A new three-dimensional chaotic system and its modified generalized projective synchronization

Based on the Chen chaotic system,this paper constructs a new three-dimensional chaotic system with higher order nonlinear term and studies the basic dynamic behaviours of the system. The modified generalized projective synchronization has been observed in the coupled new three-dimensional chaotic system with unknown parameters. Furthermore,based on Lyapunov stability theory,it obtains the control laws and adaptive laws of parameters to make modified generalized projective synchronization of the coupled new three-dimensional chaotic systems. Numerical simulation results are presented to illustrate the effectiveness of this method.     

Adaptive generalized matrix projective lag synchronization between two different complex networks with non-identical nodes and different dimensions

<正>The adaptive generalized matrix projective lag synchronization between two different complex networks with non-identical nodes and different dimensions is investigated in this paper.Based on Lyapunov stability theory and Barbalat’s lemma,generalized matrix projective lag synchronization criteria are derived by using the adaptive control method.Furthermore,each network can be undirected or directed,connected or disconnected,and nodes in either network may have identical or different dynamics.The proposed strategy is applicable to almost all kinds of complex networks.In addition,numerical simulation results are presented to illustrate the effectiveness of this method,showing that the synchronization speed is sensitively influenced by the adaptive law strength,the network size,and the network topological structure.     

CDMA——新世纪的移动通信技术

 CDMA自20世纪90年代中期投入商用以来,以其独特的魅力在全球得到了快速发展。特别是近两年在通信走向个人化的时代背景下,CDMA更是呈现出高速稳步发展的态势。一、CDMA的形成与发展CDMA是码分多址(CodeDivisionMultipleAccess)的英文缩写,它是在数字技术的分支---扩频通信技术上发展起来的一种崭新而成熟的无线通信技术。CDMA技术的原理是基于扩频技术,即将需传送的具有一定信号带宽信息数据,用一个带宽远大于信号带宽的高速伪随机码进行调制,使原数据信号的带宽被扩展,再经载波调制并发送出去。     

Nonlinear feedback synchronisation control between fractional-order and integer-order chaotic systems

This paper focuses on the synchronisation between fractional-order and integer-order chaotic systems.Based on Lyapunov stability theory and numerical differentiation,a nonlinear feedback controller is obtained to achieve the synchronisation between fractional-order and integer-order chaotic systems.Numerical simulation results are presented to illustrate the effectiveness of this method.     

A new four-dimensional hyperchaotic Chen system and its generalized synchronization

Based on the Chen chaotic system, a new four-dimensional hyperchaotic Chen system is constructed, and the basic dynamic behaviours of the system were studied, and the generalized synchronization has been observed in the coupled four-dimensional hyperchaotic Chen system with unknown parameters. The Routh--Hurwitz theorem is used to derive the conditions of stability of this system. Furthermore based on Lyapunov stability theory, the control laws and adaptive laws of parameters are obtained to make generalized synchronization of the coupled new four-dimensional hyperchaotic Chen systems. Numerical simulation results are presented to illustrate the effectiveness of this method.     

数字电视技术

 当前,世界科技迅猛发展,由于微电子技术、超大规模集成电路技术、数字信号处理技术、计算机技术的突飞猛进,使数字电视的发展已取得了令人鼓舞的成果。技术先进国家的电视演播室设备数字化已完成,世界广播电视已经进入数字化时代。美国计划在2006年关闭模拟电视;英国计划在2010年关闭模拟电视;日本计划在2011年关闭模拟电视。我国广播影视“十五”计划也明确提出2003年全面开展有线数字电视,2005年有线数字电视用户达3000万,到2015年,我国将关闭模拟电视,并承诺2008年奥运会将使用数字电视技术向全球传送比赛信息。