Automatic Construction of a Knowledge Base by Analysing Texts in Natural Language

Abstract

We present a system which translat es sentences from a subset of German into a database. This database will function as the basis for a question-ans. wering-system. The system is applied to a complete text and not to isolated sentences. As an intermediate stage between the German text and th e database we use the Discourse Representation Structures (DRS) invented by Hans Kamp . Kamp's system has been cho sen because it handles intrasentential and intersentential relations uniformly. Within Kamp's system one can account for certain types of anaphoric relations for which no ot her linguistic theory has provided a solution . The input to our system is analysed by a parser which is based on lexical functional grammar. This is the first attempt to combine research on discourse representation with lexical functional grammar with the help of the formalism of Definite Clause Grammar. For the construction of the database out ofthe DRS ' s , two solutions are proposed. First , a translation of the DRS's into a set of PROLOG clau-ses enriched with some additional deductive princi. ples. Second , the formulation of inference rules which operate directly on the DRS .