bluuebunny/crossref_metadata_2025_split huggingface dataset:
Constrained tolerance rough set in incomplete information systems
Authors: Wan Renxia , Miao Duoqian , Pedrycz Witold 
Published: April 2021

AbstractThe tolerance rough set is developed as one of the outstanding extensions of the Pawlak's rough set model under incomplete information, and the limited tolerance relation is developed to overcome the problem that objects leniently satisfy the tolerance relation. However, the classification based on the limited tolerance relationship cannot reflect the matching degree of uncertain information of objects. In this article, we explore the influence of null values in an incomplete system, and propose the constrained tolerance relation based on the matching degree of uncertain information of objects. The proposed rough set based on the constrained tolerance relation can provide a more detailed structure of an object class through threshold. Proofs and example analyses further show the rationality and superiority of the proposed model.
Content‐based image retrieval using Gaussian–Hermite moments and firefly and grey wolf optimization
Authors: Tadepalli Yasasvy , Kollati Meenakshi , Kuraparthi Swaraja , Kora Padmavathi , Budati Anil Kumar , Kala Pampana Lakshmi 
Published: April 2021

AbstractRapid growth in the transfer of multimedia information over the Internet requires algorithms to retrieve a queried image from large image database repositories. The proposed content‐based image retrieval (CBIR) uses Gaussian–Hermite moments as the low‐level features. Later these features are compressed with principal component analysis. The compressed feature set is multiplied with the weight matrix array, which has the same size as the feature vector. Hybrid firefly and grey wolf optimization (FAGWO) is used to prevent the premature convergence of optimization in the firefly algorithm. The retrieval of images in CBIR is carried out in an OpenCV python environment with K‐nearest neighbours and random forest algorithm classifiers. The fitness function for FAGWO is the accuracy of the classifier. The FAGWO algorithm derives the optimum weights from a randomly generated initial population. When these optimized weights are applied, the proposed algorithm shows better precision/recall and efficiency than other techniques such as exact legendre moments, Region‐based image retrieval, K‐means clustering ​and Color descriptor wavelet‐based texture descriptor retrieval technique. In terms of optimization, hybrid FAGWO outperformed various optimization techniques (when used alone) like Particle Swarm Optmization, Genetic Algorithm, Grey‐Wolf Optimization and FireFly algorithm.
Cyber‐physical component ranking for risk sensitivity analysis using betweenness centrality
Authors: Umunnakwe Amarachi , Sahu Abhijeet , Narimani Mohammad Rasoul , Davis Katherine , Zonouz Saman 
Published: April 2021

AbstractThis article proposes a model for critical component ranking in power system risk analysis using a proposed cyber‐physical betweenness centrality (CPBC) index. Risk assessment, as part of the contingency analysis, is a critical activity that can identify and evaluate component outages that lead to system vulnerability, aiding operators to improve resilience. A power system cyber‐physical risk assessment model is proposed that calculates and offers an efficient protection strategy to the system operator based on component vulnerability to adversaries and the impact of compromised assets on the system operation. We present the CPBC index, which traverses generated attack graphs to rank components according to their importance in reducing adversary impact on the power system. The CPBC extends upon betweenness centrality and integrates into analysis, the services and security cost of communications between system components, as well as the likelihood of component exploitation as an adversary medium to the target relays. The proposed model recommends actions, taking into account the interconnections between cyber and physical components as well as cyber‐induced Common Vulnerabilities and Exposure scores associated with these connections, thus protecting critical components. The proposed model is implemented on the Cyber‐Physical Situational Awareness 8‐substation and extended IEEE 300‐bus cyber‐physical power system models, and results are presented on the impacts of the proposed component ranking model on the security‐aware operation of the power system.
H∞ containment control with time‐varying delays and communicate noise under semi‐Markov switching topologies
Authors: Ru Xinfeng , Wu Mengjie , Liu Weifeng , Ge Quanbo , Peng Zhangming 
Published: April 2021

