Search (3 results, page 1 of 1)

  • × author_ss:"Lee, D.L."
  • × theme_ss:"Retrievalalgorithmen"
  1. Dang, E.K.F.; Luk, R.W.P.; Allan, J.; Ho, K.S.; Chung, K.F.L.; Lee, D.L.: ¬A new context-dependent term weight computed by boost and discount using relevance information (2010) 0.00 
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    Abstract
    We studied the effectiveness of a new class of context-dependent term weights for information retrieval. Unlike the traditional term frequency-inverse document frequency (TF-IDF), the new weighting of a term t in a document d depends not only on the occurrence statistics of t alone but also on the terms found within a text window (or "document-context") centered on t. We introduce a Boost and Discount (B&D) procedure which utilizes partial relevance information to compute the context-dependent term weights of query terms according to a logistic regression model. We investigate the effectiveness of the new term weights compared with the context-independent BM25 weights in the setting of relevance feedback. We performed experiments with title queries of the TREC-6, -7, -8, and 2005 collections, comparing the residual Mean Average Precision (MAP) measures obtained using B&D term weights and those obtained by a baseline using BM25 weights. Given either 10 or 20 relevance judgments of the top retrieved documents, using the new term weights yields improvement over the baseline for all collections tested. The MAP obtained with the new weights has relative improvement over the baseline by 3.3 to 15.2%, with statistical significance at the 95% confidence level across all four collections.
    Type
    a
  2. Couvreur, T.R.; Benzel, R.N.; Miller, S.F.; Zeitler, D.N.; Lee, D.L.; Singhal, M.; Shivaratri, N.; Wong, W.Y.P.: ¬An analysis of performance and cost factors in searching large text databases using parallel search systems (1994) 0.00 
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    Abstract
    The results of modelling the performance of searching large text databases (>10 GBytes) via various parallel hardware architectures and search algorithms are discussed. The performance under load and the cost of each configuration are compared. Strengths, weaknesses, performance sensitivities, and search features supported for each configuration are also addressed. In addition, a common search workload used in the modelling is described. The search workload is derived from a set of searches run against the Chemical Abstracts file of bibliographic and abstract text available on STN International. This common workload is applied to all configurations modelled to provide a common basis of comparison
    Type
    a
  3. Lee, D.L.; Ren, L.: Document ranking on weight-partitioned signature files (1996) 0.00 
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    Abstract
    Proposes the weight partitioned signature file, a signature file organization for supporting document ranking. It uses multiple signature files each corresponding to one term frequency to represent terms with different term frequencies. Words with the same term frequency in a document are grouped together and hased into the signature file corresponding to that term frequency. Investigates the effect of false drops on retrieval effectiveness. Analyses the performance of the weight partitioned signature file under different search strategies and configurations. Obtains an optimal formula for storage allocation to minimise the effect of false drops on document ranks. Analytical results are supported by experiments on document collections
    Type
    a

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