Abstract

As large databases of conceptual graphs are developed for complex domains, efficient retrieval techniques must be developed to manage the complexity of graph-matching while maintaining reasonable space requirements. This paper describes a novel method "the multilevel hierarchical retrieval method" that exploits redundancy to improve both space and execution time efficiency. The method involves search in multiple partially ordered (by "more-general-than") hierarchies such that search in a simpler hierarchy reduces the search time in the hierarchy of next complexity. The specific hierarchies used are: the traditional partial order over conceptual graphs; a partial order over node descriptors; a partial order over "descriptor units"; and finally, the simplest partial order is the traditional type hierarchy. 1 Introduction Although it is true for many natural language applications that due to a wide variation of concept and relation types that matching conceptual graphs [14] is relatively...

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