AbstractThis article focuses on H

∞
containment control and the communication network topologies that are driven by a semi‐Markov chain. Moreover, the communication channels between agents exist time‐varying delays and noise. Firstly, the authors extend the Markov switching topologies to semi‐Markov switching topologies. Because the transition rate of the semi‐Markov switching topology is time‐varying and depends on the sojourn time, the analysis of containment control under semi‐Markov switching topology becomes more challenging. Secondly, a control protocol with time‐varying delays is adopted. The error function is derived by the property of graph theory, convex hull and communication noise. Hence, the problem of H

∞
containment control is transformed into the stability problem of the semi‐Markov jump system. To avoid the zero initial condition in the traditional H

∞
control approach, a novel performance function is constructed with the initial condition considered. Finally, simulation experiments are provided to verify the effectiveness of the proposed algorithm.
A polarisation‐analysing CMOS image sensor for sensitive polarisation modulation detection
Authors: Okada R. , Sasagawa K. , Haruta M. , Takehara H. , Tashiro H. , Ohta J. 
Published: April 2021

AbstractIn this study, a polarisation‐analysing CMOS image sensor is fabricated for sensitive polarisation modulation detection. Although the image sensor with on‐pixel polarisers can image the incident polarisation collectively, its sensitivity to a weak polarisation change is not high. With the proposed method, an external polariser is used to enhance the polarisation modulation sensitivity with a polarisation image sensor. The performance of this highly sensitive polarisation image sensor and imaging experiments are evaluated using a flow channel.
A method for fault recognition in the last three rounds of Advanced Encryption Standard
Authors: Jiang Huilong , Zhu Xiang , Pang Jinfeng , Liu Zhipeng , Han Jianwei , Li Yue 
Published: April 2021

AbstractA large number of studies are there for Advanced Encryption Standard (AES) fault attack analysis, but less for fault recognition. This paper presents a recognition method for single‐byte fault which is induced in the last three rounds of AES. Studying the differential characteristics of Sbox, the single byte fault induced in ninth round or tenth round will be identified respectively with 9.3 and 9.1 ciphertexts. For the fault induced in eighth round, the fault value can be obtained with 188.5 ciphertexts by analyzing the differential features of two Sboxes and MixColumns. As an auxiliary means for fault attacks, this method is used to realize the byte or bit level physical positioning of confidential data in the encryption chip, which is beneficial to reduce the blindness of the attacker's experiments and obtain the sensitive area of fault attack.
E‐band InAs quantum dot laser on InGaAs metamorphic buffer layer with filter layer
Authors: Kwoen J. , Zhan W. , Arakawa Y. 
Published: April 2021

AbstractInAs quantum dots (QDs) are receiving attention as next‐generation E‐band light source that offers high‐temperature operation and temperature insensitive operation. However, high‐density crystal defects occur at the interface between the InGaAs buffer layer and GaAs, resulting in reduced device performance and shortened lifetime. Here, E‐band QD lasers are demonstrated on InGaAs buffer layer, which suppressed the spread of dislocation by introducing a high‐temperature annealing and a strained layer superlattice filter. In the device, the peak wavelength at room temperature is measured to be 1427 nm and the threshold current density was 440 A/cm2. This result indicates that E‐band QD laser structures on low threading dislocation density are promising for the realisation of high‐performance E‐band lasers.
Improved hybrid scheduling design of partitioned processing and network communication in distributed integrated modular avionics systems
Authors: Zhou Xuan , He Feng , Li Ershuai , Liu Jianhua , Xiong Huagang 
Published: April 2021

AbstractTraditional hybrid scheduling method of partitioned processing and network communication restricts the schedulability of distributed integrated modular avionics (DIMA) systems according to strict constraints. This paper loosens these constraints by introducing harmonic partitions, converts the hybrid scheduling design into a nonlinear optimization problem, and proposes an improved method based on the tabu search metaheuristic. Comparative experiments demonstrate that this method adapts to a larger‐scale system including 50 partitions and 1000 messages and guarantees lower processing‐level end‐to‐end delay with an average optimization of 48%.
Convolutional neural network‐based power system frequency security assessment
Authors: Wang Changjiang , Li Benxin , Liu Chunxiao , Li Peng 
Published: April 2021

