Presents a general mathematical framework for information retrieval, in which query evaluation is seen as a mapping from the free term algebra built by query descriptors and weights to the semantic algebra of evaluation value. Competing mathematical models that try to describe how retrieval systems behave are reviewed. (Author/MBR)

Reviews recent research into the use of hierarchic agglomerative clustering methods for document retrieval. The topics discussed include the calculation of interdocument similarities, algorithms used to implement clustering methods on large databases, validity testing of document hierarchies, appropriate search strategies, and other applications…

Describes a new effectiveness measure as an alternative to the traditional evaluation measures of recall and precision in information retrieval systems. The statistical approach--which compares two retrieval algorithms--is explained, the information needs of the user are considered, and an experiment with a test collection of abstracts is…