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Natural gait analysis for a biped robot: jogging ***

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Science China(Information Sciences) 2019年第12期62卷 272-276页

作者： Uzair KHAN zhiyong chen School of Electrical Engineering and Computing University of NewcastleCallaghan

Dear editor,Humans have long been looking in animal locomotion for inspiration to solve their complex design problems. Numerous control strategies mimic simple biological processes. Feedback control is one such exampl... 详细信息

关键词： spring jogging vs.walking Natural gait analysis for a biped robot

Twinning behavior of an extruded Mg-Gd-Y-Zn-Zr alloy sheet under tension and compression

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Journal of Rare Earths 2024年第12期42卷 2208-2216,I0001页

作者： Jianfen Huang Tao chen Wugui Jiang Longhui Mao zhiyong chen Key Laboratory for Microstructural Control of Metallic Materials of Jiangxi Province(Nanchang Hangkong University) Nanchang330063China School of Aeronautical Manufacturing Engineering Nanchang Hangkong UniversityNanchang330063China School of Materials Science and Engineering Central South UniversityChangsha410083China

In this study,twinning behaviors of an extruded Mg-4.7Gd-3.4Y-1.2Zn-0.5Zr(wt%)alloy sheet along different directions extrusion direction(ED),45°:45°to ED and transverse direction(TD)under tension and compression were *** results show that:(i)the twinning frequency of the extruded alloy sheet along different directions shows obvious anisotropy under both tension and compression while demonstrating opposite orders of ED>45°>TD under tension and TD>45°>ED under *** anisotropic twinning frequencies are both in accord with their average twinning Schmid factor(TSF)orders.(ii)Under both tension and compression,the twinning variants(TVs)with the highest and the second highest TSF are frequently selected with ***,the TV selection law under tension has a certain difference from that of compression,which should be related to the TSF distributions of ortho-TV,meta-TV and para-TV under tension and compression.

关键词： Magnesium alloy Texture Twinning behavior Anisotropy Rare earths

STRAIN-DEPENDENCE OF PLASTIC STRAIN RATIO OF DEEP-DRAWING ALUMINIUM-KILLED STEEL SHEET

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Transactions of Nonferrous Metals Society of China 1996年第1期6卷 95-99页

作者： Li Saiyi Zhang Xinming chen zhiyong Department of Materials Science and Engineering Central South University of Technology Changsha 410083

The change of width and length of an aluminium-killed(AK)steel sheet was measured in detail at various tensile strain *** effects of tensile strain on the conventional strain ratio,rc-value,and the instantaneous strain ratio,r^(1)-value,were *** was shown that the strain ratio of the AK steel sheet had obvious *** individual r^(c)-values for all tested directions tended to unity with increasing strain so that the planar anisotropy decreased with increasing *** r^(1)-value had overall straidenpendency similar to that of r^(c)-value,though it was overly sensitive to the experimental errors and showed significant variation with *** the representation of average strain *** linear regression strain ratio,r^(r)-value,which was obtained by fitting a straight line to the εw vs εt curve,is preferable to the r^(c)-value measured at some specfic extension.

关键词： plastic strain ratio anisotropy tension

An Energy Efficient Design for UAV Communication With Mobile Edge Computing

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China Communications 2019年第1期16卷 26-36页

作者： Lingyan Fan Wu Yan Xihan chen zhiyong chen Qingjiang Shi Deparment of Communication Engineering Hangzhou Dianzi University College of ISEE Zhejiang University Deparment of Communication Engineering Zhejiang Sci-Tech University School of Software Engineering Tongji University

This paper considers a UAV communication system with mobile edge computing(MEC).We minimize the energy consumption of the whole system via jointly optimizing the UAV's trajectory and task assignment as well as CPU's computational speed under the set of resource *** this end,we first derive the energy consumption model of data processing,and then obtain the energy consumption model of fixed-wing UAV's *** optimization problem is mathematically *** address the problem,we first obtain the approximate optimization problem by applying the technique of discrete linear state-space approximation,and then transform the non-convex constraints into convex by using ***,a concave-convex procedure(CCCP) based algorithm is proposed in order to solve the optimization problem *** results show the efficacy of the proposed algorithm.

关键词： mobile edge computing(MEC) UAV communication concave-convex procedure(CCCP) energy minimization

Joint Optimization of Communications and Computing Resources Allocation for Deterministic Transmission in Wireless Edge Networks

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China Communications 2022年第5期19卷 1-11页

作者： Lanjing chen zhiyong chen Bin Xia Xin Jiang Feng Hu School of Electronic Information and Electrical Engineering Shanghai Jiao Tong UniversityShanghai 200240China China Mobile Industry Research Institute Shanghai 201206China

Motivated by 5th generation wireless systems(5G),a large number of emerging applications appear,which put forward higher requirements for the task’s transmission determinacy,which refers to the delay and *** satisfy the deterministic requirement,mobile edge computing(MEC)is envisioned as a promising technique for reducing the end-to-end delay *** this paper,we consider delaysensitive task and jitter-sensitive task,and then formulate the joint communications and computing optimization problem under the latency,the total bandwidth,the total transmission power of base station(BS)and the computing ability of the MEC server constraints to minimize the delay and jitter in a multiuser MEC *** of the problems are nonconvex,we decouple them into some subproblems and propose the corresponding algorithms to obtain a suboptimal ***,numerical results show that the proposed algorithms have a significant performance gain over the traditional solution in terms of the delay and the jitter.