AbstractWeak inertia characteristics of power systems with high penetrations of renewables have become a prominent problem for frequency security. To solve this problem, a convolutional neural network (CNN)‐based deep learning approach is applied to realize rapid frequency security assessment (FSA). First, the time series frequency security feature is autonomously mined from the wide‐area measurement data to serve as the input data. By doing so, the complex construction process of frequency security feature quantity is avoided. A deep learning structure is then used to establish a non‐linear mapping relationship between time series features and frequency security indicators to realize end‐to‐end power system frequency security prediction. Next, the evaluation accuracy of the proposed approach is optimized by tuning the key parameters in the CNN‐based evaluation model. Through data measurement error analysis and a wind penetration sensitivity study, the anti‐interference performance of the proposed evaluation model is demonstrated. Finally, the effectiveness of the CNN‐based FSA is verified by case studies of a modified 16‐machine 68‐node system and the China Southern Power Grid.
Life cycle cost assessment method considering multiple factors for economic evaluation of cable line steel brackets
Authors: Zhang Yujiao , Wang Zhenliang , Zhu Yanyan , Huang Xiongfeng , Wang Yaxin 
Published: April 2021

AbstractIn China, the bracket of underground high voltage cable transmission line is mainly made of various carbon steels. However, no unified standard exists for type selection of cable brackets in practice. Here, a selection method of the bracket based on life cycle cost assessment is proposed from the viewpoint of technical economy, in which the size of brackets, steel grade, carbon steel corrosion and eddy current loss are considered as influencing factors to the costs. Stress performance analysis under identical pole arm stress constraints is employed to determine the size and grade of carbon steel which influences the initial cost. And 3D coupled electromagnetic fluid‐dynamical and thermal finite‐element analysis is applied to calculate the eddy current loss of cable brackets which influences the operation cost. Meanwhile, multi‐physics coupling analysis and experiment are conducted to prove the correctness of loss simulation calculation. Tafel curve measured by electrochemical corrosion experiment is used to obtain the corrosion rate of carbon steel which influences the maintenance cost by affecting service life of brackets. A case study is demonstrated, and the results show that the channel steel type is the most economical for the commendatory and the proposed method is effective.
Hybrid flexible arc suppression device based on soft grid connection strategy for MV distribution systems
Authors: Zheng Ze‐Yin , Guo Mou‐Fa , Jin Tao , Liu Jian‐Hong 
Published: April 2021

AbstractAs an essential apparatus in resonance grounding systems, the arc suppression coil is widely used in rejecting the single‐line‐to‐ground (SLG) fault of distribution networks. However, the resistive ground‐fault current cannot be compensated by an arc suppression coil (ASC). As a novel active arc suppression device, the hybrid flexible arc suppression device (HFASD) composed of ASC and flexible arc suppression device (FASD) can eliminate the capacitive component of ground‐fault current and the resistive component of ground‐fault current. After the SLG fault occurs, the FASD from stand‐alone mode to grid‐connected mode may lead to switching transients, affecting the stability of distribution networks. The soft grid connection (SGC) strategy can achieve low or without transient response during the grid synchronization of FASD to the grid. Thus, the HFASD based on SGC strategy and segmented proportional‐integral‐differential (SPID) and second‐order generalized integrator phase‐locked loop (SOGI‐PLL) control method is proposed for rejecting the current and voltage overshoot responses during the process of grid synchronization of FASD in this paper. Simulation and experimental results verify the effectiveness of the proposed method, and the benefit of the proposed method is indicated in comparison with the non‐SGC (NSGC) strategy.
Partial discharge detection and identification at low air pressure in noisy environment
Authors: Nasr Esfahani Ali , Shahabi Saeed , Kordi Behzad 
Published: April 2021

