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231.
The subject of this paper is the utilization of the “infant mortality” or decreasing failure rate effect to improve the reliability of repairable devices. Decreasing failure rate implies the possibility that devices which exhibit it can be improved by “burn-in testing” of each unit. Such a test serves to accumulate operating time while shielded from the full costs and consequences of failure. A general formulation of the burn-in test decision for repairable devices is presented and some special cases are solved. A class of models, indexed by the degree of partial replacement present in the repair process, is considered and numerical results for the optimal policy are given for several members of that class. A comparison of those results reveals the profitability of testing increases with the complexity of the repairable device.  相似文献   
232.
A fundamental unsolved problem in the programming area is one in which various activities have fixed charges (e.g., set-up time charges) if operating at a positive level. Properties of a general solution to this type problem are discussed in this paper. Under special circumstances it is shown that a fixed charge problem can be reduced to an ordinary linear programming problem.  相似文献   
233.
The “infant mortality” effect observed in the statistical treatment of reliability consists of a decreasing with age of the conditional probability of equipment failure (failure rate). One widely applicable explanatory hypothesis is that of population heterogeneity. This is developed here as a basis for several specific models of decreasing failure rate processes. Since, in the case of repairable devices, decreasing failure rate is often observed after the occurrence of failure and repair, consideration is extended to include repair in an explicit way. This union of failure and repair models is a fruitful one in view of the interaction between the two processes and gives a complete picture of the life of the device in terms of a stochastic process, usually with non-independent interfailure times. Four models, of particular significance due to their plausibility, mathematical tractability, and frugality of parameterization, are presented.  相似文献   
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This article examines the Dhofar campaign in Oman (1965–75), and the role Britain played in assisting the Omani royal government against left-wing insurgents. Using existing secondary sources and declassified British government papers, it reassesses the contribution of British military advisers and special forces to the counter-insurgency (COIN) campaign, the balance between military action and civil affairs, the external dimension of the conflict, and intelligence and covert operations. It concludes by assessing whether the Dhofar War offers any guidance to Western armed forces involved in contemporary COIN campaigns such as those in Afghanistan and Iraq.  相似文献   
238.
A potentially productive triangular arrangement among Russia, Ukraine, and the United States emerged in 1994 from efforts to constrain nuclear weapons diffusion. By 2001, this promising initiative was nearly moribund, owing to the inability or unwillingness of the parties to fulfill the commitments of subsequent agreements. The domestic and external causes of this failure are many and clear. Yet the advantages to each of reengaging in a trilateral relationship are also plain. This means fulfilling their unfinished agenda by learning from past mistakes, adopting realistic premises and goals, and pursuing ‘bottom up’ as well as ‘top down’ strategies.  相似文献   
239.
From 1956 to 1960, the French Army developed a force of Muslim auxiliaries (supplétifs) as a major component of its strategy to combat the National Liberation Front (FLN) insurgency in Algeria. Aside from their military utility in hunting down the guerrillas in the mountains and forests, the supplétifs were instrumental in undermining FLN legitimacy in the countryside. The rapid growth and employment of the supplétif force dismantled FLN political control in the villages, undermined the enemy's unity, and critically weakened the revolutionaries' claim to represent all of Algeria's Muslims. The military and political activities of France's Muslim soldiers also projected an image of Muslim–European unity behind the French cause, and portrayed the French Army as the only legitimate political force in numerous villages. These political successes, however, were limited to the local, tactical level of revolutionary warfare, and the Army was never able to convert the supplétifs into a force of decisive, strategic political significance. They thus had little ultimate impact on the outcome of the conflict.  相似文献   
240.
Soon after India attained its independence from British colonial administration in 1947 the Nagas started waging an armed conflict against India to establish a sovereign independent state in Nagaland in the country's Northeast region. The conflict is today one of the world's longer running and little known armed conflicts. India's central government has tried unsuccessfully to tackle the problem through political reconciliation, use of force, and several development measures. Over the years, it has also undergone several changes in which the situation of conflict deepened whenever India's central government intervened. And yet, the road ahead also faces severe challenges because the demand for bringing the Nagas of India together into a single political entity will not go unchallenged from other ethnic groups. Moreover, a bitter leadership battle divides the Naga rebels and hence any future agreement is likely to be difficult due to factional politics as have happened in the past. Thus one way to satisfy the aspirations of different ethnic groups while protecting the boundaries of the existing states in India is to explore the option of cultural autonomy. This idea is not entirely new, but has lost significance over the years.  相似文献   
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