Search (87 results, page 1 of 5)

  • × author_ss:"Leydesdorff, L."
  1. Leydesdorff, L.; Bornmann, L.; Mutz, R.; Opthof, T.: Turning the tables on citation analysis one more time : principles for comparing sets of documents (2011) 0.03
    0.029484728 = product of:
      0.081083 = sum of:
        0.0040582716 = weight(_text_:a in 4485) [ClassicSimilarity], result of:
          0.0040582716 = score(doc=4485,freq=6.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.13239266 = fieldWeight in 4485, product of:
              2.4494898 = tf(freq=6.0), with freq of:
                6.0 = termFreq=6.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.046875 = fieldNorm(doc=4485)
        0.04318126 = weight(_text_:r in 4485) [ClassicSimilarity], result of:
          0.04318126 = score(doc=4485,freq=10.0), product of:
            0.088001914 = queryWeight, product of:
              3.3102584 = idf(docFreq=4387, maxDocs=44218)
              0.026584605 = queryNorm
            0.49068546 = fieldWeight in 4485, product of:
              3.1622777 = tf(freq=10.0), with freq of:
                10.0 = termFreq=10.0
              3.3102584 = idf(docFreq=4387, maxDocs=44218)
              0.046875 = fieldNorm(doc=4485)
        0.0020832212 = weight(_text_:s in 4485) [ClassicSimilarity], result of:
          0.0020832212 = score(doc=4485,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.072074346 = fieldWeight in 4485, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.046875 = fieldNorm(doc=4485)
        0.03176025 = weight(_text_:k in 4485) [ClassicSimilarity], result of:
          0.03176025 = score(doc=4485,freq=4.0), product of:
            0.09490114 = queryWeight, product of:
              3.569778 = idf(docFreq=3384, maxDocs=44218)
              0.026584605 = queryNorm
            0.33466667 = fieldWeight in 4485, product of:
              2.0 = tf(freq=4.0), with freq of:
                4.0 = termFreq=4.0
              3.569778 = idf(docFreq=3384, maxDocs=44218)
              0.046875 = fieldNorm(doc=4485)
      0.36363637 = coord(4/11)
    
    Abstract
    We submit newly developed citation impact indicators based not on arithmetic averages of citations but on percentile ranks. Citation distributions are-as a rule-highly skewed and should not be arithmetically averaged. With percentile ranks, the citation score of each paper is rated in terms of its percentile in the citation distribution. The percentile ranks approach allows for the formulation of a more abstract indicator scheme that can be used to organize and/or schematize different impact indicators according to three degrees of freedom: the selection of the reference sets, the evaluation criteria, and the choice of whether or not to define the publication sets as independent. Bibliometric data of seven principal investigators (PIs) of the Academic Medical Center of the University of Amsterdam are used as an exemplary dataset. We demonstrate that the proposed family indicators [R(6), R(100), R(6, k), R(100, k)] are an improvement on averages-based indicators because one can account for the shape of the distributions of citations over papers.
    Source
    Journal of the American Society for Information Science and Technology. 62(2011) no.7, S.1370-1381
    Type
    a
  2. Leydesdorff, L.; Bornmann, L.; Wagner, C.S.: ¬The relative influences of government funding and international collaboration on citation impact (2019) 0.01
    0.013614261 = product of:
      0.037439216 = sum of:
        0.0052392064 = weight(_text_:a in 4681) [ClassicSimilarity], result of:
          0.0052392064 = score(doc=4681,freq=10.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.1709182 = fieldWeight in 4681, product of:
              3.1622777 = tf(freq=10.0), with freq of:
                10.0 = termFreq=10.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.046875 = fieldNorm(doc=4681)
        0.019311246 = weight(_text_:r in 4681) [ClassicSimilarity], result of:
          0.019311246 = score(doc=4681,freq=2.0), product of:
            0.088001914 = queryWeight, product of:
              3.3102584 = idf(docFreq=4387, maxDocs=44218)
              0.026584605 = queryNorm
            0.2194412 = fieldWeight in 4681, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              3.3102584 = idf(docFreq=4387, maxDocs=44218)
              0.046875 = fieldNorm(doc=4681)
        0.0020832212 = weight(_text_:s in 4681) [ClassicSimilarity], result of:
          0.0020832212 = score(doc=4681,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.072074346 = fieldWeight in 4681, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.046875 = fieldNorm(doc=4681)
        0.010805541 = product of:
          0.021611081 = sum of:
            0.021611081 = weight(_text_:22 in 4681) [ClassicSimilarity], result of:
              0.021611081 = score(doc=4681,freq=2.0), product of:
                0.09309476 = queryWeight, product of:
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.026584605 = queryNorm
                0.23214069 = fieldWeight in 4681, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.046875 = fieldNorm(doc=4681)
          0.5 = coord(1/2)
      0.36363637 = coord(4/11)
    
