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Optimal design and effectiveness evaluation for inerter-based devices on mitigating seismic responses of base isolated structures

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Earthquake Engineering and Engineering Vibration 2021年第4期20卷 1021-1032页

作者： li yafeng li Shouying Chen Zhengqing Key Laboratory for Wind and Bridge Engineering of Hunan Province College of Civil EngineeringHunan UniversityChangsha 410082China

The optimal design and effectiveness of three control systems,tuned viscous mass damper(TVMD),tuned inerter damper(TID)and tuned mass damper(TMD),on mitigating the seismic responses of base isolated structures,were systematically ***,the seismic responses of the base isolated structure with each control system under white noise excitation were ***,the structural parameter optimizations of the TVMD,TID and TMD were conducted by using three different *** results show that the three control systems were all effective in minimizing the root mean square value of seismic responses,including the base shear of the BIS,the absolute acceleration of structural SDOF,and the relative displacement between the base isolation floor and the ***,considering the superstructure as a structural MDOF,a series of time history analyses were performed to investigate the effectiveness and activation sensitivity of the three control systems under far field and near fault seismic *** results show that the effectiveness of TID and TMD with optimized parameters on mitigating the seismic responses of base isolated structures increased as the mass ratio increases,and the effectiveness of TID was always better than TMD with the same mass *** TVMD with a lower mass ratio was more efficient in reducing the seismic response than the TID and ***,the TVMD,when compared with TMD and TID,had better activation sensitivity and a smaller stroke.

关键词： base isolated structure inerter optimal design seismic response vibration control

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Coupled dictionary learning method for image decomposition

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Science China(Information Sciences) 2013年第3期56卷 97-106页

作者： li yafeng FENG XiangChu Department of Applied Mathematics Xidian University Department of Computer Science Baoji University of Arts and Science

A novel variational model for image decomposition is *** a new cartoon-texture dictionary learning algorithm,which is guided by diffusion flow,is *** experiments show that the proposed method has better performance th... 详细信息

关键词： dictionary learning cartoon-texture decomposition image denoising total variation

Molecular packing tuning via chlorinated end group enables efficient binary organic solar cells over 18.5%

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Carbon Energy 2024年第3期6卷 196-203页

作者： yafeng li Zhenyu Chen Xingzheng Yan Ziyi Ge Zhejiang Business Technology Institute NingboZhejiangChina Zhejiang Engineering Research Center for Energy Optoelectronic Materials and Devices Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingboZhejiangChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina

Designing novel nonfullerene acceptors(NFAs)is of vital importance for the development of organic solar cells(OSC).Modification on the side chain and end group are two powerful tools to construct efficient ***,based on the high-performance L8BO,we selected 3-ethylheptyl to substitute the inner chain of 2-ethylhexyl,obtaining the backbone of *** we introduced different halogen atoms of fluorine and chlorine on 2-(3-oxo-2,3-dihydro-1Hinden-1-ylidene)malononitrile end group(EG)to construct efficient NFAs named BON3-F and BON3-Cl,*** donor D18 was chosen to combine with two novel NFAs to construct OSC ***,D18:BON3-Cl-based device shows a remarkable power conversion efficiency(PCE)of 18.57%,with a high open-circuit voltage(V_(OC))of 0.907 V and an excellent fill factor(FF)of 80.44%,which is one of the highest binary PCE of devices based on D18 as the ***,BON3-F-based device shows a relatively lower PCE of 17.79%with a decreased FF of 79.05%.The better photovoltaic performance is mainly attributed to the red-shifted absorption,higher electron and hole mobilities,reduced charge recombination,and enhanced molecular packing in the D18:BON3-Cl ***,we performed stability tests on two binary systems;the D18:BON3-Cl and D18:BON3-F devices maintain 88.1%and 85.5%of their initial efficiencies after 169 h of storage at 85°C in an N2-filled glove box,*** work demonstrates the importance of selecting halogen atoms on EG and provides an efficient binary system of D18:BON3-Cl for further improvement of PCE.

关键词： binary organic solar cell chlorinated end group molecular packing

Privacy preservation in permissionless blockchain:A survey

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Digital Communications and Networks 2021年第3期7卷 295-307页

作者： li Peng Wei Feng Zheng Yan yafeng li Xiaokang Zhou Shohei Shimizu School of Cyber Engineering Xidian UniversityXi’an710071China Department of Communications and Networking Aalto UniversityEspoo02150Finland The 20th Research Institute of China Electronics Technology Group Corporation Xi’an710061China Faculty of Data Science Shiga UniversityHikoneJapan RIKEN Center for Advanced Intelligence Project TokyoJapan

Permissionless blockchain,as a kind of distributed ledger,has gained considerable attention because of its openness,transparency,decentralization,and ***,permissionless blockchain has shown a good application prospect in many fields,from the initial cryptocurrency to the Internet of Things(IoT)and Vehicular Ad-Hoc Networking(VANET),which is considered as the beginning of rewriting our digital ***,blockchain confronts some privacy risks that hinder its practical *** numerous surveys reviewed the privacy preservation in blockchain,they failed to reveal the latest advances,nor have they been able to conduct a unified standard comprehensive classification of the privacy protection of permissionless ***,in this paper,we analyze the specific characteristics of permissionless blockchain,summarize the potential privacy threats,and investigate the unique privacy requirements of *** privacy preservation technologies are carefully surveyed and evaluated based on our proposed evaluation *** finally figure out open research issues as well as future research directions from the perspective of privacy issues.

