Search (150 results, page 7 of 8)

  • × theme_ss:"Retrievalalgorithmen"
  • × year_i:[2000 TO 2010}
  1. Na, S.-H.; Kang, I.-S.; Roh, J.-E.; Lee, J.-H.: ¬An empirical study of query expansion and cluster-based retrieval in language modeling approach (2007) 0.00
    0.001674345 = product of:
      0.00334869 = sum of:
        0.00334869 = product of:
          0.00669738 = sum of:
            0.00669738 = weight(_text_:a in 906) [ClassicSimilarity], result of:
              0.00669738 = score(doc=906,freq=4.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.12611452 = fieldWeight in 906, product of:
                  2.0 = tf(freq=4.0), with freq of:
                    4.0 = termFreq=4.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.0546875 = fieldNorm(doc=906)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Abstract
    The term mismatch problem in information retrieval is a critical problem, and several techniques have been developed, such as query expansion, cluster-based retrieval and dimensionality reduction to resolve this issue. Of these techniques, this paper performs an empirical study on query expansion and cluster-based retrieval. We examine the effect of using parsimony in query expansion and the effect of clustering algorithms in cluster-based retrieval. In addition, query expansion and cluster-based retrieval are compared, and their combinations are evaluated in terms of retrieval performance by performing experimentations on seven test collections of NTCIR and TREC.
    Type
    a
  2. López-Pujalte, C.; Guerrero-Bote, V.P.; Moya-Anegón, F. de: Genetic algorithms in relevance feedback : a second test and new contributions (2003) 0.00
    0.001674345 = product of:
      0.00334869 = sum of:
        0.00334869 = product of:
          0.00669738 = sum of:
            0.00669738 = weight(_text_:a in 1076) [ClassicSimilarity], result of:
              0.00669738 = score(doc=1076,freq=4.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.12611452 = fieldWeight in 1076, product of:
                  2.0 = tf(freq=4.0), with freq of:
                    4.0 = termFreq=4.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.0546875 = fieldNorm(doc=1076)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Type
    a
  3. Sánchez-de-Madariaga, R.; Fernández-del-Castillo, J.R.: ¬The bootstrapping of the Yarowsky algorithm in real corpora (2009) 0.00
    0.001674345 = product of:
      0.00334869 = sum of:
        0.00334869 = product of:
          0.00669738 = sum of:
            0.00669738 = weight(_text_:a in 2451) [ClassicSimilarity], result of:
              0.00669738 = score(doc=2451,freq=4.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.12611452 = fieldWeight in 2451, product of:
                  2.0 = tf(freq=4.0), with freq of:
                    4.0 = termFreq=4.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.0546875 = fieldNorm(doc=2451)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Abstract
    The Yarowsky bootstrapping algorithm resolves the homograph-level word sense disambiguation (WSD) problem, which is the sense granularity level required for real natural language processing (NLP) applications. At the same time it resolves the knowledge acquisition bottleneck problem affecting most WSD algorithms and can be easily applied to foreign language corpora. However, this paper shows that the Yarowsky algorithm is significantly less accurate when applied to domain fluctuating, real corpora. This paper also introduces a new bootstrapping methodology that performs much better when applied to these corpora. The accuracy achieved in non-domain fluctuating corpora is not reached due to inherent domain fluctuation ambiguities.
    Type
    a
  4. Klein, S.T.: On the use of negation in Boolean IR queries. (2009) 0.00
    0.001674345 = product of:
      0.00334869 = sum of:
        0.00334869 = product of:
          0.00669738 = sum of:
            0.00669738 = weight(_text_:a in 3927) [ClassicSimilarity], result of:
              0.00669738 = score(doc=3927,freq=4.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.12611452 = fieldWeight in 3927, product of:
                  2.0 = tf(freq=4.0), with freq of:
                    4.0 = termFreq=4.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.0546875 = fieldNorm(doc=3927)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Abstract
    The negation operator, in various forms in which it appears in Information Retrieval queries, is investigated. The applications include negated terms in Boolean queries, more specifically in the presence of metrical constraints, but also negated characters used in the definition of extended keywords by means of regular expressions. Exact definitions are suggested and their usefulness is shown on several examples. Finally, some implementation issues are discussed, in particular as to the order in which the terms of long queries, with or without negated keywords, should be processed, and efficient heuristics for choosing a good order are suggested.