    Abstract
    A recent publication in Nature reports that public R&D funding is only weakly correlated with the citation impact of a nation's articles as measured by the field-weighted citation index (FWCI; defined by Scopus). On the basis of the supplementary data, we up-scaled the design using Web of Science data for the decade 2003-2013 and OECD funding data for the corresponding decade assuming a 2-year delay (2001-2011). Using negative binomial regression analysis, we found very small coefficients, but the effects of international collaboration are positive and statistically significant, whereas the effects of government funding are negative, an order of magnitude smaller, and statistically nonsignificant (in two of three analyses). In other words, international collaboration improves the impact of research articles, whereas more government funding tends to have a small adverse effect when comparing OECD countries.
    Date
    8. 1.2019 18:22:45
    Source
    Journal of the Association for Information Science and Technology. 70(2019) no.2, S.198-201
    Type
    a
  3. Rotolo, D.; Leydesdorff, L.: Matching Medline/PubMed data with Web of Science: A routine in R language (2015) 0.01
    0.009294419 = product of:
      0.034079533 = sum of:
        0.0046860883 = weight(_text_:a in 2224) [ClassicSimilarity], result of:
          0.0046860883 = score(doc=2224,freq=8.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.15287387 = fieldWeight in 2224, product of:
              2.828427 = tf(freq=8.0), with freq of:
                8.0 = termFreq=8.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.046875 = fieldNorm(doc=2224)
        0.027310224 = weight(_text_:r in 2224) [ClassicSimilarity], result of:
          0.027310224 = score(doc=2224,freq=4.0), product of:
            0.088001914 = queryWeight, product of:
              3.3102584 = idf(docFreq=4387, maxDocs=44218)
              0.026584605 = queryNorm
            0.3103367 = fieldWeight in 2224, product of:
              2.0 = tf(freq=4.0), with freq of:
                4.0 = termFreq=4.0
              3.3102584 = idf(docFreq=4387, maxDocs=44218)
              0.046875 = fieldNorm(doc=2224)
        0.0020832212 = weight(_text_:s in 2224) [ClassicSimilarity], result of:
          0.0020832212 = score(doc=2224,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.072074346 = fieldWeight in 2224, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.046875 = fieldNorm(doc=2224)
      0.27272728 = coord(3/11)
    
    Abstract
    We present a novel routine, namely medlineR, based on the R language, that allows the user to match data from Medline/PubMed with records indexed in the ISI Web of Science (WoS) database. The matching allows exploiting the rich and controlled vocabulary of medical subject headings (MeSH) of Medline/PubMed with additional fields of WoS. The integration provides data (e.g., citation data, list of cited reference, list of the addresses of authors' host organizations, WoS subject categories) to perform a variety of scientometric analyses. This brief communication describes medlineR, the method on which it relies, and the steps the user should follow to perform the matching across the two databases. To demonstrate the differences from Leydesdorff and Opthof (Journal of the American Society for Information Science and Technology, 64(5), 1076-1080), we conclude this artcle by testing the routine on the MeSH category "Burgada syndrome."
    Source
    Journal of the Association for Information Science and Technology. 66(2015) no.10, S.2155-2159
    Type
    a
  4. Ye, F.Y.; Yu, S.S.; Leydesdorff, L.: ¬The Triple Helix of university-industry-government relations at the country level and its dynamic evolution under the pressures of globalization (2013) 0.01
    0.009284975 = product of:
      0.034044906 = sum of:
        0.0052392064 = weight(_text_:a in 1110) [ClassicSimilarity], result of:
          0.0052392064 = score(doc=1110,freq=10.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.1709182 = fieldWeight in 1110, product of:
              3.1622777 = tf(freq=10.0), with freq of:
                10.0 = termFreq=10.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.046875 = fieldNorm(doc=1110)
        0.0020832212 = weight(_text_:s in 1110) [ClassicSimilarity], result of:
          0.0020832212 = score(doc=1110,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.072074346 = fieldWeight in 1110, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.046875 = fieldNorm(doc=1110)
        0.026722478 = weight(_text_:u in 1110) [ClassicSimilarity], result of:
          0.026722478 = score(doc=1110,freq=4.0), product of:
            0.08704981 = queryWeight, product of:
              3.2744443 = idf(docFreq=4547, maxDocs=44218)
              0.026584605 = queryNorm
            0.30697915 = fieldWeight in 1110, product of:
              2.0 = tf(freq=4.0), with freq of:
                4.0 = termFreq=4.0
              3.2744443 = idf(docFreq=4547, maxDocs=44218)
              0.046875 = fieldNorm(doc=1110)
      0.27272728 = coord(3/11)
    
