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Kinetic scale magnetic holes in the terrestrial magnetosheath:A review

Science China Earth Sciences 2024年第9期67卷 2739-2771页

作者： Quanqi SHI Shutao YAO Maria HAMRIN ji LIU Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment Institute of Space SciencesShandong UniversityWeihai 264209China Department of Physics UmeåUniversityUmeå90746Sweden Department of Physics University of AlbertaEdmonton T6K 2P6Canada

Magnetic holes at the ion-to-electron kinetic scale(KSMHs)are one of the extremely small intermittent structures generated in turbulent magnetized *** recent years,the explorations of KSMHs have made substantial strides,driven by the ultra-high-precision observational data gathered from the Magnetospheric Multiscale(MMS)*** review paper summarizes the up-to-date characteristics of the KSMHs observed in Earth’s turbulent magnetosheath,as well as their potential impacts on space *** review starts by introducing the fundamental properties of the KSMHs,including observational features,particle behaviors,scales,geometries,and distributions in terrestrial *** have discovered that KSMHs display a quasi-circular electron vortex-like structure attributed to electron diamagnetic *** electrons exhibit noticeable non-gyrotropy and undergo *** occurrence rate of KSMH in the Earth’s magnetosheath is significantly greater than in the solar wind and magnetotail,suggesting the turbulent magnetosheath is a primary source ***,KSMHs have also been generated in turbulence simulations and successfully reproduced by the kinetic equilibrium ***,KSMHs have demonstrated their ability to accelerate electrons by a novel non-adiabatic electron acceleration mechanism,serve as an additional avenue for energy dissipation during magnetic reconnection,and generate diverse wave phenomena,including whistler waves,electrostatic solitary waves,and electron cyclotron waves in space *** results highlight the magnetic hole’s impact such as wave-particle interaction,energy cascade/dissipation,and particle acceleration/heating in space *** end this paper by summarizing these discoveries,discussing the generation mechanism,similar structures,and observations in the Earth’s magnetotail and solar wind,and presenting a future extension perspective in this active field.

关键词： Magnetic hole Magnetic dip/cavity Electron vortex Magnetosheath Turbulence Coherent structure Mirror mode Kinetic scale Electron acceleration Whistler

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Machine learning model based on non-convex penalized huberized-SVM

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Journal of Electronic Science and Technology 2024年第1期22卷 81-94页

作者： Peng Wang ji Guo Lin-Feng Li School of Finance and Economics Xizang Minzu UniversityXianyang712082China Research Center for Quality Development of Xizang Special Industries Xianyang712082China School of Computer Science and Technology Xinjiang UniversityUrumqi830017China

The support vector machine(SVM)is a classical machine learning *** the hinge loss and least absolute shrinkage and selection operator(LASSO)penalty are usually used in traditional ***,the hinge loss is not differentiable,and the LASSO penalty does not have the Oracle *** this paper,the huberized loss is combined with non-convex penalties to obtain a model that has the advantages of both the computational simplicity and the Oracle property,contributing to higher accuracy than traditional *** is experimentally demonstrated that the two non-convex huberized-SVM methods,smoothly clipped absolute deviation huberized-SVM(SCAD-HSVM)and minimax concave penalty huberized-SVM(MCP-HSVM),outperform the traditional SVM method in terms of the prediction accuracy and classifier *** are also superior in terms of variable selection,especially when there is a high linear correlation between the *** they are applied to the prediction of listed companies,the variables that can affect and predict financial distress are accurately filtered *** all the indicators,the indicators per share have the greatest influence while those of solvency have the weakest *** companies can assess the financial situation with the indicators screened by our algorithm and make an early warning of their possible financial distress in advance with higher precision.

关键词： Huberized loss Machine learning Non-convex penalties Support vector machine(SVM)

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The neuroscience of pain,addiction,and anesthesia

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Zoological Research 2024年第3期45卷 709-710页

作者： ji Hu Ping Zheng School of Life Science and Technology ShanghaiTech UniversityShanghai 201210China State Key Laboratory of Medical Neurobiology Institutes of Brain ScienceMOE Frontier Center for Brain ScienceDepartment of Neurology of Zhongshan HospitalFudan UniversityShanghai 200032China

Researchers and clinicians have long been interested in the mechanisms of pain,anesthesia,and *** International Association for the Study of Pain(IASP)defines pain as an unpleasant sensory and emotional experience associated with,or resembling that associated with,actual or potential tissue damage(Raja et al.,2020).Drug addiction refers to a condition of reliance that develops from regular drug consumption,which may lead to withdrawal symptoms when use is *** involves the complete loss of consciousness induced by an inhaled or intravenous anesthetic(Tosello et al.,2022).In this special collection,Zoological Research presents research findings focused on pain,addiction,and anesthesia.

