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Electronics, Volume 9, Issue 5 (May 2020) – 178 articles

Cover Story (view full-size image): We have demonstrated the polarization-induced threshold voltage shift in an externally connected ferroelectric-gated field-effect transistor (FeFET) and have proposed a way to understand the operation of synaptic devices. The FeFET was fabricated by connecting a baseline 20 nm FinFET in series to a Pb(Zr0.52Ti0.48)O3 ferroelectric capacitor. As the starting gate voltage (from –4 to –0.5 V) or the ending gate voltage (from +4 to +2 V) is manipulated, the threshold voltage is modulated from 1.66 to 0.87 V or –0.6 to 1.04 V, respectively. This explicitly indicates the conductance modulation in the synaptic device. View this paper.
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Open AccessFeature PaperEditor’s ChoiceReview
A Survey on Through-the-Road Hybrid Electric Vehicles
Electronics 2020, 9(5), 879; https://doi.org/10.3390/electronics9050879 - 25 May 2020
Viewed by 1304
Abstract
Hybrid Electric Vehicles (HEVs) can be divided into three categories according to how the two propulsion systems (the thermal and the electric ones) supply the driving torque to the vehicle. When the torque is supplied only by an electric propulsion system, while the [...] Read more.
Hybrid Electric Vehicles (HEVs) can be divided into three categories according to how the two propulsion systems (the thermal and the electric ones) supply the driving torque to the vehicle. When the torque is supplied only by an electric propulsion system, while the heat engine takes care of generating the electricity needed to operate the system, it is called a hybrid-series. Conversely, when both propulsion systems provide torque, the vehicle is identified with parallel hybrid wording. Among the parallel hybrids there is a particular configuration called Through-the-Road (TTR). In this configuration, the two propulsion systems are not mechanically connected to each other, but it is precisely the road that allows hybrid propulsion. This architecture, dating back to the early twentieth century, is still used by several manufacturers and carries with it peculiar configurations and control methods. It is also a configuration that fits well with the transformation of conventional vehicles into a hybrid. The paper presents a survey of the TTR HEV solution, evidencing applications, potentialities and limits. Full article
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Open AccessArticle
CMOS Analog AGC for Biomedical Applications
Electronics 2020, 9(5), 878; https://doi.org/10.3390/electronics9050878 - 25 May 2020
Viewed by 1167
Abstract
In this paper, we present the design of an analog Automatic Gain Control with a small silicon area and reduced power consumption using a 0.5 μ m process. The design uses a classical approach implementing the AGC system with simple blocks, such as: peak detector, difference amplifier, four-quadrant multiplier, and inversor amplifier. Those blocks were realized by using a modified Miller type OPAMP, which allows indirect compensation, while the peak detector uses a MOS diode. The AGC design is simulated using the Tanner-Eda environment and Berkeley models BSIM49 of the On-Semiconductor C5 process, and it was fabricated through the MOSIS prototyping service. The AGC system has an operation frequency of around 1 kHz, covering the range of biomedical applications, power consumption of 200 μ W, and the design occupies a silicon area of approximately 508.8 μ m × 317.7 μ m. According to the characteristics obtained at the experimental level (attack and release time), this AGC can be applied to hearing aid systems. Full article
(This article belongs to the Section Bioelectronics)
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Open AccessArticle
Reliable Surrogate Modeling of Antenna Input Characteristics by Means of Domain Confinement and Principal Components
Electronics 2020, 9(5), 877; https://doi.org/10.3390/electronics9050877 - 25 May 2020
Cited by 1 | Viewed by 798
Abstract
A reliable design of contemporary antenna structures necessarily involves full-wave electromagnetic (EM) analysis which is the only tool capable of accounting, for example, for element coupling or the effects of connectors. As EM simulations tend to be CPU-intensive, surrogate modeling allows for relieving [...] Read more.
A reliable design of contemporary antenna structures necessarily involves full-wave electromagnetic (EM) analysis which is the only tool capable of accounting, for example, for element coupling or the effects of connectors. As EM simulations tend to be CPU-intensive, surrogate modeling allows for relieving the computational overhead of design tasks that require numerous analyses, for example, parametric optimization or uncertainty quantification. Notwithstanding, conventional data-driven surrogates are not suitable for handling highly nonlinear antenna characteristics over multidimensional parameter spaces. This paper proposes a novel modeling approach that employs a recently introduced concept of domain confinement, as well as principal component analysis. In our approach, the modeling process is restricted to the region containing high-quality designs with respect to the performance figures of antennas under design, identified using a set of pre-optimized reference designs. The model domain is spanned by the selected principal components of the reference design set, which reduces both its volume and dimensionality. As a result, a reliable surrogate can be constructed over wide ranges of both operating conditions and antenna parameters, using small training datasets. Our technique is demonstrated using two antenna examples and is favorably compared to both conventional and constrained modeling approaches. Application case studies (antenna optimization) are also discussed. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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Open AccessArticle
Use of Mobile Technologies in Personal Learning Environments of Intercultural Contexts: Individual and Group Tasks
Electronics 2020, 9(5), 876; https://doi.org/10.3390/electronics9050876 - 25 May 2020
Cited by 4 | Viewed by 1136
Abstract
This paper presents the results of the analysis of the personal learning environments (PLE) used individually and in groups by fifth grade primary education students. The main objective was to determine if the use of mobile technologies in the students’ PLEs encouraged their [...] Read more.
This paper presents the results of the analysis of the personal learning environments (PLE) used individually and in groups by fifth grade primary education students. The main objective was to determine if the use of mobile technologies in the students’ PLEs encouraged their school integration and learning in intercultural communities. For this, a content analysis of the students’ responses to an ad hoc interview was carried out, with a content validity index of 0.89. The students represented their answers using 41 concept maps in the individual tasks and 5 in the group tasks, which were analyzed with the Nvivo software in its latest version. The results show the categorization of the students’ responses in three dimensions: read, make/reflection and relationship. Among the main conclusions, it was obtained that, in both types of tasks, the strategies and tools that fostered intercultural relationships, intercultural education and communication between the students, and therefore school integration, are mostly linked to the use of mobile technologies applications, such as Wikipedia, the internet, Word, PowerPoint, social networks and YouTube, although it is essential to develop more studies to have more data to understand the phenomenon in depth. Full article
(This article belongs to the Special Issue Multidisciplinary Views on Mobile Communications)
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Open AccessArticle
Optimizing AC Resistance of Solid PCB Winding
Electronics 2020, 9(5), 875; https://doi.org/10.3390/electronics9050875 - 25 May 2020
Cited by 2 | Viewed by 1173
Abstract
At high frequency, power losses of a winding due to eddy currents becomes significant. Moreover, the skin and proximity AC resistances are influenced by the width of printed circuit board (PCB) conductors and distance between the adjacent tracks which causes many difficulties to [...] Read more.
