plane is proposed for reducing crosstalk between parallel lines crossing over it. The working mechanism of the meander split scheme is investigated by simulations and measurements. The LC equivalent circuit and transmission line model are developed for modeling interactions between the meander split and the signal lines. The proposed meander structure enhances electromagnetic coupling between split planes. The capacitive coupling across the split ensures signal integrity and magnetic coupling between adjacent finger shaped structures suppresses lateral wave propagation along the split gap, which in turn helps suppress the crosstalk. The effectiveness of the meander split remains valid over very wide frequency ranges (up to 9 GHz). Experimental results show that the proposed structure improves the signal quality and reduces the near/far end crosstalk over 30 dB and 50% in the frequency domain and time domain, respectively. Full article
(This article belongs to the Special Issue Electromagnetic Interference and Compatibility)
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Open AccessFeature PaperArticle
Monitoring of the Efficiency and Conditions of Induction Motor Operations by Smart Meter Prototype Based on a LoRa Wireless Network
Electronics 2019, 8(9), 1040; https://doi.org/10.3390/electronics8091040 - 16 Sep 2019
Cited by 4 | Viewed by 1003
Abstract
The installation of smart meters in the industry to monitor induction motors (IMs) provides easy access to the measurements of the electrical and mechanical variables, which improves the installation process. Using smart meters in industry requires temporary high-resolution data to improve the energy [...] Read more.
The installation of smart meters in the industry to monitor induction motors (IMs) provides easy access to the measurements of the electrical and mechanical variables, which improves the installation process. Using smart meters in industry requires temporary high-resolution data to improve the energy efficiency (EE) and power factor (PF) of IMs. For these purposes, Long Range (LoRa) is an ideal wireless protocol for the usage in industries due to its low energy consumption. In addition, it provides secure communications and long range indoors and outdoors. LoRa avoids the need to install antennas or routers to extend coverage, as each gateway can service 300 LoRa devices with distances of up to 10 km. For this purpose, this research successfully developed a new prototype for a low-cost IM Efficiency Monitoring System using LoRa (IMEMSL). IMEMSL is based on the Arduino open-source electronic platform. It sends the acquired data through the LoRa low-power wide-area-network (LPWAN) and cloud access gateway. This document describes the hardware and software design and implementation. The experimental results are presented and discussed. Received Signal Strength Indicator (RSSI) and time on air measured endorse the use of LoRa for this type of meters. The approximate cost of the prototype was €72 and €93 for the versions without and with Global Positioning System (GPS), respectively. Full article
(This article belongs to the Special Issue Emerging Trends in Industrial Communication)
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Open AccessFeature PaperArticle
Anxiety Level Recognition for Virtual Reality Therapy System Using Physiological Signals
Electronics 2019, 8(9), 1039; https://doi.org/10.3390/electronics8091039 - 16 Sep 2019
Cited by 7 | Viewed by 1538
Abstract
Virtual reality exposure therapy (VRET) can have a significant impact towards assessing and potentially treating various anxiety disorders. One of the main strengths of VRET systems is that they provide an opportunity for a psychologist to interact with virtual 3D environments and change [...] Read more.
Virtual reality exposure therapy (VRET) can have a significant impact towards assessing and potentially treating various anxiety disorders. One of the main strengths of VRET systems is that they provide an opportunity for a psychologist to interact with virtual 3D environments and change therapy scenarios according to the individual patient’s needs. However, to do this efficiently the patient’s anxiety level should be tracked throughout the VRET session. Therefore, in order to fully use all advantages provided by the VRET system, a mental stress detection system is needed. The patient’s physiological signals can be collected with wearable biofeedback sensors. Signals like blood volume pressure (BVP), galvanic skin response (GSR), and skin temperature can be processed and used to train the anxiety level classification models. In this paper, we combine VRET with mental stress detection and highlight potential uses of this kind of VRET system. We discuss and present a framework for anxiety level recognition, which is a part of our developed cloud-based VRET system. Physiological signals of 30 participants were collected during VRET-based public speaking anxiety treatment sessions. The acquired data were used to train a four-level anxiety recognition model (where each level of ‘low’, ‘mild’, ‘moderate’, and ‘high’ refer to the levels of anxiety rather than to separate classes of the anxiety disorder). We achieved an 80.1% cross-subject accuracy (using leave-one-subject-out cross-validation) and 86.3% accuracy (using 10 × 10 fold cross-validation) with the signal fusion-based support vector machine (SVM) classifier. Full article
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Open AccessFeature PaperArticle
Performance Improvement of a Grid-Connected Inverter under Distorted Grid Voltage Using a Harmonic Extractor
Electronics 2019, 8(9), 1038; https://doi.org/10.3390/electronics8091038 - 16 Sep 2019
Cited by 1 | Viewed by 642
Abstract
This paper introduces an improved current control strategy for a grid-connected inverter system operating under distorted grid voltage conditions. Although existing current controllers for grid-connected inverters have proportional integral gains with suitable bandwidth, low-order harmonic components can be generated by distorted grid voltages. [...] Read more.
