Global planning of accelerated degradation tests based on exponential dispersion degradation models

The accelerated degradation test (ADT) is an efficient tool for assessing the lifetime information of highly reliable products. However, conducting an ADT is very expensive. Therefore, how to conduct a cost-constrained ADT plan is a great challenging issue for reliability analysts. By taking the experimental cost into consideration, this paper proposes a semi-analytical procedure to determine the total sample size, testing stress levels, the measurement frequencies, and the number of measurements (within a degradation path) globally under a class of exponential dispersion degradation models. The proposed method is also extended to determine the global planning of a three-level compromise plan. The advantage of the proposed method not only provides better design insights for conducting an ADT plan, but also provides an efficient algorithm to obtain a cost-constrained ADT plan, compared with conventional optimal plans by grid search algorithms.     

Selecting review periods for a coordinated multi‐item inventory model with staggered deliveries

Consider an N‐item, periodic review, infinite‐horizon, undiscounted, inventory model with stochastic demands, proportional holding and shortage costs, and full backlogging. For 1 ≤ j ≤ N, orders for item j can arrive in every period, and the cost of receiving them is negligible (as in a JIT setting). Every T_j periods, one reviews the current stock level of item j and decides on deliveries for each of the next T_j periods, thus incurring an item‐by‐item fixed cost k_j. There is also a joint fixed cost whenever any item is reviewed. The problem is to find review periods T₁, T₂, …, T_N and an ordering policy satisfying the average cost criterion. The current article builds on earlier results for the single‐item case. We prove an optimal policy exists, give conditions where it has a simple form, and develop a branch and bound algorithm for its computation. We also provide two heuristic policies with O(N) computational requirements. Computational experiments indicate that the branch and bound algorithm can handle normal demand problems with N ≤ 10 and that both heuristics do well for a wide variety of problems with N ranging from 2 to 200; moreover, the performance of our heuristics seems insensitive to N. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48:430–449, 2001     

一类对固定目标的集群搜寻对策问题及求解

利用集群搜索对策的理论与方法 ,建立了集群对固定目标的一类搜索对策模型 ,给出了集群的ε -最优搜寻策略 ,并考虑了其在搜索过程中的应用     

导弹对抗离散数学模型

针对现代非接触战争的特点,用数学方法研究导弹对抗模型问题,针对作战的不同目的和要求,建立两个导弹对抗的非线性规划数学模型,对模型求解设计了近似方法,该方法把上述非线性规划模型化为多个线性规划模型进行求解.对一类较简单的特殊情况进行了仔细分析,得到了分析解.最后指出该方法如何应用于动态实时优化决策.本文的方法可用来预测和评估导弹对抗的效果,为作战实时优化决策提供参考.     

Optimality of the greedy shooting strategy in the presence of incomplete damage information

Consider a situation where a single shooter engages, sequentially, a cluster of targets that may vary in terms of vulnerability and value or worth. Following the shooting of a round of fire at a certain target, the latter may either be killed or remain alive. We assume neither partial nor cumulative damage. If the target is killed, there is a possibility that the shooter is not aware of that fact and may keep on engaging that target. If the shooter recognizes a killed target as such, then this target is considered to be evidently killed. If the objective is to maximize the weighted expected number of killed targets, where the weight reflects the value of a target, then it is shown that a certain type of a shooting strategy, called a Greedy Strategy, is optimal under the general assumption that the more a target is engaged, but still not evidently killed, the less is the probability that the next round will be effective. If all weights are equal, then the greedy shooting strategy calls to engage, at each round, the least previously engaged target that is not evidently killed. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44: 613–622, 1997     

基于高斯伪谱法的弹道跟踪制导律

针对拦截临近空间高超声速飞行器的弹道跟踪过程,设计了一种基于高斯伪谱法的跟踪制导律。为了对标称弹道进行精确跟踪,基于线性二次型跟踪问题,应用最优控制理论推导最优解的充要条件,得到带时变增益的线性状态反馈控制量的表达式;基于高斯伪谱法,在离散的勒让德-高斯(LG)点上利用标称弹道数据计算差分矩阵和系数矩阵,求得状态扰动反馈控制律。仿真结果表明,该方法能够快速、有效的消除跟踪误差,满足在线实施要求。     

基于模糊基函数网络的机械臂免模型输出反馈PD控制

针对无速度信息的机械臂轨迹跟踪控制问题,提出了一种带观测器的机械臂免模型模糊基函数网络输出反馈PD控制。所设计的模糊基函数网络被用来估计关节速度,并同时用来补偿系统的未知不确定。网络的权值及参数调整采用混合算法,且能够在线自适应实时调整,不需要离线学习阶段。所提出的观测器及控制器均不需要任何的机械臂动态模型(包括惯性矩阵逆),并通过引入PD控制使整个方案更易工程实现。基于Lyapunov理论证明了整个闭环系统一致最终有界。两关节机械臂试验结果进一步证明了这种基于观测器的反馈控制算法的有效性。     

Equivalent accelerated life testing plans for log‐location‐scale distributions

Accelerated life testing (ALT) is widely used to determine the failure time distribution of a product and the associated life‐stress relationship in order to predict the product's reliability under normal operating conditions. Many types of stress loadings such as constant‐stress, step‐stress and cyclic‐stress can be utilized when conducting ALT. Extensive research has been conducted on the analysis of ALT data obtained under a specified stress loading. However, the equivalency of ALT experiments involving different stress loadings has not been investigated. In this article, a log‐location‐scale distribution under Type I censoring is considered in planning ALT. An idea is provided for the equivalency of various ALT plans involving different stress loadings. Based on this idea, general equivalent ALT plans and some special types of equivalent ALT plans are explored. For demonstration, a constant‐stress ALT and a ramp‐stress ALT for miniature lamps are presented and their equivalency is investigated. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

关于在公安现役部队推行全面预算管理的几点思考

对现阶段公安现役部队全面预算管理现状和面临的问题进行了分析,从确定部队战略目标,党委重视和全员参与,构建全面预算管理组织结构及制度体系,全面预算的编制、控制、调整及考评等几个方面提出了有效实施全面预算管理的思路和具体措施。     

基于状态观测器的混沌系统鲁棒同步设计

研究了在有界干扰情况下一类非线性反馈混沌系统的鲁棒同步状态观测器设计问题。基于Sylvester矩阵方程的参数化解,将非线性反馈混沌系统的鲁棒同步状态观测器设计问题转化为带有约束条件的优化问题,通过解决该优化问题得到鲁棒同步状态观测器的增益矩阵,从而达到了干扰信号解耦目的。数值算例及其仿真结果表明:该非线性反馈混沌系统的鲁棒同步状态观测器的设计方法是简单有效的。