Describes results of a study that investigated the effect of variations in indexing exhaustivity on retrieval performance in a vector space retrieval system. The test collection of documents in the National Library of Medicine's Medline file indexed under cystic fibrosis is described, and use of the SMART information retrieval system is discussed.…

Presents two partitioning methods for signature files and a method of fast weight computation to implement a document ranking strategy. Storage requirements, number of disk accesses, and processing time for these methods are compared with two other access methods. Merits of the partitioning methods are summarized. (20 references) (MES)

Describes a computerized information retrieval system that uses three agglomerative hierarchic clustering algorithms--single link, complete link, and group average link--and explains their implementations. It is noted that these implementations have been used to cluster a collection of 12,000 documents. (LRW)

Introduces two distribution schemes that partition documents over multiple processors and the corresponding multiprocessor retrieval algorithms that match relevant documents to user queries. The suggested framework is based on a general purpose hypercube multicomputer architecture with a dedicated disk for each node. A timing analysis for the…

Presents a method for using the amount of semantic information in search-query terms as a weighting factor in constructing a fuzzy relation of resemblance between retrieved items in information retrieval online. Two tables, two figures, and a reference list accompany the text. (Author/JL)

Analyzes recent developments in the problem of processing queries expressed as Boolean expressions, shows that the concept of threshold values resolves the problems inherent with relevance weights, and explores possible evaluation mechanisms for document retrieval based on fuzzy set theory. Sixteen references are listed. (FM)

Discussion of retrieval overlap and relevant overlap focuses on an analysis of data from an earlier study on overlap among document representations. This new analysis investigated the odds that an item was judged relevant when it was retrieved by two search fields as opposed to being retrieved by only one field. (Contains 17 references.) (LRW)

Describes the System for Conceptual Information Summarization, Organization, and Retrieval (SCISOR), which is designed to parse and understand short newspaper stories on corporate takeovers. Highlights include issues involved in developing memory organization and retrieval components, theoretical considerations involved in the system design, and a…

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)

Presents a manually constructed knowledge representation aimed at increasing the effectiveness of information retrieval systems. The framework of first order theories is used to analyze the properties of this new structure. The analysis demonstrates that the retrieval function takes term dependencies into account and distinguishes between…

Discusses the PRECALL, PRR (probability of relevance given retrieval), and EP (expected precision) approaches for dealing with the problem of weak ordering in information retrieval systems. Findings of two experiments comparing evaluation results obtained by PRR and EP are reported. Several mathematical formulas and proofs are included. (20…

Compares two methods of information retrieval--one that rates documents according to a query and another that uses relevant documents to find further relevant documents (i.e., neighboring documents). Highlights include experiments at the National Library of Medicine; feedback; vector cosine retrieval; and a measure of retrieval effectiveness…

Presents a model that places Boolean database queries into conjunctive normal form, thereby allowing probabilistic ranking of documents and the incorporation of relevance feedback. Experimental results compare the performance of a sequential learning probabilistic retrieval model with the proposed integrated Boolean probabilistic model and a fuzzy…

Explains an experiment in text-searching retrieval for cancer questions which developed and used computer procedures (via human simulation) to select search words from medical dictionaries. This study is based on an earlier one in which search words were humanly selected, and the recall results of the two studies are compared. (Author/LRW)

Empirical significance of document partitions is investigated as a function of index term-weight and similarity thresholds. Results show the same empirically preferred partitions can be detected by two independent strategies: an analysis of cluster-based retrieval analysis and an analysis of regularities in the underlying structure of the document…