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Ideals in the Roe Algebras of Discrete Metric Spaces with Coefficients in B(H)

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Chinese Annals of Mathematics,Series B 2009年第2期30卷 139-144页

作者： yingjie HU Qin wang Department of Applied Mathematics Donghua University Shanghai 201620 China

The notion of an ideal family of weighted subspaces of a discrete metric space X with bounded geometry is introduced. It is shown that, if X has Yu’s property A, the ideal structure of the Roe algebra of X with coefficients in B(H) is completely characterized by the ideal families of weighted subspaces of X, where B(H) denotes the C*-algebra of bounded linear operators on a separable Hilbert space H.

关键词： Roe algebra Ideal Metric space Coarse geometry Band-dominatedoperator

In-plane dynamics of a fluid-conveying corrugated pipe supported at both ends

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Applied Mathematics and Mechanics(English Edition) 2019年第8期40卷 1119-1134页

作者： yingjie wang Qichang ZHANG Wei wang Tianzhi YANG Tianjin Key Laboratory of Nonlinear Dynamics and Control Department of MechanicsSchool of Mechanical EngineeringTianjin University

The dynamics and stability of fluid-conveying corrugated pipes are investigated. The flow velocity is assumed to harmonically vary along the pipe rather than with time. The dimensionless equation is discretized with the differential quadrature method (DQM). Subsequently, the effects of the mean flow velocity and two key parameters of the corrugated pipe, i.e., the amplitude of the corrugations and the total number of the corrugations, are studied. The results show that the corrugated pipe will lose stability by flutter even if it has been supported at both ends. When the total number of the corrugations is sufficient, this flutter instability occurs at a micro flow velocity. These phenomena are verified via the Runge-Kutta method. The critical flow velocity of divergence is analyzed in detail. Compared with uniform pipes, the critical velocity will be reduced due to the corrugations, thus accelerating the divergence instability. Specifically, the critical flow velocity decreases if the amplitude of the corrugations increases. However, the critical flow velocity cannot be monotonously reduced with the increase in the total number of the corrugations. An extreme point appears, which can be used to realize the parameter optimization of corrugated pipes in practical applications.

关键词： fluid-structure interaction fluid-conveying corrugated pipe differential quadrature method (DQM) bifurcation flutter

Multi-Objective Task Assignment for Maximizing Social Welfare in Spatio-Temporal Crowdsourcing

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China Communications 2021年第11期18卷 11-25页

作者： Shengnan Wu yingjie wang Xiangrong Tong School of Computer and Control Engineering Yantai UniversityYantai 264005China

With the development of the Internet of Things(IoT),spatio-temporal crowdsourcing(mobile crowdsourcing)has become an emerging paradigm for addressing location-based sensing ***,the delay caused by network transmission has led to low data processing ***,edge computing can solve this problem,effectively reduce the delay of data transmission,and improve data processing capacity,so that the crowdsourcing platform can make better decisions ***,this paper combines spatio-temporal crowdsourcing and edge computing to study the Multi-Objective Optimization Task Assignment(MOO-TA)problem in the edge computing *** proposed online incentive mechanism considers the task difficulty attribute to motivate crowd workers to perform sensing tasks in the unpopular *** this paper,the Weighted and Multi-Objective Particle Swarm Combination(WAMOPSC)algorithm is proposed to maximize both platform’s and crowd workers’utility,so as to maximize social *** algorithm combines the traditional Linear Weighted Summation(LWS)algorithm and Multi-Objective Particle Swarm Optimization(MOPSO)algorithm to find pareto optimal solutions of multi-objective optimization task assignment problem as much as possible for crowdsourcing platform to *** comparison experiments on real data sets,the effectiveness and feasibility of the proposed method are evaluated.

关键词： spatio-temporal crowdsourcing edge computing task assignment multi-objective optimization particle swarm optimization Pareto optimal solution

Improved Simulation of Summer Heavy Rainfall over Beijing and Henan by the YHGSM with Updated Subgrid Orographic Parameters

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Journal of Meteorological Research 2024年第3期38卷 504-529页

作者： yingjie wang Jianping WU Kaijun REN College of Computer Science and Technology National University of Defense TechnologyChangsha410600China College of Meteorology and Oceanography National University of Defense TechnologyChangsha410600China

In numerical weather prediction(NWP),the parameterization of orographic drag plays an important role in representing subgrid orographic *** subgrid orographic parameters are the key input to the parameterization of orographic ***,the subgrid orographic parameters in most NWP models were produced based on elevation datasets generated many years ago,with a coarse resolution and low *** this paper,using the latest high-quality elevation data and considering the applicable scale range of the subgrid orographic parameters,we construct the orographic parameters,including the subgrid orographic standard deviation,anisotropy,orientation,and slope,that are required as input to the orographic gravity wave drag(OGWD)***,we introduce the newly constructed orographic parameters into the Yin-He Global Spectral Model(YHGSM),optimize the description of the orographic effect in the model,and improve the simulation of two typical heavy rainfall events in Beijing and Henan.