    Abstract
    Using data from the Web of Science (WoS), we analyze the mutual information among university, industry, and government addresses (U-I-G) at the country level for a number of countries. The dynamic evolution of the Triple Helix can thus be compared among developed and developing nations in terms of cross-sectional coauthorship relations. The results show that the Triple Helix interactions among the three subsystems U-I-G become less intensive over time, but unequally for different countries. We suggest that globalization erodes local Triple Helix relations and thus can be expected to have increased differentiation in national systems since the mid-1990s. This effect of globalization is more pronounced in developed countries than in developing ones. In the dynamic analysis, we focus on a more detailed comparison between China and the United States. Specifically, the Chinese Academy of the (Social) Sciences is changing increasingly from a public research institute to an academic one, and this has a measurable effect on China's position in the globalization.
    Source
    Journal of the American Society for Information Science and Technology. 64(2013) no.11, S.2317-2325
    Type
    a
  5. Leydesdorff, L.: ¬The construction and globalization of the knowledge base in inter-human communication systems (2003) 0.01
    0.008751635 = product of:
      0.024066996 = sum of:
        0.0054389704 = product of:
          0.010877941 = sum of:
            0.010877941 = weight(_text_:h in 1621) [ClassicSimilarity], result of:
              0.010877941 = score(doc=1621,freq=2.0), product of:
                0.0660481 = queryWeight, product of:
                  2.4844491 = idf(docFreq=10020, maxDocs=44218)
                  0.026584605 = queryNorm
                0.16469726 = fieldWeight in 1621, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  2.4844491 = idf(docFreq=10020, maxDocs=44218)
                  0.046875 = fieldNorm(doc=1621)
          0.5 = coord(1/2)
        0.0057392623 = weight(_text_:a in 1621) [ClassicSimilarity], result of:
          0.0057392623 = score(doc=1621,freq=12.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.18723148 = fieldWeight in 1621, product of:
              3.4641016 = tf(freq=12.0), with freq of:
                12.0 = termFreq=12.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.046875 = fieldNorm(doc=1621)
        0.0020832212 = weight(_text_:s in 1621) [ClassicSimilarity], result of:
          0.0020832212 = score(doc=1621,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.072074346 = fieldWeight in 1621, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.046875 = fieldNorm(doc=1621)
        0.010805541 = product of:
          0.021611081 = sum of:
            0.021611081 = weight(_text_:22 in 1621) [ClassicSimilarity], result of:
              0.021611081 = score(doc=1621,freq=2.0), product of:
                0.09309476 = queryWeight, product of:
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.026584605 = queryNorm
                0.23214069 = fieldWeight in 1621, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.046875 = fieldNorm(doc=1621)
          0.5 = coord(1/2)
      0.36363637 = coord(4/11)
    
    Abstract
    The relationship between the "knowledge base" and the "globalization" of communication systems is discussed from the perspective of communication theory. I argue that inter-human communication takes place at two levels. At the first level information is exchanged and provided with meaning and at the second level meaning can reflexively be communicated. Human language can be considered as the evolutionary achievement which enables us to use these two channels of communication simultaneously. Providing meaning with hindsight is a recursive operation: a meaning that makes a difference can be considered as knowledge. If the production of knowledge is socially organized, the perspective of hindsight can further be codified. This adds globalization to the historically stabilized patterns of communications. Globalization can be expected to transform the communications in an evolutionary mode. However, the self-organization of a knowledge-based society remains an expectation with the status of a hypothesis.
    Date
    22. 5.2003 19:48:04
    Source
    Canadian Journal of Communication 28(2003), H.3, S. -
    Type
    a
  6. Shelton, R.D.; Leydesdorff, L.: Publish or patent : bibliometric evidence for empirical trade-offs in national funding strategies (2012) 0.01
    0.007871058 = product of:
      0.028860545 = sum of:
        0.0043660053 = weight(_text_:a in 70) [ClassicSimilarity], result of:
          0.0043660053 = score(doc=70,freq=10.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.14243183 = fieldWeight in 70, product of:
              3.1622777 = tf(freq=10.0), with freq of:
                10.0 = termFreq=10.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.0390625 = fieldNorm(doc=70)
        0.022758523 = weight(_text_:r in 70) [ClassicSimilarity], result of:
          0.022758523 = score(doc=70,freq=4.0), product of:
            0.088001914 = queryWeight, product of:
              3.3102584 = idf(docFreq=4387, maxDocs=44218)
              0.026584605 = queryNorm
            0.25861394 = fieldWeight in 70, product of:
              2.0 = tf(freq=4.0), with freq of:
                4.0 = termFreq=4.0
              3.3102584 = idf(docFreq=4387, maxDocs=44218)
              0.0390625 = fieldNorm(doc=70)
        0.0017360178 = weight(_text_:s in 70) [ClassicSimilarity], result of:
          0.0017360178 = score(doc=70,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.060061958 = fieldWeight in 70, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.0390625 = fieldNorm(doc=70)
      0.27272728 = coord(3/11)
    
