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Electronics, Volume 7, Issue 5 (May 2018)

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Cover Story (view full-size image) A 150kW single-phase 21-level solid-state transformer (SST) prototype was designed and assembled, [...] Read more.
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Open AccessArticle Implementation of a Cost-Effective Didactic Prototype for the Acquisition of Biomedical Signals
Electronics 2018, 7(5), 77; https://doi.org/10.3390/electronics7050077
Received: 19 April 2018 / Revised: 15 May 2018 / Accepted: 18 May 2018 / Published: 22 May 2018
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Abstract
This paper presents the implementation of a cost-effective didactic prototype, which was designed as a tool for theoretical and practical learning in the biomedical instrumentation area for engineering students. The prototype provides integrated hardware and software components that allow online acquisition, processing, and
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This paper presents the implementation of a cost-effective didactic prototype, which was designed as a tool for theoretical and practical learning in the biomedical instrumentation area for engineering students. The prototype provides integrated hardware and software components that allow online acquisition, processing, and visualization of electrocardiographic (ECG), electroencephalographic (EEG), electromyographic (EMG), and electrooculographic (EOG) signals, as well as measurements of bio-impedance from the skin. A control system using an Arduino Uno board and the PIC16F877A and PIC18F2550 microcontrollers was implemented. This control system allows selecting the type of module; the lead to be used in the ECG module; the input channel for the EEG, EMG, and EOG modules; and controlling the signal generator for the bioimpedance module. In addition, a graphical interface was developed in LabVIEW, in which all the acquired biomedical signals can be visualized in real time. It is highlighted as a novelty the modular implementation of the prototype, the incorporation of five modules in a single device and the graphical user-friendly interface. The final result is a low-cost device capable of processing and visualizing bioelectric signals through an interface in LabVIEW, which also allows the user to interact with each of the stages. Full article
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Open AccessArticle A Miniaturized Electromagnetic Bandgap Structure Using an Inductance-Enhanced Patch for Suppression of Parallel Plate Modes in Packages and PCBs
Electronics 2018, 7(5), 76; https://doi.org/10.3390/electronics7050076
Received: 23 April 2018 / Revised: 18 May 2018 / Accepted: 18 May 2018 / Published: 19 May 2018
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Abstract
In the packages and printed circuit boards (PCBs) of high-speed and mixed-signal electronics, parallel plate waveguides (PPWs) are frequently used as the power/ground plane pair, resulting in a significant problem of electrical switching noise such as simultaneous switching noise and ground bounce noise.
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In the packages and printed circuit boards (PCBs) of high-speed and mixed-signal electronics, parallel plate waveguides (PPWs) are frequently used as the power/ground plane pair, resulting in a significant problem of electrical switching noise such as simultaneous switching noise and ground bounce noise. This noise inevitably deteriorates system performance. In this paper, we propose an electromagnetic bandgap (EBG) structure using an inductance-enhanced patch (IEP) to suppress PPW modes in high-speed and compact packages and PCBs. The noise suppression characteristics of the proposed IEP-EBG structure were thoroughly analyzed using a dispersion diagram based on a full-wave simulation as well as an equivalent circuit model of a unit cell structure with a Floquet boundary condition. The proposed IEP-EBG structure has the advantages of substantial reductions in the low cut-off frequency of the first stopband as well as unit cell size when compared to a conventional mushroom-type EBG structure without the inductance-enhanced technique. The suppression of the PPW modes of the proposed IEP-EBG structure was verified using measurements of scattering parameters. In the measurements, the low and high cut-off frequencies of the first stopband of the IEP-EBG structure were found to be 1.55 GHz and 2.48 GHz, respectively, while those of the conventional mushroom type EBG structure were 3.52 GHz and 5.3 GHz. For the low cut-off frequency, a 56% reduction was achieved, resulting in substantial miniaturization suitable for compact packages and PCBs. Full article
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Open AccessArticle SystemC/TLM Controller for Efficient NAND Flash Management in Electronic Musical Instruments
Electronics 2018, 7(5), 75; https://doi.org/10.3390/electronics7050075
Received: 20 April 2018 / Revised: 12 May 2018 / Accepted: 16 May 2018 / Published: 18 May 2018
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Abstract
The design of an efficient memory subsystem is a fundamentally challenging task in the design of electronic equipment. The storage hierarchy chosen for a particular design has a significant impact on the overall performance and cost. Flash memory often contains the boot code,
