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81.
We consider the problem of finding the system with the best primary performance measure among a finite number of simulated systems in the presence of a stochastic constraint on a single real‐valued secondary performance measure. Solving this problem requires the identification and removal from consideration of infeasible systems (Phase I) and of systems whose primary performance measure is dominated by that of other feasible systems (Phase II). We use indifference zones in both phases and consider two approaches, namely, carrying out Phases I and II sequentially and carrying out Phases I and II simultaneously, and we provide specific example procedures of each type. We present theoretical results guaranteeing that our approaches (general and specific, sequential and simultaneous) yield the best system with at least a prespecified probability, and we provide a portion of an extensive numerical study aimed at evaluating and comparing the performance of our approaches. The experimental results show that both new procedures are useful for constrained ranking and selection, with neither procedure showing uniform superiority over the other.© 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010 相似文献
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MacGregor and Harris (J Quality Technol 25 (1993) 106–118) proposed the exponentially weighted mean squared deviation (EWMS) and the exponentially weighted moving variance (EWMV) charts as ways of monitoring process variability. These two charts are particularly useful for individual observations where no estimate of variability is available from replicates. However, the control charts derived by using the approximate distributions of the EWMS and EWMV statistics are difficult to interpret in terms of the average run length (ARL). Furthermore, both control charting schemes are biased procedures. In this article, we propose two new control charts by applying a normal approximation to the distributions of the logarithms of the weighted sum of chi squared random variables, which are respectively functions of the EWMS and EWMV statistics. These new control charts are easy to interpret in terms of the ARL. On the basis of the simulation studies, we demonstrate that the proposed charts are superior to the EWMS and EWMV charts and they both are nearly unbiased for the commonly used smoothing constants. We also compare the performance of the proposed charts with that of the change point (CP) CUSUM chart of Acosta‐Mejia (1995). The design of the proposed control charts is discussed. An example is also given to illustrate the applicability of the proposed control charts. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009 相似文献
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In this article, we study a two‐level lot‐sizing problem with supplier selection (LSS), which is an NP‐hard problem arising in different production planning and supply chain management applications. After presenting various formulations for LSS, and computationally comparing their strengths, we explore the polyhedral structure of one of these formulations. For this formulation, we derive several families of strong valid inequalities, and provide conditions under which they are facet‐defining. We show numerically that incorporating these valid inequalities within a branch‐and‐cut framework leads to significant improvements in computation. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 647–666, 2017 相似文献
84.
We consider scheduling problems involving two agents (agents A and B), each having a set of jobs that compete for the use of a common machine to process their respective jobs. The due dates of the A‐jobs are decision variables, which are determined by using the common (CON) or slack (SLK) due date assignment methods. Each agent wants to minimize a certain performance criterion depending on the completion times of its jobs only. Under each due date assignment method, the criterion of agent A is always the same, namely an integrated criterion consisting of the due date assignment cost and the weighted number of tardy jobs. Several different criteria are considered for agent B, including the maxima of regular functions (associated with each job), the total (weighted) completion time, and the weighted number of tardy jobs. The overall objective is to minimize the performance criterion of agent A, while keeping the objective value of agent B no greater than a given limit. We analyze the computational complexity, and devise polynomial or pseudo‐polynomial dynamic programming algorithms for the considered problems. We also convert, if viable, any of the devised pseudopolynomial dynamic programming algorithms into a fully polynomial‐time approximation scheme. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 416–429, 2016 相似文献
85.
Column generation for stochastic green telecommunication network planning with switchable base stations
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We present the green telecommunication network planning problem with switchable base stations, where the location and configuration of the base stations are optimized, while taking into account uncertainty and variability of demand. The problem is formulated as a two‐stage stochastic program under demand uncertainty with integers in both stages. Since solving the presented problem is computationally challenging, we develop the corresponding Dantzig‐Wolfe reformulation and propose a solution approach based on column generation. Comprehensive computational results are provided for instances of varying characteristics. The results show that the joint location and dynamic switching of base stations leads to significant savings in terms of energy cost. Up to 30% reduction in power consumption cost is achieved while still serving all users. In certain cases, allowing dynamic configurations leads to more installed base stations and higher user coverage, while having lower total energy consumption. The Dantzig‐Wolfe reformulation provides solutions with a tight LP‐gap eliminating the need for a full branch‐and‐price scheme. Furthermore, the proposed column generation solution approach is computationally efficient and outperforms CPLEX on the majority of the tested instances. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 351–366, 2016 相似文献
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Edward Katumba‐Wamala 《Small Wars & Insurgencies》2013,24(3):160-171
Africa has had no shortage of guerrilla movements since 1975. However, very few have been successful that have not fought against European colonial rule or white minority regimes. Fundamentally, without external support, these movements have been almost universally failures. One major exception to this rule was the National Resistance Army of Uganda, which overthrew the regime led by General Tito Okello in 1986. What made the National Resistance Army a success and distinct from other guerrilla armies were its sound leadership, its superior organization and its creative strategy. 相似文献
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David A. Charters Sam C. Sarkesian Daniel W. Fitz‐Simons 《Small Wars & Insurgencies》2013,24(2):280-286
A. Hamish Ion and E.J. Errington (eds.), Great Powers and Little Wars: the Limits of Power. Westport, CT: Praeger, 1993. Pp.246, select biblio, index. $49.95. ISBN 0275–93965–0 John M. Rothgeb, Jr., Defining Power: Influence and Force in the Contemporary International System. New York: St. Martin's Press, 1993. Pp.205. $39.95 (hbk); $18.70 (pbk). ISBN 0312–086–822 and 061–056 Brian L. Job (ed.), The Insecurity Dilemma: National Security in Third World States. Boulder, CO: Lynne Rienner Publishers, 1992, Pp.257. $37. ISBN 1–55587–267–0 Edwin G. Corr and Stephen Sloan (eds.), Low‐Intensity Conflict: Old Threats in a New World. Westview Studies in Regional Security, Boulder, CO: Westview, 1992. Pp.310, maps, figures, index. $55 (hbk); $18.85 (pbk). ISBN 0–8133–8593–8 and 8594–6 相似文献
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Uri Bar‐Joseph 《战略研究杂志》2013,36(3):46-66
According to common wisdom, the Golan provides Israel with an ideal platform for its warning stations as well as the best available defense line against a massive Syrian ground attack. Challenging this belief, this article compares the present situation with an alternative defined by (a) a complete Israeli withdrawal from the Golan, (b) a complete demilitarization of the evacuated territory, and (c) considerable limitations on Syrian military presence in the area between the Golan and Damascus. The article reaches two conclusions. First, that a combination of means, primarily airborne and space‐based platforms, can effectively answer Israel's northern intelligence needs. Second, the security arrangements set above, combined with recent revolutionary military technologies and its relative advantage in this domain, offer Israel an effective ‐ in some respects even a better ‐ alternative, to the present defense line. 相似文献
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