Preferential publish/subscribe

In publish/subscribe systems, subscribers express their in-terests in specific events and get notified about all pub-lished events that match their interests. As the amount of information generated increases rapidly, to control the amount of data delivered to users, we propose enhancing publish/subscribe systems with a ranking mechanism, so that only the top-ranked matching events are delivered. Ran-king is based on letting users express their preferences on events by ordering the associated subscriptions. To avoid the blocking of new notifications by top-ranked old ones, we associate with each notification an expiration time. We have fully implemented our approach in SIENA, a popular publish/subscribe middleware system. 1