关键词： subgrid orographic parameters orographic drag heavy rainfall Yin-He Global Spectral Model(YHGSM) parameterization

Predicting the probability distribution of Martian rocks mechanical property based on microscale rock mechanical experiments and accurate grain-based modeling

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International Journal of Mining Science and Technology 2024年第9期34卷 1327-1339页

作者： Shuohui Yin yingjie wang Jingang Liu Engineering Research Center of Complex Tracks Processing Technology and Equipment of Ministry of Education Xiangtan UniversityXiangtan 411105China School of Mechanical Engineering and Mechanics Xiangtan UniversityXiangtan 411105China

The exploration of Mars would heavily rely on Martian rocks mechanics and engineering *** the mechanical property of Martian rocks is uncertain,it is of utmost importance to predict the probability distribution of Martian rocks mechanical property for the success of Mars *** this paper,a fast and accurate probability distribution method for predicting the macroscale elastic modulus of Martian rocks was proposed by integrating the microscale rock mechanical experiments(micro-RME),accurate grain-based modeling(AGBM)and upscaling methods based on reliability ***,the microstructure of NWA12564 Martian sample and elastic modulus of each mineral were obtained by micro-RME with TESCAN integrated mineral analyzer(TIMA)and *** best probability distribution function of the minerals was determined by Kolmogorov-Smirnov(K-S)***,based on best distribution function of each mineral,the Monte Carlo simulations(MCS)and upscaling methods were implemented to obtain the probability distribution of upscaled elastic ***,the correlation between the upscaled elastic modulus and macroscale elastic modulus obtained by AGBM was *** accurate probability distribution of the macroscale elastic modulus was obtained by this correlation *** proposed method can predict the probability distribution of Martian rocks mechanical property with any size and shape samples.

关键词： Probability distribution Martian rocks Microscale rock mechanic experiment Nanoindentation Accurate grain-based modeling

Load-dependent Variable Gearing Mechanism of Muscle-like Soft Actuator

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Journal of Bionic Engineering 2022年第1期19卷 29-43页

作者： yingjie wang Chunbao Liu Luquan Ren Lei Ren School of Mechanical and Aerospace Engineering Jilin UniversityChangchun130022China Key Laboratory of Bionic Engineering Ministry of EducationJilin UniversityChangchun130022China School of Mechanical Aerospace and Civil EngineeringUniversity of ManchesterManchesterM139PLUK

Pennate muscle is characterized by muscle fibers that are oriented at a certain angle(pennation angle)relative to the muscle’s line of action and rotation during *** fiber rotation amplifies the shortening velocity of muscle,to match loading conditions without any control *** unique variable gearing mechanism,which characterized by Architecture Gear Ratio(AGR),is involves complex interaction among three key elements:muscle fibers,connective tissue,and the pennation ***,how three elements determine the AGR of muscle-like actuator is still *** study introduces a Himisk actuator that arranges five contractile units at a certain pennation angle in a flexible matrix,the experiment and simulation results demonstrated that the proposed actuator could vary AGR automatically in response to variable loading *** on this actuator,we present a series of actuators by simulations with the varying pennation angle(P),elastic modulus of the flexible matrix(E),and number of contractile units(N)to analyze their effects on AGR,and their interaction by three-factor analysis of *** results demonstrated that P and N effect on the AGR significantly,while E effects on AGR slightly,which supported the idea that the P is the essential factor for the AGR,and N is also an important factor due to the capability of force *** provides a better understanding of mechanical behavior and an effective optimizing strategy to muscle-like soft actuator.

关键词： Bioinspired Actuator Pennate muscle Gearing mechanism

Bioinspired soft actuators with highly ordered skeletal muscle structures

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Bio-Design and Manufacturing 2022年第1期5卷 174-188页

作者： yingjie wang Chunbao Liu Luquan Ren Lei Ren School of Mechanical and Aerospace Engineering Jilin UniversityChangchun 130022China School of Mechanical Aerospace and Civil EngineeringUniversity of ManchesterManchester M139PLUK Key Laboratory of Bionic Engineering Ministry of EducationJilin UniversityChangchun 130022China

