基于系统贴近度的装备中修费用估算模型

装备维修费用是装备中修过程最直接、最敏感的决策因素,为科学合理地估算修理机构装备中修费用,通过对装备中修范围和中修费用结构的分析,运用模糊数学中的隶属度和贴近度相关理论以及平滑指数法建模思路,构建了基于系统贴近度的装备中修费用估算模型,并通过对某新入役装备进行估算分析,验证了该模型的科学性和结果的可靠性.     

基于IDEF3的部队装备中修业务流程优化重组

以IDEF3为工具描述了部队装备中修业务流程,分析了流程中存在的问题,通过采用基于状态的维修方式、无损检测先进技术手段、共享维修保障信息和调整器材发放审批权限等方法,对部队现行装备中修业务流程进行了优化,可有效解决装备维修过剩、维修不足、维修资源浪费和维修周期过长等问题．     

总师谈某型潜艇首次自主中修及改换装工程

在解放军海军六十多年的发展历程中,相继从苏联、欧美、俄罗斯引进装备和技术,但学习、引进的目的是为了最终的"不引进"。千里之行始于足下,筚路褴褛、披荆斩棘的艰辛虽不足以为外人道,但成果总是令人欢欣鼓舞。今年的"国家科技进步二等奖"项目中就有某型潜艇的中修及改换装。中修是最高等级的计划修理,而改换装等于是赋予了潜艇新一轮生命。《现代舰船》对主持该项目的总师、技术少将朱石坚进行了采访,请他介绍该项目的创新之处,并解答潜艇中修的相关理论和实践问题。     

基于CCA/DEA的装备维修保障绩效评价

运用典型相关分析方法(CCA)和数据包络法(DEA),从纯技术效率、规模效率和综合效率3方面对空军飞行团维修保障绩效进行计算分析,结果表明,飞行团维修费使用效益方面经费配置效率整体不高,特别是对于中修费和维修器材购置费,须采取管控措施提高经费利用效率。     

舰用锅炉管子根部烟灰腐蚀与刷镀层防护的应用研究

本文针对舰用主锅炉管子根部存在早期烟灰腐蚀问题,就应用刷镀技术将管子根部施镀防护层进行了多方面研究。为了能在实舰锅炉上试验与应用,我们通过一系列的实验室试验,对其镀层进行优化、检验,并结合某舰进厂中修对其主锅炉最容易产生腐蚀穿孔失效的部分管子实施刷镀,安装后使用近一年的情况表明：效果良好。     

评北约对南联盟空袭行动

从1999年3月25日至4月6日,以美国为首的北约13国联军对南斯拉夫联盟先后进行了12轮代号为“联盟行动”的空中打击。而且仍将继续扩大空袭规模,亦可能动用地面部队。这次“联盟行动”是美国实施新军事战略的一次实践。     

低轮PUFFIN算法的积分攻击

PUFFIN是一个分组长度为64bit的轻量级分组密码算法,其密钥长度为128bit。对PUFFIN抵抗积分攻击的能力进行研究,构造并证明PUFFIN算法存在5轮和6轮积分区分器。利用6轮积分区分器对8轮PUFFIN进行积分攻击,可恢复2轮共100bit轮密钥,攻击的数据复杂度为220个选择明文,时间复杂度约为233次8轮加密,存储复杂度为220,这是目前为止对PUFFIN最好的积分分析结果。     

某型坦克炮控检测系统的实现

从检测技术出发,介绍了某型坦克炮控检测系统的设计和原理。该系统以智能化检测手段,分级别实现了对该型坦克炮控系统相应小修、中修的性能检测。     

中修舰艇提升全面建设水平应把握的重点

中修是舰艇生命力的中点,持续时间相对较长,是修舰育人、持续全方位大幅度提升部队建设水平的良好契机。充分利用这个转折点,瞄准战斗力标准,使部队各项秩序正规,建设水平稳中有升,履行强军使命更加有效,应该把握住几个重点。一、针对任务转换的特点,要加强党委筹划,明确目标思路舰艇进厂中修,从一类舰变成三类舰,承担的任务和在航时完全不同,人员情况发生很大变化,各项工作开展都呈现出新的特点。     

ARIA分组密码差分功耗分析

分析了密码算法加密过程的功耗泄露模型,给出了差分功耗分析的基本原理,针对ARIA分组密码中查找S盒的功耗泄漏进行了差分功耗分析,并进行仿真实验。实验结果表明：ARIA密码中S盒查表操作功耗消耗易遭受差分功耗攻击,对800个随机明文的功耗曲线进行实验分析,可获取ARIA加密前4轮轮密钥,结合密钥扩展算法即可获取128位的主密钥。     

船用主锅炉筒身管孔超差应用电刷镀修复的研究

本文通过实验室模拟试验以及实船试验,对船用主锅炉筒身管孔超差应用电刷镀技术修复的可行性进行了研究,所得结论是肯定的。试验中,作者进行了镀层结构的优化设计、工艺比较,并多次进行胀管、退管（检验镀层结合力）及耐温试验,为船试奠定了坚实的基础。１９９３年４月结合某船锅炉中修对３号炉过热器筒管孔进行了刷镀试验,修复质量经厂方检验合格。     

Queueing models for spares provisioning

A population of items which break down at random times and require repair is studied (the classic “machine repair problem with spares”). It is desired to determine the number of repair channels and spares required over a multiyear planning horizon in which population size and component reliability varies, and a service level constraint is imposed. When an item fails, a spare (if available) is immediately dispatched to replace the failed item. The failed item is removed, transported to the repair depot, repaired, and then placed in the spares pool (which is constrained to be empty not more than 10% of the time) unless there is a backlog of requests for spares, in which case it is dispatched immediately. The first model considered treats removal, transportation, and repair as one service operation. The second model is a series queue which allows for the separate treatment of removal, transportation, and repair. Breakdowns are assumed Poisson and repair times exponential.     

