Search (87 results, page 1 of 5)

  • × author_ss:"Leydesdorff, L."
  1. 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) 0.04
    0.04008572 = product of:
      0.09353335 = sum of:
        0.048994634 = weight(_text_:g in 1110) [ClassicSimilarity], result of:
          0.048994634 = score(doc=1110,freq=4.0), product of:
            0.13914184 = queryWeight, product of:
              3.7559474 = idf(docFreq=2809, maxDocs=44218)
              0.03704574 = queryNorm
            0.35212007 = fieldWeight in 1110, product of:
              2.0 = tf(freq=4.0), with freq of:
                4.0 = termFreq=4.0
              3.7559474 = idf(docFreq=2809, maxDocs=44218)
              0.046875 = fieldNorm(doc=1110)
        0.037237864 = weight(_text_:u in 1110) [ClassicSimilarity], result of:
          0.037237864 = score(doc=1110,freq=4.0), product of:
            0.121304214 = queryWeight, product of:
              3.2744443 = idf(docFreq=4547, maxDocs=44218)
              0.03704574 = 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)
        0.007300853 = weight(_text_:a in 1110) [ClassicSimilarity], result of:
          0.007300853 = score(doc=1110,freq=10.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = 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)
      0.42857143 = coord(3/7)
    
    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.
    Type
    a
  2. Leydesdorff, L.; Heimeriks, G.: ¬The self-organization of the European information society : the case of "biotechnology" (2001) 0.02
    0.020062016 = product of:
      0.046811372 = sum of:
        0.013228328 = product of:
          0.026456656 = sum of:
            0.026456656 = weight(_text_:p in 6524) [ClassicSimilarity], result of:
              0.026456656 = score(doc=6524,freq=2.0), product of:
                0.13319843 = queryWeight, product of:
                  3.5955126 = idf(docFreq=3298, maxDocs=44218)
                  0.03704574 = queryNorm
                0.19862589 = fieldWeight in 6524, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5955126 = idf(docFreq=3298, maxDocs=44218)
                  0.0390625 = fieldNorm(doc=6524)
          0.5 = coord(1/2)
        0.028870367 = weight(_text_:g in 6524) [ClassicSimilarity], result of:
          0.028870367 = score(doc=6524,freq=2.0), product of:
            0.13914184 = queryWeight, product of:
              3.7559474 = idf(docFreq=2809, maxDocs=44218)
              0.03704574 = queryNorm
            0.20748875 = fieldWeight in 6524, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              3.7559474 = idf(docFreq=2809, maxDocs=44218)
              0.0390625 = fieldNorm(doc=6524)
        0.00471268 = weight(_text_:a in 6524) [ClassicSimilarity], result of:
          0.00471268 = score(doc=6524,freq=6.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = queryNorm
            0.11032722 = fieldWeight in 6524, 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=6524)
      0.42857143 = coord(3/7)
    
    Abstract
    Fields of technoscience like biotechnology develop in a network mode: disciplinary insights from different backgrounds are recombined as competing innovation systems are continuously reshaped. The ongoing process of integration at the European level generates an additional network of transnational collaborations. Using the title words of scientific publications in five core journals of biotechnology, multivariate analysis is used to distinguish between the intellectual organization of the publications in terms of title words and the institutional network in terms of addresses of documents. The interaction among the representation of intellectual space in terms of words and co-words, and the potentially European network system is compared with the document sets with American and Japanese addresses. The European system can also be decomposed in terms of the contributions of member states. Whereas a European vocabulary can be made visible at the global level, this communality disappears by this decomposition. The network effect at the European level can be considered as institutional more than cognitive
    Footnote
    Vgl. auch die Stellungnahme von P. van den Besselaar: Empirical evidence of self-organization? in: JASIST 54(2003) no.1, S.87-90.
    Type
    a
  3. Leydesdorff, L.; Heimeriks, G.; Rotolo, D.: Journal portfolio analysis for countries, cities, and organizations : maps and comparisons (2016) 0.01
    0.011764149 = product of:
      0.04117452 = sum of:
        0.03464444 = weight(_text_:g in 2781) [ClassicSimilarity], result of:
          0.03464444 = score(doc=2781,freq=2.0), product of:
            0.13914184 = queryWeight, product of:
              3.7559474 = idf(docFreq=2809, maxDocs=44218)
              0.03704574 = queryNorm
            0.24898648 = fieldWeight in 2781, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              3.7559474 = idf(docFreq=2809, maxDocs=44218)
              0.046875 = fieldNorm(doc=2781)
        0.006530081 = weight(_text_:a in 2781) [ClassicSimilarity], result of:
          0.006530081 = score(doc=2781,freq=8.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = queryNorm
            0.15287387 = fieldWeight in 2781, 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=2781)
      0.2857143 = coord(2/7)
    
