A nonparametric Bayes approach to decide system burn-in time

Burn-in is the preconditioning of assemblies and the accelerated power-on tests performed on equipment subject to temperature, vibration, voltage, radiation, load, corrosion, and humidity. Burn-in techniques are widely applied to integrated circuits (IC) to enhance the component and system reliability. However, reliability prediction by burn-in at the component level, such as the one using the military (e.g., MIL-STD-280A, 756B, 217E [23–25]) and the industrial standards (e.g., the JEDEC standards), is usually not consistent with the field observations. Here, we propose system burn-in, which can remove many of the residual defects left from component and subsystem burn-in (Chien and Kuo [6]). A nonparametric model is considered because 1) the system configuration is usually very complicated, 2) the components in the system have different failure mechanisms, and 3) there is no good model for modeling incompatibility among components and subsystems (Chien and Kuo [5]; Kuo [16]). Since the cost of testing a system is high and, thus, only small samples are available, a Bayesian nonparametric approach is proposed to determine the system burn-in time. A case study using the proposed approach on MCM ASIC's shows that our model can be applied in the cases where 1) the tests and the samples are expensive, and 2) the records of previous generation of the products can provide information on the failure rate of the system under investigation. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44: 655–671, 1997     

Some new results on the preservation of the NBUE and NWUE aging classes under the formation of coherent systems

We consider the classical problem of whether certain classes of lifetime distributions are preserved under the formation of coherent systems. Under the assumption of independent and identically distributed (i.i.d.) component lifetimes, we consider the NBUE (new better than used in expectation) and NWUE (new worse than used in expectation) classes. First, a necessary condition for a coherent system to preserve the NBUE class is given. Sufficient conditions are then obtained for systems satisfying this necessary condition. The sufficient conditions are satisfied for a collection of systems which includes all parallel systems, but the collection is shown to be strictly larger. We also prove that no coherent system preserves the NWUE class. As byproducts of our study, we obtain the following results for the case of i.i.d. component lifetimes: (a) the DFR (decreasing failure rate) class is preserved by no coherent systems other than series systems, and (b) the IMRL (increasing mean residual life) class is not preserved by any coherent systems. Generalizations to the case of dependent component lifetimes are briefly discussed.     

Unsolved murders and the investigative failures of the Nigerian police force: Security and sociopolitical implications

This article focuses on the systemic failures of the Nigerian police force to unravel the mysteries surrounding homicides in the country, along with the security, social and political implications of the ongoing trend. The article draws on documented pieces of evidence of high-profile murders, along with the causes of the upsurge in murder incidences and the inhibitive factors relating to the investigative procedures of the police. The suitability of the theory of subaltern realism and the concept of third-world security predicaments in explaining the peculiarities of Nigeria’s internal security challenges is examined, along with the problems of the legitimacy of political regimes and weak borders. There is a need for the National Assembly of Nigeria to exercise its constituted powers in reawakening and supervising investigations into dormant cases of murder through its committees on police affairs, public safety and national security. The police should check its organisational failures, which may be related to using the wrong investigative approaches, low levels of information, limited resources, corrupt practices, and pressure to obtain quick results.     

基于平衡计分卡的武器装备维修绩效评价指标体系构建

武器装备维修是武器装备维修保障的重要内容,加强装备维修绩效评价,建立科学规范的绩效评价指标体系,对深入推进装备维修工作健康发展将发挥积极作用。以平衡计分卡为研究手段,运用"5M1E"分析法,从一个内核和四个维度出发,分析武器装备维修绩效评价的影响因素,据此建立评价指标体系,并应用于装备维修管理实践,为有效提高装备维修保障效益提供有益借鉴。     

