Exploring dynamic fan shapes for nearby traffic monitoring queries in road networks

In this paper, we first introduce the traffic status estimation service, a location-based continuous range query application provided by the CarWeb system. The service provides users nearby realtime traffic estimation according to their locations and moving behaviors. This paper focuses on how to provide users with the most relevant information efficiently and accurately. We propose the Continuous Query with Dynamic Fan-Shape framework ( CQ-DFS ) which dynamically changes parameters of fan shape range query to efficiently acquire more useful query results without compromising the performance of the system. We conduct extensive experiments to demonstrate the effectiveness of CQ-DFS framework by using real world vehicle trajectories.