各向异性材料导热系数在非主方向上的转换

在研究热弹性问题时，一般对于各向异性材料，总可以找到三个主方向，并获得关于这三个主方向上的材料常数。一般在建立模型时通常将坐标系选择与主方向一致，从而使问题简化。但若坐标系选择与主方向不一致时，则主方向的数据必须经过转换才能适用于这类坐标系。本文给出了导热系数由主方向向非主方向转换的一般表达式。     

差分 GPS 基准站坐标系统转换误差分析

讨论了差分ＧＰＳ基准站设计中的坐标变换，推导了坐标变换误差的计算式，分析了它们对ＤＧＰＳ精度的影响。计算结果表明坐标变换对ＤＧＰＳ的影响主要来自参考椭球中心平移量误差，提高参考椭球中心平移量的精度是消除坐标变换误差对ＤＧＰＳ精度影响的关键。     

一类非线性时滞系统的稳定化控制器设计研究

针对一类单控制滞后的非线性时滞系统,利用非线性状态变换的方法进行非线性变 换,得到一线性时滞系统模型;然后利用一带控制记忆的积分变换进行精确无滞后化变换,得 到一无滞后的线性能控标准型系统,从而利用分步设计的思想.实现非线性时滞系统的稳定 化控制.一数值例子的仿真研究说明了该方法的有效性.     

生成圆弧的等距线约束方法及其应用

栅格圆弧的生成算法在计算机图形学和图像处理中有着大量的应用．一条曲线一定位于该线两侧的两条到该线距离足够小的等距线之间，或认为该曲线受其两侧的两条等距线的约束．本文从真实圆弧曲线受其两侧的等距圆的约束出发，提出一种生成栅格圆弧的等距线约束算法，并分析了该算法的精度．其优点是可单方向连续生成圆弧，且生成的两个相邻栅格圆之间不会有空隙或重叠，因此可直接用于圆域有关的图形生成和栅格点扩散搜索．本文最后研究了该方法在栅格圆环、圆盘及球面、球等生成及Euclid距离变换中的应用．     

光束变换光学和光束质量研究的某些新进展

本对光束变换光学和光束质量研究的某些新进展，包括二维和三维非高斯光束通过一阶光束系统的传输，一般光束的分类及其光束质量的描述作了评述和分析，并对这一领域中需要解决的困难和问题作了讨论。     

Uniform Distribution, Distance and Expectation Problems for Geometric Features Processing

Complex geometric features such as oriented points, lines or 3D frames are increasingly used in image processing and computer vision. However, processing these geometric features is far more difficult than processing points, and a number of paradoxes can arise. We establish in this article the basic mathematical framework required to avoid them and analyze more specifically three basic problems: (1) what is a random distribution of features, (2) how to define a distance between features, (3) and what is the “mean feature” of a number of feature measurements? We insist on the importance of an invariance hypothesis for these definitions relative to a group of transformations that models the different possible data acquisitions. We develop general methods to solve these three problems and illustrate them with 3D frame features under rigid transformations. The first problem has a direct application in the computation of the prior probability of a false match in classical model-based object recognition algorithms. We also present experimental results of the two other problems for the statistical analysis of anatomical features automatically extracted from 24 three-dimensional images of a single patient's head. These experiments successfully confirm the importance of the rigorous requirements presented in this article.     

Chain Vibration and Dynamic Stress in Three-Dimensional Multibody Tracked Vehicles

A three-dimensional computational finite element procedure for the vibration and dynamic stress analysis of the track link chains of off-road vehicles is presented in this paper. The numerical procedure developed in this investigation integrates classical constrained multibody dynamics methods with finite element capabilities. The nonlinear equations of motion of the three-dimensional tracked vehicle model in which the track link s are considered flexible bodies, are obtained using the floating frame of reference formulation. Three-dimensional contact force models are used to describe the interaction of the track chain links with the vehicle components and the ground. The dynamic equations of motion are first presented in terms of a coupled set of reference and elastic coordinates of the track links. Assuming that the structural flexibility of the track links does not have a significant effect on their overall rigid body motion as well as the vehicle dynamics, a partially linearized set of differential equations of motion of the track links is obtained. The equations associated with the rigid body motion are used to predict the generalized contact, inertia, and constraint forces associated with the deformation degrees of freedom of the track links. These forces are introduced to the track link flexibility equations which are used to calculate the deformations of the links resulting from the vehicle motion. A detailed three-dimensional finite element model of the track link is developed and utilized to predict the natural frequencies and mode shapes. The terms that represent the rigid body inertia, centrifugal and Coriolis forces in the equations of motion associated with the elastic coordinates of the track link are described in detail. A computational procedure for determining the generalized constraint forces associated with the elastic coordinates of the deformable chain links is presented. The finite element model is then used to determine the deformations of the track links resulting from the contact, inertia, and constraint forces. The results of the dynamic stress analysis of the track links are presented and the differences between these results and the results obtained by using the static stress analysis are demonstrated.     

试论面向对象软件的维护

随着面向对象技术的广泛使用,面向对象软件不易维护(原因是维护者不易分析、理解这类软件)的问题已越来越突出。本文在讨论面向对象技术对软件维护影响的基础上,探讨了面向对象软件的维护问题,并提出了解决的对策。     

基于规则学习的空间变换方法及其应用

人工智能领域中的许多问题经常涉及到空间变换。本文提出了一种基于规则学习的空间变换方法，该方法可以应用到智能控制、模式识别、知识获取等方面。本文中给出的智能机器人控制方面的数字实验结果表明，基于规则学习的空间变换方法不仅具有重要的理论意义，而且具有广阔的应用前景。     

基于OPC及DTS接口控制方案的设计与应用

结合OPC规范及数据转换服务(DTS)的主要技术特点,提出了一种基于OPC及DTS技术的接口控制方案。通过这种方案,可以简便有效地实现企业管理层与现场设备层之间的交互。