This paper introduces an improved current control strategy for a grid-connected inverter system operating under distorted grid voltage conditions. Although existing current controllers for grid-connected inverters have proportional integral gains with suitable bandwidth, low-order harmonic components can be generated by distorted grid voltages. The proposed improved current controller is established in a synchronous reference frame that rotates at harmonic frequency. The input signals for the harmonic current controller should contain only the specific harmonic components requiring suppression. Therefore, the proposed current controller uses a harmonic extractor to distinguish current signals from fundamental and specific harmonic components. The harmonic extractor retains only the relevant harmonic components for individual current controllers with high harmonic signal ratios. This paper introduces two different strategies to extract specific harmonic components for the current controller. The proposed control strategy does not require any additional hardware filter circuits and can be implemented easily by designing a suitable digital filter. When using the proposed method, grid current quality is significantly improved compared to conventional methods that do not include harmonic extractors. The effectiveness of the proposed method is verified through simulations and practical experiments. Full article
(This article belongs to the Special Issue High Power Electric Traction Systems)
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Open AccessFeature PaperReview
The Emerging Energy Internet: Architecture, Benefits, Challenges, and Future Prospects
Electronics 2019, 8(9), 1037; https://doi.org/10.3390/electronics8091037 - 15 Sep 2019
Cited by 7 | Viewed by 1121
Abstract
Energy Internet is a concept proposed to harness, control, and manage energy resources effectively, with the help of information and communication technology. It improves a reliability of the system, and provides an increased utilization of energy resources by integrating the smart grid with [...] Read more.
Energy Internet is a concept proposed to harness, control, and manage energy resources effectively, with the help of information and communication technology. It improves a reliability of the system, and provides an increased utilization of energy resources by integrating the smart grid with the Internet. A scalable and reliable information and communication architecture is a crucial factor for both the operation and management of the energy Internet. The routing or managing of electrical energy is performed through an energy router (ER), synonymous with a communication router, which routes data packets instead of energy packets. In this paper, a holistic review of the energy Internet evolution in terms of the architecture, types of ERs, and the benefits and challenges of its implementation is presented. An exhaustive summary of the designs and architectures of the different types of ERs is also presented in this paper. The benefits of the energy Internet, along with the challenges of its implementation on a large-scale distributed architecture with the inclusion of renewable energy resources, is discussed. Finally, future prospects for the energy Internet for achieving guaranteed reliability and security is presented. Full article
(This article belongs to the Special Issue Photovoltaic Systems for Sustainable Energy)
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Open AccessFeature PaperArticle
A Low-Cost and Compact Three-Dimensional Microwave Holographic Imaging System
Electronics 2019, 8(9), 1036; https://doi.org/10.3390/electronics8091036 - 15 Sep 2019
Cited by 6 | Viewed by 688
Abstract
With the significant growth in the use of non-metallic composite materials, the demands for new and robust non-destructive testing methodologies is high. Microwave imaging has attracted a lot of attention recently for such applications. This is in addition to the biomedical imaging applications [...] Read more.