    Abstract
    Using Web of Science data, portfolio analysis in terms of journal coverage can be projected onto a base map for units of analysis such as countries, cities, universities, and firms. The units of analysis under study can be compared statistically across the 10,000+ journals. The interdisciplinarity of the portfolios is measured using Rao-Stirling diversity or Zhang et?al.'s improved measure 2D3. At the country level we find regional differentiation (e.g., Latin American or Asian countries), but also a major divide between advanced and less-developed countries. Israel and Israeli cities outperform other nations and cities in terms of diversity. Universities appear to be specifically related to firms when a number of these units are exploratively compared. The instrument is relatively simple and straightforward, and one can generalize the application to any document set retrieved from the Web of Science (WoS). Further instruction is provided online at http://www.leydesdorff.net/portfolio.
    Type
    a
  4. Leydesdorff, L.; Zhou, P.: Co-word analysis using the Chinese character set (2008) 0.01
    0.006830486 = product of:
      0.0239067 = sum of:
        0.018519659 = product of:
          0.037039317 = sum of:
            0.037039317 = weight(_text_:p in 1970) [ClassicSimilarity], result of:
              0.037039317 = score(doc=1970,freq=2.0), product of:
                0.13319843 = queryWeight, product of:
                  3.5955126 = idf(docFreq=3298, maxDocs=44218)
                  0.03704574 = queryNorm
                0.27807623 = fieldWeight in 1970, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5955126 = idf(docFreq=3298, maxDocs=44218)
                  0.0546875 = fieldNorm(doc=1970)
          0.5 = coord(1/2)
        0.005387042 = weight(_text_:a in 1970) [ClassicSimilarity], result of:
          0.005387042 = score(doc=1970,freq=4.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = queryNorm
            0.12611452 = fieldWeight in 1970, 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=1970)
      0.2857143 = coord(2/7)
    
    Abstract
    Until recently, Chinese texts could not be studied using co-word analysis because the words are not separated by spaces in Chinese (and Japanese). A word can be composed of one or more characters. The online availability of programs that separate Chinese texts makes it possible to analyze them using semantic maps. Chinese characters contain not only information but also meaning. This may enhance the readability of semantic maps. In this study, we analyze 58 words which occur 10 or more times in the 1,652 journal titles of the China Scientific and Technical Papers and Citations Database. The word-occurrence matrix is visualized and factor-analyzed.
    Type
    a
  5. Leydesdorff, L.: ¬The construction and globalization of the knowledge base in inter-human communication systems (2003) 0.01
    0.006587212 = product of:
      0.02305524 = sum of:
        0.007997682 = weight(_text_:a in 1621) [ClassicSimilarity], result of:
          0.007997682 = score(doc=1621,freq=12.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = 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)
        0.015057558 = product of:
          0.030115116 = sum of:
            0.030115116 = weight(_text_:22 in 1621) [ClassicSimilarity], result of:
              0.030115116 = score(doc=1621,freq=2.0), product of:
                0.12972787 = queryWeight, product of:
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.03704574 = 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)
      0.2857143 = coord(2/7)
    
