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This paper proposes a new appointment rule for the single-server, multiple-customer service system. Unlike previous appointment rules, which perform well only in specific service environments, the new rule can be parameterized to perform well in different service environments. The new appointment rule is presented as a mathematical function of four environmental parameters, namely, the coefficient of variation of the service time, the percentage of customers' no-shows, the number of appointments per service session, and the cost ratio between the server's idle and customers' waiting cost per unit time. Once the values of these environmental parameters are estimated, the new appointment rule can be parameterized to perform well. The results show that new rule performs either as well as or better than existing appointment rules in a wide range of service environments. © 1998 John Wiley & Sons, Inc. Naval Research Logistics 45: 313–326, 1998 相似文献
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新中国成立60年来,国防战略先后做过4次重大调整.每一次调整既始终贯彻了积极防御这一新中国国防战略的本质要素,又与当时中国国家安全环境以及国家发展战略密切相关,有着明显的时代特征,显示了新中国国防战略的日臻成熟. 相似文献
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This article aims to analyze the Brazilian Defense Policy in terms of its ability to reduce the gap between ends and means. Since 2003, the Brazilian defense policy has evolved along with Brazil’s increased role in the international system. Sustaining this process depends on institutional, economic, and operational conditions that are yet to be fully guaranteed. They require negotiations, reforms, and strategic perspective. By identifying specific challenges emerging from the national security institutional framework, the combat capability building process, the budgetary cycle, as well as from the defense industrial base, we sought to explain their rationale and to offer concrete policy pointers to overcome obstacles. As a general conclusion, the Brazilian defense policy was strengthened by the 2008 National Defense Strategy (END) due to its clearer strategic goals. Bridging the gap between those ends and the proper means is a continuous effort for any given country, but in the case of Brazil it has been addressed with firmer steps since the END, even in the face of harder economic and political conditions. 相似文献
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In this article, an optimal replacement policy for a cold standby repairable system consisting of two dissimilar components with repair priority is studied. Assume that both Components 1 and 2, after repair, are not as good as new, and the main component (Component 1) has repair priority. Both the sequence of working times and that of the components'repair times are generated by geometric processes. We consider a bivariate replacement policy (T,N) in which the system is replaced when either cumulative working time of Component 1 reaches T, or the number of failures of Component 1 reaches N, whichever occurs first. The problem is to determine the optimal replacement policy (T,N)* such that the long run average loss per unit time (or simply the average loss rate) of the system is minimized. An explicit expression of this rate is derived, and then optimal policy (T,N)* can be numerically determined through a two‐dimensional‐search procedure. A numerical example is given to illustrate the model's applicability and procedure, and to illustrate some properties of the optimal solution. We also show that if replacements are made solely on the basis of the number of failures N, or solely on the basis of the cumulative working time T, the former class of policies performs better than the latter, albeit only under some mild conditions. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010 相似文献
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20世纪六七十年代,新中国面对严峻的国家安全形势,曾进行了一场大规模的战备.这次战备以"早打、大打、打核战争"为指导思想,将战备工作在一个相当长的时期内摆在全党、全军乃至全国各项工作的中心地位,并制约国家各项工作的安排和开展,与一般意义上的战备相比显示出特殊的复杂性.因而,这一时期的战备备受争议,可谓众说纷纭、褒贬不一. 相似文献
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