Study on the automatic indexing system compared with the simi-automatic indexing system

Abstract

This thesis describes a fully automated indexing system for an information retrieval system. In information retrieval, indexing is the task consisting of the assignment to-stored records and incoming information requests of the content identifiers capable of representing records or query contents. The indexing system described in this thesis is performed automatically excluding any manual labour. The procedures necessary to implement this automatic indexing system are laxical analysis, stop-list construction, thesaurus construction. Initially, the dictionaries are constructed in the form of the ISAM file structure using the selected index terms. Afterwards, when the updating of the dictionaries is necessary, the dictionary can be enlarged by adding the supplementary index terms automatically. Since the available main memory to a user program may be limited for implementation of the automatic indexing system described in this thesis, the technique of chaining is used. The performances of the semi-automatic indexing and the fully automatic indexing system proposed in this thesis are compared. The steps of the enlargement of the dictionary are also shown. As the document abstracts are processed the size of the dictionary is gradually enlarged automatically. The graph of the documants size vs. the dictionary size is shown in the appendix.