Describes the architecture and functioning of a system developed specifically for text processing applications--such as information retrieval--that can benefit from structural comparisons between elements of text, such as queries and abstracts. The general ways in which the system performs matches and the ways in which this objective influenced…

Describes two computer programs--INDEX and INDEXD--that use statistical information about repeated phrases in documents to automatically index documents at the conceptual level. Sample output of the programs is provided, and plans to combine this method with linguistic and artificial intelligence techniques to provide a general conceptual…

Describes the possible improvements in the quality of automatic indexing systems gained by using complex descriptors, and reports on the effectiveness of a simple nonsyntactic phrase indexing procedure. The discussion covers shortcomings of this approach, possible methods for improvement, and areas needing further research. (43 references) (CLB)

Presents an algorithm for use in natural language document retrieval systems which automatically determines if the conjunction "and" in a statement representing an information need should be translated into a Boolean "and" or "or." The results of an experiment that used the algorithm are reported, and further research is suggested. (CLB)