    Abstract
    Multivariate linear regression models suggest a trade-off in allocations of national research and development (R&D). Government funding and spending in the higher education sector encourage publications as a long-term research benefit. Conversely, other components such as industrial funding and spending in the business sector encourage patenting. Our results help explain why the United States trails the European Union in publications: The focus in the United States is on industrial funding-some 70% of its total R&D investment. Likewise, our results also help explain why the European Union trails the United States in patenting, since its focus on government funding is less effective than industrial funding in predicting triadic patenting. Government funding contributes negatively to patenting in a multiple regression, and this relationship is significant in the case of triadic patenting. We provide new forecasts about the relationships of the United States, the European Union, and China for publishing; these results suggest much later dates for changes than previous forecasts because Chinese growth has been slowing down since 2003. Models for individual countries might be more successful than regression models whose parameters are averaged over a set of countries because nations can be expected to differ historically in terms of the institutional arrangements and funding schemes.
    Source
    Journal of the American Society for Information Science and Technology. 63(2012) no.3, S.498-511
    Type
    a
  7. Egghe, L.; Leydesdorff, L.: ¬The relation between Pearson's correlation coefficient r and Salton's cosine measure (2009) 0.01
    0.0072637293 = product of:
      0.026633674 = sum of:
        0.0052392064 = weight(_text_:a in 2803) [ClassicSimilarity], result of:
          0.0052392064 = score(doc=2803,freq=10.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.1709182 = fieldWeight in 2803, product of:
              3.1622777 = tf(freq=10.0), with freq of:
                10.0 = termFreq=10.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.046875 = fieldNorm(doc=2803)
        0.019311246 = weight(_text_:r in 2803) [ClassicSimilarity], result of:
          0.019311246 = score(doc=2803,freq=2.0), product of:
            0.088001914 = queryWeight, product of:
              3.3102584 = idf(docFreq=4387, maxDocs=44218)
              0.026584605 = queryNorm
            0.2194412 = fieldWeight in 2803, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              3.3102584 = idf(docFreq=4387, maxDocs=44218)
              0.046875 = fieldNorm(doc=2803)
        0.0020832212 = weight(_text_:s in 2803) [ClassicSimilarity], result of:
          0.0020832212 = score(doc=2803,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.072074346 = fieldWeight in 2803, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.046875 = fieldNorm(doc=2803)
      0.27272728 = coord(3/11)
    
    Abstract
    The relation between Pearson's correlation coefficient and Salton's cosine measure is revealed based on the different possible values of the division of the L1-norm and the L2-norm of a vector. These different values yield a sheaf of increasingly straight lines which together form a cloud of points, being the investigated relation. The theoretical results are tested against the author co-citation relations among 24 informetricians for whom two matrices can be constructed, based on co-citations: the asymmetric occurrence matrix and the symmetric co-citation matrix. Both examples completely confirm the theoretical results. The results enable us to specify an algorithm that provides a threshold value for the cosine above which none of the corresponding Pearson correlations would be negative. Using this threshold value can be expected to optimize the visualization of the vector space.
    Source
    Journal of the American Society for Information Science and Technology. 60(2009) no.5, S.1027-1036
    Type
    a
  8. Ye, F.Y.; Leydesdorff, L.: ¬The "academic trace" of the performance matrix : a mathematical synthesis of the h-index and the integrated impact indicator (I3) (2014) 0.01
    0.005590738 = product of:
      0.020499371 = sum of:
        0.013597427 = product of:
          0.027194854 = sum of:
            0.027194854 = weight(_text_:h in 1237) [ClassicSimilarity], result of:
              0.027194854 = score(doc=1237,freq=18.0), product of:
                0.0660481 = queryWeight, product of:
                  2.4844491 = idf(docFreq=10020, maxDocs=44218)
                  0.026584605 = queryNorm
                0.41174316 = fieldWeight in 1237, product of:
                  4.2426405 = tf(freq=18.0), with freq of:
                    18.0 = termFreq=18.0
                  2.4844491 = idf(docFreq=10020, maxDocs=44218)
                  0.0390625 = fieldNorm(doc=1237)
          0.5 = coord(1/2)
        0.0051659266 = weight(_text_:a in 1237) [ClassicSimilarity], result of:
          0.0051659266 = score(doc=1237,freq=14.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.1685276 = fieldWeight in 1237, product of:
              3.7416575 = tf(freq=14.0), with freq of:
                14.0 = termFreq=14.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.0390625 = fieldNorm(doc=1237)
        0.0017360178 = weight(_text_:s in 1237) [ClassicSimilarity], result of:
          0.0017360178 = score(doc=1237,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.060061958 = fieldWeight in 1237, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.0390625 = fieldNorm(doc=1237)
      0.27272728 = coord(3/11)
    
    Abstract
    The h-index provides us with 9 natural classes which can be written as a matrix of 3 vectors. The 3 vectors are: X = (X1, X2, X3) and indicates publication distribution in the h-core, the h-tail, and the uncited ones, respectively; Y = (Y1, Y2, Y3) denotes the citation distribution of the h-core, the h-tail and the so-called "excess" citations (above the h-threshold), respectively; and Z = (Z1, Z2, Z3) = (Y1-X1, Y2-X2, Y3-X3). The matrix V = (X,Y,Z)T constructs a measure of academic performance, in which the 9 numbers can all be provided with meanings in different dimensions. The "academic trace" tr(V) of this matrix follows naturally, and contributes a unique indicator for total academic achievements by summarizing and weighting the accumulation of publications and citations. This measure can also be used to combine the advantages of the h-index and the integrated impact indicator (I3) into a single number with a meaningful interpretation of the values. We illustrate the use of tr(V) for the cases of 2 journal sets, 2 universities, and ourselves as 2 individual authors.
    Object
    h-index
    Source
    Journal of the Association for Information Science and Technology. 65(2014) no.4, S.742-750
    Type
    a
  9. Leydesdorff, L.; Sun, Y.: National and international dimensions of the Triple Helix in Japan : university-industry-government versus international coauthorship relations (2009) 0.01
    0.00508037 = product of:
      0.018628024 = sum of:
        0.0057392623 = weight(_text_:a in 2761) [ClassicSimilarity], result of:
          0.0057392623 = score(doc=2761,freq=12.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.18723148 = fieldWeight in 2761, product of:
              3.4641016 = tf(freq=12.0), with freq of:
                12.0 = termFreq=12.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.046875 = fieldNorm(doc=2761)
        0.0020832212 = weight(_text_:s in 2761) [ClassicSimilarity], result of:
          0.0020832212 = score(doc=2761,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.072074346 = fieldWeight in 2761, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.046875 = fieldNorm(doc=2761)
        0.010805541 = product of:
          0.021611081 = sum of:
            0.021611081 = weight(_text_:22 in 2761) [ClassicSimilarity], result of:
              0.021611081 = score(doc=2761,freq=2.0), product of:
                0.09309476 = queryWeight, product of:
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.026584605 = queryNorm
                0.23214069 = fieldWeight in 2761, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.046875 = fieldNorm(doc=2761)
          0.5 = coord(1/2)
      0.27272728 = coord(3/11)
    
