Search (9 results, page 1 of 1)

Leydesdorff, L.: Patent classifications as indicators of intellectual organization (2008) 0.02
```
0.015178238 = product of:
  0.030356476 = sum of:
    0.030356476 = product of:
      0.060712952 = sum of:
        0.060712952 = weight(_text_:classification in 2002) [ClassicSimilarity], result of:
          0.060712952 = score(doc=2002,freq=6.0), product of:
            0.16603322 = queryWeight, product of:
              3.1847067 = idf(docFreq=4974, maxDocs=44218)
              0.05213454 = queryNorm
            0.3656675 = fieldWeight in 2002, product of:
              2.4494898 = tf(freq=6.0), with freq of:
                6.0 = termFreq=6.0
              3.1847067 = idf(docFreq=4974, maxDocs=44218)
              0.046875 = fieldNorm(doc=2002)
      0.5 = coord(1/2)
  0.5 = coord(1/2)
```
Abstract

Using the 138,751 patents filed in 2006 under the Patent Cooperation Treaty, co-classification analysis is pursued on the basis of three- and four-digit codes in the International Patent Classification (IPC, 8th ed.). The co-classifications among the patents enable us to analyze and visualize the relations among technologies at different levels of aggregation. The hypothesis that classifications might be considered as the organizers of patents into classes, and therefore that co-classification patterns - more than co-citation patterns - might be useful for mapping, is not corroborated. The classifications hang weakly together, even at the four-digit level; at the country level, more specificity can be made visible. However, countries are not the appropriate units of analysis because patent portfolios are largely similar in many advanced countries in terms of the classes attributed. Instead of classes, one may wish to explore the mapping of title words as a better approach to visualize the intellectual organization of patents.
Leydesdorff, L.: Clusters and maps of science journals based on bi-connected graphs in Journal Citation Reports (2004) 0.01
```
0.012392979 = product of:
  0.024785958 = sum of:
    0.024785958 = product of:
      0.049571916 = sum of:
        0.049571916 = weight(_text_:classification in 4427) [ClassicSimilarity], result of:
          0.049571916 = score(doc=4427,freq=4.0), product of:
            0.16603322 = queryWeight, product of:
              3.1847067 = idf(docFreq=4974, maxDocs=44218)
              0.05213454 = queryNorm
            0.29856625 = fieldWeight in 4427, product of:
              2.0 = tf(freq=4.0), with freq of:
                4.0 = termFreq=4.0
              3.1847067 = idf(docFreq=4974, maxDocs=44218)
              0.046875 = fieldNorm(doc=4427)
      0.5 = coord(1/2)
  0.5 = coord(1/2)
```
Abstract

The aggregated journal-journal citation matrix derived from Journal Citation Reports 2001 can be decomposed into a unique subject classification using the graph-analytical algorithm of bi-connected components. This technique was recently incorporated in software tools for social network analysis. The matrix can be assessed in terms of its decomposability using articulation points which indicate overlap between the components. The articulation points of this set did not exhibit a next-order network of "general science" journals. However, the clusters differ in size and in terms of the internal density of their relations. A full classification of the journals is provided in the Appendix. The clusters can also be extracted and mapped for the visualization.
Bensman, S.J.; Leydesdorff, L.: Definition and identification of journals as bibliographic and subject entities : librarianship versus ISI Journal Citation Reports methods and their effect on citation measures (2009) 0.01
```
0.012392979 = product of:
  0.024785958 = sum of:
    0.024785958 = product of:
      0.049571916 = sum of:
        0.049571916 = weight(_text_:classification in 2840) [ClassicSimilarity], result of:
          0.049571916 = score(doc=2840,freq=4.0), product of:
            0.16603322 = queryWeight, product of:
              3.1847067 = idf(docFreq=4974, maxDocs=44218)
              0.05213454 = queryNorm
            0.29856625 = fieldWeight in 2840, product of:
              2.0 = tf(freq=4.0), with freq of:
                4.0 = termFreq=4.0
              3.1847067 = idf(docFreq=4974, maxDocs=44218)
              0.046875 = fieldNorm(doc=2840)
      0.5 = coord(1/2)
  0.5 = coord(1/2)
```
Abstract

This paper explores the ISI Journal Citation Reports (JCR) bibliographic and subject structures through Library of Congress (LC) and American research libraries cataloging and classification methodology. The 2006 Science Citation Index JCR Behavioral Sciences subject category journals are used as an example. From the library perspective, the main fault of the JCR bibliographic structure is that the JCR mistakenly identifies journal title segments as journal bibliographic entities, seriously affecting journal rankings by total cites and the impact factor. In respect to JCR subject structure, the title segment, which constitutes the JCR bibliographic basis, is posited as the best bibliographic entity for the citation measurement of journal subject relationships. Through factor analysis and other methods, the JCR subject categorization of journals is tested against their LC subject headings and classification. The finding is that JCR and library journal subject analyses corroborate, clarify, and correct each other.

