Asking generalized queries to ambiguous oracle

  • Authors:
  • Jun Du;Charles X. Ling

  • Affiliations:
  • Department of Computer Science, The University of Western Ontario, London, Ontario, Canada;Department of Computer Science, The University of Western Ontario, London, Ontario, Canada

  • Venue:
  • ECML PKDD'10 Proceedings of the 2010 European conference on Machine learning and knowledge discovery in databases: Part I
  • Year:
  • 2010

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Abstract

Asking generalized queries (by regarding some features as don't-care) in active learning has been proposed and studied recently. As each generalized query is equivalent to a set of specific ones, the answers from the oracle can usually provide more information thus speeding up the learning effectively. However, as the answers to the generalized queries might be uncertain, previous studies often assume that the oracle is capable of providing (accurate) probabilistic answers. This assumption, however, is often too stringent in real-world situations. In this paper, we make a more realistic assumption that the oracle can only provide (non-probabilistic) ambiguous answers, similar to the setting in multiple-instance learning. That is, the generalized query is labeled positive if at least one of the corresponding specific queries is positive, and is labeled negative otherwise. We therefore propose an algorithm to construct the generalized queries and improve the learning model with such ambiguous answers in active learning. Empirical study shows that, the proposed algorithm can significantly speed up the learning process, and outperform active learning with either specific queries or inaccurately answered generalized queries.