Chancellery Research - Research Publications
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ItemSearchablewords on theWeb(SPRINGER, 2005-04)
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ItemEfficient plagiarism detection for large code repositories(WILEY, 2007-02)
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ItemAccurate discovery of co-derivative documents via duplicate text detection(PERGAMON-ELSEVIER SCIENCE LTD, 2006-11)
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ItemUsing query logs to establish vocabularies in distributed information retrieval(ELSEVIER SCI LTD, 2007-01)
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ItemRobust Result Merging Using Sample-Based Score Estimates(ASSOC COMPUTING MACHINERY, 2009)In federated information retrieval, a query is routed to multiple collections and a single answer list is constructed by combining the results. Such metasearch provides a mechanism for locating documents on the hidden Web and, by use of sampling, can proceed even when the collections are uncooperative. However, the similarity scores for documents returned from different collections are not comparable, and, in uncooperative environments, document scores are unlikely to be reported. We introduce a new merging method for uncooperative environments, in which similarity scores for the sampled documents held for each collection are used to estimate global scores for the documents returned per query. This method requires no assumptions about properties such as the retrieval models used. Using experiments on a wide range of collections, we show that in many cases our merging methods are significantly more effective than previous techniques.
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ItemB-tries for disk-based string management(SPRINGER, 2009-01)
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ItemEfficient online index maintenance for contiguous inverted lists(ELSEVIER SCI LTD, 2006-07)
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ItemDetection of video sequences using compact signatures(ASSOC COMPUTING MACHINERY, 2006-01)Digital representations are widely used for audiovisual content, enabling the creation of large online repositories of video, allowing access such as video on demand. However, the ease of copying and distribution of digital video makes piracy a growing concern for content owners. We investigate methods for identifying coderivative video content---that is, video clips that are derived from the same original source. By using dynamic programming to identify regions of similarity in video signatures, it is possible to efficiently and accurately identify coderivatives, even when these regions constitute only a small section of the clip being searched. We propose four new methods for producing compact video signatures, based on the way in which the video changes over time. The intuition is that such properties are likely to be preserved even when the video is badly degraded. We demonstrate that these signatures are insensitive to dramatic changes in video bitrate and resolution, two parameters that are often altered when reencoding. In the presence of mild degradations, our methods can accurately identify copies of clips that are as short as 5 s within a dataset 140 min long. These methods are much faster than previously proposed techniques; using a more compact signature, this query can be completed in a few milliseconds.
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ItemEfficient query expansion with auxiliary data structures(PERGAMON-ELSEVIER SCIENCE LTD, 2006-11)
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ItemSample sizes for query probing in uncooperative distributed information retrieval(SPRINGER-VERLAG BERLIN, 2006)