| Popis: |
To increase directional query efficiency, based on the study of existing algorithms of directional query, new pruning rules for directional query were given, combined with the new index structure MB-tree. The rules exclude the MBRs outside the query area and output all leaf nodes in the MBRs inside the query area. Based on the orders defined in MB-tree, a new algorithm of directional query is given combining with MB-tree by using recursive method, and the new algorithm can reduce I/O cost effectively. Experiment showed that the new directional query algorithm reduces the number of visited nodes, decreases I/O cost, and improves the efficiency of directional query. |
