tailieunhanh - Báo cáo khoa học: "REPRESENTATION OF TEXTS FOR INFORMATION RETRIEVAL"

The representation of whole texts is a major concern of the field known as information retrieval (IR), an importaunt aspect of which might more precisely be called 'document retrieval' (DR). The DR situation, with which we will be concerned, is, in general, the following: a. A user, recognizing an information need, presents to an IR mechanism (., a collection of texts, with a set of associated activities for representing, storing, matching, etc.) a request, based upon that need hoping that the mechanism will be able to satisfy that need. . | REPRESENTATION of texts for information retrieval . Belkin . Michell and . Kuehner University of Western Ontario The representation of whole texts is a major concern of the field known as information retrieval IR an important aspect of which might more precisely be called document retrieval DR . The DR situation with which we will be concerned is in general the following a. A user recognizing an information need presents to an IR mechanism . a collection of texts with a set of associated activities for representing storing matching etc. a request based upon that need hoping that the mechanism will be able to satisfy that need. b. The task of the IR mechanism is to present the user with the text s that it judges to be most likely to satisfy the user s need based upon the request. c. The user examines the text s and her his need is satisfied completely or partially or not at all. The user s judgement as to the contribution of each text in satisfying the need establishes that text s usefulness or relevance to the need. Several characteristics of the problem which DR attempts to solve make current IR systems rather different from say question-answering systems. One is that the needs which people bring to the system require in general responses consisting of documents about the topic or problem rather than specific data facts or inferences. Another is that these needs are typically not precisely specifiable being expressions of an anomaly in the user s state of knowledge. A third is that this is an essentially probabilistic rather than deterministic situation and is likely to remain so. And finally the corpus of documents in many such systems is in the order of millions of say journal articles or abstracts and the potential needs are within rather broad subject constraints unpredictable. The DR situation thus puts certain constraints upon text representation and relaxes others. The major relaxation is that it may not be necessary in such systems to produce .