    Abstract
    International co-authorship relations and university-industry-government (Triple Helix) relations have hitherto been studied separately. Using Japanese publication data for the 1981-2004 period, we were able to study both kinds of relations in a single design. In the Japanese file, 1,277,030 articles with at least one Japanese address were attributed to the three sectors, and we know additionally whether these papers were coauthored internationally. Using the mutual information in three and four dimensions, respectively, we show that the Japanese Triple-Helix system has been continuously eroded at the national level. However, since the mid-1990s, international coauthorship relations have contributed to a reduction of the uncertainty at the national level. In other words, the national publication system of Japan has developed a capacity to retain surplus value generated internationally. In a final section, we compare these results with an analysis based on similar data for Canada. A relative uncoupling of national university-industry-government relations because of international collaborations is indicated in both countries.
    Date
    22. 3.2009 19:07:20
    Source
    Journal of the American Society for Information Science and Technology. 60(2009) no.4, S.778-788
    Type
    a
  10. Leydesdorff, L.; Johnson, M.W.; Ivanova, I.: Toward a calculus of redundancy : signification, codification, and anticipation in cultural evolution (2018) 0.00
    0.0046132086 = product of:
      0.016915098 = sum of:
        0.0061744633 = weight(_text_:a in 4463) [ClassicSimilarity], result of:
          0.0061744633 = score(doc=4463,freq=20.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.20142901 = fieldWeight in 4463, product of:
              4.472136 = tf(freq=20.0), with freq of:
                20.0 = termFreq=20.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.0390625 = fieldNorm(doc=4463)
        0.0017360178 = weight(_text_:s in 4463) [ClassicSimilarity], result of:
          0.0017360178 = score(doc=4463,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.060061958 = fieldWeight in 4463, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.0390625 = fieldNorm(doc=4463)
        0.009004618 = product of:
          0.018009236 = sum of:
            0.018009236 = weight(_text_:22 in 4463) [ClassicSimilarity], result of:
              0.018009236 = score(doc=4463,freq=2.0), product of:
                0.09309476 = queryWeight, product of:
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.026584605 = queryNorm
                0.19345059 = fieldWeight in 4463, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.0390625 = fieldNorm(doc=4463)
          0.5 = coord(1/2)
      0.27272728 = coord(3/11)
    
    Abstract
    This article considers the relationships among meaning generation, selection, and the dynamics of discourse from a variety of perspectives ranging from information theory and biology to sociology. Following Husserl's idea of a horizon of meanings in intersubjective communication, we propose a way in which, using Shannon's equations, the generation and selection of meanings from a horizon of possibilities can be considered probabilistically. The information-theoretical dynamics we articulate considers a process of meaning generation within cultural evolution: information is imbued with meaning, and through this process, the number of options for the selection of meaning in discourse proliferates. The redundancy of possible meanings contributes to a codification of expectations within the discourse. Unlike hardwired DNA, the codes of nonbiological systems can coevolve with the variations. Spanning horizons of meaning, the codes structure the communications as selection environments that shape discourses. Discursive knowledge can be considered as meta-coded communication that enables us to translate among differently coded communications. The dynamics of discursive knowledge production can thus infuse the historical dynamics with a cultural evolution by adding options, that is, by increasing redundancy. A calculus of redundancy is presented as an indicator whereby these dynamics of discourse and meaning may be explored empirically.
    Date
    29. 9.2018 11:22:09
    Source
    Journal of the Association for Information Science and Technology. 69(2018) no.10, S.1181-1192
    Type
    a
  11. Leydesdorff, L.; Persson, O.: Mapping the geography of science : distribution patterns and networks of relations among cities and institutes (2010) 0.00
    0.004496626 = product of:
      0.016487628 = sum of:
        0.0033135647 = weight(_text_:a in 3704) [ClassicSimilarity], result of:
          0.0033135647 = score(doc=3704,freq=4.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.10809815 = fieldWeight in 3704, 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=3704)
        0.011090843 = product of:
          0.044363372 = sum of:
            0.044363372 = weight(_text_:o in 3704) [ClassicSimilarity], result of:
              0.044363372 = score(doc=3704,freq=2.0), product of:
                0.13338262 = queryWeight, product of:
                  5.017288 = idf(docFreq=795, maxDocs=44218)
                  0.026584605 = queryNorm
                0.33260235 = fieldWeight in 3704, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  5.017288 = idf(docFreq=795, maxDocs=44218)
                  0.046875 = fieldNorm(doc=3704)
          0.25 = coord(1/4)
        0.0020832212 = weight(_text_:s in 3704) [ClassicSimilarity], result of:
          0.0020832212 = score(doc=3704,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.072074346 = fieldWeight in 3704, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.046875 = fieldNorm(doc=3704)
      0.27272728 = coord(3/11)
    
