The Ostensive Model of Developing Information-Needs

[摘要] From intuitions and informal observations of searching behaviour, a formal model is developed of cognition during a searching session. The model is of the iterative updating of an information-need by exposure of a user to information during a session. The model is path-based - using trends within the content of objects on a path to predict the current information-need. This provides contextual interpretation of objects based upon the path taken to an object. The model is ostensive in nature; however, instead of the active communicated evidence of traditional conceptions of ostension, it uses passive observational evidence. It produces a new notion of relevance: Ostensive Relevance - profiles of which are the key to the effective use of path information. The integration of the Ostensive Model and the Binary Probabilistic Model is achieved by weakening of a conventional assumption in the estimation of a probabilistic parameter. This integration effects a novel combination of objective and subjective probabilities - commonly regarded as incompatible. The Ostensive Model is instantiated in a combination of a networked IR server and a novel graphical user-interface. The interface presents a fish-eyed view of a growing multi-path browsing surface that hides internal representations and obviates querying. The hiding of internals, combined with the ability of the Ostensive Model to follow a developing information-need, makes the interface a truly media-neutral searching environment. A new test collection of general interest images with four binary relevance assessments is constructed and used for an evaluation of three Ostensive Relevance Profiles. The results are analysed in the light of different interpretations of the multiple assessments of the test-collection. The evaluation method is itself analysed and concrete proposals made for its development. The results of the evaluation provide strong encouragement for the Ostensive approach.

[发布机构] University:University of Glasgow

[关键词] Computer science