Leydesdorff, L.: ¬The construction and globalization of the knowledge base in inter-human communication systems (2003) 0.01

0.010595265 = product of:
  0.02119053 = sum of:
    0.02119053 = product of:
      0.04238106 = sum of:
        0.04238106 = weight(_text_:22 in 1621) [ClassicSimilarity], result of:
          0.04238106 = score(doc=1621,freq=2.0), product of:
            0.18256627 = queryWeight, product of:
              3.5018296 = idf(docFreq=3622, maxDocs=44218)
              0.05213454 = 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)
  0.5 = coord(1/2)

Date: 22. 5.2003 19:48:04

Leydesdorff, L.: Can networks of journal-journal citations be used as indicators of change in the social sciences? (2003) 0.01

0.010595265 = product of:
  0.02119053 = sum of:
    0.02119053 = product of:
      0.04238106 = sum of:
        0.04238106 = weight(_text_:22 in 4460) [ClassicSimilarity], result of:
          0.04238106 = score(doc=4460,freq=2.0), product of:
            0.18256627 = queryWeight, product of:
              3.5018296 = idf(docFreq=3622, maxDocs=44218)
              0.05213454 = 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)
  0.5 = coord(1/2)

Date: 6.11.2005 19:02:22

Leydesdorff, L.; Sun, Y.: National and international dimensions of the Triple Helix in Japan : university-industry-government versus international coauthorship relations (2009) 0.01

0.010595265 = product of:
  0.02119053 = sum of:
    0.02119053 = product of:
      0.04238106 = sum of:
        0.04238106 = weight(_text_:22 in 2761) [ClassicSimilarity], result of:
          0.04238106 = score(doc=2761,freq=2.0), product of:
            0.18256627 = queryWeight, product of:
              3.5018296 = idf(docFreq=3622, maxDocs=44218)
              0.05213454 = 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)
  0.5 = coord(1/2)

Date: 22. 3.2009 19:07:20

Rafols, I.; Leydesdorff, L.: Content-based and algorithmic classifications of journals : perspectives on the dynamics of scientific communication and indexer effects (2009) 0.01
```
0.010327483 = product of:
  0.020654965 = sum of:
    0.020654965 = product of:
      0.04130993 = sum of:
        0.04130993 = weight(_text_:classification in 3095) [ClassicSimilarity], result of:
          0.04130993 = score(doc=3095,freq=4.0), product of:
            0.16603322 = queryWeight, product of:
              3.1847067 = idf(docFreq=4974, maxDocs=44218)
              0.05213454 = queryNorm
            0.24880521 = fieldWeight in 3095, product of:
              2.0 = tf(freq=4.0), with freq of:
                4.0 = termFreq=4.0
              3.1847067 = idf(docFreq=4974, maxDocs=44218)
              0.0390625 = fieldNorm(doc=3095)
      0.5 = coord(1/2)
  0.5 = coord(1/2)
```
Abstract

The aggregated journal-journal citation matrix - based on the Journal Citation Reports (JCR) of the Science Citation Index - can be decomposed by indexers or algorithmically. In this study, we test the results of two recently available algorithms for the decomposition of large matrices against two content-based classifications of journals: the ISI Subject Categories and the field/subfield classification of Glänzel and Schubert (2003). The content-based schemes allow for the attribution of more than a single category to a journal, whereas the algorithms maximize the ratio of within-category citations over between-category citations in the aggregated category-category citation matrix. By adding categories, indexers generate between-category citations, which may enrich the database, for example, in the case of inter-disciplinary developments. Algorithmic decompositions, on the other hand, are more heavily skewed towards a relatively small number of categories, while this is deliberately counter-acted upon in the case of content-based classifications. Because of the indexer effects, science policy studies and the sociology of science should be careful when using content-based classifications, which are made for bibliographic disclosure, and not for the purpose of analyzing latent structures in scientific communications. Despite the large differences among them, the four classification schemes enable us to generate surprisingly similar maps of science at the global level. Erroneous classifications are cancelled as noise at the aggregate level, but may disturb the evaluation locally.
Leydesdorff, L.: Can scientific journals be classified in terms of aggregated journal-journal citation relations using the Journal Citation Reports? (2006) 0.01
```
0.00876316 = product of:
  0.01752632 = sum of:
    0.01752632 = product of:
      0.03505264 = sum of:
        0.03505264 = weight(_text_:classification in 5046) [ClassicSimilarity], result of:
          0.03505264 = score(doc=5046,freq=2.0), product of:
            0.16603322 = queryWeight, product of:
              3.1847067 = idf(docFreq=4974, maxDocs=44218)
              0.05213454 = queryNorm
            0.21111822 = fieldWeight in 5046, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              3.1847067 = idf(docFreq=4974, maxDocs=44218)
              0.046875 = fieldNorm(doc=5046)
      0.5 = coord(1/2)
  0.5 = coord(1/2)
```
Abstract

The aggregated citation relations among journals included in the Science Citation Index provide us with a huge matrix, which can be analyzed in various ways. By using principal component analysis or factor analysis, the factor scores can be employed as indicators of the position of the cited journals in the citing dimensions of the database. Unrotated factor scores are exact, and the extraction of principal components can be made stepwise because the principal components are independent. Rotation may be needed for the designation, but in the rotated solution a model is assumed. This assumption can be legitimated on pragmatic or theoretical grounds. Because the resulting outcomes remain sensitive to the assumptions in the model, an unambiguous classification is no longer possible in this case. However, the factor-analytic solutions allow us to test classifications against the structures contained in the database; in this article the process will be demonstrated for the delineation of a set of biochemistry journals.

Leydesdorff, L.; Bensman, S.: Classification and Powerlaws : the logarithmic transformation (2006) 0.01

0.00876316 = product of:
  0.01752632 = sum of:
    0.01752632 = product of:
      0.03505264 = sum of:
        0.03505264 = weight(_text_:classification in 6007) [ClassicSimilarity], result of:
          0.03505264 = score(doc=6007,freq=2.0), product of:
            0.16603322 = queryWeight, product of:
              3.1847067 = idf(docFreq=4974, maxDocs=44218)
              0.05213454 = queryNorm
            0.21111822 = fieldWeight in 6007, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              3.1847067 = idf(docFreq=4974, maxDocs=44218)
              0.046875 = fieldNorm(doc=6007)
      0.5 = coord(1/2)
  0.5 = coord(1/2)

Search (9 results, page 1 of 1)

Authors

Themes