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The design of an efficient memory subsystem is a fundamentally challenging task in the design of electronic equipment. The storage hierarchy chosen for a particular design has a significant impact on the overall performance and cost. Flash memory often contains the boot code, operating system kernel, device drivers, middleware, and other application-specific software that can result in megabytes of non-volatile stored data. To maximize the performance, data are moved from non-volatile memory to faster SDRAM (synchronous dynamic random-access memory). Non-volatile memory technologies reach a performance level close to that of dynamic RAMs with the additional benefit of persistent data storage. When cost is critical, an approach where the data are managed directly from non-volatile memory can be used. In this case the non-volatile memory subsystem is constantly accessed to retrieve data. The deep understanding of the system architecture is critical to identify any factor that affects memory performance and the resulting system performance; particularly in specific applications with stricter requests like streaming audio when more than one hundred data streams must be handled in a real-time environment and sound must be generated with a total latency of a few milliseconds. This article reports the development of the system-level model of a controller in a SystemC simulation environment capable of optimizing the use of NAND type flash memories for storage and playback of audio samples in real-time music applications, with the aim of reducing the quantity of the system SDRAM memory, thus lowering the cost of the final product, while still providing the most high-fidelity sound experience. Full article
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Open AccessArticle A 6-Bit 0.13 μm SiGe BiCMOS Digital Step Attenuator with Low Phase Variation for K-Band Applications
Electronics 2018, 7(5), 74; https://doi.org/10.3390/electronics7050074
Received: 29 March 2018 / Revised: 3 May 2018 / Accepted: 7 May 2018 / Published: 17 May 2018
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Abstract
This paper presents the design and measuring of a 6-bit SiGe BiCMOS digital step attenuator, with a maximum attenuation of 31.5 dB, and with 0.5 dB steps (64 states) that have the lowest RMS amplitude error and a low phase variation. To alleviate
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This paper presents the design and measuring of a 6-bit SiGe BiCMOS digital step attenuator, with a maximum attenuation of 31.5 dB, and with 0.5 dB steps (64 states) that have the lowest RMS amplitude error and a low phase variation. To alleviate the large phase variation of the conventional attenuator at a higher frequency, the proposed attenuator utilizes a phase compensation circuit. The phase compensation circuit consists of a 2nd order low pass phase correction network, stacked in parallel to the switched π/T structure of each attenuation module. An attenuator with a phase compensation network shows a root mean square (RMS) amplitude error less than 0.43 dB, and the RMS insertion phase deviation varying from 1.6° to 4.2° over 20–24 GHz. The measured insertion loss is 21.9 dB and the input P1dB is 14.03 dBm at 22 GHz. Our confidence regarding the obtained results stems from a comparison of simulations, carried out using Cadence Virtuoso, and physical measurements using a network analyzer (also presented). The proposed attenuator’s design has a 0.13 μm SiGe BiCMOS process, with an approximate occupied area of 1.92 × 0.4 mm2 including chip pads. Full article
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Open AccessArticle Monocular Vision SLAM-Based UAV Autonomous Landing in Emergencies and Unknown Environments
Electronics 2018, 7(5), 73; https://doi.org/10.3390/electronics7050073
Received: 17 April 2018 / Revised: 9 May 2018 / Accepted: 11 May 2018 / Published: 15 May 2018
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Abstract
With the popularization and wide application of drones in military and civilian fields, the safety of drones must be considered. At present, the failure and drop rates of drones are still much higher than those of manned aircraft. Therefore, it is imperative to
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With the popularization and wide application of drones in military and civilian fields, the safety of drones must be considered. At present, the failure and drop rates of drones are still much higher than those of manned aircraft. Therefore, it is imperative to improve the research on the safe landing and recovery of drones. However, most drone navigation methods rely on global positioning system (GPS) signals. When GPS signals are missing, these drones cannot land or recover properly. In fact, with the help of optical equipment and image recognition technology, the position and posture of the drone in three dimensions can be obtained, and the environment where the drone is located can be perceived. This paper proposes and implements a monocular vision-based drone autonomous landing system in emergencies and in unstructured environments. In this system, a novel map representation approach is proposed that combines three-dimensional features and a mid-pass filter to remove noise and construct a grid map with different heights. In addition, a region segmentation is presented to detect the edges of different-height grid areas for the sake of improving the speed and accuracy of the subsequent landing area selection. As a visual landing technology, this paper evaluates the proposed algorithm in two tasks: scene reconstruction integrity and landing location security. In these tasks, firstly, a drone scans the scene and acquires key frames in the monocular visual simultaneous localization and mapping (SLAM) system in order to estimate the pose of the drone and to create a three-dimensional point cloud map. Then, the filtered three-dimensional point cloud map is converted into a grid map. The grid map is further divided into different regions to select the appropriate landing zone. Thus, it can carry out autonomous route planning. Finally, when it stops upon the landing field, it will start the descent mode near the landing area. Experiments in multiple sets of real scenes show that the environmental awareness and the landing area selection have high robustness and real-time performance. Full article
