Application of renewal theory to continuous sampling plans

Renewal theory is used to study the effectiveness of a class of continuous sampling plans first introduced by Dodge. This approach provides a simple way of viewing and computing the long-run Average Outgoing Quality (AOQ) and its maximum AOQL. More importantly, it is used to study the average outgoing quality in a short production run through an approximation formula AOQ^*(t). Formulas for AOQ and AOQ^*(t) are provided. By simulation, it is found that AOQ^*(t) is sufficiently accurate in situations corresponding to actual practice.     

Exponential size neighborhoods for makespan minimization scheduling

We investigate the quality of local search heuristics for the scheduling problem of minimizing the makespan on identical parallel machines. We study exponential size neighborhoods (whose size grows exponentially with the input length) that can be searched in polynomial time, and we derive worst‐case approximation guarantees for the local optima of such neighborhoods. The so‐called split neighborhood splits a feasible schedule into two layers, and then recombines the two layers by finding a perfect matching. We show that the makespan of every local optimum for split is at most a factor of 2 away from the globally optimal makespan. We then combine the split neighborhood with two neighborhoods from the literature. The combination of split with the jump neighborhood only marginally improves the approximation guarantee, whereas the combination with the lexicographic‐jump neighborhood decreases the approximation guarantee from 2 to 3/2. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

基于信息模型的C4ISR系统需求集成方法

多视图需求工程中"分而治之"的需求开发方式,必然会产生"需要集成"和"如何集成"等问题.研究了基于多视图的C<'4>ISR系统需求框架及其视图产品,并在此基础上给出了C<'4>ISR系统需求集成的概念与范围.通过建立需求信息模型,从语法、语义和语用三个层次研究构建一个需求集成框架.通过需求产品之间的关联关系,分析不同视图产品在集成中存在的问题,并给出了需求集成框架中不同需求产品的集成过程,为C<'4>ISR系统需求集成问题的解决提供一个可供参考的方法.     

左手材料涂敷目标的RCS仿真研究

左手材料的介电常数和磁导率都为负值,电场、磁场和波矢量在左手材料中表现为左手螺旋关系,相速与群速方向相反。根据传输线理论分析了波入射到分层媒质上的表面反射系数,计算了随入射波频率、涂层厚度变化情况下的左、右手材料的反射率;基于非均匀有理B样条参数曲面模拟目标的几何外形,采用物理光学法计算了涂敷左手材料目标的雷达散射截面...     

Capacity allocation to sales agents in a decentralized logistics network

Many logistics systems operate in a decentralized way, while most optimization models assume a centralized planner. One example of a decentralized system is in some sea cargo companies: sales agents, who share ship capacity on a network, independently accept cargo from their location and contribute to the revenue of the system. The central headquarters does not directly control the agents' decisions but can influence them through system design and incentives. In this paper, we model the firm's problem to determine the best capacity allocation to the agents such that system revenue is maximized. In the special case of a single‐route, we formulate the problem as a mixed integer program incorporating the optimal agent behavior. For the NP‐hard multiple‐route case, we propose several heuristics for the problem. Computational experiments show that the decentralized system generally performs worse when network capacity is tight and that the heuristics perform reasonably well. We show that the decentralized system may perform arbitrarily worse than the centralized system when the number of locations goes to infinity, although the choice of sales incentive impacts the performance. We develop an upper bound for the decentralized system, where the bound gives insight on the performance of the heuristics in large systems. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

Book reviews

European Security in the New Political Environment by James H. Wyllie, London: Addison, Wesley Longman, 1997, ISBN 0-582-24403-X (pbk), £13.99

Russia and Europe: The Emerging Security Agenda edited by Vladimir Baranovsky, Oxford: Oxford University Press, SIPRI, 1997, ISBN 0-19-829201-5 (hbk), £45.00

The Defeat of Japan by David Rees, Westport, Connecticut and London: Praeger, ISBN 0-275-95955-4 (hbk), £46.50

The Collective Naval Defence of the Empire, 1900-1940 by Nicholas Tracy (ed.), London: Ashgate, for the Navy Records Society, 1997, ISBN 1859-284-027 (hbk), £59.50

Knights in White Armour The New Art of War and Peace by Christopher Bellamy, London: Pimlico Press, 1997, ISBN 0-7126-739-03 (pbk), £12.50

Regional Orders: Building Security in a New World by avid A. Lake and Patrick M. Morgan (eds), University Park: Penn State Press, 1997, ISBN 0-271-01703-i (hbk), £49.50/$55, ISBN 0-271-01704-X (pbk), £7.95/$19.95

Contested Social Orders and International Politics by David Skidmore (ed.), Nashville: Vanderbilt University Press, 1997, ISBN 0-8265-1284-4 (hbk), $32.95

The Politics of Threat: Minuteman Vulnerability in American National Security Policy by David H. Dunn. London: Macmillan Press, 1997, ISBN 0-333-67816-8 (hbk), £45.00

The Sociology of the Military by Guiseppe Caforio (ed.), Cheltenham: Edward Elgar, 1998, ISBN 1-85898-619-2, 704 pp., £150

The Nordic Nations in the New Western Security Regime by Ingemar Dorfer, Baltimore: Johns Hopkins University Press, 1997, ISBN 0-943875-83-8 (hbk), £27, ISBN 0-943875-82-X (pbk), £13     

Design of a process control scheme for defects per 100 units based on aoql

A process control scheme is developed in which decisions as to the frequency of sampling are made based upon the choice of an Average Outgoing Quality Limit. The scheme utilizes plotted points on a U-control chart for defects and the theory of runs to determine when to switch among Reduced, Normal, Tightened, and 100 percent inspection. The scheme is formulated as a semi-Markov process to derive steady stale equations for the probabilities of being in Reduced, Normal, Tightened, or 100 percent inspection and for Average Outgoing Quality and Average Fraction Inspected. The resulting system and the computer programs used to derive it are discussed.