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Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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8 pages, 1121 KiB  
Review
Radio over Fiber: An Alternative Broadband Network Technology for IoT
by Diego F. Paredes-Páliz, Guillermo Royo, Francisco Aznar, Concepción Aldea and Santiago Celma
Electronics 2020, 9(11), 1785; https://doi.org/10.3390/electronics9111785 - 27 Oct 2020
Cited by 23 | Viewed by 5098
Abstract
Wireless broadband access networks have been positioning themselves as a good solution for manufacturers and users of IoT (internet of things) devices, due mainly to the high data transfer rate required over terminal devices without restriction of information format. In this work, a [...] Read more.
Wireless broadband access networks have been positioning themselves as a good solution for manufacturers and users of IoT (internet of things) devices, due mainly to the high data transfer rate required over terminal devices without restriction of information format. In this work, a review of two Radio over Fiber strategies is presented. Both have excellent performance and even offer the possibility to extend wireless area coverage where mobile networks do not reach or the 802.11 network presents issues. Radio Frequency over Fiber (RFoF) and intermediate Frequency over Fiber (IFoF) are two transmission strategies compatible with the required new broadband services and both play a key role in the design of the next generation integrated optical–wireless networks, such as 5G and Satcom networks, including on RAU (Remote Antenna Unit) new functionalities to improve their physical dimensions, employing a microelectronic layout over nanometric technologies. Full article
(This article belongs to the Section Networks)
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13 pages, 2780 KiB  
Article
A Design of a Dual-Band Bandpass Filter Based on Modal Analysis for Modern Communication Systems
by Ali Lalbakhsh, Seyed Morteza Alizadeh, Amirhossein Ghaderi, Alireza Golestanifar, Bahare Mohamadzade, Mohammad (Behdad) Jamshidi, Kaushik Mandal and Wahab Mohyuddin
Electronics 2020, 9(11), 1770; https://doi.org/10.3390/electronics9111770 - 26 Oct 2020
Cited by 63 | Viewed by 4942
Abstract
A dual-band bandpass filter (BPF) composed of a coupling structure and a bent T-shaped resonator loaded by small L-shaped stubs is presented in this paper. The first band of the proposed BPF covers 4.6 to 10.6 GHz, showing 78.9% fractional bandwidth (FBW) at [...] Read more.
A dual-band bandpass filter (BPF) composed of a coupling structure and a bent T-shaped resonator loaded by small L-shaped stubs is presented in this paper. The first band of the proposed BPF covers 4.6 to 10.6 GHz, showing 78.9% fractional bandwidth (FBW) at 7.6 GHz, and the second passband is cantered at 11.5 GHz with a FBW of 2.34%. The bent T-shaped resonator generates two transmission zeros (TZs) near the wide passband edges, which are used to tune the bandwidth of the first band, and the L-shaped stubs are used to create and control the narrow passband. The selectivity performance of the BPF is analyzed using the transfer function extracted from the lumped circuit model verified by a detailed even/odd mode analysis. The BPF presents a flat group delay (GD) of 0.45 ns and an insertion loss (IL) less than 0.6 dB in the wide passband and a 0.92 IL in the narrow passband. A prototype of the proposed BPF is fabricated and tested, showing very good agreement between the numerically predicted and measured results. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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12 pages, 3364 KiB  
Article
Cost-Effective High-Performance Digital Control Method in Series-Series Compensated Wireless Power Transfer System
by Hojoon Shin, Euihoon Chung and Jung-Ik Ha
Electronics 2020, 9(11), 1772; https://doi.org/10.3390/electronics9111772 - 26 Oct 2020
Cited by 3 | Viewed by 2753
Abstract
This paper proposes a control method for a digital signal processor based series-series (SS) compensated wireless power transfer system. In the control method, load resistance and mutual inductance are identified simultaneously, and output voltage can be estimated by using only the primary side [...] Read more.
This paper proposes a control method for a digital signal processor based series-series (SS) compensated wireless power transfer system. In the control method, load resistance and mutual inductance are identified simultaneously, and output voltage can be estimated by using only the primary side voltage and current without direct feedback from the secondary side circuit. Since this estimation method requires a complex mathematical calculation procedure, a digital signal processor is used in this system. One of the major disadvantages of using a digital controller in this system is a limitation of sampling rates. Therefore, in this paper, several current reconstruction methods with limited sampling rates are investigated and applied. As a result, this controller not only reduces the cost of the system but also shows good estimation performance within the limited digital controller unit resource. The proposed control concept is verified by experimental results with a 48W laboratory prototype. Full article
(This article belongs to the Special Issue High Performance Power Converters: Design, Control, Devices and Applications)
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21 pages, 12694 KiB  
Article
A Deep Learning Instance Segmentation Approach for Global Glomerulosclerosis Assessment in Donor Kidney Biopsies
by Nicola Altini, Giacomo Donato Cascarano, Antonio Brunetti, Irio De Feudis, Domenico Buongiorno, Michele Rossini, Francesco Pesce, Loreto Gesualdo and Vitoantonio Bevilacqua
Electronics 2020, 9(11), 1768; https://doi.org/10.3390/electronics9111768 - 25 Oct 2020
Cited by 32 | Viewed by 4095
Abstract
The histological assessment of glomeruli is fundamental for determining if a kidney is suitable for transplantation. The Karpinski score is essential to evaluate the need for a single or dual kidney transplant and includes the ratio between the number of sclerotic glomeruli and [...] Read more.
The histological assessment of glomeruli is fundamental for determining if a kidney is suitable for transplantation. The Karpinski score is essential to evaluate the need for a single or dual kidney transplant and includes the ratio between the number of sclerotic glomeruli and the overall number of glomeruli in a kidney section. The manual evaluation of kidney biopsies performed by pathologists is time-consuming and error-prone, so an automatic framework to delineate all the glomeruli present in a kidney section can be very useful. Our experiments have been conducted on a dataset provided by the Department of Emergency and Organ Transplantations (DETO) of Bari University Hospital. This dataset is composed of 26 kidney biopsies coming from 19 donors. The rise of Convolutional Neural Networks (CNNs) has led to a realm of methods which are widely applied in Medical Imaging. Deep learning techniques are also very promising for the segmentation of glomeruli, with a variety of existing approaches. Many methods only focus on semantic segmentation—which consists in segmentation of individual pixels—or ignore the problem of discriminating between non-sclerotic and sclerotic glomeruli, so these approaches are not optimal or inadequate for transplantation assessment. In this work, we employed an end-to-end fully automatic approach based on Mask R-CNN for instance segmentation and classification of glomeruli. We also compared the results obtained with a baseline based on Faster R-CNN, which only allows detection at bounding boxes level. With respect to the existing literature, we improved the Mask R-CNN approach in sliding window contexts, by employing a variant of the Non-Maximum Suppression (NMS) algorithm, which we called Non-Maximum-Area Suppression (NMAS). The obtained results are very promising, leading to improvements over existing literature. The baseline Faster R-CNN-based approach obtained an F-Measure of 0.904 and 0.667 for non-sclerotic and sclerotic glomeruli, respectively. The Mask R-CNN approach has a significant improvement over the baseline, obtaining an F-Measure of 0.925 and 0.777 for non-sclerotic and sclerotic glomeruli, respectively. The proposed method is very promising for the instance segmentation and classification of glomeruli, and allows to make a robust evaluation of global glomerulosclerosis. We also compared Karpinski score obtained with our algorithm to that obtained with pathologists’ annotations to show the soundness of the proposed workflow from a clinical point of view. Full article
(This article belongs to the Special Issue Bioelectronic Technologies and Artificial Intelligence for Medical Diagnosis and Healthcare)
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15 pages, 4277 KiB  
Article
Design and Implementation of an Accelerated Error Convergence Criterion for Norm Optimal Iterative Learning Controller
by Saleem Riaz, Hui Lin and Muhammad Pervez Akhter
Electronics 2020, 9(11), 1766; https://doi.org/10.3390/electronics9111766 - 23 Oct 2020
Cited by 20 | Viewed by 3195
Abstract
Designing an optimal iterative learning control is a huge challenge for linear and nonlinear dynamic systems. For such complex systems, standard Norm optimal iterative learning control (NOILC) is an important consideration. This paper presents a novel NOILC error convergence technique for a discrete-time [...] Read more.
Designing an optimal iterative learning control is a huge challenge for linear and nonlinear dynamic systems. For such complex systems, standard Norm optimal iterative learning control (NOILC) is an important consideration. This paper presents a novel NOILC error convergence technique for a discrete-time method. The primary effort of the controller is to converge the error efficiently and quickly in an optimally successful way. A new iterative learning algorithm based on feedback based on reliability against input disruption was proposed in this paper. The illustration of the simulations authenticates the process suggested. The numerical example simulated on MATLAB@2019 and the mollified results affirm the validation of the designed algorithm. Full article
(This article belongs to the Special Issue Control Applications and Learning)
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16 pages, 4139 KiB  
Article
Multi-Sensor Validation Approach of an End-Effector-Based Robot for the Rehabilitation of the Upper and Lower Limb
by Cinzia Amici, Federica Ragni, Manuela Ghidoni, Davide Fausti, Luciano Bissolotti and Monica Tiboni
Electronics 2020, 9(11), 1751; https://doi.org/10.3390/electronics9111751 - 22 Oct 2020
Cited by 26 | Viewed by 3327
Abstract
End-effector-based robots are widely adopted by physiotherapists and caregivers as support in the delivery of the rehabilitation training to the patient. The validation of these devices presents critical aspects, since the system performance must be assessed analyzing the movement performed by the subject [...] Read more.
End-effector-based robots are widely adopted by physiotherapists and caregivers as support in the delivery of the rehabilitation training to the patient. The validation of these devices presents critical aspects, since the system performance must be assessed analyzing the movement performed by the subject limb, i.e., elements outside the device. This paper presents a multi-sensor approach for the validation of an innovative end-effector-based device, comparing different measurement strategies for evaluating the system effectiveness in imposing an expected training. The study was performed monitoring the movement induced by the device on the upper limb of a young male healthy subject during a set of fictitious rehabilitation sessions. The kinematic structure of the device is characterized by a compact differential mechanism with two degrees of freedom. A sequence of repetitions of a planar reaching pattern was analyzed as illustrative training task. A kinematic model of subject and system was developed, and the kinematics of a set of specific landmark points on the subject limb was evaluated. Data obtained from two measurement systems were compared: (1) an optoelectronic system with two cameras and eight skin passive markers, and (2) two triaxial accelerometers. Results were analyzed in MATLAB and R environment, revealing a high repeatability of the limb movement. Although both the measurement systems allow evaluating the acceleration of subject’s arm and forearm, accelerometers should be preferred for punctual analysis, like components optimizations, whereas optical markers provide a general overview of the system, particularly suitable for the functional design process. Full article
(This article belongs to the Special Issue Advanced Modelling and Control of Complex Nonlinear Mechatronic Systems)
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14 pages, 2636 KiB  
Article
Frequency and Voltage Supports by Battery-Fed Smart Inverters in Mixed-Inertia Microgrids
by Mohsen S. Pilehvar and Behrooz Mirafzal
Electronics 2020, 9(11), 1755; https://doi.org/10.3390/electronics9111755 - 22 Oct 2020
Cited by 14 | Viewed by 3373
Abstract
This paper presents a piecewise linear-elliptic (PLE) droop control scheme to improve the dynamic behavior of islanded microgrids. Islanded microgrids are typically vulnerable to voltage and frequency fluctuations, particularly if a combination of high- and low-inertia power generation units are used in a [...] Read more.