At high frequency, power losses of a winding due to eddy currents becomes significant. Moreover, the skin and proximity AC resistances are influenced by the width of printed circuit board (PCB) conductors and distance between the adjacent tracks which causes many difficulties to design windings with lowest AC resistances. To clarify this phenomenon, this paper focuses on modeling the influence of skin and proximity effects on AC resistance of planar PCB winding, thereby providing guidelines to reduce the winding AC resistance. An approximate electromagnetic calculation method is proposed and it shows that when the winding proximity AC to DC ratio ( F p r o x i m i t y ) is equal to 1 3 the AC on DC ratio caused by skin effect ( F s k i n ) , the winding is optimized and it has lowest AC resistance. 3-D finite element simulations of 3, 7 and 10-Turn windings, which are divided into 3 groups with the same footprint, are presented to investigate the lowest AC resistance when the track width varies from 3 mm to 5 mm and the frequency range is up to 700 kHz. In order to verify the theoretical analysis and simulation results, an experiment with 3 simulated groups, (9 prototypes in total) is built and has a very good fit with simulation results. Experimental results show that at the optimal width, the AC resistance of the windings can be reduced up to 16.5 % in the frequency range from 200 kHz to 700 kHz. Full article
(This article belongs to the Special Issue Design and Optimization of High-Frequency Power Converter)
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Open AccessFeature PaperArticle
Selective Feature Anonymization for Privacy-Preserving Image Data Publishing
Electronics 2020, 9(5), 874; https://doi.org/10.3390/electronics9050874 - 25 May 2020
Viewed by 1383
Abstract
There is a strong positive correlation between the development of deep learning and the amount of public data available. Not all data can be released in their raw form because of the risk to the privacy of the related individuals. The main objective [...] Read more.
There is a strong positive correlation between the development of deep learning and the amount of public data available. Not all data can be released in their raw form because of the risk to the privacy of the related individuals. The main objective of privacy-preserving data publication is to anonymize the data while maintaining their utility. In this paper, we propose a privacy-preserving semi-generative adversarial network (PPSGAN) that selectively adds noise to class-independent features of each image to enable the processed image to maintain its original class label. Our experiments on training classifiers with synthetic datasets anonymized with various methods confirm that PPSGAN shows better utility than other conventional methods, including blurring, noise-adding, filtering, and generation using GANs. Full article
(This article belongs to the Special Issue Advances in Machine Learning)
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Open AccessArticle
A Function Reconfigurable Antenna Based on Liquid Metal
Electronics 2020, 9(5), 873; https://doi.org/10.3390/electronics9050873 - 24 May 2020
Cited by 3 | Viewed by 882
Abstract
To meet the demands of maritime transportation on ships, including satellite positioning, wireless communication, and radio frequency identification (RFID) for cargo handling management, a function reconfigurable antenna based on liquid metal is proposed in this paper. The antenna is composed of 3-D-printed hollow [...] Read more.
To meet the demands of maritime transportation on ships, including satellite positioning, wireless communication, and radio frequency identification (RFID) for cargo handling management, a function reconfigurable antenna based on liquid metal is proposed in this paper. The antenna is composed of 3-D-printed hollow cavities, a two-step impedance feeding sheet, and two feeding probes. The 3-D-printed hollow cavities contain a big hollow helix cavity, a hollow cone loaded cylinder cavity, four hollow cylinder cavities, and four small hollow helix cavities. By filling the liquid metal into different hollow cavities, reconfigurable functions are generated, including right-handed circular polarization (RHCP), omnidirectional linear polarization (O-LP), pattern reconfigurable circular polarization, and omnidirectional left-handed circular polarization (O-LHCP). To illustrate this, a prototype is fabricated using 3-D-printed photopolymer resin and etching technology. The measurement results agree well with the simulated ones in terms of return loss, radiation pattern, gain, and axial ratio (AR). For the five reconfigurable states, the measured relative bandwidths for |S11| < −10 dB are 44.7%, 41.7%, 30.4%, 28.1%, and 10.8%, respectively, which covers the bands of a global navigation satellite system (GNSS), wireless communication system, and RFID communication system. Attributing to the advantages of its compact structure, flexible conversion, and good performance, the proposed antenna is a good candidate for maritime transportation applications. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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Open AccessEditor’s ChoiceArticle
Design of a Low Power 10-b 8-MS/s Asynchronous SAR ADC with On-Chip Reference Voltage Generator
Electronics 2020, 9(5), 872; https://doi.org/10.3390/electronics9050872 - 24 May 2020
Cited by 4 | Viewed by 1268
Abstract
This paper presents an energy-efficient low power 10-b 8-MS/s asynchronous successive approximation register (SAR) analog-to-digital (ADC) converter. An inverted common-mode charge recovery technique is proposed to reduce the switching energy and to improve the linearity of the digital-to-analog converter (DAC). The proposed switching [...] Read more.
