A Method for Obtaining Sequence Transformations

A formulation of a method for obtaining a sequence transformationfrom a certain set of sequences is given. This method, whichis called TSE, was first introduced by Kowalewski. The domainof acceleration and the kernel of a sequence transformationobtained by TSE of a certain type are given. Well-known sequencetransformations such as the Aitken ² process and Lubkin's Wtransformation are obtained by TSE. Applying TSE to a certainset of sequences, the kernel and the domain of accelerationof the W transform are given.     

A Simple Inspection Scheme for Two Types of Defect

The paper examines a problem in quality inspection for two independent defects, A and B. For defect A, process control is at least as important as product screening. Low-cost, rapid sequential inspection takes place for a run of k consecutive type-A defectives. When this occurs, the production process is halted and, if necessary, adjusted, and the run of k defectives is discarded. The entire pre-run sequence is retained, forming the production run. No type-B defectives are permitted; testing for this type of defect is expensive, so detection is by Dorfman screening of the production run. Features of interest are the choice of k in relation to the average length of a production run and the outgoing proportion defective, the average cost per production run of testing for attribute B, and the average number of items finally accepted per production run.     

A Simple Structural Analysis Method for DAEs

We describe a straightforward method for analysing the structure of a differential-algebraic system. It generalizes the method of Pantelides, but is more directly informative and applies to DAEs with derivatives of any order. It naturally leads to a numerical method for the initial value problem that combines projection and index reduction. We illustrate the method by examples, and justify it with proofs. We prove that it succeeds on a fairly wide class of systems encountered in practice, and show its relation to the Pantelides method and to the Campbell-Gear derivative-array equations.This revised version was published online in October 2005 with corrections to the Cover Date.     

Galerkin方法的一种简单后处理过程

基于近似惯性流形思想,以流函数形式定常Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程为例,给出了一种简单的后处理Ｇａｌｅｒｋｉｎ方法。其主要思想是利用近似惯性流形概念和对真解的一种新的分解,构造高低频分量间的近似作用规律。文中证明了这种简单的后处理Ｇａｌｅｒｋｉｎ方法可以较小的代价获得较经典Ｇａｌｅｒｋｉｎ方法高得多的精度。     

一种新的计算Timoshenko梁截面剪切系数的方法

Timoshenko梁理论中考虑了截面剪切变形的影响,推导了一种新的计算剪切系数的方法,首先采用悬臂梁纯弯曲变形条件下截面剪应力分布的精确解,基于能量原理得到了各种梁截面剪切系数新的表达式,然后推导了弯扭耦合变形条件下截面剪应力分布的精确解,进一步获得了该条件下截面的剪切系数.结果表明,悬臂梁端面作用力偏离截面的弯曲中心将使剪切系数变小,通过与Cowper计算结果的对比发现结果偏小,其原因是Cowper没有考虑与外力垂直的剪应力的影响,因此新的计算结果更优越.     

A Heuristic Tree-search Method of Selecting Face Schedules at a Colliery

In the course of work on developing a planning system covering several levels of operations the problem has arisen of selecting the best schedule of coal faces and methods of work on them over an 18-month period at a colliery. A colliery has a number of faces which can come into operation at any time and in any order. The time at which faces are replaced depends on the time taken to work these out which, in turn, depends on the method of work used. A number of methods can be used on each face producing different results, and using different amounts of resources.Since the method would be used as a routine for a large number of collieries, an empirical near-optimum approach has been used which uses a mixture of heuristics, integer programming and search through a decision-tree.A computer program has been used successfully and is now being introduced for routine use.     

求解线性规划的一种单纯形矩阵法

线性规划的单纯形法一直是运筹学教学中的难点,是求解线性规划的一种重要方法.通过实例从代数角度探讨了单纯形法的迭代思想,提出了用单纯形矩阵求解线性规划的方法.同传统的单纯形表计算比较而言,此方法操作简单,不易出错,为线性规划的求解提供了一种行之有效的方法。     

A Simple Finite Element Method for Meteorological Problems

A Galerkin method is applied to simple two dimensional equationsimportant in meteorological problems. The construction of thespace of trial functions for the Galerkin method is done usingthe "finite element" method, where the functions are definedas polynomials on individual elements and values are matchedon element boundaries. This method is applied to passive advectionproblems and to a non-linear gravity wave problem. The resultsare compared with those obtained by finite difference methodsand the computation time for given accuracy is shown to be atleast as short using the finite element method as with finitedifferences. Sharp local gradients are especially well handled.Extension of this approach to irregular grids and the possibleuse of higher order polynomials are proposed.     

