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391.
In this note we describe a local-search heuristic (LSH) for large non-unicost set-covering problems (SCPs). The new heuristic is based on the simulated annealing algorithm and uses an improvement routine designed to provide low-cost solutions within a reasonable amount of CPU time. The solution costs associated with the LSH compared very favorably to the best previously published solution costs for 20 large SCPs taken from the literature. In particular, the LSH yielded new benchmark solutions for 17 of the 20 test problems. We also report that, for SCPs where column cost is correlated with column coverage, the new heuristic provides solution costs competitive with previously published results for comparable problems. © 1995 John Wiley & Sons, Inc.  相似文献   
392.
This article defines and develops a simulation optimization system based upon response surface classification and the integration of multiple search strategies. Response surfaces are classified according to characteristics that indicate which search technique will be most successful. Typical surface characteristics include statistical measures and topological features, while search techniques encompass response surface methodology, simulated annealing, random search, etc. The classify-then-search process flow and a knowledge-based architecture are developed and then demonstrated with a detailed computer example. The system is useful not only as an approach to optimizing simulations, but also as a means for integrating search techniques and thereby providing the user with the most promising path toward an optimal solution. © 1995 John Wiley & Sons, Inc.  相似文献   
393.
军工产品质量与可靠性信息管理运行机制的探讨   总被引:1,自引:0,他引:1  
本文在总结我国多年开展质量与可靠性信息管理工作经验的基础上,根据信息管理的任务和应遵循的原则,对建立具有我国特色的军工产品质量与可靠性信息管理运行机制的问题进行了探讨。提出了为全面保证军工产品质量与可靠性信息系统能持续、有效地运行,所应建立的运行机制。  相似文献   
394.
Nonlinear initial alignment is a significant research topic for strapdown inertial navigation system(SINS).Cubature Kalman filter(CKF)is a popular tool for nonlinear initial alignment.Standard CKF assumes that the statics of the observation noise are pre-given before the filtering process.Therefore,any unpredicted outliers in observation noise will decrease the stability of the filter.In view of this problem,improved CKF method with robustness is proposed.Multiple fading factors are introduced to rescale the obser-vation noise covariance.Then the update stage of the filter can be autonomously tuned,and if there are outliers exist in the observations,the update should be less weighted.Under the Gaussian assumption of KF,the Mahalanobis distance of the innovation vector is supposed to be Chi-square distributed.Therefore a judging index based on Chi-square test is designed to detect the noise outliers,determining whether the fading tune are required.The proposed method is applied in the nonlinear alignment of SINS,and vehicle experiment proves the effective of the proposed method.  相似文献   
395.
396.
为解决部队的日常训练,设计了双三七自行高炮火控系统操作模拟器.由于其火控系统规模大,系统的多数功能是通过面板上繁多的开关、旋钮实现的,这为系统的仿真带来极大困难.本文介绍了通过综合利用数字仿真、数字检测、数字控制等技术,完成该系统仿真的设计.  相似文献   
397.
型号设计阶段是装备质量形成的源头,质量评价是保证型号研制方案质量的重要手段。根据型号研制阶段设计质量评价新需求,应用现代产品质量理论及方法,阐述了型号设计质量评价的概念、特点、过程、方法体系及软件工具系统,为保证装备方案质量提供切实可行的技术途径,使装备质量持续改进成为可能。  相似文献   
398.
    
Traditional inventory systems treat all demands of a given item equally. This approach is optimal if the penalty costs of all customers are the same, but it is not optimal if the penalty costs are different for different customer classes. Then, demands of customers with high penalty costs must be filled before demands of customers with low penalty costs. A commonly used inventory policy for dealing with demands with different penalty costs is the critical level inventory policy. Under this policy demands with low penalty costs are filled as long as inventory is above a certain critical level. If the inventory reaches the critical level, only demands with high penalty costs are filled and demands with low penalty costs are backordered. In this article, we consider a critical level policy for a periodic review inventory system with two demand classes. Because traditional approaches cannot be used to find the optimal parameters of the policy, we use a multidimensional Markov chain to model the inventory system. We use a sample path approach to prove several properties of this inventory system. Although the cost function is not convex, we can build on these properties to develop an optimization approach that finds the optimal solution. We also present some numerical results. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008  相似文献   
399.
In this article an algorithm for computing upper and lower ? approximations of a (implicitly or explicitly) given convex function h defined on an interval of length T is developed. The approximations can be obtained under weak assumptions on h (in particular, no differentiability), and the error decreases quadratically with the number of iterations. To reach an absolute accuracy of ? the number of iterations is bounded by

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400.
本文基于舰艇柴油机的推进工况,研究通过测试一组稳态参数,建立物理和数学模型,获取缸内示功图。分析认为:该方法简单实用、成本低,与实测示功图比较误差小,完全满足使用管理中性能分析、工况评判、故障诊断等方面的需要,是解决舰艇柴油机实测示功图困难的一种新的尝试。  相似文献   
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