Continuous Reverse Nearest Neighbor Search

The query service for the location of an object is called Location Based Services (LBSs), and Reverse Nearest Neighbor (RNN) queries are one of them. RNN queries have diversified applications, such as decision support system, market decision, query of database document, and biological information. Studies of RNN in the past, however, focused on inquirers in immobile status without consideration of continuous demand for RNN queries in moving conditions. In the environment of wireless network, users often remain in moving conditions, and sending a query command while moving is a natural behavior. Availability of such service therefore becomes very important; we refer to this type of issue as Continuous Reverse Nearest Neighbor (CRNN) queries. Because an inquirer’s location changes according to time, RNN queries will return different results according to different locations. For a CRNN query, executing RNN search for every point of time during a continuous query period will require a tremendously large price to pay. In this work, an efficient algorithm is designed to provide precise results of a CRNN query in just one execution. In addition, a large amount of experiments were conducted to verify the above-mentioned method, of which results of the experiments showed significant enhancement in efficiency.