Purchase and retrieval competition for seasonal produce

We study the competition problem of purchase and multiretrieval of perishable seasonal produce, where wholesalers purchase and stock their products in the first period, and then retrieve and sell them in subsequent periods. We first consider the duopoly case and assume that the prices are exogenous and fluctuate. In each period, after the price realization, the wholesalers retrieve some stock from their warehouses to satisfy their demands. One wholesaler's unsatisfied customers can switch to another and be satisfied by its left retrieved products. Any unsold retrieved stock has no salvage value and any unsatisfied demand is lost. The unretrieved stock is carried to the next period at a perishable rate. The wholesalers compete for the substitute demand by determining their own purchase and retrieval quantities. We show the existence and uniqueness of a pure-strategy Nash equilibrium, and that the Nash equilibrium strategy has the simple “sell-down-to” structure. We also consider the general N-person game and show the existence of the Nash equilibrium, and characterize the structure of the equilibrium strategy for the symmetric case. In addition, we consider the case with endogenous prices, and show that the problem reduces to a repeated newsvendor game with price and inventory competition. We derive the conditions under which a unique Nash equilibrium exists and characterize the equilibrium strategy. Finally, we conduct numerical studies to examine the impacts of the model parameters on the equilibrium outcomes and to generate managerial insights.     

Evaluation of base-stock policies in multiechelon inventory systems with state-dependent demands part I: State-independent policies

This article analyzes a model of a multiechelon inventory system. The exogenous demands form Markov-modulated Poisson processes. That is, the demand rates are functions of an underlying Markov chain. Each location follows a base-stock policy which is independent of the state of the underlying Markov chain. We employ the exogenous transit mechanism introduced by Zipkin [7] and Svoronos and Zipkin [6]. The transit times between locations have phase-type distributions. An exact procedure to compute steady-state performance measures is presented. © 1992 John Wiley & Sons, Inc.     

复杂作战任务弹药配备模型

多阶段任务系统(PMS)是一种典型的复杂系统,它包括多个在时间上连续且无相互重叠的基本任务,武器系统的作战过程多数属于这种复杂系统.以某作战单元的一次作战任务流程为例,详细地讨论了多阶段复杂任务系统的特点,并从基本任务阶段的系统可信性、可用度的角度出发,分析了在满足给定火力指标的前提下,建立整个复杂作战任务流程中弹药配备模型的方法.     

传感器失效的飞控系统完整性控制器设计

从提高新一代战斗机可靠性和性能出发,提出对飞控系统传感器失效具有完整性的鲁棒容错控制器设计方法.采用状态观测器理论和H∞鲁棒控制理论相结合的方法,针对已知故障设计的控制器,在传感器正常和故障两种情况下,既保证闭环系统的鲁棒稳定性,又保证了闭环系统对于外界干扰具有要求的H∞范数指标.以某型战斗机为算例,考虑俯仰角速率传感器失效和阵风干扰,进行控制器设计,仿真结果验证该方法的正确性和有效性.     

科研经费管理决策支持系统若干模型

本文应用多目标决策原理和计算机技术,在分析用户需求的基础上,建立了科研任务项目的预测评价和经费分配模型,并分析了有关模型的关系和解决性质。根据这些模型和决策的特点,简要叙述了该系统的主要功能。我们相信。该系统的应用,将给管理人员提供方便,且使管理进一步科学化,让有限的经费发挥更大的作用。     

一个具有相互独立、不同分布服务时间序列的排队模型

讨论的排队模型 ,放宽了GI/G/1系统中“服务时间独立同分布”的限制 ,只要求各服务时间相互独立 ,因而较GI/G/1排队模型能更合理地拟合实际问题 .在此较宽的条件下 ,利用补充变量的方法 ,求得了该排队系统队长的瞬时分布     

试论胡锦涛关于国防和军队建设的三大战略思想及其发展脉络

本文论述了胡锦涛国防和军队建设的三大战略思想：融入党和国家顶层战略的富国强军思想,全面维护国家利益、强调能力导向的军队新使命思想以及国家多元安全能力一体化建设与运用的全民国防思想,并对这些思想提出的特殊实践背景和来龙去脉,及其所要解决的特殊实践问题进行了剖析。     

李凤苞、徐建寅主持购买铁甲舰考论

1879年后,晚清海防形势日益严峻,清政府撇开赫德,委派李凤苞、徐建寅主持购买铁甲舰;李凤苞、徐建寅主持购买铁甲舰的曲折过程及其中复杂的人事关系折射出晚清海军建设的艰辛。     

我军思想政治建设史上的重要创新工程

当代革命军人核心价值观是我军优良传统和时代精神的高度凝练,是军人安身立命之本、为人处世之基,是有效履行新世纪新阶段我军历史使命的强大精神动力.培育当代革命军人核心价值观,是我军思想政治建设的重要创新工程,必须从战略高度坚持不懈地抓紧抓实抓出成效,使之真正成为我军的内在精神和生命之魂.     

着力推进非战争军事行动政治工作

非战争军事行动,作为军事斗争发展到一定阶段的历史现象,是新形势下关于国家安全问题的一个重大命题.要廓清思想认识,进一步认清抓好非战争军事行动政治工作的重大现实意义;扭住关键环节,进一步理清组织开展非战争军事行动政治工作的思路重点;创新方法模式,进一步增强非战争军事行动政治工作的实际效果;加强组织领导,进一步推进非战争军事行动政治工作的深入发展.