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A Second-Order Semi-Implicit Method for the Inertial Landau-Lifshitz-Gilbert Equation

Numerical Mathematics(Theory,Methods and Applications) 2023年第1期16卷 182-203页

作者： Panchi Li Lei Yang Jin Lan Rui Du Jingrun Chen School of Mathematical Sciences Soochow UniversitySuzhou 215006China School of Computer Science and Engineering Macao University of Science and TechnologyMacao SARChina Center for Joint Quantum Studies and Department of Physics School of ScienceTianjin University92 Weijin RoadTianjin 300072China Mathematical Center for Interdisciplinary Research Soochow UniversitySuzhou 215006China Suzhou Institute for Advanced Research University of Science and Technology of ChinaSuzhouJiangsu 215123China School of Mathematical Sciences University of Science and Technology of ChinaHefeiAnhui 230026China

Electron spins in magnetic materials have preferred orientations collectively and generate the macroscopic *** dynamics spans over a wide range of timescales from femtosecond to picosecond,and then to *** Landau-Lifshitz-Gilbert(LLG)equation has been widely used in micromagnetics simulations over *** theoretical and experimental advances have shown that the inertia of magnetization emerges at sub-picosecond timescales and contributes significantly to the ultrafast magnetization dynamics,which cannot be captured intrinsically by the LLG ***,as a generalization,the inertial LLG(iLLG)equation is proposed to model the ultrafast magnetization ***,the LLG equation is a nonlinear system of parabolic type with(possible)***,the iLLG equation is a nonlinear system of mixed hyperbolic-parabolic type with degeneracy,and exhibits more complicated *** behaves as a hyperbolic system at sub-picosecond timescales,while behaves as a parabolic system at larger timescales spanning from picosecond to *** hybrid behaviors impose additional difficulties on designing efficient numerical methods for the iLLG *** this work,we propose a second-order semiimplicit scheme to solve the iLLG *** second-order temporal derivative of magnetization is approximated by the standard centered difference scheme,and the first-order temporal derivative is approximated by the midpoint scheme involving three time *** nonlinear terms are treated semi-implicitly using one-sided interpolation with second-order *** each time step,the unconditionally unique solvability of the unsymmetric linear system is proved with detailed discussions on the condition ***,the second-order accuracy of the proposed method in both time and space is *** sub-picosecond timescales,the inertial effect of ferromagnetics is observed in micromagnetics simulations,in consistency wi

关键词： Inertial Landau-Lifshitz-Gilbert equation semi-implicit scheme second-order accuracy micromagnetics simulations

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An Overview of Artificial Intelligence Ethics

IEEE Transactions on Artificial Intelligence

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IEEE Transactions on Artificial Intelligence 2023年第4期4卷 799-819页

作者： Huang, Changwu Zhang, Zeqi Mao, Bifei Yao, Xin Southern University of Science and Technology Research Institute of Trustworthy Autonomous Systems Shenzhen518055 China Southern University of Science and Technology Department of Computer Science and Engineering Guangdong Provincial Key Laboratory of Brain-inspired Intelligent Computation Shenzhen518055 China Huawei Technologies Company Ltd. Trustworthiness Theory Research Center Shenzhen518055 China University of Birmingham School of Computer Science BirminghamB15 2TT United Kingdom

Artificial intelligence (AI) has profoundly changed and will continue to change our lives. AI is being applied in more and more fields and scenarios such as autonomous driving, medical care, media, finance, industrial robots, and internet services. The widespread application of AI and its deep integration with the economy and society have improved efficiency and produced benefits. At the same time, it will inevitably impact the existing social order and raise ethical concerns. Ethical issues, such as privacy leakage, discrimination, unemployment, and security risks, brought about by AI systems have caused great trouble to people. Therefore, AI ethics, which is a field related to the study of ethical issues in AI, has become not only an important research topic in academia, but also an important topic of common concern for individuals, organizations, countries, and society. This article will give a comprehensive overview of this field by summarizing and analyzing the ethical risks and issues raised by AI, ethical guidelines and principles issued by different organizations, approaches for addressing ethical issues in AI, and methods for evaluating the ethics of AI. Additionally, challenges in implementing ethics in AI and some future perspectives are pointed out. We hope our work will provide a systematic and comprehensive overview of AI ethics for researchers and practitioners in this field, especially the beginners of this research discipline. © 2020 IEEE.