(This article belongs to the Special Issue Autonomous Control of Unmanned Aerial Vehicles)
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Open AccessReview Review on Health Management System for Lithium-Ion Batteries of Electric Vehicles
Electronics 2018, 7(5), 72; https://doi.org/10.3390/electronics7050072
Received: 15 April 2018 / Revised: 6 May 2018 / Accepted: 10 May 2018 / Published: 15 May 2018
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Abstract
The battery is the most ideal power source of the twenty-first century, and has a bright future in many applications, such as portable consumer electronics, electric vehicles (EVs), military and aerospace systems, and power storage for renewable energy sources, because of its many
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The battery is the most ideal power source of the twenty-first century, and has a bright future in many applications, such as portable consumer electronics, electric vehicles (EVs), military and aerospace systems, and power storage for renewable energy sources, because of its many advantages that make it the most promising technology. EVs are viewed as one of the novel solutions to land transport systems, as they reduce overdependence on fossil energy. With the current growth of EVs, it calls for innovative ways of supplementing EVs power, as overdependence on electric power may add to expensive loads on the power grid. However lithium-ion batteries (LIBs) for EVs have high capacity, and large serial/parallel numbers, when coupled with problems like safety, durability, uniformity, and cost imposes limitations on the wide application of lithium-ion batteries in EVs. These LIBs face a major challenge of battery life, which research has shown can be extended by cell balancing. The common areas under which these batteries operate with safety and reliability require the effective control and management of battery health systems. A great deal of research is being carried out to see that this technology does not lead to failure in the applications, as its failure may lead to catastrophes or lessen performance. This paper, through an analytical review of the literature, gives a brief introduction to battery management system (BMS), opportunities, and challenges, and provides a future research agenda on battery health management. With issues raised in this review paper, further exploration is essential. Full article
(This article belongs to the Special Issue Applications of Power Electronics)
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Open AccessArticle The Platform Development of a Real-Time Momentum Data Collection System for Livestock in Wide Grazing Land
Electronics 2018, 7(5), 71; https://doi.org/10.3390/electronics7050071
Received: 22 April 2018 / Revised: 11 May 2018 / Accepted: 13 May 2018 / Published: 14 May 2018
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Abstract
In the process of animal husbandry production through grazing, animals are active in large grassland or mountain areas, and it is very difficult to obtain and deal with the information on animal activity and state of life. In this paper, we propose a
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In the process of animal husbandry production through grazing, animals are active in large grassland or mountain areas, and it is very difficult to obtain and deal with the information on animal activity and state of life. In this paper, we propose a platform for operation of data transmission and analysis system which gathers activity and status information of livestock. The data collected in real time from integrated livestock sensor modules are anticipated to assist farmers to supervise animal activities and health. While at the same time the improvements of viable farming techniques are expected to reduce the impact of the livestock industry on the environment. For the individual management of target livestock, the data collection system needs a convergence technology with a physical active sensor, a wireless sensor network and solar power technology to cover the wide area of mountains. We implemented a momentum data collection system to collect and transfer the information of ecological and situations of livestock in grazing, which include sensor and communication modules, repeaters with solar panels to cover the problems of communications in wide grazing and a receiver connected to main server. Besides, in order to prevent data collisions and deviations on multiple transmitter operation, we renewed the format of the communication protocol and made a platform to analyze animal activities information by software. Finally, the system and platform were applied and tested in National Rural Development Administration in Republic of Korea. Full article
(This article belongs to the Special Issue Open-Source Electronics Platforms: Development and Applications)
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Open AccessArticle Adhesion Control Strategy Based on the Wheel-Rail Adhesion State Observation for High-Speed Trains
