Bayesian sampling plans for exponential distributions with interval censored samples

This article studies the problem of designing Bayesian sampling plans (BSP) with interval censored samples. First, an algorithm for deriving the conventional BSP is proposed. The BSP is shown to possess some monotonicity. Based on the BSP and using the property of monotonicity, a new sampling plan modified by the curtailment procedure is proposed. The resulting curtailed Bayesian sampling plan (CBSP) can reduce the duration time of life test experiment, and it is optimal in the sense that its associated Bayes risk is smaller than the Bayes risk of the BSP if the cost of the duration time of life test experiment is considered. A numerical example to compute the Bayes risks of BSP and CBSP and related quantities is given. Also, a Monte Carlo simulation study is performed to illustrate the performance of the CBSP compared with the BSP. The simulation results demonstrate that our proposed CBSP has better performance because it has smaller risk. The CBSP is recommended. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 604–616, 2015     

序降应力加速寿命试验(下)——优化设计篇

如何设计试验方案使试验评估结果更准确、试验代价更小,是序降应力加速寿命试验应用中面临的一个重要问题。以试验评估精度和试验代价共同需求为背景,建立一类新的基于加权系数的优化目标函数。为解决仿真优化设计过程中的计算量问题,在深入分析目标函数性质基础上,提出一种新的优化设计法——正交搜索法。与优化设计过程的全局搜索法不同,该方法能够逐次缩小目标函数值,快速逼近最优试验方案。最后通过仿真算例验证了新方法的正确性和高效性。     

基于Vague集极值记分函数的装甲分队目标威胁评估

为了快速准确地对装甲分队作战单元面临的目标进行威胁度判断,提高信息化装甲分队作战辅助决策水平,建立了基于Vague集的极值记分函数评估模型,且构造了适合威胁评估的记分函数。实例分析表明,该模型可有效地完成目标威胁评估与排序,为分队火力优化控制提供重要数据支持。     

一种钢管焊接结构焊接节点损伤识别的新方法

采用端部半刚性连接梁单元模型进行模拟焊接节点的损伤,并基于应变模态理论,提出了一种焊接节点损伤识别两步法。第一步,先整体测量结构的位移模态并推导出应变模态,然后采用改进后的目标函数,通过信赖域优化算法对损伤节点位置进行准确判定;第二步,采用提出的杆端应变模态变化比指标,实现焊接节点损伤程度的精确识别。经工程实例的数值仿真及试验分析,验证了该方法的有效性及优越性,为解决这类大型焊接结构焊接节点的损伤识别问题提供了新思路。     

气浮箱型结构纵荡运动水动力系数解析研究

基于二维微幅波理论,采用特征函数展开和匹配渐进法建立了气浮箱型结构纵荡运动的解析解,将Matlab程序计算结果与MOSES数值模拟结果进行了对比分析,验证了程序的合理性;进而对不同吃水、不同水深下结构纵荡运动的附加质量系数和阻尼系数的幅频变化规律进行了研究。结果表明:由于未考虑结构内部气体的可压缩性,数值模拟结果大于程序计算结果,MOSES计算结果偏安全;在一定频率区段上,吃水的增加对结构附加质量系数和阻尼系数有显著影响;随着水深吃水比的增加,结构的附加质量系数和阻尼系数呈增大趋势,只有在圆频率为0.65~0.9 rad/s时呈减小趋势,而阻尼系数则呈增大趋势。     

面向蛋白质功能预测中有向无环图标记结构的多示例多标记学习

在多示例多标记学习问题中,标记之间往往是相互关联的,其中有向无环图结构是一种常见的层次关联结构,可见于蛋白质的基因本体学生物学功能预测的应用场景中。针对其标记间的有向无环图结构,提出了一种新的多示例多标记学习算法。算法从原始数据的特征空间训练出所有标记共享的低维子空间,通过随机梯度下降方法来降低模型排序损失,并融入标记间有向无环图结构关系对预测标记进行优化。将该算法应用于多个数据集的蛋白质功能预测中,实验结果表明,该算法具有更高的效率及预测性能。     

带局部交流函数及自由意志的单领导Cucker-Smale模型的渐近集群分析

为研究集群的形成与否和半径大小之间的关系,主要考虑了具有单个领导的一般等级结构及其领导者速度不变的Cucker-Smale模型。探讨了自由意志对集群产生的影响,通过证明可以给出半径有下界的充分条件(下界和速度差、粒子数、通信强度等有关)。当半径大于下界时,会产生集群。通过MATLAB数值仿真验证了相关结论。     

Two novel critical shock models based on Markov renewal processes

In this paper, we investigate systems subject to random shocks that are classified into critical and noncritical categories, and develop two novel critical shock models. Classical extreme shock models and run shock models are special cases of our developed models. The system fails when the total number of critical shocks reaches a predetermined threshold, or when the system stays in an environment that induces critical shocks for a preset threshold time, corresponding to failure mechanisms of the developed two critical shock models respectively. Markov renewal processes are employed to capture the magnitude and interarrival time dependency of environment-induced shocks. Explicit formulas for systems under the two critical shock models are derived, including the reliability function, the mean time to failure and so on. Furthermore, the two critical shock models are extended to the random threshold case and the integrated case where formulas of the reliability indexes of the systems are provided. Finally, a case study of a lithium-ion battery system is conducted to illustrate the proposed models and the obtained results.     

基于险度函数的装备供应链库存风险损失度量

目前,对供应链库存风险损失的定量研究比较少,而定量研究中鲜有对风险偏好变化问题的研究,因此首先分析了各种风险度量方法,通过比较采用了险度函数作为对装备供应链风险损失的度量方法;然后,结合装备供应链实际,提出了定常风险偏好特性险度函数和可变风险偏好特性险度函数的适用范围,以及装备供应链库存风险损失度量的损失水平值,并给出了装备供应链库存风险损失度量函数;最后,通过算例进行了验证.实验结果表明:行为人的不同风险偏好特性会对同一事态产生不同的预判,进而可能影响对风险的决策,这是符合客观现实的.     

SDI,NATO, and the Social Composition Function

The strategic defense initiative (SDI) intends to renew the leadership of the USA on the western alliance. The initiative takes place in a period when a summation technology prevails for the aggregation of contributions of NATO allies. We investigate if SDI induces a shift in Hirshleifer’s social composition function. Panel data tests over the period 1970–1990 do not confirm any break toward a best-shot aggregator. SDI does not alter the core of deterrence. It is indeed a public good at the US level but not at the NATO level, where, it is one of the joint products of the alliance. We also investigate the lessons to be drawn for the current debates on ballistic defense.