关键词： Industrial robots

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Front-running Attacks in Hash-Based Transaction Sharding Blockchains 23

Front-running Attacks in Hash-Based Transaction Sharding Blo...

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23rd IEEE International Conference on Trust, Security and Privacy in Computing and Communications, TrustCom 2024

作者： Wang, Yusen Lou, Jiong Wang, Zihan Li, Jie Shanghai Jiao Tong University Department of Computer Science and Engineering China Blockchain Advanced Research Center China Shanghai Key Laboratory of Trusted Data Circulation and Governance and Web3 China

Sharding is one of the prominent solutions to solve the scalability problem of traditional blockchains. By dividing the blockchain network into independent shards, transactions in different shards can be executed in parallel, improving the throughput of the blockchain. However, sharding also brings security issues. In a hash-based transaction sharding system, the output shard of a transaction is determined by the hash value of the transaction. Unfortunately, we show that this hashbased transaction assignment strategy can be easily exploited by attackers to conduct front-running attacks. Attackers can take advantage of the execution differences between different shards and the extra processing time of cross-shard transactions to make the attacker's transaction executed and committed before the victim's transaction, thereby obtaining the benefits that originally belonged to the victim. We also propose a flooding front-running attack, which introduces a single-shard flooding attack to enhance the front-running attack. Specifically, injecting a large number of junk transactions into the shard where the victim's transaction is located can significantly extend the execution time of the victim's transaction. We demonstrate the feasibility and practical effects of these two attacks through experiments on RapidChain, which show that a single-shard flooding attack can increase the success rate of a front-running attack by 12%. Finally, we discuss two possible mitigation measures and the cost of two proposed attacks. © 2024 IEEE.

关键词： blockchain flooding attack front-running attack sharding

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Ferroelectric Enhancement in a TiN/Hf1-xZrxO2/W Device with Controlled Oxidation of the Bottom Electrode

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ACS Applied Electronic Materials 2024年第2期6卷 1078-1086页

作者： Chiniwar, Santosh P. Hsieh, Ya-Chen Shih, Ching-Hsiang Teng, Chih-Yu Yang, Jheng-Lin Hu, Chenming Lin, Bi-Hsuan Tang, Mau-Tsu Tseng, Yuan-Chieh Department of Material Science & Engineering National Yang Ming Chiao Tung University Hsinchu30010 Taiwan International College of Semiconductor Technology National Yang Ming Chiao Tung University Hsinchu30010 Taiwan Department of Electrical Engineering and Computer Sciences University of California BerkeleyCA94720 United States National Synchrotron Radiation Research Center Hsinchu30076 Taiwan

Hf1-xZxO2 (HZO) is a promising ferroelectric (FE) material with CMOS compatibility, while the TiN/HZO/W metal-ferroelectric-metal structure provides balanced thermal expansion for stacking. In this study, we developed a 7 nm film of HZO with a FE polarization (2Pr) value of ∼43 μC/cm2 and cycling endurance of 108 by determining the appropriate oxidation state for a W bottom electrode deposited via atomic layer deposition with a relatively low annealing temperature of 400 °C. To visualize FE uniformity, we used X-ray absorption spectroscopy phase mapping to construct a two-dimensional map of the orthorhombic (O), tetragonal (T), and monoclinic (M) phases of the HZO film. Subsequent orientation- and chemical-state-resolved X-ray analysis revealed that the enhanced FE polarization performance can be attributed to the combined effects of interface strain and oxygen vacancies. Piezoelectric force microscopy verified the switching uniformity of the devices and revealed the electrical characteristics for use in device optimization. © 2024 The Authors. Published by American Chemical Society