关键词： anesthesia damage

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A 16-bit 18-MSPS flash-assisted SAR ADC with hybrid synchronous and asynchronous control logic

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Journal of Semiconductors 2024年第6期45卷 3-12页

作者： Junyao ji Xinao ji Ziyu Zhou Zhichao Dai Xuhui Chen jie Zhang Zheng jiang Hong Zhang School of Microelectronics Xi'an Jiaotong UniversityXi'an 710049China Qingdao Hi-image Tech.Co.Ltd. Qingdao 266100China

This paper presents a 16-bit,18-MSPS(million samples per second)flash-assisted successive-approximation-register(SAR)analog-to-digital converter(ADC)utilizing hybrid synchronous and asynchronous(HYSAS)timing control logic based on an on-chip delay-locked loop(DLL).The HYSAS scheme can provide a longer settling time for the capacitive digital-to-analog converter(CDAC)than the synchronous and asynchronous SAR ***,the issue of incomplete settling or ringing in the DAC voltage for cases of either on-chip or off-chip reference voltage can be solved to a large *** addition,the fore-ground calibration of the CDAC’s mismatch is performed with a finite-impulse-response bandpass filter(FIR-BPF)based least-mean-square(LMS)algorithm in an off-chip FPGA(field programmable gate array).Fabricated in 40-nm CMOS process,the proto-type ADC achieves 94.02-dB spurious-free dynamic range(SFDR),and 75.98-dB signal-to-noise-and-distortion ratio(SNDR)for a 2.88-MHz input under 18-MSPS sampling rate.

关键词： SAR ADC control logic reference ringing DAC incomplete settling

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Identifying and localizing of seismogenic electromagnetic anomalies from data observed by permanent MT stations

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Science China Earth Sciences 2024年第5期67卷 1698-1713页

作者： Bing HAN Wenbao HU Guoze ZHAO ji TANG State Key Laboratory of Earthquake Dynamics Institute of GeologyBeijing 100029China Key Laboratory of Exploration Technologies for Oil and Gas Resources of Ministry of Education Yangtze UniversityWuhan 430100China

In this research, an arbitrarily oriented electric dipole at subsurface is used to simulate Seismogenic Electromagnetic(SEM) radiation emanating from a seismic zone during its gestation phase. Analytical synthesis of responses at the Lijiang magnetotelluric(MT) station has revealed that SEM radiation could induce identifiable anomalies in the electromagnetic(EM)spectrum, apparent resistivity and phase within specific frequency bands. Background variations were extracted from long-term observation data of Dali and Lijiang MT stations, enabling the identification of SEM anomalies related to the Yunlong and Yangbi earthquakes. Multiple parameters of dipole sources at subsurface were obtained by applying the Differential Ant Colony Optimization(DACO) algorithm to anomalous data of two stations with multi-frequencies and various response functions. The spatial distribution of these predicted dipoles is predominantly clustered in or around the seismogenic area, with their azimuthal orientation aligning towards the seismogenic fault in general. This study has demonstrated the potential of using subsurface electric dipole simulations for SEM radiation analysis, offering a feasible approach for the prediction and understanding of seismogenic zones.

关键词： MT responses Identifying SEM anomaly Vector electric dipole responses Localizing SEM sources by inversion

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Threshold Selection and Resource Allocation for Quantized Identification

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Journal of Systems Science & Complexity 2024年第1期37卷 204-229页

作者： WANG Ying LI Xin ZHAO Yanlong ZHANG ji-Feng Key Laboratory of Systems and Control Institute of Systems ScienceAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

This paper is concerned with the optimal threshold selection and resource allocation problems of quantized identification, whose aims are improving identification efficiency under limited resources. Firstly, the first-order asymptotically optimal quantized identification theory is extended to the weak persistent excitation condition. Secondly, the characteristics of time and space complexities are established based on the Cramér-Rao lower bound of quantized systems. On these basis, the optimal selection methods of fixed thresholds and adaptive thresholds are established under aperiodic signals, which answer how to achieve the best efficiency of quantized identification under the same time and space complexity. In addition, based on the principle of maximizing the identification efficiency under a given resource, the optimal resource allocation methods of quantized identification are given for the cases of fixed thresholds and adaptive thresholds, respectively, which show how to balance time and space complexity to realize the best identification efficiency of quantized identification.

关键词： Quantized output resource allocation system identification threshold selection.

