基于贪心搜索的正射影像拼接方法

正射影像镶嵌是4D产品生产的重要环节,本文提出了一种基于贪心搜索正射影像拼接线搜索方法,所得的拼接线能绕开影像上投影差较大的区域,从而避免拼接缝的产生。该方法效率较高,能够适用于实际生产当中。     

顶点覆盖问题的贪心算法在网格简化中的应用研究

针对三角网格简化,设计了求解顶点覆盖问题的贪心算法,通过贪心选择最小的顶点集去＂覆盖＂边集,同时保留被简化网格的特征信息,自动实现最大程度简化。给出的实例也表明简化后的网格质量良好,算法既降低了时间复杂度又保持了原形状的特征信息。     

A new heuristic for task scheduling in heterogeneous computing environment

Heterogeneous computing （HC） environment utilizes diverse resources with different computational capabilities to solve computing-intensive applications having diverse computational requirements and constraints. The task assignment problem in HC environment can be formally defined as for a given set of tasks and machines, assigning tasks to machines to achieve the minimum makespan. In this paper we propose a new task scheduling heuristic, high standard deviation first （HSTDF）, which considers the standard deviation of the expected execution time of a task as a selection criterion. Standard deviation of the expected execution time of a task represents the amount of variation in task execution time on different machines. Our conclusion is that tasks having high standard deviation must be assigned first for scheduling. A large number of experiments were carried out to check the effectiveness of the proposed heuristic in different scenarios, and the comparison with the existing heuristics （Max-min, Sufferage, Segmented Min-average, Segmented Min-min, and Segmented Max-min） clearly reveals that the proposed heuristic outperforms all existing heuristics in terms of average makespan.     

动态规划算法和贪心算法的比较与分析

介绍了动态规划算法与贪心算法,然后通过2个经典的组合优化问题阐述了这2种算法的主要差异。     

一种求解带权集合覆盖问题的近似算法

以优化形式描述的集合覆盖问题是一个NP难问题,设计快速有效的近似算法,具有重要的理论与现实意义．基于贪心算法思想,提出了一种求解带权集合覆盖问题的近似算法,并讨论了该算法的相对近似比．