小子样条件下可靠性试验信息的融合方法

小子样条件下,不同状态的多源信息融合是可靠性工程领域的一个热门问题。综述了小子样条件下可靠性试验信息的融合方法。在一定的假设条件之下,利用分离可交换量模型对不同环境下的可靠性信息融合方法进行了研究,仿真算例说明这种融合方法充分利用了信息,评估结论更为合理。     

基于模糊层次分析法的航天测控方案优选决策

分析了航天测控任务重要度的影响因素,运用模糊层次分析法研究了航天测控任务方案的优选决策问题,详细分析了方案重要度排序的计算步骤,并通过实例计算证明了方法的简单可行性,该方法在处理航天测控冲突时有一定的应用价值。     

基于模糊AHP法的舰艇威胁能力评估

舰艇平台的威胁能力评估是海战场态势评估的基础。依据舰艇平台搭载的武器装备,建立舰艇威胁能力评估的指标体系,采用层次分析法确定各个指标的权重,构建基于模糊综合评判法的舰艇威胁能力评估模型。基于此模型,对阿利.伯克级I和II型导弹驱逐舰威胁能力进行了评估,实验表明方法合理。     

基于GO法的多阶段共因失效任务系统可靠性评估

为了解决部件阶段依赖性与共因失效给系统可靠性分析带来的复杂性,针对多阶段共因失效任务系统,结合GO法易于处理有时序、含共因失效系统可靠性分析的特点,首先,将前一阶段的输出信号作为后一阶段的输入信号,建模时首尾连接各阶段模型,建立整个任务系统的隐性GO模型;其次,在进行各信号流状态组合运算时,融入阶段代数处理部件的阶段依赖性;再次,用隐性共因失效分析,将共因失效对系统的影响在状态组合的定量分析中表达出来,得到所需系统可靠性指标;最后,与基于二元决策图的算法进行对比验证。结果表明:GO法可以简捷、准确地处理多阶段共因失效任务系统可靠性评估问题。     

基于IDEF3的部队装备中修业务流程优化重组

以IDEF3为工具描述了部队装备中修业务流程,分析了流程中存在的问题,通过采用基于状态的维修方式、无损检测先进技术手段、共享维修保障信息和调整器材发放审批权限等方法,对部队现行装备中修业务流程进行了优化,可有效解决装备维修过剩、维修不足、维修资源浪费和维修周期过长等问题．     

基于RBF网络加速模型的可靠性评估

在可靠性加速试验中,由于各种不同的应力引起的失效机理不一样,不同应力之间可能还存在着相互耦合作用,要将它们和寿命结合,找出一个能真实描述客观情况的加速模型是相当困难的,仅仅依据有限的试验数据建立产品的加速模型存在很大难度和风险,为此提出了一种基于RBF网络加速模型的可靠性评估方法．该方法将加速寿命试验中的加速应力和可靠度作为训练网络的输入向量,相应的时间作为目标向量对网络进行训练,根据网络收敛速和误差精度等情况调整隐含层单元个数,直至得到最优的网络．最后,以实例说明了该方法的有效性和实用性．     

基于可执行模型架构的成像侦察卫星系统建模与仿真

成像侦察卫星系统内部关系复杂、任务需求种类较多,利用基于町执行模型架构的系统工程对其进行建模研究,可以有效地实现从模型到仿真的综合集成．通过研究可执行模型架构理论,集成UPDM与成像侦察卫星系统功能模型,对成像侦察卫星系统进行了建模与仿真,验证了可执行模型架构的有效性与实用性．     

Evaluating cost and reliability integrated performance of stochastic logistics systems

The significance of integrating reliability into logistics performance has been established [The Logistics Performance Index and Its Indicators, World Bank International Trade and Transport Departments, (2010)]. Hence, as a response to the work by the World Bank, the present article aims to evaluate the performance index R_b,d of logistics systems as the probability that a specified demand d can be distributed successfully through multistate arc capacities from the source to the destination under the constraint that the total distribution cost should not exceed the cost limitation b. This article provides a pioneering approach for a straightforward computation of the performance index R_b,d. The proposed algorithm is a hybrid between the polynomial time capacity‐scaling algorithm, which was presented by Edmonds and Karp [JACM 19 (1972)], and the decomposition algorithm, which was presented by Jane and Laih [IEEE (2008)]. Currently, the proposed approach is the only algorithm that can directly compute R_b,d. An illustration of the proposed algorithm is presented. The results of the computational experiments indicate that the presented algorithm outperforms existing algorithms. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

Service design at diagnostic service centers

We study a service design problem in diagnostic service centers, call centers that provide medical advice to patients over the phone about what the appropriate course of action is, based on the caller's symptoms. Due to the tension between increased diagnostic accuracy and the increase in waiting times more in‐depth service requires, managers face a difficult decision in determining the optimal service depth to guide the diagnostic process. The specific problem we consider models the situation when the capacity (staffing level) at the center is fixed, and when the callers have both congestion‐ and noncongestion‐related costs relating to their call. We develop a queueing model incorporating these features and find that the optimal service depth can take one of two different structures, depending on factors such as the nurses' skill level and the maximum potential demand. Sensitivity analyses of the two optimal structures show that they are quite different. In some situations, it may (or may not) be optimal for the manager to try to expand the demand at the center, and increasing skill level may (or may not) increase congestion. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

温度对锂硫电池放电过程的影响

为深入研究液相扩散过程对锂硫电池放电过程的影响,采用充放电测试、循环伏安测试了不同温度下锂硫电池的电化学性能,采用电子扫描显微镜观察分析了不同温度下放电后的正极形貌.实验结果表明,温度降低引起电解液粘度增加,离子在电解液中的扩散系数降低;当温度低于10℃时,锂硫电池的放电性能明显恶化,低放电平台容量的降低是电池性能恶化的主要原因.循环伏安测试分析表明,锂硫电池的低放电平台是扩散控制过程,受温度影响较大.离子在电解液中的扩散过程受限引起碳骨架的钝化,进而造成低放电平台活性物质未充分反应,这是锂硫电池放电过程受温度影响的主要原因.