AbstractIncreasing demand for electric power in more electric aircraft requires a higher operating voltage for the power system that leads to higher electric stress on the insulation system. Operating at high altitudes where the electrical strength of air is weakened exposes the insulation system to even higher levels of electrical stress. As such, the probability of partial discharges (PD), which result in insulation degradation and failure, is higher. The presence of switching circuits in the power distribution system of the more electric aircraft is capable of producing high levels of noise. This noise in combination with the background noise and parasitic impedances will cause high amplitude ringing in the measured partial discharge signal waveform. Here, a method based on the combination of the wavelet and energy techniques is employed to detect PD pulses in a noisy environment under the low air pressure condition. To verify the technique, a laboratory setup consisting of two separate PD sources mounted in low air pressure (33 kPa) chamber is developed where sine and square waveforms are used as the applied voltage. The obtained results demonstrate that the proposed approach offers low computational complexity, high performance in PD phase localization, and robustness in a noisy environment.
Insulation structure design and electric field simulation of 500 kV isolation energy supply transformer for HVDC breaker
Authors: Zhang Sheng , Fan Yadong , Lei Qingquan , Wang Jianguo , Liu Yuan , Zhan Ting 
Published: April 2021

AbstractThe high‐voltage isolated energy supply transformer (HIET) is the key component of the HVDC breaker, which is used for energy transmission and the potential isolation. There is a lack of research results that can meet engineering applications at home and abroad. The design of a 500 kV HIET with dry‐type insulation is proposed, using 10 cascade connected 50 kV sub‐transformers (STs), which uses silicon rubber suitable for DC voltage as the main insulation material. High‐voltage (HV) winding of ST adopts double‐shielding structure of coil semi‐conductive shielding and inner semi‐conductive shielding to improve electric field distribution. The simulation analysis of an electric field at different insulation thicknesses and temperatures shows that the electric field decreases with an increase in thickness of insulation. When the thickness is greater than 25 mm, the electric field reduction effect is significantly weakened. The electric field is closely related to temperature, when at 20°C, the electric field between double‐shielding is relatively uniform. When at 70°C, the inner shielding electric field is much higher than coil shielding, and undergoes obvious reversal. In addition, the 500 kV HIET's electric field has been analysed. The 50 0kV HIET prototype has been manufactured and passed the type test, and successfully applied to the 500 kV Zhangbei DC grid project.
Multilook phase difference distribution for slightly rough boundary layered ground
Authors: Afifi Saddek , Dusséaux Richard 
Published: April 2021

AbstractThe authors derive the distribution of the phase difference between two multilook scattering signals for a multilayer stack with randomly rough surfaces under a plane wave excitation. First, for infinite slightly rough surfaces described by Gaussian centred stochastic processes, the authors show that the underlying complex scattering signals follow a Gaussian joint distribution. Also, it is demonstrated that this property is within the scope of the first‐order perturbation theory. Secondly, the authors use this joint probability law to derive the closed‐form expression for the probability density function of the phase difference. The theoretical formula is verified by comparison with Monte‐Carlo simulations.
Wideband circularly polarised antenna array with isoflux pattern
Authors: Zeng Fanchao , Zhang Zhi‐Ya , Feng Yang , Zuo Shaoli , Zhang Chengbin , Wang Li 
Published: April 2021

