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111.
任务规划是在任务有不同威胁程度,资源消耗和战术价值条件下,寻找总战术价值最高,而又不超出约束的任务链,这对飞机完成任务中具有重要作用,针对机载资源有限、任务有不同威胁程度和战术价值,提出了基于权值编码遗传算法的任务规划方法,该算法通过对原始问题的偏离和启发式解码来得到最优的可完成任务子集.仿真结果验证了算法的有效性. 相似文献
112.
Leah Epstein 《海军后勤学研究》2009,56(8):780-786
In many applications of packing, the location of small items below large items, inside the packed boxes, is forbidden. We consider a variant of the classic online one‐dimensional bin packing, in which items allocated to each bin are packed there in the order of arrival, satisfying the condition above. This variant is called online bin packing problem with LIB (larger item in the bottom) constraints. We give an improved analysis of First Fit showing that its competitive ratio is at most , and design a lower bound of 2 on the competitive ratio of any online algorithm. In addition, we study the competitive ratio of First Fit as a function of an upper bound (where d is a positive integer) on the item sizes. Our upper bound on the competitive ratio of First Fit tends to 2 as d grows, whereas the lower bound of two holds for any value of d. Finally, we consider several natural and well known algorithms, namely, Best Fit, Worst Fit, Almost Worst Fit, and Harmonic, and show that none of them has a finite competitive ratio for the problem. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009 相似文献
113.
通过对蚁群算法的研究,用蚁群算法成功解决了无源测向定位中消除虚假点,对真实交点进行正确聚类的难题.并通过Matlab 仿真实验证明了该算法的有效性.同时该算法具有目标关联确率高、计算速度快、鲁棒性强等优点. 相似文献
114.
In hinterland container transportation the use of barges is getting more and more important. We propose a real‐life operational planning problem model from an inland terminal operating company, in which the number of containers shipped per barge is maximized and the number of terminals visited per barge is minimized. This problem is solved with an integer linear program (ILP), yielding strong cost reductions, about 20%, compared to the method used currently in practice. Besides, we develop a heuristic that solves the ILP in two stages. First, it decides for each barge which terminals to visit and second it assigns containers to the barges. This heuristic produces almost always optimal solutions and otherwise near‐optimal solutions. Moreover, the heuristic runs much faster than the ILP, especially for large‐sized instances. 相似文献
115.
This study considers the block relocation and loading problem in container terminals. The optimal loading sequence and relocation location are simultaneously decided on the basis of the desired ship‐bay and initial yard space configuration. An integer linear programming model is developed to minimize the number of relocations in the yard space on the basis of no shifts in the ship bay. The accuracy of the model is tested on small‐scale scenarios by using CPLEX. Considering the problem size in the real world, we present a rule‐based heuristic method that is combined with a mathematical model for the removal, loading, and relocation operations. The influence of rules on algorithm performance is also analyzed, and the heuristic algorithm is compared with different types of algorithms in the literature. The extensive numerical experiments show the efficiency of the proposed heuristic algorithm. 相似文献
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117.
针对传统造船模式下,车间作业计划与工艺设计串行工作方式的缺点,基于并行工程的原理,提出了分段作业计划与工艺设计的集成运行模式,为实现造船CAPP系统与PPC系统的集成化和并行化提供了实现的基础。针对集成模式的特点,建立了分段作业计划系统资源优化的数学模型,应用遗传算法解决了针对任意分段装配工艺方案的多资源平衡优化问题,可以得到每项作业最优的开工时间,同时能够给出多种资源的最优分布结果,满足了多工艺方案之间资源利用率的比较。最后,给出了计算实例,计算机模拟结果说明了这一方法的有效性。 相似文献
118.
研究辛算法应用于Hamilton系统时的Nekhoroshev稳定性,利用辛映射的插值定理,得到了辛算法的插值定理,进而把它应用到凸Hamilton系统,得到了辛算法的Nekhoroshev稳定性,即辛算法在指数长时间内的稳定性。 相似文献
119.
针对线性预测方法难以有效描述云团的非线性、非平稳变化的困难,基于经验正交函数分解(EOF)和遗传算法参数优化结合的思想,提出了一条云团非线性预测模型反演的方法途径。首先将卫星云图序列作EOF的时、空分解;在此基础上,引入遗传算法对EOF的时间系数序列进行了动力模型重构和模型参数反演,建立了EOF时间系数的非线性微分方程组;再通过时、空函数合成,构造了云团演变的动力预报模型。试验结果表明,反演的云团预报模型能较为合理地描述特定季节区域内云团演变的基本趋势,预测结果与实际云图的主要特征基本相符,尤其是实现了云图3h以上的中、长时效的客观预测。 相似文献
120.