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Loet Leydesdorff

Publications and source records attributed to Loet Leydesdorff.

At least 181 records · Page 10Linked to original sources

Emerging Search Regimes: Measuring Co-evolutions among Research, Science, and Society

Scientometric data is used to investigate empirically the emergence of search regimes in Biotechnology, Genomics, and Nanotechnology. Complex regimes can emerge when three independent sources of variance interact. In our model, researchers can be considered as the nodes that carry the science system. Research is geographically situated with site-specific skills, tacit knowledge and infrastructures. Second, the emergent science level refers to the formal communication of codified knowledge published in journals. Third, the socio-economic dynamics indicate the ways in which knowledge production relates to society. Although Biotechnology, Genomics, and Nanotechnology can all be characterised by rapid growth and divergent dynamics, the regimes differ in terms of self-organization among these three sources of variance. The scope of opportunities for researchers to contribute within the constraints of the existing body of knowledge are different in each field. Furthermore, the relevance of the context of application contributes to the knowledge dynamics to various degrees.

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University-Industry-Government Relations in China: An emergent national system of innovations

Since 1992, a new Chinese innovation system has been emerging in terms of university-industry-government relations. In recent years, science parks, incubators, and high-tech development zones have been provided with strong incentives. The commitment of the Chinese government to the further introduction of a market economy has been elaborated with a focus on the knowledge-base. The model of institutional adjustments has been replaced with systemic and evolutionary thinking about niche development and human resource management. Government interventions remain important for interfacing knowledge-based developments with those on the market. For example, new legislation on issues of "intellectual property rights" is crucial to the absorption of venture capital into these developments.

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What the Cited and Citing Environments Reveal of "Advances in Atmospheric Sciences"?

The networking ability of journals reflects their academic influence among peer journals. This paper analyzes the cited and citing environments of the journal--Advances in Atmospheric Sciences--using methods from social network analysis. The journal has been actively participating in the international journal environment, but one has a tendency to cite papers published in international journals. Advances in Atmospheric Sciences is intensely interrelated with international peer journals in terms of similar citing pattern. However, there is still room for an increase in its academic visibility given the comparatively smaller reception in terms of cited references.

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Fractional counting of citations in research evaluation: An option for cross- and interdisciplinary assessments

In the case of the scientometric evaluation of multi- or interdisciplinary units one risks to compare apples with oranges: each paper has to assessed in comparison to an appropriate reference set. We suggest that the set of citing papers first can be considered as the relevant representation of the field of impact. In order to normalize for differences in citation behavior among fields, citations can be fractionally counted proportionately to the length of the reference lists in the citing papers. This new method enables us to compare among units with different disciplinary affiliations at the paper level and also to assess the statistical significance of differences among sets. Twenty-seven departments of the Tsinghua University in Beijing are thus compared. Among them, the Department of Chinese Language and Linguistics is upgraded from the 19th to the second position in the ranking. The overall impact of 19 of the 27 departments is not significantly different at the 5% level when thus normalized for different citation potentials.

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Remaining problems with the "New Crown Indicator" (MNCS) of the CWTS

In their article, entitled "Towards a new crown indicator: some theoretical considerations," Waltman et al. (2010; at arXiv:1003.2167) show that the "old crown indicator" of CWTS in Leiden was mathematically inconsistent and that one should move to the normalization as applied in the "new crown indicator." Although we now agree about the statistical normalization, the "new crown indicator" inherits the scientometric problems of the "old" one in treating subject categories of journals as a standard for normalizing differences in citation behavior among fields of science. We further note that the "mean" is not a proper statistics for measuring differences among skewed distributions. Without changing the acronym of "MNCS," one could define the "Median Normalized Citation Score." This would relate the new crown indicator directly to the percentile approach that is, for example, used in the Science and Engineering Indicators of US National Science Board (2010). The median is by definition equal to the 50th percentile. The indicator can thus easily be extended with the 1% (= 99th percentile) most highly-cited papers (Bornmann et al., in press). The seeming disadvantage of having to use non-parametric statistics is more than compensated by possible gains in the precision.

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How to evaluate universities in terms of their relative citation impacts: Fractional counting of citations and the normalization of differences among disciplines

Fractional counting of citations can improve on ranking of multi-disciplinary research units (such as universities) by normalizing the differences among fields of science in terms of differences in citation behavior. Furthermore, normalization in terms of citing papers abolishes the unsolved questions in scientometrics about the delineation of fields of science in terms of journals and normalization when comparing among different journals. Using publication and citation data of seven Korean research universities, we demonstrate the advantages and the differences in the rankings, explain the possible statistics, and suggest ways to visualize the differences in (citing) audiences in terms of a network.

