Search (52 results, page 1 of 3)

  • × year_i:[2010 TO 2020}
  • × author_ss:"Leydesdorff, L."
  1. Leydesdorff, L.; Bornmann, L.; Wagner, C.S.: ¬The relative influences of government funding and international collaboration on citation impact (2019) 0.02 
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    Date
    8. 1.2019 18:22:45
    Source
    Journal of the Association for Information Science and Technology. 70(2019) no.2, S.198-201
  2. 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) 0.02 
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    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
  3. 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) 0.02 
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    Date
    24. 8.2016 17:53:22
    Source
    Journal of the Association for Information Science and Technology. 67(2016) no.9, S.2181-2193
  4. Leydesdorff, L.; Johnson, M.W.; Ivanova, I.: Toward a calculus of redundancy : signification, codification, and anticipation in cultural evolution (2018) 0.02 
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    Date
    29. 9.2018 11:22:09
    Source
    Journal of the Association for Information Science and Technology. 69(2018) no.10, S.1181-1192
  5. Leydesdorff, L.: Accounting for the uncertainty in the evaluation of percentile ranks (2012) 0.00 
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    Source
    Journal of the American Society for Information Science and Technology. 63(2012) no.11, S.2349-2350
  6. Bornmann, L.; Leydesdorff, L.: Statistical tests and research assessments : a comment on Schneider (2012) (2013) 0.00 
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    Source
    Journal of the American Society for Information Science and Technology. 64(2013) no.6, S.1306-1308
  7. Leydesdorff, L.; Wagner, C,; Bornmann, L.: Replicability and the public/private divide (2016) 0.00 
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    Source
    Journal of the Association for Information Science and Technology. 67(2016) no.7, S.1777-1778
  8. Leydesdorff, L.; Strand, Oe.: ¬The Swedish system of innovation : regional synergies in a knowledge-based economy (2013) 0.00 
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    Location
    S
    Source
    Journal of the American Society for Information Science and Technology. 64(2013) no.9, S.1890-1902
  9. Leydesdorff, L.; Heimeriks, G.; Rotolo, D.: Journal portfolio analysis for countries, cities, and organizations : maps and comparisons (2016) 0.00 
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    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.
    Source
    Journal of the Association for Information Science and Technology. 67(2016) no.3, S.741-748
  10. Zhou, Q.; Leydesdorff, L.: ¬The normalization of occurrence and co-occurrence matrices in bibliometrics using Cosine similarities and Ochiai coefficients (2016) 0.00 
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    Abstract
    We prove that Ochiai similarity of the co-occurrence matrix is equal to cosine similarity in the underlying occurrence matrix. Neither the cosine nor the Pearson correlation should be used for the normalization of co-occurrence matrices because the similarity is then normalized twice, and therefore overestimated; the Ochiai coefficient can be used instead. Results are shown using a small matrix (5 cases, 4 variables) for didactic reasons, and also Ahlgren et?al.'s (2003) co-occurrence matrix of 24 authors in library and information sciences. The overestimation is shown numerically and will be illustrated using multidimensional scaling and cluster dendograms. If the occurrence matrix is not available (such as in internet research or author cocitation analysis) using Ochiai for the normalization is preferable to using the cosine.
    Source
    Journal of the Association for Information Science and Technology. 67(2016) no.11, S.2805-2814
  11. Leydesdorff, L.; Shin, J.C.: How to evaluate universities in terms of their relative citation impacts : fractional counting of citations and the normalization of differences among disciplines (2011) 0.00 
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    Journal of the American Society for Information Science and Technology. 62(2011) no.6, S.1146-1155
  12. Marx, W.; Bornmann, L.; Barth, A.; Leydesdorff, L.: Detecting the historical roots of research fields by reference publication year spectroscopy (RPYS) (2014) 0.00 
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    Journal of the Association for Information Science and Technology. 65(2014) no.4, S.751-764
  13. 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 
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    Journal of the American Society for Information Science and Technology. 61(2010) no.4, S.787-801
  14. Zhou, P.; Su, X.; Leydesdorff, L.: ¬A comparative study on communication structures of Chinese journals in the social sciences (2010) 0.00 
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    Journal of the American Society for Information Science and Technology. 61(2010) no.7, S.1360-1376
  15. Leydesdorff, L.; Persson, O.: Mapping the geography of science : distribution patterns and networks of relations among cities and institutes (2010) 0.00 
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    Journal of the American Society for Information Science and Technology. 61(2010) no.8, S.1622-1634
  16. Rafols, I.; Porter, A.L.; Leydesdorff, L.: Science overlay maps : a new tool for research policy and library management (2010) 0.00 
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    Journal of the American Society for Information Science and Technology. 61(2010) no.9, S.1871-1887
  17. Leydesdorff, L.: ¬The communication of meaning and the structuration of expectations : Giddens' "structuration theory" and Luhmann's "self-organization" (2010) 0.00 
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    Journal of the American Society for Information Science and Technology. 61(2010) no.10, S.2138-2150
  18. Leydesdorff, L.; Opthof, T.: Scopus's source normalized impact per paper (SNIP) versus a journal impact factor based on fractional counting of citations (2010) 0.00 
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    Journal of the American Society for Information Science and Technology. 61(2010) no.11, S.2365-2369
  19. Leydesdorff, L.; Rafols, I.: Local emergence and global diffusion of research technologies : an exploration of patterns of network formation (2011) 0.00 
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    Journal of the American Society for Information Science and Technology. 62(2011) no.5, S.846-860
  20. Leydesdorff, L.; Bornmann, L.; Mutz, R.; Opthof, T.: Turning the tables on citation analysis one more time : principles for comparing sets of documents (2011) 0.00 
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    Source
    Journal of the American Society for Information Science and Technology. 62(2011) no.7, S.1370-1381

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