关键词： X ray diffraction analysis

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Digital Communications and Networks

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Digital Communications and Networks 2022年第3期8卷 235-236页

作者： Ruidong Li Shiwen Mao Periklis Chatzimisios Constandinos X.Mavromoustakis Intelligent computation and network laboratory(ICNL)at Kanazawa University Japan the Wireless Engineering Research and Education Center(WEREC) Department of Information and Electronic Engineering at the International Hellenic University(Greece) Constandinos X.Mavromoustakis is currently a Professor at the Department of Computer Science at the University of Nicosia Cyprus

Guest editorial The emerging applications,suchas Augmented and Virtual Realities(AR/VR),InternetofThings(IoT),4K/8Kstreaming,raisestrongrequirementsto movecomputationfrom thecloudtotheedgestobecloser *** are tremendous possibilities for the network edge,which may includeavariety ofentities,such as small datacenters,end devices,and resource-abundant network *** together provide the network computation and intelligence to users.

关键词： network IoT Communications

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AlGaN-Based Deep-Ultraviolet Light-Emitting Diodes With Varied Thickness of Sidewall Passivation via Atomic Layer Deposition

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IEEE Transactions on Electron Devices 2023年第11期70卷 5727-5731页

作者： Peng, Kangwei Lai, Shouqiang Shen, Mengchun Li, Saijun Zheng, Lijie Dai, Yurong Chen, Jilan Zhu, Lihong Chen, Guolong Wang, Shuli Kuo, Hao-Chun Lu, Yijun Chen, Zhong Wu, Tingzhu Xiamen University Fujian Engineering Research Center for Solid-State Lighting Department of Electronic Science Xiamen361005 China Sanan Optoelectronics Company Ltd. Xiamen361005 China National Yang Ming Chiao Tung University College of Electrical and Computer Engineering Department of Photonics and Graduate Institute of Electro-Optical Engineering Hsinchu30010 Taiwan Hon Hai Research Institute Semiconductor Research Center Taipei11492 Taiwan Xiamen361005 China

In this study, we fabricated deep-ultraviolet light-emitting diodes (DUV-LEDs) with Al2O3 films of 0-, 130-, and 255-nm via atomic layer deposition (ALD). In addition, the effects of the passivation layers on the DUV-LEDs were systematically investigated. The current-voltage characteristics of these samples revealed the passivating effect of the Al2O3 ALD films on the DUV-LEDs. By analyzing the external quantum efficiency (EQE) at room temperature using the ABC + f,(n) model, the differences in the physical mechanisms of the Al2O3 ALD film on DUV-LEDs were determined. The measurements of the electroluminescence (EL) and far-field radiation patterns (EQE, light output power (LOP), and radiation patterns) showed that ALD can enhance the performance of DUV-LEDs, particularly DUV-LEDs with a 130-nm Al2O3 ALD passivation layer. Moreover, the aging test and failure ratio of these DUV-LEDs under humidity exposure (85 °C/85% RH) indicated the specific effect of these Al2O3 ALD films on the reliability of DUV-LEDs. © 1963-2012 IEEE.

关键词： Light emitting diodes

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A New Flow-Based Approach for Enhancing Botnet Detection Efficiency Using Convolutional Neural Networks and Long Short-Term Memory

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Knowledge and Information Systems 2025年第7期67卷 6139-6170页

作者： Asadi, Mehdi Heidari, Arash Jafari Navimipour, Nima Department of Computer Engineering Islamic Azad University Khameneh Branch Khameneh Iran Department of Software Engineering Haliç University Istanbul Turkey Department of Computer Engineering Faculty of Engineering and Natural Science İstanbul Atlas University Istanbul Turkey Department of Computer Science and Engineering Qatar University Doha Qatar Department of Computer Engineering Faculty of Engineering and Natural Sciences Kadir Has University Istanbul Turkey Future Technology Research Center National Yunlin University of Science and Technology Douliou Taiwan Research Center of High Technologies and Innovative Engineering Western Caspian University Baku Azerbaijan