Electronics 2018, 7(5), 70; https://doi.org/10.3390/electronics7050070
Received: 1 April 2018 / Revised: 27 April 2018 / Accepted: 10 May 2018 / Published: 14 May 2018
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Abstract
In this paper, an adhesion control strategy based on the wheel-rail adhesion state observation is proposed for high-speed trains. First, the high-speed train single axle dynamics model is established. Then, a modified adhesion control method is proposed. The scheme observes the tangential force
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In this paper, an adhesion control strategy based on the wheel-rail adhesion state observation is proposed for high-speed trains. First, the high-speed train single axle dynamics model is established. Then, a modified adhesion control method is proposed. The scheme observes the tangential force coefficient between wheel and rail through full dimension observer and forecasts the slope of the adhesion-slip curve by the recursive least squares method with forgetting factor. Meanwhile, a feasibility analysis of the method and the control parameters tuning is conducted. Afterwards, the experimental study of the proposed adhesion control is carried out based on a 5.5 kW induction motor drag platform using dSPACE simulation technology. The experimental results confirm the feasibility of the adhesion control method proposed in this paper. Using the proposed adhesion control method can achieve high wheel-rail adhesion performance under variable complex road conditions. Full article
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Open AccessArticle Methane Gas Density Monitoring and Predicting Based on RFID Sensor Tag and CNN Algorithm
Electronics 2018, 7(5), 69; https://doi.org/10.3390/electronics7050069
Received: 9 April 2018 / Revised: 4 May 2018 / Accepted: 10 May 2018 / Published: 12 May 2018
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Abstract
According to the advantages of integrating wireless sensors networks (WSN) and radio frequency identification (RFID), this paper proposes a novel method for methane gas density monitoring and predicting based on a passive RFID sensor tag and a convolutional neural networks (CNN) algorithm. The
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According to the advantages of integrating wireless sensors networks (WSN) and radio frequency identification (RFID), this paper proposes a novel method for methane gas density monitoring and predicting based on a passive RFID sensor tag and a convolutional neural networks (CNN) algorithm. The proposed wireless sensor is based on electronic product code (EPC) generation2 (G2) protocol and the sensor data is embedded into the identification (ID) information of the RFID chip. The wireless sensor consists of a communication section, radio-frequency (RF) front-end section, and digital section. The communication section is used to perform the transmission and reception of wireless signals, modulation, and demodulation. The RF front-end section is adopted to provide the stable supply voltage for other parts. The digital section is employed to achieve sensor data and control the overall operation of the wireless sensor based on EPC protocol. Because the miscellaneous noises will decrease the accuracy during the process of data wireless transmission, the CNN algorithm is adopted to extract the robust feature from raw data. The measurement results show that the exploited RFID sensor can realize a maximum communication distance of 10.3 m and can accurately measure and predict the methane gas density in an underground mine. The RFID sensor technology is a beneficial supplement to the current underground WSN monitoring system. Full article
(This article belongs to the Special Issue Unconventional RFID Systems)
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Open AccessArticle A Hierarchical Vision-Based UAV Localization for an Open Landing
Electronics 2018, 7(5), 68; https://doi.org/10.3390/electronics7050068
Received: 11 April 2018 / Revised: 5 May 2018 / Accepted: 9 May 2018 / Published: 11 May 2018
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Abstract
The localization of unmanned aerial vehicles (UAVs) for autonomous landing is challenging because the relative positions of the landing objects are almost inaccessible and the objects have nearly no transmission with UAVs. In this paper, a hierarchical vision-based localization framework for rotor UAVs
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The localization of unmanned aerial vehicles (UAVs) for autonomous landing is challenging because the relative positions of the landing objects are almost inaccessible and the objects have nearly no transmission with UAVs. In this paper, a hierarchical vision-based localization framework for rotor UAVs is proposed for an open landing. In such a hierarchical framework, the landing is defined into three phases: “Approaching”, “Adjustment”, and “Touchdown”. Object features at different scales can be extracted from a designed Robust and Quick Response Landing Pattern (RQRLP) and the corresponding detection and localization methods are introduced for the three phases. Then a federated Extended Kalman Filter (EKF) structure is costumed and utilizes the solutions of the three phases as independent measurements to estimate the pose of the vehicle. The framework can be used to integrate the vision solutions and enables the estimation to be smooth and robust. In the end, several typical field experiments have been carried out to verify the proposed hierarchical vision framework. It can be seen that a wider localization range can be extended by the proposed framework while the precision is ensured. Full article