This paper presents an energy-efficient low power 10-b 8-MS/s asynchronous successive approximation register (SAR) analog-to-digital (ADC) converter. An inverted common-mode charge recovery technique is proposed to reduce the switching energy and to improve the linearity of the digital-to-analog converter (DAC). The proposed switching technique consumes only 149 CVREF2 switching energy for the 10-bit case. A rail-to-rail dynamic latch comparator is implemented with adaptive power control for better power efficiency. Additionally, to optimize the power consumption and performance of the logic part, a modified asynchronous type SAR control logic with digitally controllable delay cells is adopted. An on-chip reference voltage generator is also designed with an ADC core for practical use. The structure is realized using 55-nm complementary metal–oxide–semiconductor (CMOS) process technology. The proposed architecture achieves an effective number of bits (ENOB) of 9.56 bits and a signal-to-noise and distortion ratio (SNDR) level of 59.3 dB with a sampling rate of 8 MS/s at measurement level. The whole architecture consumes only 572 µW power when a power supply of 1 V is applied. Full article
(This article belongs to the Special Issue Analog/Digital Mixed Circuit and RF Transceiver Design)
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Open AccessFeature PaperArticle
An Optimized Balance of Plant for a Medium-Size PEM Electrolyzer: Design, Control and Physical Implementation
Electronics 2020, 9(5), 871; https://doi.org/10.3390/electronics9050871 - 24 May 2020
Viewed by 1249
Abstract
The progressive increase in hydrogen technologies’ role in transport, mobility, electrical microgrids, and even in residential applications, as well as in other sectors is expected. However, to achieve it, it is necessary to focus efforts on improving features of hydrogen-based systems, such as [...] Read more.
The progressive increase in hydrogen technologies’ role in transport, mobility, electrical microgrids, and even in residential applications, as well as in other sectors is expected. However, to achieve it, it is necessary to focus efforts on improving features of hydrogen-based systems, such as efficiency, start-up time, lifespan, and operating power range, among others. A key sector in the development of hydrogen technology is its production, renewable if possible, with the objective to obtain increasingly efficient, lightweight, and durable electrolyzers. For this, scientific works are currently being produced on stacks technology improvement (mainly based on two technologies: polymer electrolyte membrane (PEM) and alkaline) and on the balance of plant (BoP) or the industrial plant (its size depends on the power of the electrolyzer) that runs the stack for its best performance. PEM technology offers distinct advantages, apart from the high cost of its components, its durability that is not yet guaranteed and the availability in the MW range. Therefore, there is an open field of research for achievements in this technology. The two elements to improve are the stacks and BoP, also bearing in mind that improving BoP will positively affect the stack operation. This paper develops the design, implementation, and practical experimentation of a BoP for a medium-size PEM electrolyzer. It is based on the realization of the optimal design of the BoP, paying special attention to the subsystems that comprise it: the power supply subsystem, water management subsystem, hydrogen production subsystem, cooling subsystem, and control subsystem. Based on this, a control logic has been developed that guarantees efficient and safe operation. Experimental results validate the designed control logic in various operating cases, including warning and failure cases. Additionally, the experimental results show the correct operation in the different states of the plant, analyzing the evolution of the hydrogen flow pressure and temperature. The capacity of the developed PEM electrolysis plant is probed regarding its production rate, wide operating power range, reduced pressurization time, and high efficiency. Full article
(This article belongs to the Special Issue Intelligent Modelling and Control in Renewable Energy Systems)
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Open AccessArticle
Robustness and Unpredictability for Double Arbiter PUFs on Silicon Data: Performance Evaluation and Modeling Accuracy
Electronics 2020, 9(5), 870; https://doi.org/10.3390/electronics9050870 - 24 May 2020
Cited by 3 | Viewed by 988
Abstract
Classical cryptographic methods that inherently employ secret keys embedded in non-volatile memory have been known to be impractical for limited-resource Internet of Things (IoT) devices. Physical Unclonable Functions (PUFs) have emerged as an applicable solution to provide a keyless means for secure authentication. [...] Read more.
Classical cryptographic methods that inherently employ secret keys embedded in non-volatile memory have been known to be impractical for limited-resource Internet of Things (IoT) devices. Physical Unclonable Functions (PUFs) have emerged as an applicable solution to provide a keyless means for secure authentication. PUFs utilize inevitable variations of integrated circuits (ICs) components, manifest during the fabrication process, to extract unique responses. Double Arbiter PUFs (DAPUFs) have been recently proposed to overcome security issues in XOR PUF and enhance the tolerance of delay-based PUFs against modeling attacks. This paper provides comprehensive risk analysis and performance evaluation of all proposed DAPUF designs and compares them with their counterparts from XOR PUF. We generated different sets of real challenge–response pairs CRPs from three FPGA hardware boards to evaluate the performance of both DAPUF and XOR PUF designs using special-purpose evaluation metrics. We show that none of the proposed designs of DAPUF is strictly preferred over XOR PUF designs. In addition, our security analysis using neural network reveals the vulnerability of all DAPUF designs against machine learning attacks. Full article
(This article belongs to the Special Issue AI-Enabled Security and Privacy Mechanisms for IoT)
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Open AccessArticle
Continuous Gesture Recognition Based on Time Sequence Fusion Using MIMO Radar Sensor and Deep Learning
Electronics 2020, 9(5), 869; https://doi.org/10.3390/electronics9050869 - 23 May 2020
Cited by 2 | Viewed by 1044
Abstract
Gesture recognition that is based on high-resolution radar has progressively developed in human-computer interaction field. In a radar recognition-based system, it is challenging to recognize various gesture types because of the lacking of gesture transversal feature. In this paper, we propose an integrated [...] Read more.
Gesture recognition that is based on high-resolution radar has progressively developed in human-computer interaction field. In a radar recognition-based system, it is challenging to recognize various gesture types because of the lacking of gesture transversal feature. In this paper, we propose an integrated gesture recognition system that is based on frequency modulated continuous wave MIMO radar combined with deep learning network for gesture recognition. First, a pre-processing algorithm, which consists of the windowed fast Fourier transform and the intermediate-frequency signal band-pass-filter (IF-BPF), is applied to obtain improved Range Doppler Map. A range FFT based MUSIC (RFBM) two-dimensional (2D) joint super-resolution estimation algorithm is proposed to obtain a Range Azimuth Map to obtain gesture transversal feature. Range Doppler Map and Range Azimuth Map then respectively form a Range Doppler Map Time Sequence (RDMTS) and a Range Azimuth Map Time Sequence (RAMTS) in gesture recording duration. Finally, a Dual stream three-dimensional (3D) Convolution Neural Network combined with Long Short Term Memory (DS-3DCNN-LSTM) network is designed to extract and fuse features from both RDMTS and RAMTS, and then classify gestures with radial and transversal change. The experimental results show that the proposed system could distinguish 10 types of gestures containing transversal and radial motions with an average accuracy of 97.66%. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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Open AccessArticle
Optimized Lossless Embedded Compression for Mobile Multimedia Applications
Electronics 2020, 9(5), 868; https://doi.org/10.3390/electronics9050868 - 23 May 2020
Cited by 1 | Viewed by 930
Abstract
Power consumption is a critical design factor in modern mobile chip design, in which the memory system with dynamic random-access memory (DRAM) consumes more than half of the entire system’s power. Without DRAM bandwidth compression, extreme multimedia operations such as 8K high dynamic [...] Read more.
