基于Petri网的维修过程建模仿真方法研究

通过引进老化令牌对随机Petri网进行理论扩展,提出了一种基于老化令牌的随机Petri网（SPNAT）的维修过程建模与仿真方法,有效地解决了传统维修性建模方法在多个失效率不同的部件系统所存在的建模复杂和求解困难等问题,并通过实例验证了该建模方法的有效性和优越性。     

基于灰色层次分析法的侦察装备效能评估

针对侦察系统性能参数的不确定性,本文把灰色理论与层次分析法相结合,运用灰色层次分析综合评估模型,对侦察系统的效能进行评估。用专家评估分析法确定侦察装备效能评价指标权重,用灰色评估理论建立侦察系统效能评估模型。以某常规侦察雷达为例,用建立的模型进行量化评估,充分利用决策者的判断信息,较为准确地反映实际情况,验证了评估模型的可靠性。该模型可为部队作战提供装备的效能数据,为发展新型装备提供依据。其方法和成果可供其它武器系统效能评估时借鉴参考。     

Simultaneous determination of production and maintenance schedules using in‐line equipment condition and yield information

In many manufacturing environments, equipment condition has a significant impact on product quality, or yield. This paper presents a semi‐Markov decision process model of a single‐stage production system with multiple products and multiple maintenance actions. The model simultaneously determines maintenance and production schedules, accounting for the fact that equipment condition affects the yield of each product differently. It extends earlier work by allowing the expected time between decision epochs to vary by both action and machine state, by allowing multiple maintenance actions, and by treating the outcome of maintenance as less than certain. Sufficient conditions are developed that ensure the monotonicity of both the optimal production and maintenance actions. While the maintenance conditions closely resemble previously studied conditions for this type of problem, the production conditions represent a significant departure from earlier results. The simultaneous solution method is compared to an approach commonly used in industry, where the maintenance and production problems are treated independently. Solving more than one thousand test problems confirms that the combination of both features of the model—accounting for product differences and solving the problems simultaneously—has a significant impact on performance. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

Level product form QSF processes and an analysis of queues with Coxian interarrival distribution

In this article, we study a class of Quasi‐Skipfree (QSF) processes where the transition rate submatrices in the skipfree direction have a column times row structure. Under homogeneity and irreducibility assumptions we show that the stationary distributions of these processes have a product form as a function of the level. For an application, we will discuss the ‐queue that can be modeled as a QSF process on a two‐dimensional state space. In addition, we study the properties of the stationary distribution and derive monotonicity of the mean number of the customers in the queue, their mean sojourn time and the variance as a function of for fixed mean arrival rate. © 2016 Wiley Periodicals, Inc. Naval Research Logisticsxs 66:57–72, 2019