Information Retrieval System*

An effective man-machine interactive retrieval system is not achieved by simply placing a terminal on each end of an existing machine retrieval system. An interactive system requires a sequence of steps in which man and machine alternately take action. It should also provide different levels of services to experienced and inex-perienced searches, recognize the difference between a narrow and broad query, furnish clues as to the next direction to be searched, reorganize the data base dynamically as the searcher changes his view-point, provide a ranking of responses in the most likely sequence and offer the searcher the option of overriding the ranking when a par-ticularterm is of extreme significance. An online interactive system meeting many of these needs has been developed and tested. The object~ve of the.development of this system, BROWSER, was to investigate the effectiveness of a free-form query with a combinatorial search algorithm and the effectiveness of various techniques and components to facilitate online browsing. NATIONAL TECHNICA