Power consumption is a critical design factor in modern mobile chip design, in which the memory system with dynamic random-access memory (DRAM) consumes more than half of the entire system’s power. Without DRAM bandwidth compression, extreme multimedia operations such as 8K high dynamic range (HDR) recording and 8K video conference calling are not possible without sacrificing image quality or trimming because of thermal limitations or battery time sustainability constraints. Since heterogeneous processors are substantially involved in managing various types of fallbacks or software solutions, complicated compression algorithms for high-compression ratios are not actually adaptable owing to timing closure problems or high throughput requirements. In this paper, we propose evaluation metrics to assess lossless embedded compression (LEC) algorithms to reflect realistic design considerations for mobile multimedia scenarios. Furthermore, we introduce an optimized LEC implementation for contemporary multimedia applications in mobile devices based on the proposed metrics. The proposed LEC implementation enhances the compression ratio of LEC algorithms in other commercial application processors for contemporary premium smartphones by up to 9.2% on average, while maintaining the same timing closure condition. Full article
(This article belongs to the Section Computer Science & Engineering)
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Open AccessArticle
3D Multiple Sound Source Localization by Proposed Cuboids Nested Microphone Array in Combination with Adaptive Wavelet-Based Subband GEVD
Electronics 2020, 9(5), 867; https://doi.org/10.3390/electronics9050867 - 23 May 2020
Viewed by 950
Abstract
Sound source localization is one of the applicable areas in speech signal processing. The main challenge appears when the aim is a simultaneous multiple sound source localization from overlapped speech signals with an unknown number of speakers. Therefore, a method able to estimate [...] Read more.
Sound source localization is one of the applicable areas in speech signal processing. The main challenge appears when the aim is a simultaneous multiple sound source localization from overlapped speech signals with an unknown number of speakers. Therefore, a method able to estimate the number of speakers, along with the speaker’s location, and with high accuracy is required in real-time conditions. The spatial aliasing is an undesirable effect of the use of microphone arrays, which decreases the accuracy of localization algorithms in noisy and reverberant conditions. In this article, a cuboids nested microphone array (CuNMA) is first proposed for eliminating the spatial aliasing. The CuNMA is designed to receive the speech signal of all speakers in different directions. In addition, the inter-microphone distance is adjusted for considering enough microphone pairs for each subarray, which prepares appropriate information for 3D sound source localization. Subsequently, a speech spectral estimation method is considered for evaluating the speech spectrum components. The suitable spectrum components are selected and the undesirable components are denied in the localization process. The speech information is different in frequency bands. Therefore, the adaptive wavelet transform is used for subband processing in the proposed algorithm. The generalized eigenvalue decomposition (GEVD) method is implemented in sub-bands on all nested microphone pairs, and the probability density function (PDF) is calculated for estimating the direction of arrival (DOA) in different sub-bands and continuing frames. The proper PDFs are selected by thresholding on the standard deviation (SD) of the estimated DOAs and the rest are eliminated. This process is repeated on time frames to extract the best DOAs. Finally, K-means clustering and silhouette criteria are considered for DOAs classification in order to estimate the number of clusters (speakers) and the related DOAs. All DOAs in each cluster are intersected for estimating the position of the 3D speakers. The closest point to all DOA planes is selected as a speaker position. The proposed method is compared with a hierarchical grid (HiGRID), perpendicular cross-spectra fusion (PCSF), time-frequency wise spatial spectrum clustering (TF-wise SSC), and spectral source model-deep neural network (SSM-DNN) algorithms based on the accuracy and computational complexity of real and simulated data in noisy and reverberant conditions. The results show the superiority of the proposed method in comparison with other previous works. Full article
(This article belongs to the Special Issue Indoor Positioning Techniques)
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Open AccessFeature PaperEditor’s ChoiceArticle
A Pipeline for Adaptive Filtering and Transformation of Noisy Left-Arm ECG to Its Surrogate Chest Signal
Electronics 2020, 9(5), 866; https://doi.org/10.3390/electronics9050866 - 23 May 2020
Viewed by 1036
Abstract
The performance of a low-power single-lead armband in generating electrocardiogram (ECG) signals from the chest and left arm was validated against a BIOPAC MP160 benchtop system in real-time. The filtering performance of three adaptive filtering algorithms, namely least mean squares (LMS), recursive least [...] Read more.
The performance of a low-power single-lead armband in generating electrocardiogram (ECG) signals from the chest and left arm was validated against a BIOPAC MP160 benchtop system in real-time. The filtering performance of three adaptive filtering algorithms, namely least mean squares (LMS), recursive least squares (RLS), and extended kernel RLS (EKRLS) in removing white (W), power line interference (PLI), electrode movement (EM), muscle artifact (MA), and baseline wandering (BLW) noises from the chest and left-arm ECG was evaluated with respect to the mean squared error (MSE). Filter parameters of the used algorithms were adjusted to ensure optimal filtering performance. LMS was found to be the most effective adaptive filtering algorithm in removing all noises with minimum MSE. However, for removing PLI with a maximal signal-to-noise ratio (SNR), RLS showed lower MSE values than LMS when the step size was set to 1 × 10−5. We proposed a transformation framework to convert the denoised left-arm and chest ECG signals to their low-MSE and high-SNR surrogate chest signals. With wide applications in wearable technologies, the proposed pipeline was found to be capable of establishing a baseline for comparing left-arm signals with original chest signals, getting one step closer to making use of the left-arm ECG in clinical cardiac evaluations. Full article
(This article belongs to the Section Microelectronics and Optoelectronics)
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Open AccessArticle
Mobility Management Based on Beam-Level Measurement Report in 5G Massive MIMO Cellular Networks
Electronics 2020, 9(5), 865; https://doi.org/10.3390/electronics9050865 - 23 May 2020
Viewed by 865
Abstract
Massive multiple-input-multiple-output (MMIMO) in the mmWave band is an essential technique to achieve the desired performance for 5G new radio (NR) systems. To employ mmWave MMIMO technology, an important challenge is maintaining seamless mobility to users because we need to consider beam-switching within [...] Read more.
