The QA system
James R. Driscoll, Jennifer Lautenschlager, Mimi Zhao · Text REtrieval Conference · 1992
In the GA system, semantic information is combined with keywords to measure similarity between natural language queries and documents. A combination of keyword relevance and semantic relevance is achieved by treating keyword weights and semantic weights alike using the vector processing model as a basis for the combination. The approach is based on (1) the database concept of semantic modeling and (2) the linguistic concept of thematic roles. Semantic information is stored in a lexicon built manually using information found in Roget's thesaurus