This paper presents a piecewise linear-elliptic (PLE) droop control scheme to improve the dynamic behavior of islanded microgrids. Islanded microgrids are typically vulnerable to voltage and frequency fluctuations, particularly if a combination of high- and low-inertia power generation units are used in a microgrid. The intermittent nature of renewable energy sources can cause sudden power mismatches, and thus, voltage and frequency fluctuations. The proposed PLE droop control scheme can be employed in a battery energy storage system (BESS) to effectively mitigate voltage and frequency fluctuations in an islanded microgrid. Though the PLE shape can be implemented for any droop control scheme, it has been applied for active power-frequency (P-f) and reactive power-voltage (Q-v) droops in this paper. In addition, the dynamic response of a battery-fed smart inverter equipped with the proposed PLE droops has been compared with the results obtained from a linear droop control scheme in an islanded microgrid containing high- and low-inertia power-generation units. In this paper, the results of several case studies are presented to confirm the capability of the PLE droop control in mitigating voltage and frequency fluctuations in islanded microgrids. Full article
(This article belongs to the Special Issue Smart Inverters in Power Grids and Renewable Energy Systems)
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16 pages, 3356 KiB  
Article
Blockchain Use in IoT for Privacy-Preserving Anti-Pandemic Home Quarantine
by Jinxin Zhang and Meng Wu
Electronics 2020, 9(10), 1746; https://doi.org/10.3390/electronics9101746 - 21 Oct 2020
Cited by 34 | Viewed by 4494
Abstract
The outbreak of the respiratory disease caused by the new coronavirus (COVID-19) has caused the world to face an existential health crisis. To contain the infectious disease, many countries have quarantined their citizens for several weeks to months and even suspended most economic [...] Read more.
The outbreak of the respiratory disease caused by the new coronavirus (COVID-19) has caused the world to face an existential health crisis. To contain the infectious disease, many countries have quarantined their citizens for several weeks to months and even suspended most economic activities. To track the movements of residents, the governments of many states have adopted various novel technologies. Connecting billions of sensors and devices over the Internet, the so-called Internet of Things (IoT), has been used for outbreak control. However, these technologies also pose serious privacy risks and security concerns with regards to data transmission and storage. In this paper, we propose a blockchain-based system to provide the secure management of home quarantine. The privacy and security attributes for various events are based on advanced cryptographic primitives. To demonstrate the application of the system, we provide a case study in an IoT system with a desktop computer, laptop, Raspberry Pi single-board computer, and the Ethereum smart contract platform. The obtained results prove its ability to satisfy security, efficiency, and low-cost requirements. Full article
(This article belongs to the Special Issue Emerging Technologies for Computer, Electrical and Systems Engineering)
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18 pages, 5214 KiB  
Article
Neural Network-Based Aircraft Conflict Prediction in Final Approach Maneuvers
by Rafael Casado and Aurelio Bermúdez
Electronics 2020, 9(10), 1708; https://doi.org/10.3390/electronics9101708 - 18 Oct 2020
Cited by 11 | Viewed by 4029
Abstract
Conflict detection and resolution is one of the main topics in air traffic management. Traditional approaches to this problem use all the available information to predict future aircraft trajectories. In this work, we propose the use of a neural network to determine whether [...] Read more.
Conflict detection and resolution is one of the main topics in air traffic management. Traditional approaches to this problem use all the available information to predict future aircraft trajectories. In this work, we propose the use of a neural network to determine whether a particular configuration of aircraft in the final approach phase will break the minimum separation requirements established by aviation rules. To achieve this, the network must be effectively trained with a large enough database, in which configurations are labeled as leading to conflict or not. We detail the way in which this training database has been obtained and the subsequent neural network design and training process. Results show that a simple network can provide a high accuracy, and therefore, we consider that it may be the basis of a useful decision support tool for both air traffic controllers and airborne autonomous navigation systems. Full article
(This article belongs to the Special Issue Autonomous Navigation Systems: Design, Control and Applications)
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25 pages, 1493 KiB  
Article
Slicing the Core Network and Radio Access Network Domains through Intent-Based Networking for 5G Networks
by Khizar Abbas, Muhammad Afaq, Talha Ahmed Khan, Adeel Rafiq and Wang-Cheol Song
Electronics 2020, 9(10), 1710; https://doi.org/10.3390/electronics9101710 - 18 Oct 2020
Cited by 54 | Viewed by 10478
Abstract
The fifth-generation mobile network presents a wide range of services which have different requirements in terms of performance, bandwidth, reliability, and latency. The legacy networks are not capable to handle these diverse services with the same physical infrastructure. In this way, network virtualization [...] Read more.
The fifth-generation mobile network presents a wide range of services which have different requirements in terms of performance, bandwidth, reliability, and latency. The legacy networks are not capable to handle these diverse services with the same physical infrastructure. In this way, network virtualization presents a reliable solution named network slicing that supports service heterogeneity and provides differentiated resources to each service. Network slicing enables network operators to create multiple logical networks over a common physical infrastructure. In this research article, we have designed and implemented an intent-based network slicing system that can slice and manage the core network and radio access network (RAN) resources efficiently. It is an automated system, where users just need to provide higher-level network configurations in the form of intents/contracts for a network slice, and in return, our system deploys and configures the requested resources accordingly. Further, our system grants the automation of the network configurations process and reduces the manual effort. It has an intent-based networking (IBN) tool which can control, manage, and monitor the network slice resources properly. Moreover, a deep learning model, the generative adversarial neural network (GAN), has been used for the management of network resources. Several tests have been carried out with our system by creating three slices, which shows better performance in terms of bandwidth and latency. Full article
(This article belongs to the Special Issue Radio Access Network Planning and Management)
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19 pages, 934 KiB  
Article
Requirements for Validation of Dynamic Wind Turbine Models: An International Grid Code Review
by Raquel Villena-Ruiz, Andrés Honrubia-Escribano, Francisco Jiménez-Buendía, Ángel Molina-García and Emilio Gómez-Lázaro
Electronics 2020, 9(10), 1707; https://doi.org/10.3390/electronics9101707 - 17 Oct 2020
Cited by 9 | Viewed by 3919
Abstract
Wind power is positioned as one of the fastest-growing energy sources today, while also being a mature technology with a strong capacity for creating employment and guaranteeing environmental sustainability. However, the stochastic nature of wind may affect the integration of power plants into [...] Read more.
Wind power is positioned as one of the fastest-growing energy sources today, while also being a mature technology with a strong capacity for creating employment and guaranteeing environmental sustainability. However, the stochastic nature of wind may affect the integration of power plants into power systems and the availability of generation capacity. In this sense, as in the case of conventional power plants, wind power installations should be able to help maintain power system stability and reliability. To help achieve this objective, a significant number of countries have developed so-called grid interconnection agreements. These are designed to define the technical and behavioral requirements that wind power installations, as well as other power plants, must comply with when seeking connection to the national network. These documents also detail the tasks that should be conducted to certify such installations, so these can be commercially exploited. These certification processes allow countries to assess wind turbine and wind power plant simulation models. These models can then be used to estimate and simulate wind power performance under a variety of scenarios. Within this framework, and with a particular focus on the new Spanish grid code, the present paper addresses the validation process of dynamic wind turbine models followed in three countries—Spain, Germany and South Africa. In these three countries, and as a novel option, it has been proposed that these models form part of the commissioning and certification processes of wind power plants. Full article
(This article belongs to the Special Issue Design, Modeling and Control of Power Electronic Converters for/in Renewable Energy Systems)
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14 pages, 2863 KiB  
Article
Sky Imager-Based Forecast of Solar Irradiance Using Machine Learning
by Anas Al-lahham, Obaidah Theeb, Khaled Elalem, Tariq A. Alshawi and Saleh A. Alshebeili
Electronics 2020, 9(10), 1700; https://doi.org/10.3390/electronics9101700 - 16 Oct 2020
Cited by 32 | Viewed by 5549
Abstract
Ahead-of-time forecasting of the output power of power plants is essential for the stability of the electricity grid and ensuring uninterrupted service. However, forecasting renewable energy sources is difficult due to the chaotic behavior of natural energy sources. This paper presents a new [...] Read more.
Ahead-of-time forecasting of the output power of power plants is essential for the stability of the electricity grid and ensuring uninterrupted service. However, forecasting renewable energy sources is difficult due to the chaotic behavior of natural energy sources. This paper presents a new approach to estimate short-term solar irradiance from sky images. The proposed algorithm extracts features from sky images and use learning-based techniques to estimate the solar irradiance. The performance of proposed machine learning (ML) algorithm is evaluated using two publicly available datasets of sky images. The datasets contain over 350,000 images for an interval of 16 years, from 2004 to 2020, with the corresponding global horizontal irradiance (GHI) of each image as the ground truth. Compared to the state-of-the-art computationally heavy algorithms proposed in the literature, our approach achieves competitive results with much less computational complexity for both nowcasting and forecasting up to 4 h ahead of time. Full article
(This article belongs to the Section Computer Science & Engineering)
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26 pages, 7622 KiB  
Article
Chaotic Particle Swarm Optimisation for Enlarging the Domain of Attraction of Polynomial Nonlinear Systems
by Faiçal Hamidi, Messaoud Aloui, Houssem Jerbi, Mourad Kchaou, Rabeh Abbassi, Dumitru Popescu, Sondess Ben Aoun and Catalin Dimon
Electronics 2020, 9(10), 1704; https://doi.org/10.3390/electronics9101704 - 16 Oct 2020
Cited by 13 | Viewed by 2669
Abstract
A novel technique for estimating the asymptotic stability region of nonlinear autonomous polynomial systems is established. The key idea consists of examining the optimal Lyapunov function (LF) level set that is fully included in a region satisfying the negative definiteness of its time [...] Read more.
