-
Leydesdorff, L.: Can networks of journal-journal citations be used as indicators of change in the social sciences? (2003)
0.02
0.0205279 = product of:
0.0410558 = sum of:
0.0410558 = sum of:
0.003609657 = weight(_text_:s in 4460) [ClassicSimilarity], result of:
0.003609657 = score(doc=4460,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = 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)
0.03744614 = weight(_text_:22 in 4460) [ClassicSimilarity], result of:
0.03744614 = score(doc=4460,freq=2.0), product of:
0.16130796 = queryWeight, product of:
3.5018296 = idf(docFreq=3622, maxDocs=44218)
0.046063907 = 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)
- 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)
0.02
0.0205279 = product of:
0.0410558 = sum of:
0.0410558 = sum of:
0.003609657 = weight(_text_:s in 2761) [ClassicSimilarity], result of:
0.003609657 = score(doc=2761,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = 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)
0.03744614 = weight(_text_:22 in 2761) [ClassicSimilarity], result of:
0.03744614 = score(doc=2761,freq=2.0), product of:
0.16130796 = queryWeight, product of:
3.5018296 = idf(docFreq=3622, maxDocs=44218)
0.046063907 = 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)
- 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)
0.02
0.0205279 = product of:
0.0410558 = sum of:
0.0410558 = sum of:
0.003609657 = weight(_text_:s in 4681) [ClassicSimilarity], result of:
0.003609657 = score(doc=4681,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = 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)
0.03744614 = weight(_text_:22 in 4681) [ClassicSimilarity], result of:
0.03744614 = score(doc=4681,freq=2.0), product of:
0.16130796 = queryWeight, product of:
3.5018296 = idf(docFreq=3622, maxDocs=44218)
0.046063907 = 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)
- 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)
0.02
0.017106583 = product of:
0.034213167 = sum of:
0.034213167 = sum of:
0.0030080476 = weight(_text_:s in 4186) [ClassicSimilarity], result of:
0.0030080476 = score(doc=4186,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = 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)
0.03120512 = weight(_text_:22 in 4186) [ClassicSimilarity], result of:
0.03120512 = score(doc=4186,freq=2.0), product of:
0.16130796 = queryWeight, product of:
3.5018296 = idf(docFreq=3622, maxDocs=44218)
0.046063907 = 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)
- 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
-
Leydesdorff, L.: Accounting for the uncertainty in the evaluation of percentile ranks (2012)
0.00
0.0018048285 = product of:
0.003609657 = sum of:
0.003609657 = product of:
0.007219314 = sum of:
0.007219314 = weight(_text_:s in 447) [ClassicSimilarity], result of:
0.007219314 = score(doc=447,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = 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)
0.5 = coord(1/2)
0.5 = coord(1/2)
- Source
- Journal of the American Society for Information Science and Technology. 63(2012) no.11, S.2349-2350
-
Leydesdorff, L.; Bensman, S.: Classification and Powerlaws : the logarithmic transformation (2006)
0.00
0.0012762066 = product of:
0.0025524131 = sum of:
0.0025524131 = product of:
0.0051048263 = sum of:
0.0051048263 = weight(_text_:s in 6007) [ClassicSimilarity], result of:
0.0051048263 = score(doc=6007,freq=4.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = queryNorm
0.101928525 = fieldWeight in 6007, product of:
2.0 = tf(freq=4.0), with freq of:
4.0 = termFreq=4.0
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046875 = fieldNorm(doc=6007)
0.5 = coord(1/2)
0.5 = coord(1/2)
- Source
- Journal of the American Society for Information Science and Technology. 57(2006) no.11, S.1470-1486
-
Leydesdorff, L.; Heimeriks, G.; Rotolo, D.: Journal portfolio analysis for countries, cities, and organizations : maps and comparisons (2016)
0.00
0.0012762066 = product of:
0.0025524131 = sum of:
0.0025524131 = product of:
0.0051048263 = sum of:
0.0051048263 = weight(_text_:s in 2781) [ClassicSimilarity], result of:
0.0051048263 = score(doc=2781,freq=4.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = queryNorm
0.101928525 = fieldWeight in 2781, product of:
2.0 = tf(freq=4.0), with freq of:
4.0 = termFreq=4.0
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046875 = fieldNorm(doc=2781)
0.5 = coord(1/2)
0.5 = coord(1/2)
- 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)
0.00
0.0012762066 = product of:
0.0025524131 = sum of:
0.0025524131 = product of:
0.0051048263 = sum of:
0.0051048263 = weight(_text_:s in 3161) [ClassicSimilarity], result of:
0.0051048263 = score(doc=3161,freq=4.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = queryNorm
0.101928525 = fieldWeight in 3161, product of:
2.0 = tf(freq=4.0), with freq of:
4.0 = termFreq=4.0
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046875 = fieldNorm(doc=3161)
0.5 = coord(1/2)
0.5 = coord(1/2)
- 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)
0.00
0.0010635054 = product of:
0.0021270108 = sum of:
0.0021270108 = product of:
0.0042540217 = sum of:
0.0042540217 = weight(_text_:s in 6524) [ClassicSimilarity], result of:
0.0042540217 = score(doc=6524,freq=4.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = queryNorm
0.08494043 = fieldWeight in 6524, product of:
2.0 = tf(freq=4.0), with freq of:
4.0 = termFreq=4.0
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.0390625 = fieldNorm(doc=6524)
0.5 = coord(1/2)
0.5 = coord(1/2)
- 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)
0.00
0.0010528166 = product of:
0.0021056333 = sum of:
0.0021056333 = product of:
0.0042112665 = sum of:
0.0042112665 = weight(_text_:s in 8281) [ClassicSimilarity], result of:
0.0042112665 = score(doc=8281,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = queryNorm
0.08408674 = fieldWeight in 8281, 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=8281)
0.5 = coord(1/2)
0.5 = coord(1/2)
- Source
- Scientometrics. 31(1994) no.1, S.59-84
-
Leydesdorff, L.: Theories of citation? (1999)
0.00
0.0010528166 = product of:
0.0021056333 = sum of:
0.0021056333 = product of:
0.0042112665 = sum of:
0.0042112665 = weight(_text_:s in 5130) [ClassicSimilarity], result of:
0.0042112665 = score(doc=5130,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = queryNorm
0.08408674 = fieldWeight in 5130, 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=5130)
0.5 = coord(1/2)
0.5 = coord(1/2)
- Source
- Scientometrics. 43(1998) no.1, S.5-25
-
Leydesdorff, L.: Dynamic and evolutionary updates of classificatory schemes in scientific journal structures (2002)
0.00
0.0010528166 = product of:
0.0021056333 = sum of:
0.0021056333 = product of:
0.0042112665 = sum of:
0.0042112665 = weight(_text_:s in 1249) [ClassicSimilarity], result of:
0.0042112665 = score(doc=1249,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = queryNorm
0.08408674 = fieldWeight in 1249, 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=1249)
0.5 = coord(1/2)
0.5 = coord(1/2)
- Source
- Journal of the American Society for Information Science and technology. 53(2002) no.12, S.987-994
-
Leydesdorff, L.: Similarity measures, author cocitation Analysis, and information theory (2005)
0.00
0.0010528166 = product of:
0.0021056333 = sum of:
0.0021056333 = product of:
0.0042112665 = sum of:
0.0042112665 = weight(_text_:s in 3471) [ClassicSimilarity], result of:
0.0042112665 = score(doc=3471,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = 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)
0.5 = coord(1/2)
0.5 = coord(1/2)
- Source
- Journal of the American Society for Information Science and Technology. 56(2005) no.7, S.769-772
-
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
0.0010528166 = product of:
0.0021056333 = sum of:
0.0021056333 = product of:
0.0042112665 = sum of:
0.0042112665 = weight(_text_:s in 4466) [ClassicSimilarity], result of:
