This two-part article combines a comprehensive account of a probabilistic model of retrieval with new systematic experiments on TREC (Text Retrieval Conferences) Program material. Part 1 covers the foundations and the model development for document collection and relevance data, along with the test apparatus. Data and results tables for both parts…

A comprehensive account of a probabilistic model of retrieval with new systematic experiments on TREC (Text Retrieval Conferences) Program material. Part 2 covers the further development of the model, with testing, and briefly considers other environment conditions and tasks, model training, concluding with comparisons with other approaches and an…

Describes an approximate document ranking process that uses a compact array of in-memory, low-precision approximations for document length. Combined with another rule for reducing the memory required by partial similarity accumulators, the approximation heuristic allows the ranking of large document collections using less than one byte of memory…

Discusses a list of characteristics (dimensions) that are crucial for data model quality. Fourteen quality dimensions are singled out and organized in six categories: content, scope, level of detail, composition, consistency, and reaction to change. Two types of correlations among dimensions called "reinforcements" and…

Presents a relevance-feedback strategy that improves the effectiveness of information-retrieval systems based on back-propagation of the relevance of retrieved documents using an algorithm developed in a neural approach. Describes a neural information-retrieval model and reports results obtained with the algorithm in three different environments.…

Extends connections between retrospective citation age studies and reliability theory by considering the failure rate function from reliability, re-interpreted as the age-specific citation rate (ASCR). This is linked to earlier studies of retrospective citation distributions by Egghe and Ravichandra Rao who introduced a function claimed to…

Analyzes relevance assessments of topical descriptors for bibliographic records for two dimensions: (1) a vertical conceptual hierarchy of broad to narrow descriptors, and (2) a horizontal linkage of related terms. The data were analyzed for a semantic distance and semantic direction effect as postulated by the Semantic Distance Model. (Author/LRW)

Describes a study that computed the low performance standards for queries in 17 test collections. Predicted by the hypergeometric distribution, the standards represent the highest level of retrieval effectiveness attributable to chance. Operational levels of performance for vector-space and other retrieval models were compared to the standards.…

Examines four working steps from an empirical model where an expert abstractor discovers what a paper is about and drafts a topic sentence; a simulation system is developed using this model. Discusses knowledge processing activities of professional summarizing. Results indicate that a small simulation model of professional summarizing is feasible.…

Reports on the performance of the vector space model in the presence of OCR (optical character recognition) errors in information retrieval. Highlights include precision and recall, a full-text test collection, smart vector representation, impact of weighting parameters, ranking variability, and the effect of relevance feedback. (Author/LRW)

Describes an empirical evaluation that investigated the criteria by which designers of human-machine systems evaluate design information. Professional designers of nuclear power plant control rooms rated hypothetical information search questions in terms of relevance, importance, cost, and effort based on Rouse's model of information search…