Despite the growing research and development of botnet detection tools, an ever-increasing spread of botnets and their victims is being witnessed. Due to the frequent adaptation of botnets to evolving responses offered by host-based and network-based detection mechanisms, traditional methods are found to lack adequate defense against botnet threats. In this regard, the suggestion is made to employ flow-based detection methods and conduct behavioral analysis of network traffic. To enhance the performance of these approaches, this paper proposes utilizing a hybrid deep learning method that combines convolutional neural network (CNN) and long short-term memory (LSTM) methods. CNN efficiently extracts spatial features from network traffic, such as patterns in flow characteristics, while LSTM captures temporal dependencies critical to detecting sequential patterns in botnet behaviors. Experimental results reveal the effectiveness of the proposed CNN-LSTM method in classifying botnet traffic. In comparison with the results obtained by the leading method on the identical dataset, the proposed approach showcased noteworthy enhancements, including a 0.61% increase in precision, a 0.03% augmentation in accuracy, a 0.42% enhancement in the recall, a 0.51% improvement in the F1-score, and a 0.10% reduction in the false-positive rate. Moreover, the utilization of the CNN-LSTM framework exhibited robust overall performance and notable expeditiousness in the realm of botnet traffic identification. Additionally, we conducted an evaluation concerning the impact of three widely recognized adversarial attacks on the Information Security Centre of Excellence dataset and the Information Security and Object Technology dataset. The findings underscored the proposed method’s propensity for delivering a promising performance in the face of these adversarial challenges.

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Temperature Effects on Microalgae Cell Growth in an Outdoor HLTP 2nd

Temperature Effects on Microalgae Cell Growth in an Outdo...

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2nd International Conference on Mathematical Analysis and Applications in Modeling, ICMAAM 2023

作者： Nahar, Nurun Monir, Mohammad Iftekhar Islam, Md. Rashedul Deb, Ujjwal Kumar Department of Mathematics Chittagong University of Engineering and Technology Chattogram Bangladesh Department of Mathematics Premier University Chattogram Bangladesh Jamal Nazrul Islam Research Center for Mathematical and Physical Sciences University of Chittagong Chittagong Bangladesh Department of Computer Science and Engineering International Islamic University Chittagong Chattogram Bangladesh

ISBN: (纸本)9789819791934

Biofuel from microalgae is a promising alternative that can substitute fossil fuels because they are renewable and eco-friendly. The growth of microalgae is influenced by numerous culture parameters, and temperature is considered one of the vital growth factors among them. In this study, we developed a computational growth model related to irradiance related temperature for an outdoor operated Horizontal Loop Tubular Photobioreactor (HLTP) for a specific geographic location. The effects of direct and diffuse solar radiation on the Photobioreactor (PBR) temperature are considered in this model. The meteorological data associated with the geographic location has been collected for the simulation. We simulated the model by COMSOL Multiphysics and ob-served a temperature fluctuation between 24.85 ∘C and 38.45 ∘C throughout the PBR domain. The significant issue of temperature control is also suggested from this study. Over the simulated period, a uniform cell growth has been observed. The hydrodynamic behaviors of the suspension flow inside the reactor, radial and axial temperature distribution are also analyzed in this study. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.

