The stochastic single resource service‐provision problem

The service‐provision problem described in this paper comes from an application of distributed processing in telecommunications networks. The objective is to maximize a service provider's profit from offering computational‐based services to customers. The service provider has limited capacity and must choose which of a set of software applications he would like to offer. This can be done dynamically, taking into consideration that demand for the different services is uncertain. The problem is examined in the framework of stochastic integer programming. Approximations and complexity are examined for the case when demand is described by a discrete probability distribution. For the deterministic counterpart, a fully polynomial approximation scheme is known 2 . We show that introduction of stochasticity makes the problem strongly NP‐hard, implying that the existence of such a scheme for the stochastic problem is highly unlikely. For the general case a heuristic with a worst‐case performance ratio that increases in the number of scenarios is presented. Restricting the class of problem instances in a way that many reasonable practical problem instances satisfy allows for the derivation of a heuristic with a constant worst‐case performance ratio. Worst‐case performance analysis of approximation algorithms is classical in the field of combinatorial optimization, but in stochastic programming the authors are not aware of any previous results in this direction. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2003     

指挥控制系统服务化研究

网络化体系作战是军队未来主要的作战样式,面向服务的指挥控制系统是实施网络化指挥控制的技术基础,是网络化指挥控制系统的重要特征.分析了指挥控制系统服务化的原因,阐述了面向服务的指挥控制系统的特点和面临的问题,提出了实现指控系统服务化的关键技术.     

国外消防中介组织运作模式及启示

介绍了美国、加拿大、俄罗斯、德国、日本等国消防中介组织运作模式概况及特点,提出了其对我国消防中介组织发展的启示。     

中学作文教学八法

作文是中学语文教学的重要内容,也是学生学习比较困难的学科,如何教好学生写作,是语文教师长期探讨的问题,本文是作者长期从事中学作文教学的实践总结,提出作文的八种教学方法。     

面向服务的遗留系统再工程过程

将遗留系统再工程为面向服务系统是软件技术发展的趋势,但现有软件过程不能很好地解决面向服务的再工程所面临的问题.比如如何协调遗留系统共利益者的交流并快速有效地处理需求变更;如何实现服务以满足目标系统体系结构灵活性;如何降低重用遗留系统带来的风险以及如何减少交付期的软件错误等.针对这些问题,设计了面向服务的遗留系统再工程过程(SORP).SORP融合了传统软件过程的计划性和灵活性,并根据面向服务再工程项目的特点进行了特殊配置,在生命周期上将再工程过程划分为四个阶段,在内容上包含了六个工作流.为与实践相结合,详细规划了SORP的角色、活动、工作产品以及评估方法.应用实践表明,SORP在一定程度上增加了目标系统体系结构的灵活性,降低了重用遗留系统带来的风险.     

谈新闻媒体对警卫工作的影响

警卫工作与新闻媒体有着广泛的联系,新闻媒体对警卫工作具有重大影响,警卫部门要科学利用新闻媒体,充分发挥其积极作用。     

做好奥运出入境边防检查工作之管见

确保奥运会安全、顺利、成功举办,是当前压倒一切的政治任务,全国边防检查机关广大官兵要提高思想认识,加强组织领导,加大各项工作力度,真正做到“服务更加亲切,管控更加严密”,推动边检服务工作再上新台阶。     

一种完全分布式的空间服务及组合模型

针对服务组合中控制流和数据流的不同协调机制,可将组合模型分为4种类型,分别是控制流集中式且数据流集中式、控制流集中式且数据流分布式、控制流分布式且数据流集中式、控制流分布式且数据流分布式.空间服务组合流程需处理较大规模的数据流,采用控制流分布式和数据流分布式的协调机制能有效降低组合过程中系统整体通信规模并减少空间服务组合响应时间.通过对各种不同组合类型建模的定量分析对上述观点进行了正确性论证.模拟实验证明,定量分析结果可信.     

BOOK REVIEWS

This study examines how young people who have joined the South African National Defence Force (SANDF) on the two-year Military Skills Development System (MSDS) contract experience military service, and the effect this has on their ability to readapt to civilian life. The first part of the study examines the theoretical debates associated with military socialisation and reintegration into civilian life. Hereafter, the findings are presented in terms of the experiences of MSDS privates serving in the infantry, those that have left, and the perceptions of employment agencies in terms of the marketability of military skills. The conclusion is reached that MSDS members experience their two years in the SANDF as life-changing, that this affects their ability to reintegrate back into civilian society, and that the skills acquired during military training is of limited market value. The conclusion is reached that more needs to be done to assist these young military veterans to adapt to civilian life and to augment their military experience with more marketable skills to enable them to find gainful employment.