Markovian approximation for manufacturing systems of unreliable machines in tandem

This paper studies production planning of manufacturing systems of unreliable machines in tandem. The manufacturing system considered here produces one type of product. The demand is assumed to be a Poisson process and the processing time for one unit of product in each machine is exponentially distributed. A broken machine is subject to a sequence of repairing processes. The up time and the repairing time in each phase are assumed to be exponentially distributed. We study the manufacturing system by considering each machine as an individual system with stochastic supply and demand. The Markov Modulated Poisson Process (MMPP) is applied to model the process of supply. Numerical examples are given to demonstrate the accuracy of the proposed method. We employ (s, S) policy as production control. Fast algorithms are presented to solve the average running costs of the machine system for a given (s, S) policy and hence the approximated optimal (s, S) policy. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 65–78, 2001     

The crisis of American military assistance: strategic dithering and Fabergé Egg armies

ABSTRACT

The United States has provided substantial amounts of military assistance and aid since the end of World War Two. During the Cold War, it proved vital in protecting numerous regimes from communist takeovers. Successful outcomes occurred when American leaders made large initial aid commitments, and the states had the capacity and political willpower to use it effectively. However, Vietnam was an example of how U.S. support lagged, as leaders in Saigon preferred political survival instead of creating regime legitimacy. Following 9/11, American security aid focused on making weak countries develop stronger security forces. Unfortunately, this created Fabergé egg militaries: expensive and easily broken by insurgents. This article suggests long-term strategic commitments need to be made alongside more resources for the American State Department and similar organizations to focus on the politics of state-building. Finally, this article suggests strategies, such as “whole-of-government” approaches, to improve long-term security and political institution building.     

Tilting at windmills: The flawed U.S. policy toward the 1971 Indo-Pakistani war

ABSTRACT

This article examines decision-making mistakes made by U.S. President Nixon and national security advisor Kissinger during the 1971 India-Pakistan crisis and war. It shows that Nixon and Kissinger routinely demonstrated psychological biases that led them to overestimate the likelihood of West Pakistani victory against Bengali rebels as well as the importance of the crisis to broader U.S. policy. The evidence fails to support Nixon and Kissinger’s own framing of the 1971 crisis as a contest between cool-headed realpolitik and idealistic humanitarianism, and instead shows that Kissinger and Nixon’s policy decisions harmed their stated goals because of repeated decision-making errors.     

基于混响室的雷达回波传输环境模拟

为检验雷达回波传输质量,完成基于莱斯因子K的混响室电磁环境分级,提出混响室条件下雷达回波传输环境模拟评价参数信杂比S,对比分析莱斯因子K和信杂比S的测量原理．实验结果表明：混响室可用于雷达回波传输环境模拟．     

Dundee-made harpoon gun associated with H. M. S. Challenger

Attention is drawn to the existence of a harpoon-gun putatively from H. M. S. Challenger, a ship whose three-and-a-half-year circumnavigation of the globe (1872–1876), marked the beginning of the science of oceanography. The harpoon gun in question was made by Dundee shipsmith and harpoon-gun maker, David Neave. Only a few other examples of his work are known to exist and this example with a Remington rolling-block action is unusual for a British harpoon gun. It is proposed that it came to Millport's Marine Station via links Sir John Murray (1841–1914) had with the Marine Biological Association of the West of Scotland.     

Country Survey XIII: Japan's security posture and defense industry prospects

Defense budgets in Japan have been complicated compromises from numerous inputs ‐ including threat perceptions, domestic industrial/technological base development, support for the bilateral security treaty with the United States and internal bureaucratic politics ‐ but with the fall of the former Soviet Union, the clearest justification for higher spending disappeared. Double‐digit defense spending increases that were common in the 1980s have been replaced by annual increases lower than present inflation rates, resulting in negative real growth in the country's defense budget. Domestic economic problems and consistent government pressures for smaller budgets have further slowed annual growth in total spending and have contributed to lower procurement budgets. As a result, the domestic Japanese defense industry is facing far more constrained conditions from the growth years of a decade before.

Government policymakers are examining Japan's regional security environment as well as its alliance with the United States to determine the appropriate course for the country to take in the coming years. The formal security treaty with the United States is likely to remain a major element of government positions, but other aspects of the country's overall security posture are open to debate. Perceptions of a reduced threat environment are fueling additional pressures for defense budget cuts.

The domestic defense industry seeks means to assure its survival in domestic defense markets in this constrained environment. Expansion into overseas markets to offset declining domestic markets is an option that currently is constrained by policy restrictions on arms exports. Industry is advocating re‐examination of those policies and unlike earlier years, government appears willing to respond positively but cautiously to this lobbying.     

The Dilemmas of US Maritime Supremacy in the Early Cold War

After World War II, the US Navy confronted the challenge of adapting to dramatically altered geopolitical circumstances. Moscow did not have an ocean-going fleet, and early Cold War strategy was dominated by the salient position of nuclear strategic bombing – a mission thought to be outside the purview of the navy. Traditional roles, such as protecting sea lines of communication and supporting ground forces ashore, quickly proved indispensable. However, the navy eventually also succeeded in fielding dramatic technological and institutional innovations, for example, the strategic missile submarine, which enabled the US to successfully leverage maritime power against the continental power of the USSR.     

数据库课程设计网络教学平台的设计与研究

网络教育是建立在网络技术平台上,利用网络环境所进行的教育、教学活动;网络课程是通过网络表现教学内容及实施的教学活动的总和。详细介绍了《数据库课程设计》网络教学平台的设计实现及主要功能。     

美国2014年《四年防务评估报告》特点

2014年3月4日,美国国防部向国会提交了2014年版《四年防务评估报告》和《2015财年国防预算报告》。《四年防务评估报告》更新了再平衡战略,为美军建设提出了优先发展方向,要求美军联合部队向“更小型化”转型,以满足未来军事行动需求。     

美国网络霸权对中国国家安全的影响及对策

随着互联网对现实世界的影响越来越大,战略地位越来越突出,获得网络主导权、占据网络制高点成为各国竞相努力的目标。美国在全球网络管理、网络技术、网络文化、网络军事等方面处于霸主地位。美国网络霸权对中国的政治安全、信息安全、文化安全、军事安全造成了极大的威胁。中国应综合采取各种措施,应对美国网络霸权的冲击和挑战,维护国家安全和利益。