Dynamic signatures and their use in comparing the reliability of new and used systems

The signature of a system with independent and identically distributed (i.i.d.) component lifetimes is a vector whose ith element is the probability that the ith component failure is fatal to the system. System signatures have been found to be quite useful tools in the study and comparison of engineered systems. In this article, the theory of system signatures is extended to versions of signatures applicable in dynamic reliability settings. It is shown that, when a working used system is inspected at time t and it is noted that precisely k failures have occurred, the vector s [0,1]^n‐k whose jth element is the probability that the (k + j)th component failure is fatal to the system, for j = 1,2,2026;,n ‐ k, is a distribution‐free measure of the design of the residual system. Next, known representation and preservation theorems for system signatures are generalized to dynamic versions. Two additional applications of dynamic signatures are studied in detail. The well‐known “new better than used” (NBU) property of aging systems is extended to a uniform (UNBU) version, which compares systems when new and when used, conditional on the known number of failures. Sufficient conditions are given for a system to have the UNBU property. The application of dynamic signatures to the engineering practice of “burn‐in” is also treated. Specifically, we consider the comparison of new systems with working used systems burned‐in to a given ordered component failure time. In a reliability economics framework, we illustrate how one might compare a new system to one successfully burned‐in to the kth component failure, and we identify circumstances in which burn‐in is inferior (or is superior) to the fielding of a new system. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009     

贪心遗传算法解决一般武器-目标分配问题

一般武器-目标分配问题,是使武器发挥最大效能而使目标遭受最大毁伤的最优化问题.遗传算法广泛用于解决最优化问题.提出一种具有贪心优化机制的局部搜索方法,以提高遗传算法的搜索效率,从而迅速找到全局最优解.应用于炮兵武器-目标分配问题的仿真试验结果表明,此算法比现有的其他搜寻算法具有更好的求解效率.     

消防中介机构法制建设问题研究

消防中介机构法制建设还存在很多问题，立法滞后，执法不严，必须加强法制建设，促进消防中介机构规范运行，以利于消防中介机构的健康发展。     

防空火控系统火力分配的多目标优化研究

在防空火控系统的研究中,如何充分发挥火力单元的作战效能,使来袭目标遭受最大的毁伤,是火力分配研究的一个关键问题.通过对防空火控系统的分析,给出了防空火控系统火力分配的问题描述,并建立了基于指派问题的火力分配数学模型.提出了威胁度计算的改进方法.在使防空高炮群对威胁度大的目标造成大的毁伤分配准则下,研究了利用匈牙利法求解指派问题时的具体方法.经仿真验证,此火力分配方法合理、有效.     

复杂电磁环境下搜索雷达探测概率仿真分析

为了具体分析复杂电磁环境对舰载搜索雷达的影响,针对搜索雷达干扰方式的数学模型,从研究搜索雷达探测概率的角度建立了作战效能模型.以这些数学模型为基础和依据,对海军作战仿真系统中,复杂电磁环境下舰载警戒搜索雷达探测概率进行了多次定量仿真计算,给出了主要数据结果.仿真计算结果与理论值基本吻合,证明仿真计算的结果是可靠的,能够反映复杂电磁环境对搜索雷达探测概率的实际影响.     

复杂电磁环境舰艇电子对抗仿真系统研究

针对目前舰艇电子对抗装备作战效能分析、作战使用方法研究和训练平台实用性不强的现状，采用复杂电磁环境生成技术，运用电子对抗作战使用理论，结合系列研练电子对抗反导积累相关数据，建立电子对抗仿真模型，实现仿真系统控制、复杂电磁环境接收与生成、三维海战场环境仿真显示、多型电子对抗显控界面仿真、舰艇电子对抗作战效能评估、舰艇电子对抗仿真训练成绩评定等功能，研制贴近实际的复杂电磁环境水面舰艇电子对抗装备作战运用仿真系统，以充分发挥舰艇电子对抗装备的作战潜能。     

支持向量顺序回归机的线性规划算法

支持向量顺序回归机是标准支持向量分类机的一个推广，它是一个凸的二次规划问题。本文根据l1范数与l2范数等价关系和优化问题的对偶原理，把凸的二次规划转化成线性规划。由此提了支持向量顺序回归机的线性规划算法，进一步用数值实验验证了此算法的可行性和有效性。并与支持向量顺序回归机相比，它的运行时间缩短了，而且误差i不超过支持向量顺序回归机；     

型号研制与产品数据管理

介绍了产品数据管理(PDM)的概念和基本功能,结合当前型号研制的特点和计算机信息技术应用的状况、发展,研究了型号研制产品数据管理的需求、功能及实施,为当前型号研制依靠CIMS技术实现产品数据管理提出了8条基本原则。     

平流层飞艇空间控制作战样式分析*

临近空间是未来作战的制高点之一,在分析了临近空间作战特点的基础上,建立了平流层飞艇编队作战模型,通过研究飞艇的信息对抗能力、防御能力及武器性能,表明激光武器比导弹更适合于平流层飞艇的临近空间作战,干扰通信系统比干扰侦察系统对作战结果的影响更大,采取一定的防御措施也不能对平流层飞艇的损失率产生较大影响.     

Does Military Spending Nonlinearly Affect Economic Growth in South Africa?

Using annual data collected from 1988 to 2015, this study provides evidence of a non-linear relationship between military spending, economic growth and other growth determinants for the South African economy. The empirical study is based on estimates of a logistic smooth transition regression (LSTR) model and our empirical results point to an inverted U-shaped relationship between military spending and economic growth for the data. Furthermore, our empirical results suggest that the current levels of military spending, as a component of total government expenditure, are too high in the South African economy and need to be transferred towards more productive non-military expenditure in order to improve the performance of economic growth and other growth determinants.