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Acta Mechanica Sinica 2011年第2期27卷 200-207页

作者： Ling Li Ming-shun yuan State Key Laboratory of Hydroscience and Engineering Tsinghua University 100084 Beijing China

In this paper the effects of hydrophobic wall on skin-friction drag in the channel flow are investigated through large eddy simulation on the basis of weaklycompressible flow equations with the MacCormack’s scheme on collocated mesh in the FVM framework. The slip length model is adopted to describe the behavior of the slip velocities in the streamwise and spanwise directions at the interface between the hydrophobic wall and turbulent channel flow. Simulation results are presented by analyzing flow behaviors over hydrophobic wall with the Smagorinky subgrid-scale model and a dynamic model on computational meshes of different resolutions. Comparison and analysis are made on the distributions of timeaveraged velocity, velocity fluctuations, Reynolds stress as well as the skin-friction drag. Excellent agreement between the present study and previous results demonstrates the accuracy of the simple classical second-order scheme in representing turbulent vertox near hydrophobic wall. In addition, the relation of drag reduction efficiency versus time-averaged slip velocity is established. It is also foundthat the decrease of velocity gradient in the close wall region is responsible for the drag reduction. Considering its advantages of high calculation precision and efficiency, the present method has good prospect in its application to practical projects.

关键词： Wall turbulences · Large eddy simulation · Drag reduction · Hydrophobic wall · Weakly compressible flow

Improved lazy theta algorithm based on octree map for path planning of UAV

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Defence Technology（防务技术） 2023年第5期23卷 8-18页

作者： Meng-shun yuan Tong-le Zhou Mou Chen College of Automation Engineering Nanjing University of Aeronautics and AstronauticsNanjing211106China

This paper investigates the path planning method of unmanned aerial vehicle(UAV)in threedimensional ***,in order to keep a safe distance between UAV and obstacles,the obstacle grid in the map is *** using the data structure of octree,the octree map is constructed,and the search nodes is significantly ***,the lazy theta*algorithm,including neighbor node search,line-of-sight algorithm and heuristics weight adjustment is *** the process of node search,UAV constraint conditions are considered to ensure the planned path is actually *** redundant nodes are reduced by the line-of-sight algorithm through judging whether visible between two *** weight adjustment strategy is employed to control the precision and speed of ***,the simulation results show that the improved lazy theta*algorithm is suitable for path planning of UAV in complex environment with *** effectiveness and flight ability of the algorithm are verified by comparing experiments and real flight.

关键词： Unmanned aerial vehicle Path planning Lazy theta*algorithm Octree map Line-of-sight algorithm

Strong Consistency of the Empirical Martingale Simulation Option Price Estimator

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Acta Mathematicae Applicatae Sinica 2009年第3期25卷 355-368页

作者： Zhu-shun yuan Ge-mai Chen Department of Mathematics and Statistics University of Calgary 2500 University Drive NW Calgary Alberta Canada T2N 1N4

A simulation technique known as empirical martingale simulation （EMS） was proposed to improve simulation accuracy. By an adjustment to the standard Monte Carlo simulation, EMS ensures that the simulated price satisfies the rational option pricing bounds and that the estimated derivative contract price is strongly consistent with payoffs that satisfy Lipschitz condition. However, for some currently used contracts such as self-quanto options and asymmetric or symmetric power options, it is open whether the above asymptotic result holds. In this paper, we prove that the strong consistency of the EMS option price estimator holds for a wider class of univariate payoffs than those restricted by Lipschitz condition. Numerical experiments demonstrate that EMS can also substantially increase simulation accuracy in the extended setting.

关键词： Monte carlo Black-scholes GARCH

TRANSMISSION DYNAMICS AND OPTIMAL CONTROL OF AN INFLUENZA MODEL WITH QUARANTINE AND TREATMENT

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International Journal of Biomathematics 2012年第3期5卷 177-190页

作者： WEI-WEI SHI yuan-shun TAN Department of Applied Mathematics Xi ' an Jiaotong University Xi'an 710049 P. R. China School of Science Chongqing Jiaotong University Chongqing P. R. China

We develop an influenza pandemic model with quarantine and treatment, and analyze the dynamics of the model. Analytical results of the model show that, if basic repro- duction number R0 〈 1, the disease-free equilibrium （DFE） is globally asymptotically stable, if R0〉 1, the disease is uniformly persistent. The model is then extended to assess the impact of three anti-influenza control measures, precaution, quarantine and treat- ment, by re-formulating the model as an optimal control problem. We focus primarily on controlling disease with a possible minimal the systemic cost. Pontryagin＇s maximum principle is used to characterize the optimal levels of the three controls. Numerical sim- ulations of the optimality system, using a set of reasonable parameter values, indicate that the precaution measure is more effective in reducing disease transmission than the other two control measures. The precaution measure should be emphasized.

