More Notes from the Unification Underground: A Second Compilation of Papers on Unification-Based Formalisms.

摘要

This report is the second compilation of papers by members of the PATR group at SRI International and collaborators reporting on ongoing research on both practical and theoretical issues concerning grammar formalisms. The current formalism being simultaneously designed, implemented, and used by the group, PATR-II, is based on unification of directed-graph structures. The papers presented in this compilation describe techniques for efficiently implementing formalisms that make use of such a concept of unification. The first two chapters are devoted to the problem of representing directed graphs as data structures such that unification is efficiently implementable. The final chapter describes a general technique for extending context-free parsing methods to unification-based formalisms. The techniques described in these papers have all been implemented and tested. All three chapters are versions of papers presented at the Twenty-Third Annual Meeting of the Association for Computational Linguistics, held at the University of Chicago, Chicago, Illinois, during July 8 through 12, 1985, and appear in the proceedings of that conference. Research on PATR-II was begun as part of the KLAUS (Knowledge Learning And Using System) project at SRI, and was set up with the intention of experimenting with mathematically well-defined alternatives to the DIALOGIC natural-language processing system. The more theoretical research was made possible in part by a gift from the System Development Foundation and was conducted as part of a coordinated research effort with the Situated Language program at the Center for the Study of Language and Information, Stanford University.