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Targeted killings have become a central tactic in the United States' campaigns against militant and terrorist groups in the Middle East, Asia, and Africa. Both ‘demand’ and ‘supply’ factors explain the rise of targeted killings. Demand for targeted killings increased as the United States faced new threats from militant groups that could not be effectively countered with conventional military force. Concerns about the political consequences of long-term military involvement overseas and American casualties led political leaders to supply more targeted killings. The conclusion discusses how this tactic may have unintended consequences as other states follow the United States use of targeted killings.  相似文献   
64.
We examine the setup and improvement policies for a production process with multiple performance states. Assume that the production process deteriorates randomly over time, following a Markovian process with known transition probabilities. In order to reduce the production cost incurred because of process deterioration, the process is inspected at the end of each period. Then one of three actions may be taken: do nothing, perform routine process setup, or perform routine setup and process improvement. The routine setup operation returns the process to its best performance state, whereas the process improvement action may reduce future production and setup costs and improve the process-state transition probabilities. A discounted Markovian model is formulated to find the strategy that minimizes the total cost of operating the production process. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44: 383–400, 1997  相似文献   
65.
The authors study a discrete-time, infinite-horizon, dynamic programming model for the replacement of components in a binary k-out-of-n failure system. (The system fails when k or more of its n components fail.) Costs are incurred when the system fails and when failed components are replaced. The objective is to minimize the long-run expected average undiscounted cost per period. A companion article develops a branch-and-bound algorithm for computing optimal policies. Extensive computational experiments find it effective for k to be small or near n; however, difficulties are encountered when n ≥ 30 and 10 ≤ kn − 4. This article presents a simple, intuitive heuristic rule for determining a replacement policy whose memory storage and computation time requirements are O(n − k) and O(n(n − k) + k), respectively. This heuristic is based on a plausible formula for ranking components in order of their usefulness. The authors provide sufficient conditions for it to be optimal and undertake computational experiments that suggest that it handles parallel systems (k = n) effectively and, further, that its effectiveness increases as k moves away from n. In our test problems, the mean relative errors are under 5% when n ≤ 100 and under 2% when kn − 3 and n ≤ 50. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44, 273–286, 1997.  相似文献   
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Glossary     
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67.
The years following the signature of the Nuclear Non-Proliferation Treaty (NPT) of 1968 have generally been seen as a period of neglect in US non-proliferation policy. While joining recent scholarship questioning this, the article also shows that the policies that emerged from the Nixon–Ford years were the product of a broad range of factors that constrained both the United States’ ability and willingness to build an effective non-proliferation regime. These included the Nixon administration’s initial skepticism regarding the NPT, as well as the global dispersion of power away from the US, combined with the continued importance of anti-Soviet containment.  相似文献   
68.
Within the framework of classical theory, the joint US Army-Marine field manual Counterinsurgency (FM 3-24) described an ambitious set of skills required for success against guerrillas. But if counterinsurgency, as FM 3-24 describes it, is ‘the graduate level of warfare’, then these two military services have been for years systematically failing to train their talent in the appropriate fields. In today's small wars, NCOs serve as modern-day Mounties, and consequently require at least a modest undergraduate education in armed good governance.  相似文献   
69.
Why should deployment affect re‐enlistment? In our model, members enter the military with naïve beliefs about deployment and use actual deployment experience to update their beliefs and revise their expected utility of re‐enlisting. Empirically, re‐enlistment is related to the type and number of deployments, consistent with the learning model. Non‐hostile deployment increases first‐term re‐enlistment but hostile deployment has little effect except for the Army, where the effect is positive. Both types increase second‐term re‐enlistment. Interestingly, first‐term members with dependants tend to respond to deployment like second‐term members. In addition, deployment acts directly to affect re‐enlistment, not indirectly through time to promotion.  相似文献   
70.
Export controls and international safeguards are central to ensuring international confidence in the peaceful uses of nuclear materials and technologies and to achieving adequate oversight on the transfer and use of nuclear materials, technology, and equipment required for the development of proliferation-sensitive parts of the nuclear fuel cycle. Although the independent strengths of export controls and international safeguards rely largely on universal adherence, there may be opportunities to exploit the shared strengths of these systems. This article provides background information on the separate evolution of export controls and international safeguards, considers how these two elements of the nonproliferation regime interact, and identifies some possible avenues that could, over time, lead to wholly integrated activities.  相似文献   
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