Massive multiple-input-multiple-output (MMIMO) in the mmWave band is an essential technique to achieve the desired performance for 5G new radio (NR) systems. To employ mmWave MMIMO technology, an important challenge is maintaining seamless mobility to users because we need to consider beam-switching within a cell besides the handover between cells. For mobility management in 5G NR systems, 3GPP specified a beam-level-mobility scheme that includes beam pairing and maintenance between a transmitter (Tx) and receiver (Rx) pair. We propose a unific-measurement report based mobility management scheme for improved radio-link-failure (RLF) rate and the accuracy of the Tx-Rx-beam-pair (TRP) selection with low overhead in 5G mmWave MMIMO networks where both handover and beam-switching are required. Furthermore, we modeled a finite-state-machine (FSM) for a user terminal to evaluate performance gain based on a system-level-simulation (SLS). We use the FSM-based Monte-Carlo SLS for the experiment and compare the performance of the proposed scheme with that of existing schemes in the scenario where both beam and cell-level-mobility are necessary. We show that the proposed scheme achieves an improvement in terms of the 3-dB loss probabilities representing the accuracy of the TRP selection, signal-to-interference-and-noise-ratio (SINR), and RLF rates with a lower signaling overhead compared to existing methods. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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Open AccessArticle
Programming Pulse Width Assessment for Reliable and Low-Energy Endurance Performance in Al:HfO2-Based RRAM Arrays
Electronics 2020, 9(5), 864; https://doi.org/10.3390/electronics9050864 - 23 May 2020
Cited by 7 | Viewed by 1144
Abstract
A crucial step in order to achieve fast and low-energy switching operations in resistive random access memory (RRAM) memories is the reduction of the programming pulse width. In this study, the incremental step pulse with verify algorithm (ISPVA) was implemented by using different [...] Read more.
A crucial step in order to achieve fast and low-energy switching operations in resistive random access memory (RRAM) memories is the reduction of the programming pulse width. In this study, the incremental step pulse with verify algorithm (ISPVA) was implemented by using different pulse widths between 10 μ s and 50 ns and assessed on Al-doped HfO 2 4 kbit RRAM memory arrays. The switching stability was assessed by means of an endurance test of 1k cycles. Both conductive levels and voltages needed for switching showed a remarkable good behavior along 1k reset/set cycles regardless the programming pulse width implemented. Nevertheless, the distributions of voltages as well as the amount of energy required to carry out the switching operations were definitely affected by the value of the pulse width. In addition, the data retention was evaluated after the endurance analysis by annealing the RRAM devices at 150 °C along 100 h. Just an almost negligible increase on the rate of degradation of about 1 μ A at the end of the 100 h of annealing was reported between those samples programmed by employing a pulse width of 10 μ s and those employing 50 ns. Finally, an endurance performance of 200k cycles without any degradation was achieved on 128 RRAM devices by using programming pulses of 100 ns width. Full article
(This article belongs to the Special Issue Challenges and Applications of Non-volatile Memory)
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Open AccessArticle
Simultaneous Audio Encryption and Compression Using Compressive Sensing Techniques
Electronics 2020, 9(5), 863; https://doi.org/10.3390/electronics9050863 - 22 May 2020
Cited by 1 | Viewed by 786
Abstract
The development of coding schemes with the capacity to simultaneously encrypt and compress audio signals is a subject of active research because of the increasing necessity for transmitting sensitive audio information over insecure communication channels. Thus, several schemes have been developed; firstly, some [...] Read more.
The development of coding schemes with the capacity to simultaneously encrypt and compress audio signals is a subject of active research because of the increasing necessity for transmitting sensitive audio information over insecure communication channels. Thus, several schemes have been developed; firstly, some of them compress the digital information and subsequently encrypt the resulting information. These schemas efficiently compress and encrypt the information. However, they may compromise the information as it can be accessed before encryption. To overcome this problem, a compressing sensing-based system to simultaneously compress and encrypt audio signals is proposed in which the audio signal is segmented in frames of 1024 samples and transformed into a sparse frame using the discrete cosine transform (DCT). Each frame is then multiplied by a different sensing matrix generated using the chaotic mixing scheme. This fact allows that the proposed scheme satisfies the extended Wyner secrecy (EWS) criterion. The evaluation results obtained using several genres of audio signals show that the proposed system allows to simultaneously compress and encrypt audio signals, satisfying the EWS criterion. Full article
(This article belongs to the Section Circuit and Signal Processing)
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Open AccessArticle
BBR-CWS: Improving the Inter-Protocol Fairness of BBR
Electronics 2020, 9(5), 862; https://doi.org/10.3390/electronics9050862 - 22 May 2020
Cited by 3 | Viewed by 846
Abstract
TCP congestion control adjusts the sending rate in order to protect Internet from the continuous traffic and ensure fair coexistence among multiple flows. Especially, loss-based congestion control algorithms were mainly used, which worked relatively well for past Internet with low bandwidth and small [...] Read more.
