“…In the pushbased model [4,5], XML streams are broadcasted to multiple clients, which must evaluate continuous, sophisticated queries (as opposed to simple, single path specifications) with limited memory capacity and processing power. In the pullbased model [6][7][8][9][10], such as publish-subscribe or event notification systems, XML streams are disseminated to subscribers, but a larger number of registered queries pose heavy workload on the server. Hence, expediting multiple queries on XML streams is the core technical challenge.…”