有界变量线性规划的一种简易解法

本文在[1]的基础上，较系统地叙述了有界变量线性规划一种简易解法的基本思路、方法步骤、理论分析和应用举例。指出，因变量有界所引起的种种麻烦在这里通过单纯形表的小小变动便加以解决了。     

A Simple Finite Element Method for the Reissner-Mindlin Plate

1.IntroductionTheReissner-MindlinmodeldescribesthedefOrmationofaplatesubjecttoatrans-verseload.Thismodel,aswellasitsgeneralizationtoshells,isfrequentlyusedforp1atesandshellsofsmalltomoderatethickness.Itiswellknownthatmanynumeri-calschemesforthismodelaresatisfactoryonlywhenthethicknessparametertisnottoosmal1.Foraverysmallt,somebadbehaviors(suchaJsthelockingphenomenon)mightoccur.Inl986,F.BrezziandM.Fo.ti.l2]derivedanequivalentformulationoftheReissner-MindlinplateequationsbyusingtheHelmholtz…     

矩阵moore—penrose逆的一种简捷求法

本文结出了利用AA~H或A~HA的特征多项式求矩阵A的moore-peuroxe逆的方法。     

A Method for Obtaining Exact Solutions to Partial Differential Equations with Variable Coefficients

This paper describes techniques that can be used to transform PDEs with variable coefficients into equations with constant coefficients. The techniques are illustrated by calculating shear flows over quite general surfaces, by solving the signaling problem for diffusive processes in inhomogeneous materials, and by solving the signaling problem for acoustical waves when the sound speed varies with distance. The techniques may also be used to solve equations governing processes in inhomogeneous, anisotropic materials.     

动载荷识别的非迭代法研究

为了快速准确地识别结构在复杂环境下的承载状态，基于有限元法和Newmark-β法提出了一种非迭代反演方法，并用于识别结构上施加的动载荷.通过探寻测量信息与待演参量之间的关系，建立误差函数，根据最小二乘法实现动载荷的直接识别无需迭代，其中对待反演的分布载荷实施基函数展开，以提高算法的抗不适定性.同时奇异值分解法被用来求解病态方程组.数值算例分别讨论了测量噪声、测点数量、基函数展开、测点位置和不同时间步长对反演结果的影响，结果显示该方法在识别动载荷时具有较高的精度和效率.     

投资组合问题的动态规划方法

关于投资组合问题,Markowitz的均值-方差模型奠定了理论基础。近年来出现了许多简化模型,多目标线性规划模型是其中之一,但是这种线性化方法不便于处理非线性的交易费,本文建立一种动态规划模型和递推算法。     

简单图的一种计数方法

对某一类图的邻接矩阵进行分类 ,从而给出这类图的一种计数方法 ,并且这种方法比较原来的Polya方法更为可行 .     

轨道运动方程数值解的一种加速算法

针对卫星轨道受大气阻力摄动的运动方程,提出了一种数值加速算法,该算法实现简单、计算量小、精度高,适合于各类卫星轨道的方程的求解.     

A Computer Assessment of Media Schedules

This paper outlines the approach made by The London Press Exchange to the media scheduling problem. A rather detailed simulation model of the way television and press schedules reach a target population has been set up. This is used to assess various alternative schedules, i.e. to give an effectiveness rating for each schedule. The marginal rate of return for various alterations to these schedules is also produced. Details of the mathematics in the model and of parts of the computer programs are given. Examples illustrate particular points and the general application.     

求参数置信限的一种方法

本文介绍一种找参数精确置信限和置信区间的一般方法,关键想法是在样本空间中定义一个序。本文主要考虑单参数统计模型,对序的优良性（即相应的置信限的优良性）作了讨论,指出应以得分函数的大小为依据在样本空间中定义序。还证明了用最大似然估计定义序得到的置信限是一个单调函数的唯一零点,从而通过解方程算出置信限。