An efficient processing of range spatial keyword queries over moving objects

In this paper, we propose an efficient method of processing range spatial keyword queries. In particular, we focus on minimizing (i) the computation cost at the server and (ii) the communication cost between moving objects and the server. As the moving objects dynamically change their location, they should contact the server. This, however, increases the communication cost as well as the server computation cost, as the number of moving objects is increased. In the traditional researches, the concept of safe region is used. A safe region assigned to each moving object o is an area such that o cannot affect the results of the queries as long as it is moving within this area. However, the construction cost of the safe region can become a burden to the server. Therefore, we introduce pruning rules to decrease the overhead of constructing the safe region. In addition, the proposed algorithm for processing continuous range spatial keyword queries over moving objects utilizes a new spatial index structure, called the partition retrieved list, to help the system quickly construct the safe region of each object. Through experimental evaluations, we verify the effectiveness of our proposed algorithm.