TCP congestion control adjusts the sending rate in order to protect Internet from the continuous traffic and ensure fair coexistence among multiple flows. Especially, loss-based congestion control algorithms were mainly used, which worked relatively well for past Internet with low bandwidth and small bottleneck buffer size. However, the modern Internet uses considerably more sophisticated network equipment and advanced transmission technologies, and loss-based congestion control can cause performance degradation due to excessive queueing delay and packet loss. Therefore, Google introduced a new congestion control in 2016, Bottleneck Bandwidth Round-trip propagation time (BBR). In contrast with traditional congestion control, BBR tries to operate at the Kleinrock’s optimal operating point, where delivery rate is maximized and latency is minimized. However, when BBR and loss-based congestion control algorithms coexist on the same bottleneck link, most of bottleneck bandwidth is occupied by flows that use a particular algorithm, and excessive packet retransmission can occur. Therefore, this paper proposes a BBR congestion window scaling (BBR-CWS) scheme to improve BBR’s inter-protocol fairness with a loss-based congestion control algorithm. Through Mininet experiment results, we confirmed that fairness between BBR-CWS and CUBIC improved up to 73% and has the value of 0.9 or higher in most bottleneck buffer environments. Moreover, the number of packet retransmissions was reduced by up to 96%, compared to the original BBR. Full article
(This article belongs to the Special Issue Telecommunication Networks)
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Open AccessArticle
Location-Aware Point-to-Point RPL in Indoor IR-UWB Networks
Electronics 2020, 9(5), 861; https://doi.org/10.3390/electronics9050861 - 22 May 2020
Cited by 1 | Viewed by 752
Abstract
Wireless multi-hop ad hoc routing is one of the critical design factors that determine the network performance of various wireless IoT applications. IETF has standardized the point-to-point RPL (P2P-RPL) routing protocol to overcome the inefficient routing overheads of RPL. However, P2P-RPL propagates the [...] Read more.
Wireless multi-hop ad hoc routing is one of the critical design factors that determine the network performance of various wireless IoT applications. IETF has standardized the point-to-point RPL (P2P-RPL) routing protocol to overcome the inefficient routing overheads of RPL. However, P2P-RPL propagates the route discovery forwarding packets throughout the whole network. P2P-RPL suffers from the high energy consumption and the huge route discovery overhead in low-power and lossy networks (LLNs). In this paper, we propose a novel Location-Aware P2P-RPL (LA P2P-RPL), which achieves the energy-efficient P2P data delivery without reducing the networking reliability. The proposed algorithm introduces the Impulse-Response UWB (IR-UWB) based cooperative multi-hop self localization algorithm and the Location-Aware P2P-RPL algorithm for Indoor IR-UWB based networks. To increase the localization accuracy, smartphone based Inertial Navigation System (INS) with particle filtering is used in indoor multi-hop environments. The performance evaluations for Location-Aware P2P-RPL algorithm are compared with the traditional P2P-RPL and the ER-RPL algorithm to show the significant performance improvements for route discovery overheads and energy consumptions in LLNs. Full article
(This article belongs to the Section Networks)
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Open AccessArticle
Design of a Projectile-Borne Data Recorder Triggered by Overload
Electronics 2020, 9(5), 860; https://doi.org/10.3390/electronics9050860 - 22 May 2020
Viewed by 764
Abstract
The projectile-borne data recorder is used to measure and record the position and attitude data of exterior ballistic flights, which experience high overload during the launching process. The navigation algorithm can be optimized by analyzing the data stored in the recorder. As the [...] Read more.
The projectile-borne data recorder is used to measure and record the position and attitude data of exterior ballistic flights, which experience high overload during the launching process. The navigation algorithm can be optimized by analyzing the data stored in the recorder. As the primary means of acquiring the navigation data, the micro inertial measurement unit (MIMU) is an inevitable part of the projectile equipment. However, its mechanical structure could hardly bear the high overload during operation. In view of the above problems, a novel projectile-borne data recorder triggered by overload is designed in this paper. The recorder could have the navigation system powered when the projectile leaves the barrel so as to activate the data recording of the high overload. Furthermore, the viability of the MIMU of the high overload is guaranteed through a specific way of system encapsulation. In the proposed design, the overload switch redundancy and the power supply redundancy were adopted to improve reliability. The proposed design is tested with practical experiments, and the results show that the proposed recorder could be effectively triggered by overloading, and the supply voltage is stable, which helps record reliable data for the projectile. Full article
(This article belongs to the Special Issue Data Analysis in Intelligent Communication Systems)
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Open AccessArticle
A Multi-Objective Trajectory Planning Method for Collaborative Robot
Electronics 2020, 9(5), 859; https://doi.org/10.3390/electronics9050859 - 22 May 2020
Cited by 4 | Viewed by 911
Abstract
Aiming at the characteristics of high efficiency and smoothness in the motion process of collaborative robot, a multi-objective trajectory planning method is proposed. Firstly, the kinematics model of the collaborative robot is established, and the trajectory in the workspace is converted into joint [...] Read more.
Aiming at the characteristics of high efficiency and smoothness in the motion process of collaborative robot, a multi-objective trajectory planning method is proposed. Firstly, the kinematics model of the collaborative robot is established, and the trajectory in the workspace is converted into joint space trajectory using inverse kinematics method. Secondly, seven-order B-spline functions are used to construct joint trajectory sequences to ensure the continuous position, velocity, acceleration and jerk of each joint. Then, the trajectory competitive multi-objective particle swarm optimization (TCMOPSO) algorithm is proposed to search the Pareto optimal solutions set of the robot’s time-energy-jerk optimal trajectory. Further, the normalized weight function is proposed to select the appropriate solution. Finally, the algorithm simulation experiment is completed in MATLAB, and the robot control experiment is completed using the Robot Operating System (ROS). The experimental results show that the method can achieve effective multi-objective optimization, the appropriate optimal trajectory can be obtained according to the actual requirements, and the collaborative robot is actually operating well. Full article
(This article belongs to the Special Issue Modeling, Control, and Applications of Field Robotics)
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Open AccessArticle
A Detection Approach Using LSTM-CNN for Object Removal Caused by Exemplar-Based Image Inpainting
Electronics 2020, 9(5), 858; https://doi.org/10.3390/electronics9050858 - 22 May 2020
Cited by 2 | Viewed by 844
Abstract
Exemplar-based image inpainting technology is a “double-edged sword”. It can not only restore the integrity of image by inpainting damaged or removed regions, but can also tamper with the image by using the pixels around the object region to fill in the gaps [...] Read more.