Outsourcing warranty repairs: Dynamic allocation

In this paper we consider the problem of minimizing the costs of outsourcing warranty repairs when failed items are dynamically routed to one of several service vendors. In our model, the manufacturer incurs a repair cost each time an item needs repair and also incurs a goodwill cost while an item is awaiting and undergoing repair. For a large manufacturer with annual warranty costs in the tens of millions of dollars, even a small relative cost reduction from the use of dynamic (rather than static) allocation may be practically significant. However, due to the size of the state space, the resulting dynamic programming problem is not exactly solvable in practice. Furthermore, standard routing heuristics, such as join‐the‐shortest‐queue, are simply not good enough to identify potential cost savings of any significance. We use two different approaches to develop effective, simply structured index policies for the dynamic allocation problem. The first uses dynamic programming policy improvement while the second deploys Whittle's proposal for restless bandits. The closed form indices concerned are new and the policies sufficiently close to optimal to provide cost savings over static allocation. All results of this paper are demonstrated using a simulation study. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005     

A queuing model for due date control in a multiserver repair shop

This paper deals with a repair shop with multiple parallel servers, which has to carry out planned overhauls. Each overhaul consists of a large number of maintenance jobs. The overhaul process is interrupted by randomly arriving emergency jobs. To control the delivery performance of the overhauls, knowledge about the overhaul makespan distribution should be available. Using a 2‐dimensional Markov model, we derive the first and second moment of the overhaul makespan analytically for the case that the repair times of all overhaul jobs are identically and exponentially distributed. For the case of nonidentical repair time distributions, an approximation is presented. Simulation shows that the makespan distribution fitted on these moments gives an excellent approximation. © John Wiley & Sons, Inc. Naval Research Logistics 48: 281–282, 2001     

A deterministic inventory model for reparable items

A reparable inventory system has two distinct inventories within it—the inventory of items ready-for-issue and the inventory of carcasses available for repair. A reparable item is usually rebuilt upon failure, but the scrap rate in the repair process is generally positive. Consequently, new items must be procured from time to time to replace those item: which were scrapped. The ready-for-issue inventory has two input sources—procurement and repair, This paper develops a deterministic inbentory model for the reparable inventory system, and determines the optimal procurement and repair quantities.     

Country survey VI: Australia

Australia is a geographically large country, with the world's longest national coastline to defend, but a relatively small economy of some 17.5 million people. Since World War II, Australia has faced the dilemma of how to structure defence policy in the absence of an identifiable threat. Its policy of self‐reliance aims to permit Australia to conduct defensive operations in the event of low/medium level threats without depending immediately on its allies. This is to be achieved through the technological sophistication of defence equipment, a highly professional but small defence force and local industry support.

The burden of defence, measured as the share of defence outlay in GDP declined from about 3% in 1971–72 to about 2.3% in 1993–94. It has been the Government's policy to encourage the development of local defence‐related industry, in particular in areas such as: electronics/optics; communications and information technology; aerospace; shipbuilding and repair, munitions; and land vehicles. However, defence procurement has a small impact on the Australian economy as a whole.     

An optimum group maintenance policy

In this article we present an optimum maintenance policy for a group of machines subject to stochastic failures where the repair cost and production loss due to the breakdown of machines are minimized. A nomograph was developed for machines with exponential failure time distributions. The optimal schedule time for repair as well as the total repair cost per cycle can be obtained easily from the nomograph. Conditions for the existence of a unique solution for the optimum schedule and the bounds for the schedule are discussed.     

Optimal design of a multi-item,multi-location,multi-repair type repair and supply system

The design of a system with many locations, each with many items which may fail while in use, is considered. When items fail, they require repair; the particular type of repair being governed by a probability distribution. As repairs may be lengthy, spares are kept on hand to replace failed items. System ineffectiveness is measured by expected weighted shortages over all items and locations, in steady state. This can be reduced by either having more spares or shorter expected repair times. Design consists of a provisioning of the number of spares for each item, by location; and specifying the expected repair times for each type of repair, by item and location. The optimal design minimizes expected shortages within a budget constraint, which covers both (i) procurement of spares and (ii) procurement of equipment and manning levels for the repair facilities. All costs are assumed to be separable so that a Lagrangian approach is fruitful, yielding an implementable algorithm with outputs useful for sensitivity analysis. A numerical example is presented.     

Spares stocking policies for repairable items with dependent repair times

This paper analyzes the problem of determining desirable spares inventory levels for repairable items with dependent repair times. The problem is important for repairable products such as aircraft engines which can have very large investment in spares inventory levels. While existing models can be used to determine optimal inventory spares levels when repair times are independent, the practical considerations of limited repair shop capacity and prioritized shop dispatching rules combine to make repair times not independent of one another. In this research a simulation model of a limited capacity repair facility with prioritized scheduling is used to explore a variety of heuristic approaches to the spares stocking decision. The heuristics are also compared with use of a model requiring independent repair times (even though that assumption is not valid here). The results show that even when repair time dependencies are present, the performance of a model which assumes independent repair times is quite good.