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Index-free triangle-based graph local clustering

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Frontiers of Computer Science 2024年第3期18卷 143-153页

作者： Zhe YUAN Zhewei WEI Fangrui LV ji-Rong WEN The Country and Area Studies Academy Beijing Foreign Studies UniversityBeijing 100089China Gaoling School of Artificial Intelligence Renmin University of ChinaBeijing 100872China

Motif-based graph local clustering(MGLC)is a popular method for graph mining tasks due to its various ***,the traditional two-phase approach of precomputing motif weights before performing local clustering loses locality and is impractical for large *** some attempts have been made to address the efficiency bottleneck,there is still no applicable algorithm for large scale graphs with billions of *** this paper,we propose a purely local and index-free method called Index-free Triangle-based Graph Local Clustering(TGLC^(*))to solve the MGLC problem w.r.t.a ***^(*)directly estimates the Personalized PageRank(PPR)vector using random walks with the desired triangleweighted distribution and proposes the clustering result using a standard sweep *** demonstrate TGLC^(*)’s scalability through theoretical analysis and its practical benefits through a novel visualization ***^(*)is the first algorithm to solve the MGLC problem without precomputing the motif *** experiments on seven real-world large-scale datasets show that TGLC^(*)is applicable and scalable for large graphs.

关键词： graph local clustering triangle motif index-free sampling method visualization

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Cell Mechanics Regulates the Dynamic Anisotropic Remodeling of Fibril Matrix at Large Scale

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Research 2024年第3期2023卷 401-415页

作者： Mingxing Ouyang Yanling Hu Weihui Chen Hui Li Yingbo ji Linshuo Qiu Linlin Zhu Baohua ji Bing Bu Linhong Deng Institute of Biomedical Engineering and Health Sciences School of Medical and Health Engineering and School of PharmacyChangzhou UniversityChangzhou213164China Institute of Biomechanics and Applications Department of Engineering MechanicsZhejang UniversityHangzhou310027China.

Living tissues often have anisotropic and heterogeneous organizations, in which developmental processes are coordinated by cells and extracellular matrix modeling. Cells have the capability of modeling matrix in long distance;however, the biophysical mechanism is largely unknown. We investigated the dynamic remodeling of collagen I (COL) fibril matrix by cell contraction with designed patterns of cell clusters. By considering cell dynamic contractions, our molecular dynamics simulations predicted the anisotropic patterns of the observed COL bundling in experiments with various geometrical patterns without spatial limitation. The pattern of COL bundling was closely related to the dynamic remodeling of fibril under cell active contraction. We showed that cell cytoskeletal integrity (actin filaments and microtubules), actomyosin contractions, and endoplasmic reticulum calcium channels acting as force generations and transductions were essential for fiber bundling inductions, and membrane mechanosensory components integrin and Piezo played critical roles as well. This study revealed the underlying mechanisms of the cell mechanics-induced matrix remodeling in large scales and the associated cellular mechanism and should provide important guidelines for tissue engineering in potential biomedical applications.

关键词： contraction Dynamic Matrix

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Adaptive joint configuration optimization for collaborative inference in edge-cloud systems

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Science China(Information Sciences) 2024年第4期67卷 335-336页

作者： Zheming YANG Wen ji Zhi WANG Institute of Computing Technology Chinese Academy of Sciences University of Chinese Academy of Sciences Peng Cheng Laboratory Tsinghua Shenzhen International Graduate School Tsinghua University

With the rapid development of technologies such as deep learning and the Internet of Things(IoT), the deployment and application of various IoT devices are becoming increasingly widespread, resulting in the inference tasks generated increasing dramatically [1]. Many deep neural network(DNN) models are deployed on servers for performing inference tasks.

关键词： Inference engines

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Fuzzy-Model-Based Finite Frequency Fault Detection Filtering Design for Two-Dimensional Nonlinear Systems

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IEEE/CAA Journal of Automatica Sinica 2024年第10期11卷 2099-2110页

作者： Meng Wang Huaicheng Yan jianbin Qiu Wenqiang ji Key Laboratory of Smart Manufacturing in Energy Chemical Process Ministry of EducationSchool of Information Science and EngineeringEast China University of Science and TechnologyShanghai 200237China Research Institute of Intelligent Control and Systems School of AstronauticsHarbin Institute of TechnologyHarbin 150080China School of Artificial Intelligence Hebei University of TechnologyTianjin 300401China IEEE

This article studies the fault detection filtering design problem for Roesser type two-dimensional(2-D)nonlinear systems described by uncertain 2-D Takagi-Sugeno(T-S)fuzzy ***,fuzzy Lyapunov functions are constructed and the 2-D Fourier transform is exploited,based on which a finite frequency fault detection filtering design method is proposed such that a residual signal is generated with robustness to external disturbances and sensitivity to *** has been shown that the utilization of available frequency spectrum information of faults and disturbances makes the proposed filtering design method more general and less conservative compared with a conventional nonfrequency based filtering design ***,with the proposed evaluation function and its threshold,a novel mixed finite frequency H_(∞)/H_(-)fault detection algorithm is developed,based on which the fault can be immediately detected once the evaluation function exceeds the ***,it is verified with simulation studies that the proposed method is effective and less conservative than conventional non-frequency and/or common Lyapunov function based filtering design methods.

关键词： Fault diagnosis finite frequency specifications mixed H_(∞)/H_(-)performance two-dimensional nonlinear systems

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