Preference-aware publish/subscribe delivery with diversity

Abstract

In publish/subscribe systems, users describe their interests via subscriptions and are notified whenever new interesting events become available. Typically, in such systems, all subscriptions are considered equally important. However, due to the abundance of information, users may receive overwhelming amounts of events. In this paper, we propose using a ranking mechanism based on user preferences, so that only top-ranked events are delivered to each user. Since many times top-ranked events are similar to each other, we also propose increasing the diversity of delivered events. Furthermore, we examine a number of different delivering policies for forwarding ranked events to users, namely a periodic, a sliding-window and a history-based one. We have fully implemented our approach in SIENA, a popular publish/subscribe middleware system, and report experimental results of its deployment.