Two‐stage component test plans for testing the reliability of a series system

A system reliability is often evaluated by individual tests of components that constitute the system. These component test plans have advantages over complete system based tests in terms of time and cost. In this paper, we consider the series system with n components, where the lifetime of the i‐th component follows exponential distribution with parameter λ_i. Assuming test costs for the components are different, we develop an efficient algorithm to design a two‐stage component test plan that satisfies the usual probability requirements on the system reliability and in addition minimizes the maximum expected cost. For the case of prior information in the form of upper bounds on λ_i's, we use the genetic algorithm to solve the associated optimization problems which are otherwise difficult to solve using mathematical programming techniques. The two‐stage component test plans are cost effective compared to single‐stage plans developed by Rajgopal and Mazumdar. We demonstrate through several numerical examples that our approach has the potential to reduce the overall testing costs significantly. © 2002 John Wiley & Sons, Inc. Naval Research Logistics, 49: 95–116, 2002; DOI 10.1002/nav.1051     

iSIGHT在多目标优化问题中的应用研究

在工程实际中,随着设计要求的日益提高,单一的设计目标已经不能满足设计者的要求。于是多目标设计优化问题在设计领域越来越占据主导地位。目前多目标优化设计方法种类繁多,各有优劣,重点介绍优化设计框架iSIGHT,并就iSIGHT在解决鱼雷壳体结构设计中的多目标优化设计问题中的应用情况进行研究,讨论iSIGHT在解决多目标优化问题中的可行性。     

新时期高校师德建设面临的问题与对策

高等教育发展对师德建设提出的新要求，应采取适当措施探讨高校师德建设的新路径和方法。     

考虑扰动引力影响的弹道助推段误差传播解析计算方法

针对地球扰动引力对弹道导弹惯性导航精度影响日益突出这一问题,研究了沿弹道扰动引力的多项式拟合方法,并基于线性系统理论和弹道摄动思想推导了用于求解扰动引力对弹道助推段状态影响的完整解析表达式。同时考虑扰动引力影响与导弹视加速度之间的耦合特性,将扰动引力引起的视加速度偏差视为扰动引力影响的附加补偿项,并进行迭代修正。仿真结果表明:扰动引力拟合残差小于3×10~(-7)m/s~2,考虑耦合项修正的弹道误差传播解析模型计算残差减小为原有方法的1/3,计算时间仅为直接采用弹道积分求差法的1/10。     

高校学生宿舍楼火灾危险性的模糊综合评价

依据高校学生宿舍楼火灾危险性的影响因素,应用模糊识别理论构建了高校学生宿舍楼火灾危险性评价指标体系,并利用层次分析和多级模糊评价相结合的方法对某高校学生宿舍楼火灾危险性进行综合评价。研究表明:该方法的评估结果符合实际情况,且简便可行,具有较强的实际应用性。     

集对分析法在作战仿真结果分析中的应用研究

提出了集对分析法的概念,详细讨论了集对分析法对多指标问题的评估步骤、方法及特点.文章最后运用该方法对一个分队作战仿真实例进行了综合分析评估,证明了集对分析法简单、实用、有效.     

灰数兰彻斯特方程

为解决联合作战模拟中武器装备的作战能力评估问题,提出了基于打击力、机动力、信息力、防护力、保障力等的武器装备作战能力灰色层次分析模型,目的在于提供在联合作战模拟中,对武器装备的作战能力进行比较的算法。即从打击、机动、信息、防护、保障等来考虑武器装备的性能,采用灰色层次分析的方法,根据灰数的大小确定各类各对象的优劣,由此做出作战能力的合理判断,给出了实例及求解方案。最后,提出了不同灰类的总评估系数作为损耗方程的损耗系数的设想及其算例。     

建筑外装修及外保温系统的消防安全问题及对策

建筑外部装修及外保温系统的消防安全问题日益突出,结合实际中的建筑外部装修及外保温系统现状,分析了建筑外部装修及外保温系统对消防安全的影响,分析发现建筑外部装修及外保温系统的消防安全隐患大,需要给予足够的重视,并根据实际确定了相应的对策。     

Approximating nondominated sets in continuous multiobjective optimization problems

Many important problems in Operations Research and Statistics require the computation of nondominated (or Pareto or efficient) sets. This task may be currently undertaken efficiently for discrete sets of alternatives or for continuous sets under special and fairly tight structural conditions. Under more general continuous settings, parametric characterisations of the nondominated set, for example through convex combinations of the objective functions or ε‐constrained problems, or discretizations‐based approaches, pose several problems. In this paper, the lack of a general approach to approximate the nondominated set in continuous multiobjective problems is addressed. Our simulation‐based procedure only requires to sample from the set of alternatives and check whether an alternative dominates another. Stopping rules, efficient sampling schemes, and procedures to check for dominance are proposed. A continuous approximation to the nondominated set is obtained by fitting a surface through the points of a discrete approximation, using a local (robust) regression method. Other actions like clustering and projecting points onto the frontier are required in nonconvex feasible regions and nonconnected Pareto sets. In a sense, our method may be seen as an evolutionary algorithm with a variable population size. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.     

石油化工静电火灾原因及其防治对策

分析了石油化工生产中静电的危害,根据静电产生的原因、引起火灾爆炸的条件分析静电导致火灾或爆炸事故的原因,并提出消除静电和预防静电火灾的对策。