1,721,064 research outputs found
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
L'étude de quelques problèmes d'optimisation de forme spectrale.
No full textNous étudions l'attitude de la solution du problème aux limites deWentzell-Laplace par rapport aux déformations de forme. D'une part, nous prouvons la continuité de la solution sous une déformation Lipschitz d'un problème de valeurs limites uniformément Lipschitz domaines dans l'espace euclidien R^d. D'autre part, nous démontrons la continuité de la solution sous la convergence W^{2,∞} des domaines de (2,∞)-Sobolev dans R^d. Après cela, nous discutons de la convergence de la fonction distance signée dans W^{1,p}(B) avec 1 ≤ p ≤ ∞ par rapport à la convergence de Hausdorff des domaines moins réguliers, où B est une grande boule contenant la séquence des domaines (Ω_{n})_{n∈N} et l'ensemble limite Ω, et on peut en déduire les résultats suivants: le cas uniformément Lipschitz suffit pour prouver la convergence de la différentielle du premier ordre dans L^p avec 1 ≤ p < ∞; alors que dans le cas p = ∞, nous devons supposer une régularité plus importante, qui est celle de la "positive reach". De plus, pour prouver la convergence de la différentielle du premier ordre de la fonction de projection sur ∂Ω_{n} dans L^p avec 1 ≤ p ≤ ∞, nous devons injecter la régularité de (2,∞)-Sobolev avec la nécessité de convergence W^{2,∞} de ces domaines.Ensuite on considère le problème de valeurs propres associé. Afin d'illustrer le comportement du spectre, nous considérons un exemple explicite sur la boule dans R^2, où nous trouvons explicitement les valeurs propres et leurs fonctions propres correspondantes. Après avoir montré l'analyticité des valeurs propres λ et de leurs fonctions propres correspondantes u dans un voisinage ouvert de t = 0, nous dérivons, au sens de Hadamard, les dérivées de forme du premier et du second ordre des valeurs propres à l'instant t = 0. Ensuite, nous montrons que la boule n'est pas une forme critique de ce problème de valeurs propres, avec et sans contrainte de volume. Enfin, en dimension deux, nous prouvons que, sous certaines contraintes et sous un champ de vecteurs de déformation V ∈ W ^{3,∞}(Ω_{0}, R^2), il n'y a pas de formes critiques pour ce problème de valeurs propres.Nous avons essayé de montrer que si nous avons une valeur propre multiple λ dans Ω, elle peut se diviser sous certaines déformations de la forme initiale. Enfin et surtout, nous discutons de la simplicité générique du spectre. Ces deux problèmes restent ouverts.We investigate the attitude of the solution of the Wentzell-Laplace boundary value problem with respect to shape deformations. On one hand, we prove the continuity of the solution under Lipschitz deformation of uniformly Lipschitz domains in the Euclidean space R^d. On the other hand, we demonstrate the continuity of the solution under the W^{2,∞} convergence of (2,∞)-Sobolev domains in R^d. After that, we discuss the convergence of the signed distance function in W^{1,p}(B) with 1 ≤ p ≤ ∞ with respect to the Hausdorff convergence of less regular domains, where B is a large ball containing the sequence of domains (Ω_{n})_{n∈N} and the limit set Ω, and we derive the following results: the uniformly Lipschitz case is enough for proving the convergence of the first order differential in L^p with 1 ≤ p < ∞; while in case p = ∞, we need to assume more regularity, the "positive reach" one. Moreover, to prove the convergence of the first order differential of the projection function on ∂Ω_{n} in L^p with 1 ≤ p ≤ ∞, we have to inject the (2,∞)-Sobolev regularity with the necessity of W^{2,∞} convergence of thesedomains.In a second step we consider the eigenvalues problem. In order to illustratethe behavior of the spectrum, we consider an explicit example about the ball in R^2, where we find explicitly the eigenvalues and their corresponding eigenfunctions. After showing the analyticity of the eigenvalues λ and their corresponding eigenfunctions u in an open neighborhood of t = 0, we derive, in the sense of Hadamard, the first and second-order shape derivatives of the eigenvalues at time t = 0. After that, we show that the ball is not a critical shape of this eigenvalue problem, with and without a volume constraint. Finally, in dimension two, we prove that, with some constraints and under a deformation vector field V ∈ W^{3,∞}(Ω_{0}, R^2), there are no critical shapes for this eigenvalue problem.Finally, we try to show that if we have a multiple eigenvalue λ in Ω, it can split under certain deformation of the initial shape. Last but not least, we discuss the generic simplicity of the spectrum. We provide reflections and elements of study for these two problems that remain open
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Location of an object immersed in a fluid
No full textCette thèse s’inscrit dans le domaine des mathématiques appelé optimisation de formes. Plus précisément, nous étudions ici un problème inverse de détection à l’aide du calcul de forme et de l’analyse asymptotique. L’objectif est de localiser un objet immergé dans un fluide visqueux, incompressible et stationnaire. Les questions principales qui ont motivé ce travail sont les suivantes :– peut-on détecter un objet immergé dans un fluide à partir d’une mesure effectuée à la surface ?– peut-on reconstruire numériquement cet objet, i.e. approcher sa position et sa forme, à partir de cette mesure ?– peut-on connaître le nombre d’objets présents dans le fluide en utilisant cette mesure ?Les résultats obtenus sont décrits dans les cinq chapitres de cette thèse :– le premier met en place un cadre mathématique pour démontrer l’existence des dérivées de forme d’ordre un et deux pour les problèmes de détection d’inclusions ;– le deuxième analyse le problème de détection à l’aide de l’optimisation géométrique de forme : un résultat d’identifiabilité est montré, le gradient de forme de plusieurs types de fonctionnelles de forme est caractérisé et l’instabilité de ce problème inverse est enfin démontrée ;– le chapitre 3 utilise nos résultats théoriques pour reconstruire numériquement des objets immergés dans un fluide à l’aide d’un algorithme de gradient de forme ;– le chapitre 4 analyse la localisation de petites inclusions dans un fluide à l’aide de l’optimisation topologique de forme : le gradient topologique d’une fonctionnelle de forme de Kohn-Vogelius est caractérisé ;– le dernier chapitre utilise cette dernière expression théorique pour déterminer numériquement le nombre et la localisation de petits obstacles immergés dans un fluide à l’aide d’un algorithme de gradient topologique.This dissertation takes place in the mathematic field called shape optimization. More precisely, we focus on a detecting inverse problem using shape calculus and asymptotic analysis. The aim is to localize an object immersed in a viscous, incompressible and stationary fluid. This work was motivated by the following main questions:– can we localize an obstacle immersed in a fluid from a boundary measurement?– can we reconstruct numerically this object, i.e. be close to its localization and its shape, from this measure?– can we know how many objects are included in the fluid using this measure?The results are described in the five chapters of the thesis:– the first one gives a mathematical framework in order to prove the existence of the shape derivatives oforder one and two in the frame of the detection of inclusions;– the second one analyzes the detection problem using geometric shape optimization: an identifiabilityresult is proved, the shape gradient of several shape functionals is characterized and the instability of thisinverse problem is proved;– the chapter 3 uses our theoretical results in order to reconstruct numerically some objets immersed in a fluid using a shape gradient algorithm;– the fourth chapter analyzes the detection of small inclusions in a fluid using the topological shape optimization : the topological gradient of a Kohn-Vogelius shape functional is characterized;– the last chapter uses this theoretical expression in order to determine numerically the number and the location of some small obstacles immersed in a fluid using a topological gradient algorithm
- …
