Power Builder6.0／6.5中的分布式计算

概述了Power Builder下进行分布式计算的原理及具体实现过程，并且编写了一个在Internet网上常用的聊天室软件。     

用条纹图形拼接法测量三维大物体面形

三维物体面形的测量在各个领域中有着广泛的应用，用莫尔法、调制光场分析法测量具有非接触性、高精度、快速的特点，但对于大物体的测量却存在着许多困难，诸如阴影噪声难以消除、条纹对比度低。考虑到图形的相关性，本文提出了一种基于多孔径拼接原理的测量三维大物体面形的方法：条纹图形拼接法，给出了数学模型、计算机模拟结果和实验结果。     

焊接扭转变形分析方法研究

大型薄壁梁在焊接拼装过程中常常会出现扭转变形。本文采用二种不同的数值方法对焊接扭转变形的动态过程进行了分析，比较全面系统地论述了研究的方法，阐述了扭转变形的形成机制，它们无论对理论研究还是对工程中的实际应用均有重要意义     

Differential geometrical structures related to forecasting error variance ratios

Differential geometrical structures (Riemannian metrics, pairs of dual affine connections, divergences and yokes) related to multi-step forecasting error variance ratios are introduced to a manifold of stochastic linear systems. They are generalized to nonstationary cases. The problem of approximating a given time series by a specific model is discussed. As examples, we use the established scheme to discuss the AR (1) approximations and the exponential smoothing of ARMA series for multi-step forecasting purpose. In the process, some interesting results about spectral density functions are derived and applied.     

Effective bandwidths at multi-class queues

Consider a queue which serves traffic from a number of distinct sources and which is required to deliver a performance guarantee, expressed in terms of the mean delay or the probability the delay exceeds a threshold. For various simple models we show that an effective bandwidth can be associated with each source, and that the queue can deliver its performance guarantee by limiting the sources served so that their effective bandwidths sum to less than the capacity of the queue.     

Moduli space of potentials in the Aharonov-Bohm effect

We present a simplified derivation of the fact that the set of gauge equivalence classes or moduli space of flat connections (potentials) in the abelian Aharonov-Bohm effect, is isomorphic to the circle. The length of this circle is the absolute value of the electric charge.     

Two-Dimensional Helmholtz Spaces

We study two-dimensional manifolds whose infinitesimally small neighborhoods have the structures of Helmholtz planes. We deal with the main objects related to Helmholtz spaces: in particular, we determine the metric function f and introduce the concept of quasimetric connection and geodesic. For some Helmholtz spaces we prove the existence of isothermal coordinates.     

Space of Hermitian Triples and Ashtekar–Isham Quantization

We generalize the Ashtekar–Isham construction for quantizing gauge fields to the case where the configuration variables belong to the space of Hermitian triples, not Hermitian connections.     

Homoclinic connections and numerical integration

One of the best known mechanisms of onset of chaotic motion is breaking of heteroclinic and homoclinic connections. It is well known that numerical integration on long time intervals very often becomes unstable (numerical instabilities) and gives rise to what is called “numerical chaos”. As one of the initial steps to discuss this phenomenon, we show in this paper that Euler's finite difference scheme does not preserve homoclinic connections. This revised version was published online in June 2006 with corrections to the Cover Date.