1,720,971 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
Méthodes de Krylov pour l'algèbre linéaire et implémentation polymorphe
Get PDFRÉSUMÉ: Ce projet de recherche se situe à la frontière entre les mathématiques appliquées et l’informatique théorique. Il dépend du domaine de l’algèbre linéaire numérique et se focalise sur le développement d’algorithmes de résolution de systèmes linéaires. Dans notre cadre d’étude, les algorithmes de résolution sont itératifs, c’est-à-dire qu’ils génèrent une suite de solutions approximatives. Ces itérés sont construits de telle sorte qu’ils résident dans un espace de Krylov. Un espace de Krylov est généré par le produit répété d’une matrice à un vecteur initial. Un exemple d’espace de Krylov est l’ensemble des combinaisons linéaires de b, Ab et A2b. Les algorithmes ayant cette propriété sont considérés comme des méthodes de Krylov. Les recherches résumées dans ce document se décomposent en deux composantes. La première est théorique et englobe le développement d’un nouveau processus de Krylov appelé Ortho-gonal Hessenberg Reduction ainsi que huit nouvelles méthodes de Krylov (BiLQ, BiLQR, TriLQR, TriCG, TriMR, Gpmr, MinAres, cAr), mieux adaptées aux caractéristiques de certains systèmes linéaires. La seconde, axée sur l’aspect logiciel, concerne l’implémentation générique et modulaire de ces nouveaux algorithmes. Ces implémentations doivent s’adapter à divers domaines d’applications, incluant différents modes de stockage et de modélisation sur ordinateur. Un système linéaire peut être stocké avec différentes précisions machine, telles que simple, double ou quadruple précision, être résolu sur CPU ou GPU, ou encore être représenté dans différents formats de matrices, qu’elles soient creuses ou denses. Ces aspects soulignent la nécessité d’une implémentation polymorphe pour s’adapter à ces multiples configurations. Une implémentation polymorphe se réfère à la capacité d’un code informatique à traiter des paramètres de manière flexible, en leur permettant d’adopter différentes formes ou types en fonction du contexte. Ces travaux sont rassemblés dans la bibliothèque numérique Krylov.jl, implémentée dans le langage de programmation Julia. Ce langage de programmation est adéquat au projet en rai-son de sa fonctionnalité de dispatch multiple ; un mécanisme informatique permettant d’écrire une fonction une seule fois, et voir celle-ci compilée à la volée pour différentes configurations suivant le type des arguments. Krylov.jl s’est illustré pour résoudre des systèmes linéaires creux sur les deux supercalculateurs les plus puissants du monde, Frontier du laboratoire national d’Oak Ridge et Aurora du laboratoire national d’Argonne. Il offre la portabilité nécessaire aux nouvelles architectures des cartes graphiques AMD et Intel, respectivement présentes dans Frontier et Aurora. ABSTRACT: This research project lies at the intersection of applied mathematics and computer science. It is based on numerical linear algebra and focuses on the development of algorithms for solving linear systems. In our framework, the algorithms are iterative, meaning that they generate a sequence of approximate solutions. These iterates are built such that they lie in a Krylov subspace. A Krylov subspace is generated by the repeated product of a matrix to an initial vector. An example of a Krylov space is the set of linear combinations of b, Ab, and A2b. The algorithms with this property are Krylov methods. The research summarized in this document consists of two components. The first is theoretical and encompasses the development of a new Krylov process called Orthogonal Hessenberg Reduction as well as eight new Krylov methods (BiLQ, BiLQR, TriLQR, TriCG, TriMR, Gpmr, MinAres, cAr), better suited to the characteristics of certain linear systems. The second, focusing on the software aspect, concerns the generic and mod-ular implementation of these new algorithms. These implementations must adapt to various application domains, including different modeling and computer storage. A linear system may be stored with different machine precisions, such as single, double, or quadruple precision, solved on CPU or GPU, or represented in different matrix formats, whether sparse or dense. These aspects highlight the need for a polymorphic implementation to adapt to these multiple configurations. A polymorphic implementation refers to the ability of a com-puter code to handle parameters flexibly, allowing them to take on different forms or types depending on the context. These works are consolidated in the numerical library Krylov.jl, implemented in the Julia programming language. This programming language is suitable for the project due to its multiple dispatch feature; a mechanism that allows writing a function only once and having it compiled on-the-fly for different configurations depending on the types of the arguments. Krylov.jl has showcased its capabilities in solving sparse linear systems on world’s two most powerful supercomputers, Frontier at the Oak Ridge National Laboratory and Aurora at the Argonne National Laboratory. It provides portability to the new architectures of AMD and Intel graphics cards, present respectively in Frontier and Aurora
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
- …