A novel technique for estimating the asymptotic stability region of nonlinear autonomous polynomial systems is established. The key idea consists of examining the optimal Lyapunov function (LF) level set that is fully included in a region satisfying the negative definiteness of its time derivative. The minor bound of the biggest achievable region, denoted as Largest Estimation Domain of Attraction (LEDA), can be calculated through a Generalised Eigenvalue Problem (GEVP) as a quasi-convex Linear Inequality Matrix (LMI) optimising approach. An iterative procedure is developed to attain the optimal volume or attraction region. Furthermore, a Chaotic Particular Swarm Optimisation (CPSO) efficient technique is suggested to compute the LF coefficients. The implementation of the established scheme was performed using the Matlab software environment. The synthesised methodology is evaluated throughout several benchmark examples and assessed with other results of peer technique in the literature. Full article
(This article belongs to the Special Issue Control of Nonlinear Systems and Industrial Processes)
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26 pages, 2545 KiB  
Article
Smart Sensing: An Info-Structural Model of Cognition for Non-Interacting Agents
by Gerardo Iovane, Iana Fominska, Riccardo Emanuele Landi and Francesco Terrone
Electronics 2020, 9(10), 1692; https://doi.org/10.3390/electronics9101692 - 15 Oct 2020
Cited by 4 | Viewed by 3901
Abstract
This study explores an info-structural model of cognition for non-interacting agents affected by human sensation, perception, emotion, and affection. We do not analyze the neuroscientific or psychological debate concerning the human mind working, but we underline the importance of modeling the above cognitive [...] Read more.
This study explores an info-structural model of cognition for non-interacting agents affected by human sensation, perception, emotion, and affection. We do not analyze the neuroscientific or psychological debate concerning the human mind working, but we underline the importance of modeling the above cognitive levels when designing artificial intelligence agents. Our aim was to start a reflection on the computational reproduction of intelligence, providing a methodological approach through which the aforementioned human factors in autonomous systems are enhanced. The presented model must be intended as part of a larger one, which also includes concepts of attention, awareness, and consciousness. Experiments have been performed by providing visual stimuli to the proposed model, coupling the emotion cognitive level with a supervised learner to produce artificial emotional activity. For this purpose, performances with Random Forest and XGBoost have been compared and, with the latter algorithm, 85% accuracy and 92% coherency over predefined emotional episodes have been achieved. The model has also been tested on emotional episodes that are different from those related to the training phase, and a decrease in accuracy and coherency has been observed. Furthermore, by decreasing the weight related to the emotion cognitive instances, the model reaches the same performances recorded during the evaluation phase. In general, the framework achieves a first emotional generalization responsiveness of 94% and presents an approximately constant relative frequency related to the agent’s displayed emotions. Full article
(This article belongs to the Section Artificial Intelligence)
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18 pages, 3171 KiB  
Article
Classification of Essential Tremor and Parkinson’s Tremor Based on a Low-Power Wearable Device
by Patrick Locatelli, Dario Alimonti, Gianluca Traversi and Valerio Re
Electronics 2020, 9(10), 1695; https://doi.org/10.3390/electronics9101695 - 15 Oct 2020
Cited by 26 | Viewed by 4888
Abstract
Among movement disorders, essential tremor is by far the most common, as much as eight times more prevalent than Parkinson’s disease. Although these two conditions differ in their presentation and course, clinicians do not always recognize them, leading to common misdiagnoses. Proper and [...] Read more.
Among movement disorders, essential tremor is by far the most common, as much as eight times more prevalent than Parkinson’s disease. Although these two conditions differ in their presentation and course, clinicians do not always recognize them, leading to common misdiagnoses. Proper and early diagnosis is important for receiving the right treatment and support. In this paper, the development of a portable and reliable tremor classification system based on a wearable device, enabling clinicians to differentiate between essential tremor and Parkinson’s disease-associated one, is reported. Inertial data were collected from subjects with a well-established diagnosis of tremor, and analyzed to extract different sets of relevant spectral features. Supervised learning methods were then applied to build several classification models, among which the best ones achieved an average accuracy above 90%. Results encourage the use of wearable technology as effective and affordable tools to support clinicians. Full article
(This article belongs to the Section Bioelectronics)
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15 pages, 3849 KiB  
Article
Assessment of Intuitiveness and Comfort of Wearable Haptic Feedback Strategies for Assisting Level and Stair Walking
by Ilaria Cesini, Giacomo Spigler, Sahana Prasanna, Jessica D’Abbraccio, Daniela De Luca, Filippo Dell’Agnello, Simona Crea, Nicola Vitiello, Alberto Mazzoni and Calogero Maria Oddo
Electronics 2020, 9(10), 1676; https://doi.org/10.3390/electronics9101676 - 14 Oct 2020
Cited by 11 | Viewed by 4623
Abstract
Nowadays, lower-limb prostheses are reaching real-world usability especially on ground-level walking. However, some key tasks such as stair walking are still quite demanding. Providing haptic feedback about the foot placement on the steps might reduce the cognitive load of the task, compensating for [...] Read more.
Nowadays, lower-limb prostheses are reaching real-world usability especially on ground-level walking. However, some key tasks such as stair walking are still quite demanding. Providing haptic feedback about the foot placement on the steps might reduce the cognitive load of the task, compensating for increased dependency on vision and lessen the risk of falling. Experiments on intact subjects can be useful to define the feedback strategies prior to clinical trials, but effective methods to assess the efficacy of the strategies are few and usually rely on the emulation of the disability condition. The present study reports on the design and testing of a wearable haptic feedback system in a protocol involving intact subjects to assess candidate strategies to be adopted in clinical trials. The system integrated a sensorized insole wirelessly connected to a textile waist belt equipped with three vibrating motors. Three stimulation strategies for mapping the insole pressure data to vibrotactile feedback were implemented and compared in terms of intuitiveness and comfort perceived during level and stair walking. The strategies were ranked using a relative rating approach, which highlighted the differences between them and suggested guidelines for their improvement. The feedback evaluation procedure proposed could facilitate the selection and improvement of haptic feedback strategies prior to clinical testing. Full article
(This article belongs to the Special Issue Wearable Electronics for Assessing Human Motor (dis)Abilities)
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24 pages, 2218 KiB  
Article
Blockchain in Intelligent Transportation Systems
by Dragoş Cocîrlea, Ciprian Dobre, Liviu-Adrian Hîrţan and Raluca Purnichescu-Purtan
Electronics 2020, 9(10), 1682; https://doi.org/10.3390/electronics9101682 - 14 Oct 2020
Cited by 17 | Viewed by 4214
Abstract
Blockchain is an emerging technology that has shaken the financial sector, and which is already perceived as having an impact. A blockchain is a network of many interconnected nodes, both trustworthy and malicious, which can reach a consensus and generate valid data. The [...] Read more.
Blockchain is an emerging technology that has shaken the financial sector, and which is already perceived as having an impact. A blockchain is a network of many interconnected nodes, both trustworthy and malicious, which can reach a consensus and generate valid data. The resulting information is packed into a block and permanently saved on the network in a tamper-proof way. In this paper, we propose an adaptation of blockchain for securely storing data in a vehicular-based network. Our approach can work for storing data such as traffic events and user reputation. The proposed solution has two interconnected components: the Intelligent Transportation System (ITS) blockchain and the reputation system. The paper presents synthetic tests which validate the use cases of the solution: users reporting speeds and alerts behind which we see a fair reputation system penalising the (wrong/false) users. Full article
(This article belongs to the Section Networks)
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16 pages, 519 KiB  
Article
Utilising Deep Learning Techniques for Effective Zero-Day Attack Detection
by Hanan Hindy, Robert Atkinson, Christos Tachtatzis, Jean-Noël Colin, Ethan Bayne and Xavier Bellekens
Electronics 2020, 9(10), 1684; https://doi.org/10.3390/electronics9101684 - 14 Oct 2020
Cited by 142 | Viewed by 14716
Abstract
Machine Learning (ML) and Deep Learning (DL) have been used for building Intrusion Detection Systems (IDS). The increase in both the number and sheer variety of new cyber-attacks poses a tremendous challenge for IDS solutions that rely on a database of historical attack [...] Read more.
Machine Learning (ML) and Deep Learning (DL) have been used for building Intrusion Detection Systems (IDS). The increase in both the number and sheer variety of new cyber-attacks poses a tremendous challenge for IDS solutions that rely on a database of historical attack signatures. Therefore, the industrial pull for robust IDSs that are capable of flagging zero-day attacks is growing. Current outlier-based zero-day detection research suffers from high false-negative rates, thus limiting their practical use and performance. This paper proposes an autoencoder implementation for detecting zero-day attacks. The aim is to build an IDS model with high recall while keeping the miss rate (false-negatives) to an acceptable minimum. Two well-known IDS datasets are used for evaluation—CICIDS2017 and NSL-KDD. In order to demonstrate the efficacy of our model, we compare its results against a One-Class Support Vector Machine (SVM). The manuscript highlights the performance of a One-Class SVM when zero-day attacks are distinctive from normal behaviour. The proposed model benefits greatly from autoencoders encoding-decoding capabilities. The results show that autoencoders are well-suited at detecting complex zero-day attacks. The results demonstrate a zero-day detection accuracy of 89–99% for the NSL-KDD dataset and 75–98% for the CICIDS2017 dataset. Finally, the paper outlines the observed trade-off between recall and fallout. Full article
(This article belongs to the Special Issue Advanced Cybersecurity Services Design)
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30 pages, 11651 KiB  
Article
10 Clock-Periods Pipelined Implementation of AES-128 Encryption-Decryption Algorithm up to 28 Gbit/s Real Throughput by Xilinx Zynq UltraScale+ MPSoC ZCU102 Platform
by Paolo Visconti, Stefano Capoccia, Eugenio Venere, Ramiro Velázquez and Roberto de Fazio
Electronics 2020, 9(10), 1665; https://doi.org/10.3390/electronics9101665 - 13 Oct 2020
Cited by 12 | Viewed by 8503
Abstract
The security of communication and computer systems is an increasingly important issue, nowadays pervading all areas of human activity (e.g., credit cards, website encryption, medical data, etc.). Furthermore, the development of high-speed and light-weight implementations of the encryption algorithms is fundamental to improve [...] Read more.
The security of communication and computer systems is an increasingly important issue, nowadays pervading all areas of human activity (e.g., credit cards, website encryption, medical data, etc.). Furthermore, the development of high-speed and light-weight implementations of the encryption algorithms is fundamental to improve and widespread their application in low-cost, low-power and portable systems. In this scientific article, a high-speed implementation of the AES-128 algorithm is reported, developed for a short-range and high-frequency communication system, called Wireless Connector; a Xilinx ZCU102 Field Programmable Gate Array (FPGA) platform represents the core of this communication system since manages all the base-band operations, including the encryption/decryption of the data packets. Specifically, a pipelined implementation of the Advanced Encryption Standard (AES) algorithm has been developed, allowing simultaneous processing of distinct rounds on multiple successive plaintext packets for each clock period and thus obtaining higher data throughput. The proposed encryption system supports 220 MHz maximum operating frequency, ensuring encryption and decryption times both equal to only 10 clock periods. Thanks to the pipelined approach and optimized solutions for the Substitute Bytes operation, the proposed implementation can process and provide the encrypted packets each clock period, thus obtaining a maximum data throughput higher than 28 Gbit/s. Also, the simulation results demonstrate that the proposed architecture is very efficient in using hardware resources, requiring only 1631 Configurable Logic Blocks (CLBs) for the encryption block and 3464 CLBs for the decryption one. Full article
(This article belongs to the Special Issue Emerging Applications of Recent FPGA Architectures)
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17 pages, 1156 KiB  
Article
Lateral-Acceleration-Based Vehicle-Models-Blending for Automated Driving Controllers
by Jose A. Matute-Peaspan, Mauricio Marcano, Sergio Diaz, Asier Zubizarreta and Joshue Perez
Electronics 2020, 9(10), 1674; https://doi.org/10.3390/electronics9101674 - 13 Oct 2020
Cited by 8 | Viewed by 3577
Abstract
Model-based trajectory tracking has become a widely used technique for automated driving system applications. A critical design decision is the proper selection of a vehicle model that achieves the best trade-off between real-time capability and robustness. Blending different types of vehicle models is [...] Read more.
