排序方式: 共有69条查询结果,搜索用时 171 毫秒
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分析了备件库存管理所对应的库存控制策略及其有关的因素,以费用为目标函数、不缺备件概率为约束条件,运用概率论及库存论原理建立了备件库存限量的决策摸型。 相似文献
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利用平面自治系统的极限环理论和分支理论研究了一类无穷次多项式系统,并讨论了该系统极限环的存在性和唯一性。应用所得结论,推广并改进了前人的结果。 相似文献
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We study joint preventive maintenance (PM) and production policies for an unreliable production‐inventory system in which maintenance/repair times are non‐negligible and stochastic. A joint policy decides (a) whether or not to perform PM and (b) if PM is not performed, then how much to produce. We consider a discrete‐time system, formulating the problem as a Markov decision process (MDP) model. The focus of the work is on the structural properties of optimal joint policies, given the system state comprised of the system's age and the inventory level. Although our analysis indicates that the structure of optimal joint policies is very complex in general, we are able to characterize several properties regarding PM and production, including optimal production/maintenance actions under backlogging and high inventory levels, and conditions under which the PM portion of the joint policy has a control‐limit structure. In further special cases, such as when PM set‐up costs are negligible compared to PM times, we are able to establish some additional structural properties. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005. 相似文献
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研究一类描述多分子化学反应的数学模型应用微分方程定性理论,完整地解决了该系统极限环的存在性、不存在性和唯一性问题。 相似文献
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Whipple shield, a dual-wall system, as well as its improved structures, is widely applied to defend the hypervelocity impact of space debris (projectile). This paper reviews the studies about the mechanism and process of protection against hypervelocity impacts using Whipple shield. Ground-based experiment and numerical simulation for hypervelocity impact and protection are introduced briefly. Three steps of the Whipple shield protection are discussed in order, including the interaction between the projectile and bumper, the movement and diffusion of the debris cloud, and the interaction between the debris cloud and rear plate. Potential improvements of the protection performance focusing on these three steps are presented. Representative works in the last decade are mentioned specifically. Some prospects and suggestions for future studies are put forward. 相似文献
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本文分析影响被炸药驱动下抛板极限速度的重要因素,讨论了一些经验公式的适用范围;提出了根据二维抛板的数值计算得到的两个重要规律:①在炸药与抛板的质量比相同的情况下,抛板的极限速度之间具有一定的相似关系;②修正的古尼公式可用来计算二维抛板的极限速度。 相似文献
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用多尺度法求出了系统的一次近似平均方程和极坐标形成的分叉响应方程。研究了系统非共振情况下的平衡点性质和Hopf分叉,讨论了零解和极限环的稳定性 相似文献
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破损潜艇应急起浮操纵控制研究 总被引:3,自引:1,他引:2
在建立高压气应急吹除模型的基础上,通过计算机模拟仿真对高压气吹除过程中计算型潜艇应急上浮的主要参数进行计算和分析,给出了艏部破损和舯部破损时操纵安全界限图中的进水限制线,提高了潜艇应急上浮操纵的安全性. 相似文献