(This article belongs to the Special Issue Nanoelectronic Materials, Devices and Modeling)
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Open AccessArticle Multi-Scroll Chaotic Attractors in SC-CNN via Hyperbolic Tangent Function
Electronics 2018, 7(5), 67; https://doi.org/10.3390/electronics7050067
Received: 9 April 2018 / Revised: 6 May 2018 / Accepted: 7 May 2018 / Published: 9 May 2018
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Abstract
A State Controlled-Cellular Neural Network (SC-CNN) based chaotic model for generating multi-scroll attractors via hyperbolic tangent function series is proposed in this paper. After presenting the double scroll generation, the presented SC-CNN system is used in multi-scroll chaotic attractor generation by adding hyperbolic
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A State Controlled-Cellular Neural Network (SC-CNN) based chaotic model for generating multi-scroll attractors via hyperbolic tangent function series is proposed in this paper. After presenting the double scroll generation, the presented SC-CNN system is used in multi-scroll chaotic attractor generation by adding hyperbolic tangent function series. By using equilibrium analysis and their stability such as Lyapunov exponent analysis, bifurcation diagrams and Poincaré map, the dynamical behaviors of the proposed system are theoretically analyzed and numerically investigated. Full article
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Open AccessArticle Blockchain-Oriented Coalition Formation by CPS Resources: Ontological Approach and Case Study
Electronics 2018, 7(5), 66; https://doi.org/10.3390/electronics7050066
Received: 15 February 2018 / Revised: 26 April 2018 / Accepted: 7 May 2018 / Published: 8 May 2018
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Abstract
Cyber-physical systems (CPS), robotics, Internet of Things, information and communication technologies have become more and more popular over the last several years. These topics open new perspectives and scenarios that can automate processes in human life. CPS are aimed at interaction support in
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Cyber-physical systems (CPS), robotics, Internet of Things, information and communication technologies have become more and more popular over the last several years. These topics open new perspectives and scenarios that can automate processes in human life. CPS are aimed at interaction support in information space for physical entities communicated in physical space in real time. At the same time the blockchain technology that becomes popular last years allows to organize immutable distributed database that store all significant information and provide access for CPS participants. The paper proposes an approach that is based on ontology-based context management, publish/subscribe semantic interoperability support, and blockchain techniques. Utilization of these techniques provide possibilities to develop CPS that supports dynamic, distributed, and stable coalition formation of the resources. The case study presented has been implemented for the scenario of heterogeneous mobile robots’ collaboration for the overcoming of obstacles. There are two types of robots and an information service participating in the scenario. Evaluation shows that the proposed approach is applicable for the presented class of scenarios. Full article
(This article belongs to the Special Issue Open-Source Electronics Platforms: Development and Applications)
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Open AccessArticle PrECast: An Efficient Crypto-Free Solution for Broadcast-Based Attacks in IPv4 Networks
Electronics 2018, 7(5), 65; https://doi.org/10.3390/electronics7050065
Received: 31 March 2018 / Revised: 4 May 2018 / Accepted: 4 May 2018 / Published: 8 May 2018
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Abstract
Broadcasting is one of the essential features in the Internet Protocol Ver 4 (IPv4). Attackers often exploit this feature of the IP protocol to launch several attacks against a network or an individual host. Attackers may either be a part of a Local
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Broadcasting is one of the essential features in the Internet Protocol Ver 4 (IPv4). Attackers often exploit this feature of the IP protocol to launch several attacks against a network or an individual host. Attackers may either be a part of a Local Area Network (LAN) or outside a LAN to launch these attacks. There are numerous papers available in the literature to solve problems resulting from IP broadcasting. However, all these solutions target a specific problem that results from IP broadcasting. Furthermore, these solutions use either a computationally-intensive cryptographic scheme, the a priori relation between the host and the network or a modified protocol stack at every host. In this paper, we provide a seamless and transparent solution to eliminate IP broadcasting and thus eliminate all problems related to IP broadcasting. Our proposed solution is crypto-free and does not need any modification to the protocol stack. Full article
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Open AccessArticle Two-Dimensional (2D) Slices Encryption-Based Security Solution for Three-Dimensional (3D) Printing Industry
Electronics 2018, 7(5), 64; https://doi.org/10.3390/electronics7050064
Received: 22 April 2018 / Revised: 30 April 2018 / Accepted: 2 May 2018 / Published: 7 May 2018
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Abstract
