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Abstract

We report data fusion experiments carried out on the four best-performing retrieval models from TREC 5. Three were conceptually/algorithmically very different from one another; one was algorithmically similar to one of the former. The objective of the test was to observe the performance of the 11 logical data fusion combinations compared to the performance of the four individual models and their intermediate fusions when following the principle of polyrepresentation. This principle is based on cognitive IR perspective (Ingwersen & Järvelin, 2005) and implies that each retrieval model is regarded as a representation of a unique interpretation of information retrieval (IR). It predicts that only fusions of very different, but equally good, IR models may outperform each constituent as well as their intermediate fusions. Two kinds of experiments were carried out. One tested restricted fusions, which entails that only the inner disjoint overlap documents between fused models are ranked. The second set of experiments was based on traditional data fusion methods. The experiments involved the 30 TREC 5 topics that contain more than 44 relevant documents. In all tests, the Borda and CombSUM scoring methods were used. Performance was measured by precision and recall, with document cutoff values (DCVs) at 100 and 15 documents, respectively. Results show that restricted fusions made of two, three, or four cognitively/algorithmically very different retrieval models perform significantly better than do the individual models at DCV100. At DCV15, however, the results of polyrepresentative fusion were less predictable. The traditional fusion method based on polyrepresentation principles demonstrates a clear picture of performance at both DCV levels and verifies the polyrepresentation predictions for data fusion in IR. Data fusion improves retrieval performance over their constituent IR models only if the models all are quite conceptually/algorithmically dissimilar and equally and well performing, in that order of importance.

Date

22. 3.2009 18:48:28

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Abstract

Connotea is a free online reference management and social bookmarking service for scientists created by Nature Publishing Group. While somewhat experimental in nature, Connotea already has a large and growing number of users, and is a real, fully functioning service. The label 'experimental' is not meant to imply that the service is any way ephemeral or esoteric, rather that the concept of social bookmarking itself and the application of that concept to reference management are both recent developments. Connotea is under active development, and we are still in the process of discovering how people will use it. In addition to Connotea being a free and public service, the core code is freely available under an open source license. Connotea was conceived from the outset as an online, social tool. Seeing the possibilities that del.icio.us was opening up for its users in the area of general web linking, we realised that scholarly reference management was a similar problem space. Connotea was designed and developed late in 2004, and soft-launched at the end of December 2004. Usage has grown over the past several months, to the point where there is now enough data in the system for interesting second-order effects to emerge. This paper will start by giving an overview of Connotea, and will outline the key concepts and describe its main features. We will then take the reader on a brief guided tour, show some of the aforementioned second-order effects, and end with a discussion of Connotea's likely future direction.

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Abstract

Nearly 25 years have elapsed since the last comprehensive measure of the percentage of academic libraries that employ the Dewey and Library of Congress systems of classification. To provide updated statistics, the researchers surveyed all 3793 academic libraries via their online catalogs. The findings indicate that the use of Dewey has declined over the past four decades. Teachers' Colleges and Community Colleges in particular have higher rates of Dewey use than large research or professional universities. This information may help support academic library reclassification decisions.