    Abstract
    Using Google Earth, Google Maps, and/or network visualization programs such as Pajek, one can overlay the network of relations among addresses in scientific publications onto the geographic map. The authors discuss the pros and cons of various options, and provide software (freeware) for bridging existing gaps between the Science Citation Indices (Thomson Reuters) and Scopus (Elsevier), on the one hand, and these various visualization tools on the other. At the level of city names, the global map can be drawn reliably on the basis of the available address information. At the level of the names of organizations and institutes, there are problems of unification both in the ISI databases and with Scopus. Pajek enables a combination of visualization and statistical analysis, whereas the Google Maps and its derivatives provide superior tools on the Internet.
    Source
    Journal of the American Society for Information Science and Technology. 61(2010) no.8, S.1622-1634
    Type
    a
  12. Leydesdorff, L.: Can networks of journal-journal citations be used as indicators of change in the social sciences? (2003) 0.00
    0.0044188164 = product of:
      0.016202327 = sum of:
        0.0033135647 = weight(_text_:a in 4460) [ClassicSimilarity], result of:
          0.0033135647 = score(doc=4460,freq=4.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.10809815 = fieldWeight in 4460, 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=4460)
        0.0020832212 = weight(_text_:s in 4460) [ClassicSimilarity], result of:
          0.0020832212 = score(doc=4460,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.072074346 = fieldWeight in 4460, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.046875 = fieldNorm(doc=4460)
        0.010805541 = product of:
          0.021611081 = sum of:
            0.021611081 = weight(_text_:22 in 4460) [ClassicSimilarity], result of:
              0.021611081 = score(doc=4460,freq=2.0), product of:
                0.09309476 = queryWeight, product of:
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.026584605 = queryNorm
                0.23214069 = fieldWeight in 4460, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.046875 = fieldNorm(doc=4460)
          0.5 = coord(1/2)
      0.27272728 = coord(3/11)
    
    Abstract
    Aggregated journal-journal citations can be used for mapping the intellectual organization of the sciences in terms of specialties because the latter can be considered as interreading communities. Can the journal-journal citations also be used as early indicators of change by comparing the files for two subsequent years? Probabilistic entropy measures enable us to analyze changes in large datasets at different levels of aggregation and in considerable detail. Compares Journal Citation Reports of the Social Science Citation Index for 1999 with similar data for 1998 and analyzes the differences using these measures. Compares the various indicators with similar developments in the Science Citation Index. Specialty formation seems a more important mechanism in the development of the social sciences than in the natural and life sciences, but the developments in the social sciences are volatile. The use of aggregate statistics based on the Science Citation Index is ill-advised in the case of the social sciences because of structural differences in the underlying dynamics.
    Date
    6.11.2005 19:02:22
    Source
    Journal of documentation. 59(2003) no.1, S.84-104
    Type
    a
  13. Hellsten, I.; Leydesdorff, L.: ¬The construction of interdisciplinarity : the development of the knowledge base and programmatic focus of the journal Climatic Change, 1977-2013 (2016) 0.00
    0.0042336425 = product of:
      0.015523355 = sum of:
        0.004782719 = weight(_text_:a in 3089) [ClassicSimilarity], result of:
          0.004782719 = score(doc=3089,freq=12.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.15602624 = fieldWeight in 3089, product of:
              3.4641016 = tf(freq=12.0), with freq of:
                12.0 = termFreq=12.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.0390625 = fieldNorm(doc=3089)
        0.0017360178 = weight(_text_:s in 3089) [ClassicSimilarity], result of:
          0.0017360178 = score(doc=3089,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.060061958 = fieldWeight in 3089, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.0390625 = fieldNorm(doc=3089)
        0.009004618 = product of:
          0.018009236 = sum of:
            0.018009236 = weight(_text_:22 in 3089) [ClassicSimilarity], result of:
              0.018009236 = score(doc=3089,freq=2.0), product of:
                0.09309476 = queryWeight, product of:
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.026584605 = queryNorm
                0.19345059 = fieldWeight in 3089, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.0390625 = fieldNorm(doc=3089)
          0.5 = coord(1/2)
      0.27272728 = coord(3/11)
    
