GIS中矢量图形的结构分析与VC++中的实现

简要讨论了GIS各类矢量图形元素间的空间拓朴结构及基位置关系 ,并用VC 6 . 0及MFC具体分析了圆弧与多边形区域的相交关系及实现。为利用VC开发专用图形软件提供了有用帮助。     

Boundary knot method for 2D and 3D Helmholtz and convection–diffusion problems under complicated geometry

The boundary knot method (BKM) of very recent origin is an inherently meshless, integration‐free, boundary‐type, radial basis function collocation technique for the numerical discretization of general partial differential equation systems. Unlike the method of fundamental solutions, the use of non‐singular general solution in the BKM avoids the unnecessary requirement of constructing a controversial artificial boundary outside the physical domain. The purpose of this paper is to extend the BKM to solve 2D Helmholtz and convection–diffusion problems under rather complicated irregular geometry. The method is also first applied to 3D problems. Numerical experiments validate that the BKM can produce highly accurate solutions using a relatively small number of knots. For inhomogeneous cases, some inner knots are found necessary to guarantee accuracy and stability. The stability and convergence of the BKM are numerically illustrated and the completeness issue is also discussed. Copyright © 2003 John Wiley & Sons, Ltd.     

Node-pair reliability of network systems with small distances between adjacent nodes

A new method for computing the node-pair reliability of network systems modeled by random graphs with nodes arranged in sequence is presented. It is based on a recursive algorithm using the “sliding window” technique, the window being composed of several consecutive nodes. In a single step, the connectivity probabilities for all nodes included in the window are found. Subsequently, the window is moved one node forward. This process is repeated until, in the last step, the window reaches the terminal node. The connectivity probabilities found at that point are used to compute the node-pair reliability of the network system considered. The algorithm is designed especially for graphs with small distances between adjacent nodes, where the distance between two nodes is defined as the absolute value of the difference between the nodes’ numbers. The maximal distance between any two adjacent nodes is denoted by Γ(G), where G symbolizes a random graph. If Γ(G)=2 then the method can be applied for directed as well as undirected graphs whose nodes and edges are subject to failure. This is important in view of the fact that many algorithms computing network reliability are designed for graphs with failure-prone edges and reliable nodes. If Γ(G)=3 then the method's applicability is limited to undirected graphs with reliable nodes. The main asset of the presented algorithms is their low numerical complexity—O(n), where n denotes the number of nodes.     

一般应力比时焊接结构S－N曲线的预测方法

本文考虑了焊接结构的几何形状、受载形式、应力比、残余应力、尺寸效应以及材料等因素对疲劳寿命的影响，利用Ｐｅｔｅｒｓｏｎ公式和极值疲劳切口系数概念，建立了一般应力比时焊接结构Ｓ－Ｎ曲线的预估模型．文中对几类典型的焊接结构的Ｓ－Ｎ曲线进行了预测，预测值与实验结果符合较好．本文方法可以大量减少疲劳实验，具有一定的工程实用价值．     

不含4圈的最大简单图边数的下界

证明了具有不小于6个顶点的不包含4圈的简单图的最大可能边数的下界是2n-5。     

ELNF演算的解释技术

ＥＬＮＦ演算是我们在ＬＮＦ演算的基础上扩充逻辑程序设计能力而得到的一种函数／逻辑演算系统，它构成了作者设计的函数／逻辑语言ＲＦＵＮＬＯＧ的基础．本文介绍ＥＬＮＦ演算的解释实现技术，包括数据结构、系统结构以及各个模块的设计思想．最后给出了在此解释系统下，几个典型程序的运行时间．     

Automating the identification and analysis of protein {beta}-barrels

ßBarrels are widespread and well-studied featuresof a great many protein structures. In this paper an unsuper-visedmethod for the detection of P-barrels is developed based ontechniques from graph theory. The hydrogen bonded connectivityof ß-sheets is derived using standard pattern recognitiontechniques and expressed as a graph. Barrels correspond to topologicalrings in these connectivity graphs and can thus be identifiedusing ring perception algorithms. Following from this, the characteristictopological structure of a barrel can be expressed using a novelform of reduced nomenclature that counts sequence separationsbetween successive members of the ring set These techniquesare tested by applying them to the detection of barrels in anon-redundant subset of the Brookhaven database. Results indicatethat topological rings do seem to correspond uniquely to ß-barrelsand that the technique, as implemented, finds the majority ofbarrels present in the dataset.     

烧结通用配料计算软件系统的开发

本文介绍了烧结通用配料计算软件系统的总体结构，软件的功能及其设计特点，该软件已在多个烧结经验中得到成功应用。     

基于时频分析的地层吸收系数计算方法

时频分析方法是傅立叶变换及分析的发展,是地震信号处理的重要分析工具,其方法很多、应用广泛。重点介绍基于多种小波基的时频分析方法及S变换与广义S变换方法的时频分析方法,并应用于计算地层吸收系数,其结果优于常规的FFT方法,具有较高的分辨率。