Model-based trajectory tracking has become a widely used technique for automated driving system applications. A critical design decision is the proper selection of a vehicle model that achieves the best trade-off between real-time capability and robustness. Blending different types of vehicle models is a recent practice to increase the operating range of model-based trajectory tracking control applications. However, current approaches focus on the use of longitudinal speed as the blending parameter, with a formal procedure to tune and select its parameters still lacking. This work presents a novel approach based on lateral accelerations, along with a formal procedure and criteria to tune and select blending parameters, for its use on model-based predictive controllers for autonomous driving. An electric passenger bus traveling at different speeds over urban routes is proposed as a case study. Results demonstrate that the lateral acceleration, which is proportional to the lateral forces that differentiate kinematic and dynamic models, is a more appropriate model-switching enabler than the currently used longitudinal velocity. Moreover, the advanced procedure to define blending parameters is shown to be effective. Finally, a smooth blending method offers better tracking results versus sudden model switching ones and non-blending techniques. Full article
(This article belongs to the Special Issue Autonomous Vehicles Technology)
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16 pages, 5494 KiB  
Article
Integrating Driving Hardware-in-the-Loop Simulator with Large-Scale VANET Simulator for Evaluation of Cooperative Eco-Driving System
by Geonil Lee, Seongmin Ha and Jae-il Jung
Electronics 2020, 9(10), 1645; https://doi.org/10.3390/electronics9101645 - 8 Oct 2020
Cited by 11 | Viewed by 4143
Abstract
Recent advances in information and communication technology (ICT) have enabled interaction and cooperation between components of the transportation system, and cooperative eco-driving systems that apply ICT to eco-driving systems are receiving significant attention. A cooperative eco-driving system is a complex system that requires [...] Read more.
Recent advances in information and communication technology (ICT) have enabled interaction and cooperation between components of the transportation system, and cooperative eco-driving systems that apply ICT to eco-driving systems are receiving significant attention. A cooperative eco-driving system is a complex system that requires consideration of the electronic control unit (ECU) and vehicle-to-everything (V2X) communication. To evaluate these complex systems, it is needed to integrate simulators with expertise. Therefore, this study presents an integrated driving hardware-in-the-loop (IDHIL) simulator for the testing and evaluation of cooperative eco-driving systems. The IDHIL simulator is implemented by integrating the driving hardware-in-the-loop simulator and a vehicular ad hoc network simulator to develop and evaluate a hybrid control unit and cooperative eco-driving application for the connected hybrid electric vehicle (CHEV). A cooperative eco-driving speed guidance application is utilized to demonstrate the use of our simulator. The results of the evaluation show the improved fuel efficiency of the CHEV through a calculation of the optimal speed profile and the optimal distribution of power based on V2X communication. Finally, this paper concludes with a description of future directions for the testing and evaluation of cooperative eco-driving systems. Full article
(This article belongs to the Special Issue Autonomous Vehicles Technology)
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24 pages, 8104 KiB  
Article
HIL-Assessed Fast and Accurate Single-Phase Power Calculation Algorithm for Voltage Source Inverters Supplying to High Total Demand Distortion Nonlinear Loads
by Jorge El Mariachet, Yajuan Guan, Jose Matas, Helena Martín, Mingshen Li and Josep M. Guerrero
Electronics 2020, 9(10), 1643; https://doi.org/10.3390/electronics9101643 - 7 Oct 2020
Cited by 10 | Viewed by 3963
Abstract
The dynamic performance of the local control of single-phase voltage source inverters (VSIs) can be degraded when supplying to nonlinear loads (NLLs) in microgrids. When this control is based on the droop principles, a proper calculation of the active and reactive averaged powers [...] Read more.
The dynamic performance of the local control of single-phase voltage source inverters (VSIs) can be degraded when supplying to nonlinear loads (NLLs) in microgrids. When this control is based on the droop principles, a proper calculation of the active and reactive averaged powers (P–Q) is essential for a proficient dynamic response against abrupt NLL changes. In this work, a VSI supplying to an NLL was studied, focusing the attention on the P–Q calculation stage. This stage first generated the direct and in-quadrature signals from the measured load current through a second-order generalized integrator (SOGI). Then, the instantaneous power quantities were obtained by multiplying each filtered current by the output voltage, and filtered later by utilizing a SOGI to acquire the averaged P–Q parameters. The proposed algorithm was compared with previous proposals, while keeping the active power steady-state ripple constant, which resulted in a faster calculation of the averaged active power. In this case, the steady-state averaged reactive power presented less ripple than the best proposal to which it was compared. When reducing the velocity of the proposed algorithm for the active power, it also showed a reduction in its steady-state ripple. Simulations, hardware-in-the-loop, and experimental tests were carried out to verify the effectiveness of the proposal. Full article
(This article belongs to the Special Issue Hardware in the Loop for Electrical Systems: Techniques, Algorithm and Circuits)
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14 pages, 1819 KiB  
Article
A Statistical Approach for the Assessment of Muscle Activation Patterns during Gait in Parkinson’s Disease
by Giulia Pacini Panebianco, Davide Ferrazzoli, Giuseppe Frazzitta, Margherita Fonsato, Maria Cristina Bisi, Silvia Fantozzi and Rita Stagni
Electronics 2020, 9(10), 1641; https://doi.org/10.3390/electronics9101641 - 5 Oct 2020
Cited by 7 | Viewed by 3986
Abstract
Recently, the statistical analysis of muscle activation patterns highlighted that not only one, but several activation patterns can be identified in the gait of healthy adults, with different occurrence. Although its potential, the application of this approach in pathological populations is still limited [...] Read more.
Recently, the statistical analysis of muscle activation patterns highlighted that not only one, but several activation patterns can be identified in the gait of healthy adults, with different occurrence. Although its potential, the application of this approach in pathological populations is still limited and specific implementation issues need to be addressed. This study aims at applying a statistical approach to analyze muscle activation patterns of gait in Parkinson’s Disease, integrating gait symmetry and co-activation. Surface electromyographic signal of tibialis anterior and gastrocnemius medialis were recorded during a 6-min walking test in 20 patients. Symmetry between right and left stride time series was verified, different activation patterns identified, and their occurrence (number and timing) quantified, as well as the co-activation of antagonist muscles. Gastrocnemius medialis presented five activation patterns (mean occurrence ranging from 2% to 43%) showing, with respect to healthy adults, the presence of a first shorted and delayed activation (between flat foot contact and push off, and in the final swing) and highlighting a new second region of anticipated activation (during early/mid swing). Tibialis anterior presented five activation patterns (mean occurrence ranging from 3% to 40%) highlighting absent or delayed activity at the beginning of the gait cycle, and generally shorter and anticipated activations during the swing phase with respect to healthy adults. Three regions of co-contraction were identified: from heel strike to mid-stance, from the pre- to initial swing, and during late swing. This study provided a novel insight in the analysis of muscle activation patterns in Parkinson’s Disease patients with respect to the literature, where unique, at times conflicting, average patterns were reported. The proposed integrated methodology is meant to be generalized for the analysis of muscle activation patterns in pathologic subjects. Full article
(This article belongs to the Special Issue Recent Advances in Motion Analysis)
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16 pages, 4225 KiB  
Article
CED-Net: Crops and Weeds Segmentation for Smart Farming Using a Small Cascaded Encoder-Decoder Architecture
by Abbas Khan, Talha Ilyas, Muhammad Umraiz, Zubaer Ibna Mannan and Hyongsuk Kim
Electronics 2020, 9(10), 1602; https://doi.org/10.3390/electronics9101602 - 1 Oct 2020
Cited by 84 | Viewed by 6782
Abstract
Convolutional neural networks (CNNs) have achieved state-of-the-art performance in numerous aspects of human life and the agricultural sector is no exception. One of the main objectives of deep learning for smart farming is to identify the precise location of weeds and crops on [...] Read more.
Convolutional neural networks (CNNs) have achieved state-of-the-art performance in numerous aspects of human life and the agricultural sector is no exception. One of the main objectives of deep learning for smart farming is to identify the precise location of weeds and crops on farmland. In this paper, we propose a semantic segmentation method based on a cascaded encoder-decoder network, namely CED-Net, to differentiate weeds from crops. The existing architectures for weeds and crops segmentation are quite deep, with millions of parameters that require longer training time. To overcome such limitations, we propose an idea of training small networks in cascade to obtain coarse-to-fine predictions, which are then combined to produce the final results. Evaluation of the proposed network and comparison with other state-of-the-art networks are conducted using four publicly available datasets: rice seeding and weed dataset, BoniRob dataset, carrot crop vs. weed dataset, and a paddy–millet dataset. The experimental results and their comparisons proclaim that the proposed network outperforms state-of-the-art architectures, such as U-Net, SegNet, FCN-8s, and DeepLabv3, over intersection over union (IoU), F1-score, sensitivity, true detection rate, and average precision comparison metrics by utilizing only (1/5.74 × U-Net), (1/5.77 × SegNet), (1/3.04 × FCN-8s), and (1/3.24 × DeepLabv3) fractions of total parameters. Full article
(This article belongs to the Special Issue Deep Neural Networks and Their Applications, Volume II)
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13 pages, 2251 KiB  
Article
N-Type Charge Carrier Transport Properties of BDOPV-Benzothiadiazole-Based Semiconducting Polymers
by Siyu Wang, Sultan Otep, Joost Kimpel, Takehiko Mori and Tsuyoshi Michinobu
Electronics 2020, 9(10), 1604; https://doi.org/10.3390/electronics9101604 - 1 Oct 2020
Cited by 1 | Viewed by 3365
Abstract
High-performance n-type organic semiconducting polymers are key components of next-generation organic electronics. Here, we designed and synthesized two electron deficient organic polymers composed of benzodifurandione-based oligo (p-phenylenevinylene) (BDOPV) and benzothiadiazole by Stille coupling polycondensation. BDOPV-benzothiadiazole-based copolymer (PBDOPV-BTT) possesses a D-A1 [...] Read more.
