1,721,077 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
Opérations élémentaires sur courbes splines cubiques en deux dimensions
No full textnouvelle version: correction d'une erreur dans les équations (4) et (5).Brève description des opérations élémentaires associées aux courbes splines: création à partir d'un nuage de points quelconque, projection orthogonale sur la spline (détection du point de la spline le plus proche pour tout point du plan) et projection sur la spline dans une direction quelconque. Les codes Matlab associés à chaque exemple sont fournis dans le corps du texte
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
Simulation de l'interaction rotor/stator pour des turbo-machines aéronautiques en configuration non-accidentelle
Get PDFVersion adaptée TELDesigners have long time worked for a better efficiency of aircraft engines and one of the main challenges lies in minimizing the clearance between the rotating and stationary parts. This technology directly affects the vibratory response of aircraft engines and consequently contributes to the ignition of contacts between the blades tips and surrounding casings. If contact occurs on several simultaneous locations over the casing, specific phenomena may occur such as modal interaction. This study focuses on detecting this potentially dangerous phenomenon in an industrial framework. Because of the large number of degrees of freedom, component mode synthesis methods are considered: a fixed-interface one – namely the Craig-Bampton method – and a free-interface one – namely the Craig-Martinez method. The use of these methods in a contact framework is investigated. First, modal interaction phenomena are explored with simplified 2D models, analyzing the influence of kinematic restrictions on its detection. Then, 3D industrial models are used for which the "true" solution cannot be performed. Contact treatment involves bicubic uniform B-spline surfaces for a better numericla behavior of the solution algorithm. Results obtained with both Craig-Bampton and Craig-Martinez methods are compared in order to evaluate the most appropriate method for industrial applications such as the one presented in the appendices of the thesis.Dans le cadre de la conception de turbo-machines aéronautiques, l'amélioration du rendement est assurée, entre autres, par la diminution du jeu fonctionnel entre les parties tournantes et statiques, telles que les roues aubagées et le carter qui les entoure. Cette stratégie a des conséquences sur le comportement vibratoire des turbo-machines en favorisant l'apparition de contacts structuraux entre les sommets d'aubes et le carter, par exemple. Lorsque plusieurs points de contact co-existent, des phénomènes d'interaction modale peuvent apparaître. La simulation de ces phénomènes, potentiellement dangereux, dans un cadre indutriel est au cœur de notre étude. Du fait de la dimension du problème à traiter, des méthodes de réduction modale sont utilisées : une méthode à interfaces fixes, la méthode de Craig-Bampton, et une méthode à interfaces libres, la méthode de Craig-Martinez. L'étude porte notamment sur la performance de ces méthodes de réduction lorsqu'elles sont associées à une non linéarité de type contact. Le phénomène d'interaction modale est tout d'abord étudié sur des modèles 2D simplifiés avec l'analyse de la sensibilité des régimes d'interaction à la taille des modèles réduits, puis sur les modèles 3D industriels pour lesquels la solution vraie n'est pas accessible. La gestion du contact dans le 3D fait appel aux B-splines bicubiques surfaciques afin d'assurer de meilleures propriétés à la surface de contact et de faciliter la résolution numérique. Les résultats obtenus à l'aide des deux méthodes de réduction modale sont comparés et permettent de déterminer la méthode la plus appropriée pour l'industrialisation du code présentée en annexe de ce mémoire
Opérations élémentaires sur courbes splines cubiques en deux dimensions
No full textnouvelle version: correction d'une erreur dans les équations (4) et (5).Brève description des opérations élémentaires associées aux courbes splines: création à partir d'un nuage de points quelconque, projection orthogonale sur la spline (détection du point de la spline le plus proche pour tout point du plan) et projection sur la spline dans une direction quelconque. Les codes Matlab associés à chaque exemple sont fournis dans le corps du texte
Opérations élémentaires sur courbes splines cubiques en deux dimensions
No full textnouvelle version: correction d'une erreur dans les équations (4) et (5).Brève description des opérations élémentaires associées aux courbes splines: création à partir d'un nuage de points quelconque, projection orthogonale sur la spline (détection du point de la spline le plus proche pour tout point du plan) et projection sur la spline dans une direction quelconque. Les codes Matlab associés à chaque exemple sont fournis dans le corps du texte
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