Automatic indexing based on term activity

With the increasing number of electronic documents, automatic indexing from a document is an essential approach in information retrieval systems, such as search engines. This paper proposes an automatic indexing method named PAI (Priming Activation Indexing) which extracts keywords expressing assertions of a document. The basic idea is that since an author writes a document for insisting on his/her main point, impressive terms to be born in the mind of the reader could represent the asserted keywords of the document. Our approach employs a spreading activation model to extract keywords based on the activity of terms without using corpus, thesaurus, syntactic analysis, dependency relations between terms, and the other knowledge except for stop-word list. Experimental evaluations are reported by applying PAI to both papers and the archives of a mailing-list.