    Type
    a
  5. Bar-Ilan, J.; Levene, M.; Mat-Hassan, M.: Methods for evaluating dynamic changes in search engine rankings : a case study (2006) 0.00
    0.0015127839 = product of:
      0.0030255679 = sum of:
        0.0030255679 = product of:
          0.0060511357 = sum of:
            0.0060511357 = weight(_text_:a in 616) [ClassicSimilarity], result of:
              0.0060511357 = score(doc=616,freq=10.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.11394546 = fieldWeight in 616, product of:
                  3.1622777 = tf(freq=10.0), with freq of:
                    10.0 = termFreq=10.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.03125 = fieldNorm(doc=616)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Abstract
    Purpose - The objective of this paper is to characterize the changes in the rankings of the top ten results of major search engines over time and to compare the rankings between these engines. Design/methodology/approach - The papers compare rankings of the top-ten results of the search engines Google and AlltheWeb on ten identical queries over a period of three weeks. Only the top-ten results were considered, since users do not normally inspect more than the first results page returned by a search engine. The experiment was repeated twice, in October 2003 and in January 2004, in order to assess changes to the top-ten results of some of the queries during the three months interval. In order to assess the changes in the rankings, three measures were computed for each data collection point and each search engine. Findings - The findings in this paper show that the rankings of AlltheWeb were highly stable over each period, while the rankings of Google underwent constant yet minor changes, with occasional major ones. Changes over time can be explained by the dynamic nature of the web or by fluctuations in the search engines' indexes. The top-ten results of the two search engines had surprisingly low overlap. With such small overlap, the task of comparing the rankings of the two engines becomes extremely challenging. Originality/value - The paper shows that because of the abundance of information on the web, ranking search results is of extreme importance. The paper compares several measures for computing the similarity between rankings of search tools, and shows that none of the measures is fully satisfactory as a standalone measure. It also demonstrates the apparent differences in the ranking algorithms of two widely used search engines.
    Type
    a
  6. Henzinger, M.R.: Hyperlink analysis for the Web (2001) 0.00
    0.0015127839 = product of:
      0.0030255679 = sum of:
        0.0030255679 = product of:
          0.0060511357 = sum of:
            0.0060511357 = weight(_text_:a in 8) [ClassicSimilarity], result of:
              0.0060511357 = score(doc=8,freq=10.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.11394546 = fieldWeight in 8, product of:
                  3.1622777 = tf(freq=10.0), with freq of:
                    10.0 = termFreq=10.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.03125 = fieldNorm(doc=8)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Content
    Information retrieval is a computer science subfield whose goal is to find all documents relevant to a user query in a given collection of documents. As such, information retrieval should really be called document retrieval. Before the advent of the Web, IR systems were typically installed in libraries for use mostly by reference librarians. The retrieval algorithm for these systems was usually based exclusively on analysis of the words in the document. The Web changed all this. Now each Web user has access to various search engines whose retrieval algorithms often use not only the words in the documents but also information like the hyperlink structure of the Web or markup language tags. How are hyperlinks useful? The hyperlink functionality alone-that is, the hyperlink to Web page B that is contained in Web page A-is not directly useful in information retrieval. However, the way Web page authors use hyperlinks can give them valuable information content. Authors usually create hyperlinks they think will be useful to readers. Some may be navigational aids that, for example, take the reader back to the site's home page; others provide access to documents that augment the content of the current page. The latter tend to point to highquality pages that might be on the same topic as the page containing the hyperlink. Web information retrieval systems can exploit this information to refine searches for relevant documents. Hyperlink analysis significantly improves the relevance of the search results, so much so that all major Web search engines claim to use some type of hyperlink analysis. However, the search engines do not disclose details about the type of hyperlink analysis they perform- mostly to avoid manipulation of search results by Web-positioning companies. In this article, I discuss how hyperlink analysis can be applied to ranking algorithms, and survey other ways Web search engines can use this analysis.
