Ranking queries on uncertain data

Uncertain data is inherent in a few important applications such as environmental surveillance and mobile object tracking. Top-k queries (also known as ranking queries) are often natural and useful in analyzing uncertain data in those applications. In this paper, we study the problem of answering probabilistic threshold top-k queries on uncertain data, which computes uncertain records taking a probability of at least p to be in the top-k list where p is a user specified probability threshold. We present an efficient exact algorithm, a fast sampling algorithm, and a Poisson approximation based algorithm. An empirical study using real and synthetic data sets verifies the effectiveness of probabilistic threshold top-k queries and the efficiency of our methods. Categories and Subject Descriptors H.2.4 [Systems]: Query processing General Terms Algorithm, Performance, Experimentation Keywords Uncertain Data, Probabilistic Threshold Top-k Queries, Query Processing

• Type: Journal
• Year: 2011
• Where: VLDB
• Authors: Ming Hua, Jian Pei, Xuemin Lin
• Keywords: Database, Probabilistic Threshold, Threshold Top-k Queries, Uncertain Data, VLDB 2011