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How fractional counting affects the Impact Factor: Normalization in terms of differences in citation potentials among fields of science

The ISI-Impact Factors suffer from a number of drawbacks, among them the statistics-why should one use the mean and not the median?-and the incomparability among fields of science because of systematic differences in citation behavior among fields. Can these drawbacks be counteracted by counting citation weights fractionally instead of using whole numbers in the numerators? (i) Fractional citation counts are normalized in terms of the citing sources and thus would take into account differences in citation behavior among fields of science. (ii) Differences in the resulting distributions can be tested statistically for their significance at different levels of aggregation. (iii) Fractional counting can be generalized to any document set including journals or groups of journals, and thus the significance of differences among both small and large sets can be tested. A list of fractionally counted Impact Factors for 2008 is available online at http://www.leydesdorff.net/weighted_if/weighted_if.xls. The in-between group variance among the thirteen fields of science identified in the U.S. Science and Engineering Indicators is not statistically significant after this normalization. Although citation behavior differs largely between disciplines, the reflection of these differences in fractionally counted citation distributions could not be used as a reliable instrument for the classification.

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Indicators of the Interdisciplinarity of Journals: Diversity, Centrality, and Citations

A citation-based indicator for interdisciplinarity has been missing hitherto among the set of available journal indicators. In this study, we investigate network indicators (betweenness centrality), journal indicators (Shannon entropy, the Gini coefficient), and more recently proposed Rao-Stirling measures for "interdisciplinarity." The latter index combines the statistics of both citation distributions of journals (vector-based) and distances in citation networks among journals (matrix-based). The effects of various normalizations are specified and measured using the matrix of 8,207 journals contained in the Journal Citation Reports of the (Social) Science Citation Index 2008. Betweenness centrality in symmetrical (1-mode) cosine-normalized networks provides an indicator outperforming betweenness in the asymmetrical (2-mode) citation network. Among the vector-based indicators, Shannon entropy performs better than the Gini coefficient, but is sensitive to size. Science and Nature, for example, are indicated at the top of the list. The new diversity measure provides reasonable results when (1 - cosine) is assumed as a measure for the distance, but results using Euclidean distances were difficult to interpret.

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The Development of the Journal Environment of Leonardo

We present animations based on the aggregated journal-journal citations of Leonardo during the period 1974-2008. Leonardo is mainly cited by journals outside the arts domain for cultural reasons, for example, in neuropsychology and physics. Articles in Leonardo itself cite a large number of journals, but with a focus on the arts. Animations at this level of aggregation enable us to show the history of the journal from a network perspective.

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The Triple Helix Perspective of Innovation Systems

Alongside the neo-institutional model of networked relations among universities, industries, and governments, the Triple Helix can be provided with a neo-evolutionary interpretation as three selection environments operating upon one another: markets, organizations, and technological opportunities. How are technological innovation systems different from national ones? The three selection environments fulfill social functions: wealth creation, organization control, and organized knowledge production. The main carriers of this system-industry, government, and academia-provide the variation both recursively and by interacting among them under the pressure of competition. Empirical case studies enable us to understand how these evolutionary mechanisms can be expected to operate in historical instance. The model is needed for distinguishing, for example, between trajectories and regimes.

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Communicative Competencies and the Structuration of Expectations: The creative tension between Habermas' critical theory and Luhmann's social systems theory

I elaborate on the tension between Luhmann's social systems theory and Habermas' theory of communicative action, and argue that this tension can be resolved by focusing on language as the interhuman medium of the communication which enables us to develop symbolically generalized media of communication such as truth, love, power, etc. Following Luhmann, the layers of self-organization among the differently codified subsystems of communication versus organization of meaning at contingent interfaces can analytically be distinguished as compatible, yet empirically researchable alternatives to Habermas' distinction between "system" and "lifeworld." Mediation by a facilitator can then be considered as a special case of organizing historically contingent translations among the evolutionarily developing fluxes of intentions and expectations. Accordingly, I suggest modifying Giddens' terminology into "a theory of the structuration of expectations."

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Scopus' SNIP Indicator

Rejoinder to Moed [arXiv:1005.4906]: Our main objection is against developing new indicators which, like some of the older ones (for example, the "crown indicator" of CWTS), do not allow for indicating error because they do not provide a statistics, but are based, in our opinion, on a violation of the order of operations. The claim of validity for the SNIP indicator is hollow because the normalizations are based on field classifications which are not valid. Both problems can perhaps be solved by using fractional counting.

