On the (S − 1, S) lost sales inventory model with priority demand classes

In this paper an inventory model with several demand classes, prioritised according to importance, is analysed. We consider a lot‐for‐lot or (S ? 1, S) inventory model with lost sales. For each demand class there is a critical stock level at and below which demand from that class is not satisfied from stock on hand. In this way stock is retained to meet demand from higher priority demand classes. A set of such critical levels determines the stocking policy. For Poisson demand and a generally distributed lead time, we derive expressions for the service levels for each demand class and the average total cost per unit time. Efficient solution methods for obtaining optimal policies, with and without service level constraints, are presented. Numerical experiments in which the solution methods are tested demonstrate that significant cost reductions can be achieved by distinguishing between demand classes. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 593–610, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10032     

Inventory pooling games for expensive,low‐demand spare parts

We consider several independent decision makers who stock expensive, low‐demand spare parts for their high‐tech machines. They can collaborate by full pooling of their inventories via free transshipments. We examine the stability of such pooling arrangements, and we address the issue of fairly distributing the collective holding and downtime costs over the participants, by applying concepts from cooperative game theory. We consider two settings: one where each party maintains a predetermined stocking level and one where base stock levels are optimized. For the setting with fixed stocking levels, we unravel the possibly conflicting effects of implementing a full pooling arrangement and study these effects separately to establish intuitive conditions for existence of a stable cost allocation. For the setting with optimized stocking levels, we provide a simple proportional rule that accomplishes a population monotonic allocation scheme if downtime costs are symmetric among participants. Although our whole analysis is motivated by spare parts applications, all results are also applicable to other pooled resource systems of which the steady‐state behavior is equivalent to that of an Erlang loss system. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

防区外联合攻击武器火控系统分析与研究

从一般的空面精确制导武器系统到远射程的防区外联合攻击武器系统,技术更新和发展很多.针对防区外联合攻击武器系统的特点,对防区外联合攻击武器火控系统的总体技术进行了研究探讨,对其武器火控系统的组成、功能、攻击发射方式、工作流程等进行了分析,给出了防区外联合攻击武器火控系统精度分析与分配的方法,并进行了仿真计算和分析,验证了精度分析的有效性.     

一种改进的变步长归一化LMS算法

在以往的基于ＬＭＳ算法的研究中，归一化ＬＭＳ算法（ＮＬＭＳ）增大了算法的动态输入范围，但该算法对噪声很敏感。引入自相关的变步长ＬＭＳ算法（ＶＳＳＬＭＳ）不仅加快了收敛速度，可在非平稳状态下进行快速跟踪，而且消除了独立噪声的干扰，但它无法适应大范围的动态输入。本文综合它们的优点而得到的算法，在低信噪比和大范围的动态输入情况下都有良好的性能。     

相控阵天线阵面两级备件优化配置模型

针对相控阵天线阵面备件配置存在的冗余性强、批量送修、多级维修等现实问题,综合考虑备件费用、维修能力以及库存策略之间的关系,建立了基于定期补给的两级备件优化配置模型。给出了系统的故障件维修周转过程和维修备件的定期补给过程,在分析备件、库存、维修能力之间关系的基础上,结合成批到达的排队理论,建立了系统的供应可用度模型。以备件配置费用最小为目标、以系统供应可用度为约束条件,建立了系统的备件优化配置模型,并通过边际效益分析法对模型进行了求解。通过算例仿真与分析对模型进行了验证。结果表明:构建的备件配置能够较好地解决相控阵天线阵面的备件配置问题,具有一定的优越性。     

引信传爆管旋卸头设计

引信传爆管的旋卸是勤务处理中的一个重要问题。旋卸时,传爆管无法卸下和传爆管受损的情况时有发生。针对这一问题和引信自动分解的要求,将传爆管分为槽型、孔型、锁紧螺母和光滑圆柱面型等三种类型,相应地设计了刀片型、卡针型和卡爪型三种旋卸头,重点研究了卡爪型及其卡爪曲线设计计算方法。试验表明三种旋卸头均工作可靠。     

确定舰艇备件携带量的贝叶斯方法

本文针对一些舰艇的小子样特点,推出了确定其备件携带量的贝叶斯方法。     

HLA仿真中利用Stage实现控制和演示方法

高层体系结构HLA(HighLevelArchitecture)是美国国防部为保证各种仿真应用之间的互操作性而建立的一个通用仿真技术框架核心,现已作为IEEE1516标准广泛应用于各种分布式仿真。在实现基于HLA的C4ISR体系结构仿真中,提出了一种利用Stage控制和演示仿真过程的方法,并解决了其中RTI时钟和Stage时钟的不同步问题,有效地完成了仿真过程的直观演示和控制。     

坦克稳定器的自抗扰控制算法

为解决坦克稳定器中存在的传动间隙、干摩擦等强非线性问题,提高系统的鲁棒性,基于自抗扰控制器(ADRC)原理,提出了适用于坦克稳定器的自抗扰控制器,并进行了计算机仿真和试验验证。证明了自抗扰控制算法在坦克稳定器设计中的可行性。     

备品备件需求确定方法探讨

分析了备品备件需求确定的重要性,探讨了结合现有的国家军用标准进行备品备件需求确定的程序与方法,对现有方法存在的问题进行了分析并提出了建议.