Nowadays, three-dimensional (3D) printing technology is applied to many areas of life and changes the world based on the creation of complex structures and shapes that were not feasible in the past. But, the data of 3D printing is often attacked in the
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Nowadays, three-dimensional (3D) printing technology is applied to many areas of life and changes the world based on the creation of complex structures and shapes that were not feasible in the past. But, the data of 3D printing is often attacked in the storage and transmission processes. Therefore, 3D printing must be ensured security in the manufacturing process, especially the data of 3D printing to prevent attacks from hackers. This paper presents a security solution for 3D printing based on two-dimensional (2D) slices encryption. The 2D slices of 3D printing data is encrypted in the frequency domain or in the spatial domain by the secret key to generate the encrypted data of 3D printing. We implemented the proposed solution in both the frequency domain based on the Discrete Cosine Transform and the spatial domain based on geometric transform. The entire 2D slices of 3D printing data is altered and secured after the encryption process. The proposed solution is responsive to the security requirements for the secured storage and transmission. Experimental results also verified that the proposed solution is effective to 3D printing data and is independent on the format of 3D printing models. When compared to the conventional works, the security and performance of the proposed solution is also better. Full article
(This article belongs to the Special Issue Safe and Secure Embedded Systems)
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Open AccessArticle A Novel Supercapacitor/Lithium-Ion Hybrid Energy System with a Fuzzy Logic-Controlled Fast Charging and Intelligent Energy Management System
Electronics 2018, 7(5), 63; https://doi.org/10.3390/electronics7050063
Received: 25 April 2018 / Revised: 1 May 2018 / Accepted: 2 May 2018 / Published: 4 May 2018
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Abstract
The electric powered wheelchair (EPW) is an essential assistive tool for people with serious injuries or disability. This manuscript describes the validation of applied research for reducing the charging time of an electric wheelchair using a hybrid electric system (HES) composed of a
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The electric powered wheelchair (EPW) is an essential assistive tool for people with serious injuries or disability. This manuscript describes the validation of applied research for reducing the charging time of an electric wheelchair using a hybrid electric system (HES) composed of a supercapacitor (SC) bank and a lithium-ion battery with a fuzzy logic controller (FLC)-based fast charging system for Li-ion batteries and a fuzzy logic-based intelligent energy management system (FLIEMS) for controlling the power flow within the HES. The fast charging FLC was designed to drive the voltage difference (Vd) among the different cells of a multi-cell battery and the cell voltage (Vc) of an individual cell. These parameters (voltage difference and cell voltage) were used as input voltages to reduce the charge time and activate a bypass equalization (BPE) scheme. BPE was introduced in this paper so that the battery operates within the safe voltage range. For SC/Li-ion HES, the FLIEMS presented in this paper controls the bi-directional power flow to smooth the power extracted from Li-ion batteries. Moreover, a dual active bridge isolated bidirectional DC converter (DAB-IBDC) was used for power conversion. The DAB-IBDC presented in this paper has the characteristics of galvanic isolation, and high power conversion efficiency compared to the conventional converter circuits due to the reduced reverse power flow and current stresses. Full article
(This article belongs to the Special Issue Hardware and Architecture)
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Open AccessFeature PaperArticle Implementation of a Single-Phase SST for the Interface between a 13.2 kV MVAC Network and a 750 V Bipolar DC Distribution
Electronics 2018, 7(5), 62; https://doi.org/10.3390/electronics7050062
Received: 12 April 2018 / Revised: 29 April 2018 / Accepted: 30 April 2018 / Published: 4 May 2018
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Abstract
This paper presents the implementation of a single-phase solid-state transformer (SST) for the interface between a 13.2 kV medium voltage alternative current (MVAC) network and a 750 V bipolar DC distribution. The SST has ten cascaded subunits in consideration of the device rating
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This paper presents the implementation of a single-phase solid-state transformer (SST) for the interface between a 13.2 kV medium voltage alternative current (MVAC) network and a 750 V bipolar DC distribution. The SST has ten cascaded subunits in consideration of the device rating and modulation index (MI). Each subunit consists of an AC/DC stage and a DC/DC stage with a high frequency isolated transformer (HFIT). The AC/DC stage consists of cascaded H-bridges (CHBs) to cope with the MVAC. The DC/DC stage employs a triple active bridge (TAB) converter for bipolar DC distribution. Topology analysis and controller design for this specific structure are discussed. In addition, the insulation of HFIT used in DC/DC converters is also discussed. A simple balancing controller at the AC/DC stage and a current sharing controller at the DC/DC stage are used to prevent DC-link voltage unbalance caused by the cascaded structure. The discussions are validated using a 150 kW single-phase 21-level SST prototype at the laboratory level. Full article