    Type
    a
  7. Quiroga, L.M.; Mostafa, J.: ¬An experiment in building profiles in information filtering : the role of context of user relevance feedback (2002) 0.00
    0.0014647468 = product of:
      0.0029294936 = sum of:
        0.0029294936 = product of:
          0.005858987 = sum of:
            0.005858987 = weight(_text_:a in 2579) [ClassicSimilarity], result of:
              0.005858987 = score(doc=2579,freq=6.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.11032722 = fieldWeight in 2579, product of:
                  2.4494898 = tf(freq=6.0), with freq of:
                    6.0 = termFreq=6.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.0390625 = fieldNorm(doc=2579)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Abstract
    An experiment was conducted to see how relevance feedback could be used to build and adjust profiles to improve the performance of filtering systems. Data was collected during the system interaction of 18 graduate students with SIFTER (Smart Information Filtering Technology for Electronic Resources), a filtering system that ranks incoming information based on users' profiles. The data set came from a collection of 6000 records concerning consumer health. In the first phase of the study, three different modes of profile acquisition were compared. The explicit mode allowed users to directly specify the profile; the implicit mode utilized relevance feedback to create and refine the profile; and the combined mode allowed users to initialize the profile and to continuously refine it using relevance feedback. Filtering performance, measured in terms of Normalized Precision, showed that the three approaches were significantly different ( [small alpha, Greek] =0.05 and p =0.012). The explicit mode of profile acquisition consistently produced superior results. Exclusive reliance on relevance feedback in the implicit mode resulted in inferior performance. The low performance obtained by the implicit acquisition mode motivated the second phase of the study, which aimed to clarify the role of context in relevance feedback judgments. An inductive content analysis of thinking aloud protocols showed dimensions that were highly situational, establishing the importance context plays in feedback relevance assessments. Results suggest the need for better representation of documents, profiles, and relevance feedback mechanisms that incorporate dimensions identified in this research.
    Type
    a
  8. Ning, X.; Jin, H.; Wu, H.: RSS: a framework enabling ranked search on the semantic web (2008) 0.00
    0.0014647468 = product of:
      0.0029294936 = sum of:
        0.0029294936 = product of:
          0.005858987 = sum of:
            0.005858987 = weight(_text_:a in 2069) [ClassicSimilarity], result of:
              0.005858987 = score(doc=2069,freq=6.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.11032722 = fieldWeight in 2069, product of:
                  2.4494898 = tf(freq=6.0), with freq of:
                    6.0 = termFreq=6.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.0390625 = fieldNorm(doc=2069)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Abstract
    The semantic web not only contains resources but also includes the heterogeneous relationships among them, which is sharply distinguished from the current web. As the growth of the semantic web, specialized search techniques are of significance. In this paper, we present RSS-a framework for enabling ranked semantic search on the semantic web. In this framework, the heterogeneity of relationships is fully exploited to determine the global importance of resources. In addition, the search results can be greatly expanded with entities most semantically related to the query, thus able to provide users with properly ordered semantic search results by combining global ranking values and the relevance between the resources and the query. The proposed semantic search model which supports inference is very different from traditional keyword-based search methods. Moreover, RSS also distinguishes from many current methods of accessing the semantic web data in that it applies novel ranking strategies to prevent returning search results in disorder. The experimental results show that the framework is feasible and can produce better ordering of semantic search results than directly applying the standard PageRank algorithm on the semantic web.
