改善热带海域船用主机热负荷的研究

本文以8NVD48A—2u柴油机为例,针对船用发动机在热带海域热负荷过高问题进行了研究,并提出了改进方案。通过实船改装和调试,降低了柴油机的排温,改善了燃烧,收到好的效果。     

指挥控制通信与情报系统(C3I)

本文是一篇关于C~3I系统的概述。它介绍了C~3I的各组成部分以及这些部分是如何组成一个系统的。另外,讨论了几个与C~3I系统有关的技术问题。     

Minimizing mean absolute deviation of completion times about a common due date

We consider a single machine scheduling problem in which the objective is to minimize the mean absolute deviation of job completion times about a common due date. We present an algorithm for determining multiple optimal schedules under restrictive assumptions about the due date, and an implicit enumeration procedure when the assumptions do not hold. We also establish the similarity of this problem to the two parallel machines mean flow time problem.     

Book reviews

Exporting Democracy: Fulfilling America's Destiny. By Joshua Muravchik, American Enterprise Institute (1991) ISSN 0–8447–3734–8. $12.95.

Generals in the Palacio. By Roderick Ai Camp. Oxford University Press, (1992), ISBN 0–19–507300–2, £45.

L'Armement en France. Genèse, Ampleur et Coût d'une Industrie By François Chesnais and Claude Serfati, Editions Nathan, Collection Economie/Sciences Sociales, Paris (1992), ISBN 2–09–190086–9.

The Têt Offensive. Intelligence Failure in War. By James Wirtz, Cornell University Press, New York (1991), ISBN 0–8014–2486–0. $38.50.

Restructuring of arms producton in Western Europe. Edited by Michael Brzoska and Peter Lock. Oxford University Press, Oxford (1992), ISBN 0–1982–9147–7. £25.00.

What is Proper Soldiering? A study of new perspectives for the future uses of the Armed Forces of the 1990s. By Michael Harbottle. The Centre for International Peacebuilding, Chipping Norton (1992), £3.50.

The Strategic Defence Initiative By Edward Reiss, Cambridge University Press, Cambridge (1992), ISBN 0–521–41097–5. £30.00.     

模块结构EMS 型磁浮列车的导向控制研究

本文研究了模块结构ＥＭＳ型磁浮列车中的一对相互错开的电磁铁的导向模型,采用衰减记忆算法实施导向控制,通过仿真比较了主动控制系统与自稳定系统的导向效果,讨论了导向控制对纵向悬浮的影响     

视觉导航自主车方向控制系统性能仿真分析

本文主要通过图形仿真的方法对基于视觉导航的自主车（ＡＬＶ）方向控制系统进行性能分析,以大量仿真结果分析各组成子系统对整个系统性能的影响,为系统设计提供理论依据     

毁歼概率积分的高精度计算

精确地计算武器系统对目标的毁歼概率是重要的。在对几种数值积分方案比较的基础上,证明了Ｇａｕｓ－Ｈｅｒｍｉｔ数值积分方案可以最少的积分点达到最高的精度,并以此方案计算了各个参数对毁歼概率的影响     

气隙磁密3次谐波对电机振动噪声的影响

针对电机的电磁振动噪声问题,发现了提高电机气隙磁密的正弦性不一定能够降低电机的振动噪声。鉴于此,分析了引起电机振动和噪声的主要力波阶次和频率,并探究了气隙磁密3次谐波与电机振动噪声的具体函数关系。为了分析引起电机振动和噪声的主要力波阶次和频率,在利用解析法的基础上排出力波表,确定了主要噪声源。为了探究气隙磁密3次谐波对电机振动噪声的影响,建立了气隙磁密及径向力波的数学模型,并通过遗传算法求解了电机气隙磁密3次谐波的最佳幅值。分析结果显示,提高气隙磁密正弦性不一定能够降低电机振动噪声,气隙磁密3次谐波在一定范围内存在最优值使得电机振动噪声最小。分析结果为低噪声电机的设计提供了参考依据。     

A dual criteria sequencing problem with earliness and tardiness penalties

We consider the problem of sequencing n jobs on a single machine, with each job having a processing time and a common due date. The common due date is assumed to be so large that all jobs can complete by the due date. It is known that there is an O(n log n)‐time algorithm for finding a schedule with minimum total earliness and tardiness. In this article, we consider finding a schedule with dual criteria. The primary goal is to minimize the total earliness and tardiness. The secondary goals are to minimize: (1) the maximum earliness and tardiness; (2) the sum of the maximum of the squares of earliness and tardiness; (3) the sum of the squares of earliness and tardiness. For the first two criteria, we show that the problems are NP‐hard and we give a fully polynomial time approximation scheme for both of them. For the last two criteria, we show that the ratio of the worst schedule versus the best schedule is no more than . © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 422–431, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10020     

试论我国高校就业指导体系的建构问题

从二十世纪八十年代开始,我国对普通高校教育体制进行改革,并取得很大成绩,使高等教育的规模有了跨越式的发展,质量与效益也同时大幅度提高。1999年开始的连续几年高校扩招使我国的高等教育从"精英化高等教育"快速步入"大众化高等教育"时代,但同时也使扩招后毕业生的就业成为亟待解决的问题。高校毕业生就业率成为对高校培养人才质量的检验指标,以及对高校社会适应性的检验指标,与学校的生存与发展紧密相连。面对产业结构的调整和高校毕业生大幅度增加的双重压力,高校就业指导工作日显重要,建立一支高水准,高效率的就业指导队伍成为高校建设中应优先解决的问题之一。