飞向Halo轨道的太阳帆航天器轨迹优化设计

研究了太阳帆航天器从地球同步轨道飞向日-地第2Lagrange(L2)点Halo轨道时其转移并入轨的轨迹优化设计问题。提出了分3阶段优化设计的方法:首先调整航天器逃离地球的飞行轨迹,使其比较接近目标Halo轨道的不变流形;再借助不变流形,用遗传算法求解相应的最优控制,使其转移到目标Halo轨道的不变流形上;最后航天器将沿流形飞行完成入轨。数值仿真结果表明,提出的方法可以得到相当好的转移轨道。由此显示:将转移轨道分为若干阶段,借助不变流形,用遗传算法求解最优控制问题的轨道优化设计方法对于此类小推力变轨问题是切实可行的。     

钻井布局方案最优化方法

本文研究钻井布局最优方案,提高已有井的使用率。通过建立非线性规划模型分别在欧式距离(l∞模距离)和纵横距离(l2模距离)下求解具体布局方案。     

A Genetic Algorithm for Delay-constrained Least-cost Multicast Routing

The delay-constrained least-cost multicast routing problem is introduced and then a related genetic algorithm is proposed. Finally, simulation results are shown to prove that the genetic algorithm is fast and effective.     

Optimal Polygonal Approximation of Digital Planar Curves Using Genetic Algorithm and Tabu Search

Three heuristic algorithms for optimal polygonal approximation of digital planar curves is presented.With Genetic Algorithm (GA), improved Genetic Algorithm (IGA) based on Pareto optimal solution and Tabu Search (TS), a near optimal polygonal approximation was obtained.Compared to the famous Teh-chin algorithm, our algorithms have obtained the approximated polygons with less number of vertices and less approximation error.Compared to the dynamic programming algorithm, the processing time of our algorithms are much less expensive.     

从ACM竞赛谈计算机实验教学改革

在计算机实验教学中改革教学模式,提高学生的积极性,加强对学生创新能力的培养,是高校实验教学改革的重要课题。文中探讨了ACM国际大学生程序设计竞赛对计算机实验教学改革和课程建设的促进作用,以及关于通过组织学生参加ACM竞赛,激发学生的自主创新意识的思路与体会。     

浅论逻辑在第五代计算机中的作用

本文主要通过第五代计算机过渡性的核心语言PROIOG—逻辑程序设计语言,讨论(一阶谓词)逻辑在第五代计算机中的作用。     

Improving the Estimations of VaR-GARCH Using Genetic Algorithm

1　 IntroductionIn recent years,well-publicized losses suffered by some institutions such as Natwest,Baring Bank,Metallgesellschaft,and Orange County have brought risk management tothe core of policy making and public discussion,and there has a widespread call for betterquantification of financial market risk facing regulations and financial society.At theforefront of this clamor for a standardizaed risk measure has been Value at Risk( Va R) [1～ 5] .Va R is defined as the expected loss on…     

国外鲟鱼类渔业生物学研究现状

概述了国外鲟类生理学、遗传学及生态学领域的研究现状。从微观和宏观两方面描述了国外鲟类成熟性腺、受精卵、胚胎发育、营养生理、遗传分析及生态等内容的研究结果。     

关于推广Polak算法模型收敛性定理的改进

本文改进了 Polak 定理[1]的收敛性条件。