AbstractThe authors present a wideband circularly polarised antenna array consisting of a 10‐element ellipse dipole antenna and a feed network. A metal pillar is vertically loaded at the end of each ellipse dipole arm to extend the current path, thereby reducing the lateral dimension of the antenna element. For uniform coverage over the Earth's surface, antenna with an isoflux pattern is required due to its uniform power density over a wide coverage area. To obtain wideband and isoflux characteristics, the amplitude and phase distributions along the network are optimised by applying the hybrid of the genetic algorithm and particle swarm optimisation. Particularly, the feed network with broadband phase shifting performance is designed to attain a broad bandwidth requirement. The proposed antenna can achieve excellent impedance matching and axial ratio characteristics from 1.1 to 1.6 GHz. In addition, the isoflux radiation pattern is obtained with the beamwidth of ±21° where the gain is higher than 0 dBi in the elevation plane (xoz‐Plane). The realised gain is better than 10.2 dBi and the side lobes are below −14.2dB across the operating frequency. Finally, the antenna array is manufactured and measured, and good agreement is achieved between the simulation and measurement results.
Planar wide‐angle and polarisation‐insensitive ultrathin frequency selective surface patch absorber design analysis and implementation
Authors: Abdalla Yasmine , Hammad Hany 
Published: April 2021

AbstractSingle‐layer ultrathin absorber patch elements are analysed under normal and oblique incidence. A compensation technique for impedance variation with an angle of incidence (θ) is proposed. An equivalent‐circuit model is formulated that provides a realisation for the absorption response (in terms of resonance frequency and absorption ratio) of non‐complicated rectangular patch absorbers using simple equations. The design methodology proposed is based on using multiple subcells of simple patches to add another degree of freedom for the design equations and keep the ultrathin planar feature. Previously reported techniques realising a wide angle of incidence are applied for fair comparison with the proposed methodology. The developed structure features angular stability, polarisation insensitivity, and a planar non‐complicated configuration compared with that of structures reported in literature. Moreover, a prototype is fabricated and measured to validate the proposed approach.
Meander‐line‐loaded circularly polarized square‐slot antenna with inverted‐L‐shaped feed line for C‐band applications
Authors: Midya Manas , Ghosh Anumoy , Mitra Monojit 
Published: April 2021

AbstractA compact broadband circularly polarized square‐slot antenna based on an offset‐fed inverted‐L‐shaped microstrip feed line is proposed. A rectangular slot beneath the feed line and an inverted‐L‐shaped grounded strip on the left bottom corner of the wide square slot produce dual‐wideband circular polarization (CP) coverage in a compact size. Meander lines with a square slot loaded at the right bottom corner of the ground plane result in broadband CP through overlapping of the dual‐wideband axial ratio (AR) bandwidths. The magnitude and phase differences between two field components can be controlled effectively with proper tuning of the square slot dimensions (4.5 × 4.5 mm2), which is helpful for broadening AR bandwidth over the C‐band by minimizing AR values (≤3 dB). The overall dimensions of the prototype are only 26 × 26 × 1.6 mm3. The antenna prototype has been validated experimentally. The measured results indicate an impedance bandwidth of 104% (3.56–11.22 GHz) and a 3 dB AR bandwidth of 76% (3.90–8.72 GHz). A peak gain of 3.4–4.42 dBi is achieved within the AR bandwidth. The proposed antenna is suitable for CP applications in the C‐band.
Performance enhancement of optical camera communication system using optical camera communication coding and region‐of‐interest detection
Authors: Nguyen Duy Thong , Park Youngil 
Published: April 2021

AbstractOptical camera communication (OCC) is considered an important transmission scheme in implementing indoor navigation, beacons, and other Internet of Things applications. One of the disadvantages of OCC, however, is that transmission is successful only if the line‐of‐sight requirement is satisfied between transmitting LED lamps and receiving image sensors. Any obstacle between them or movement of the receiver direction causes a reduction in the light signal and leads to a burst error, and its compensation is not easy. A low‐density parity check (LDPC) code is employed in the OCC to overcome burst error. To improve the performance further, a region of interest area detection is proposed that utilizes only the centre part of an image frame for LDPC decoding rather than using the whole area measurement. The LDPC codes are tested using an appropriate OCC packet structure, and its performance is compared with that of polar codes. The experimental results indicate that LDPC coding is more suitable in OCC systems. It is found that the proposed LDPC coding scheme not only recovers the data from burst errors but also enhances the transmission distance. In particular, soft‐decision LDPC decoding shows more resistance to burst errors and bit loss.