Exact processing of uncertain top-k queries in multi-criteria settings

Abstract

Traditional rank-aware processing assumes a dataset that contains available options to cover a specific need (e.g., restaurants, hotels, etc) and users who browse that dataset via top- k queries with linear scoring functions, i.e., by ranking the options according to the weighted sum of their attributes, for a set of given weights. In practice, however, user preferences (weights) may only be estimated with bounded accuracy, or may be inherently uncertain due to the inability of a human user to specify exact weight values with absolute accuracy. Motivated by this, we introduce the uncertain top-k query ( UTK ). Given uncertain preferences, that is, an approximate description of the weight values, the UTK query reports all options that may belong to the top- k set. A second version of the problem additionally reports the exact top- k set for each of the possible weight settings. We develop a scalable processing framework for both UTK versions, and demonstrate its efficiency using standard benchmark datasets.