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321.
Scholars and policymakers argue that violent actors – termed ‘spoilers’ – pose a significant threat to civil war peace agreements. Yet existing research, which is overly reliant on single-case studies, has not effectively determined how prevalent spoiling is, or thoroughly examined what its ultimate effects are on peace agreements. This article draws on a newly constructed cross-national dataset of spoiling following 241 civil war peace agreements in the post-Cold War era to analyze spoiling. It finds that spoiling intended to terminate an agreement is not as common as typically assumed, but still plagues a sizeable number of peace agreements. Moreover, most actors who resort to this strategy typically fail in their goals and the agreement is not at risk, despite the high publicity and attention given to these threats. Yet particular types of actors, most notably paramilitaries and state security forces excluded from the agreement, can pose a significant threat to peace.  相似文献   
322.
    
We study a service design problem in diagnostic service centers, call centers that provide medical advice to patients over the phone about what the appropriate course of action is, based on the caller's symptoms. Due to the tension between increased diagnostic accuracy and the increase in waiting times more in‐depth service requires, managers face a difficult decision in determining the optimal service depth to guide the diagnostic process. The specific problem we consider models the situation when the capacity (staffing level) at the center is fixed, and when the callers have both congestion‐ and noncongestion‐related costs relating to their call. We develop a queueing model incorporating these features and find that the optimal service depth can take one of two different structures, depending on factors such as the nurses' skill level and the maximum potential demand. Sensitivity analyses of the two optimal structures show that they are quite different. In some situations, it may (or may not) be optimal for the manager to try to expand the demand at the center, and increasing skill level may (or may not) increase congestion. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012  相似文献   
323.
    
We develop models that lend insight into how to design systems that enjoy economies of scale in their operating costs, when those systems will subsequently face disruptions from accidents, acts of nature, or an intentional attack from a well‐informed attacker. The systems are modeled as parallel M/M/1 queues, and the key question is how to allocate service capacity among the queues to make the system resilient to worst‐case disruptions. We formulate this problem as a three‐level sequential game of perfect information between a defender and a hypothetical attacker. The optimal allocation of service capacity to queues depends on the type of attack one is facing. We distinguish between deterministic incremental attacks, where some, but not all, of the capacity of each attacked queue is knocked out, and zero‐one random‐outcome (ZORO) attacks, where the outcome is random and either all capacity at an attacked queue is knocked out or none is. There are differences in the way one should design systems in the face of incremental or ZORO attacks. For incremental attacks it is best to concentrate capacity. For ZORO attacks the optimal allocation is more complex, typically, but not always, involving spreading the service capacity out somewhat among the servers. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011  相似文献   
324.
This article presents a regional overview of US‐Latin American security relations, focusing on those countries where US national security interests are most likely to be endangered over the next two decades. The author examines the current US strategy of ‘shaping’ the Latin security environment, with a view to assessing the strength and weaknesses of this approach. The article presents some policy recommendations, including the recommendation that the US do more to redress the historical imbalance in Latin American civil‐military relations by strengthening civilian institutions. It also argues that at the regional level a major effort be made to recapture momentum toward the creation of a Free Trade Association of the Americas.  相似文献   
325.
    
We study the determinants of social preferences for national defence and for police and law enforcement. For this task, we estimate a bivariate ordered probit model for a set of European countries (France, Finland, Norway, Portugal, Spain and Sweden) in 2006. Determinants of spending decisions for defence and police are found to be linked but are of significantly different magnitudes. Besides, measures against terrorist threats are positively linked to police and defence spending increases, while the subjective perception of fiscal pressure has no influence. Finally, no significant differences are found between Northern and Southern Europe.  相似文献   
326.
本文以实验结果为依据,首先分析了塑料弹体影响弹丸膛内运动的物理性能,然后结合旋转弹丸的膛内运动特征,经过模拟试验,采用数学拟合法,初步建立旋转稳定弹塑料弹体工程设计计算的数学模型(包括结构尺寸设计计算、强度计算和内弹道计算)。  相似文献   
327.
    
We study two‐agent scheduling on a single sequential and compatible batching machine in which jobs in each batch are processed sequentially and compatibility means that jobs of distinct agents can be processed in a common batch. A fixed setup time is required before each batch is started. Each agent seeks to optimize some scheduling criterion that depends on the completion times of its own jobs only. We consider several scheduling problems arising from different combinations of some regular scheduling criteria, including the maximum cost (embracing lateness and makespan as its special cases), the total completion time, and the (weighted) number of tardy jobs. Our goal is to find an optimal schedule that minimizes the objective value of one agent, subject to an upper bound on the objective value of the other agent. For each problem under consideration, we provide either a polynomial‐time or a pseudo‐polynomial‐time algorithm to solve it. We also devise a fully polynomial‐time approximation scheme when both agents’ scheduling criteria are the weighted number of tardy jobs.  相似文献   
328.
329.
ABSTRACT

China’s efforts to build a ‘new type of great power relations’ and a ‘new type of military-to-military relations’ do not constitute a major turning point in relations with the United States. Political relations set limits on military cooperation, and the two sides have been unable to construct a sustainable strategic basis for relations. This has contributed to an ‘on-again, off-again’ pattern in military ties. Trends show a pattern of frequent disruptions in military-to-military relations from 2000 to 2010, followed by an increase in interactions beginning in 2012. Nevertheless, obstacles on both sides are likely to limit mutual trust and constrain future development of military-to-military relations.  相似文献   
330.
    
On the surface of a sphere, we take as inputs two points, neither of them contained in any of a number of spherical polygon obstacles, and quickly find the shortest route connecting these two points while avoiding any obstacle. The WetRoute method presented here has been adopted by the US Navy for several applications. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 374–385, 2016  相似文献   
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