    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
    Type
    a
  6. Leydesdorff, L.; Sun, Y.: National and international dimensions of the Triple Helix in Japan : university-industry-government versus international coauthorship relations (2009) 0.01
    0.006587212 = product of:
      0.02305524 = sum of:
        0.007997682 = weight(_text_:a in 2761) [ClassicSimilarity], result of:
          0.007997682 = score(doc=2761,freq=12.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = 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)
        0.015057558 = product of:
          0.030115116 = sum of:
            0.030115116 = weight(_text_:22 in 2761) [ClassicSimilarity], result of:
              0.030115116 = score(doc=2761,freq=2.0), product of:
                0.12972787 = queryWeight, product of:
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.03704574 = 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)
      0.2857143 = coord(2/7)
    
    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
    Type
    a
  7. Leydesdorff, L.; Ahrweiler, P.: In search of a network theory of innovations : relations, positions, and perspectives (2014) 0.01
    0.0064724823 = product of:
      0.022653688 = sum of:
        0.013228328 = product of:
          0.026456656 = sum of:
            0.026456656 = weight(_text_:p in 1531) [ClassicSimilarity], result of:
              0.026456656 = score(doc=1531,freq=2.0), product of:
                0.13319843 = queryWeight, product of:
                  3.5955126 = idf(docFreq=3298, maxDocs=44218)
                  0.03704574 = queryNorm
                0.19862589 = fieldWeight in 1531, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5955126 = idf(docFreq=3298, maxDocs=44218)
                  0.0390625 = fieldNorm(doc=1531)
          0.5 = coord(1/2)
        0.00942536 = weight(_text_:a in 1531) [ClassicSimilarity], result of:
          0.00942536 = score(doc=1531,freq=24.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = queryNorm
            0.22065444 = fieldWeight in 1531, product of:
              4.8989797 = tf(freq=24.0), with freq of:
                24.0 = termFreq=24.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.0390625 = fieldNorm(doc=1531)
      0.2857143 = coord(2/7)
    
    Abstract
    As a complement to Nelson and Winter's (1977) article titled "In Search of a Useful Theory of Innovation," a sociological perspective on innovation networks can be elaborated using Luhmann's social systems theory, on the one hand, and Latour's "sociology of translations," on the other. Because of a common focus on communication, these perspectives can be combined as a set of methodologies. Latour's sociology of translations specifies a mechanism for generating variation in relations ("associations"), whereas Luhmann's systems perspective enables the specification of (functionally different) selection environments such as markets, professional organizations, and political control. Selection environments can be considered as mechanisms of social coordination that can self-organize-beyond the control of human agency-into regimes in terms of interacting codes of communication. Unlike relatively globalized regimes, technological trajectories are organized locally in "landscapes." A resulting "duality of structure" (Giddens, 1979) between the historical organization of trajectories and evolutionary self-organization at the regime level can be expected to drive innovation cycles. Reflexive translations add a third layer of perspectives to (a) the relational analysis of observable links that shape trajectories and (b) the positional analysis of networks in terms of latent dimensions. These three operations can be studied in a single framework, but using different methodologies. Latour's first-order associations can then be analytically distinguished from second-order translations in terms of requiring other communicative competencies. The resulting operations remain infrareflexively nested, and can therefore be used for innovative reconstructions of previously constructed boundaries.
    Type
    a
  8. Leydesdorff, L.; Bornmann, L.; Wagner, C.S.: ¬The relative influences of government funding and international collaboration on citation impact (2019) 0.01
    0.0063881176 = product of:
      0.02235841 = sum of:
        0.007300853 = weight(_text_:a in 4681) [ClassicSimilarity], result of:
          0.007300853 = score(doc=4681,freq=10.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = 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)
        0.015057558 = product of:
          0.030115116 = sum of:
            0.030115116 = weight(_text_:22 in 4681) [ClassicSimilarity], result of:
              0.030115116 = score(doc=4681,freq=2.0), product of:
                0.12972787 = queryWeight, product of:
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.03704574 = 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)
      0.2857143 = coord(2/7)
    