Mammals such as humans develop skeletal muscles composed of muscle fibers and connective tissue,which have mechanical properties that enable power output with three-dimensional motion when *** muscle-like actuators developed to date,such as the McKibben artificial muscle,often focus sole contractile elements and have rarely addressed the contribution of flexible connective tissue that forms an integral part of the structure and morphology of biological ***,we present a class of pneumatic muscle-like actuators,termed highly mimetic skeletal muscle(HimiSK)actuator,that consist of parallelly arranged contractile units in a flexible matrix inspired by ultrasonic measurements on skeletal *** contractile units act as a muscle fiber to produce active shortening force,and the flexible matrix functions as connective tissue to generate passive *** application of positive pressure to the contractile units can produce a linear contraction and *** this actuator,we assign different flexible materials as contractile units and a flexible matrix,thus forming five mold *** actuators feature three-dimensional motion on activation and present both intrinsic force-velocity and force-length characteristics that closely resebmle those of a biological *** output and tetanic force produced by harder contractile units improve the maximum output force by up to about 41.3%and the tetanic force by up to about 168%.Moreover,high displacement and velocity can be generated by a softer flexible matrix,with the improvement of maximum displacement up to about 33.3%and velocity up to about 73%.The results demonstrate that contractile units play a crucial role in force generation,while the flexible matrix has a significant impact on force transmission and deformation;the final force,velocity,displacement,and three-dimensional motion results from the interplay of contractile units,fluid and flexible *** approach introduces a m

关键词： Bioinspired Soft robotics Actuator Skeletal muscle

Multi-stage online task assignment driven by offline data under spatio-temporal crowdsourcing

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Digital Communications and Networks 2022年第4期8卷 516-530页

作者： Qi Zhang yingjie wang Zhipeng Cai Xiangrong Tong The School of Computer and Control Engineering Yantai UniversityYantai264005China Yantai Key Laboratory of High-end Ocean Engineering Equipment and Intelligent Technology Yantai264005China The Department of Computer Science Georgia State UniversityAtlantaGA30303USA

In the era of the Internet of Things(IoT),the crowdsourcing process is driven by data collected by devices that interact with each other and with the physical *** a part of the IoT ecosystem,task assignment has become an important goal of the research *** task assignment algorithms can be categorized as offline(performs better with datasets but struggles to achieve good real-life results)or online(works well with real-life input but is difficult to optimize regarding in-depth assignments).This paper proposes a Cross-regional Online Task(CROT)assignment problem based on the online assignment *** the CROT problem,an Online Task Assignment across Regions based on Prediction(OTARP)algorithm is *** is a two-stage graphics-driven bilateral assignment strategy that uses edge cloud and graph embedding to complete task *** first stage uses historical data to make offline predictions,with a graph-driven method for offline bipartite graph *** second stage uses a bipartite graph to complete the online task assignment *** paper proposes accelerating the task assignment process through multiple assignment rounds and optimizing the process by combining offline guidance and online assignment *** encourage crowd workers to complete crowd tasks across regions,an incentive strategy is designed to encourage crowd workers’*** avoid the idle problem in the process of crowd worker movement,a drop-by-rider problem is used to help crowd workers accept more crowd tasks,optimize the number of assignments,and increase ***,through comparison experiments on real datasets,the performance of the proposed algorithm on crowd worker utility value and the matching number is evaluated.

关键词： Spatiotemporal crowdsourcing Cross-regional Edge cloud Offline prediction Oline task assignment

A Review of Biological Fluid Power Systems and Their Potential Bionic Applications

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Journal of Bionic Engineering 2019年第3期16卷 367-399页

作者： Chunbao Liu yingjie wang Luquan Ren Lei Ren School of Mechanical and Aerospace Engineering Jilin University Changchun 130022 China Key Laboratory of Bionic Engineering Ministry of Education Jilin University Changchun 130022 China School of Mechanical Aerospace and Civil Engineering University of Manchester Manchester M13 9PL UK

Nature has always inspired human achievements in industry, and biomimetics is increasingly being applied in fluid power technology. Arachnida use hydraulic forces, rather than muscle, for leg extensions during locomotion. Many cold-blooded and soft-bodied organisms rely on a hydrostatic skeleton to transmit force, which involves a hydraulic mechanism. Biological hydraulic transmission differs from engineering hydraulic transmission in many aspects, such as in energy transfer and transformation, the movement mode, environmental friendliness, system pressure level, and energy supplement mode. The existence of a hydraulic mechanism in a biological drive requires 3 features: a power source, cavity, and working medium. The power source is similar to a hydraulic pump, and the cavity is similar to a hydraulic cylinder, both of which are necessary for producing deformation. The working medium is similar to a hydraulic fluid. Under these 3 conditions, a biological flow is generated inside or outside the body to meet the requirements of a biological drive. This paper reviews the biological organisms that employ hydraulic systems, identifies related studies on these biological hydraulic systems, and summarizes the mechanisms involved in using hydraulic pressure to achieve graceful and agile movements. This in-depth study and exploration of biological hydraulic systems can provide a good reference for solving the challenges of using hydraulic systems, such as increasing the energy efficiency, improving reliability, building smart components and systems, reducing the size and weight of components, reducing the environmental impact of systems, and improving and applying energy storage and redeployment capabilities. This paper also includes a detailed discussion of new ideas and innovative sources for the future development of hydraulic systems. In contrast with the bio-inspired designs used in other engineering fields, very few studies have reported on using bio-inspired methods

关键词： bionic fluid power pressurized liquids locomotion bio-inspired applications