用故障树分析法排除柴油机监控系统故障

对某型舰艇柴油机监控系统运行中发现的三个故障现象,应用故障树分析法,构筑相应故障树,在此基础上进行逐项测试检查,最终完成了故障定位,修理后成功地排除了所有故障.     

Life in the “Gray Zone”: observations for contemporary strategists

The term “Gray Zone” is gaining in popularity as a way of describing contemporary security challenges. This article describes the “short-of-war” strategies – the fait accompli, proxy warfare, and the exploitation of ambiguous deterrence situations, i.e. “salami tactics” – that are captured by the term and offers several explanations for why state and non-state actors are drawn to these strategies. The analysis highlights why defense postures based on deterrence are especially vulnerable to the short-of-war strategies that populate the “Gray Zone.” The article concludes by suggesting how defense officials might adapt defense policies to life in the “Gray Zone.”     

软件可测性评估

介绍了现有的软件可测性评估方法,继而提出了基于程序结构的软件可测性评估方法,该方法充分考虑了软件的失效机理,针对测试对象的不同特点,给出了面向控制流的软件故障执行的概率、数据状态感染的概率及以变量的定值-引用为基础的被感染数据状态传播到输出的概率等估计方案,在此基础上,进行了软件可测性的评估.     

故障传播有向图在地面电源故障诊断的应用

基于图论的故障诊断方法能够有效地缩小故障源的搜索范围,在最短的时间内找到真正产生故障的部件。采用故障传播有向图的方法对某飞行器地面电源故障诊断算法进行了研究,针对该飞行器地面电源的物理结构及相关的电气特性得到其故障传播有向图,并经过一些运算后将有向图进行了分层重构,最后利用故障定位算法模拟了故障定位的过程,得到了很好的效果。     

一种改进的SIR粒子滤波方法

SIR粒子滤波算法在重采样无法进行时可能失效,详细分析了算法失效的原因,并针对此问题提出了基于PSO的改进方法,该方法利用PSO的智能寻优机制引导重要性抽样的粒子移向高似然区,从而确保重采样过程的顺利进行。仿真试验表明,提出的改进方法可以有效解决SIR算法因重采样无法进行而导致的失效问题。     

Bounding the optimal burn‐in time for a system with two types of failure

Burn‐in is a widely used method to improve the quality of products or systems after they have been produced. In this paper, we consider the problem of determining bounds to the optimal burn‐in time and optimal replacement policy maximizing the steady state availability of a repairable system. It is assumed that two types of system failures may occur: One is Type I failure (minor failure), which can be removed by a minimal repair, and the other is Type II failure (catastrophic failure), which can be removed only by a complete repair. Assuming that the underlying lifetime distribution of the system has a bathtub‐shaped failure rate function, upper and lower bounds for the optimal burn‐in time are provided. Furthermore, some other applications of optimal burn‐in are also considered. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004     

动态系统可靠性分析的新概念

传统可靠性分析的概念只能描述静态逻辑关系,不能满足现代复杂动态系统可靠性分析的需要。在给出动态系统状态空间结构和结构函数的基础上,提出失效序列和失效丛的概念描述动态系统的故障模式,这一概念扩展了传统可靠性分析的概念,将割集、蕴含集等作为其在静态情形的特例。给出动态系统部件的概率重要度、结构重要度以及关键重要度的概念,用实例对提出的有关概念进行了说明。     

Heart analytics: Analytical modeling of cardiovascular care

Cardiovascular diseases (CVDs) are the leading cause of death and disability both in the United States and worldwide. Despite high morbidity, mortality, and cost in the United States and global healthcare systems, cardiovascular care has been understudied in the healthcare operations management literature. In this paper, we identify research opportunities for healthcare operations management scholars to aid in improving cardiovascular care. We focus on three burdensome conditions, including (1) coronary artery disease, (2) stroke, and (3) heart failure, which, collectively, lead to the vast majority of CVD‐caused mortality and disability. For each condition, we characterize a typical patient's journey in receiving cardiovascular care, elucidating key challenges in improving care and outlining research questions for healthcare operations management scholars. We close with a reference to new research opportunities that emerge as artificial intelligence is likely to transform much of cardiovascular care.     

自修复飞控系统故障检测与隔离软件系统

介绍了一个自修复飞行控制系统故障检测和隔离实时工程软件系统,该系统按照软件工程规范、采用等价空间法和残差向量的概率信息融合法研制和开发,不仅能对飞行控制系统的突变故障——作动器卡死故障和控制舵面损伤故障进行实时检测和隔离,而且具有良好的用户界面。仿真研究表明该软件系统具有良好的鲁棒性和实时性。     

A comparative study of three tool replacement/operation sequencing strategies in a flexible manufacturing system

This paper studies three tool replacement/operation sequencing strategies for a flexible manufacturing system over a finite time horizon: (1) failure replacement—replace the tool only upon failure, (2) optimal preventive tool replacement for a fixed sequence of operations, and (3) joint scheduling of the optimal preventive tool replacement times and the optimal sequence of operations. Stochastic dynamic decision models are used for strategies 2 and 3. The optimization criterion for strategies 2 and 3 is the minimization of the total expected cost over the finite time horizon. We will show through numerical studies that, with the same amount of information, the total expected costs can be reduced considerably by choosing an optimal strategy. Our conclusion is that in flexible manufacturing, optimal tool replacement and optimal operations sequencing are not separate issues. They should be considered jointly to minimize the expected total cost. © 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 479–499, 2000