    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
    Type
    a
  9. Zhou, P.; Leydesdorff, L.: ¬A comparison between the China Scientific and Technical Papers and Citations Database and the Science Citation Index in terms of journal hierarchies and interjournal citation relations (2007) 0.01
    0.0061512026 = product of:
      0.021529209 = sum of:
        0.015873993 = product of:
          0.031747986 = sum of:
            0.031747986 = weight(_text_:p in 70) [ClassicSimilarity], result of:
              0.031747986 = score(doc=70,freq=2.0), product of:
                0.13319843 = queryWeight, product of:
                  3.5955126 = idf(docFreq=3298, maxDocs=44218)
                  0.03704574 = queryNorm
                0.23835106 = fieldWeight in 70, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5955126 = idf(docFreq=3298, maxDocs=44218)
                  0.046875 = fieldNorm(doc=70)
          0.5 = coord(1/2)
        0.005655216 = weight(_text_:a in 70) [ClassicSimilarity], result of:
          0.005655216 = score(doc=70,freq=6.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = queryNorm
            0.13239266 = fieldWeight in 70, 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=70)
      0.2857143 = coord(2/7)
    
    Abstract
    The journal structure in the China Scientific and Technical Papers and Citations Database (CSTPCD) is analyzed from three perspectives: the database level, the specialty level, and the institutional level (i.e., university journals vs. journals issued by the Chinese Academy of Sciences). The results are compared with those for (Chinese) journals included in the Science Citation Index (SCI). The frequency of journal-journal citation relations in the CSTPCD is an order of magnitude lower than in the SCI. Chinese journals, especially high-quality journals, prefer to cite international journals rather than domestic ones; however, Chinese journals do not get an equivalent reception from their international counterparts. The international visibility of Chinese journals is low, but varies among fields of science. Journals of the Chinese Academy of Sciences have a better reception in the international scientific community than university journals.
    Type
    a
  10. Leydesdorff, L.; Johnson, M.W.; Ivanova, I.: Toward a calculus of redundancy : signification, codification, and anticipation in cultural evolution (2018) 0.01
    0.006043458 = product of:
      0.021152101 = sum of:
        0.008604136 = weight(_text_:a in 4463) [ClassicSimilarity], result of:
          0.008604136 = score(doc=4463,freq=20.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = 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)
        0.012547966 = product of:
          0.025095932 = sum of:
            0.025095932 = weight(_text_:22 in 4463) [ClassicSimilarity], result of:
              0.025095932 = score(doc=4463,freq=2.0), product of:
                0.12972787 = queryWeight, product of:
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.03704574 = 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)
      0.2857143 = coord(2/7)
    
    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
    Type
    a
  11. Zhou, P.; Su, X.; Leydesdorff, L.: ¬A comparative study on communication structures of Chinese journals in the social sciences (2010) 0.01
    0.005854702 = product of:
      0.020491457 = sum of:
        0.015873993 = product of:
          0.031747986 = sum of:
            0.031747986 = weight(_text_:p in 3580) [ClassicSimilarity], result of:
              0.031747986 = score(doc=3580,freq=2.0), product of:
                0.13319843 = queryWeight, product of:
                  3.5955126 = idf(docFreq=3298, maxDocs=44218)
                  0.03704574 = queryNorm
                0.23835106 = fieldWeight in 3580, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5955126 = idf(docFreq=3298, maxDocs=44218)
                  0.046875 = fieldNorm(doc=3580)
          0.5 = coord(1/2)
        0.0046174643 = weight(_text_:a in 3580) [ClassicSimilarity], result of:
          0.0046174643 = score(doc=3580,freq=4.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = queryNorm
            0.10809815 = fieldWeight in 3580, 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=3580)
      0.2857143 = coord(2/7)
    
    Type
    a
  12. Leydesdorff, L.: Can networks of journal-journal citations be used as indicators of change in the social sciences? (2003) 0.01
    0.005621435 = product of:
      0.019675022 = sum of:
        0.0046174643 = weight(_text_:a in 4460) [ClassicSimilarity], result of:
          0.0046174643 = score(doc=4460,freq=4.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = 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)
        0.015057558 = product of:
          0.030115116 = sum of:
            0.030115116 = weight(_text_:22 in 4460) [ClassicSimilarity], result of:
              0.030115116 = score(doc=4460,freq=2.0), product of:
                0.12972787 = queryWeight, product of:
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.03704574 = 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)
      0.2857143 = coord(2/7)
    
