Expressive Location-Based Continuous Query Evaluation with Binary Decision Diagrams

This paper is concerned with developing algorithms to enable the use of a rich query language supporting spatio-temporal processing among moving objects. The queries we consider monitor location constraints. A location constraint represents a proximity relation among moving objects and among moving and static objects. Location constraint processing is like continuous query processing; once the location constraint is submitted to the system, it remains active until explicitly revoked. Location updates that represent the movement of objects are streamed into the system and trigger the evaluation of all location constraints stored with the system. Matching constraints are communicated back to interested subscribers.