0.0042112665 = score(doc=4466,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = queryNorm
0.08408674 = fieldWeight in 4466, 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=4466)
0.5 = coord(1/2)
0.5 = coord(1/2)
- Source
- Journal of the American Society for Information Science and Technology. 62(2011) no.6, S.1146-1155
-
Marx, W.; Bornmann, L.; Barth, A.; Leydesdorff, L.: Detecting the historical roots of research fields by reference publication year spectroscopy (RPYS) (2014)
0.00
0.0010528166 = product of:
0.0021056333 = sum of:
0.0021056333 = product of:
0.0042112665 = sum of:
0.0042112665 = weight(_text_:s in 1238) [ClassicSimilarity], result of:
0.0042112665 = score(doc=1238,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = queryNorm
0.08408674 = fieldWeight in 1238, 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=1238)
0.5 = coord(1/2)
0.5 = coord(1/2)
- Source
- Journal of the Association for Information Science and Technology. 65(2014) no.4, S.751-764
-
Leydesdorff, L.: Why words and co-word cannot map the development of the science (1997)
0.00
9.0241426E-4 = product of:
0.0018048285 = sum of:
0.0018048285 = product of:
0.003609657 = sum of:
0.003609657 = weight(_text_:s in 147) [ClassicSimilarity], result of:
0.003609657 = score(doc=147,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = queryNorm
0.072074346 = fieldWeight in 147, 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=147)
0.5 = coord(1/2)
0.5 = coord(1/2)
- Source
- Journal of the American Society for Information Science. 48(1997) no.5, S.418-427
-
Leydesdorff, L.: Clusters and maps of science journals based on bi-connected graphs in Journal Citation Reports (2004)
0.00
9.0241426E-4 = product of:
0.0018048285 = sum of:
0.0018048285 = product of:
0.003609657 = sum of:
0.003609657 = weight(_text_:s in 4427) [ClassicSimilarity], result of:
0.003609657 = score(doc=4427,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = queryNorm
0.072074346 = fieldWeight in 4427, 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=4427)
0.5 = coord(1/2)
0.5 = coord(1/2)
- Source
- Journal of documentation. 60(2004) no.4, S.371-427
-
Leydesdorff, L.; Bihui, J.: Mapping the Chinese Science Citation Database in terms of aggregated journal-journal citation relations (2005)
0.00
9.0241426E-4 = product of:
0.0018048285 = sum of:
0.0018048285 = product of:
0.003609657 = sum of:
0.003609657 = weight(_text_:s in 4813) [ClassicSimilarity], result of:
0.003609657 = score(doc=4813,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = queryNorm
0.072074346 = fieldWeight in 4813, 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=4813)
0.5 = coord(1/2)
0.5 = coord(1/2)
- Source
- Journal of the American Society for Information Science and Technology. 56(2005) no.14, S.1469-1479
-
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)
0.00
9.0241426E-4 = product of:
0.0018048285 = sum of:
0.0018048285 = product of:
0.003609657 = sum of:
0.003609657 = weight(_text_:s in 70) [ClassicSimilarity], result of:
0.003609657 = score(doc=70,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = queryNorm
0.072074346 = 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)
0.046875 = fieldNorm(doc=70)
0.5 = coord(1/2)
0.5 = coord(1/2)
- Source
- Journal of the American Society for Information Science and Technology. 58(2007) no.2, S.223-236
-
Leydesdorff, L.: Betweenness centrality as an indicator of the interdisciplinarity of scientific journals (2007)
0.00
9.0241426E-4 = product of:
0.0018048285 = sum of:
0.0018048285 = product of:
0.003609657 = sum of:
0.003609657 = weight(_text_:s in 453) [ClassicSimilarity], result of:
0.003609657 = score(doc=453,freq=2.0), product of:
0.05008241 = queryWeight, product of:
1.0872376 = idf(docFreq=40523, maxDocs=44218)
0.046063907 = queryNorm
0.072074346 = fieldWeight in 453, 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=453)
0.5 = coord(1/2)
0.5 = coord(1/2)
- Source
- Journal of the American Society for Information Science and Technology. 58(2007) no.9, S.1303-1319