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Normalization at the field level: fractional counting of citations

Van Raan et al. (2010; arXiv:1003.2113) have proposed a new indicator (MNCS) for field normalization. Since field normalization is also used in the Leiden Rankings of universities, we elaborate our critique of journal normalization in Opthof & Leydesdorff (2010; arXiv:1002.2769) in this rejoinder concerning field normalization. Fractional citation counting thoroughly solves the issue of normalization for differences in citation behavior among fields. This indicator can also be used to obtain a normalized impact factor.

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The Communication of Meaning and the Structuration of Expectations: Giddens' "structuration theory" and Luhmann's "self-organization"

The communication of meaning as different from (Shannon-type) information is central to Luhmann's social systems theory and Giddens' structuration theory of action. These theories share an emphasis on reflexivity, but focus on meaning along a divide between inter-human communication and intentful action as two different systems of reference. Recombining these two theories into a theory about the structuration of expectations, interactions, organization, and self-organization of intentional communications can be simulated based on algorithms from the computation of anticipatory systems. The self-organizing and organizing layers remain rooted in the double contingency of the human encounter which provides the variation. Organization and self-organization of communication are reflexive upon and therefore reconstructive of each other. Using mutual information in three dimensions, the imprint of meaning processing in the modeling system on the historical organization of uncertainty in the modeled system can be measured. This is shown empirically in the case of intellectual organization as "structurating" structure in the textual domain of scientific articles.

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Eugene Garfield and Algorithmic Historiography: Co-Words, Co-Authors, and Journal Names

Algorithmic historiography was proposed by Eugene Garfield in collaboration with Irving Sher in the 1960s, but further developed only recently into HistCite^{TM} with Alexander Pudovkin. As in history writing, HistCite^{TM} reconstructs by drawing intellectual lineages. In addition to cited references, however, documents can be attributed a multitude of other variables such as title words, keywords, journal names, author names, and even full texts. New developments in multidimensional scaling (MDS) enable us not only to visualize these patterns at each moment of time, but also to animate them over time. Using title words, co-authors, and journal names in Garfield's oeuvre, the method is demonstrated and further developed in this paper (and in the animation at http://www.leydesdorff.net/garfield/animation). The variety and substantive content of the animation enables us to write, visualize, and animate the author's intellectual history.

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Normalization, CWTS indicators, and the Leiden Rankings: Differences in citation behavior at the level of fields

Van Raan et al. (2010; arXiv:1003.2113) have proposed a new indicator (MNCS) for field normalization. Since field normalization is also used in the Leiden Rankings of universities, we elaborate our critique of journal normalization in Opthof & Leydesdorff (2010; arXiv:1002.2769) in this rejoinder concerning field normalization. Fractional citation counting thoroughly solves the issue of normalization for differences in citation behavior among fields. This indicator can also be used to obtain a normalized impact factor.

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The Production of Probabilistic Entropy in Structure/Action Contingency Relations

Luhmann (1984) defined society as a communication system which is structurally coupled to, but not an aggregate of, human action systems. The communication system is then considered as self-organizing ("autopoietic"), as are human actors. Communication systems can be studied by using Shannon's (1948) mathematical theory of communication. The update of a network by action at one of the local nodes is then a well-known problem in artificial intelligence (Pearl 1988). By combining these various theories, a general algorithm for probabilistic structure/action contingency can be derived. The consequences of this contingency for each system, its consequences for their further histories, and the stabilization on each side by counterbalancing mechanisms are discussed, in both mathematical and theoretical terms. An empirical example is elaborated.

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Scopus's Source Normalized Impact per Paper (SNIP) versus a Journal Impact Factor based on Fractional Counting of Citations

Impact factors (and similar measures such as the Scimago Journal Rankings) suffer from two problems: (i) citation behavior varies among fields of science and therefore leads to systematic differences, and (ii) there are no statistics to inform us whether differences are significant. The recently introduced SNIP indicator of Scopus tries to remedy the first of these two problems, but a number of normalization decisions are involved which makes it impossible to test for significance. Using fractional counting of citations-based on the assumption that impact is proportionate to the number of references in the citing documents-citations can be contextualized at the paper level and aggregated impacts of sets can be tested for their significance. It can be shown that the weighted impact of Annals of Mathematics (0.247) is not so much lower than that of Molecular Cell (0.386) despite a five-fold difference between their impact factors (2.793 and 13.156, respectively).

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