Quality-Aware Probing of Uncertain Data with Resource Constraints

  • Authors:
  • Jinchuan Chen;Reynold Cheng

  • Affiliations:
  • Department of Computing, Hong Kong Polytechnic University, Hong Kong,;Department of Computing, Hong Kong Polytechnic University, Hong Kong,

  • Venue:
  • SSDBM '08 Proceedings of the 20th international conference on Scientific and Statistical Database Management
  • Year:
  • 2008

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Abstract

In applications like sensor network monitoring and location-based services, due to limited network bandwidth and battery power, a system cannot always acquire accurate and fresh data from the external environment. To capture data errors in these environments, recent researches have proposed to model uncertainty as a probability distribution function (pdf), as well as the notion of probabilistic queries, which provide statistical guarantees on answer correctness. In this paper, we present an entropy-based metric to quantify the degree of ambiguity of probabilistic query answers due to data uncertainty. Based on this metric, we develop a new method to improve the query answer quality. The main idea of this method is to acquire (or probe) data from a selected set of sensing devices, in order to reduce data uncertainty and improve the quality of a query answer. Given that a query is assigned a limited number of probing resources, we investigate how the quality of a query answer can attain an optimal improvement. To improve the efficiency of our solution, we further present heuristics which achieve near-to-optimal quality improvement. We generalize our solution to handle multiple queries. An experimental simulation over a realistic dataset is performed to validate our approaches.