Explanation-Based Learning (EBL)

Explanation-Based Learning (EBL)

One definition: Learning general problem-

solving techniques by observing and analyzing human solutions to specific problems.

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The EBL Hypothesis

By understanding why an example is a member of a concept, can learn the essential properties of the concept

Trade-off the need to collect many examples for the ability to "explain" single examples (a "domain" theory)

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Learning by Generalizing Explanations

Given

? Goal (e.g., some predicate calculus statement) ? Situation Description (facts) ? Domain Theory (inference rules) ? Operationality Criterion

Use problem solver to justify, using the rules, the goal in terms of the facts.

Generalize the justification as much as possible. The operationality criterion states which other terms

can appear in the generalized result.

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Standard Approach to EBL

An Explanation (detailed proof of goal) goal

facts

After Learning (go directly from facts to solution): goal

facts

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Unification-Based Generalization

? An explanation is an inter-connected collection of "pieces" of knowledge (inference rules, rewrite rules, etc.)

? These "rules" are connected using unification, as in Prolog

? The generalization task is to compute the most general unifier that allows the "knowledge pieces" to be connected together as generally as possible

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