Exemplar-based image inpainting technology is a “double-edged sword”. It can not only restore the integrity of image by inpainting damaged or removed regions, but can also tamper with the image by using the pixels around the object region to fill in the gaps left by object removal. Through the research and analysis, it is found that the existing exemplar-based image inpainting forensics methods generally have the following disadvantages: the abnormal similar patches are time-consuming and inaccurate to search, have a high false alarm rate and a lack of robustness to multiple post-processing combined operations. In view of the above shortcomings, a detection method based on long short-term memory (LSTM)-convolutional neural network (CNN) for image object removal is proposed. In this method, CNN is used to search for abnormal similar patches. Because of CNN’s strong learning ability, it improves the speed and accuracy of the search. The LSTM network is used to eliminate the influence of false alarm patches on detection results and reduce the false alarm rate. A filtering module is designed to eliminate the attack of post-processing operation. Experimental results show that the method has a high accuracy, and can resist the attack of post-processing combination operations. It can achieve a better performance than the state-of-the-art approaches. Full article
(This article belongs to the Section Computer Science & Engineering)
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Open AccessArticle
Electrical Material Properties of Carbon Reinforced Concrete
Electronics 2020, 9(5), 857; https://doi.org/10.3390/electronics9050857 - 21 May 2020
Viewed by 801
Abstract
Carbon fiber reinforced concrete is poised to be the building material of the future. We present a study to quantify the influence of this novel reinforcement material on RF propagation in the range from 0.4 to 67 GHz. The measured attenuation effects of [...] Read more.
Carbon fiber reinforced concrete is poised to be the building material of the future. We present a study to quantify the influence of this novel reinforcement material on RF propagation in the range from 0.4 to 67 GHz. The measured attenuation effects of the reinforcement material are explained and quantified using a metallic wire screen model. It can be used to as a simple model of the material’s influence in radio propagation scenarios. For reference and completeness, data on the complex dielectric permittivity of the investigated concrete brand is also included. The production process of the concrete samples used for the measurements is documented, facilitating comparability and reproducibility. Finally, implications for current and future radio communication applications are outlined. Full article
(This article belongs to the Section Microwave and Wireless Communications)
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Open AccessArticle
Learning Ratio Mask with Cascaded Deep Neural Networks for Echo Cancellation in Laser Monitoring Signals
Electronics 2020, 9(5), 856; https://doi.org/10.3390/electronics9050856 - 21 May 2020
Viewed by 785
Abstract
Laser monitoring has received more and more attention in many application fields thanks to its essential advantages. The analysis shows that the target speech in the laser monitoring signals is often interfered by the echoes, resulting in a decline in speech intelligibility and [...] Read more.
Laser monitoring has received more and more attention in many application fields thanks to its essential advantages. The analysis shows that the target speech in the laser monitoring signals is often interfered by the echoes, resulting in a decline in speech intelligibility and quality, which in turn affects the identification of useful information. The cancellation of echoes in laser monitoring signals is not a trivial task. In this article, we formulate it as a simple but effective additive echo noise model and propose a cascade deep neural networks (C-DNNs) as the mapping function from the acoustic feature of noisy speech to the ratio mask of clean signal. To validate the feasibility and effectiveness of the proposed method, we investigated the effect of echo intensity, echo delay, and training target on the performance. We also compared the proposed C-DNNs to some traditional and newly emerging DNN-based supervised learning methods. Extensive experiments demonstrated the proposed method can greatly improve the speech intelligibility and speech quality of the echo-cancelled signals and outperform the comparison methods. Full article
(This article belongs to the Special Issue Theory and Applications in Digital Signal Processing)
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Open AccessFeature PaperArticle
Analog Realization of a Fractional Recursive Variable-Type and Order Operator for a Particular Switching Strategy
Electronics 2020, 9(5), 855; https://doi.org/10.3390/electronics9050855 - 21 May 2020
Viewed by 732
Abstract
In this paper, we propose a method of practical realization and an actual, physical hardware implementation of a fractional variable-type and order difference operator that switches between two (i.e., B - and D -type) variable-order definitions. After the theoretical model of such a switch, we report the experimental validation on an analog model to prove its adequacy. The tests prove with great certainty that the proposed model and the realization behave correctly. They also let the authors assume that the proposed method is the only one suitable for this case, based on the counterexamples presented. Full article
(This article belongs to the Special Issue Fractional-Order Circuits & Systems Design and Applications)
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Open AccessArticle
A Learning Frequency-Aware Feature Siamese Network for Real-Time Visual Tracking
Electronics 2020, 9(5), 854; https://doi.org/10.3390/electronics9050854 - 21 May 2020
Viewed by 775
Abstract
Visual object tracking by Siamese networks has achieved favorable performance in accuracy and speed. However, the features used in Siamese networks have spatially redundant information, which increases computation and limits the discriminative ability of Siamese networks. Addressing this issue, we present a novel [...] Read more.
Visual object tracking by Siamese networks has achieved favorable performance in accuracy and speed. However, the features used in Siamese networks have spatially redundant information, which increases computation and limits the discriminative ability of Siamese networks. Addressing this issue, we present a novel frequency-aware feature (FAF) method for robust visual object tracking in complex scenes. Unlike previous works, which select features from different channels or layers, the proposed method factorizes the feature map into multi-frequency and reduces the low-frequency information that is spatially redundant. By reducing the low-frequency map’s resolution, the computation is saved and the receptive field of the layer is also increased to obtain more discriminative information. To further improve the performance of the FAF, we design an innovative data-independent augmentation for object tracking to improve the discriminative ability of tracker, which enhanced linear representation among training samples by convex combinations of the images and tags. Finally, a joint judgment strategy is proposed to adjust the bounding box result that combines intersection-over-union (IoU) and classification scores to improve tracking accuracy. Extensive experiments on 5 challenging benchmarks demonstrate that our FAF method performs favorably against SOTA tracking methods while running around 45 frames per second. Full article
(This article belongs to the Special Issue Deep Learning Technologies for Machine Vision and Audition)
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Open AccessFeature PaperEditor’s ChoiceReview
Network Management and Monitoring Solutions for Vehicular Networks: A Survey
Electronics 2020, 9(5), 853; https://doi.org/10.3390/electronics9050853 - 21 May 2020
Cited by 2 | Viewed by 1142
Abstract
Vehicular networks are emerging as a promising technology that enables reliable and low-cost solutions for intelligent transport systems (ITSs), mainly due to their enormous potential to be considered for multiple purposes and scenarios. These networks are characterized by unique and challenging features such [...] Read more.
