Algorithmic computation of generalized symmetries of nonlinear evolution and lattice equations

A straightforward algorithm for the symbolic computation of generalized (higher‐order) symmetries of nonlinear evolution equations and lattice equations is presented. The scaling properties of the evolution or lattice equations are used to determine the polynomial form of the generalized symmetries. The coefficients of the symmetry can be found by solving a linear system. The method applies to polynomial systems of PDEs of first order in time and arbitrary order in one space variable. Likewise, lattices must be of first order in time but may involve arbitrary shifts in the discretized space variable. The algorithm is implemented in Mathematica and can be used to test the integrability of both nonlinear evolution equations and semi‐discrete lattice equations. With our Integrability Package, generalized symmetries are obtained for several well‐known systems of evolution and lattice equations. For PDEs and lattices with parameters, the code allows one to determine the conditions on these parameters so that a sequence of generalized symmetries exists. The existence of a sequence of such symmetries is a predictor for integrability. This revised version was published online in June 2006 with corrections to the Cover Date.     

IPC技术在VB中的应用

提出了在VB环境下，如何使用IPC技术解决多程序之间的数据传递问题和存储器共用问题的一种方法。     

基于FPGA的红外序列图像动态压缩显示

高位宽红外相机数字视频信号在向8位宽模拟信号线性压缩显示转换时存在细节丢失的现象。针对这一问题,提出了一种新算法,即先利用高斯滤波器对红外数字图像进行低通滤波,然后将低频图像进行线性压缩后再进行直方图均衡运算,之后与滤波产生的高频细节信号进行叠加后送到D/A芯片进行模拟显示。详细讨论了该算法在FPGA嵌入式系统上的具体硬件结构和实现方法,并对12位相机采集的图像进行了实时压缩显示实验。最终实验结果证明,该系统在进行压缩显示时可以很好地显示传统压缩算法无法显示的细节信息,并有效抑制了图像的高频噪声。     

From ODE to DDE

In this paper, by considering ordinary differential equation (ODE) as a special case and a starting point of delay differential equation (DDE), we will show that some typical topological methods such as continuation theorems can be applied to detect some dynamics of DDE like periodic solutions. Several problems will be presented.      

基于PCAuto5.0的温度传感器检测台的设计

阐述了利用力控组态软件PCAuto5.0对汽车发动机冷却水系统温度传感器进行自动化检测的设计与实现.考虑到组态软件对采集时间的限制,利用VB对USB2016采集卡进行控制,通过DDE的方式实现VB与组态软件数据通信.系统利用PCAuto5.0提供的标准控件,实现了动态加载并更新数据库.该系统在现场运行状态良好,可以推广到类似的项目开发中.     

基于DDE与Winsock的WinCC数据通信

根据生产系统的控制要求,设计了一种基于动态数据交换（DDE）和Winsock的并适用于生产运行环境下的实时监控系统。系统采用PLC为核心控制设备,并以交换机为主要通信设备,构建了控制网络。利用WinCC完成上位机HMI程序设计及数据采集功能,利用VB6.0完成数据通信程序设计。该设计应用DDE技术实现对WinCC的数据采集功能,并利用Winsock控件完成了发送数据到生产调度网的功能,从而搭建了工业现场的信息化管理平台。     

Bifurcation analysis of bacteria and bacteriophage coexistence in the presence of bacterial debris

The dynamics of bacteria and bacteriophage coexistence in the presence of bacterial debris, in a marine environment, was studied using a system of delay differential equations (DDE). The system exhibits a rich variety of behavior in terms of two control parameters values: the bacteriophage burst size β, and the lysing time delay τ. Limit cycles of various periodicity, quasiperiodicity, period doubling, chaotic bands and toroidal chaos were identified using basic tools of non-linear dynamics analysis: first return maps, Poincaré sections, Fourier spectrum, and largest Lyapunov exponents.     

基于内存映射文件的数据交换技术及其在测控软件中的应用

系统介绍了在Windows98下，通过使用内存映射方式，实现应用程序间信息实时交互的原理，同时，给出了使用这种方法实现应用程序通信的实例。     

基于DDE和Socket技术的网络控制系统仿真平台

文章从控制系统与实际网络相结合构成网络控制系统出发,应用动态数据交换（DDE,Dynamic Data Exchange）协议和Socket网络通信技术,构建了基于Matlab／Simulink的网络控制系统仿真平台。以起重机为网络远程被控对象,通过仿真平台将实际网络引入起重机控制系统,揭示了网络延迟对该系统的影响。     

电力监控系统多屏显示的设计与实现

文章讨论了监近系统多屏显示的界面特色及实现技术,阐述了Ｗｉｎｄｏｗｓ应用程序间ＤＤＥ动态数据交换的通讯机制及设计技巧,说明了Ｗｉｎｄｏｗｓ环境下运行外部程序的控制策略。