1,720,973 research outputs found
Phase synchronization of coupled Ginzburg-Landau equations
No full textThe occurrence of phase synchronization of a pair of unidirectionally coupled nonidentical Ginzburg-Landau equations is demonstrated and characterized using cyclic and extended phases. Furthermore, it is shown that weak coupling first leads to frequency synchronization and later to phase synchronization. For strong coupling there is evidence for generalized synchronization
Synchronization and control of coupled Ginzburg-Landau equations using local coupling
No full textIn this paper we discuss the properties of a recently introduced coupling scheme for spatially extended systems based on local spatially averaged coupling signals [see Z. Tasev et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. (to he published); and L. Junge er al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 9, 2265 (1999)]. Using the Ginzburg-Landau model, we performed an extensive numerical examination of this coupling scheme, i.e., a complete scan through the relevant coupling parameters. Furthermore, we demonstrate suppression and control of spatiotemporal chaos, e.g., stabilizing the homogeneous steady state and spatially localized control. As an application all model parameters of the Ginzburg-Landau equation rue estimated given only the local information of the system
Synchronization using dynamic coupling
No full textA systematic coupling procedure is introduced for synchronizing arbitrary chaotic dynamical systems. This coupling exploits the existing contraction properties of the flow and surpresses divergence only along those directions in state space, where the underlying flow is not contracting. In this way, systems can be synchronized using a minimum of transmitted information for guaranteed high-quality synchronization. Applications in combination with sporadic driving and in partitioned state spaces are numerically illustrated
Synchronization of Kuramoto-Sivashinsky equations using spatially local coupling
No full textThe synchronization properties of a pair of Kuramoto-Sivashinsky equations are examined using only a finite number of coupling signals that are given in terms of local spatial averages. The dependence of the synchronization on the number of coupling signals and the width of the spatial average intervals is examined, including spatiotemporal intermittency of the synchronization error near the onset of synchronization
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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