鲁棒稳定控制器的参数化设计方法

基于特征结构配置参数化方法,讨论了一类匹配的不确定线性系统的鲁棒控制问题,目的是设计鲁棒稳定控制器,使不确定闭环线性系统的特征值始终位于复平面的左半平面中某扇形区域内.给出了该鲁棒稳定控制器存在的充分条件及其参数化表示,可进一步利用其自由度满足某些设计要求.给出的数值例子,表明了鲁棒稳定控制器参数化设计方法的有效性.     

A combination of Lagrangian relaxation and column generation for order batching in steelmaking and continuous‐casting production

This article considers the order batching problem in steelmaking and continuous‐casting production. The problem is to jointly specify the slabs needed to satisfy each customer order and group all the slabs of different customer orders into production batches. A novel mixed integer programming model is formulated for the problem. Through relaxing the order assignment constraints, a Lagrangian relaxation model is then obtained. By exploiting the relationship between Lagrangian relaxation and column generation, we develop a combined algorithm that contains nested double loops. At the inner loop, the subgradient method is applied for approximating the Lagrangian dual problem and pricing out columns of the master problem corresponding to the linear dual form of the Lagrangian dual problem. At the outer loop, column generation is employed to solve the master problem exactly and adjust Lagrangian multipliers. Computational experiments are carried out using real data collected from a large steel company, as well as on large‐scaled problem instances randomly generated. The results demonstrate that the combined algorithm can obtain tighter lower bound and higher quality solution within an acceptable computation time as compared to the conventional Lagrangian relaxation algorithm. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

多品种备件联合申请的聚集效应

根据联合申请的备件品种范围的不同,提出了3种订货策略,即单独申请、统一申请和联合申请,并设计了联合申请策略的启发式算法。该算法首先确定订购最频繁的备件,将其申请周期作为基本申请周期,其他备件申请周期是该周期的整倍数;其次寻求各种备件的最优订货倍数;最后确定各种备件的订购量。数值实例表明：联合申请策略的聚集效应明显优于单独申请策略和统一申请策略,对多品种库存控制策略的研究有一定意义。     

装备保障能力评价参数体系设计与应用

为了及时发现装备作战单元在装备保障建设中存在的问题并确定原因,研究了装备保障能力评价参数体系的构建。在剖析装备保障能力概念的基础上,将能力评价参数分为综合层、系统层、子系统层及资源层。从参数内容、评价对象层次以及时域3个维度设计了评价参数体系框架,并据此对4个层次参数的选取及其关系分别进行了探讨。最后通过某防空旅装备保障能力评价实例,验证了参数体系设计方法的可操作性和有效性。     

用伴随方程研究烟幕施放的优化问题

从描述烟幕扩散的基本方程出发,提出了一类烟幕施放的优化问题．文中指出,这类问题由于约束条件为复杂的偏微分方程,计算量很大,难以直接求解．为了解决这一问题,引入了一种伴随方法以降低计算量．推导了三维非平坦地形下大气平流一扩散方程的伴随方程,利用伴随方程和原方程的关系,对优化问题进行了等价变形,大大降低了计算量．最后通过一个算例,对这一方法的有效性进行了演示。     

美军军事转型及其启示(下)

三、美国军事转型的主要特性(一)顶层设计,追求“跨越一代”的规划效果美国军事转型的最显著特点就是谋求跨越时代的超前性,这种谋求超前性的强烈欲望,一方面来自美国人强烈的时代感和机遇意识,另一方面来自他们居安思危的忧患意识。信息技术群的迅猛发展,深刻改变着社会生活的     

试论抗大办学治校的成功经验

抗大在历时9年的办学历程中,坚决贯彻执行“坚定正确的政治方向,艰苦朴素的工作作风,灵活机动的战略战术”的教育方针和“团结、紧张、严肃、活泼”的校训,为八路军、新四军等人民抗日武装培养输送了10多万名军政人才,为夺取抗日民族解放战争的伟大胜利作出了重要贡献,为人民军队院校建设积累了宝贵经验。     

德国顾问团参与中国抗战活动之剖析

在20世纪30年代,受聘于国民政府的德国顾问团参与了中国人民抗击日本法西斯侵略的伟大斗争,为中国反法西斯斗争的胜利作出了重要贡献。他们的到来既是以蒋介石为首的国民党维护其统治的需要,也是德国垄断巨头为实现其战略利益而在中国“押的宝”。     

Vertically restrictive pricing in supply chains with price‐dependent demand

We examine the behavior of a manufacturer and a retailer in a decentralized supply chain under price‐dependent, stochastic demand. We model a retail fixed markup (RFM) policy, which can arise as a form of vertically restrictive pricing in a supply chain, and we examine its effect on supply chain performance. We prove the existence of the optimal pricing and replenishment policies when demand has a linear additive form and the distribution of the uncertainty component has a nondecreasing failure rate. We numerically compare the relative performance of RFM to a price‐only contract and we find that RFM results in greater profit for the supply chain than the price‐only contract in a variety of scenarios. We find that RFM can lead to Pareto‐improving solutions where both the supplier and the retailer earn more profit than under a price‐only contract. Finally, we compare RFM to a buyback contract and explore the implications of allowing the fixed markup parameter to be endogenous to the model. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006.     

Quay crane scheduling at container terminals to minimize the maximum relative tardiness of vessel departures

In this paper, we study the problem of scheduling quay cranes (QCs) at container terminals where incoming vessels have different ready times. The objective is to minimize the maximum relative tardiness of vessel departures. The problem can be formulated as a mixed integer linear programming (MILP) model of large size that is difficult to solve directly. We propose a heuristic decomposition approach to breakdown the problem into two smaller, linked models, the vessel‐level and the berth‐level models. With the same berth‐level model, two heuristic methods are developed using different vessel‐level models. Computational experiments show that the proposed approach is effective and efficient. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2006