Improving library subject access (ILSA): A theory of clustering based in classification

The ILSA prototype was developed using an object‐oriented multimedia user interface on six NeXT workstations with two databases: the first with 100,000 MARC records and the second with 20,000 additional records enhanced with table of contents data. The items are grouped into subject clusters consisting of the classification number and the first subject heading assigned. Every other distinct keyword in the MARC record is linked to the subject cluster in an automated natural language mapping scheme, which leads the user from the term entered to the controlled vocabulary of the subject clusters in which the term appeared. The use of a hierarchical classification number (Dewey) makes it possible to broaden or narrow a search at will.