An RNN Queries Algorithm for Moving Objects Based on ASGI

Abstract

This paper proposes a new RNN (Reverse Nearest Neighbour) Queries algorithm for moving objects based on ASGI (Auto-Selection Grid Index). ASGI divides the space into grid cells of the same size, and each cell stores moving objects as a bucket. The RNN queries algorithm first determines the candidate objects according to the geometry characteristic of the grid and the bucket's object number, then answers the RNN queries from the candidate objects rather than all the objects. If there are too many objects within the corresponding cell of the query point, ASGI will divide the cell into grid cells again in order to decrease accessing objects. Experimental results show that the RNN queries algorithm based on ASGI outperforms traditional algorithm based on the TPR-tree.