Dynamic range query in spatial network environments

Moving range queries over mobile objects are important in many location management applications. There have been quite a few research works in this area. However, all existing solutions assume an open space environment, which are either not applicable to spatial network environment or require nontrivial extensions. In this paper, we consider a new class of query called Dynamic Range Query. A dynamic range query is a moving range query in a network environment, which retrieves the moving objects within a specified network distance of the moving query point. As this query point moves in the network, the footprint (or shape) of the query range changes accordingly to reflect the new relevant query area. Our execution strategy leverages computing power of the moving objects to reduce server load and communication costs. This scheme is particularly desirable for many practical applications such as vehicles in a street environment, where mobile energy is not an issue. We describe the design details and present our simulation study. The performance results indicate that our solution is almost two magnitudes better than a query index method in terms of server load, and requires similar number of messages when compared to a query-blind optimal scheme.