Determining the Minimum Scan Scope of UTop-k Queries in Uncertain Databases

The semantic of UTop-k query is based on the possible world model, and the greatest challenge in processing UTop-k queries is the explosion of possible world space. In this paper, we propose two novel algorithms, MSSUTop-k and Quick MSSUTop-k, for determining the minimum scan scope for UTop-k query processing. MSSUTop-k can achieve accurate results, but have more costly in time complexity. Oppositely, Quick MSSUTop-k achieve approximate results, and performs better in time cost. We conduct extensive experiments to evaluate the performance of our proposed algorithms, and analyze the relationship between score distribution and the minimum scan scope of UTop-k queries.