With the significant growth in the use of non-metallic composite materials, the demands for new and robust non-destructive testing methodologies is high. Microwave imaging has attracted a lot of attention recently for such applications. This is in addition to the biomedical imaging applications of microwave that are also being pursued actively. Among these efforts, in this paper, we propose a compact and cost-effective three-dimensional microwave imaging system based on a fast and robust holographic technique. For this purpose, we employ narrow-band microwave data, instead of wideband data used in previous three-dimensional cylindrical holographic imaging systems. Three-dimensional imaging is accomplished by using an array of receiver antennas surrounding the object and scanning that along with a transmitter antenna over a cylindrical aperture. To achieve low cost and compact size, we employ off-the-shelf components to build a data acquisition system replacing the costly and bulky vector network analyzers. The simulation and experimental results demonstrate the satisfactory performance of the proposed imaging system. We also show the effect of number of frequencies and size of the objects on the quality of reconstructed images. Full article
(This article belongs to the Special Issue Applications of Electromagnetic Waves) Printed Edition available
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Open AccessArticle
Design and Implementation of an Arduino-Based Plug-and-Play Acquisition System for Seismic Noise Measurements
Electronics 2019, 8(9), 1035; https://doi.org/10.3390/electronics8091035 - 15 Sep 2019
Viewed by 802
Abstract
The analysis of seismic noise provides a reliable estimation of the soil properties, which supposes the starting point for the assessment of the seismic hazard. The horizontal-to-vertical spectral ratio technique calculates the resonant frequency of the soil just by using a single three-component [...] Read more.
The analysis of seismic noise provides a reliable estimation of the soil properties, which supposes the starting point for the assessment of the seismic hazard. The horizontal-to-vertical spectral ratio technique calculates the resonant frequency of the soil just by using a single three-component sensor. Array measurements require at least several vertical sensors registering simultaneously and their analysis provides an estimation of the surface waves dispersion curve. Although these methods are relatively cheaper than other geotechnical techniques, the cost of the sensors and the multi-channel data acquisition system means that small research groups cannot afford this kind of equipment. In this work, two prototypes for registering seismic noise have been developed and implemented: a three-channel acquisition system, optimized for working with three-component sensors; and a twelve-channel acquisition system, prepared for working simultaneously with twelve vertical geophones. Both prototypes are characterized by being open-hardware, open-software, easy to implement, and low-cost. The main aim is to provide a data acquisition system that can be reproduced and applied by any research group. Both developed prototypes have been tested and compared with other commercial equipment, showing their suitability to register seismic noise and to estimate the soil characteristics. Full article
(This article belongs to the Section Circuit and Signal Processing)
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Open AccessArticle
Robust Current Predictive Control-Based Equivalent Input Disturbance Approach for PMSM Drive
Electronics 2019, 8(9), 1034; https://doi.org/10.3390/electronics8091034 - 15 Sep 2019
Cited by 4 | Viewed by 865
Abstract
The implementation and experimental validation of current control strategy based on predictive control and equivalent input disturbance approach is discussed for permanent magnet synchronous motor (PMSM) control system in the paper. First, to realize the current decoupling control, the deadbeat predictive current control [...] Read more.
The implementation and experimental validation of current control strategy based on predictive control and equivalent input disturbance approach is discussed for permanent magnet synchronous motor (PMSM) control system in the paper. First, to realize the current decoupling control, the deadbeat predictive current control technique is adopted in the current loop of PMSM. Indeed, it is well known that the traditional deadbeat current control cannot completely reject the disturbance and realize the zero error current tracking control. Then, according to the model uncertainties and the parameter variations in the motor, an equivalent input disturbance approach is introduced to estimate the lump disturbance in the system, which will be used in the feed-forward compensation. Thus, a compound current controller is designed, and the proposed algorithm reduces the tracking error caused by the disturbance; the robustness of the drive system is improved effectively. Finally, simulation and experiment are accomplished on the control prototype, and the results show the effectiveness of the proposed current control algorithm. Full article
(This article belongs to the Special Issue Advanced Control Systems for Electric Drives)
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Open AccessArticle
An Efficient and Low-Power Design of the SM3 Hash Algorithm for IoT
Electronics 2019, 8(9), 1033; https://doi.org/10.3390/electronics8091033 - 14 Sep 2019
Viewed by 689
Abstract
The Internet-of-Things (IoT) has a security problem that has become increasingly significant. New architecture of SM3 which can be implemented in loT devices is proposed in this paper. The software/hardware co-design approach is put forward to implement the new architecture to achieve high [...] Read more.