    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
    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) 0.01
    0.005489344 = product of:
      0.019212702 = sum of:
        0.0066647357 = weight(_text_:a in 3089) [ClassicSimilarity], result of:
          0.0066647357 = score(doc=3089,freq=12.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = 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)
        0.012547966 = product of:
          0.025095932 = sum of:
            0.025095932 = weight(_text_:22 in 3089) [ClassicSimilarity], result of:
              0.025095932 = score(doc=3089,freq=2.0), product of:
                0.12972787 = queryWeight, product of:
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.03704574 = 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)
      0.2857143 = coord(2/7)
    
    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
    Type
    a
  14. Leydesdorff, L.; Zhou, P.; Bornmann, L.: How can journal impact factors be normalized across fields of science? : An assessment in terms of percentile ranks and fractional counts (2013) 0.01
    0.0053343037 = product of:
      0.018670062 = sum of:
        0.013228328 = product of:
          0.026456656 = sum of:
            0.026456656 = weight(_text_:p in 532) [ClassicSimilarity], result of:
              0.026456656 = score(doc=532,freq=2.0), product of:
                0.13319843 = queryWeight, product of:
                  3.5955126 = idf(docFreq=3298, maxDocs=44218)
                  0.03704574 = queryNorm
                0.19862589 = fieldWeight in 532, product of:
                  1.4142135 = tf(freq=2.0), with freq of:
                    2.0 = termFreq=2.0
                  3.5955126 = idf(docFreq=3298, maxDocs=44218)
                  0.0390625 = fieldNorm(doc=532)
          0.5 = coord(1/2)
        0.0054417336 = weight(_text_:a in 532) [ClassicSimilarity], result of:
          0.0054417336 = score(doc=532,freq=8.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = queryNorm
            0.12739488 = fieldWeight in 532, product of:
              2.828427 = tf(freq=8.0), with freq of:
                8.0 = termFreq=8.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.0390625 = fieldNorm(doc=532)
      0.2857143 = coord(2/7)
    
    Abstract
    Using the CD-ROM version of the Science Citation Index 2010 (N = 3,705 journals), we study the (combined) effects of (a) fractional counting on the impact factor (IF) and (b) transformation of the skewed citation distributions into a distribution of 100 percentiles and six percentile rank classes (top-1%, top-5%, etc.). Do these approaches lead to field-normalized impact measures for journals? In addition to the 2-year IF (IF2), we consider the 5-year IF (IF5), the respective numerators of these IFs, and the number of Total Cites, counted both as integers and fractionally. These various indicators are tested against the hypothesis that the classification of journals into 11 broad fields by PatentBoard/NSF (National Science Foundation) provides statistically significant between-field effects. Using fractional counting the between-field variance is reduced by 91.7% in the case of IF5, and by 79.2% in the case of IF2. However, the differences in citation counts are not significantly affected by fractional counting. These results accord with previous studies, but the longer citation window of a fractionally counted IF5 can lead to significant improvement in the normalization across fields.
    Type
    a
  15. 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) 0.01
    0.0053234315 = product of:
      0.01863201 = sum of:
        0.0060840435 = weight(_text_:a in 4186) [ClassicSimilarity], result of:
          0.0060840435 = score(doc=4186,freq=10.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = 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)
        0.012547966 = product of:
          0.025095932 = sum of:
            0.025095932 = weight(_text_:22 in 4186) [ClassicSimilarity], result of:
              0.025095932 = score(doc=4186,freq=2.0), product of:
                0.12972787 = queryWeight, product of:
                  3.5018296 = idf(docFreq=3622, maxDocs=44218)
                  0.03704574 = 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)
      0.2857143 = coord(2/7)
    
    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
    Type
    a
  16. Chen, C.; Leydesdorff, L.: Patterns of connections and movements in dual-map overlays : a new method of publication portfolio analysis (2014) 0.00
    0.00134648 = product of:
      0.00942536 = sum of:
        0.00942536 = weight(_text_:a in 1200) [ClassicSimilarity], result of:
          0.00942536 = score(doc=1200,freq=24.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = queryNorm
            0.22065444 = fieldWeight in 1200, product of:
              4.8989797 = tf(freq=24.0), with freq of:
                24.0 = termFreq=24.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.0390625 = fieldNorm(doc=1200)
      0.14285715 = coord(1/7)
    
