A new theory on the construction of optimal truncated Low-Dimensional Dynamical Systems (LDDSs) with different physical meanings has been developed, The physical properties of the optimal bases are reflected in the us...A new theory on the construction of optimal truncated Low-Dimensional Dynamical Systems (LDDSs) with different physical meanings has been developed, The physical properties of the optimal bases are reflected in the user-defined optimal conditions, Through the analysis of linear and nonlinear examples, it is shown that the LDDSs constructed by using the Proper Orthogonal Decomposition (POD) method are not the optimum. After comparing the errors of LDDSs based on the new theory POD and Fourier methods, it is concluded that the LDDSs based on the new theory are optimally truncated and catch the desired physical properties of the systems.展开更多
The video game presented in this paper is a prey-predator game where two preys (human players) must avoid three predators (automated players) and must reach a location in the game field (the computer screen) called pr...The video game presented in this paper is a prey-predator game where two preys (human players) must avoid three predators (automated players) and must reach a location in the game field (the computer screen) called preys’ home. The game is a sequence of matches and the human players (preys) must cooperate in order to achieve the best perform- ance against their opponents (predators). The goal of the predators is to capture the preys, which are the predators try to have a “rendez vous” with the preys, using a small amount of the “resources” available to them. The score of the game is assigned following a set of rules to the prey team, not to the individual prey. In some situations the rules imply that to achieve the best score it is convenient for the prey team to sacrifice one of his components. The video game pursues two main purposes. The first one is to show how the closed loop solution of an optimal control problem and elementary sta- tistics can be used to generate (game) actors whose movements satisfy the laws of classical mechanics and whose be- haviour simulates a simple form of intelligence. The second one is “educational”, in fact the human players in order to be successful in the game must understand the restrictions to their movements posed by the laws of classical mechanics and must cooperate between themselves. The video game has been developed having in mind as players for children aged between five and thirteen years. These children playing the video game acquire an intuitive understanding of the basic laws of classical mechanics (Newton’s dynamical principle) and enjoy cooperating with their teammate. The video game has been experimented on a sample of a few dozen children. The children aged between five and eight years find the game amusing and after playing a few matches develop an intuitive understanding of the laws of classical me- chanics. They are able to cooperate in making fruitful decisions based on the positions of the preys (themselves), of the predators (their opponent展开更多
Ⅰ. INTRODUCTIONIt has been known that the theory of topological dynamics has very powerful applications to autonomous as well as to nonautonomous ordinary differential equations. However,so far we have not known any ...Ⅰ. INTRODUCTIONIt has been known that the theory of topological dynamics has very powerful applications to autonomous as well as to nonautonomous ordinary differential equations. However,so far we have not known any similar works for functional differential equations, essentially in that the state space C([-r, 0], R^n) is not compact.展开更多
In this paper a prey-predator video game is presented. In the video game two predators chase a prey that tries to avoid the capture by the predators and to reach a location in space (i.e. its “home”). The prey is an...In this paper a prey-predator video game is presented. In the video game two predators chase a prey that tries to avoid the capture by the predators and to reach a location in space (i.e. its “home”). The prey is animated by a human player (using a joypad), the predators are automated players whose behaviour is decided by the video game engine. The purpose of the video game is to show how to use mathematical models to build a simple prey-predator dynamics representing a physical system where the movements of the game actors satisfy Newton’s dynamical principle and the behaviour of the automated players simulates a simple form of intelligence. The game is based on a simple set of ordinary differential equations. These differential equations are used in classical mechanics to describe the dynamics of a set of point masses subject to a force chosen by the human player, elastic forces and friction forces (i.e. viscous damping). The software that implements the video game is written in C++ and Delphi. The video game can be downloaded from: http://www.ceri.uniroma1.展开更多
研究时滞周期模型()()()(())()(())nn nx t v t x t x t ttx t t′+α?θ+?τ?τ=λ其中m、n是正整数,v(t),λ(t)是正周期函数,周期为ω,τ(t)为非负ω周期函数,获得方程存在一个正周期解的充分条件,推广改进了已有结果[Saker,Comput.Ma...研究时滞周期模型()()()(())()(())nn nx t v t x t x t ttx t t′+α?θ+?τ?τ=λ其中m、n是正整数,v(t),λ(t)是正周期函数,周期为ω,τ(t)为非负ω周期函数,获得方程存在一个正周期解的充分条件,推广改进了已有结果[Saker,Comput.Math.Appl.2002(44)623-632]。并举例说明了定理的应用。展开更多
基金The project supported by the National Natural Science Foundation of ChinaLNM,Institute of Mechanics,CAS
文摘A new theory on the construction of optimal truncated Low-Dimensional Dynamical Systems (LDDSs) with different physical meanings has been developed, The physical properties of the optimal bases are reflected in the user-defined optimal conditions, Through the analysis of linear and nonlinear examples, it is shown that the LDDSs constructed by using the Proper Orthogonal Decomposition (POD) method are not the optimum. After comparing the errors of LDDSs based on the new theory POD and Fourier methods, it is concluded that the LDDSs based on the new theory are optimally truncated and catch the desired physical properties of the systems.