    Abstract
    Climate change as a complex physical and social issue has gained increasing attention in the natural as well as the social sciences. Climate change research has become more interdisciplinary and even transdisciplinary as a typical Mode-2 science that is also dependent on an application context for its further development. We propose to approach interdisciplinarity as a co-construction of the knowledge base in the reference patterns and the programmatic focus in the editorials in the core journal of the climate-change sciences-Climatic Change-during the period 1977-2013. First, we analyze the knowledge base of the journal and map journal-journal relations on the basis of the references in the articles. Second, we follow the development of the programmatic focus by analyzing the semantics in the editorials. We argue that interdisciplinarity is a result of the co-construction between different agendas: The selection of publications into the knowledge base of the journal, and the adjustment of the programmatic focus to the political context in the editorials. Our results show a widening of the knowledge base from referencing the multidisciplinary journals Nature and Science to citing journals from specialist fields. The programmatic focus follows policy-oriented issues and incorporates public metaphors.
    Date
    24. 8.2016 17:53:22
    Source
    Journal of the Association for Information Science and Technology. 67(2016) no.9, S.2181-2193
    Type
    a
  14. Leydesdorff, L.; Bornmann, L.: How fractional counting of citations affects the impact factor : normalization in terms of differences in citation potentials among fields of science (2011) 0.00
    0.004119993 = product of:
      0.015106641 = sum of:
        0.0043660053 = weight(_text_:a in 4186) [ClassicSimilarity], result of:
          0.0043660053 = score(doc=4186,freq=10.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.14243183 = fieldWeight in 4186, product of:
              3.1622777 = tf(freq=10.0), with freq of:
                10.0 = termFreq=10.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.0390625 = fieldNorm(doc=4186)
        0.0017360178 = weight(_text_:s in 4186) [ClassicSimilarity], result of:
          0.0017360178 = score(doc=4186,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.060061958 = fieldWeight in 4186, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.0390625 = fieldNorm(doc=4186)
        0.009004618 = product of:
          0.018009236 = sum of:
            0.018009236 = weight(_text_:22 in 4186) [ClassicSimilarity], result of:
              0.018009236 = score(doc=4186,freq=2.0), product of:
                0.09309476 = queryWeight, product of:
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.026584605 = queryNorm
                0.19345059 = fieldWeight in 4186, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.0390625 = fieldNorm(doc=4186)
          0.5 = coord(1/2)
      0.27272728 = coord(3/11)
    
    Abstract
    The Impact Factors (IFs) of the Institute for Scientific Information suffer from a number of drawbacks, among them the statistics-Why should one use the mean and not the median?-and the incomparability among fields of science because of systematic differences in citation behavior among fields. Can these drawbacks be counteracted by fractionally counting citation weights instead of using whole numbers in the numerators? (a) Fractional citation counts are normalized in terms of the citing sources and thus would take into account differences in citation behavior among fields of science. (b) Differences in the resulting distributions can be tested statistically for their significance at different levels of aggregation. (c) Fractional counting can be generalized to any document set including journals or groups of journals, and thus the significance of differences among both small and large sets can be tested. A list of fractionally counted IFs for 2008 is available online at http:www.leydesdorff.net/weighted_if/weighted_if.xls The between-group variance among the 13 fields of science identified in the U.S. Science and Engineering Indicators is no longer statistically significant after this normalization. Although citation behavior differs largely between disciplines, the reflection of these differences in fractionally counted citation distributions can not be used as a reliable instrument for the classification.
    Date
    22. 1.2011 12:51:07
    Source
    Journal of the American Society for Information Science and Technology. 62(2011) no.2, S.217-229
    Type
    a
  15. Leydesdorff, L.: How are new citation-based journal indicators adding to the bibliometric toolbox? (2009) 0.00
    0.002690519 = product of:
      0.009865236 = sum of:
        0.0054389704 = product of:
          0.010877941 = sum of:
            0.010877941 = weight(_text_:h in 2929) [ClassicSimilarity], result of:
              0.010877941 = score(doc=2929,freq=2.0), product of:
                0.0660481 = queryWeight, product of:
                  2.4844491 = idf(docFreq=10020, maxDocs=44218)
                  0.026584605 = queryNorm
                0.16469726 = fieldWeight in 2929, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  2.4844491 = idf(docFreq=10020, maxDocs=44218)
                  0.046875 = fieldNorm(doc=2929)
          0.5 = coord(1/2)
        0.0023430442 = weight(_text_:a in 2929) [ClassicSimilarity], result of:
          0.0023430442 = score(doc=2929,freq=2.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.07643694 = fieldWeight in 2929, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.046875 = fieldNorm(doc=2929)
        0.0020832212 = weight(_text_:s in 2929) [ClassicSimilarity], result of:
          0.0020832212 = score(doc=2929,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.072074346 = fieldWeight in 2929, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.046875 = fieldNorm(doc=2929)
      0.27272728 = coord(3/11)
    
