Indexing moving objects: A real time approach1

Indexing moving objects usually involves a great amount of updates, caused by objects reporting their current position. In order to keep the present and past positions of the objects in secondary memory, each update introduces an I/O and this process is sometimes creating a bottleneck. In this paper we deal with the problem of minimizing the number of I/Os in such a way that queries concerning the present and past positions of the objects can be answered efficiently. In particular we propose two new approaches that achieve an asymptotically optimal number of I/Os for performing the necessary updates. The approaches are based on the assumption that the primary memory suffices for storing the current positions of the objects.