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An efficient spatial publish/subscribe system for intelligent location-based services

The advance in wireless Internet and mobile computing brought the booming of intelligent Location-Based Services(LBS), which can actively push location-dependent information to mobile users according to their predefined interest. The successful development of push-based LBS applications relies on the existence of a publish/subscribe middleware that can handle spatial relationship. This paper presents an efficient spatial publish/subscribe system that can serve as the middleware for intelligent LBS applications. The basic models, including spatial event model, spatial subscription model and notification model, are introduced and the over-all architecture is presented. Two kinds of spatial predicate that can meet most common requirement of intelligent location aware applications are also discussed. Furthermore, we propose a novel spatial event processing approach that dispatches the spatial subscriptions to self-positioning mobile devices. By leveraging client-side computing resource and decreasing the communication times, the server-side workload is relieved and the communication cost is reduced. Experimental results clearly demonstrate the efficiency of our approach.