基于对象方位的连续方向查询的优化技术

The Object-Orientation-based Continuous Direction Query Optimization

连续方向查询中的结果是包含有效时域的,传统的拓扑运算无法计算出连续方向查询结果的有效时域。连续方向查询的传统处理方法是当结果发生变化时,重复执行方向查询,这种频繁的查询导致系统的消耗的增加。基于这种情况,文章提出了扩展的开放区域和相对坐标系的算法,就是先用扩展的开放区域计算出方向查询的结果,进行平移旋转,转化为相对坐标系内的坐标。

To the continuous direction query, its result is time stamp. The pological operations between open shapes and closed geometry objects do not compute time interval. In this paper we propose extended open-shapes strategy and TranslateRotate strategy, Using extended open-shapes strategy,we require the results which staisfy query condition ,and with translaterotating the results in the relative coordinates system we compute the valid time interval of result set. Finally the strategy rapidly implement the continuous query of moving object. The experiment demonstrates that extended open shape strategy performs repeated direction query strategy in I/O cost.