-
Leydesdorff, L.: ¬The construction and globalization of the knowledge base in inter-human communication systems (2003)
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- Date
- 22. 5.2003 19:48:04
- Source
- Canadian Journal of Communication 28(2003), H.3, S. -
-
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)
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- 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
-
Leydesdorff, L.: Can networks of journal-journal citations be used as indicators of change in the social sciences? (2003)
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- Date
- 6.11.2005 19:02:22
- Source
- Journal of documentation. 59(2003) no.1, S.84-104
-
Leydesdorff, L.; Sun, Y.: National and international dimensions of the Triple Helix in Japan : university-industry-government versus international coauthorship relations (2009)
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- 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
-
Leydesdorff, L.; Bornmann, L.; Wagner, C.S.: ¬The relative influences of government funding and international collaboration on citation impact (2019)
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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
-
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)
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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
-
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)
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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
-
Leydesdorff, L.; Johnson, M.W.; Ivanova, I.: Toward a calculus of redundancy : signification, codification, and anticipation in cultural evolution (2018)
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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
-
Leydesdorff, L.: How are new citation-based journal indicators adding to the bibliometric toolbox? (2009)
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- 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
-
Leydesdorff, L.: Should co-occurrence data be normalized : a rejoinder (2007)
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- Source
- Journal of the American Society for Information Science and Technology. 58(2007) no.14, S.2411-2413
-
Leydesdorff, L.: Accounting for the uncertainty in the evaluation of percentile ranks (2012)
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- Source
- Journal of the American Society for Information Science and Technology. 63(2012) no.11, S.2349-2350
-
Bornmann, L.; Leydesdorff, L.: Statistical tests and research assessments : a comment on Schneider (2012) (2013)
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- Source
- Journal of the American Society for Information Science and Technology. 64(2013) no.6, S.1306-1308
-
Leydesdorff, L.; Wagner, C,; Bornmann, L.: Replicability and the public/private divide (2016)
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- Source
- Journal of the Association for Information Science and Technology. 67(2016) no.7, S.1777-1778
-
Leydesdorff, L.: ¬A sociological theory of communication : the self-organization of the knowledge-based society (2001)
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- Footnote
- Rez. in: JASIST 53(2002) no.1, S.61-62 (E.G. Ackermann): "This brief summary cannot do justice to the intellectual depth, philosophical richness of the theoretical models, and their implications presented by Leydesdorff in his book. Next to this, the caveats presented earlier in this review are relatively minor. For all that, this book is not an "easy" read, nor is it for the theoretically or philosophically faint of heart. The content is certainly accessible to those with the interest and the stamina to see it through to the end, and would repay those who reread it with further insight and understanding. This book is recommended especially for the reader who is looking for a well-developed, general sociological theory of communication with a strong philosophical basis upon which to build a postmodern, deconstructionist research methodology"
- Pages
- 351 S
-
Leydesdorff, L.; Bensman, S.: Classification and Powerlaws : the logarithmic transformation (2006)
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- Source
- Journal of the American Society for Information Science and Technology. 57(2006) no.11, S.1470-1486
-
Leydesdorff, L.; Strand, Oe.: ¬The Swedish system of innovation : regional synergies in a knowledge-based economy (2013)
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- Location
- S
- Source
- Journal of the American Society for Information Science and Technology. 64(2013) no.9, S.1890-1902
-
Leydesdorff, L.; Heimeriks, G.; Rotolo, D.: Journal portfolio analysis for countries, cities, and organizations : maps and comparisons (2016)
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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
-
Zhou, Q.; Leydesdorff, L.: ¬The normalization of occurrence and co-occurrence matrices in bibliometrics using Cosine similarities and Ochiai coefficients (2016)
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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
-
Leydesdorff, L.; Heimeriks, G.: ¬The self-organization of the European information society : the case of "biotechnology" (2001)
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- Footnote
- Vgl. auch die Stellungnahme von P. van den Besselaar: Empirical evidence of self-organization? in: JASIST 54(2003) no.1, S.87-90.
- Source
- Journal of the American Society for Information Science and technology. 52(2001) no.14, S.1262-1274
-
Leydesdorff, L.: ¬The generation of aggregated journal-journal citation maps on the basis of the CD-ROM version of the Science Citation Index (1994)
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- Source
- Scientometrics. 31(1994) no.1, S.59-84