    Type
    a
  9. Baeza-Yates, R.; Navarro, G.: Block addressing indices for approximate text retrieval (2000) 0.00
    0.0014351527 = product of:
      0.0028703054 = sum of:
        0.0028703054 = product of:
          0.005740611 = sum of:
            0.005740611 = weight(_text_:a in 4295) [ClassicSimilarity], result of:
              0.005740611 = score(doc=4295,freq=4.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.10809815 = fieldWeight in 4295, product of:
                  2.0 = tf(freq=4.0), with freq of:
                    4.0 = termFreq=4.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046875 = fieldNorm(doc=4295)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Abstract
    The issue of reducing the space overhead when indexing large text databases is becoming more and more important, as the text collection grow in size. Another subject, which is gaining importance as text databases grow and get more heterogeneous and error prone, is that of flexible string matching. One of the best tools to make the search more flexible is to allow a limited number of differences between the words found and those sought. This is called 'approximate text searching'. which is becoming more and more popular. In recent years some indexing schemes with very low space overhead have appeared, some of them dealing with approximate searching. These low overhead indices (whose most notorious exponent is Glimpse) are modified inverted files, where space is saved by making the lists of occurences point to text blocks instead of exact word positions. Despite their existence, little is known about the expected behaviour of these 'block addressing' indices, and even less is known when it comes to cope with approximate search. Our main contribution is an analytical study of the space-time trade-offs for indexed text searching
    Type
    a
  10. French, J.C.; Powell, A.L.; Schulman, E.: Using clustering strategies for creating authority files (2000) 0.00
    0.0014351527 = product of:
      0.0028703054 = sum of:
        0.0028703054 = product of:
          0.005740611 = sum of:
            0.005740611 = weight(_text_:a in 4811) [ClassicSimilarity], result of:
              0.005740611 = score(doc=4811,freq=4.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.10809815 = fieldWeight in 4811, product of:
                  2.0 = tf(freq=4.0), with freq of:
                    4.0 = termFreq=4.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046875 = fieldNorm(doc=4811)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Abstract
    As more online databases are integrated into digital libraries, the issue of quality control of the data becomes increasingly important, especially as it relates to the effective retrieval of information. Authority work, the need to discover and reconcile variant forms of strings in bibliographical entries, will become more critical in the future. Spelling variants, misspellings, and transliteration differences will all increase the difficulty of retrieving information. We investigate a number of approximate string matching techniques that have traditionally been used to help with this problem. We then introduce the notion of approximate word matching and show how it can be used to improve detection and categorization of variant forms. We demonstrate the utility of these approaches using data from the Astrophysics Data System and show how we can reduce the human effort involved in the creation of authority files
    Type
    a
  11. Sakai, T.: On the reliability of information retrieval metrics based on graded relevance (2007) 0.00
    0.0014351527 = product of:
      0.0028703054 = sum of:
        0.0028703054 = product of:
          0.005740611 = sum of:
            0.005740611 = weight(_text_:a in 910) [ClassicSimilarity], result of:
              0.005740611 = score(doc=910,freq=4.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.10809815 = fieldWeight in 910, product of:
                  2.0 = tf(freq=4.0), with freq of:
                    4.0 = termFreq=4.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046875 = fieldNorm(doc=910)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Abstract
    This paper compares 14 information retrieval metrics based on graded relevance, together with 10 traditional metrics based on binary relevance, in terms of stability, sensitivity and resemblance of system rankings. More specifically, we compare these metrics using the Buckley/Voorhees stability method, the Voorhees/Buckley swap method and Kendall's rank correlation, with three data sets comprising test collections and submitted runs from NTCIR. Our experiments show that (Average) Normalised Discounted Cumulative Gain at document cut-off l are the best among the rank-based graded-relevance metrics, provided that l is large. On the other hand, if one requires a recall-based graded-relevance metric that is highly correlated with Average Precision, then Q-measure is the best choice. Moreover, these best graded-relevance metrics are at least as stable and sensitive as Average Precision, and are fairly robust to the choice of gain values.