Vehicular networks are emerging as a promising technology that enables reliable and low-cost solutions for intelligent transport systems (ITSs), mainly due to their enormous potential to be considered for multiple purposes and scenarios. These networks are characterized by unique and challenging features such as packet fragmentation, low node density, short contact duration, and network disruption. These features may result in the absence of a path between the source and destination nodes, which is one of the most challenging issues faced by this type of network. To overcome some of these problems, it is necessary to provide vehicular networks with sophisticated tools or methodologies to implement monitoring and management operations. However, designing efficient solutions for this type of network is not an easy task due to its particular characteristics. This paper elaborates on a comprehensive survey focusing on promising proposals to deal with monitoring and management functionalities in vehicular networks. This work aims not only to present the state of the art on monitoring and management solutions but also to analyze their benefits and drawbacks, identify open issues, and provide guidelines for further contributions. Full article
(This article belongs to the Special Issue Delay Tolerant Networks and Applications)
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Open AccessArticle
A Blockchain and Machine Learning-Based Drug Supply Chain Management and Recommendation System for Smart Pharmaceutical Industry
Electronics 2020, 9(5), 852; https://doi.org/10.3390/electronics9050852 - 21 May 2020
Cited by 5 | Viewed by 2611
Abstract
From the last decade, pharmaceutical companies are facing difficulties in tracking their products during the supply chain process, allowing the counterfeiters to add their fake medicines into the market. Counterfeit drugs are analyzed as a very big challenge for the pharmaceutical industry worldwide. [...] Read more.
From the last decade, pharmaceutical companies are facing difficulties in tracking their products during the supply chain process, allowing the counterfeiters to add their fake medicines into the market. Counterfeit drugs are analyzed as a very big challenge for the pharmaceutical industry worldwide. As indicated by the statistics, yearly business loss of around $200 billion is reported by US pharmaceutical companies due to these counterfeit drugs. These drugs may not help the patients to recover the disease but have many other dangerous side effects. According to the World Health Organization (WHO) survey report, in under-developed countries every 10th drug use by the consumers is counterfeit and has low quality. Hence, a system that can trace and track drug delivery at every phase is needed to solve the counterfeiting problem. The blockchain has the full potential to handle and track the supply chain process very efficiently. In this paper, we have proposed and implemented a novel blockchain and machine learning-based drug supply chain management and recommendation system (DSCMR). Our proposed system consists of two main modules: blockchain-based drug supply chain management and machine learning-based drug recommendation system for consumers. In the first module, the drug supply chain management system is deployed using Hyperledger fabrics which is capable of continuously monitor and track the drug delivery process in the smart pharmaceutical industry. On the other hand, the N-gram, LightGBM models are used in the machine learning module to recommend the top-rated or best medicines to the customers of the pharmaceutical industry. These models have trained on well known publicly available drug reviews dataset provided by the UCI: an open-source machine learning repository. Moreover, the machine learning module is integrated with this blockchain system with the help of the REST API. Finally, we also perform several tests to check the efficiency and usability of our proposed system. Full article
(This article belongs to the Special Issue Blockchain Based Electronic Healthcare Solution and Security)
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Open AccessFeature PaperArticle
Improved RSSI-Based Data Augmentation Technique for Fingerprint Indoor Localisation
Electronics 2020, 9(5), 851; https://doi.org/10.3390/electronics9050851 - 21 May 2020
Cited by 2 | Viewed by 854
Abstract
Recently, deep-learning-based indoor localisation systems have attracted attention owing to their higher performance compared with traditional indoor localization systems. However, to achieve satisfactory performance, the former systems require large amounts of data to train deep learning models. Since obtaining the data is usually [...] Read more.
Recently, deep-learning-based indoor localisation systems have attracted attention owing to their higher performance compared with traditional indoor localization systems. However, to achieve satisfactory performance, the former systems require large amounts of data to train deep learning models. Since obtaining the data is usually a tedious task, this requirement deters the use of deep learning approaches. To address this problem, we propose an improved data augmentation technique based on received signal strength indication (RSSI) values for fingerprint indoor positioning systems. The technique is implemented using available RSSI values at one reference point, and unlike existing techniques, it mimics the constantly varying RSSI signals. With this technique, the proposed method achieves a test accuracy of 95.26% in the laboratory simulation and 94.59% in a real-time environment, and the average location error is as low as 1.45 and 1.60 m, respectively. The method exhibits higher performance compared with an existing augmentation method. In particular, the data augmentation technique can be applied irrespective of the positioning algorithm used. Full article
(This article belongs to the Special Issue Innovative Technologies in Telecommunication)
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Open AccessArticle
ASFIT: AUTOSAR-Based Software Fault Injection Test for Vehicles
Electronics 2020, 9(5), 850; https://doi.org/10.3390/electronics9050850 - 20 May 2020
Viewed by 994
Abstract
With recent increases in the amount of software installed in vehicles, the probability of automotive software faults that lead to accidents has also increased. Because automotive software faults can lead to serious accidents or even mortalities, vehicle software design and testing must consider [...] Read more.
With recent increases in the amount of software installed in vehicles, the probability of automotive software faults that lead to accidents has also increased. Because automotive software faults can lead to serious accidents or even mortalities, vehicle software design and testing must consider safety a top priority. ISO 26262 recommends fault injection testing as a measure to verify the functional safety of vehicles. However, the standard does not clearly specify when and where faults should be injected, and the tools to support fault injection testing for automotive software are also insufficient. In the present study, we define faults that may occur in Automotive Open System Architecture (AUTOSAR)-based automotive software and propose a fault injection method to be applied during the software development process. The proposed method can inject different types of faults that may occur in AUTOSAR-based automotive software, such as access, asymmetric, and timing errors, while minimizing performance degradation due to fault injection, and without using any separate hardware devices. The superior performance of the proposed method is demonstrated through empirical studies applied to fault injection testing of a range of vehicle electronic control unit software. Full article
(This article belongs to the Special Issue Software Verification and Validation for Embedded Systems)
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