1,721,080 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
Reduced model and inverse methods: Thermal performance of elementary components/ optimal composition materials
No full textOne of the main goals of the research centre of Lafarge is to establish their innovating materials in the building market of emerging countries.
For this purpose, is necessary to study the advantages and added values that these materials can provide to constructions.
The objective of this thesis is to create a parametric model which serves to evaluate the contribution of these materials to the dwellings energy performance, specially their impact on building’s thermal inertia.
The project has been structured in 4 parts: bibliography, TRNSYS simulation model and study 1 and study 2.
The purpose of the bibliography is to understand thermal inertia concept, its contribution to construction materials and its effect on buildings energy performance.
The objective of the second part is to describe the process followed to design and validate the parametric model, including the hypotheses done.
In Study 1the impact that non load baring walls have on building’s thermal inertia, will be evaluated with the TRNSYS model .The study will be focused in wet hot climates, specifically in Mumbai (India) and Rio de Janeiro (Brazil).
Study 2 is a world analysis done with the TRNSYS model to determine in which climates a better energy performance is achieved by using Lafarge’s materials.Outgoin
Reduced model and inverse methods: Thermal performance of elementary components/ optimal composition materials
No full textOne of the main goals of the research centre of Lafarge is to establish their innovating materials in the building market of emerging countries.
For this purpose, is necessary to study the advantages and added values that these materials can provide to constructions.
The objective of this thesis is to create a parametric model which serves to evaluate the contribution of these materials to the dwellings energy performance, specially their impact on building’s thermal inertia.
The project has been structured in 4 parts: bibliography, TRNSYS simulation model and study 1 and study 2.
The purpose of the bibliography is to understand thermal inertia concept, its contribution to construction materials and its effect on buildings energy performance.
The objective of the second part is to describe the process followed to design and validate the parametric model, including the hypotheses done.
In Study 1the impact that non load baring walls have on building’s thermal inertia, will be evaluated with the TRNSYS model .The study will be focused in wet hot climates, specifically in Mumbai (India) and Rio de Janeiro (Brazil).
Study 2 is a world analysis done with the TRNSYS model to determine in which climates a better energy performance is achieved by using Lafarge’s materials.Outgoin
Reduced model and inverse methods: Thermal performance of elementary components/ optimal composition materials
No full textOne of the main goals of the research centre of Lafarge is to establish their innovating materials in the building market of emerging countries.
For this purpose, is necessary to study the advantages and added values that these materials can provide to constructions.
The objective of this thesis is to create a parametric model which serves to evaluate the contribution of these materials to the dwellings energy performance, specially their impact on building’s thermal inertia.
The project has been structured in 4 parts: bibliography, TRNSYS simulation model and study 1 and study 2.
The purpose of the bibliography is to understand thermal inertia concept, its contribution to construction materials and its effect on buildings energy performance.
The objective of the second part is to describe the process followed to design and validate the parametric model, including the hypotheses done.
In Study 1the impact that non load baring walls have on building’s thermal inertia, will be evaluated with the TRNSYS model .The study will be focused in wet hot climates, specifically in Mumbai (India) and Rio de Janeiro (Brazil).
Study 2 is a world analysis done with the TRNSYS model to determine in which climates a better energy performance is achieved by using Lafarge’s materials.Outgoin
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
Interaction rupture-buckling, the case of the "splitting" of metal tube : experimental and numerical approach
No full textLorsqu’on découpe un feuillard à l’aide d’un outil, ou lorsqu’on découpe un tube selon son axe, au fur et à mesure que l’on propage la fissure qui traduit la découpe il arrive que des ondulations de flambage perturbent les deux bords libres générés par la propagation de la fissure. Cette étude vise à analyser les origines de ces ondulations. Nous avons mené une campagne expérimentale, dans laquelle des tubes en acier inox avec différentes géométries (rayon/épaisseur) sont « découpés » selon une génératrice. Une instrumentation adéquate, couplant des mesures ponctuelles, à l’aide de jauges de déformation, et une méthode champ par corrélation d’image, nous a permis de correctement mettre en exergue la phénoménologie, en particulier les cinématiques induites à l’échelle géométrique de la fissure (front de fissure) ainsi qu’à l’échelle du tube, avec les longueurs d’onde de flambage observées à l’aval de la fissure. La modélisation numérique menée en non linéaire géométrique (flambage), matériau (déchirure ductile), et conditions aux limites (contact) est aussi abordée à l’aide du code de calcul Abaqus/Standard. Pour la gestion de la propagation de la fissure, deux modèles de rupture sont proposés. Le premier modèle dit zone cohésive est développé et implanté dans le code Abaqus via la subroutine UEL. Pour la deuxième modélisation, nous avons utilisé le modèle dit « d’endommagement ductile » du code Abaqus. La modélisation via des éléments massifs ou des éléments coques volumiques ainsi que l’utilisation de ces modèles de rupture permettent de corroborer les observations expérimentales. Ces travaux montrent que l’augmentation de la charge inhérente au déplacement de l’outil de « découpe », induit une extension dans la direction circonférentielle et donc une striction dans la direction radiale amenant finalement la rupture. Lors de la rupture, un « sillage plastique » apparait, relativement large, près et parallèle aux bords de la fissure. « Confiné » par les autres parties du tube qui restent élastiques, des contraintes de compression axiale résiduelles apparaissent dans ce sillage plastique, à l’aval de la fissure, leur intensité est suffisante pour produire les ondulations des bords libres qui traduisent un flambage local. Les contraintes résiduelles liées à l’opération de découpe induisent donc le flambage.When one uses a tool to cut a sheet metal, or a tube according to his axis, as one propagates the crack which translates cutting it arrives that undulations of buckling disturb the two free edges generated by the propagation of the crack. This study aims at analyzing the origins of this behavior. We conducted an experimental campaign, in which stainless steel tubes with various geometries (radius/thickness) are « cut out » according to a generator. An adequate instrumentation, coupling of specific measurements, using strain gauges, and a field method, by digital image correlation, allowed us accurately to put forward phenomenology, in particular the kinematics at the scale of the crack (ahead of crack tip) and at the level of tube, with the wavelengths of buckling observed at the downstream of the crack tip. The numerical modeling taking into account nonlinearities of material (ductile tear), geometry (buckling) and boundary conditions (contact) is also approached using the code Abaqus/Standard. For the management of the crack propagation, two rupture models are proposed. The first model called cohesive zone is developed and implemented in the Abaqus code via the user routine UEL. For the second modeling, we used the model called “ductile damage model” in the Abaqus code. Modeling via solid elements or shell continuum elements as well as the use of these rupture models make it possible to corroborate the experimental observations. These studies show that the increase of the load inherent in the displacement of the tool of « cutting » induced a circumferential extension of the tube that leads to a local necking in the radial direction bringing the rupture finally. During the failure, a “plastic wake” appears, relatively wide, close and parallel to crack lips. Constrained by other parts of the tube which remain elastic, sufficient axial residual compressive stresses produced in this plastic wake produce the undulations which represents a local buckling. The residual stresses related to the operation of cutting thus induce buckling
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