A partial characterization of the optimal ordering/rationing policy for a periodic review system with two demand classes and backordering

We consider a finite horizon periodic review, single product inventory system with a fixed setup cost and two stochastic demand classes that differ in their backordering costs. In each period, one must decide whether and how much to order, and how much demand of the lower class should be satisfied. We show that the optimal ordering policy can be characterized as a state dependent (s,S) policy, and the rationing structure is partially obtained based on the subconvexity of the cost function. We then propose a simple heuristic rationing policy, which is easy to implement and close to optimal for intensive numerical examples. We further study the case when the first demand class is deterministic and must be satisfied immediately. We show the optimality of the state dependent (s,S) ordering policy, and obtain additional rationing structural properties. Based on these properties, the optimal ordering and rationing policy for any state can be generated by finding the optimal policy of only a finite set of states, and for each state in this set, the optimal policy is obtained simply by choosing a policy from at most two alternatives. An efficient algorithm is then proposed. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

试析新中国成立初期人民解放军学习苏军活动

新中国成立初期，人民解放军展开了学苏军活动。这次学苏军活动，经历了全面学习、有分析有批判地学习以及确立“以我为主”方针等三个历史阶段。通过学习、借鉴苏军经验，人民解放军技战术水平和协同作战能力有了很大提高，正规化现代化革命化建设取得显著成绩，同时也积累了许多值得借鉴的经验教训。     

军政现象与军政关系探微——兼论军事政治学的研究对象与核心问题

军事政治学是运用政治学的理论和方法研究军政现象，以探求军政关系发展规律为目标的一门军事学与政治学之间的交叉学科。当代世界存在的三大军政关系实践形态及其理论依据各具特色。正确评价军政关系必须确立和遵循客观的评价原则和方法，不断总结和运用马克思主义军事政治学理论，积极构建和发展中国特色的军事政治学，并充分发挥其学术功能和作用。     

预冷却引射系统性能一维分析

根据引射器的一维设计理论可知,二次流在进入混合室之前进行预冷降温可以提高引射效率,增大引射系数,但引入预冷器会同时引起流动损失,故需要对引射系统进行性能评估。针对设有预冷器的引射系统,应用一维理论分析预冷对系统性能的影响,重点分析预冷增强效果与流阻减弱效果对引射效率的作用。研究发现:预冷器对引射系统同时带来冷却增强作用和流阻减弱作用,横截面积和换热面积是主要影响因素。预冷器存在临界横截面积,横截面积大于临界值时,换热面积越大,引射性能越高;反之,换热面积越大,引射性能越低。等压混合引射方案比等截面混合引射方案性能高,前者引射系数比后者大60%;预冷却能够有效提高引射性能,尤其是等截面混合引射方案,性能提高可达35.5%。     

解读《2017美国海军陆战队航空建设计划》

海军陆战队是美军在海外执行任务的主要作战力量,其发展建设的重点将决定未来美军的海外战略重心。本文以《2017年美国海军陆战队航空兵建设计划》的主要内容为研究对象,概述了未来美国海军陆战队作战的总体构想,对美国海军陆战队主要更新换代的海空装备进行了研究分析,总结了美军海军陆战队航空建设的启示。以分析结果为依据,对未来美军的战略重心进行了判断。     

Multi-objectives nonlinear structure optimization for actuator in trajectory correction fuze subject to high impact loadings

This paper presents an actuator used for the trajectory correction fuze, which is subject to high impact loadings during launch. A simulation method is carried out to obtain the peak-peak stress value of each component, from which the ball bearings are possible failures according to the results. Subsequently, three schemes against impact loadings, full-element deep groove ball bearing and integrated raceway, needle roller thrust bearing assembly, and gaskets are utilized for redesigning the actuator to effectively reduce the bearings' stress. However, multi-objectives optimization still needs to be conducted for the gaskets to decrease the stress value further to the yield stress. Four gasket's structure parameters and three bearings' peak-peak stress are served as the four optimization variables and three objectives, respectively. Optimized Latin hypercube design is used for generating sample points, and Kriging model selected according to estimation result can establish the relationship between the variables and objec-tives, representing the simulation which is time-consuming. Accordingly, two optimization algorithms work out the Pareto solutions, from which the best solutions are selected, and verified by the simulation to determine the gaskets optimized structure parameters. It can be concluded that the simulation and optimization method based on these components is effective and efficient.     

信息化条件下联合作战战场优势转化

信息化条件下联合作战战场优势转化具有信息依赖性、对抗强烈性、效果综合性等特征.组织战场优势转化,必须遵循信息优势、决策优势、行动优势递进转化的规律,搞好总体设计、综合运用各种转化手段,并加强控制和协调,以提高战场优势转化的效率.     

用Maple设计回归分析实验课件

本文介绍在 Ｍａｐｌｅ上以测弹性模量为例制作的回归分析实验课件,课件具有可观性、交互性、文本交流等特性,并拥有 Ｍａｐｌｅ的资源,便于学习使用,可以用于解决实验数据处理的回归问题。     

电液伺服系统的建模与仿真研究

研究了电液伺服系统的理论建模,引入了一个非线性状态空间模型来描述电液伺服系统的动态特性．并且应用了Matlab提供的模拟仿真工具Simulink实现了模拟仿真．通过仿真结果与实际系统的响应相比较,验证了理论模型描述实际电液伺服系统动态特性的准确性,为今后设计高质量的控制器打下了良好的基础．     

微弱信号测量的一种实现方法

介绍了一种μＶ级微弱电信号测量的实现方法,给出了测量放大电路的具体设计以及信号采集与处理软件流程图．与传统测量方法相比,此测量方法所使用的仪器体积小,重构测量系统方便,可直接由计算机对信号进行分析,是目前信号测量的主要发展方向．