文摘本文综述随机动力系统的基本概念、理论、方法与应用,内容包括Brownian运动、Lévy运动和随机微分方程及其解的刻画。重点讨论通过量化指标、不变结构、几何方法和非高斯性态来理解随机动力学现象。本文还介绍了段金桥的著作《An Introduction to Stochastic Dynamics(随机动力系统导论)》的基本内容。
文摘The video game presented in this paper is a prey-predator game where two preys (human players) must avoid three predators (automated players) and must reach a location in the game field (the computer screen) called preys’ home. The game is a sequence of matches and the human players (preys) must cooperate in order to achieve the best perform- ance against their opponents (predators). The goal of the predators is to capture the preys, which are the predators try to have a “rendez vous” with the preys, using a small amount of the “resources” available to them. The score of the game is assigned following a set of rules to the prey team, not to the individual prey. In some situations the rules imply that to achieve the best score it is convenient for the prey team to sacrifice one of his components. The video game pursues two main purposes. The first one is to show how the closed loop solution of an optimal control problem and elementary sta- tistics can be used to generate (game) actors whose movements satisfy the laws of classical mechanics and whose be- haviour simulates a simple form of intelligence. The second one is “educational”, in fact the human players in order to be successful in the game must understand the restrictions to their movements posed by the laws of classical mechanics and must cooperate between themselves. The video game has been developed having in mind as players for children aged between five and thirteen years. These children playing the video game acquire an intuitive understanding of the basic laws of classical mechanics (Newton’s dynamical principle) and enjoy cooperating with their teammate. The video game has been experimented on a sample of a few dozen children. The children aged between five and eight years find the game amusing and after playing a few matches develop an intuitive understanding of the laws of classical me- chanics. They are able to cooperate in making fruitful decisions based on the positions of the preys (themselves), of the predators (their opponent
基金Project supported by the National Natural Science Foundation of China and Science Foundation of Anhu University.
文摘Ⅰ. INTRODUCTIONIt has been known that the theory of topological dynamics has very powerful applications to autonomous as well as to nonautonomous ordinary differential equations. However,so far we have not known any similar works for functional differential equations, essentially in that the state space C([-r, 0], R^n) is not compact.
文摘In this paper a prey-predator video game is presented. In the video game two predators chase a prey that tries to avoid the capture by the predators and to reach a location in space (i.e. its “home”). The prey is animated by a human player (using a joypad), the predators are automated players whose behaviour is decided by the video game engine. The purpose of the video game is to show how to use mathematical models to build a simple prey-predator dynamics representing a physical system where the movements of the game actors satisfy Newton’s dynamical principle and the behaviour of the automated players simulates a simple form of intelligence. The game is based on a simple set of ordinary differential equations. These differential equations are used in classical mechanics to describe the dynamics of a set of point masses subject to a force chosen by the human player, elastic forces and friction forces (i.e. viscous damping). The software that implements the video game is written in C++ and Delphi. The video game can be downloaded from: http://www.ceri.uniroma1.
文摘研究时滞周期模型()()()(())()(())nn nx t v t x t x t ttx t t′+α?θ+?τ?τ=λ其中m、n是正整数,v(t),λ(t)是正周期函数,周期为ω,τ(t)为非负ω周期函数,获得方程存在一个正周期解的充分条件,推广改进了已有结果[Saker,Comput.Math.Appl.2002(44)623-632]。并举例说明了定理的应用。
