| How an Expert can use Imperfect Knowledge to Improve an Imperfect Theory (2007) | |||||||||||||||||
Abstract | |||||||||||||||||
| This report addresses the challenge of using auxiliary information I A to improve a given theory, encoded as a belief net BE . In contrast with many other "knowledge revision" systems, we deal with the situation where this I A may be imperfect , which means BE should not necessarily incorporate that information. Instead, we provide tools to help the expert decide how to use I A . After presenting objective criteria for measuring how much I A differs from BE , we discuss ways to evaluate whether this difference is statistically significant . We then provide tools to isolate the differences --- to tell the domain expert which parts of the belief net (e.g., which links, and/or which nodes) account for the discrepancy. Two of our tools involve techniques that are of independent interest: viz., the use of a noncentral Ø 2 -test to compute the relative likelihood of two similar belief nets, and a sensitivity analysis that provides the "error-bars" around the answers returned by a belief... | |||||||||||||||||
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