1,720,966 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
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
Schwarz domain decomposition for the convected Helmholtz equation: analysis of transmission conditions
No full textInternational audienceWe investigate the convergence of optimized Schwarz methods (OSM) for the convected Helmholtz equation posed in unbounded domains. Unlike Helmholtz problems, the presence of a background flow introduces complex advection that makes both the analysis and the design of efficient transmission conditions challenging. In this note, we perform a convergence analysis and propose suitable transmission conditions that balance accuracy and computational efficiency. We also highlight how transmission conditions based on perfectly matched layers (PML) can be adapted to the convected setting. We hope this work will help the development of OSM for other time-harmonic problems with anisotropy
Conditions aux limites non-réfléchissantes et méthodes de décomposition de domaine pour l'acoustique industrielle en présence d'écoulement
No full textThis PhD project is devoted to non-overlapping Schwarz domain decomposition methods for the resolution of high frequency flow acoustics problems of industrial relevance. Time-harmonic solvers are difficult to parallelize due to their high-oscillatory behaviour, and current solvers quickly reach an upper frequency limit dictated by the available computer memory. Non-overlapping Schwarz methods split the domain into subdomains at the continuous level and provide a suitable setting for distributed memory parallelization. The problem is solved iteratively on the interface unknowns, where the keystone for quick convergence relies on appropriate transmission conditions. The first part of this thesis is devoted to the design of transmission operators tailored to convected and heterogeneous time-harmonic wave propagation. To this end we study two non-reflecting boundary techniques that provide local approximations to the Dirichlet-to-Neumann operator. On the one hand, Absorbing Boundary Conditions are designed based on microlocal analysis and pseudodifferential calculus. On the other hand, the convected acoustic stability issue is addressed for Perfectly Matched Layers in convex domains with Lorentz transformation. The second part of this thesis describes how to adapt a generic domain decomposition framework to flow acoustics, and applies the newly designed transmission conditions to simple academic problems. We explain the relation between the non-overlapping Schwarz formulation and an algebraic block LU factorization of the problem. Finally we propose a parallel implementation of the method and show the benefit of the approach for the three-dimensional noise radiation of a high by-pass ratio turbofan engine intake.Ce travail de thèse est consacré aux méthodes de décomposition de domaine de Schwarz sans recouvrement pour la résolution de problèmes industriels hautes fréquences d'acoustique en écoulement. Les méthodes de résolution en régime harmonique sont difficiles à paralléliser en raison de leur caractère oscillatoire, si bien que les méthodes actuelles sont limitées par une fréquence maximale, imposée par la mémoire disponible de l'ordinateur. Les méthodes de Schwarz sans recouvrement divisent le domaine en sous-domaines d'un point de vue continu et fournissent un cadre approprié en vue d'une parallélisation à mémoire distribuée. Le problème est résolu de manière itérative sur les inconnues d'interface, où la convergence rapide repose sur des conditions de transmission appropriées. La première partie de cette thèse est consacrée à la conception d'opérateurs de transmission adaptés à la propagation d'ondes harmoniques en milieu convecté et hétérogène. Dans ce cadre nous étudions deux catégories de conditions aux limites non-réfléchissantes qui fournissent des approximations locales de l'opérateur Dirichlet-to-Neumann. Dans un premier temps, des conditions aux limites absorbantes sont conçues basées sur l'analyse microlocale et le calcul pseudodifférentiel. Dans un second temps, la problématique de la stabilité acoustique en écoulement des couches parfaitement adaptées est abordée pour des domaines convexes par la transformation de Lorentz. La deuxième partie de cette thèse étend une méthode générique de décomposition de domaine à des problèmes d'acoustique en écoulement, et applique les conditions de transmission préalablement étudiées à des problèmes académiques simples. Nous expliquons le lien entre la méthode de Schwarz sans recouvrement et une factorisation algébrique LU par blocs du problème. Enfin, nous proposons une mise en œuvre parallèle et montrons l'intérêt de l'approche au rayonnement acoustique tridimensionnel de l'avant d'un turboréacteur d'avion
Schwarz domain decomposition for the convected Helmholtz equation: analysis of transmission conditions
No full textInternational audienceWe investigate the convergence of optimized Schwarz methods (OSM) for the convected Helmholtz equation posed in unbounded domains. Unlike Helmholtz problems, the presence of a background flow introduces complex advection that makes both the analysis and the design of efficient transmission conditions challenging. In this note, we perform a convergence analysis and propose suitable transmission conditions that balance accuracy and computational efficiency. We also highlight how transmission conditions based on perfectly matched layers (PML) can be adapted to the convected setting. We hope this work will help the development of OSM for other time-harmonic problems with anisotropy
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