(This article belongs to the Special Issue Renewable Electric Energy Systems)
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Open AccessArticle Bagged Decision Trees Based Scheme of Microgrid Protection Using Windowed Fast Fourier and Wavelet Transforms
Electronics 2018, 7(5), 61; https://doi.org/10.3390/electronics7050061
Received: 29 March 2018 / Revised: 27 April 2018 / Accepted: 1 May 2018 / Published: 3 May 2018
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Abstract
Microgrids of varying size and applications are regarded as a key feature of modernizing the power system. The protection of those systems, however, has become a major challenge and a popular research topic because it involves greater complexity than traditional distribution systems. This
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Microgrids of varying size and applications are regarded as a key feature of modernizing the power system. The protection of those systems, however, has become a major challenge and a popular research topic because it involves greater complexity than traditional distribution systems. This paper addresses this issue through a novel approach which utilizes detailed analysis of current and voltage waveforms through windowed fast Fourier and wavelet transforms. The fault detection scheme involves bagged decision trees which use input features extracted from the signal processing stage which are selected by correlation analysis. The technique was tested on a microgrid model developed using PSCAD/EMTDS, which is inspired from an operational microgrid in Goldwind Science Technology Co. Ltd., in Beijing, China. The results showed a great level of effectiveness to accurately identify faults from other non-fault disturbances, precisely locating the fault and trigger opening of the right circuit breaker/s under different operation modes, fault resistances, and other system disturbances. Full article
(This article belongs to the Special Issue Renewable Electric Energy Systems)
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Open AccessArticle Evaluation of LDMOS Figure of Merit Using Device Simulation
Electronics 2018, 7(5), 60; https://doi.org/10.3390/electronics7050060
Received: 16 March 2018 / Revised: 21 April 2018 / Accepted: 26 April 2018 / Published: 29 April 2018
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Abstract
The benefit of the super-junction (SJ) technique at the low-voltage (30 V) range is investigated in this work. Optimizations such as adding a buffer layer to the device have been used, but simulation and theoretical evidences show that the benefits of the SJ
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The benefit of the super-junction (SJ) technique at the low-voltage (30 V) range is investigated in this work. Optimizations such as adding a buffer layer to the device have been used, but simulation and theoretical evidences show that the benefits of the SJ technique are marginal for 30 V applications. The floating P structure proved to be a good replacement for SJ devices at the 30 V range due to a simpler fabrication process as well as performance gains achieved with optimization. Also, a new idea of combining the floating P layer with a shallow trench isolation layer is proposed and simulated using TCAD, yielding the figure of merit (RDS(on) × QG) of 5.93 mΩ-nC, which is a 39% improvement on the standard floating P device. Full article
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Open AccessArticle Radar Waveform Recognition Based on Time-Frequency Analysis and Artificial Bee Colony-Support Vector Machine
Electronics 2018, 7(5), 59; https://doi.org/10.3390/electronics7050059
Received: 28 March 2018 / Revised: 20 April 2018 / Accepted: 24 April 2018 / Published: 27 April 2018
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Abstract
In this paper, a system for identifying eight kinds of radar waveforms is explored. The waveforms are the binary phase shift keying (BPSK), Costas codes, linear frequency modulation (LFM) and polyphase codes (including P1, P2, P3, P4 and Frank codes). The features of
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In this paper, a system for identifying eight kinds of radar waveforms is explored. The waveforms are the binary phase shift keying (BPSK), Costas codes, linear frequency modulation (LFM) and polyphase codes (including P1, P2, P3, P4 and Frank codes). The features of power spectral density (PSD), moments and cumulants, instantaneous properties and time-frequency analysis are extracted from the waveforms and three new features are proposed. The classifier is support vector machine (SVM), which is optimized by artificial bee colony (ABC) algorithm. The system shows well robustness, excellent computational complexity and high recognition rate under low signal-to-noise ratio (SNR) situation. The simulation results indicate that the overall recognition rate is 92% when SNR is −4 dB. Full article
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Open AccessArticle Wireless Power Transfer System for Rotary Parts Telemetry of Gas Turbine Engine
Electronics 2018, 7(5), 58; https://doi.org/10.3390/electronics7050058
Received: 19 March 2018 / Revised: 17 April 2018 / Accepted: 17 April 2018 / Published: 27 April 2018
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Abstract
A novel wireless power transfer approach for the rotary parts telemetry of a gas turbine engine is proposed. The advantages of a wireless power transfer (WPT) system in the power supply for the rotary parts telemetry of a gas turbine engine are introduced.