关于军民融合大交通体系建设的几点思考

党的十九大报告把军民融合发展战略作为七大国家战略之一,明确提出要"更加注重军民融合"。必须将交通领域军民融合视作整个军民融合深度发展的重要突破口,建设军民融合大交通体系。提出以新形势下军事战略方针为统揽,以军民深度融合为途径,聚焦保障军队打赢,大力推进民用交通设施工具贯彻要求;依托国家路网基础,大力推进军地交通运输网络统筹纳入;强化应战应急一体,大力推进各种交通力量建设互补衔接;着眼战略投送能力,大力推进军民交通物流体系有机结合。     

基于大数据的战区联合作战装备保障决策

大数据技术在决策领域的不断应用,将给装备保障决策方式带来重大变革。本文研究基于大数据的战区联合作战装备保障决策问题,提升信息化条件下装备保障准确、高效的决策方式等方面发挥重大作用。阐述了大数据的基本内涵,在决策领域的应用价值。通过系统推理的方法对战区联合作战装备保障决策的分析,提出基于大数据的战区联合作战装备保障决策基本构想,画出科学决策过程示意图,构建大数据战区联合作战装备保障辅助决策系统。结合研究大数据在战区联合作战装备保障决策领域的现实情况,提出相对应的措施建议。     

高效率机动部署航空武器靶场关键技术和应用

为用户设计了一个航空武器试验靶场,具备空空、空地和地空导弹试验能力,可机动部署,具有易于运行和运维代价低的特点。靶场由载机遥测系统、测量雷达、光电跟踪系统、微波和光纤通信系统、靶机遥测站、指挥控制等6个子系统构成;指挥控制子系统之外的5个子系统均使用国产成熟产品。在总体方案和指挥控制子系统设计中,对互联集成方案、机动部署、试验航线设计和发布、自动化领航、自动化指挥决策等5项关键技术进行了着重优化。在实际应用中,全靶场运行仅需20多成员(不含飞行和机场机务人员),3天内完成新试验场部署和联调,对作战部队飞行员进行5架次航线训练后即进行实弹试验,2天内完成多发中程拦截和近距格斗空空导弹试验。     

军事攻防中的多属性资源分配对策模型

针对资源受限情形下的两阶段攻防资源分配问题,提出一种基于多属性决策的资源分配对策模型。防守者首先将有限的防护资源分配到不同的目标上,继而进攻者选择一种威胁组合方式对目标实施打击。基于博弈论相关知识,模型的求解结果可以使防守者最小化自身损失,使进攻者最大化进攻收益。同时,针对模型的特点,给出了一些推论和证明。通过一个示例验证了模型的合理性以及相关推论的准确性,能够为攻、防双方规划决策提供辅助支持。     

Aggregating courier deliveries

We consider the problem of efficiently scheduling deliveries by an uncapacitated courier from a central location under online arrivals. We consider both adversary‐controlled and Poisson arrival processes. In the adversarial setting we provide a randomized (3βΔ/2δ ? 1) ‐competitive algorithm, where β is the approximation ratio of the traveling salesman problem, δ is the minimum distance between the central location and any customer, and Δ is the length of the optimal traveling salesman tour overall customer locations and the central location. We provide instances showing that this analysis is tight. We also prove a 1 + 0.271Δ/δ lower‐bound on the competitive ratio of any algorithm in this setting. In the Poisson setting, we relax our assumption of deterministic travel times by assuming that travel times are distributed with a mean equal to the excursion length. We prove that optimal policies in this setting follow a threshold structure and describe this structure. For the half‐line metric space we bound the performance of the randomized algorithm in the Poisson setting, and show through numerical experiments that the performance of the algorithm is often much better than this bound.     

重塑军队作战力量体系的几点思考

作战力量体系是一个国家军事力量体系的核心组成部分。近些年通过深化国防和军队改革,我军军事力量体系宏观上发生了脱胎换骨的变化,接下来到了对作战力量体系进行重塑的攻坚阶段,本文结合当前作战力量体系发展的一些特点和建设存在的短板,提出了重塑我军作战力量体系的决策建议。 