Querying moving events in wireless sensor networks

The detection and tracking of composite events in Wireless Sensor Networks often employ ad-hoc solutions that aim at detecting and tracking only specific types of events or use generic query languages that are not specifically built to manage events. We propose a new query language and an in-network query processing solution that enable the definition of queries to track and gather information from events, using wireless sensor networks. The proposed language provides clauses aimed at defining dynamic tracking tasks and the autonomous migration of the queries on the network, depending on the event mobility. We describe the query model and the language, discuss its implementation, and present the results of the comparison with a TinyDB-like approach. We show that our approach is scalable with event mobility and that it is more energy efficient than TinyDB-like approaches.