Modeling and Storing Context-Aware Preferences

Today, the overwhelming volume of information that is available to an increasingly wider spectrum of users creates the need for personalization. In this paper, we consider a database system that supports context-aware preference queries, that is, preference queries whose result depends on the context at the time of their submission. We use data cubes to store the associations between context-dependent preferences and database relations and OLAP techniques for processing contextaware queries, thus allowing the manipulation of the captured context data at different levels of abstractions. To improve query performance, we use an auxiliary data structure, called context tree, which indexes the results of previously computed preference-aware queries based on their associated context. We show how these cached results can be used to process both exact and approximate context-aware preference queries.