1,720,957 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Scales
No full textWe introduce the notions of scale for sets and measures on metric space by generalizing the usual notions of dimension. Several versions of scales are introduced such as Hausdorff, packing, box, local and quantization. They are defined for different growth, allowing a refined study of infinite dimensional spaces. We prove general theorems comparing the different versions of scales. They are applied to describe geometries of ergodic decompositions, of the Wiener measure and from functional spaces. The first application solves a problem of Berger on the notions of emergence (2020); the second lies in the geometry of the Wiener measure and extends the work of Dereich–Lifshits (2005); the last refines Kolmogorov–Tikhomirov (1958) study on finitely differentiable functions
Complexity and bifurcation of the identity
No full textCette thèse est articulée autour de trois chapitres. Le premier expose le travail issu de l'article 'Scales'. Ce chapitre s'inscrit dans la théorie de la dimension avec des applications en probabilité, en systèmes dynamiques et en analyse fonctionnelle. Les échelles sont des familles d'invariants de plusieurs natures: Hausdorff, paquet, recouvrement, quantisation, ... et de différents taux de croissances, contenant ainsi la dimension ou l'ordre et permettant en particulier l'étude d'espaces de dimension infinie. Dans ce chapitre, les théorèmes établis de comparaison entre les différentes versions de dimensions sont étendus au cadre plus général des échelles. Ces résultats de comparaisons sont ensuite appliqués pour décrire la géométrie des espaces fonctionnels, de la mesure de Wiener et de la décomposition ergodique d'un système dynamique conservatif. Le second chapitre présente une collaboration avec P. Berger et N. Gourmelon qui a mené à l'article intitulé "Every Diffeomorphism is a total renormalization of an arbitrariraly close to identity map". Nous améliorons un résultat fondateur de D. Turaev. Précisément, nous montrons que tout difféomorphisme lisse à support compact dans la composante connexe de l'identité, sur une variété de la forme M X T où T est le cercle et M une variété de dimension au moins 1, peut être obtenu comme renormalisation totale d'une application proche de l'identité. Autrement dit, il existe une application g arbitrairement proche de l'identité telle que l'application de premier retour de g dans un certain domaine soit conjuguée à f, et de plus, l'orbite du domaine recouvre toute la variété. Notre preuve utilise de nouveaux outils qui utilisent bénéficient de propriétés de théorie des groupes et des algèbres de Lie. Enfin, le dernier chapitre s'inscrit dans la théorie de la bifurcation. Dans cette partie, une preuve alternative et géométrique d'un résultat de Gochenko-Meiss-Ovsyannikov est proposée. Leur résultat décrit l'apparition de points périodiques totalement paraboliques par perturbation lisse de difféomorphismes présentant des tangences homoclines. Cette nouvelle preuve permet d'obtenir une version paramétrique de ce résultat.This thesis is organized into three chapters. The first chapter presents the work from the article "Scales". This chapter is embedded in dimension theory with applications in probability, dynamical systems, and functional analysis. Scales are families of invariants of various types: Hausdorff, packing, covering, quantization, etc., and with different growth rates encompassing dimension or order, thus allowing the study of infinite-dimensional spaces. In this chapter, well-established comparison theorems between different versions of dimensions are extended to the more general framework of scales. These comparison results are then applied to describe the geometry of functional spaces, the Wiener measure, and the ergodic decomposition of a measurable dynamical system. The second chapter presents the article titled "Every Diffeomorphism is a Total Renormalization of an Arbitrarily Close to Identity Map" which is a joint work with P. Berger and N. Gourmelon. We improve a seminal result of D. Turaev using a new proof based on tools from group theory and Lie algebras. More precisely, we show that every smooth diffeomorphism, in the connected component of the identity and isotopic to identity by a compactly supported path, of a manifold of the form MxT where T is the circle and dim M is at least 1, can be obtained as a total renormalization of a close to identity map. In other words, there exists a map g arbitrarily close to the identity such that the first return map of g in a certain domain is conjugate to f, and moreover, the orbit of the domain covers the entire manifold. Finally, the last chapter contains a study of the perturbation of smooth diffeomorphisms presenting homoclinic tangencies. An alternative and geometric proof of a result of Gonchenko-Meiss-Ovsyannikov is brought. This states in particular that there exists totally parabolic periodic points, i.e. with eigenvalues on the unit circle, by arbitrarily small perturbation of a 3-dimensional diffeomorphism with a saddle with determinant equal to 1 and displaying a homoclinic tangency. In this last chapter, the geometric construction is brought to a new parametric counterpart of this result