High-performance n-type organic semiconducting polymers are key components of next-generation organic electronics. Here, we designed and synthesized two electron deficient organic polymers composed of benzodifurandione-based oligo (p-phenylenevinylene) (BDOPV) and benzothiadiazole by Stille coupling polycondensation. BDOPV-benzothiadiazole-based copolymer (PBDOPV-BTT) possesses a D-A1-D-A2 type backbone with intramolecular charge–transfer interactions, while PBDOPV-BTTz is an all-acceptor polymer. The former has a higher molecular weight (Mn) of 109.7 kg∙mol−1 than the latter (Mn = 20.2 kg∙mol−1). The structural difference of these polymers was confirmed by the optical absorption spectra. PBDOPV-BTT showed a more bathochromically shifted absorption spectrum than PBDOPV-BTTz. The longer wavelength absorption of PBDOPV-BTT was due to the intramolecular charge transfer. Therefore, PBDOPV-BTT had a narrower band gap than PBDOPV-BTTz. However, this feature was not reflected by the lowest unoccupied molecular orbital (LUMO) levels. Both polymers displayed almost the same LUMO level of −3.8 eV. Accuracy of this observation was cross-verified by density functional theory (DFT) calculations. The electron-transporting properties were investigated by thin film transistors. PBDOPV-BTT showed an electron mobility (μe) of 1.02 × 10−2 cm2 V−1 s−1 under the optimized annealing conditions. PBDOPV-BTTz exhibited poorer transistor performances with the optimized μe of 9.54 × 10−6 cm2 V−1 s−1. Finally, the grazing-incidence wide angle X-ray scattering (GIWAXS) measurements of both polymer films revealed the higher crystallinity of PBDOPV-BTT with the edge-on orientation. Full article
(This article belongs to the Section Electronic Materials, Devices and Applications)
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11 pages, 5184 KiB  
Article
Design of a Ka-Band U-Shaped Bandpass Filter with 20-GHz Bandwidth in 0.13-μm BiCMOS Technology
by Kai Men, Hang Liu and Kiat Seng Yeo
Electronics 2020, 9(10), 1608; https://doi.org/10.3390/electronics9101608 - 1 Oct 2020
Cited by 4 | Viewed by 3071
Abstract
In this work, the design of a novel Ka-band miniaturized bandpass filter with broad bandwidth is demonstrated by using inversely coupled U-shaped transmission lines. In the proposed filter, two transmission zeros can be generated within a cascaded U-shaped structure and it can also [...] Read more.
In this work, the design of a novel Ka-band miniaturized bandpass filter with broad bandwidth is demonstrated by using inversely coupled U-shaped transmission lines. In the proposed filter, two transmission zeros can be generated within a cascaded U-shaped structure and it can also be proven that, by inversely coupling two stacked U-shaped transmission lines, the notch frequency at the upper stopband can be shifted to a lower frequency, which results in a smaller chip size. The key parameters affecting the performance of the proposed filter are investigated in detail with the effective lumped-element circuit illustrated. Fabricated in a 0.13-μm SiGe BiCMOS process, the proposed filter achieves an insertion loss of 3.6 dB at a frequency of 28.75 GHz and the measured bandwidth is from 20.75 GHz to 41 GHz. The return loss is better than −10 dB from 20.5 GHz to 39 GHz. The lower transmission zero is located at 11.75 GHz with a suppression of 54 dB while the upper transmission zero is around 67 GHz with an attenuation of 34.6 dB. The measurement agrees very well with the simulation results and the overall chip size of the proposed filter is 176 × 269 μm2. Full article
(This article belongs to the Special Issue Millimeter-Wave Integrated Circuits and Systems for 5G Applications)
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14 pages, 1762 KiB  
Article
Blockchain Based Smart Contracts for Internet of Medical Things in e-Healthcare
by Ashutosh Sharma, Sarishma, Ravi Tomar, Naveen Chilamkurti and Byung-Gyu Kim
Electronics 2020, 9(10), 1609; https://doi.org/10.3390/electronics9101609 - 1 Oct 2020
Cited by 128 | Viewed by 8960
Abstract
The concept of Blockchain has penetrated a wide range of scientific areas, and its use is considered to rise exponentially in the near future. Executing short scripts of predefined code called smart contracts on Blockchain can eliminate the need of intermediaries and can [...] Read more.
The concept of Blockchain has penetrated a wide range of scientific areas, and its use is considered to rise exponentially in the near future. Executing short scripts of predefined code called smart contracts on Blockchain can eliminate the need of intermediaries and can also raise the multitude of execution of contracts. In this paper, we discuss the concept of Blockchain along with smart contracts and discuss their applicability in the Internet of Medical Things (IoMT) in the e-healthcare domain. The paper analyses the dimensions that decentralization and the use of smart contracts will take the IoMT in e-healthcare, proposes a novel architecture, and also outlines the advantages, challenges, and future trends related to the integration of all three. The proposed architecture shows its effectiveness with average packet delivery ratio, average latency, and average energy efficiency performance parameters when compared with traditional approaches. Full article
(This article belongs to the Special Issue Blockchain Based Electronic Healthcare Solution and Security)
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11 pages, 548 KiB  
Article
Compact Rectifier Circuit Design for Harvesting GSM/900 Ambient Energy
by Surajo Muhammad, Jun Jiat Tiang, Sew Kin Wong, Amjad Iqbal, Mohammad Alibakhshikenari and Ernesto Limiti
Electronics 2020, 9(10), 1614; https://doi.org/10.3390/electronics9101614 - 1 Oct 2020
Cited by 42 | Viewed by 5260
Abstract
In this paper, a compact rectifier, capable of harvesting ambient radio frequency (RF) power is proposed. The total size of the rectifier is 45.4 mm × 7.8 mm × 1.6 mm, designed on FR-4 substrate using a single-stage voltage multiplier at 900 MHz. [...] Read more.
In this paper, a compact rectifier, capable of harvesting ambient radio frequency (RF) power is proposed. The total size of the rectifier is 45.4 mm × 7.8 mm × 1.6 mm, designed on FR-4 substrate using a single-stage voltage multiplier at 900 MHz. GSM/900 is among the favorable RF Energy Harvesting (RFEH) energy sources that span over a wide range with minimal path loss and high input power. The proposed RFEH rectifier achieves measured and simulated RF-to-dc (RF to direct current) power conversion efficiency (PCE) of 43.6% and 44.3% for 0 dBm input power, respectively. Additionally, the rectifier attained 3.1 V DC output voltage across 2 kΩ load terminal for 14 dBm and is capable of sensing low input power at −20 dBm. The work presents a compact rectifier to harvest RF energy at 900 MHz, making it a good candidate for low powered wireless communication systems as compares to the other state of the art rectifier. Full article
(This article belongs to the Special Issue Recent Advances in Antenna Design for 5G Heterogeneous Networks)
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10 pages, 432 KiB  
Article
Methodology for Modeling and Comparing Video Codecs: HEVC, EVC, and VVC
by Stefano Battista, Massimo Conti and Simone Orcioni
Electronics 2020, 9(10), 1579; https://doi.org/10.3390/electronics9101579 - 27 Sep 2020
Cited by 11 | Viewed by 4767
Abstract
Online videos are the major source of internet traffic, and are about to become the largest majority. Increasing effort is aimed to developing more efficient video codecs. In order to compare existing and novel video codecs, this paper presents a simple but effective [...] Read more.
Online videos are the major source of internet traffic, and are about to become the largest majority. Increasing effort is aimed to developing more efficient video codecs. In order to compare existing and novel video codecs, this paper presents a simple but effective methodology to model their performance in terms of Rate Distortion (RD). A linear RD model in the dB variables, Peak Signal-to-Noise Ratio (PSNR) and Bitrate (BR), easily allows us to estimate the difference in PSNR or BR between two sets of encoding conditions. Six sequences from the MPEG test set with the same resolution, encoded at different BR and different Quantization Parameters, were used to create the data set to estimate each RD model. Three codecs (HEVC, EVC, and VVC) were compared with this methodology, after estimating their models. Fitting properties of each model and a performance comparison between the models are finally shown and discussed. Full article
(This article belongs to the Special Issue Multimedia Systems and Signal Processing)
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16 pages, 4676 KiB  
Article
Four-Level Hysteresis-Based DTC for Torque Capability Improvement of IPMSM Fed by Three-Level NPC Inverter
by Samer Saleh Hakami and Kyo-Beum Lee
Electronics 2020, 9(10), 1558; https://doi.org/10.3390/electronics9101558 - 23 Sep 2020
Cited by 21 | Viewed by 3444
Abstract
Direct torque control (DTC) is considered one of the simplest and fastest control strategies used in motor drives. However, it produces large torque and flux ripples. Replacing the conventional two-level hysteresis torque controller (HTC) with a four-level HTC for a three-level neutral-point clamped [...] Read more.
Direct torque control (DTC) is considered one of the simplest and fastest control strategies used in motor drives. However, it produces large torque and flux ripples. Replacing the conventional two-level hysteresis torque controller (HTC) with a four-level HTC for a three-level neutral-point clamped (NPC) inverter can reduce the torque and flux ripples in interior permanent magnet synchronous motor (IPMSM) drives. However, the torque will not be controlled properly within the upper HTC bands when driving the IPMSM in the medium and high-speed regions. This problem causes the stator current to drop, resulting in poor torque control. To resolve this problem, a simple algorithm based on a torque error average calculation is proposed. Firstly, the proposed algorithm reads the information of the calculated torque and the corresponding torque reference to calculate the torque error. Secondly, the average value of torque error is calculated instantaneously as the reference torque changes. Finally, the average value of the torque error is used to indicate the operation of the proposed algorithm without the need for motor speed information. By using the proposed algorithm, the torque can be controlled well in all speed regions, and thus, a better stator current waveform can be obtained. Simulation and experimental results validate the effectiveness of the proposed method. Full article
(This article belongs to the Special Issue State-of-the-art Power Electronics in Korea)
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20 pages, 2484 KiB  
Communication
Novel Fault Identification for Electromechanical Systems via Spectral Technique and Electrical Data Processing
by Tomasz Ciszewski, Len Gelman and Andrew Ball
Electronics 2020, 9(10), 1560; https://doi.org/10.3390/electronics9101560 - 23 Sep 2020
Cited by 8 | Viewed by 3219
Abstract
It is proposed, developed, investigated, and validated by experiments and modelling for the first time in worldwide terms new data processing technologies, higher order spectral multiple correlation technologies for fault identification for electromechanical systems via electrical data processing. Investigation of the higher order [...] Read more.
