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Gao J.,Shanghai JiaoTong University | Chen Z.,Shanghai JiaoTong University | Cai Y.,Shanghai JiaoTong University | Xu X.,Shanghai JiaoTong University | And 2 more authors.
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010

We investigate a weighted self-propelled agent system, wherein each agent's direction is determined by its spatial neighbors' directions with exponential weights according to the neighbor numbers. In order to describe the fact that some agents with more neighbors might have larger influence on its neighbors, we introduce a scaling exponent of the neighbor number between 0 and ∞. When the exponent is equal to 1, the convergence efficiency is enhanced in our simulation. Furthermore, as the exponent increases, i.e., the effect of weight becomes stronger, the network of agents becomes easier to achieve direction consensus. © 2010 The American Physical Society. Source


Chen Z.,Shanghai JiaoTong University | Gao J.,Shanghai JiaoTong University | Cai Y.,Shanghai JiaoTong University | Xu X.,University of Shanghai for Science and Technology | Xu X.,Shanghai Academy of Systems Science
Physica A: Statistical Mechanics and its Applications | Year: 2011

We investigate an evolutionary prisoner's dilemma game among self-driven agents, where collective motion of biological flocks is imitated through averaging directions of neighbors. Depending on the temptation to defect and the velocity at which agents move, we find that cooperation can not only be maintained in such a system but there exists an optimal size of interaction neighborhood, which can induce the maximum cooperation level. When compared with the case that all agents do not move, cooperation can even be enhanced by the mobility of individuals, provided that the velocity and the size of neighborhood are not too large. Besides, we find that the system exhibits aggregation behavior, and cooperators may coexist with defectors at equilibrium. © 2010 Elsevier B.V. All rights reserved. Source


Chen Z.,Shanghai JiaoTong University | Gao J.,Shanghai JiaoTong University | Cai Y.,Shanghai JiaoTong University | Xu X.,University of Shanghai for Science and Technology | Xu X.,Shanghai Academy of Systems Science
Physica A: Statistical Mechanics and its Applications | Year: 2011

We study the effects of mobility on the evolution of cooperation among mobile players, which imitate collective motion of biological flocks and interact with neighbors within a prescribed radius R. Adopting the the prisoner's dilemma game and the snowdrift game as metaphors, we find that cooperation can be maintained and even enhanced for low velocities and small payoff parameters, when compared with the case that all agents do not move. But such enhancement of cooperation is largely determined by the value of R, and for modest values of R, there is an optimal value of velocity to induce the maximum cooperation level. Besides, we find that intermediate values of R or initial population densities are most favorable for cooperation, when the velocity is fixed. Depending on the payoff parameters, the system can reach an absorbing state of cooperation when the snowdrift game is played. Our findings may help understanding the relations between individual mobility and cooperative behavior in social systems. © 2011 Elsevier B.V. All rights reserved. Source


Cai Y.-Z.,Shanghai JiaoTong University | Pan N.,Shanghai JiaoTong University | Xu X.-M.,Shanghai JiaoTong University | Xu X.-M.,Shanghai Academy of Systems Science | Xu X.-M.,University of Shanghai for Science and Technology
Kongzhi yu Juece/Control and Decision | Year: 2010

The H∞ filtering for networked control systems with stochastic transmission delay longer than a sampling period and data packet dropout is studied. For the given packet dropout, the filtering error system is modeled as an asynchronous dynamical system with rate constraints on two events. The sufficient condition for guaranteeing the exponential stability and the H∞ constraint of the filtering error system is given by using the theory of asynchronous dynamical systems. The corresponding filter is designed by solving a set of matrix inequalities. The simulation result shows the validity and effectiveness of this method. Source


Liu G.,University of Shanghai for Science and Technology | Liu G.,Shanghai Academy of Systems Science
Advanced Materials Research | Year: 2010

An improved Freeman-Newell functional reasoning model is proposed for the conceptual design of manufacturing process control strategies. The structure in Freeman-Newell model is partitioned into determined subset and undetermined subset. Main framework of the structure is expressed by determined subset. Undetermined subset is presented to express the functions required from next design level. In this way variant design and multi level design reasoning can be supported. Based on the improved Freeman-Newell model, multi level conceptual design methodology for control strategies of manufacturing process is presented. Tracking control algorithm design for a nonlinear manufacturing process plant is provided as the example to verify the design reasoning ability of the improved model. © (2010) Trans Tech Publications. Source

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