Issue No. 05 - September-October (1997 vol. 9)
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/69.634752
<p><b>Abstract</b>—Although much research in machine learning has been carried out on acquiring knowledge for problem-solving in many problem domains, little effort has been focused on learning search-control knowledge for solving optimization problems. This paper reports on the development of SHAPES, a system that learns heuristic search guidance for solving optimization problems in intractable, under-constrained domains based on the Explanation-Based Learning (EBL) framework. The system embodies two new and novel approaches to machine learning. First, it makes use of explanations of varying levels of approximation as a mean for verifying heuristic-based decisions, allowing heuristic estimates to be revised and corrected during problem-solving. The provision of such a revision mechanism is particularly important when working in intractable and under-constrained domains, where heuristics tend to be highly over-generalized, and hence at times will give rise to incorrect results. Second, it employs a new linear and quadratic programming-based weight-assignment algorithm formulated to direct search toward optimal solutions under best-first search. The algorithm offers a direct method for assigning rule strengths and, in so doing, avoids the need to address the <it>credit-assignment</it> problem faced by other iterative weight-adjustment methods.</p>
Explanation-Based Learning, heuristics, intractability, search, weight assignment.
K. P. Wong and K. P. Doan, "SHAPES: A Novel Approach for Learning Search Heuristics in Under-Constrained Optimization Problems," in IEEE Transactions on Knowledge & Data Engineering, vol. 9, no. , pp. 731-746, 1997.