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Different users of a Web-based information system will have different goals and different ways of performing their work. This article explores the possibility that we can automatically detect usage patterns without demographic information about the individuals. First, a set of 47 variables was defined that can be used to characterize a user session. The(More)
Users move from one state (or task) to another in an information system's labyrinth as they try to accomplish their work, and the amount of time they spend in each state varies. This article uses continuous-time stochas-tic models, mainly based on semi-Markov chains, to derive user state transition patterns (both in rates and in probabilities) in a(More)
Mechanisms of cell-cell recognition and structural changes of growth cones (g.c.) and target membranes during contact formation are poorly understood. To examine these issues, we obtained a high magnification, real-time record of stable contact formation in cultured cells from the hippocampal CA1 area in the newborn rat. We used differential interference(More)
This paper describes a computer program which converts the text of user input and system responses from an on-line search system into fixed format records which describe the interaction. It also outlines the syntax of the query language and the format of the output record produced by the parser. The study discusses problems in constructing the parser. the(More)
This article examines the usage patterns of the ELHILL retrieval program of the National Library of Medicine's MEDLARS system. Based on a sample of 6759 searches, the study analyzes the frequency of various commands and command options, classifies messages issued by the system, and investigates searcher error rates. The article concludes with suggestions(More)
The Internet Web environment opens up extraordinary information are changing rapidly. Daily, hundreds of opportunities for user access to information. Techniques thousands of individuals use the Internet and Web for monitoring users and systems and for evaluating sys-browsers like Netscape to obtain a much broader range tem design and performance have not(More)