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421.
本文根据登月舱的运动方程,在固定推力条件下,给出最优推力方向。在最优推力方向上对摄动方程加入自适应调节控制,得到状态跟踪的稳定性,使受控系统的输出跟踪状态精度得到保证。 相似文献
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We introduce an optimal stopping problem for selling an asset when the fixed but unknown distribution of successive offers is from one of n possible distributions. The initial probabilities as to which is the true distribution are given and updated in a Bayesian manner as the successive offers are observed. After receiving an offer, the seller has to decide whether to accept the offer or continue to observe the next offer. Each time an offer is observed a fixed cost is incurred. We consider both the cases where recalling a past offer is allowed and where it is not allowed. For each case, a dynamic programming model and some heuristic policies are presented. Using simulation, the performances of the heuristic methods are evaluated and upper bounds on the optimal expected return are obtained. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013 相似文献
424.
Christos Kassimeris 《Small Wars & Insurgencies》2013,24(2):256-273
The contemporary history of three countries was marked on July 1974 when the Greek colonels overthrew the legitimate government of Cyprus, Turkey invaded the island to preserve her interests and Greece returned to democracy, but withdrew from NATO. The apathy of her allies was a bitter experience for Greece, considering that the government in Athens was struggling to cope with the consequences of the invasion and Turkey's aggression, as well as with the diplomatic isolation caused by the seven-year dictatorial rule. This paper examines the response of the Greek government and makes particular reference to Karamanlis's archives and Greek parliamentary proceedings. The purpose of the present study is to explore whether Greece was genuinely committed to the settlement of the Cyprus issue and failed due to lack of support or simply ignored the appeals of the Cypriot people and pursued more vital foreign policy objectives, thus contributing to the partition of the island. 相似文献
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Rhys Ball 《Small Wars & Insurgencies》2013,24(1):119-141
In 1955, the New Zealand government authorised the creation of a Special Forces unit to operate with British forces in Malaya to counter a communist-inspired guerrilla insurgency. Drawing upon the operational experiences of the New Zealand SAS largely taken from the Cold War period, and underpinned by Colin Gray's Special Forces essentials of ‘economy of force’ and ‘expansion of choice’, this article will show how New Zealand's SAS is now accepted not only as a respected and relevant part of the nation's military capability, but also empowers its political decision-makers with the confidence to take on significant, and at times difficult, strategic foreign-policy choices. 相似文献
426.
研究Gauss伪谱法在空空导弹最优中制导律设计中的应用。建立空空导弹中制导律设计问题最优控制模型,首次提出采用Gauss伪谱法求解最优中制导律设计问题的思路,详细阐述了求解流程,通过仿真算例验证了求解方法的有效性,并同比例导引、打靶法等传统方法进行了对比。仿真结果表明,综合考虑性能指标、计算精度、计算效率等因素,Gauss伪谱法具有明显优势,Gauss伪谱法求解结果和求解效率与配点个数密切相关。研究结果为空空导弹中制导律设计提供理论参考。 相似文献
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Eszter Simon 《Small Wars & Insurgencies》2013,24(6):886-911
This article investigates the cognitive limitations on policy change in counterinsurgency (COIN) efforts by examining why American decision-makers failed to revise their government strategy substantially while fighting the insurgency in Afghanistan in 2003–2014 and why their British counterparts were more successful in adjusting their policies in the Malayan insurgency in 1948–1954. Unlike most of the COIN literature that concentrates on military strategy and tactics, the analysis of government policy-making in Malaya holds some important political lessons for American leaders today despite differences between the insurgencies in Afghanistan and British Malaya. As a response to the criticism of COIN studies in general that they lack theoretical guidance, this article utilizes an integrated cognitivist-prospect theory framework. It is argued that some of the COIN literature mistakenly suggests that a more difficult strategic situation was primarily responsible for American failure in Afghanistan. Instead, American decision-makers faced a more difficult task cognitively than their British counterparts, as policy change in Afghanistan would have required greater ideational change. American principals were much more attached to their beliefs emotionally, had no alternative problem representation, and had to shift between frames in order to engineer a response that was more in line with events on the ground in Afghanistan. Regarding prospect theory, findings indicate that gains frames appear to be unhelpful in monitoring progress until catastrophic failure endangers the reference point, and that decision-makers often have more than one reference point to attune their policies to, which often results in suboptimal choices with regard to at least one reference point. 相似文献
428.
根据舰艇防空武器拦截过程的时间连续性和拦截效果的不确定性特点,提出了智能规划和优化调度相结合的舰艇防空计划生成方法。在规划阶段,先用智能规划描述语言PDDL对舰艇防空问题进行建模;针对新的来袭目标或观察的拦截结果,利用智能规划的高效行动推理能力,快速生成可能的备选行动方案;在优化调度阶段,对已生成的备选方案的行动系列进行时间、资源冲突处理,并计算选择出当前最佳拦截方案。与现有的采用离散化处理的武器-目标分配方法相比,该规划与调度过程充分体现了拦截过程的连续性,拦截效果的不确定性,拦截过程中的武器协同,以及最佳拦截时机的选择等,更好地描述了舰艇防空的实际过程。最后,通过蒙特卡罗仿真试验,验证了算法的有效性,为舰艇的自动化防空提供了一种新的解决办法。 相似文献
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