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431.
We address the so‐called maximum dispersion problems where the objective is to maximize the sum or the minimum of interelement distances amongst a subset chosen from a given set. The problems arise in a variety of contexts including the location of obnoxious facilities, the selection of diverse groups, and the identification of dense subgraphs. They are known to be computationally difficult. In this paper, we propose a Lagrangian approach toward their solution and report the results of an extensive computational experimentation. Our results show that our Lagrangian approach is reasonably fast, that it yields heuristic solutions which provide good lower bounds on the optimum solution values for both the sum and the minimum problems, and further that it produces decent upper bounds in the case of the sum problem. For the sum problem, the results also show that the Lagrangian heuristic compares favorably against several existing heuristics. © 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 97–114, 2000 相似文献
432.
Tjallie A. M. Scheltinga Sebastiaan J. H. Rietjens Sirp J. De Boer Celeste P. M. Wilderom 《Low Intensity Conflict & Law Enforcement》2005,13(1):54-69
In peace-support operations, employees of international humanitarian organisations often clash with those of the military. A lack of familiarity with each other's practices and values, embedded in their respective organisational cultures, is often seen as the culprit. This article presents and illustrates a road map to manage such cultural differences between cooperating organisations. We found that the military culture, in our Bosnian case study, was seen to operate as a hierarchical culture (characterised by formalisation, stability, predictability and efficiency). The culture of international humanitarian organisations, on the other hand, was depicted as clan-type (characterised by teamwork, participation and consensus). To facilitate the creation of cultural awareness as well as respect for, and reconciliation of, cultural differences we recommend several concrete actions that could improve civil-military cooperation. 相似文献
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This article discusses the behavior of three continuous sampling plans: continuous sampling plan 1 (CSP 1) and continuous sampling plan 2 (CSP 2) developed by Dodge [5] and Dodge and Torrey [7], and multilevel continuous sampling plan 2 (MLP 2) developed by Lieberman and Solomon [11], when the quality of successive units in a continuous production process follows a two-state time-homogeneous Markov chain. We first derive the average outgoing quality (AOQ) expressions of these plans. Exact procedures for determining the average outgoing quality limit (AOQL) can be obtained only for CSP 1. For CSP 2 and MLP 2 plans, iterative procedures have been used to obtain the AOQL contours. For these plans, it is assumed that the serial correlation coefficient between the two consecutive random variables of the Markov chain is known. In addition, estimation procedures for the coefficient are given. We show that if the serial correlation coefficient of the Markov chain is positive (negative), the AOQL is increased (decreased) as compared to the case when the successive units in the production process follows a Bernoulli pattern. Let r denote the number of production units examined in succession which are found to be of good quality and k denote the inverse of the sampling fraction employed when quality is good. Then if r and k are sufficiently small, it is observed from the graph that, for small departures of the serial correlation coefficient from zero, the AOQL values do not differ significantly for each of the three plans; whereas for sufficiently large values of r and k, the AOQL values differ significantly. Various aspects of these plans, such as their operating characteristics 2 (OC 2) and the serial correlation coefficient, are discussed. 相似文献
435.
The structural changes inside the French innovation system have impacted the role of defense firms since the late 1980s. Major changes have affected the defense budget and public R&D funding system in particular. The aim of this article is to understand French defense firms’ repositioning within the National Innovation System (NIS) based on an analysis of their R&D behavior over a long period of time (1987–2010). We show that French defense firms remain major players in the NIS and faced up to these major changes by adapting the funding of their R&D and their research priorities and rolling out new innovation capabilities. Additionally, they developed new innovation models to take advantage of new collaborative partnerships developed for civil and military markets. 相似文献
436.
What explains the pace at which militaries adopt new technology? We argue that the hierarchical structure and unique expertise requirements of military organizations combine to empower select individuals as ‘gatekeepers’ of innovation. These individuals acquire beliefs throughout their military careers regarding the nature and means of warfare that act to shape their attitudes towards new military innovations. By filtering, sidelining, and ignoring competing sources of advice and information, these officers actively inhibit the adoption of new, often advantageous, innovations. We develop this argument through the analysis of two cases: the delayed acquisition of breech-loading and repeating rifles by the Union Army during the American Civil War, and the failure of the US Army to adopt an adequate heavy-type tank in World War II. 相似文献
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Adam M. Scheinman 《The Nonproliferation Review》2013,20(2):257-267
International Atomic Energy Agency (IAEA) safeguards are under more stress today than at any time in their history. Compliance concerns, a shortage of resources and technology, and growing responsibilities threaten to undermine the effectiveness and credibility of this vital and fundamental pillar of the nonproliferation regime. To address this challenge, the United States recently launched the Next Generation Safeguards Initiative. The goal of this initiative is to ensure the IAEA makes the fullest possible use of its existing authority to prevent the diversion of safeguarded material and to investigate suspicious activities. The initiative will advance state-of-the-art technology, foster the development of a new generation of safeguards experts, and promote technology collaborations and safeguards-conscious infrastructure in states using or pursuing nuclear power. Although it has a domestic focus, the initiative's intent is to catalyze a much broader commitment to international safeguards in partnership with other governments and the IAEA. 相似文献