概率条件下雷区范围估计研究

为更正现有雷区范围估计算法因搜扫率处置不当而存在的矛盾与不足,研究了搜扫率条件下的雷区范围估计问题。分不规则雷区和规则雷线两种情况,依据极大似然估计的原理,推导出搜扫率条件下的雷区范围估计算法,并对改进算法与现有算法进行了分析比较和仿真示例验证。分析和示例表明新算法克服了现有算法的缺陷,能够更符合实际地解决雷区范围估计问题。     

基于随机Petri网的装备抢救抢修保障模型

通过建立一个基本的装备抢救抢修Petri网模型,把Petri网建模思想引入战时装备抢救抢修保障模型中,将实际系统中的实体和活动映射为模型系统中的库所和变迁,将装备抢救抢修保障排队论模型用随机Petri网进行描述。构建了一个完整的装甲团装备抢救抢修随机Petri网模型,利用软件包SPNP6.0对其进行模拟运行,通过对模型仿真数据的分析为装备保障的方案制定提供决策依据。     

控制不等式的改进

讨论了随机过程控制关系产生的不等式,对这个不等式给出了一个新系数,改进了以前的结果,并将其应用于局部平方可积鞅.     

Balancing a one‐way corridor capacity and safety‐oriented reliability: A stochastic optimization approach for metro train timetabling

In urban rail transit systems of large cities, the headway and following distance of successive trains have been compressed as much as possible to enhance the corridor capacity to satisfy extremely high passenger demand during peak hours. To prevent train collisions and ensure the safety of trains, a safe following distance of trains must be maintained. However, this requirement is subject to a series of complex factors, such as the uncertain train braking performance, train communication delay, and driver reaction time. In this paper, we propose a unified mathematical framework to analyze the safety‐oriented reliability of metro train timetables with different corridor capacities, that is, the train traffic density, and determine the most reliable train timetable for metro lines in an uncertain environment. By employing a space‐time network representation in the formulations, the reliability‐based train timetabling problem is formulated as a nonlinear stochastic programming model, in which we use 0‐1 variables to denote the time‐dependent velocity and position of all involved trains. Several reformulation techniques are developed to obtain an equivalent mixed integer programming model with quadratic constraints (MIQCP) that can be solved to optimality by some commercial solvers. To improve the computational efficiency of the MIQCP model, we develop a dual decomposition solution framework that decomposes the primal problem into several sets of subproblems by dualizing the coupling constraints across different samples. An exact dynamic programming combined with search space reduction strategies is also developed to solve the exact optimal solutions of these subproblems. Two sets of numerical experiments, which involve a relatively small‐scale case and a real‐world instance based on the operation data of the Beijing subway Changping Line are implemented to verify the effectiveness of the proposed approaches.     

对几种不同维数据融合方法的仿真对比研究

在多雷达系统组网对空情报处理中，不同的数据融合方法在融合精度、求解时间及计算量方面都有较大差异。为了验证不同融合方法的融合效果及系统处理时间和性能，分析了多雷达系统组网对不同维数据融合处理的映射法、升维法、分维法的融合框架和融合算法，并分别进行了计算机仿真，得出并分析了对比数据。仿真结果表明了分维法在数据融合中的优势。     

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     

考虑随机回放的卫星数传调度问题的一种求解方法

针对考虑随机回放的卫星数传调度问题,从置换空间到调度解空间的映射方法和置换空间的搜索算法两方面进行了研究.提出了一种时间窗优先的置换序列映射算法,并证明该映射算法可以将置换序列映射到调度解空间上的最优解.提出了一种遗传随机搜索算法,基于有记忆功能的随机邻域搜索,在置换空间上搜索产生优化调度的置换序列.仿真计算表明,遗传随机搜索算法可以增强遗传算法的局部搜索能力,在搜索结果上平均获得了2.72%的改进.