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We consider the infinite horizon serial inventory system with both average cost and discounted cost criteria. The optimal echelon base‐stock levels are obtained in terms of only probability distributions of leadtime demands. This analysis yields a novel approach for developing bounds and heuristics for optimal inventory control polices. In addition to deriving the known bounds in literature, we develop several new upper bounds for both average cost and discounted cost models. Numerical studies show that the bounds and heuristic are very close to optimal.© 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007 相似文献
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基于改进局部投影算法的非线性时间序列降噪 总被引:1,自引:0,他引:1
改进了非线性时间序列降噪的局部投影算法,并应用此算法对含噪Lorenz混沌信号进行降噪,将其与小波分析降噪效果进行比较,实验结果表明:改进的局部投影算法对非线性信号降噪效果十分明显。 相似文献
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Antonio Giustozzi 《Small Wars & Insurgencies》2017,28(1):12-33
Although the Taliban insurgency was internally divided and unable to coordinate its activities in 2014–2015, the Afghan security forces were not able to contain it and steadily lost ground throughout 2015. Until 2015, there had been little effort to develop an indigenous Afghan counterinsurgency strategy, but a sense of urgency emerged after a string of Taliban victories. At the beginning of 2016, it was still not clear if and when the National Unity Government would be able to produce a counterinsurgency strategy and, in any case, the need for a coherent counterinsurgency approach became questionable as the Taliban appeared to be transitioning towards conventional warfare. 相似文献
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Ian Westerman 《Defense & Security Analysis》2017,33(3):276-288
The existing guidelines for security sector reform (SSR) tend to draw on theoretical work in the field of civil–military relations, which in turn has been derived from Western, liberal democratic models of governance. Although guidelines strongly advise that local culture and context need to be considered when drawing up objectives for post-conflict SSR programmes, this is not often reflected in practice. This article considers some of the reasons for this, citing both in-country challenges and donor-related issues, and suggests that one of the biggest problems is a lack of alternative, non-orthodox models of civil–military relations to draw upon. It is further suggested that elements of suitable alternative models may be found in states which possess political structures not entirely dissimilar to the Western, liberal democratic ideal, but which can offer different perspectives. Detailed research of these structures should produce a pool of sub-models which could then be employed to create bespoke, culturally appropriate objectives for use in post-conflict SSR programmes. 相似文献
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Nadine Ansorg 《Contemporary Security Policy》2017,38(1):129-144
Many African states have security sector reform (SSR) programs. These are often internationally funded. But how do such programs account for previously existing security institutions and the security needs of local communities? This article examines SSR all over Africa to assess local ownership and path dependency from a New Institutionalist perspective. It finds that SSR, particularly in post-conflict countries, tends to be driven by ideas and perceptions of international donors promoting generalized blueprints. Often, such programs only account in a very limited way for path-dependent aspects of security institutions or the local context. Hence, the reforms often lack local participation and are thus not accepted by the local community eventually. 相似文献
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针对蚁群算法求解CVRP问题时收敛速度慢、求解质量不高的缺点,提出了一种改进启发式蚁群算法。该算法借鉴蚁群系统和基于排列的蚂蚁系统的优点设计信息素更新策略,既加强了对每次迭代最好解的利用,又避免了陷入局部最优;按一定比例使用基本方法和基于PFIH方法构造路径,扩大了算法的搜索空间;采用一种混合局部搜索算子,增强了算法局部寻优能力。实验结果表明,改进启发式蚁群算法可以大幅度减少车辆运行成本,具有较快的收敛速度。 相似文献
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Sheldon M. Ross 《海军后勤学研究》2015,62(8):659-663
There are n customers that need to be served. Customer i will only wait in queue for an exponentially distributed time with rate λi before departing the system. The service time of customer i has distribution Fi, and on completion of service of customer i a positive reward ri is earned. There is a single server and the problem is to choose, after each service completion, which currently in queue customer to serve next so as to maximize the expected total return. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 659–663, 2015 相似文献
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冯春波 《兵团教育学院学报》2012,(6):77-79
文化交流可以促进相互了解、共同繁荣。文化没有优劣之分,因此,文化交流应该是平衡的。这种交流离不开翻译。翻译教学是培养翻译人才的主要手段。教材是教学三要素之一,其重要性自不待言。我们目前的翻译教材在很大程度上仍然偏重文学,忽略实用文体的翻译,而且不可能顾及各地文化,因此在利用现有的翻译教材进行翻译教学时,有必要增加本地文化的翻译内容。兵团文化是一种崭新、独特的文化,更有必要在翻译教学中占有一席之地。 相似文献
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为了提高漏磁检测的灵敏度,利用ANSYS软件建立了漏磁检测励磁装置的三维有限元模型,研究了钢板的厚度、永磁体厚度、磁极面积以及磁化间隙等因素对钢板局部磁化效果的影响,得到了钢板磁化强度随永磁体几何参数改变时的变化规律,提出了永磁磁化方式下励磁装置优化设计的基本方法,对励磁装置各部分参数进行了优化设计.实验证明,优化设计的励磁装置能改善磁化效果,提高检测灵敏度. 相似文献