1,720,977 research outputs found
Tests de comparaison de deux populations et statistiques de balayage spatial pour données fonctionnelles
No full textIn this thesis, we focus on the statistical comparison tests of two samples based on ranks on the one hand and the cluster detection method based on spatial scan statistics on the other hand. In both cases, the work was performed using functional data. The goal is to extend the methods developed in the univariate case, i.e. for R-valued random variables to the functional case, i.e. by using random variables valued in functional space. In the first part of this thesis, we study the median test based on ranks in the univariate case. We propose an extension of this latter for functional data. Then, we study the asymptotic behavior of its statistic under the null hypothesis. This extension is compared to other existing parametric and nonparametric statistics using simulated and real data to study its performance. In the second part, we introduce a nonparametric spatial scan statistic for functional data. It is derived from the Wilcoxon-Mann-Whitney statistic defined in an Hilbert space. The proposed scan method is applied on simulated data to study its performance, then on real data to extract characteristics of the demographic evolution of the Spanish population. In the last part, we develop an R package called HDSpatialScan. It allows to apply spatial scan statistics developed recently for functional data including the nonparametric scan statistic that we developed in this thesis. This package facilitates the use of the scanning methods and allows to plot the detected clusters with a simple and fast manner.Dans cette thèse, nous nous focalisons d'un côté sur les tests statistiques de comparaison de deux échantillons basés sur les rangs et d'un autre côté sur la méthode de détection d'agrégats basée sur les statistiques de balayage spatial. Dans les deux cas, le travail a été effectué en utilisant des données fonctionnelles. L'objectif est d'étendre les méthodes développées dans le cadre univarié c'est-à-dire à destination des variables aléatoires à valeurs dans R au cadre fonctionnel c'est-à-dire en utilisant des variables aléatoires à valeurs dans un espace fonctionnel. Dans la première partie, nous étudions le test de la médiane basé sur les rangs dans le cadre univarié. Nous proposons ensuite une extension de ce dernier pour des données fonctionnelles. Puis, nous étudions le comportement asymptotique de sa statistique sous l'hypothèse nulle. Cette extension est comparée à d’autres statistiques paramétriques et non paramétriques existantes en utilisant des données simulées et des données réelles pour étudier sa puissance. Dans la deuxième partie, nous introduisons une statistique de balayage spatial non paramétrique pour des données fonctionnelles. Cette statistique est dérivée de celle de Wilcoxon-Mann-Whitney définie dans un espace de Hilbert. La méthode de balayage proposée est appliquée sur des données simulées pour évaluer sa performance, ensuite sur des données réelles pour extraire des caractéristiques de l’évolution démographique de la population espagnole. Dans la dernière partie, nous développons un package R intitulé HDSpatialScan. Il permet d'appliquer les statistiques de balayage spatial récemment développées pour des données fonctionnelles, y compris la statistique de balayage introduite dans cette thèse. Ce package facilite l'utilisation des méthodes de balayage et permet de visualiser les agrégats détectés d'une manière simple et rapide
Comparison tests of two populations and spatial scan statistics for functional data
No full textDans cette thèse, nous nous focalisons d'un côté sur les tests statistiques de comparaison de deux échantillons basés sur les rangs et d'un autre côté sur la méthode de détection d'agrégats basée sur les statistiques de balayage spatial. Dans les deux cas, le travail a été effectué en utilisant des données fonctionnelles. L'objectif est d'étendre les méthodes développées dans le cadre univarié c'est-à-dire à destination des variables aléatoires à valeurs dans R au cadre fonctionnel c'est-à-dire en utilisant des variables aléatoires à valeurs dans un espace fonctionnel. Dans la première partie, nous étudions le test de la médiane basé sur les rangs dans le cadre univarié. Nous proposons ensuite une extension de ce dernier pour des données fonctionnelles. Puis, nous étudions le comportement asymptotique de sa statistique sous l'hypothèse nulle. Cette extension est comparée à d’autres statistiques paramétriques et non paramétriques existantes en utilisant des données simulées et des données réelles pour étudier sa puissance. Dans la deuxième partie, nous introduisons une statistique de balayage spatial non paramétrique pour des données fonctionnelles. Cette statistique est dérivée de celle de Wilcoxon-Mann-Whitney définie dans un espace de Hilbert. La méthode de balayage proposée est appliquée sur des données simulées pour évaluer sa performance, ensuite sur des données réelles pour extraire des caractéristiques de l’évolution démographique de la population espagnole. Dans la dernière partie, nous développons un package R intitulé HDSpatialScan. Il permet d'appliquer les statistiques de balayage spatial récemment développées pour des données fonctionnelles, y compris la statistique de balayage introduite dans cette thèse. Ce package facilite l'utilisation des méthodes de balayage et permet de visualiser les agrégats détectés d'une manière simple et rapide.In this thesis, we focus on the statistical comparison tests of two samples based on ranks on the one hand and the cluster detection method based on spatial scan statistics on the other hand. In both cases, the work was performed using functional data. The goal is to extend the methods developed in the univariate case, i.e. for R-valued random variables to the functional case, i.e. by using random variables valued in functional space. In the first part of this thesis, we study the median test based on ranks in the univariate case. We propose an extension of this latter for functional data. Then, we study the asymptotic behavior of its statistic under the null hypothesis. This extension is compared to other existing parametric and nonparametric statistics using simulated and real data to study its performance. In the second part, we introduce a nonparametric spatial scan statistic for functional data. It is derived from the Wilcoxon-Mann-Whitney statistic defined in an Hilbert space. The proposed scan method is applied on simulated data to study its performance, then on real data to extract characteristics of the demographic evolution of the Spanish population. In the last part, we develop an R package called HDSpatialScan. It allows to apply spatial scan statistics developed recently for functional data including the nonparametric scan statistic that we developed in this thesis. This package facilitates the use of the scanning methods and allows to plot the detected clusters with a simple and fast manner
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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