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Fault Analysis of Microgrids with Inverter Interfaced Resources in Grid-Connected and Islanded Modes

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Fault Analysis of Microgrids with Inverter Interfaced Resour...

On-Line Conference (ONCON), Industrial Electronics Society Annual

作者： Jigyesh Sharma Kushan Tharuka Lulbadda Anindita Golder Tarlochan Sidhu Sheldon S. Williamson Department of Electrical and Computer Engineering Advanced Storage Systems and Electric Transportation (ASSET) Laboratory Ontario Tech-Automotive Center of Excellence (ACE) Faculty of Engineering and Applied Science Smart Transportation Electrification and Energy Research (STEER) Group Ontario Tech University Oshawa ON Canada

The increasing penetration of inverter-based generation such as solar, wind and battery energy storage systems (BESS) has an impact on the fault currents in a microgrid. Also, if the microgrid is grid-connected or islanded affects the fault current. As such, it is important to conduct fault analysis of microgrids in grid-connected and islanded modes with different penetration levels of inverter-based generation sources to understand the impact of increasing levels of renewable energy on the fault currents. Different types of faults in a microgrid with inverter-based resources are simulated and the results are discussed and analyzed in this paper.

关键词： Wind energy generation Industrial electronics Renewable energy sources Wind energy Microgrids Inverters Batteries

2D Ge₂Se₂P₄ Monolayer: A Versatile Photocatalyst for Sustainable Water Splitting

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Journal of Physical Chemistry C 2024年第10期128卷 4245-4257页

作者： Vu, Tuan V. Hieu, Nguyen N. Vo, Dat D. Kartamyshev, A.I. Tong, Hien D. Trinh, Thuat T. Khuong Dien, Vo Haman, Zakaryae Dey, Poulumi Khossossi, Nabil Laboratory for Computational Physics Institute for Computational Science and Artificial Intelligence Van Lang University Ho Chi Minh City 70000 Viet Nam Faculty of Mechanical─Electrical and Computer Engineering School of Technology Van Lang University Ho Chi Minh City 70000 Viet Nam Institute of Research and Development Duy Tan University Da Nang 550000 Viet Nam Faculty of Natural Sciences Duy Tan University Da Nang 550000 Viet Nam Faculty of Engineering Vietnamese-German University Binh Duong 820000 Viet Nam Porelab Department of Chemistry Norwegian University of Science and Technology Høgskoleringen 5 Trondheim 7491 Norway Department of Physics National Cheng Kung University 1 University Road Tainan 70101 Taiwan Laboratoire de Physique des Matèriaux et Modélisations des Systèmes LP2MS Faculty of Sciences Department of Physics Moulay Ismail University Meknes 50050 Morocco Department of Materials Science and Engineering Faculty of Mechanical Engineering Delft University of Technology Mekelweg 2 Delft 2628 CD Netherlands

This study aims to identify photo-/electrocatalysts that can enhance the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR), which are of utmost importance in electro-/photochemical energy systems, such as solar energy, fuel cells, water electrolyzers, or metal-air batteries. Our study focused on investigating the 2D Ge₂Se₂P₄ monolayer and found that it exhibits a bifunctional photocatalyst with a very high solar-to-hydrogen efficiency. The two-dimensional (2D) Ge₂Se₂P₄ monolayer has superior HER activity compared to that of most 2D materials, and it also outperforms the reference catalysts IrO₂(110) and Pt(111) in terms of low overpotential values for ORR and OER mechanisms. Such superior catalytic performance in the 2D Ge₂Se₂P₄ monolayer can be attributed to its electron states, charge transfer process, and suitable band alignments referring to normal hydrogen electrodes. Overall, the study suggests that the Ge₂Se₂P₄ monolayer could be an excellent bifunctional catalyst for advancing photo-/electrochemical energy systems. © 2024 American Chemical Society.

关键词： Energy Evolution reactions Free energy Hydrogen Monolayers

Linear Quadratic Guidance Law for Joint Motion Planning of a Pursuer-Turret Assembly

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arXiv 2024年

作者： Jha, Bhargav Bopardikar, Shaunak D. Von Moll, Alexander Casbeer, David Michigan State University East LansingMI48864 United States Air Force Research Laboratory WPAFB OH45433 United States Department of Electrical and Computer Engineering Michigan State University United States Control Science Center 2210 8th St.

This paper presents joint motion planning of a vehicle with an attachedrotating turret. The turret has a limited range as well as the field of *** objective is capture a maneuvering target such that at the terminal time itis withing the field-of-view and range limits. Catering to it, we present aminimum effort guidance law that commensurate for the turn rate abilities ofthe vehicle and the turret. The guidance law is obtained using linearizationabout the collision triangle and admits an analytical solution. Simulationresults are presented to exemplify the cooperation between the turret and thevehicle. © 2024, CC BY.