It is proposed, developed, investigated, and validated by experiments and modelling for the first time in worldwide terms new data processing technologies, higher order spectral multiple correlation technologies for fault identification for electromechanical systems via electrical data processing. Investigation of the higher order spectral triple correlation technology via modelling has shown that the proposed data processing technology effectively detects component faults. The higher order spectral triple correlation technology successfully applied for rolling bearing fault identification. Experimental investigation of the technology has shown, that the technology effectively identifies rolling bearing fault by electrical data processing at very early stage of fault development. Novel technology comparisons via modelling and experiments of the proposed higher order spectral triple correlation technology and the higher order spectra technology show the higher fault identification effectiveness of the proposed technology over the bicoherence technology. Full article
(This article belongs to the Special Issue Fault Identification and Prognosis for Electromechanical Systems)
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16 pages, 3578 KiB  
Article
Defect Detection in Printed Circuit Boards Using You-Only-Look-Once Convolutional Neural Networks
by Venkat Anil Adibhatla, Huan-Chuang Chih, Chi-Chang Hsu, Joseph Cheng, Maysam F. Abbod and Jiann-Shing Shieh
Electronics 2020, 9(9), 1547; https://doi.org/10.3390/electronics9091547 - 22 Sep 2020
Cited by 139 | Viewed by 14751
Abstract
In this study, a deep learning algorithm based on the you-only-look-once (YOLO) approach is proposed for the quality inspection of printed circuit boards (PCBs). The high accuracy and efficiency of deep learning algorithms has resulted in their increased adoption in every field. Similarly, [...] Read more.
In this study, a deep learning algorithm based on the you-only-look-once (YOLO) approach is proposed for the quality inspection of printed circuit boards (PCBs). The high accuracy and efficiency of deep learning algorithms has resulted in their increased adoption in every field. Similarly, accurate detection of defects in PCBs by using deep learning algorithms, such as convolutional neural networks (CNNs), has garnered considerable attention. In the proposed method, highly skilled quality inspection engineers first use an interface to record and label defective PCBs. The data are then used to train a YOLO/CNN model to detect defects in PCBs. In this study, 11,000 images and a network of 24 convolutional layers and 2 fully connected layers were used. The proposed model achieved a defect detection accuracy of 98.79% in PCBs with a batch size of 32. Full article
(This article belongs to the Special Issue Convolutional Neural Networks and Vision Applications)
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19 pages, 23557 KiB  
Article
Development of a Multi-Purpose Autonomous Differential Drive Mobile Robot for Plant Phenotyping and Soil Sensing
by Jawad Iqbal, Rui Xu, Hunter Halloran and Changying Li
Electronics 2020, 9(9), 1550; https://doi.org/10.3390/electronics9091550 - 22 Sep 2020
Cited by 41 | Viewed by 13848
Abstract
To help address the global growing demand for food and fiber, selective breeding programs aim to cultivate crops with higher yields and more resistance to stress. Measuring phenotypic traits needed for breeding programs is usually done manually and is labor-intensive, subjective, and lacks [...] Read more.
To help address the global growing demand for food and fiber, selective breeding programs aim to cultivate crops with higher yields and more resistance to stress. Measuring phenotypic traits needed for breeding programs is usually done manually and is labor-intensive, subjective, and lacks adequate temporal resolution. This paper presents a Multipurpose Autonomous Robot of Intelligent Agriculture (MARIA), an open source differential drive robot that is able to navigate autonomously indoors and outdoors while conducting plant morphological trait phenotyping and soil sensing. For the design of the rover, a drive system was developed using the Robot Operating System (ROS), which allows for autonomous navigation using Global Navigation Satellite Systems (GNSS). For phenotyping, the robot was fitted with an actuated LiDAR unit and a depth camera that can estimate morphological traits of plants such as volume and height. A three degree-of-freedom manipulator mounted on the mobile platform was designed using Dynamixel servos that can perform soil sensing and sampling using off-the-shelf and 3D printed components. MARIA was able to navigate both indoors and outdoors with an RMSE of 0.0156 m and 0.2692 m, respectively. Additionally, the onboard actuated LiDAR sensor was able to estimate plant volume and height with an average error of 1.76% and 3.2%, respectively. The manipulator performance tests on soil sensing was also satisfactory. This paper presents a design for a differential drive mobile robot built from off-the-shelf components that makes it replicable and available for implementation by other researchers. The validation of this system suggests that it may be a valuable solution to address the phenotyping bottleneck by providing a system capable of navigating through crop rows or a greenhouse while conducting phenotyping and soil measurements. Full article
(This article belongs to the Special Issue Modeling, Control, and Applications of Field Robotics)
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24 pages, 3816 KiB  
Article
Managing Wireless Communications for Emergency Situations in Urban Environments through Cyber-Physical Systems and 5G Technologies
by Borja Bordel Sánchez, Ramón Alcarria and Tomás Robles
Electronics 2020, 9(9), 1524; https://doi.org/10.3390/electronics9091524 - 17 Sep 2020
Cited by 8 | Viewed by 3888
Abstract
Currently, urban environments are the basic human habitat. Large and complex infrastructures coordinate urban life and make it possible in high-density scenarios. In this context, one basic infrastructure to be considered is communication networks. Nowadays, even emergency response teams (ERT) are dependent on [...] Read more.
Currently, urban environments are the basic human habitat. Large and complex infrastructures coordinate urban life and make it possible in high-density scenarios. In this context, one basic infrastructure to be considered is communication networks. Nowadays, even emergency response teams (ERT) are dependent on those deployments. However, emergencies may cause important damage in those communication infrastructures and, then, a critical discoordination among ERT might appear, greatly affecting the ERT efficiency and response capacity. Different architectures to address this situation have been recently proposed, but none of them are able to dynamically adapt to highly variable situations such as emergency crisis. Therefore, in this paper, a new approach is proposed for ad hoc emergency wireless communications in urban environments based on 5G technologies and Cyber-Physical Systems (CPS). The proposed architecture consists of three layers, where different feedback control loops are defined and linked following the CPS paradigm. At physical level, the spectrum usage is monitored through CPS control loops, analyzing if power signals present a good quality. At network level, 5G virtualization technologies are employed to manage in a dynamic way the network configuration and user management. Finally, at service level, the global situation is analyzed to decide about what services from a catalogue, and according to their priority, can be deployed, including the amount of assigned resources. To evaluate the performance of the proposed solution, an experimental validation based on simulation techniques is also described. Full article
(This article belongs to the Special Issue Emerging Advances for Cyber-Physical Systems)
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21 pages, 3602 KiB  
Article
Parallel Classification Pipelines for Skin Cancer Detection Exploiting Hyperspectral Imaging on Hybrid Systems
by Emanuele Torti, Raquel Leon, Marco La Salvia, Giordana Florimbi, Beatriz Martinez-Vega, Himar Fabelo, Samuel Ortega, Gustavo M. Callicó and Francesco Leporati
Electronics 2020, 9(9), 1503; https://doi.org/10.3390/electronics9091503 - 13 Sep 2020
Cited by 22 | Viewed by 6041
Abstract
The early detection of skin cancer is of crucial importance to plan an effective therapy to treat the lesion. In routine medical practice, the diagnosis is based on the visual inspection of the lesion and it relies on the dermatologists’ expertise. After a [...] Read more.
The early detection of skin cancer is of crucial importance to plan an effective therapy to treat the lesion. In routine medical practice, the diagnosis is based on the visual inspection of the lesion and it relies on the dermatologists’ expertise. After a first examination, the dermatologist may require a biopsy to confirm if the lesion is malignant or not. This methodology suffers from false positives and negatives issues, leading to unnecessary surgical procedures. Hyperspectral imaging is gaining relevance in this medical field since it is a non-invasive and non-ionizing technique, capable of providing higher accuracy than traditional imaging methods. Therefore, the development of an automatic classification system based on hyperspectral images could improve the medical practice to distinguish pigmented skin lesions from malignant, benign, and atypical lesions. Additionally, the system can assist general practitioners in first aid care to prevent noncritical lesions from reaching dermatologists, thereby alleviating the workload of medical specialists. In this paper is presented a parallel pipeline for skin cancer detection that exploits hyperspectral imaging. The computational times of the serial processing have been reduced by adopting multicore and many-core technologies, such as OpenMP and CUDA paradigms. Different parallel approaches have been combined, leading to the development of fifteen classification pipeline versions. Experimental results using in-vivo hyperspectral images show that a hybrid parallel approach is capable of classifying an image of 50 × 50 pixels with 125 bands in less than 1 s. Full article
(This article belongs to the Special Issue Hardware Architectures for Real Time Image Processing)
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20 pages, 5608 KiB  
Article
A Computationally Efficient Algorithm for Feedforward Active Noise Control Systems
by Stefano Gaiotto, Antonino Laudani, Gabriele Maria Lozito and Francesco Riganti Fulginei
Electronics 2020, 9(9), 1504; https://doi.org/10.3390/electronics9091504 - 13 Sep 2020
Cited by 3 | Viewed by 3569
Abstract
In this paper, a novel algorithm with high computational efficiency is proposed for the filter adaptation in a feedforward active noise control system. The proposed algorithm Zero Forcing Block Adaptive Filter (ZF-BAF) performs filter adaptation on a block-by-block basis in the frequency domain. [...] Read more.
In this paper, a novel algorithm with high computational efficiency is proposed for the filter adaptation in a feedforward active noise control system. The proposed algorithm Zero Forcing Block Adaptive Filter (ZF-BAF) performs filter adaptation on a block-by-block basis in the frequency domain. Filtering is performed in the time domain on a sample-by-sample basis. Working in the frequency domain permits us to get sub-linear complexity, whereas filtering in the time domain minimizes the latency. Furthermore, computational burden is tunable to meet specific requirements about adaptation speed and processing load. No other parameter tuning according to the working condition is required. Computer simulations, performed in different realistic cases against other high-performing time and frequency-domain algorithms, show that achievable performances are comparable, or even better, with those of the algorithms perfectly tuned for each specific case. Robustness exhibited in the tests suggests that performances are expected to be even better in a wide range of real cases where it is impossible to know a priori how to tune the algorithms. Full article
(This article belongs to the Section Systems & Control Engineering)
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15 pages, 5132 KiB  
Review
A Review on Biomedical MIMO Radars for Vital Sign Detection and Human Localization
by Emanuele Cardillo and Alina Caddemi
Electronics 2020, 9(9), 1497; https://doi.org/10.3390/electronics9091497 - 11 Sep 2020
Cited by 63 | Viewed by 8570
Abstract
This paper reports a thorough overview on the last developments concerning the vital sign detection and the human localization employing the multiple-input-multiple-output (MIMO) technology. The wireless motion and vital sign detection represents an outstanding research area aimed at monitoring the health conditions of [...] Read more.
