摘要: This dissertation explores techniques to improve full text information retrieval by experienced computer users who are novice users of retrieval systems. An expert system which automatically reformulates Boolean user queries to im... 展开 This dissertation explores techniques to improve full text information retrieval by experienced computer users who are novice users of retrieval systems. An expert system which automatically reformulates Boolean user queries to improve search results is presented. The expert system differs from other intelligent database functions in two ways: it works with semantically and syntactically unprocessed text; and the expert system contains a knowledge base of domain independent search strategies. The passages retrieved are presented to the user in decreasing order of estimated relevancy. This combination of user interface features provides powerful, yet simple, access to full-text documents. Experimental results demonstrate that the expert system can improve the search efficiency of novice searchers without decreasing their search effectiveness. Further, an evaluation of the ranking algorithm confirms that, in general, the system presents potentially relevant passages to the user before irrelevant passages. 收起