    Abstract
    Portfolio analysis of the publication profile of a unit of interest, ranging from individuals and organizations to a scientific field or interdisciplinary programs, aims to inform analysts and decision makers about the position of the unit, where it has been, and where it may go in a complex adaptive environment. A portfolio analysis may aim to identify the gap between the current position of an organization and a goal that it intends to achieve or identify competencies of multiple institutions. We introduce a new visual analytic method for analyzing, comparing, and contrasting characteristics of publication portfolios. The new method introduces a novel design of dual-map thematic overlays on global maps of science. Each publication portfolio can be added as one layer of dual-map overlays over 2 related, but distinct, global maps of science: one for citing journals and the other for cited journals. We demonstrate how the new design facilitates a portfolio analysis in terms of patterns emerging from the distributions of citation threads and the dynamics of trajectories as a function of space and time. We first demonstrate the analysis of portfolios defined on a single source article. Then we contrast publication portfolios of multiple comparable units of interest; namely, colleges in universities and corporate research organizations. We also include examples of overlays of scientific fields. We expect that our method will provide new insights to portfolio analysis.
    Type
    a
  17. Leydesdorff, L.: Similarity measures, author cocitation Analysis, and information theory (2005) 0.00
    0.0013329472 = product of:
      0.009330629 = sum of:
        0.009330629 = weight(_text_:a in 3471) [ClassicSimilarity], result of:
          0.009330629 = score(doc=3471,freq=12.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = 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)
      0.14285715 = coord(1/7)
    
    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.
    Type
    a
  18. Leydesdorff, L.: Should co-occurrence data be normalized : a rejoinder (2007) 0.00
    0.0013192756 = product of:
      0.0092349285 = sum of:
        0.0092349285 = weight(_text_:a in 627) [ClassicSimilarity], result of:
          0.0092349285 = score(doc=627,freq=4.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = 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)
      0.14285715 = coord(1/7)
    
    Type
    a
  19. Leydesdorff, L.; Salah, A.A.A.: Maps on the basis of the Arts & Humanities Citation Index : the journals Leonardo and Art Journal versus "digital humanities" as a topic (2010) 0.00
    0.0013192756 = product of:
      0.0092349285 = sum of:
        0.0092349285 = weight(_text_:a in 3436) [ClassicSimilarity], result of:
          0.0092349285 = score(doc=3436,freq=16.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = queryNorm
            0.2161963 = fieldWeight in 3436, product of:
              4.0 = tf(freq=16.0), with freq of:
                16.0 = termFreq=16.0
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.046875 = fieldNorm(doc=3436)
      0.14285715 = coord(1/7)
    
    Abstract
    The possibilities of using the Arts & Humanities Citation Index (A&HCI) for journal mapping have not been sufficiently recognized because of the absence of a Journal Citations Report (JCR) for this database. A quasi-JCR for the A&HCI ([2008]) was constructed from the data contained in the Web of Science and is used for the evaluation of two journals as examples: Leonardo and Art Journal. The maps on the basis of the aggregated journal-journal citations within this domain can be compared with maps including references to journals in the Science Citation Index and Social Science Citation Index. Art journals are cited by (social) science journals more than by other art journals, but these journals draw upon one another in terms of their own references. This cultural impact in terms of being cited is not found when documents with a topic such as digital humanities are analyzed. This community of practice functions more as an intellectual organizer than a journal.
    Type
    a
  20. Bornmann, L.; Leydesdorff, L.: Statistical tests and research assessments : a comment on Schneider (2012) (2013) 0.00
    0.0013192756 = product of:
      0.0092349285 = sum of:
        0.0092349285 = weight(_text_:a in 752) [ClassicSimilarity], result of:
          0.0092349285 = score(doc=752,freq=4.0), product of:
            0.04271548 = queryWeight, product of:
              1.153047 = idf(docFreq=37942, maxDocs=44218)
              0.03704574 = 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)
      0.14285715 = coord(1/7)
    
    Type
    a