A two‐echelon inventory‐location problem with service considerations

We study the problem of designing a two‐echelon spare parts inventory system consisting of a central plant and a number of service centers each serving a set of customers with stochastic demand. Processing and storage capacities at both levels of facilities are limited. The manufacturing process is modeled as a queuing system at the plant. The goal is to optimize the base‐stock levels at both echelons, the location of service centers, and the allocation of customers to centers simultaneously, subject to service constraints. A mixed integer nonlinear programming model (MINLP) is formulated to minimize the total expected cost of the system. The problem is NP‐hard and a Lagrangian heuristic is proposed. We present computational results and discuss the trade‐off between cost and service. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009     

Approximation algorithms for general one‐warehouse multi‐retailer systems

Logistical planning problems are complicated in practice because planners have to deal with the challenges of demand planning and supply replenishment, while taking into account the issues of (i) inventory perishability and storage charges, (ii) management of backlog and/or lost sales, and (iii) cost saving opportunities due to economies of scale in order replenishment and transportation. It is therefore not surprising that many logistical planning problems are computationally difficult, and finding a good solution to these problems necessitates the development of many ad hoc algorithmic procedures to address various features of the planning problems. In this article, we identify simple conditions and structural properties associated with these logistical planning problems in which the warehouse is managed as a cross‐docking facility. Despite the nonlinear cost structures in the problems, we show that a solution that is within ε‐optimality can be obtained by solving a related piece‐wise linear concave cost multi‐commodity network flow problem. An immediate consequence of this result is that certain classes of logistical planning problems can be approximated by a factor of (1 + ε) in polynomial time. This significantly improves upon the results found in literature for these classes of problems. We also show that the piece‐wise linear concave cost network flow problem can be approximated to within a logarithmic factor via a large scale linear programming relaxation. We use polymatroidal constraints to capture the piece‐wise concavity feature of the cost functions. This gives rise to a unified and generic LP‐based approach for a large class of complicated logistical planning problems. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009     

复杂环境下线天线隔离度分析

讨论了一种复杂环境下线天线隔离度分析方法,此方法可以广泛运用于飞机、战车、导弹、舰船等复杂环境.采用一种矩量法(MOM)和一致几何绕射理论(UTD)的混合法,并结合二端口网络下天线间隔离度的知识来计算复杂环境下线天线隔离度.此混合法克服了单纯的矩量法难以计算电大尺寸系统中的天线,以及一致几何绕射理论的计算精度不够的缺点,最终能实现计算速度和计算精度的统一.     

一种基于球坐标的角速率耦合跟踪方法

针对机动目标跟踪中所获取的速度量测信息，分析了速度量测与位置量测信息的关系，建立了球坐标系下角速率耦合跟踪模型。将Coriolis加速度信息引入到对径向距离的滤波处理中，同时也探讨了角速度对径向距离滤波的影响。仿真结果表明，相比于其他几种方法，角速率耦合跟踪方法在一定程度上提高了跟踪精度。     

国防科技发展战略研究中的定性定量分新方法及应用研究

谋划和制定国防科技发展战略是综合运用多层次、多学科和多种类科学方法的过程。在国防科技发展战略的方法学基本框架下，对当前几种发展战略研究的定性定量方法进行综述，针对这些研究方法发挥作用的层次不同，结合国防科技发展战略研究案例，提出定性定量方法的综合运用框架，为进一步提高发展战略的科学性提供参考。     

略论克尼格累茨战役的军事、政治意义

19世纪60年代，普鲁士宰相俾斯麦推行强硬的“铁血政策”，为德意志统一展现了宏伟前景。普鲁士在国家军事力量的支撑下，综合运用外交、政治、战略手段，完成了梦寐以求的德意志统一大业。这其中普鲁士与奥地利对决的克尼格累茨战役起着关键性的作用。它不仅改变了欧洲政治和军事地图，打破了中欧地区的势力均衡，使普、奥两国命运发生不可逆转之变化，而且为德意志的完整、独立奠定了坚实基础，并推动了德意志走向穷兵黩武的军事帝国。     

培育当代革命军人核心价值观的关键着力点

增强培育当代革命军人核心价值观的主动性、针对性和有效性,必须注重在促进普遍理解认同和自觉培养践行上下功夫.促进理解认同的关键着力点是在对内涵和要求的深刻理解中把握当代革命军人核心价值观的根本指向.促进培养践行的关键着力点是在具体的思想和行为引导中促进当代革命军人核心价值观培育工作的深化.     

党员干部要胸怀忠诚心存敬畏行为坚守

党员干部要胸怀忠诚,最重要的是听党话、跟党走、永不叛党,最根本的是竭诚为党和人民努力工作,最难得的是甘愿为党和人民的事业牺牲奉献;党员干部要心存敬畏,要敬畏法纪,要敬畏人民,要敬畏责任;党员干部要行有坚守,坚守的根本是坚守信仰的崇高,坚守的核心是坚守人间的真情,坚守的关键是坚守人格的底线.     

努力加强信息国防建设

信息国防是现代国防的基础。要理顺信息国防体制,完善信息国防动员体系,发展信息国防关键技术,健全信息国防法律体系,建立信息国防武装力量。当前尤其要增强全民国防意识,建立和完善国家信息安全保障体系,加强国防信息力量建设。