The Internet-of-Things (IoT) has a security problem that has become increasingly significant. New architecture of SM3 which can be implemented in loT devices is proposed in this paper. The software/hardware co-design approach is put forward to implement the new architecture to achieve high performance and low costs. To facilitate software/hardware co-design, an AHB-SM3 interface controller (AHB-SIC) is designed as an AHB slave interface IP to exchange data with the embedded CPU. Task scheduling and hardware resource optimization techniques are adopted in the design of expansion modules. The task scheduling and critical path optimization techniques are utilized in the compression module design. The proposed architecture is implemented with ASIC using SMIC 130 nm technology. For the purpose of comparison, the proposed architecture is also implemented on Virtex 7 FPGA with a 36 MHz system clock. Compared with the standard implementation of SM3, the proposed architecture saves the number of registers for approximately 3.11 times, and 263 Mbps throughput is achieved under the 36 MHz clock. This design signifies an excellent trade-off between performance and the hardware area. Thus, the design accommodates the resource-limited IoT security devices very well. The proposed architecture is applied to an intelligent security gateway device. Full article
(This article belongs to the Section Circuit and Signal Processing)
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Open AccessArticle
Layer Selection in Progressive Transmission of Motion-Compensated JPEG2000 Video
Electronics 2019, 8(9), 1032; https://doi.org/10.3390/electronics8091032 - 13 Sep 2019
Viewed by 623
Abstract
MCJ2K (Motion-Compensated JPEG2000) is a video codec based on MCTF (Motion- Compensated Temporal Filtering) and J2K (JPEG2000). MCTF analyzes a sequence of images, generating a collection of temporal sub-bands, which are compressed with J2K. The R/D (Rate-Distortion) performance in MCJ2K is better than [...] Read more.
MCJ2K (Motion-Compensated JPEG2000) is a video codec based on MCTF (Motion- Compensated Temporal Filtering) and J2K (JPEG2000). MCTF analyzes a sequence of images, generating a collection of temporal sub-bands, which are compressed with J2K. The R/D (Rate-Distortion) performance in MCJ2K is better than the MJ2K (Motion JPEG2000) extension, especially if there is a high level of temporal redundancy. MCJ2K codestreams can be served by standard JPIP (J2K Interactive Protocol) servers, thanks to the use of only J2K standard file formats. In bandwidth-constrained scenarios, an important issue in MCJ2K is determining the amount of data of each temporal sub-band that must be transmitted to maximize the quality of the reconstructions at the client side. To solve this problem, we have proposed two rate-allocation algorithms which provide reconstructions that are progressive in quality. The first, OSLA (Optimized Sub-band Layers Allocation), determines the best progression of quality layers, but is computationally expensive. The second, ESLA (Estimated-Slope sub-band Layers Allocation), is sub-optimal in most cases, but much faster and more convenient for real-time streaming scenarios. An experimental comparison shows that even when a straightforward motion compensation scheme is used, the R/D performance of MCJ2K competitive is compared not only to MJ2K, but also with respect to other standard scalable video codecs. Full article
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Open AccessFeature PaperArticle
High-Density EEG Signal Processing Based on Active-Source Reconstruction for Brain Network Analysis in Alzheimer’s Disease
Electronics 2019, 8(9), 1031; https://doi.org/10.3390/electronics8091031 - 13 Sep 2019
Cited by 3 | Viewed by 939
Abstract
Alzheimer’s Disease (AD) is a neurological disorder characterized by a progressive deterioration of brain functions that affects, above all, older adults. It can be difficult to make an early diagnosis because its first symptoms are often associated with normal aging. Electroencephalography (EEG) can [...] Read more.
Alzheimer’s Disease (AD) is a neurological disorder characterized by a progressive deterioration of brain functions that affects, above all, older adults. It can be difficult to make an early diagnosis because its first symptoms are often associated with normal aging. Electroencephalography (EEG) can be used for evaluating the loss of brain functional connectivity in AD patients. The purpose of this paper is to study the brain network parameters through the estimation of Lagged Linear Connectivity (LLC), computed by eLORETA software, applied to High-Density EEG (HD-EEG) for 84 regions of interest (ROIs). The analysis involved three groups of subjects: 10 controls (CNT), 21 Mild Cognitive Impairment patients (MCI) and 9 AD patients. In particular, the purpose is to compare the results obtained using a 256-channel EEG, the corresponding 10–10 system 64-channel EEG and the corresponding 10–20 system 18-channel EEG, both of which are extracted from the 256-electrode configuration. The computation of the Characteristic Path Length, the Clustering Coefficient, and the Connection Density from HD-EEG configuration reveals a weakening of small-world properties of MCI and AD patients in comparison to healthy subjects. On the contrary, the variation of the network parameters was not detected correctly when we employed the standard 10–20 configuration. Only the results from HD-EEG are consistent with the expected behavior of the AD brain network. Full article
(This article belongs to the Special Issue Multidimensional Digital Signal Processing)
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