1,720,964 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
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
Study of several problems linked to branching random walks and reinforced random walk
No full textDans cette thèse nous étudions des marches aléatoires branchantes spatiales critiques partant de processus ponctuels et un processus renforcé nommé VRJP. Nous donnons une nouvelle preuve de la caractérisation des mesures invariantes pour les marches branchantes spatiales en grande dimension. Par ailleurs, nous nous intéressons au comportement asymptotique d'une martingale associée au VRJP. Nous étudions également la densité d'état d'un opérateur de Schrödinger aléatoire lié au VRJP. De plus, en considérant des limites d'échelle du potentiel aléatoire associé au VRJP, nous fournissons une nouvelle preuve des propriétés de Matsumoto-Yor concernant des fonctionnelles exponentielles du mouvement Brownien. A l'aide des mêmes limites d'échelle, nous construisons une version continue de l'opérateur de Schrödinger associé au VRJP. Enfin, nous prouvons une version multidimensionnelle des propriétés de Matsumoto-Yor.In this thesis we study spatial critical branching random walks starting from point processes and a reinforced process called the VRJP. We give a new proof of the characterization of invariant measures for spatial branching random walks in high dimension. Moreover, we look at the asymptotic behaviour of some martingale which is related with the VRJP. We also study the density of states of a random Schrödinger operator which is associated with the VRJP. Furthermore, considering the scaling limits of a random potential which is linked to the VRJP, we give a new proof of Matsumoto-Yor properties regarding some exponential functionals of the Brownian motion. By means of these scaling limits, we also construct a continuous version of the Schrödinger operator associated with the VRJP. Finally, we prove a multidimensional version of the Matsumoto-Yor properties
Etude de quelques problèmes liés aux marches aléatoires branchantes et aux marches aléatoires renforcées
No full textIn this thesis we study spatial critical branching random walks starting from point processes and a reinforced process called the VRJP. We give a new proof of the characterization of invariant measures for spatial branching random walks in high dimension. Moreover, we look at the asymptotic behaviour of some martingale which is related with the VRJP. We also study the density of states of a random Schrödinger operator which is associated with the VRJP. Furthermore, considering the scaling limits of a random potential which is linked to the VRJP, we give a new proof of Matsumoto-Yor properties regarding some exponential functionals of the Brownian motion. By means of these scaling limits, we also construct a continuous version of the Schrödinger operator associated with the VRJP. Finally, we prove a multidimensional version of the Matsumoto-Yor properties.Dans cette thèse nous étudions des marches aléatoires branchantes spatiales critiques partant de processus ponctuels et un processus renforcé nommé VRJP. Nous donnons une nouvelle preuve de la caractérisation des mesures invariantes pour les marches branchantes spatiales en grande dimension. Par ailleurs, nous nous intéressons au comportement asymptotique d'une martingale associée au VRJP. Nous étudions également la densité d'état d'un opérateur de Schrödinger aléatoire lié au VRJP. De plus, en considérant des limites d'échelle du potentiel aléatoire associé au VRJP, nous fournissons une nouvelle preuve des propriétés de Matsumoto-Yor concernant des fonctionnelles exponentielles du mouvement Brownien. A l'aide des mêmes limites d'échelle, nous construisons une version continue de l'opérateur de Schrödinger associé au VRJP. Enfin, nous prouvons une version multidimensionnelle des propriétés de Matsumoto-Yor
A propos du comportement asymptotique de la martingale associée au processus de saut renforcé par sommets sur les arbres et Z d
No full textWe study the asymptotic behaviour of the martingale (ψ n (o)) n∈N associated with the Vertex Reinforced Jump Process (VRJP). We show that it is bounded in L p for every p > 1 on trees and uniformly integrable on Z d in all the transient phase of the VRJP. Moreover, when the VRJP is recurrent on trees, we have good estimates on the moments of ψ n (o) and we can compute the exact decreasing rate τ such that n −1 ln(ψ n (o)) ∼ −τ almost surely where τ is related to standard quantities for branching random walks. Besides, on trees, at the critical point, we show that n −1/3 ln(ψ n (o)) ∼ −ρ c almost surely where ρ c can be computed explicitely. Furthermore, at the critical point, we prove that the discrete process associated with the VRJP is a mixture of positive recurrent Markov chains. Our proofs use properties of the β-potential associated with the VRJP and techniques coming from the domain of branching random walks
About the asymptotic behaviour of the martingale associated with the Vertex Reinforced Jump Process on trees and Z d
Get PDFWe study the asymptotic behaviour of the martingale (ψ n (o)) n∈N associated with the Vertex Reinforced Jump Process (VRJP). We show that it is bounded in L p for every p > 1 on trees and uniformly integrable on Z d in all the transient phase of the VRJP. Moreover, when the VRJP is recurrent on trees, we have good estimates on the moments of ψ n (o) and we can compute the exact decreasing rate τ such that n −1 ln(ψ n (o)) ∼ −τ almost surely where τ is related to standard quantities for branching random walks. Besides, on trees, at the critical point, we show that n −1/3 ln(ψ n (o)) ∼ −ρ c almost surely where ρ c can be computed explicitely. Furthermore, at the critical point, we prove that the discrete process associated with the VRJP is a mixture of positive recurrent Markov chains. Our proofs use properties of the β-potential associated with the VRJP and techniques coming from the domain of branching random walks
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