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Long-range asymmetric Cherenkov radiation

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Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 170-171页

作者： Gang Zhong Qingdong ou Macao Institute of Materials Science and Engineering(MIMSE) Faculty of Innovation EngineeringMacao University of Science and TechnologyTaipaMacao 999078China

Cherenkov radiation(CR)is gaining increasing attention as a high-output power Terahertz radiation source,and it plays a significant role in particle detectors,accelerators,and space science[1].This captivating phenomenon was first observed by Cerenkov in 1934 and was later explained theoretically by Tamm and Frank in 1937,earning them the Nobel Prize in Physics in *** occurs when charged particles move faster than the phase velocity of light in a specific medium.

关键词： asymmetric faster explained

The low Mach number limit of non-isentropic magnetohydrodynamic equations with large temperature variations in bounded domains

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Science China Mathematics 2024年第4期67卷 787-818页

作者： Min Liang Yaobin ou School of Mathematics Renmin University of ChinaBeijing 100872China

This paper verifies the low Mach number limit of the non-isentropic compressible magnetohydrodynamic(MHD)equations with or without the magnetic diffusion in a three-dimensional bounded domain when the temperature variation is large but *** uniform estimates of strong solutions are established in a short time interval independent of the Mach number,provided that the slip boundary condition for the velocity and the Neumann boundary condition for the temperature are imposed and the initial data is well-prepared.

关键词： low Mach number limit non-isentropic compressible magnetohydrodynamic equations large temperature variations bounded domains

High-throughput screening of single-atom catalysts confined in monolayer black phosphorus for efficient nitrogen reduction reaction

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Nano Research 2024年第4期17卷 2360-2367页

作者： Xiao-Yan Li Manyi Duan Pengfei ou Department of Electrical and Computer Engineering University of TorontoTorontoOntario M5S 1A4Canada School of Physics and Electronic Engineering Sichuan Normal UniversityChengdu 610101China Department of Chemistry Northwestern UniversityEvanstonIL 60208USA

The discovery of metal-nitrogen centers as the active sites for electrolysis has aroused significant interest in utilizing single-atom catalysts for nitrogen reduction reaction(NRR).Properly designed nanostructured catalysts that strongly interact with nitrogen molecules(N_(2))can promote adsorption and activation,thereby resulting in efficient catalysts with high stability,activity,and *** this study,using density functional theory calculations,we selected monolayer black phosphorus(BP)as the substrate and screened a series of single-atom transition metals confined in tri-coordinated and tetra-coordinated active centers(without and with N dopants)to electro-catalyze *** a result,we have identified two promising candidates(Hf_(1)-N_(1)P_(2)-1 and Tc_(1)-N_(4)),which exhibit not only low overpotentials of 0.56 and 0.49 V but also high thermodynamic and electrochemical stability,as well as good selectivity towards NRR over the competing hydrogen evolution *** also demonstrate the ability of Hf_(1)-N_(1)P_(2)-1 and Tc_(1)-N_(4) to activate and hydrogenate N_(2) by donating electrons and regulating charge *** study not only predicts new BP-based promising catalysts but also provides guidance for the rational design of high-performance NRR electrocatalysts under ambient conditions.

关键词： N_(2) electroreduction reaction single-atom catalysts black phosphorus density functional theory high-throughput calculations

Block Basis for Modular Coinvariants of Pseudo-Reflection Groups

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Algebra Colloquium 2024年第1期31卷 41-48页

作者： Ke ou School of Statistics and Mathematics Yunnan University of Finance and Economics Kunming 650221China

We investigate the block basis for modular coinvariants of finite pseudo-reflection *** are particularly interested in the case of a subgroup G of the parabolic subgroups of GLn(q)which generalizes the Weyl groups of ... 详细信息

关键词： modular invariant theory pseudo-reflection group block basis coinvariant

Asymmetric time-varying integral barrier Lyapunov function based adaptive optimal control for nonlinear systems with dynamic state constraints

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Frontiers of Information Technology & Electronic Engineering 2024年第6期25卷 887-902页

作者： Yan WEI Mingshuang HAO Xinyi YU Linlin ou College of Information Engineering Zhejiang University of TechnologyHangzhou 310023China

This paper investigates the issue of adaptive optimal tracking control for nonlinear systems with dynamic state *** asymmetric time-varying integral barrier Lyapunov function(ATIBLF)based integral reinforcement learning(IRL)control algorithm with an actor–critic structure is first *** ATIBLF items are appropriately arranged in every step of the optimized backstepping control design to ensure that the dynamic full-state constraints are never ***,optimal virtual/actual control in every backstepping subsystem is decomposed with ATIBLF items and also with an adaptive optimized ***,neural networks are used to approximate the gradient value *** to the Lyapunov stability theorem,the boundedness of all signals of the closed-loop system is proved,and the proposed control scheme ensures that the system states are within predefined compact ***,the effectiveness of the proposed control approach is validated by simulations.