关键词： mobile edge computing deterministic transmission delay and jitter resource allocation

How often should one update control and estimation:review of networked triggering techniques

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Science China(Information Sciences) 2020年第5期63卷 6-23页

作者： zhiyong chen Qing-Long HAN Yamin YAN Zheng-Guang WU School of Electrical Engineering and Computing University of Newcastle School of Software and Electrical Engineering Swinburne University of Technology Institute of Cyber-Systems and Control Zhejiang University

Management of resources is a constant topic in industrial systems. How to use minimum communication resources is of particular interest for control and estimation of networked systems. It raises the question for researchers in the field: how often should one update control and estimation? One of the most intelligent approaches is to trigger updates by events. In the literature, event-triggered control and estimation have been widely studied in the last decade. On one hand, events should be triggered sufficiently frequent to maintain system performance; on the other hand, the possibility of Zeno behavior caused by infinite frequency should be avoided. This review aims at revisiting some existing triggering techniques in a unified formulation, separated from system dynamics and control and estimation strategies. It brings readers better understanding of triggering mechanisms, the underlying technical challenges, and some promising future research topics.

关键词： event-triggered control event-triggered estimation networked systems Zeno behavior

Formation of nanocrystalline AZ31B Mg alloys via cryogenic rotary swaging

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Journal of Magnesium and Alloys 2023年第5期11卷 1580-1591页

作者： Xin chen Chuming Liu Yingchun Wan Shunong Jiang Xiuzhu Han zhiyong chen Light Alloy Research Institute Central South UniversityChangsha 410083China School of Materials Science and Engineering Central South UniversityChangsha 410083China School of Metallurgy and Environment Central South UniversityChangsha 410083China Beijing Institute of Spacecraft System Engineering Beijing 100094China

A bulk nanocrystalline AZ31B Mg alloy with extraordinarily high strength was prepared via cryogenic rotary swaging in this *** obtained alloy shows finer grains,higher strength,and a negligible tension-compression yield asymmetry,compared with that prepared via room-temperature rotary *** electron microscopy investigations showed that at the initial stage,multiple twins,mostly tension twins,were activated and intersected with each other,thereby refining the coarse grains into a fine lamellar ***,two types of nanoscale subgrains were generated with increasing swaging *** first type of nanoscale subgrain contained twin boundaries and low-angle grain *** type of subgrain appeared at the twin-twin intersections and was mainly driven by high local *** second type of nanoscale subgrain was formed within the twin *** boundaries of this type of subgrain did not contain twin boundaries and were transformed from massive dislocation ***,randomly oriented nanograins were obtained via dynamic recrystallization,under the combined function of deformation heat and increased stored *** with room-temperature rotary swaging,cryogenic rotary swaging exhibits a slower grain refinement process but a remarkably enhanced grain refinement effect after the same five-pass swaging.

关键词： Cryogenic rotary swaging Nanocrystalline Mg alloy Grain refinement Twinning Dislocation arrays

Functional monodisperse microspheres fabricated by solvothermal precipitation co-polymerization

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Chinese Journal of Chemical Engineering 2021年第6期34卷 323-331页

作者： Fenghao Guo Yuanyuan Ding Yanyan Wang Xiao Gao zhiyong chen Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials School of Chemistry and Chemical EngineeringUniversity of JinanJinan 250022China

Simultaneous achievement in high solid content and high microsphere yield is deemed a challenge in the fabrication of monodisperse microspheres by precipitation *** herein demonstrate that micro-sized monodisperse poly(methacrylic monomer-divinylbenzene)microspheres containing epoxy,lauyl,carboxyl and hydroxyl functions can be fabricated by solvothermal precipitation copolymerization at 20%(mass)monomer loading with over 94%microsphere *** morphology and porosity of the obtained particles can be readily tuned by cosolvent-acetonitrile binary *** of a small amount of cosolvent that has similar solubility parameter to that of the functional monomer can significantly improve the monodispersity of the obtained *** tetrahydrofuran was used as the co-solvent,the surface area of the highly porous microspheres achieved higher than 400 m^(2)·g^(-1).Solvothermal precipitation co-polymerization can be expected in scale-up fabrication of various monodisperse functional microspheres free of any surfactant and additive.

关键词： Monodisperse microsphere Solvothermal Methacrylic monomer Precipitation polymerization Core-shell structure

Task assignment for social-oriented crowdsourcing

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Frontiers of Computer Science 2021年第2期15卷 39-49页

作者： Gang WU zhiyong chen Jia LIU Donghong HAN Baiyou QIAO School of Computer Science and Engineering Northeastern UniversityShenyang110004China State Key Laboratory for Novel Software Technology Nanjing UniversityNanjing210023China

Crowdsourcing has become an efficient measure to solve machine-hard problems by embracing group wisdom,in which tasks are disseminated and assigned to a group of workers in the way of open *** social relationships formed during this process may in turn contribute to the completion of future *** this sense,it is necessary to take social factors into consideration in the research of ***,there is little work on the interactions between social relationships and crowdsourcing *** this paper,we propose to study such interactions in those social-oriented crowdsourcing systems from the perspective of task assignment.A prototype system is built to help users publish,assign,accept,and accomplish location-based crowdsourcing tasks as well as promoting the development and utilization of social relationships during the ***,in order to exploit the potential relationships between crowdsourcing workers and tasks,we propose a“worker-task”accuracy estimation algorithm based on a graph model that joints the factorized matrixes of both the user social networks and the history“worker-task”*** the worker-task accuracy estimation matrix,a group of optimal worker candidates is efficiently chosen for a task,and a greedy task assignment algorithm is proposed to further the matching of worker-task pairs among multiple crowdsourcing tasks so as to maximize the overall *** with the similarity based task assignment algorithm,experimental results show that the average recommendation success rate increased by 3.67%;the average task completion rate increased by 6.17%;the number of new friends added per week increased from 7.4 to 10.5;and the average task acceptance time decreased by 8.5 seconds.

关键词： crowdsourcing social networks task assignment