This paper reports a thorough overview on the last developments concerning the vital sign detection and the human localization employing the multiple-input-multiple-output (MIMO) technology. The wireless motion and vital sign detection represents an outstanding research area aimed at monitoring the health conditions of human subjects and at detecting their presence in different environments with minimal concern. MIMO radars exhibit several interesting advantages over conventional single-input-single-output architectures mainly related to their angle detection capabilities and enhanced signal-to-noise ratio. This paper describes the main features and details the operating principles of MIMO technology. Thereafter, it summarizes the state-of-the-art of the available solutions with the purpose of fueling the research activities on this hot topic. Full article
(This article belongs to the Special Issue RF/Mm-Wave Circuits Design and Applications)
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12 pages, 6477 KiB  
Article
Field-Oriented Driving/Braking Control for Electric Vehicles
by Shang-Ming Liu, Chia-Hung Tu, Chun-Liang Lin and Van-Tsai Liu
Electronics 2020, 9(9), 1484; https://doi.org/10.3390/electronics9091484 - 10 Sep 2020
Cited by 12 | Viewed by 8677
Abstract
Most electric vehicles use regenerative brakes, since this kind of braking system design recycles electromotive force to increase electric power endurance during braking. This research proposes a sensor-free, integrated driving and braking control system that uses a space-vector-pulse-width module to synthesize stator current [...] Read more.
Most electric vehicles use regenerative brakes, since this kind of braking system design recycles electromotive force to increase electric power endurance during braking. This research proposes a sensor-free, integrated driving and braking control system that uses a space-vector-pulse-width module to synthesize stator current by purpose. It calculates the rotor position angle of the motor by detecting variation in the stator current and completes a closed-loop control. When the motor receives a brake command, the controller changes the inverter-switching sequence to generate reverse torque and a magnetic field to complete the driving or braking function using field-oriented control (FOC). This provides a smoother and more accurate motor control than sinusoidal commands with Hall feedback. Compared to the regenerative brake and rheostatic brake, the proposed braking system has a powerful braking torque and shorter reaction time. Comparisons of reaction times for a modified four-wheel electric vehicle equipped with a permanent magnet synchronous motor under neutral-sliding-status, FOC based braking, and short-circuit braking were conducted. Full article
(This article belongs to the Special Issue Battery Chargers and Management for Electric Vehicles)
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17 pages, 8486 KiB  
Article
An Active Power Filter with Energy Storage and Double DC Conversion for Power Surge Compensation
by Marcin Baszynski, Kacper Sowa and Stanislaw Pirog
Electronics 2020, 9(9), 1489; https://doi.org/10.3390/electronics9091489 - 10 Sep 2020
Cited by 5 | Viewed by 4053
Abstract
This paper presents a single-phase power filter with an energy storage bidirectional DC/DC converter, both of which are equipped with separate capacitor-based DC links that provides good transient response and reduce energy storage capacity. The device is dedicated to the compensation of active [...] Read more.
This paper presents a single-phase power filter with an energy storage bidirectional DC/DC converter, both of which are equipped with separate capacitor-based DC links that provides good transient response and reduce energy storage capacity. The device is dedicated to the compensation of active power surges generated by nonlinear loads characterized by intermittent operation, where the operating time of a device in relation to the idle time is relatively short. As a compensated and filtered object, the single-phase spot welding machine with a thyristor current controller was assumed. In the case of such devices, the feeder has to be dimensioned for the peak loads, which increase the cost of installation—due to the fact that the used components have to be oversized. The proposed solution can produce measurable economic benefits by reducing the rated power necessary to energize periodically operating loads and improve the indicators of electrical energy quality. An elaborated control algorithm based on a switchable control structure provides a fast and good transient response. The work contains a comprehensive analysis of storage sizing, confirmed by simulation results performed in the Matlab and Simulink environment. Based on the analyses carried out, the laboratory model of the device was implemented and experimental verification performed. Full article
(This article belongs to the Section Industrial Electronics)
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22 pages, 5168 KiB  
Article
The Use of Time-Frequency Moments as Inputs of LSTM Network for ECG Signal Classification
by Grzegorz Kłosowski, Tomasz Rymarczyk, Dariusz Wójcik, Stanisław Skowron, Tomasz Cieplak and Przemysław Adamkiewicz
Electronics 2020, 9(9), 1452; https://doi.org/10.3390/electronics9091452 - 6 Sep 2020
Cited by 62 | Viewed by 7311
Abstract
This paper refers to the method of using the deep neural long-short-term memory (LSTM) network for the problem of electrocardiogram (ECG) signal classification. ECG signals contain a lot of subtle information analyzed by doctors to determine the type of heart dysfunction. Due to [...] Read more.
This paper refers to the method of using the deep neural long-short-term memory (LSTM) network for the problem of electrocardiogram (ECG) signal classification. ECG signals contain a lot of subtle information analyzed by doctors to determine the type of heart dysfunction. Due to the large number of signal features that are difficult to identify, raw ECG data is usually not suitable for use in machine learning. The article presents how to transform individual ECG time series into spectral images for which two characteristics are determined, which are instantaneous frequency and spectral entropy. Feature extraction consists of converting the ECG signal into a series of spectral images using short-term Fourier transformation. Then the images were converted using Fourier transform again to two signals, which includes instantaneous frequency and spectral entropy. The data set transformed in this way was used to train the LSTM network. During the experiments, the LSTM networks were trained for both raw and spectrally transformed data. Then, the LSTM networks trained in this way were compared with each other. The obtained results prove that the transformation of input signals into images can be an effective method of improving the quality of classifiers based on deep learning. Full article
(This article belongs to the Section Bioelectronics)
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15 pages, 2150 KiB  
Article
Backhaul-Aware Dimensioning and Planning of Millimeter-Wave Small Cell Networks
by Pablo Muñoz, Oscar Adamuz-Hinojosa, Pablo Ameigeiras, Jorge Navarro-Ortiz and Juan J. Ramos-Muñoz
Electronics 2020, 9(9), 1429; https://doi.org/10.3390/electronics9091429 - 2 Sep 2020
Cited by 2 | Viewed by 4100
Abstract
The massive deployment of Small Cells (SCs) is increasingly being adopted by mobile operators to face the exponentially growing traffic demand. Using the millimeter-wave (mmWave) band in the access and backhaul networks will be key to provide the capacity that meets such demand. [...] Read more.
The massive deployment of Small Cells (SCs) is increasingly being adopted by mobile operators to face the exponentially growing traffic demand. Using the millimeter-wave (mmWave) band in the access and backhaul networks will be key to provide the capacity that meets such demand. However, dimensioning and planning have become complex tasks, because the capacity requirements for mmWave links can significantly vary with the SC location. In this work, we address the problem of SC planning considering the backhaul constraints, assuming that a line-of-sight (LOS) between the nodes is required to reliably support the traffic demand. Such a LOS condition reduces the set of potential site locations. Simulation results show that, under certain conditions, the proposed algorithm is effective in finding solutions and strongly efficient in computational cost when compared to exhaustive search approaches. Full article
(This article belongs to the Special Issue Radio Access Network Planning and Management)
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39 pages, 2017 KiB  
Review
Issues, Challenges, and Research Trends in Spectrum Management: A Comprehensive Overview and New Vision for Designing 6G Networks
by Faizan Qamar, Maraj Uddin Ahmed Siddiqui, MHD Nour Hindia, Rosilah Hassan and Quang Ngoc Nguyen
Electronics 2020, 9(9), 1416; https://doi.org/10.3390/electronics9091416 - 1 Sep 2020
Cited by 96 | Viewed by 12631
Abstract
With an extensive growth in user demand for high throughput, large capacity, and low latency, the ongoing deployment of Fifth-Generation (5G) systems is continuously exposing the inherent limitations of the system, as compared with its original premises. Such limitations are encouraging researchers worldwide [...] Read more.
With an extensive growth in user demand for high throughput, large capacity, and low latency, the ongoing deployment of Fifth-Generation (5G) systems is continuously exposing the inherent limitations of the system, as compared with its original premises. Such limitations are encouraging researchers worldwide to focus on next-generation 6G wireless systems, which are expected to address the constraints. To meet the above demands, future radio network architecture should be effectively designed to utilize its maximum radio spectrum capacity. It must simultaneously utilize various new techniques and technologies, such as Carrier Aggregation (CA), Cognitive Radio (CR), and small cell-based Heterogeneous Networks (HetNet), high-spectrum access (mmWave), and Massive Multiple-Input-Multiple-Output (M-MIMO), to achieve the desired results. However, the concurrent operations of these techniques in current 5G cellular networks create several spectrum management issues; thus, a comprehensive overview of these emerging technologies is presented in detail in this study. Then, the problems involved in the concurrent operations of various technologies for the spectrum management of the current 5G network are highlighted. The study aims to provide a detailed review of cooperative communication among all the techniques and potential problems associated with the spectrum management that has been addressed with the possible solutions proposed by the latest researches. Future research challenges are also discussed to highlight the necessary steps that can help achieve the desired objectives for designing 6G wireless networks. Full article
(This article belongs to the Special Issue Toward a New Era of Radio Access Technologies for 5G and Beyond)
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10 pages, 2995 KiB  
Article
Gallium Nitride Normally Off MOSFET Using Dual-Metal-Gate Structure for the Improvement in Current Drivability
by Young Jun Yoon, Jae Sang Lee, Dong-Seok Kim, Jung-Hee Lee and In Man Kang
Electronics 2020, 9(9), 1402; https://doi.org/10.3390/electronics9091402 - 30 Aug 2020
Cited by 11 | Viewed by 7327
Abstract
A gallium nitride (GaN)-based normally off metal–oxide–semiconductor field-effect transistor (MOSFET) using a dual-metal-gate (DMG) structure was proposed and fabricated to improve current drivability. Normally off operation with a high Vth of 2.3 V was obtained using a Cl2/BCl3-based [...] Read more.
A gallium nitride (GaN)-based normally off metal–oxide–semiconductor field-effect transistor (MOSFET) using a dual-metal-gate (DMG) structure was proposed and fabricated to improve current drivability. Normally off operation with a high Vth of 2.3 V was obtained using a Cl2/BCl3-based recess etching process. The DMG structure was employed to improve current characteristics, which can be degraded by recess etching. The ID and gm of a DMG-based device with nickel (Ni)-aluminum (Al) were improved by 42.1% and 30.9%, respectively, in comparison to the performances of a single-metal-gate-based device with Ni because the DMG structure increased electron velocity in the channel region. This demonstrates that the DMG structure with a large work-function difference significantly improves the carrier transport efficiency. GaN-based recessed-gate MOSFETs based on the DMG structure hold promising potentials for high-efficiency power devices. Full article
(This article belongs to the Section Semiconductor Devices)
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19 pages, 8257 KiB  
Article
Control of Single-Phase Electrolytic Capacitor-Less Isolated Converter for DC Low Voltage Residential Networks
by Nelson Santos, J. Fernando Silva and Vasco Soares
Electronics 2020, 9(9), 1401; https://doi.org/10.3390/electronics9091401 - 29 Aug 2020
Cited by 2 | Viewed by 3789
Abstract
In recent years, there has been a desire to improve electricity generation and consumption, to reach sustainability. Technological solutions today allow a rational use of electricity with good overall performance. Traditionally, from production to distribution, electrical energy is AC-supported for compatibility reasons and [...] Read more.