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Complexité et bifurcation de l’identité
No full textThis thesis is organized into three chapters. The first chapter presents the work from the article "Scales". This chapter is embedded in dimension theory with applications in probability, dynamical systems, and functional analysis. Scales are families of invariants of various types: Hausdorff, packing, covering, quantization, etc., and with different growth rates encompassing dimension or order, thus allowing the study of infinite-dimensional spaces. In this chapter, well-established comparison theorems between different versions of dimensions are extended to the more general framework of scales. These comparison results are then applied to describe the geometry of functional spaces, the Wiener measure, and the ergodic decomposition of a measurable dynamical system. The second chapter presents the article titled "Every Diffeomorphism is a Total Renormalization of an Arbitrarily Close to Identity Map" which is a joint work with P. Berger and N. Gourmelon. We improve a seminal result of D. Turaev using a new proof based on tools from group theory and Lie algebras. More precisely, we show that every smooth diffeomorphism, in the connected component of the identity and isotopic to identity by a compactly supported path, of a manifold of the form MxT where T is the circle and dim M is at least 1, can be obtained as a total renormalization of a close to identity map. In other words, there exists a map g arbitrarily close to the identity such that the first return map of g in a certain domain is conjugate to f, and moreover, the orbit of the domain covers the entire manifold. Finally, the last chapter contains a study of the perturbation of smooth diffeomorphisms presenting homoclinic tangencies. An alternative and geometric proof of a result of Gonchenko-Meiss-Ovsyannikov is brought. This states in particular that there exists totally parabolic periodic points, i.e. with eigenvalues on the unit circle, by arbitrarily small perturbation of a 3-dimensional diffeomorphism with a saddle with determinant equal to 1 and displaying a homoclinic tangency. In this last chapter, the geometric construction is brought to a new parametric counterpart of this result.Cette thèse est articulée autour de trois chapitres. Le premier expose le travail issu de l'article 'Scales'. Ce chapitre s'inscrit dans la théorie de la dimension avec des applications en probabilité, en systèmes dynamiques et en analyse fonctionnelle. Les échelles sont des familles d'invariants de plusieurs natures: Hausdorff, paquet, recouvrement, quantisation, ... et de différents taux de croissances, contenant ainsi la dimension ou l'ordre et permettant en particulier l'étude d'espaces de dimension infinie. Dans ce chapitre, les théorèmes établis de comparaison entre les différentes versions de dimensions sont étendus au cadre plus général des échelles. Ces résultats de comparaisons sont ensuite appliqués pour décrire la géométrie des espaces fonctionnels, de la mesure de Wiener et de la décomposition ergodique d'un système dynamique conservatif. Le second chapitre présente une collaboration avec P. Berger et N. Gourmelon qui a mené à l'article intitulé "Every Diffeomorphism is a total renormalization of an arbitrariraly close to identity map". Nous améliorons un résultat fondateur de D. Turaev. Précisément, nous montrons que tout difféomorphisme lisse à support compact dans la composante connexe de l'identité, sur une variété de la forme M X T où T est le cercle et M une variété de dimension au moins 1, peut être obtenu comme renormalisation totale d'une application proche de l'identité. Autrement dit, il existe une application g arbitrairement proche de l'identité telle que l'application de premier retour de g dans un certain domaine soit conjuguée à f, et de plus, l'orbite du domaine recouvre toute la variété. Notre preuve utilise de nouveaux outils qui utilisent bénéficient de propriétés de théorie des groupes et des algèbres de Lie. Enfin, le dernier chapitre s'inscrit dans la théorie de la bifurcation. Dans cette partie, une preuve alternative et géométrique d'un résultat de Gochenko-Meiss-Ovsyannikov est proposée. Leur résultat décrit l'apparition de points périodiques totalement paraboliques par perturbation lisse de difféomorphismes présentant des tangences homoclines. Cette nouvelle preuve permet d'obtenir une version paramétrique de ce résultat
Scales
Get PDFWe introduce the notion of scale to generalize and compare different
invariants of metric spaces and their measures. Several versions of scales are
introduced such as Hausdorff, packing, box, local and quantization. They
moreover are defined for different growth, allowing in particular a refined
study of infinite dimensional spaces. We prove general theorems comparing the
different versions of scales. They are applied to describe geometries of
ergodic decompositions, of the Wiener measure and of functional spaces. The
first application solves a problem of Berger on the notions of emergence
(2020); the second lies in the geometry of the Wiener measure and extends the
work of Dereich-Lifshits (2005); the last refines Kolmogorov-Tikhomirov (1958)
study on functional spaces
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