Optimal policies for M/M/m queue with two different kinds of (N,T)‐policies

In this paper, two different kinds of (N, T)‐policies for an M/M/m queueing system are studied. The system operates only intermittently and is shut down when no customers are present any more. A fixed setup cost of K > 0 is incurred each time the system is reopened. Also, a holding cost of h > 0 per unit time is incurred for each customer present. The two (N, T)‐policies studied for this queueing system with cost structures are as follows: (1) The system is reactivated as soon as N customers are present or the waiting time of the leading customer reaches a predefined time T, and (2) the system is reactivated as soon as N customers are present or the time units after the end of the last busy period reaches a predefined time T. The equations satisfied by the optimal policy (N*, T*) for minimizing the long‐run average cost per unit time in both cases are obtained. Particularly, we obtain the explicit optimal joint policy (N*, T*) and optimal objective value for the case of a single server, the explicit optimal policy N* and optimal objective value for the case of multiple servers when only predefined customers number N is measured, and the explicit optimal policy T* and optimal objective value for the case of multiple servers when only predefined time units T is measured, respectively. These results partly extend (1) the classic N or T policy to a more practical (N, T)‐policy and (2) the conclusions obtained for single server system to a system consisting of m (m ≥ 1) servers. © 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 240–258, 2000     

潜艇信息系统信息安全与纵深防护策略研究

随着网络中心战的发展,信息安全问题在现代潜艇系统中的重要性日益凸显。首先分析潜艇信息安全问题的背景、总结其研究现状,然后研究了潜艇信息安全需求及属性定义,探讨了潜艇信息系统信息安全防护整体框架,在此基础上提出了一种综合静态安全防护和动态运行安全防护的潜艇信息系统信息安全纵深防护体系结构。以期为解决潜艇系统设计中的安全缺陷、建立潜艇信息安全防护体系,辅助系统维护、保障系统安全提供基础。     

National security,military spending and the business cycle

This paper develops a Dynamic Stochastic General Equilibrium model where national security is an argument in the agent’s utility function and the government chooses optimally the level of military spending to maximize social welfare. National defense depends on military expenditure and on the strategic environment reflecting a potential hostile external threat. We use aggregate data on consumption, investment, and military spending for the US economy to estimate the parameters of the model. Estimation results suggest that consumption and national defense are complements and that military spending variability is mainly explained by external threat shocks although it also depends on the macroeconomic conditions. We compute impulse response functions of the main macroeconomic variables to several shocks: a total factor productivity shock, a defense technology shock, and a strategic environment shock. Surprisingly, we find that the optimal response to an increase in the external threat (a worsening in the strategic environment) will rise output by reducing consumption and increasing investment.     

Introduction

ABSTRACT

The new nuclear history can make a critical contribution by forcing us to reconsider or reframe the theoretical premises of the concepts we apply to our understanding of the present – and with which we try to navigate the future. It bears on fundamental questions, such as: How should the US manage its alliances? Should it establish a multilateral nuclear policy dialogue in Asia? In what depth should it discuss issues of doctrine and targeting with its Asian allies? What capabilities might reassure European allies in light of current Russian revisionism? Could nuclear war be limited and controlled in an East Asian maritime arena? Do nuclear weapons strengthen an alliance, or do they introduce a divisive bone of contention? Is extended nuclear deterrence (END) stabilizing or is it on the contrary pushing the allies to ask for more? What is the relationship between nuclear and conventional forces in END credibility? How do nuclear alliances contribute to international security and international order? The lessons and insights from these papers, which look at five historical cases of US extended deterrence during the Cold War, should help us think about crucial current issues, and be of use both to historians who want to have a better understanding of the Cold War past and to policymakers who are currently grappling with these issues.     

对高等教育若干问题的思考

目前高等教育中存在的种种弊端,迫使高等教育必须改革。高等教育决不能脱离党的教育方针,要强化世界观和价值观教育,远离社会不良风气的干扰,培养出德智体全面发展的人才。     

公安边防部队士官学历教育浅谈

公安边防部队的士官学历教育尚在起步阶段,任重而道远。各级领导应着眼部队长远建设,确立优先发展的战略地位;应立足部队现实需要,设置学科专业;应根据岗位任职需求,确定课程体系,突出实用性;应适应教学任务的要求,完善管理与保障体系。     

论公安现役高校在构建和谐社会中的角色定位

公安现役高校在公安教育体系中处于重要位置,承担着人才培养、科学研究和服务部队的重要任务,对构建和谐社会责无旁贷。准确定位公安现役高校在构建和谐社会中所扮演的角色,可以充分发挥职能作用,为构建和谐社会做出应有贡献。     

构建和谐社会之法律思想透析

实现社会和谐始终是人类追求的一个社会理想,只是因为社会历史的不同,和谐社会思想所包含的要义以及所追求的目标也随之有所差异。但法之于和谐社会具有重要价值却是绝大多数法哲学家所认同的,即构建和谐社会离不开法律保障之基石。从中西方法律思想以及可持续发展观角度层层递进,对构建和谐社会之合理性、时代性、先导性以及法之于和谐社会的重要价值进行探讨与思索。     

公安系统科研成果管理的信息化解决方案

针对公安科研工作的现状及特点,提出了适合公安科技管理部门进行信息化管理的信息系统解决方案。简要分析了系统需求,从系统数据流程、软件结构及功能框架、实现方案、系统安全保密架构几方面设计了系统体系结构,为公安科研工作提供了统一的科研成果信息化管理平台。     

再论加强公安执法人员的法治观念

法制现代化是中国当前重大的社会主题之一,它是一个历史的、发展的过程。公安法治建设必然对国家法制现代化进程产生重大的影响。公安机关的性质、地位和作用决定了公安执法人员必须具有正确的执法思想。而法律至上观念、权利本位观念、分权制衡观念、正当程序观念对公安执法人员正确执法思想的形成有着直接的影响。