This report describes the development of computer programs called user agents, which, through interaction with users, can either learn new facts and store them in a data base or learn new procedures for data manipulation and represent them as programs. These programs are written in RITA, the Rule-directed Interactive Transaction Agent system, and…

Discusses impact of three selected command language facilities (positional or free text operations, crossfile searching, term frequency analysis--ZOOM) on the man-system interface in relation to operational online information retrieval (IR). A cognitive IR model, searchers' knowledge structures, and searching with different types of command…