Presents a formal model for specification of logical requirements of computer-based information systems that incorporates structural and dynamic aspects based on two separate models: the Logical Information Processing Structure and the Logical Information Processing Network. The model's role in systems development is discussed. (MBR)

Brief discussion of state-of-the-art of modeling complex information systems distinguishes between macrolevel and microlevel modeling of such systems. Network layout and hierarchical system models, simulation, information acquisition and dissemination, databases and information storage, and operating systems are described and assessed. Thirty-four…

Describes an iterative method of document retrieval similar to relevance feedback in that user feedback is utilized in subsequent iterations. However, this method compares retrieved documents with each other using algebraic formulae which determine the boundaries of the area that contains descriptions of relevant documents. Fifteen references are…

Provides a method for estimating precision without examining individual database documents, which requires knowledge of only the query or expressed information need and a set of database parameters constant for all queries. Concepts of historic and expected precision are examined, and applications of precision-document graphs are assessed. (36…

Reviews previous investigations of how best to determine whether a user should continue to display output from an online retrieval system, and presents a model for providing the user with the estimated number of relevant records remaining in a retrieved set ranked by a retrieval status value. (40 references) (Author/CLB)

Develops an approach for advance estimation of user charges based on information actually retrieved by searching numeric databases, and defines a method for query cardinality estimation. Based on the relational data model, which uses relational algebra, this method uses formal file descriptions to describe the database files. (LRW)

Describes a new Boolean retrieval environment in which an extended soft Boolean logic is used to automatically construct queries from original natural language formulations provided by users. Experimental results that compare the retrieval effectiveness of this method to conventional Boolean and vector processing are discussed. (27 references)…

Presents a relational logical model to support a sophisticated document retrieval system in which flexible forms of inferential and associative searching can be performed, and provides examples of ad hoc inquiries. Several problems of particular importance to document retrieval are discussed in terms of this model. (27 references) (Author/CLB)

Presents an analytical approach to the interpretation of weighted Boolean queries. By distinguishing query term weights from query weights, a query becomes a means of describing classes of ideal documents and expressing relativity criteria among these descriptions. A formalization of query term weights is given in a fuzzy set theoretical context.…