preprint versions available

Loet Leydesdorff loet at LEYDESDORFF.NET
Tue Jun 26 02:52:21 EDT 2001

"Indicators of Structural Change in the Dynamics of Science:
 Entropy Statistics of the SCI Journal Citation Reports" (in preparation)

Can change in citation patterns among journals be used as an indicator of
structural change in the organization of the sciences? Aggregated
journal-journal citations for 1999 are compared with similar data in the
Journal Citation Report 1998 of the Science Citation Index. In addition to
indicating local change, probabilistic entropy measures enable us to
analyze changes in distributions at different levels of aggregation. The
results of various possible indicators are discussed and compared, for
example, by elaborating the journal-journal mappings. The relevance of this
indicator for science and technology policies is further specified.

"The Appreciation of Models of Complex Dynamics in the Case of
Technological Innovation," Paper for the International Conference on
Computing Antipatory Systems CASYS'2001, Liège, Belgium, August 2001.

Arthur’s (1988 and 1989) model of the ‘lock-in’ predicates the dominance of
a single technology, while Kauffman’s (1993 and 1995) NK-model investigates
the emergence of different sub-optima in a ‘rugged fitness landscape.’ Can
the two mechanisms also be offset against each other? Under what conditions
can one expect a technological monopoly or an oligopoly to prevail? What
can serve as a discursive ground for making comparisons among the results
of these sophisticated models? In this study, the two models are first
reconstructed using a common language for the coding. Second, I address the
question of how one can let the one model disturb the other. The reduction
of the complexity in the coding enables us to focus on the theoretical
assumptions. For example, the introduction of a Schumpeterian dynamics of
‘creative destruction’ can be shown to introduce variation in a rugged
fitness landscape. The results of the simulations will be made visual using
the technique of a cellular automaton.

Loet Leydesdorff
Science & Technology Dynamics, University of Amsterdam

Amsterdam School of Communications Research (ASCoR),
Oude Hoogstraat 24, 1012 CE  Amsterdam, The Netherlands

Tel.: +31-20- 525 6598; fax: +31-20- 525 3681

mailto:loet at ;

"A Sociological Theory of Communication: The Self-Organization
of the Knowledge-Based Society"

"The Challenge of Scientometrics: The development, measurement,
and self-organization of scientific communications"

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