Preference and Diversity-based Ranking in Network-Centric Information Management Systems


A great amount of information becomes available to users every day through a number of on-line sources. However, locating valuable or important information can prove out to be an overwhelming task, due to the great volume of accessible data. Therefore, in addition to traditional web search methods, proactive search models are becoming increasingly popular and used by a continuously growing portion of Internet users. In these models, users specify their interests via subscriptions and the system automatically forwards all new information (or events) that matches their subscriptions to them. One type of such proactive systems are publish/subscribe systems (e.g. news alerts, rss feeds, social networks). The main feature of publish/subscribe systems is the generation of information from every individual user and the need for its immediate forwarding towards all other interested users. For this reason, we face the challenge of handling very large, continuous flows of information, a fact that demands the ranking of the forwarded information, so that users receive only what is most useful to them.

This project concerns the development, implementation and evaluation of models, algorithms and techniques for supporting the ranking of information being forwarded towards the users of large-scale network-centric information management systems, such as publish/subscribe systems. Ranking is based on the importance of each piece of information. We consider that importance is influenced by two main factors: (i) relevance to user interests and (ii) diversity. Relevance is important so that users are only notified about the most interesting events according to their specified subscriptions, while diversity ensures that the received notifications are not referring to the same or similar events.

Our paper below surveys related literature in the field of result diversification:

This research has been co-financed by the European Union (European Social Fund - ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) - Research Funding Program: Heracleitus II. Investing in knowledge society through the European Social Fund.
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