Search (37 results, page 1 of 2)

  • × author_ss:"Leydesdorff, L."
  • × theme_ss:"Informetrie"
  • × year_i:[2010 TO 2020}
  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. 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
  4. 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
  5. 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
  6. 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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    Source
    Journal of the American Society for Information Science and Technology. 62(2011) no.6, S.1146-1155
  7. 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
  8. 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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    Source
    Journal of the American Society for Information Science and Technology. 61(2010) no.4, S.787-801
  9. 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
  10. 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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    Source
    Journal of the American Society for Information Science and Technology. 61(2010) no.11, S.2365-2369
  11. Bornmann, L.; Leydesdorff, L.: Which cities produce more excellent papers than can be expected? : a new mapping approach, using Google Maps, based on statistical significance testing (2011) 0.00 
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    Journal of the American Society for Information Science and Technology. 62(2011) no.10, S.1954-1962
  12. Leydesdorff, L.; Rotolo, D.; Rafols, I.: Bibliometric perspectives on medical innovation using the medical subject headings of PubMed (2012) 0.00 
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    Journal of the American Society for Information Science and Technology. 63(2012) no.11, S.2239-2253
  13. Leydesdorff, L.; Opthof, T.: Citation analysis with medical subject Headings (MeSH) using the Web of Knowledge : a new routine (2013) 0.00 
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    Journal of the American Society for Information Science and Technology. 64(2013) no.5, S.1076-1080
  14. Leydesdorff, L.; Radicchi, F.; Bornmann, L.; Castellano, C.; Nooy, W. de: Field-normalized impact factors (IFs) : a comparison of rescaling and fractionally counted IFs (2013) 0.00 
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    Journal of the American Society for Information Science and Technology. 64(2013) no.11, S.2299-2309
  15. 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) 0.00 
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    Journal of the American Society for Information Science and Technology. 64(2013) no.11, S.2317-2325
  16. Leydesdorff, L.; Goldstone, R.L.: Interdisciplinarity at the journal and specialty level : the changing knowledge bases of the journal cognitive science (2014) 0.00 
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    Journal of the Association for Information Science and Technology. 65(2014) no.1, S.164-177
  17. Rotolo, D.; Leydesdorff, L.: Matching Medline/PubMed data with Web of Science: A routine in R language (2015) 0.00 
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    Journal of the Association for Information Science and Technology. 66(2015) no.10, S.2155-2159
  18. Leydesdorff, L.; Bornmann, L.: ¬The operationalization of "fields" as WoS subject categories (WCs) in evaluative bibliometrics : the cases of "library and information science" and "science & technology studies" (2016) 0.00 
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    Journal of the Association for Information Science and Technology. 67(2016) no.3, S.707-714
  19. Rotolo, D.; Rafols, I.; Hopkins, M.M.; Leydesdorff, L.: Strategic intelligence on emerging technologies : scientometric overlay mapping (2017) 0.00 
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    Journal of the Association for Information Science and Technology. 68(2017) no.1, S.214-233
  20. Comins, J.A.; Leydesdorff, L.: Identification of long-term concept-symbols among citations : do common intellectual histories structure citation behavior? (2017) 0.00 
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    Journal of the Association for Information Science and Technology. 68(2017) no.5, S.1224-1233

Authors