关键词： Influenza model equilibrium basic reproduction number stability persistence optimal control quarantine precaution.

Controllable optical multistability in hybrid optomechanical system assisted by parametric interactions

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Science China(Physics,Mechanics & Astronomy) 2017年第1期60卷 17-23页

作者： Cheng Jiang Zhang Yin Zhai yuan shun Cui GuiBin Chen School of Physics and Electronic Electrical Engineering Huaiyin Normal University Huai'an 223300 China Jiangsu Key Laboratory of Modern Measurement Technology and Intelligent Systems Huaiyin Normal University Huai'an 223300 China

We theoretically investigate the multistable behavior of a hybrid optomechanical system, in which a charged mechanical resonator is coupled via Coulomb interaction to an optomechanical cavity containing an optical parametric amplifier （OPA）. It is shown that the multistable behavior of the mean intracavity photon number can be controlled flexibly by adjusting the nonlinear gain parameter of the OPA, the phase of the field pumping the OPA, the power and frequency of the field driving the cavity, and the Coulomb coupling strength between the two charged mechanical resonators. In particular, the increase of the nonlinear gain parameter can result in a transition from bistability to tristability. Moreover, the effect of the Coulomb coupling strength on the bistable behavior of the steady-state positions of the two mechanical resonators is discussed.

关键词： cavity optomechanics optical multistability optical parametric amplifier Coulomb interaction

THE DYNAMICAL BEHAVIOR OF NON-SMOOTH SYSTEM WITH IMPULSIVE CONTROL STRATEGIES

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International Journal of Biomathematics 2012年第3期5卷 297-313页

作者： yuan-shun TAN JU-HUA LIANG SAN-YI TANG Department of Mathematics and Physics Chongqing Jiaotong University Chongqing 400074 P. R. China College of Mathematics and Information Science Shaanxi Normal University Xi'an 710062 P. R. China

Non-smooth system including impulsive strategies at both fixed and unfixed times are analyzed. For the model with fixed impulsive effects, the global stability of pest eradi- cation periodic solution and the dominance of dynamic behavior are investigated. This indicates that the model with fixed moments has the potential to protect the natural enemies from extinction, but under some conditions may also serve to extinction of the pest. The second model is constructed according to the practices of IPM, that is, when the pest population reaches the economic injury level, a combination of biological, cultural, and chemical tactics that reduce pests to tolerable levels is used. Numerical investigations imply that there are several different types of periodic solutions and their maximum amplitudes are always less than the given economic threshold. The results also show that the time series at which the IPM strategies are applied are quite complex, which means that the application and realization of IPM in practice are very difficult.

关键词： Dominance non-smooth system impulsive control strategies integrated pest management global stability.

A Sensor Network Web Platform Based on WoT Technology

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Computer Systems Science & Engineering 2021年第8期38卷 197-214页

作者： shun-yuan Wang Yun-Jung Hsu Sung-Jung Hsiao Wen-Tsai Sung Department of Electrical Engineering National Taipei University of TechnologyTaipei10608TaiwanChina Department of Information Technology Takming University of Science and TechnologyTaipei11451TaiwanChina Department of Electrical Engineering National Chin-Yi University of TechnologyTaichung41170TaiwanChina