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A novel wireless power transfer approach for the rotary parts telemetry of a gas turbine engine is proposed. The advantages of a wireless power transfer (WPT) system in the power supply for the rotary parts telemetry of a gas turbine engine are introduced. By simplifying the circuit of the inductively-coupled WPT system and developing its equivalent circuit model, the mathematical expressions of transfer efficiency and transfer power of the system are derived. A mutual inductance model between receiving and transmitting coils of the WPT system is presented and studied. According to this model, the mutual inductance between the receiving and the transmitting coils can be calculated at different axial distances. Then, the transfer efficiency and transfer power can be calculated as well. Based on the test data, the relationship of the different distances between the two coils, the transfer efficiency, and transfer power is derived. The proper positions where the receiving and transmitting coils are installed in a gas turbine engine are determined under conditions of satisfying the transfer efficiency and transfer power that the telemetry system required. Full article
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Open AccessArticle All-in-One Wafer-Level Solution for MMIC Automatic Testing
Electronics 2018, 7(5), 57; https://doi.org/10.3390/electronics7050057
Received: 7 April 2018 / Revised: 20 April 2018 / Accepted: 23 April 2018 / Published: 26 April 2018
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Abstract
In this paper, we present an all-in-one wafer-level solution for MMIC (monolithic microwave integrated circuit) automatic testing. The OSL (open short load) two tier de-embedding, the calibration verification model, the accurate PAE (power added efficiency) testing, and the optimized vector cold source NF
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In this paper, we present an all-in-one wafer-level solution for MMIC (monolithic microwave integrated circuit) automatic testing. The OSL (open short load) two tier de-embedding, the calibration verification model, the accurate PAE (power added efficiency) testing, and the optimized vector cold source NF (noise figure) measurement techniques are integrated in this solution to improve the measurement accuracy. A dual-core topology formed by an IPC (industrial personal computer) and a VNA (vector network analyzer), and an automatic test software based on a three-level driver architecture, are applied to enhance the test efficiency. The benefit from this solution is that all the data of a MMIC can be achieved in only one contact, which shows state-of-the-art accuracy and efficiency. Full article
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Open AccessArticle Energy Reduction Multipath Routing Protocol for MANET Using Recoil Technique
Electronics 2018, 7(5), 56; https://doi.org/10.3390/electronics7050056
Received: 15 March 2018 / Revised: 21 April 2018 / Accepted: 23 April 2018 / Published: 25 April 2018
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Abstract
In Mobile Ad-hoc networks (MANET), power conservation and utilization is an acute problem and has received significant attention from academics and industry in recent years. Nodes in MANET function on battery power, which is a rare and limited energy resource. Hence, its conservation
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In Mobile Ad-hoc networks (MANET), power conservation and utilization is an acute problem and has received significant attention from academics and industry in recent years. Nodes in MANET function on battery power, which is a rare and limited energy resource. Hence, its conservation and utilization should be done judiciously for the effective functioning of the network. In this paper, a novel protocol namely Energy Reduction Multipath Routing Protocol for MANET using Recoil Technique (AOMDV-ER) is proposed, which conserves the energy along with optimal network lifetime, routing overhead, packet delivery ratio and throughput. It performs better than any other AODV based algorithms, as in AOMDV-ER the nodes transmit packets to their destination smartly by using a varying recoil off time technique based on their geographical location. This concept reduces the number of transmissions, which results in the improvement of network lifetime. In addition, the local level route maintenance reduces the additional routing overhead. Lastly, the prediction based link lifetime of each node is estimated which helps in reducing the packet loss in the network. This protocol has three subparts: an optimal route discovery algorithm amalgamation with the residual energy and distance mechanism; a coordinated recoiled nodes algorithm which eliminates the number of transmissions in order to reduces the data redundancy, traffic redundant, routing overhead, end to end delay and enhance the network lifetime; and a last link reckoning and route maintenance algorithm to improve the packet delivery ratio and link stability in the network. The experimental results show that the AOMDV-ER protocol save at least 16% energy consumption, 12% reduction in routing overhead, significant achievement in network lifetime and packet delivery ratio than Ad hoc on demand multipath distance vector routing protocol (AOMDV), Ad hoc on demand multipath distance vector routing protocol life maximization (AOMR-LM) and Source routing-based multicast protocol (SRMP) algorithms. Hence, the AOMDV-ER algorithm performs better than these recently developed algorithms. Full article
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