关键词： Microalgae

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Twenty-one days of bed rest alter motor unit properties and neuromuscular junction transmission in young adults

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Journal of Applied Physiology 2025年第6期138卷 1411-1424页

作者： Sarto, Fabio Kalc, Miloš Motanova, Evgeniia S. Franchi, Martino V. Stashuk, Daniel Murks, Nina Valli, Giacomo Negro, Samuele Prašnikar, Tomaž Gasparini, Mladen Martino, Giovanni De Vito, Giuseppe Holobar, Aleš Simunič, Boštjan Pišot, Rado Narici, Marco V. Department of Biomedical Sciences University of Padova Padova Italy Centre of Studies and Activities for Space "Giuseppe Colombo Padova Italy Science and Research Center Koper Institute for Kinesiology Research Koper Slovenia CIR-MYO Myology Center University of Padova Padova Italy Department of Systems Design Engineering University of Waterloo Waterloo ON Canada Faculty of Electrical Engineering and Computer Science University of Maribor Maribor Slovenia Department of Clinical and Experimental Sciences University of Brescia Brescia Italy Izola General Hospital Izola Slovenia

Previous studies showed that properties of higher-threshold motor units (MUs) and neuromuscular junction (NMJ) function are preserved during short-term disuse. This study aimed to test how a longer disuse period affects MU properties, NMJ transmission, and NMJ morphology remodeling. Nine young healthy males (age: 18-29 yr) underwent 21 days of horizontal bed rest. Pre- (BR0) and postbed rest (BR21), quadriceps maximal voluntary contraction (MVC), and size were assessed. We combined intramuscular electromyography (iEMG) and high-density surface electromyography (HDsEMG) recordings on the vastus lateralis to assess MU properties at 25% and 50% of MVC. Muscle biopsies and blood samples were also collected. Quadriceps MVC and size decreased at BR21. We found alterations in MU properties at both contraction intensities, including reduced discharge rate, MU potential area changes, and increased complexity. NMJ transmission was found to be reduced at BR21 at 25% MVC. This functional NMJ impairment was biochemically corroborated by an increase in serum C-terminal agrin fragment concentration, a biomarker of NMJ instability. In addition, a direct assessment of NMJ morphology revealed the presence of some denervated NMJs exclusively at BR21. In conclusion, 21-day bed rest altered MU properties across different contraction intensities and impaired NMJ transmission with initial signs of remodeling/denervation. Disuse duration appears to be a critical factor, as previous shorter studies failed to detect some of these changes. We believe these findings are clinically relevant for disuse after trauma, surgery, or illness and may support the development of effective *** & NOTEWORTHY Leveraging both intramuscular and high-density surface EMG recordings in the vastus lateralis, we identified alterations in motor unit (MU) properties in young adults after 21 days of bed rest. These included reduced discharge rates and changes in MU potential size and complexity, observ

关键词： disuse electromyography electrophysiology physical inactivity unloading

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Receding-Horizon Trajectory Planning for Under-Actuated Autonomous Vehicles Based on Collaborative Neurodynamic Optimization

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IEEE/CAA Journal of Automatica Sinica 2022年第11期9卷 1909-1923页

作者： Jiasen Wang Jun Wang Qing-Long Han IEEE the Future Network Research Center Purple Mountain LaboratoriesNanjing 211111China the Department of Computer Science the School of Data ScienceCity University of Hong KongHong KongChina the School of Science Computing and Engineering TechnologiesSwinburne University of TechnologyMelbourne VIC 3122Australia

This paper addresses a major issue in planning the trajectories of under-actuated autonomous vehicles based on neurodynamic optimization.A receding-horizon vehicle trajectory planning task is formulated as a sequential global optimization problem with weighted quadratic navigation functions and obstacle avoidance constraints based on given vehicle goal *** feasibility of the formulated optimization problem is guaranteed under derived *** optimization problem is sequentially solved via collaborative neurodynamic optimization in a neurodynamics-driven trajectory planning method/*** results with under-actuated unmanned wheeled vehicles and autonomous surface vehicles are elaborated to substantiate the efficacy of the neurodynamics-driven trajectory planning method.

关键词： Collaborative neurodynamic optimization receding-horizon planning trajectory planning under-actuated vehicles

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