This study proposes a Web platform,the Web of Things(WoT),whose Internet of Things(IoT)architecture is used to develop the technology behind a new standard Web *** a remote sensor passes data to a microcontroller for processing,the protocol is often not *** study proposes a WoT platform that enables the use of a browser in a mobile device to control a remote hardware *** optimized code is written using an artificial intelligencebased algorithm in a *** data convergence technology is adopted to process the packets of different protocols and place them on the Web platform for access by other mobile *** platform has high efficiency and cross-platform advantages,with no limitation on the operating *** queueing telemetry transport(MQTT)technology is used to simplify the original HTTP *** that the mobile device is a subscriber,i.e.,the controller,and a microcontroller that connects the sensing device is the *** publishers and subscribers of MQTT need not know each other if they share a message *** intermediate agent role is much like a *** and subscribers do not need to interact,and publishers do not have to wait for subscriber confirmation to cause interactive permission be *** must publishers and subscribers be online at the same time,and they are free to choose when to get *** proposed WoT method is compared with the traditional IoT method regarding data *** results show that the proposed method can save time in processing large amounts of data,as the traditional IoT method wastes time,especially in data format transfer.

关键词： Embedded systems mobile Web servers big data analysis WoT IoT

Effect of H_2O(g)Content in Circulating Flue Gas on Iron Ore Sintering with Flue Gas Recirculation

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Journal of Iron and Steel Research International 2015年第12期22卷 1107-1112页

作者： Xu-ling CHEN Yun-song HUANG Min GAN Xiao-hui FAN Zhi-yuan YU Li-shun yuan School of Minerals Processing and Bioengineering Central South University

The influence of H2O （g） content in circulating flue gas on sintering was studied by simulating the flue gas circulating sintering. The results show that the burning speed of solid fuel and the heat transfer rate during sintering process are improved when the H2O （g） content increases from 0 to 6%, which accelerates the sintering speed. However, when the H2O （g） content exceeds 6 %, the over-wet zone in sinter bed is thickened, which deteriorates the permeability of sintering bed. In addition, the magnetite content in sinter increases, while the acicular calcium ferrite content decreases. Accordingly, the sinter yield and tumble index decrease with excessive H2O （g） content. To guarantee the yield and quality of sinter, the favourable H2O （g） content in circulating flue gas should be controlled to be less than 6%.

关键词： flue gas circulating sintering burning speed heat front flame front sinter

Global stability of an age-structured model of smoking and its treatment

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International Journal of Biomathematics 2023年第1期16卷 53-75页

作者： yuan-shun Tan Xiao-Xue Li Jing Yang R.A.Cheke Department of Mathematics Chongqing Jiaotong University Chongqing 400074P.R.China Natural Resources Institute University of Greenwich at Medway Central AvenueChatham MaritimeChatham KentME44TBUK

Smoking is a serious global public health *** ability to quit smoking is closely related to age;in addition,personal determination and education usually play an important role in quitting *** order to capture such characteristics,we developed a novel age-structured smoking dynamical *** defining the smoking generation number Ro,the local stability,global stability of the boundary equilibrium and endemic equilibrium are obtained using Lyapunov *** uniform persistence and the well-posedness and asymptotic smoothness of the solutions are also *** analyzes show that the lower the age of onset of smoking and the higher the determination to stop,the greater the likelihood of quitting smoking and numerical studies support the theoretical results.

关键词： Smoking age-structured model stability Lyapunov function

Structure Model of Granules for Sintering Mixtures

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Journal of Iron and Steel Research International 2014年第10期21卷 905-909页

作者： Li-shun yuan Xiao-hui FAN Min GAN Gui-ming YANG Yi WANG School of Minerals Processing and Bioengineering Central South University

Structure model of granules, boundary value of nucleus and powder, and the relationship between granula- tion efficiency and boundary value were investigated. Granules of sintering mixtures are composed of adhesive powder and nucleus. In the mixtures, particles larger than 1.00 mm act as nucleus and particles smaller than 0.25 mm act as adhesive powder. Particles with size between 0.25--1.00 mm can be adhesive powder as well as nucleus depending on the granulation conditions. When the boundary value is close to 0.25 mm, the granulation efficiency is lower than 50%. When the boundary value is close to 1.00 mm, the granulation efficiency is above 90%. The boundary value is influenced by the iron ore type, granulation moisture, fineness of raw materials and burnt-lime activity. Good adhe- sive capability, suitable moisture content, appropriate particle size distribution and high burnt-lime activity make the boundary value move towards 1.00 mm and improve the granulation efficiency.

关键词： iron ore sintering structure model granulation