Implementation and evaluation of an adaptive neighborhood information retrieval system for mobile users

Rapid development and ongoing research activities on mobile devices, digital cartography, and global positioning systems (GPSs) have brought us a new type of software service - location-based services for moving objects (such as people with mobile devices and vehicles with car navigation systems). Realization of location-based services requires new technologies to provide appropriate neighborhood information to moving objects. A general approach to providing neighborhood information to moving objects is to retrieve objects in the neighborhood of a moving object with a spatial query that uses the traditional Euclidean distance. However, if we know the destination and the estimated route of a moving object, we would be able to provide more appropriate information to the object. Based on this idea, we have developed adaptive spatial query generation models that take the trajectory of a moving object into consideration to retrieve desired information. In this paper, we describe the design and implementation of the neighborhood information retrieval system based on the models and evaluate its effectiveness with experiments.