关键词： Blockchain Privacy Cryptocurrency Anonymity

Blockchain-based data transmission control for Tactical Data link

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Digital Communications and Networks 2021年第3期7卷 285-294页

作者： Wei Feng yafeng li Xuetao Yang Zheng Yan liang Chen State Key Laboratory of Integrated Services Networks School of Cyber EngineeringXidian UniversityXi’an710071China The 20th Research Institute of China Electronics Technology Group Corporation Xi’an710061China Department of Communications and Networking Aalto UniversityEspoo02150Finland

Tactical Data link(TDL)is a communication system that utilizes a particular message format and a protocol to transmit data via wireless channels in an instant,automatic,and secure *** far,TDL has shown its excellence in military *** TDL adopts a distributed architecture to enhance anti-destruction ***,It still faces a problem of data inconsistency and thus cannot well support cooperation across multiple militarily *** tackle this problem,we propose to leverage blockchain to build an automatic and adaptive data transmission control scheme for *** achieves automatic data transmission and realizes information consistency among different TDL ***,applying smart contracts based on blockchain further enables adjusting data transmission policies *** analysis and experimental results based on simulations illustrate the effectiveness and efficiency of our proposed scheme.

关键词： Blockchain Tactical data link Consensus Data transmission control

Improved H_∞ filtering for Markov jumping linear systems with non-accessible mode information

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Science in China(Series F) 2009年第11期52卷 2180-2189页

作者： GUO yafeng li ShaoYuan Department of Automation Shanghai Jiao Tong University Shanghai 200240 China

This paper is concerned with the H∞ filtering problems for both continuous- and discrete-time Markov jumping linear systems （MJLS） with non-accessible mode information. A new design method is proposed, which greatly reduces the overdesign introduced in the derivation process. The desired filters can be obtained from the solution of convex optimization problems in terms of linear matrix inequalities （LMIs）, which can be solved via efficient interior-point algorithms. Numerical examples are provided to illustrate the advantages of the proposed approach.

关键词： Markov jumping linear systems H∞ filter mode-independent networked control system

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Dynamic parameter identification of upperlimb rehabilitation robot system based on variable parameter particle swarm optimisation

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IET Cyber-Systems and Robotics 2020年第3期2卷 140-148页

作者： Jin Lei Wang yafeng li Aimin An College of Electrical and Information Engineering Lanzhou University of TechnologyLanzhou 730050People's Republic of China Key Laboratory of Gansu Advanced Control for Industrial Processes Lanzhou 730050People's Republic of China National Demonstration Center for Experimental Electrical and Control Engineering Education Lanzhou University of TechnologyLanzhou 730050People's Republic of China

To solve the problem of uncertain parameters in dynamic modelling of upper-limb rehabilitation robots,a dynamic parameter identification method based on variable parameters particle swarm optimisation(PSO)is *** on the dynamic model of the system,the algorithm changes the inertia parameter and learning law of the basic PSO algorithm from the fixed-parameter to the function that changes with the number of *** solves the problems of small search space in the early stage and slow convergence speed in the later stage of the basic PSO algorithm,which greatly improves its identification ***,through the comparison and analysis of the simulation results,compared with those of the least square(LS)and unmodified PSO identification algorithms,a great improvement in the identification accuracy of the algorithm is *** control effect in the actual control system is also much better than those of the LS and PSO algorithms.

关键词： robot parameter system

A Simultaneous Cartoon-Texture Image Segmentation and Image Decomposition Method

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Chinese Journal of Electronics 2020年第5期29卷 906-915页

作者： li yafeng ZHAO Qijun ZHANG Wenbo FAN Pan ZHANG Renrui SUN Jieqi li Jing School of Computer Science and Technology Baoji University of Arts and Science College of Computer Science Sichuan University School of Information Science and Technology Tibet University School of Electronics Engineering and Computer Science Peking University

Image segmentation and image decomposition are fundamental problems in image *** decomposition methods for separating images into cartoon and texture components can effectively serve different image processing tasks because different components can be respectively treated in more effective way. However, image decomposition methods are currently simply taken as an independent preprocessing step, and particularly in image segmentation different effects of cartoon and texture components have not been *** paper presents a novel simultaneous cartoon-texture image segmentation and image decomposition method to boost the performance of both segmentation and decomposition. We design a fast alternating optimization algorithm to solve the proposed model. Experimental results demonstrate the outstanding performance of the proposed method on both image segmentation and image decomposition.

关键词： Image segmentation Image decomposition Variational model Dictionary learning

Robust Output Feedback Control for Fractional Order Nonlinear Systems with Time-varying Delays

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IEEE/CAA Journal of Automatica Sinica 2016年第4期3卷 477-482页

作者： Changchun Hua Tong Zhang yafeng li Xinping Guan Institute of Electrical Engineering Yanshan University Department of Automation Shanghai Jiao Tong University

Robust controller design problem is investigated for a class of fractional order nonlinear systems with time varying delays. Firstly, a reduced-order observer is designed. Then, an output feedback controller is designed. Both the designed observer and controller are independent of time delays. By choosing appropriate Lyapunov functions, we prove the designed controller can render the fractional order system asymptotically stable. A simulation example is given to verify the effectiveness of the proposed approach. © 2014 Chinese Association of Automation.

关键词： Algebra Backstepping Controllers Feedback Feedback control Lyapunov functions Nonlinear systems Robust control Time delay

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