    Abstract
    The launching of Scopus and Google Scholar, and methodological developments in social-network analysis have made many more indicators for evaluating journals available than the traditional impact factor, cited half-life, and immediacy index of the ISI. In this study, these new indicators are compared with one another and with the older ones. Do the various indicators measure new dimensions of the citation networks, or are they highly correlated among themselves? Are they robust and relatively stable over time? Two main dimensions are distinguished - size and impact - which together shape influence. The h-index combines the two dimensions and can also be considered as an indicator of reach (like Indegree). PageRank is mainly an indicator of size, but has important interactions with centrality measures. The Scimago Journal Ranking (SJR) indicator provides an alternative to the journal impact factor, but the computation is less easy.
    Source
    Journal of the American Society for Information Science and Technology. 60(2009) no.7, S.1327-1336
    Type
    a
  16. Leydesdorff, L.: Should co-occurrence data be normalized : a rejoinder (2007) 0.00
    0.0019624678 = product of:
      0.010793572 = sum of:
        0.0066271294 = weight(_text_:a in 627) [ClassicSimilarity], result of:
          0.0066271294 = score(doc=627,freq=4.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.2161963 = fieldWeight in 627, product of:
              2.0 = tf(freq=4.0), with freq of:
                4.0 = termFreq=4.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.09375 = fieldNorm(doc=627)
        0.0041664424 = weight(_text_:s in 627) [ClassicSimilarity], result of:
          0.0041664424 = score(doc=627,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.14414869 = fieldWeight in 627, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.09375 = fieldNorm(doc=627)
      0.18181819 = coord(2/11)
    
    Source
    Journal of the American Society for Information Science and Technology. 58(2007) no.14, S.2411-2413
    Type
    a
  17. Bornmann, L.; Leydesdorff, L.: Statistical tests and research assessments : a comment on Schneider (2012) (2013) 0.00
    0.0019624678 = product of:
      0.010793572 = sum of:
        0.0066271294 = weight(_text_:a in 752) [ClassicSimilarity], result of:
          0.0066271294 = score(doc=752,freq=4.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.2161963 = fieldWeight in 752, product of:
              2.0 = tf(freq=4.0), with freq of:
                4.0 = termFreq=4.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.09375 = fieldNorm(doc=752)
        0.0041664424 = weight(_text_:s in 752) [ClassicSimilarity], result of:
          0.0041664424 = score(doc=752,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.14414869 = fieldWeight in 752, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.09375 = fieldNorm(doc=752)
      0.18181819 = coord(2/11)
    
    Source
    Journal of the American Society for Information Science and Technology. 64(2013) no.6, S.1306-1308
    Type
    a
  18. Leydesdorff, L.: Similarity measures, author cocitation Analysis, and information theory (2005) 0.00
    0.0016593148 = product of:
      0.009126231 = sum of:
        0.006695806 = weight(_text_:a in 3471) [ClassicSimilarity], result of:
          0.006695806 = score(doc=3471,freq=12.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.21843673 = fieldWeight in 3471, product of:
              3.4641016 = tf(freq=12.0), with freq of:
                12.0 = termFreq=12.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.0546875 = fieldNorm(doc=3471)
        0.0024304248 = weight(_text_:s in 3471) [ClassicSimilarity], result of:
          0.0024304248 = score(doc=3471,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.08408674 = fieldWeight in 3471, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.0546875 = fieldNorm(doc=3471)
      0.18181819 = coord(2/11)
    
    Abstract
    The use of Pearson's correlation coefficient in Author Cocitation Analysis was compared with Salton's cosine measure in a number of recent contributions. Unlike the Pearson correlation, the cosine is insensitive to the number of zeros. However, one has the option of applying a logarithmic transformation in correlation analysis. Information caiculus is based an both the logarithmic transformation and provides a non-parametric statistics. Using this methodology, one can cluster a document set in a precise way and express the differences in terms of bits of information. The algorithm is explained and used an the data set, which was made the subject of this discussion.
    Source
    Journal of the American Society for Information Science and Technology. 56(2005) no.7, S.769-772
    Type
    a
  19. Leydesdorff, L.: Accounting for the uncertainty in the evaluation of percentile ranks (2012) 0.00
    0.001609551 = product of:
      0.00885253 = sum of:
        0.0046860883 = weight(_text_:a in 447) [ClassicSimilarity], result of:
          0.0046860883 = score(doc=447,freq=2.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.15287387 = fieldWeight in 447, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.09375 = fieldNorm(doc=447)
        0.0041664424 = weight(_text_:s in 447) [ClassicSimilarity], result of:
          0.0041664424 = score(doc=447,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.14414869 = fieldWeight in 447, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.09375 = fieldNorm(doc=447)
      0.18181819 = coord(2/11)
    
    Source
    Journal of the American Society for Information Science and Technology. 63(2012) no.11, S.2349-2350
    Type
    a
  20. Leydesdorff, L.; Wagner, C,; Bornmann, L.: Replicability and the public/private divide (2016) 0.00
    0.001609551 = product of:
      0.00885253 = sum of:
        0.0046860883 = weight(_text_:a in 3023) [ClassicSimilarity], result of:
          0.0046860883 = score(doc=3023,freq=2.0), product of:
            0.030653298 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.026584605 = queryNorm
            0.15287387 = fieldWeight in 3023, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.09375 = fieldNorm(doc=3023)
        0.0041664424 = weight(_text_:s in 3023) [ClassicSimilarity], result of:
          0.0041664424 = score(doc=3023,freq=2.0), product of:
            0.028903782 = queryWeight, product of:
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.026584605 = queryNorm
            0.14414869 = fieldWeight in 3023, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              1.0872376 = idf(docFreq=40523, maxDocs=44218)
              0.09375 = fieldNorm(doc=3023)
      0.18181819 = coord(2/11)
    
    Source
    Journal of the Association for Information Science and Technology. 67(2016) no.7, S.1777-1778
    Type
    a