关键词： State constraints Asymmetric time-varying integral barrier Lyapunov function(ATIBLF) Adaptive optimal control Nonlinear systems

Pixel-level crack segmentation of tunnel lining segments based on an encoder–decoder network

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Frontiers of Structural and Civil Engineering 2024年第5期18卷 681-698页

作者： Shaokang Hou Zhigang ou Yuequn HUANG Yaoru LIU State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing 100084China China Renewable Energy Engineering Institute Beijing 100120China State Key Laboratory of Stimulation and Regulation of Water Cycles in River Basins China Institute of Water Resources and Hydropower ResearchBeijing 100038China Hunan Provincial Water Resources Development&Investment Co. Ltd.Changsha 410007China

Regular detection and repair for lining cracks are necessary to guarantee the safety and stability of *** development of computer vision has greatly promoted structural health *** study proposes a novel encoder–decoder structure,CrackRecNet,for semantic segmentation of lining segment cracks by integrating improved VGG-19 into the U-Net *** image acquisition equipment is designed based on a camera,3-dimensional printing(3DP)bracket and two laser rangefinders.A tunnel concrete structure crack(TCSC)image data set,containing images collected from a double-shield tunnel boring machines(TBM)tunnel in China,was *** data preprocessing operations,such as brightness adjustment,pixel resolution adjustment,flipping,splitting and annotation,2880 image samples with pixel resolution of 448×448 were *** model was implemented by Pytorch in PyCharm processed with 4 NVIDIA TITAN V *** the experiments,the proposed CrackRecNet showed better prediction performance than U-Net,TernausNet,and *** paper also discusses GPU parallel acceleration effect and the crack maximum width quantification.

关键词： tunnel lining segment crack detection semantic segmentation convolutional neural network encoder-decoder structure

Performance Prediction Based Workload Scheduling in Co-Located Cluster

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 2043-2067页

作者： Dongyang ou Yongjian Ren Congfeng Jiang School of Computer Science and Technology Hangzhou Dianzi UniversityHangzhou310018China

Cloud service providers generally co-locate online services and batch jobs onto the same computer cluster,where the resources can be pooled in order to maximize data center resource *** to resource competition between batch jobs and online services,co-location frequently impairs the performance of online *** study presents a quality of service(QoS)prediction-based schedulingmodel(QPSM)for *** performance prediction of QPSM consists of two parts:the prediction of an online service’s QoS anomaly based on XGBoost and the prediction of the completion time of an offline batch job based on ***-line service QoS anomaly prediction is used to evaluate the influence of batch jobmix on on-line service performance,and batch job completion time prediction is utilized to reduce the total waiting time of batch *** the same number of batch jobs are scheduled in experiments using typical test sets such as CloudSuite,the scheduling time required by QPSM is reduced by about 6 h on average compared with the first-come,first-served strategy and by about 11 h compared with the random scheduling *** with the non-co-located situation,QPSM can improve CPU resource utilization by 12.15% and memory resource utilization by 5.7% on *** show that the QPSM scheduling strategy proposed in this study can effectively guarantee the quality of online services and further improve cluster resource utilization.

关键词： Co-located cluster workload scheduling online service batch jobs data center

Side-Channel Leakage Analysis of Inner Product Masking

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Computers, Materials & Continua 2024年第4期79卷 1245-1262页

作者： Yuyuan Li Lang Li Yu ou College of Computer Science and Technology Hengyang Normal UniversityHengyang421002China Hunan Provincial Key Laboratory of Intelligent Information Processing and Application Hengyang Normal UniversityHengyang421002China

The Inner Product Masking(IPM)scheme has been shown to provide higher theoretical security guarantees than the BooleanMasking(BM).This scheme aims to increase the algebraic complexity of the coding to achieve a higher level of *** previous work unfolds when certain(adversarial and implementation)conditions are met,and we seek to complement these investigations by understanding what happens when these conditions deviate from their expected *** this paper,we investigate the security characteristics of IPM under different *** adversarial condition,the security properties of first-order IPMs obtained through parametric characterization are preserved in the face of univariate and bivariate *** implementation condition,we construct two new polynomial leakage functions to observe the nonlinear leakage of the IPM and connect the security order amplification to the nonlinear *** observe that the security of IPMis affected by the degree and the linear component in the leakage *** addition,the comparison experiments from the coefficients,signal-to-noise ratio(SNR)and the public parameter show that the security properties of the IPM are highly implementation-dependent.

关键词： Side-channel analysis inner product masking mutual information nonlinear leakage

Crowdsourcing RTK:a new GNSS positioning framework for building spatial high-resolution atmospheric maps based on massive vehicle GNSS data

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Satellite Navigation 2024年第1期5卷 91-108页

作者： Hongjin Xu Xingyu Chen Jikun ou Yunbin Yuan State Key Laboratory of Geodesy and Earth’s Dynamics Innovation Academy for Precision Measurement Science and Technology(APM)Chinese Academy of Sciences(CAS)Wuhan430071China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijingChina

High-quality spatial atmospheric delay correction information is essential for achieving fast integer ambiguity resolution(AR)in precise ***,traditional real-time precise positioning frameworks(i.e.,NRTK and PPP-RTK)depend on spatial low-resolution atmospheric delay correction through the expensive and sparsely distributed CORS *** results in limited public *** the mass production of autonomous driving vehicles,more cost-effective and widespread data sources can be explored to create spatial high-resolution atmospheric *** this study,we propose a new GNSS positioning framework that relies on dual base stations,massive vehicle GNSS data,and crowdsourced atmospheric delay correction maps(CAM).The map is easily produced and updated by vehicles equipped with GNSS receivers in a crowd-sourced ***,the map consists of between-station single-differenced ionospheric and tropospheric *** introduce the whole framework of CAM initialization for individual vehicles,on-cloud CAM maintenance,and CAM-augmented user-end *** map data are collected and preprocessed in ***,the crowdsourced data are uploaded to a cloud *** massive data from multiple vehicles are merged in the cloud to update the CAM in ***,the CAM will augment the user positioning *** framework forms a beneficial cycle where the CAM’s spatial resolution and the user positioning performance mutually improve each *** validate the performance of the proposed framework in real-world experiments and the applied potency at different spatial *** highlight that this framework is a reliable and practical positioning solution that meets the requirements of ubiquitous high-precision positioning.

关键词： New GNSS positioning framework Spatial high-resolution atmospheric delay correction Crowdsourced atmospheric delay correction maps Crowdsourced ionosphere Crowdsourced troposphere Ubiquitous