Abstraction in belief networks: the role of intermediate states in diagnostic reasoning

  • Authors:
  • Gregory Provan

  • Affiliations:
  • Institute for Decision Systems Research, Los Altos, CA

  • Venue:
  • UAI'95 Proceedings of the Eleventh conference on Uncertainty in artificial intelligence
  • Year:
  • 1995

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Abstract

Bayesian belief networks are being increasingly used as a knowledge representation for diagnostic reasoning. One simple method for conducting diagnostic reasoning is to represent system faults and observations only. In this paper, we investigate how having intermediate nodes--nodes other than fault and observation nodes--affects the diagnostic performance of a Bayesian belief network. We conducted a series of experiments on a set of real belief networks for medical diagnosis in liver and bile disease. We compared the effects on diagnostic performance of a two-level network consisting just of disease and finding nodes with that of a network which models intermediate pathophysiological disease states as well. We provide some theoretical evidence for differences observed between the abstracted two-level network and the full network.