关键词： Motion planning

Comment on "Amplified emission and lasing in photonic time crystals"

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arXiv 2022年

作者： Park, Jagang Park, Hee Chul Lee, Kyungmin Shin, Jonghwa Ryu, Jung-Wan Jeon, Wonju Park, Namkyoo Min, Bumki Department of Mechanical Engineering Korea Advanced Institute of Science and Technology Daejeon34141 Korea Republic of Daejeon34126 Korea Republic of Department of Physics Korea Advanced Institute of Science and Technology Daejeon34141 Korea Republic of Department of Material Sciences and Engineering Korea Advanced Institute of Science and Technology Daejeon34141 Korea Republic of Department of Electrical and Computer Engineering Seoul National University Seoul08826 Korea Republic of

Lyubarov et al. (Research Articles, 22 July 2022, p. 425) claim that the spontaneous emission rate of an atom vanishes at the momentum gap edges of photonic Floquet media. We show that their theoretical prediction is based on assumptions that result in misleading interpretations on the spontaneous emission rate in photonic Floquet media. © 2022, CC BY.

关键词： Spontaneous emission

A Dual-Objective Bandit-Based Opportunistic Band Selection Strategy for Hybrid-Band V2X Metaverse Content Update

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A Dual-Objective Bandit-Based Opportunistic Band Selection S...

IEEE Conference on Global Communications (GLOBECOM)

作者： Sherief Hashima Zubair Md Fadlullah Mostafa M. Fouda Kohei Hatano Eiji Takimoto Mohsen Guizani Computational Learning Theory Team RIKEN-AIP Fukuoka Japan Department of Computer Science Western University London ON Canada Department of Electrical and Computer Engineering Idaho State University Pocatello ID USA Center for Advanced Energy Studies (CAES) Idaho Falls ID USA Department of Informatics Kyushu University Fukuoka Japan Machine Learning Department Mohamed Bin Zayed University of Artificial Intelligence (MBZUAI) UAE

As vehicular communication networks embrace metaverse beyond 5G/6G systems, the rich content update via the least interfered subchannel of the optimal frequency band in a hybrid band vehicle to everything (V2X) setting emerges as a challenging optimization problem. We model this problem as a tradeoff between multi-band VR/AR devices attempting to perform metaverse scenes and environmental updates to metaverse roadside units (MRSUs) while minimizing energy consumption. Due to the computational hardness of this optimization, we formulate an opportunistic band selection problem using a multi-armed bandit (MAB) that provides a good quality solution in real-time without computationally burdening the already stretched augmented/virtual reality (AR/VR) units acting as transmitting nodes. The opportunistic use of scheduling rich content updates at traffic signals and stand-still scenarios maps well with the formulated bandit problem. We propose a Dual-Objective Minimax Optimal Stochastic Strategy (DOMOSS) as a natural solution to this problem. Through extensive computer-based simulations, we demonstrate the effectiveness of our proposal in contrast to baselines and comparable solutions. We also verify the quality of our solution and the convergence of the proposed strategy.

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Max-Min Beamformer for THz Wideband Communications

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Max-Min Beamformer for THz Wideband Communications

IEEE International Conference on Communications Workshops, ICC

作者： Boyu Ning Weidong Mei Lipeng Zhu Zhi Chen Rui Zhang National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of China (UESTC) Chengdu China Department of Electrical and Computer Engineering National University of Singapore The Chinese University of Hong Kong Shenzhen China Shenzhen Research Institute of Big Data Shenzhen China

Analog beamforming is appealing for future terahertz (THz) communications since it can generate high-gain directional beams with low-cost phase shifters. However, the conventional analog beamforming based on array response vector to steer a narrow beam may suffer from severe performance loss in wideband systems due to the “beam squint” effect over frequency. To tackle this issue, we propose a new max-min beamformer design in this paper for THz wideband communication systems, which aims to maximize the minimum beam gain over the entire frequency band. To solve this challenging problem, an augmented Lagrange method (ALM) is proposed to obtain a high-quality solution with low complexity. Numerical results show that the proposed beam design can yield considerably better performance than the conventional narrowband beamformer, especially in the case of large angle of departure (AoD) from the base station (BS) to the user.

