Inventory models with nonlinear shortage costs and stochastic lead times; applications of shape properties of randomly stopped counting processes

In this article, we study generalizations of some of the inventory models with nonlinear costs considered by Rosling in (Oper. Res. 50 (2002) 797–809). In particular, we extend the study of both the periodic review and the compound renewal demand processes from a constant lead time to a random lead time. We find that the quasiconvexity properties of the cost function (and therefore the existence of optimal (s, S) policies), holds true when the lead time has suitable log‐concavity properties. The results are derived by structural properties of renewal delayed processes stopped at an independent random time and by the study of log‐concavity properties of compound distributions. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 345–356, 2015     

气象水文软件测评系统建设研究

介绍了气象水文软件测评系统建设和研究情况,重点分析了测评系统的网络环境、硬件环境、软件环境、测试技术能力、测试流程管理等方面的建设和研究情况.     

可修系统可靠性统计分析模型的改进

阐述了复杂可修系统可靠性统计分析的特点及威布尔过程模型的适用性;引入修复影响系数对威布尔过程模型作了改进;给出了一个可供参考的计算示例.     

分段试验的可行性

运用随机点过程方法,从理论上对可修系统能否进行分段试验进行了研究.论证了对于泊松过程模型分段试验的可行性,并研究了分段试验对参数估计的影响.     

STK在电子战交战过程仿真中的应用

针对电子战交战过程仿真中作战效果难以评估、交战过程难以描述的问题,利用系统建模和视景仿真技术,探索了STK在电子战交战过程仿真中的应用方法,分析了STK的电子战仿真应用能力,建立了STK在电子进攻、电子防护和电子支援过程中应用的步骤,并以EA-18G为例,对其电子战交战过程进行了仿真和分析,为进行电子战交战过程数据化、工程化、可视化仿真提供了参考.     

反导作战中多TBM威胁评估模型研究

威胁评估模型是反导指挥控制系统中的关键模型之一.在分析和研究反导作战指挥控制问题的基础上,重点对TBM威胁评估的影响因素进行了分析总结;对各级反导指挥控制系统的威胁评估模型中的异同点进行了对比分析.最后结合层次分析法的相关理论给出了战区级反导指控系统威胁评估模型的求解过程.该算法在指控系统仿真应用中取得了较好的效果.对后续反导作战指挥控制问题的研究具有很高的参考价值.     

Technical note: A computationally efficient algorithm for undiscounted Markov decision processes with restricted observations

We present a computationally efficient procedure to determine control policies for an infinite horizon Markov Decision process with restricted observations. The optimal policy for the system with restricted observations is a function of the observation process and not the unobservable states of the system. Thus, the policy is stationary with respect to the partitioned state space. The algorithm we propose addresses the undiscounted average cost case. The algorithm combines a local search with a modified version of Howard's (Dynamic programming and Markov processes, MIT Press, Cambridge, MA, 1960) policy iteration method. We demonstrate empirically that the algorithm finds the optimal deterministic policy for over 96% of the problem instances generated. For large scale problem instances, we demonstrate that the average cost associated with the local optimal policy is lower than the average cost associated with an integer rounded policy produced by the algorithm of Serin and Kulkarni Math Methods Oper Res 61 (2005) 311–328. © 2008 Wiley Periodicals, Inc. Naval Research Logistics 2009     

Quality control chart design under Jidoka

We consider design of control charts in the presence of machine stoppages that are exogenously imposed (as under jidoka practices). Each stoppage creates an opportunity for inspection/repair at reduced cost. We first model a single machine facing opportunities arriving according to a Poisson process, develop the expressions for its operating characteristics and construct the optimization problem for economic design of a control chart. We, then, consider the multiple machine setting where individual machine stoppages may create inspection/repair opportunities for other machines. We develop exact expressions for the cases when all machines are either opportunity‐takers or not. On the basis of an approximation for the all‐taker case, we then propose an approximate model for the mixed case. In a numerical study, we examine the opportunity taking behavior of machines in both single and multiple machine settings and the impact of such practices on the design of an X – Q C chart. Our findings indicate that incorporating inspection/repair opportunities into QC chart design may provide considerable cost savings. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009     

基于Petri网的雷达对抗仿真建模研究

针对雷达对抗的作战过程,引入Petri网的数学方法描述雷达对杭侦察、雷达干扰、雷达干扰效能评佑3个作战行动,将雷达对抗战术规则与Petri网的实施规则相关联,并选用有效策略解决冲突变迁,建立雷达对抗的Petri网模型,解决了雷达对抗仿真建模过程中对并行、异步和随机时间等复杂离散事件的描述问题.     

幼儿教师流失：组织社会学视角

幼儿教师流失从宏观上讲是一项较为复杂的系统工程。组织社会学以一种动态的、全景式的、社会性的视野为分析幼儿教师流失提供了全新的视角和理念：幼儿教师个体与组织间的不协调性是造成其流失的实质;从过程上看,幼儿教师流失经历了萌芽阶段——幼儿教师流失意识的初步选择,谈判阶段——幼儿教师流失意向的基本成型和执行阶段——幼儿教师流失的形成三个阶段。最后就幼儿教师流失问题进行了反思提出了建议。