In recent years, there has been a desire to improve electricity generation and consumption, to reach sustainability. Technological solutions today allow a rational use of electricity with good overall performance. Traditionally, from production to distribution, electrical energy is AC-supported for compatibility reasons and easy voltage level transformation. However, nowadays most electric loads need DC power to work properly. A single high-efficiency central AC-DC power converter may be advantageous in eliminating several less efficient AC-DC embedded converters, distributed all over a residential area. This paper presents a new single-phase AC-DC converter using one active bridge (most isolated topologies are based on the dual active bridge concept) and a high-frequency isolation transformer with low-value non-electrolytic capacitors, together with its control system design. The converter can be introduced into future low-voltage DC microgrids for residential buildings, as an alternative to several embedded AC-DC converters. Non-linear control techniques (sliding mode control and the Lyapunov direct method) are employed to guarantee stability in the output DC low voltage with near unity power factor compensation in the AC grid. The designed converter and controllers were simulated using Matlab/Simulink and tested in a lab experimental prototype using digital signal processing (DSP) to evaluate system performance. Full article
(This article belongs to the Special Issue Advances in Power Electronics Technologies for Renewable Energy Systems)
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15 pages, 6732 KiB  
Article
High-Gain Planar Array of Reactively Loaded Antennas for Limited Scan Range Applications
by Ronis Maximidis, Diego Caratelli, Giovanni Toso and A. Bart Smolders
Electronics 2020, 9(9), 1376; https://doi.org/10.3390/electronics9091376 - 25 Aug 2020
Cited by 3 | Viewed by 3973
Abstract
This paper proposes a novel high-gain antenna element that can be used in antenna arrays that only require a limited scan range. Each high-gain antenna element uses a linear sub-array of highly-coupled open-ended waveguides. The active central element of this sub-array is directly [...] Read more.
This paper proposes a novel high-gain antenna element that can be used in antenna arrays that only require a limited scan range. Each high-gain antenna element uses a linear sub-array of highly-coupled open-ended waveguides. The active central element of this sub-array is directly fed, while the remaining passive waveguides are reactively loaded. The loads are implemented by short-circuits positioned at various distances from the radiating aperture. The short-circuit positions control the radiation pattern properties and the scattering parameters of the array. The proposed sub-array antenna element is optimized in the presence of the adjacent elements and provides a high gain and a flat-top main lobe. The horizontal distance between the sub-array centers is large in terms of wavelengths, which leads to limited scanning capabilities in the E-plane. However, along the vertical axis, the element spacing is around 0.6 wavelength at the central frequency that is beneficial to achieve a wider scan range in the H-plane. We show that the sub-array radiation pattern sufficiently filters the grating lobes which appear in the array factor along the E-plane. To demonstrate the performance of the proposed array configuration, an array operating at 28.0 GHz is designed. The designed array supports scan angles up to ±7.5° along the E-plane and ±24.2° along the H-plane Full article
(This article belongs to the Special Issue Antennas and Propagation Aspects for Emerging Wireless Communication Technologies)
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19 pages, 3585 KiB  
Article
Energy Harvesting from Bicycle Vibrations by Means of Tuned Piezoelectric Generators
by Alberto Doria, Edoardo Marconi and Federico Moro
Electronics 2020, 9(9), 1377; https://doi.org/10.3390/electronics9091377 - 25 Aug 2020
Cited by 12 | Viewed by 7475
Abstract
Vibrations of two typical bicycles are measured by means of road tests in bicycle lanes. The analysis of experimental results in terms of power spectral density (PSD) of the acceleration components shows that most of the energy associated to bicycle vibrations is concentrated [...] Read more.
Vibrations of two typical bicycles are measured by means of road tests in bicycle lanes. The analysis of experimental results in terms of power spectral density (PSD) of the acceleration components shows that most of the energy associated to bicycle vibrations is concentrated in a low frequency band (<30 Hz). Since piezoelectric cantilever harvesters achieve the best performance in resonance and the resonant frequency is well above 30 Hz, specific tuning strategies are adopted. A novel mathematical model for simulating the electro-mechanical behaviour of a piezoelectric harvester equipped with an auxiliary oscillator is proposed. Calculated results show the potentialities of this tuning device in terms of generated voltage and stress inside the piezoelectric layer. Prototypes of harvesters equipped with auxiliary oscillators are built and tested in the laboratory obtaining the frequency response function (FRF) of generated voltage. Finally, the average electric power generated by these harvesters (which are assumed to be interfaced to an electronic load by a power management unit based on synchronous rectifying technique) is simulated by using the measured FRFs and PSDs of bicycle vibrations. Full article
(This article belongs to the Special Issue Recent Trends in Multi-Physics Simulation and Testing of New E-Mobility Technologies)
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17 pages, 9047 KiB  
Article
Analysis of the Multi-Steps Package (MSP) for Series-Connected SiC-MOSFETs
by Luciano F. S. Alves, Pierre Lefranc, Pierre-Olivier Jeannin, Benoit Sarrazin and Jean-Christophe Crebier
Electronics 2020, 9(9), 1341; https://doi.org/10.3390/electronics9091341 - 19 Aug 2020
Cited by 8 | Viewed by 3668
Abstract
In this paper, a multi-step packaging (MSP) concept for series-connected SiC-MOSFETs is analyzed. The parasitic capacitance generated by the dielectric isolation of each device in the stack has a significant impact on the dynamic behavior of SiC devices, which impacts the voltage-sharing performances. [...] Read more.
In this paper, a multi-step packaging (MSP) concept for series-connected SiC-MOSFETs is analyzed. The parasitic capacitance generated by the dielectric isolation of each device in the stack has a significant impact on the dynamic behavior of SiC devices, which impacts the voltage-sharing performances. The study performed in this work reveals that the parasitic capacitance network introduced by the classical planar packaging unbalances the voltage across the series-connected SiC-MOSFETs. Therefore, a new drain-source parasitic capacitance network configuration provided by the MSP is proposed in order to improve the voltage balancing across the series-connected devices. The concept is introduced and analyzed thanks to equivalent models and time domain simulations. To verify the analysis, the voltage sharing between four series-connected 1.2 kV SiC MOSFETs is tested in a double pulse test setup. The experimental results confirm that the MSP has a better performance than the classical one in terms of voltage sharing. Furthermore, the proposed investigation shows that the MSP increases the middle point dv/dt of the switching cell. Sensitive analysis and thermal management considerations are also discussed in order to clarify the MSP limitations and indicate the ways to optimize the MSP from a thermal point of view. Full article
(This article belongs to the Special Issue Multilevel Converters)
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17 pages, 17926 KiB  
Article
Luenberger Position Observer Based on Deadbeat-Current Predictive Control for Sensorless PMSM
by Yuan Zhu, Ben Tao, Mingkang Xiao, Gang Yang, Xingfu Zhang and Ke Lu
Electronics 2020, 9(8), 1325; https://doi.org/10.3390/electronics9081325 - 16 Aug 2020
Cited by 30 | Viewed by 6001
Abstract
Two problems can cause control performance degradation on permanent magnet synchronous motor (PMSM) systems, namely, fluctuation of PMSM parameters and the time delay between current sampling and command value update. In order to reduce the influence of these problems, a new current-predictive control [...] Read more.
Two problems can cause control performance degradation on permanent magnet synchronous motor (PMSM) systems, namely, fluctuation of PMSM parameters and the time delay between current sampling and command value update. In order to reduce the influence of these problems, a new current-predictive control strategy is proposed in this article for medium- and high-speed PMSM. This strategy is based on the discrete mathematical model of PMSM. This new control strategy consists of two main steps: First, an integrator is applied to calculate current compensation value; second, the predictive current value is obtained through deadbeat-current predictive method. The stability of predictive control system is also proved in the article. With this deadbeat-current predictive control scheme, the real current can reach the desired value within one control-step. Based on this new current control method, Luenberger observer and phase-locked loop position tracker is applied in this article. Experimental results for 0.4 kW surface-mounted PMSM confirm the validity and excellent performance for parameters fluctuation of new current predictive control. Full article
(This article belongs to the Section Industrial Electronics)
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21 pages, 3084 KiB  
Review
Supply-Scalable High-Speed I/O Interfaces
by Woorham Bae
Electronics 2020, 9(8), 1315; https://doi.org/10.3390/electronics9081315 - 15 Aug 2020
Cited by 9 | Viewed by 7734
Abstract
Improving the energy efficiency of computer communication is becoming more and more important as the world is creating a massive amount of data, while the interface has been a bottleneck due to the finite bandwidth of electrical wires. Introducing supply voltage scalability is [...] Read more.
Improving the energy efficiency of computer communication is becoming more and more important as the world is creating a massive amount of data, while the interface has been a bottleneck due to the finite bandwidth of electrical wires. Introducing supply voltage scalability is expected to significantly improve the energy efficiency of communication input/output (I/O) interfaces as well as make the I/Os efficiently adapt to actual utilization. However, there are many challenges to be addressed to facilitate the realization of a true sense of supply-scalable I/O. This paper reviews the motivations, background theories, design considerations, and challenges of scalable I/Os from the viewpoint of computer architecture down to the transistor level. Thereafter, a survey of the state-of-the-arts fabricated designs is discussed. Full article
(This article belongs to the Special Issue Low-Voltage Integrated Circuits Design and Application)
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22 pages, 926 KiB  
Article
Smart Fuzzy Logic-Based Density and Distribution Adaptive Scheme for Efficient Data Dissemination in Vehicular Ad Hoc Networks
by Elnaz Limouchi and Imad Mahgoub
Electronics 2020, 9(8), 1297; https://doi.org/10.3390/electronics9081297 - 12 Aug 2020
Cited by 11 | Viewed by 3072
Abstract
In vehicular Ad Hoc Networks (VANETs), smart data dissemination is crucial for efficient exchange of traffic and road information. Given the dynamic nature of VANET, the challenge is to design an adaptive multi-hop broadcast scheme that achieves high reachability while efficiently utilizing the [...] Read more.
In vehicular Ad Hoc Networks (VANETs), smart data dissemination is crucial for efficient exchange of traffic and road information. Given the dynamic nature of VANET, the challenge is to design an adaptive multi-hop broadcast scheme that achieves high reachability while efficiently utilizing the bandwidth by reducing the number of redundant transmissions. In this paper, we propose a novel intelligent fuzzy logic based density and distribution adaptive broadcast protocol for VANETs. The proposed protocol estimates the spatial distribution of vehicles in the network employing the Nearest Neighbor Distance method, and uses it to adapt the transmission range to enhance reachability. To reduce packet collisions, the protocol intelligently adapts the contention window size to the network density and spatial distribution. Bloom filter technique is used to reduce the overhead resulting from the inclusion of the neighbor IDs in the header of the broadcast message, which is needed in identifying the set of potential rebroadcasting vehicles. Our simulation results confirmed the effectiveness of the proposed scheme in enhancing reachability while efficiently utilizing bandwidth. Full article
(This article belongs to the Special Issue Recent Developments on Mobile Ad-Hoc Networks and Vehicular Ad-Hoc Networks)
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