    Type
    a
  12. White, R.W.; Jose, J.M.; Ruthven, I.: ¬An implicit feedback approach for interactive information retrieval (2006) 0.00
    0.0014351527 = product of:
      0.0028703054 = sum of:
        0.0028703054 = product of:
          0.005740611 = sum of:
            0.005740611 = weight(_text_:a in 964) [ClassicSimilarity], result of:
              0.005740611 = score(doc=964,freq=4.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.10809815 = fieldWeight in 964, product of:
                  2.0 = tf(freq=4.0), with freq of:
                    4.0 = termFreq=4.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046875 = fieldNorm(doc=964)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Abstract
    Searchers can face problems finding the information they seek. One reason for this is that they may have difficulty devising queries to express their information needs. In this article, we describe an approach that uses unobtrusive monitoring of interaction to proactively support searchers. The approach chooses terms to better represent information needs by monitoring searcher interaction with different representations of top-ranked documents. Information needs are dynamic and can change as a searcher views information. The approach we propose gathers evidence on potential changes in these needs and uses this evidence to choose new retrieval strategies. We present an evaluation of how well our technique estimates information needs, how well it estimates changes in these needs and the appropriateness of the interface support it offers. The results are presented and the avenues for future research identified.
    Type
    a
  13. Zhao, L.; Wu, L.; Huang, X.: Using query expansion in graph-based approach for query-focused multi-document summarization (2009) 0.00
    0.0014351527 = product of:
      0.0028703054 = sum of:
        0.0028703054 = product of:
          0.005740611 = sum of:
            0.005740611 = weight(_text_:a in 2449) [ClassicSimilarity], result of:
              0.005740611 = score(doc=2449,freq=4.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.10809815 = fieldWeight in 2449, product of:
                  2.0 = tf(freq=4.0), with freq of:
                    4.0 = termFreq=4.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046875 = fieldNorm(doc=2449)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Abstract
    This paper presents a novel query expansion method, which is combined in the graph-based algorithm for query-focused multi-document summarization, so as to resolve the problem of information limit in the original query. Our approach makes use of both the sentence-to-sentence relations and the sentence-to-word relations to select the query biased informative words from the document set and use them as query expansions to improve the sentence ranking result. Compared to previous query expansion approaches, our approach can capture more relevant information with less noise. We performed experiments on the data of document understanding conference (DUC) 2005 and DUC 2006, and the evaluation results show that the proposed query expansion method can significantly improve the system performance and make our system comparable to the state-of-the-art systems.
    Type
    a
  14. Ding, Y.; Yan, E.; Frazho, A.; Caverlee, J.: PageRank for ranking authors in co-citation networks (2009) 0.00
    0.0014351527 = product of:
      0.0028703054 = sum of:
        0.0028703054 = product of:
          0.005740611 = sum of:
            0.005740611 = weight(_text_:a in 3161) [ClassicSimilarity], result of:
              0.005740611 = score(doc=3161,freq=4.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.10809815 = fieldWeight in 3161, product of:
                  2.0 = tf(freq=4.0), with freq of:
                    4.0 = termFreq=4.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046875 = fieldNorm(doc=3161)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Type
    a
  15. Mandl, T.: Web- und Multimedia-Dokumente : Neuere Entwicklungen bei der Evaluierung von Information Retrieval Systemen (2003) 0.00
    0.001353075 = product of:
      0.00270615 = sum of:
        0.00270615 = product of:
          0.0054123 = sum of:
            0.0054123 = weight(_text_:a in 1734) [ClassicSimilarity], result of:
              0.0054123 = score(doc=1734,freq=2.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.10191591 = fieldWeight in 1734, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.0625 = fieldNorm(doc=1734)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Type
    a
  16. Stock, W.G.: On relevance distributions (2006) 0.00
    0.001353075 = product of:
      0.00270615 = sum of:
        0.00270615 = product of:
          0.0054123 = sum of:
