Optimal production and maintenance policy for imperfect production systems

A joint optimization of the production run length and preventive maintenance (PM) policy is studied for a deteriorating production system where the in‐control period follows a general probability distribution with non‐decreasing failure rate. In the literature, the sufficient conditions for the optimality of the equal‐interval PM schedule is explored to derive an optimal production run length and an optimal number of PM actions. Nevertheless, an exhaustive search may arise. In this study, based on the assumption that the conditions for the optimality of the equal‐interval PM schedule hold, we derive some structural properties for the optimal production/PM policy, which increases the efficiency of the solution procedure. These analyses have implications for the practical application of the production/PM model to be more available in practice. A numerical example of gamma shift distribution with non‐decreasing failure rates is used to illustrate the solution procedure, leading to some insight into the management process. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2006     

多量子阱红外焦平面阵列研制进展

研制红外凝视成像导引头的一项关键技术,是要制造大面积的性能均匀的红外焦平面阵列。近年来,从能带工程的观点出发,使用以现代薄膜技术制造的多量子阱超晶格材料,采用微电子技术研制的多量子阱红外焦平面阵列的工作进展很快,备受人们关注。了解有关的发展背景、基本原理、先进技术和研制实例是十分有益的。     

论近代中美军事战略关系的形成

本文从中美经济政治关系的产生、发展及蜕变与两国军事关系的萌芽,美国门户开放政策的军事含义及其对中美军事关系的深远影响,日本在远东及太平洋的侵略扩张与中美军事战略关系正式形成等三个方面,对中美军事战略关系在特定阶段的表现形式及特点进行了分析探讨。     

隐身涂料的研究及发展现状

综述了隐身涂料的分类、研究及发展现状,包括可见光隐身涂料,红外隐身涂料,激光隐身涂料、雷迭隐身涂料,声呐隐身涂料和多功能隐身涂料等。     

Machine scheduling with an availability constraint and job delivery coordination

In this paper we study the scheduling problem that considers both production and job delivery at the same time with machine availability considerations. Only one vehicle is available to deliver jobs in a fixed transportation time to a distribution center. The vehicle can load at most K jobs as a delivery batch in one shipment due to the vehicle capacity constraint. The objective is to minimize the arrival time of the last delivery batch to the distribution center. Since machines may not always be available over the production period in real life due to preventive maintenance, we incorporate machine availability into the models. Three scenarios of the problem are studied. For the problem in which the jobs are processed on a single machine and the jobs interrupted by the unavailable machine interval are resumable, we provide a polynomial algorithm to solve the problem optimally. For the problem in which the jobs are processed on a single machine and the interrupted jobs are nonresumable, we first show that the problem is NP‐hard. We then propose a heuristic with a worst‐case error bound of 1/2 and show that the bound is tight. For the problem in which the jobs are processed on either one of two parallel machines, where only one machine has an unavailable interval and the interrupted jobs are resumable, we propose a heuristic with a worst‐case error bound of 2/3. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

后方司令部并非实体组织

1937年春成立的中革军委后方司令部(简称后方司令部),是一个实体组织还仅是一种名义?长期以来存在着不同见解.一种意见是:其成立及机构设置有一些原始记载,因此是实体;另一种意见是:后方司令部仅是一种名义,不是实体,实体仍是军委总司令部.     

解放全国大陆的最后一次战役——昌都战役

1950年春,继2月陈赓司令员率第4兵团部进驻昆明、3月第4兵团和第18兵团各一部胜利举行西昌战役(4月又解放海南岛)后,川、黔、滇、康四省均告解放,全国大陆唯一尚待解放的省区就是西藏了.     

史迪威与杜聿明在缅甸战场上的恩怨纠葛(下)

五、同举平满纳会战,史迪威与杜聿明两人重归于好 史迪威对于我想给他讲述《将相和》故事的用心,虽然已表示理解,并嘱我放心他同杜聿明的关系,但在3月31日他到重庆向蒋介石汇报时,仍然告了杜聿明的"状",指责杜聿明和廖耀湘蔑视他的权威,不听他的命令,遂使同古攻势夭折,缅甸战局逆转,请求处分杜、廖二人.同时他还向蒋介石说他要辞职回国,不回缅甸了.     

边疆高校本科生导师制的实施研究

本科生导师制是师生双向选择的前提下,由品德兼优的教学、科研的骨干教师,担任本科生的指导教师,对学生的学习、生活、品德及心理等进行个别具体指导的教学制度。边疆高校办学条件差,基础薄弱,生源质量及学生自主学习能力差等,导师制的实施正是抓住了这个薄弱环节和不利因素,着力于学生综合素质的提高,是促进教学质量提高的一条有效的途径。     

清火器营初考

清朝八旗满洲、八旗汉军与绿营火器营的创制,历朝《会典》、《会典事例》的记载含混。本文考证了火器营的创始时间与背景;梳理了入关前"八旗火器营"即"八旗炮手兵"到"旧汉兵"、"汉军火器营"再到"八旗满洲火器营"各军兵种的制度演进路径;探讨了清军军制变革与八旗制的形成、清朝的国家政治建设互动关系,揭示了清军军制变革的路径依赖,强调了制度变革继承性。