
Accession Number : ADA191327
Title : Generalizing the Structure of Explanations in ExplanationBased Learning.
Descriptive Note : Doctoral thesis,
Corporate Author : ILLINOIS UNIV AT URBANA COORDINATED SCIENCE LAB
Personal Author(s) : Shavlik, Jude W
PDF Url : ADA191327
Report Date : Dec 1987
Pagination or Media Count : 291
Abstract : Explanationbased learning is a recently developed approach to concept acquisition by computer. In this type of machine learning, a specific problem's solution is generalized into a form that can later be used to solve conceptually similar problems. A number of explanationbased generalization algorithms have been developed. Most do not alter the structure of the explanation of the specific problem  no additional objects nor inference rules are incorporated. Instead, these algorithms generalize by converting constants in the observed example to variables with constraints. However, many important concepts, in order to be properly learned, require that the structure of explanations be generalized. This can involve generalizing such things as the number of entities involved in a concept or the number of times some action is performed. For example, concepts such as momentum and energy conservation apply to arbitrary numbers of physical objects, clearing the top of a desk can require an arbitrary number of object relocations, and setting a table can involve an arbitrary number of guests. Two theories of extending explanations during the generalization process have been developed, and computer implementations have been created to computationally test these approaches. The Physics 101 system utilizes characteristics of mathematicallybased problem solving to extend mathematical calculations in a psychologicallyplausible way, while the BAGGER system implements a domainindependent approach to generalizing explanation structures. Both of these systems are described and the details of their algorithms presented. An approach to the operationality/generality tradeoff and an empirical analysis of explanationbased learning are also presented.
Descriptors : *LEARNING MACHINES, ACQUISITION, ALGORITHMS, COMPUTATIONS, ENERGY CONSERVATION, MATHEMATICAL ANALYSIS, MOMENTUM, NUMBERS, PROBLEM SOLVING, THEORY, ARTIFICIAL INTELLIGENCE
Subject Categories : Human Factors Engineering & Man Machine System
Computer Programming and Software
Distribution Statement : APPROVED FOR PUBLIC RELEASE