            0.0054123 = weight(_text_:a in 5116) [ClassicSimilarity], result of:
              0.0054123 = score(doc=5116,freq=2.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.10191591 = fieldWeight in 5116, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.0625 = fieldNorm(doc=5116)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Type
    a
  17. Vechtomova, O.; Karamuftuoglu, M.: Lexical cohesion and term proximity in document ranking (2008) 0.00
    0.001353075 = product of:
      0.00270615 = sum of:
        0.00270615 = product of:
          0.0054123 = sum of:
            0.0054123 = weight(_text_:a in 2101) [ClassicSimilarity], result of:
              0.0054123 = score(doc=2101,freq=2.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.10191591 = fieldWeight in 2101, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.0625 = fieldNorm(doc=2101)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Type
    a
  18. Crouch, C.J.; Crouch, D.B.; Chen, Q.; Holtz, S.J.: Improving the retrieval effectiveness of very short queries (2002) 0.00
    0.0011959607 = product of:
      0.0023919214 = sum of:
        0.0023919214 = product of:
          0.0047838427 = sum of:
            0.0047838427 = weight(_text_:a in 2572) [ClassicSimilarity], result of:
              0.0047838427 = score(doc=2572,freq=4.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.090081796 = fieldWeight in 2572, product of:
                  2.0 = tf(freq=4.0), with freq of:
                    4.0 = termFreq=4.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.0390625 = fieldNorm(doc=2572)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Abstract
    This paper describes an automatic approach designed to improve the retrieval effectiveness of very short queries such as those used in web searching. The method is based on the observation that stemming, which is designed to maximize recall, often results in depressed precision. Our approach is based on pseudo-feedback and attempts to increase the number of relevant documents in the pseudo-relevant set by reranking those documents based on the presence of unstemmed query terms in the document text. The original experiments underlying this work were carried out using Smart 11.0 and the lnc.ltc weighting scheme on three sets of documents from the TREC collection with corresponding TREC (title only) topics as queries. (The average length of these queries after stoplisting ranges from 2.4 to 4.5 terms.) Results, evaluated in terms of P@20 and non-interpolated average precision, showed clearly that pseudo-feedback (PF) based on this approach was effective in increasing the number of relevant documents in the top ranks. Subsequent experiments, performed on the same data sets using Smart 13.0 and the improved Lnu.ltu weighting scheme, indicate that these results hold up even over the much higher baseline provided by the new weights. Query drift analysis presents a more detailed picture of the improvements produced by this process.
    Type
    a
  19. Lanvent, A.: Know-how - Suchverfahren : Intelligente Suchmaschinen erzielen mit assoziativen und linguistischen Verfahren beste Ergebnisse. (2004) 0.00
    0.0011959607 = product of:
      0.0023919214 = sum of:
        0.0023919214 = product of:
          0.0047838427 = sum of:
            0.0047838427 = weight(_text_:a in 2988) [ClassicSimilarity], result of:
              0.0047838427 = score(doc=2988,freq=4.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.090081796 = fieldWeight in 2988, product of:
                  2.0 = tf(freq=4.0), with freq of:
                    4.0 = termFreq=4.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.0390625 = fieldNorm(doc=2988)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Type
    a
  20. Lanvent, A.: Praxis - Windows-Suche und Indexdienst : Auch Windows kann bei der Suche den Turbo einlegen: mit dem Indexdienst (2004) 0.00
    0.0011959607 = product of:
      0.0023919214 = sum of:
        0.0023919214 = product of:
          0.0047838427 = sum of:
            0.0047838427 = weight(_text_:a in 3316) [ClassicSimilarity], result of:
              0.0047838427 = score(doc=3316,freq=4.0), product of:
                0.053105544 = queryWeight, product of:
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.046056706 = queryNorm
                0.090081796 = fieldWeight in 3316, product of:
                  2.0 = tf(freq=4.0), with freq of:
                    4.0 = termFreq=4.0
                  1.153047 = idf(docFreq=37942, maxDocs=44218)
                  0.0390625 = fieldNorm(doc=3316)
          0.5 = coord(1/2)
      0.5 = coord(1/2)
    
    Type
    a

Languages

  • e 137
  • d 11
  • pt 1
  • sp 1
  • More… Less…

Types

  • a 143
  • m 5
  • el 3
  • More… Less…