Novel Forms of Nearest Neighbor Queries in Spatio-Temporal Applications

Several types of nearest neighbor (NN) search have been proposed and studied in the context of spatial databases. The most common type is the point NN query, which retrieves the nearest neighbors of an input point. Such a query, however, is usually meaningless in highly dynamic environments where the query point or the database objects move/change over time. In this paper we study alternative forms of nearest neighbor queries suitable for spatio-temporal applications. In particular, we first describe time-parameterized queries, where in addition to the current nearest neighbors of a query point, the result contains the expected validity period of the result (given the query and object movement), as well as the change that will occur at the end of the validity period. Then, we discuss continuous NN search where the goal is to retrieve all nearest neighbors of a query trajectory, together with the validity interval of each nearest neighbor. Νέες Μορφές Ερωτήσεων Πλησιέστερου Γείτονα σε Χωρο-χρονικές