关键词： Structural analysis  

摘要： An implicit numerical integration algorithm based on generalized coordinate partitioning is presented for the numerical solution of differential-algebraic equations of motion arising in multibody dynamics. The algorithm employs implicit numerical integration formulas to express independent generalized coordinates and their first time derivative as functions of independent accelerations at discrete integration times. The latter are determined as the solution of discretized equations obtained from state-space, second-order ordinary differential equations in the independent coordinates. All dependent variables in the formulation, including Lagrange multipliers, are determined by satisfying the full system of kinematic and kinetic equations of motion. The algorithm is illustrated using the implicit trapezoidal rule to integrate the constrained equations of motion for three stiff mechanical systems with different generalized coordinate dimensions. Results show that the algorithm is robust and has the capability to integrate differential-algebraic equations of motion for stiff multibody dynamic systems.

关键词： 中学数学   求根公式   一元二次方程  

摘要： 由二次方程的求根公式谈中学数学中算法的稳定性□李玉钊（河南信阳地区教育学院４６４０００）众所周知，对于一个数字系数的一元二次方程ａｘ２＋ｂｘ＋ｃ＝０（ａ≠０），欲求其解，可通过著名的求根公式ｘ１＝－ｂ＋ｂ２－４ａｃ２ｎ，ｘ２＝－ｂ－ｂ２－４ａｃ２ａ（...

关键词： 遗传算法   模糊推理   突变算子  

摘要： 本文在简要介绍遗传算法的基础上,通过引入i位改进子空间的概念,对不同情形下突变概率的最优选取进行了分析,然后采用模糊推理技术来确定选取突变概率的一般性原则。良好的仿真结果显示了本文所提改进策略的有效性。

关键词： 灵活交流   输电系统   移相控制   综合潮流控制器   电力电子  

关键词： Computational physics Gravitation and cosmology  

摘要： We examine the relative performance of algorithms for the calculation of curvature in spacetime. The classical coordinate component method is compared to two distinct versions of the Newman-Penrose tetrad approach for a variety of spacetimes, and distinct coordinates and tetrads for a given spacetime. Within the system GRTensorII, we find that there is no single preferred approach on the basis of speed. Rather, we find that the fastest algorithm is the one that minimizes the amount of time spent on simplification. This means that arguments concerning the theoretical superiority of an algorithm need not translate into superior performance when applied to a specific spacetime calculation. In all cases it is the simplification strategy which is of paramount importance. An appropriate simplification strategy can change an intractable problem into one which can be solved essentially instantaneously.

关键词： 数学模型   算法   生产计划   排序   批量问题  

摘要： 古典库存问题和能力无限的单层批量问题的研究已经有几十年的历史了,但由于实际生产中产品结构往往比较复杂、生产能力总是有限的,因此能力受限的批量问题(尤其是多层批量问题)成为了近年来运筹学、管理科学和工业工程等领域的研究热点之一.本文在综合大量国内外有关文献的基础上,对一般批量问题的数学模型作了比较系统、全面的介绍,重点讨论能力受限的单层批量问题和多层批量问题的一些新算法,并指出一些值得深入研究和努力实践的新方向.

关键词： 软件测试   优化   F-P方程   马尔柯夫链  

摘要： 从数学优化角度对软件测试问题进行探索性研究，将软件测试中的结构测试问题转化为一个组合最优化问题，然后利用Ｆｏｋｋｅｒ－Ｐｌａｎｃｋ方程的离散形式而得到的Ｍａｒｋｏｖ链为基础的一个算法求解．最后给出了几个测试实例的部分数值结果。

ISBN: (纸本)7563209565

关键词： 中国邮员问题   旅行商问题   最坏情形分析   对偶系统   计算智能  

关键词： computational geometry   lines in space   Plucker coordinates   epsilon-nets  

摘要： Questions about lines in space arise frequently as subproblems in three-dimensional computational geometry. In this paper we study a number of fundamental combinatorial and algorithmic problems involving arrangements of n lines in three-dimensional space. Our main results include: 1. A tight Theta(n(2)) bound on the maximum combinatorial description complexity of the set of all oriented lines that have specified orientations relative to the n given lines. 2. A similar bound of Theta(n(3)) for the complexity of the set of all lines passing above the n given lines. 3. A preprocessing procedure using O(n(2+epsilon)) time and storage, for any epsilon > 0, that builds a structure supporting O(log n)-time queries for testing if a line lies above all the given lines. 4. An algorithm that tests the ''towering property'' in O(n(4/3+epsilon)) time, for any epsilon > 0: do n given red lines lie all above n given blue lines? The tools used to obtain these and other results include Plucker coordinates for lines in space and epsilon-nets for various geometric range spaces.