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Prediction of severe preeclampsia in machine learning

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Medicine in Novel Technology and Devices 2022年第3期15卷 148-153页

作者： Xinyuan Zhang Yu Chen Stephen Salerno Yi Li Libin Zhou Xiaoxi Zeng Huafeng Li Department of Applied Mechanics College of Architecture and EnvironmentSichuan Province Biomechanical Engineering LaboratorySichuan UniversityChengdu610065SichuanChina Department of Biostatistics University of MichiganAnn ArborMIUSA Medical Big Data Center Sichuan UniversityChengdu610065SichuanChina Department of Computer Science University of WisconsinMadisonWIUSA West China Second University Hospital Sichuan UniversityChengdu610041China Department of Applied Mechanics Sichuan UniversityChengdu610065SichuanChina

This study aimed to find out the blood data characteristics of patients and explore the correlation between severe preeclampsia and blood index *** assistance for the early attention direction of severe preeclampsia diagnosis and treatment.19,653 pregnant women presenting to the West China Second University Hospital,Sichuan University from January 2017 to April *** screening,a total of 248 patients,124 severe preeclampsia cases,and 124 controls were selected for this ***-three blood examination variables were obtained from routine blood work,hepatic,renal and coagulation function *** gradient boosting machine(light GBM),decision tree and random forest were used for date *** randomly divided 35%of the original data as a testing set to conduct internal validation of the performance of the prediction *** area under receiver operating characteristic curve(AUC)was used as the main score to compare the three ***,a binary classification light GBM model based on aspartate aminotransferase,direct bilirubin and activated partial thromboplastin time ratio can predict severe preeclampsia with sensitivity of 88.37%,specificity of 77.27%,AUC of 89.74%and positive predictive value of 65.96%.We believe relevant quantifiable indicators can establish an effective prediction model,which can provide guidance for early detection and prevention of severe preeclampsia.

关键词： Preeclampsia Screening Prediction Blood examination Data characteristics

Federated Multi-armed Bandits Under Byzantine Attacks

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arXiv 2022年

作者： Saday, Artun Demirel, Ilker Yıldırım, Yigit Tekin, Cem Department of Electrical and Electronics Engineering Bilkent University Ankara06800 Turkey Computer Science & Artificial Intelligence Laboratory Massachusetts Institute of Technology CambridgeMA02139 United States

Multi-armed bandits (MAB) is a sequential decision-making model in which the learner controls the trade-off between exploration and exploitation to maximize its cumulative reward. Federated multi-armed bandits (FMAB) is an emerging framework where a cohort of learners with heterogeneous local models play a MAB game and communicate their aggregated feedback to a server to learn a globally optimal arm. Two key hurdles in FMAB are communication-efficient learning and resilience to adversarial attacks. To address these issues, we study the FMAB problem in the presence of Byzantine clients who can send false model updates threatening the learning process. We analyze the sample complexity and the regret of β-optimal arm identification. We borrow tools from robust statistics and propose a median-of-means (MoM)-based online algorithm, Fed-MoM-UCB, to cope with Byzantine clients. In particular, we show that if the Byzantine clients constitute less than half of the cohort, the cumulative regret with respect to β-optimal arms is bounded over time with high probability, showcasing both communication efficiency and Byzantine resilience. We analyze the interplay between the algorithm parameters, a discernibility margin, regret, communication cost, and the arms’ suboptimality gaps. We demonstrate Fed-MoM-UCB’s effectiveness against the baselines in the presence of Byzantine attacks via experiments. Copyright © 2022, The Authors. All rights reserved.

关键词： Federated learning

Learning Probabilistic Coordinate Fields for Robust Correspondences

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arXiv 2023年

作者： Zhao, Weiyue Lu, Hao Ye, Xinyi Cao, Zhiguo Li, Xin Key Laboratory of Image Processing and Intelligent Control Ministry of Education School of Artificial Intelligence and Automation Huazhong University of Science and Technology Wuhan430074 China The Lane Department of Computer Science and Electrical Engineering West Virginia University MorgantownWV26506-6109 United States

We introduce Probabilistic Coordinate Fields (PCFs), a novel geometric-invariant coordinate representation for image correspondence problems. In contrast to standard Cartesian coordinates, PCFs encode coordinates in correspondence-specific barycentric coordinate systems (BCS) with affine invariance. To know when and where to trust the encoded coordinates, we implement PCFs in a probabilistic network termed PCF-Net, which parameterizes the distribution of coordinate fields as Gaussian mixture models. By jointly optimizing coordinate fields and their confidence conditioned on dense flows, PCF-Net can work with various feature descriptors when quantifying the reliability of PCFs by confidence maps. An interesting observation of this work is that the learned confidence map converges to geometrically coherent and semantically consistent regions, which facilitates robust coordinate representation. By delivering the confident coordinates to keypoint/feature descriptors, we show that PCF-Net can be used as a plug-in to existing correspondence-dependent approaches. Extensive experiments on both indoor and outdoor datasets suggest that accurate geometric invariant coordinates help to achieve the state of the art in several correspondence problems, such as sparse feature matching, dense image registration, camera pose estimation, and consistency filtering. Further, the interpretable confidence map predicted by PCF-Net can also be leveraged to other novel applications from texture transfer to multi-homography classification. Copyright © 2023, The Authors. All rights reserved.

关键词： Textures