1,720,962 research outputs found
Espaces de chemins couplés pour le calcul de sensibilités par la méthode de Monte Carlo : opérationnalité et perspectives
No full textThis thesis focuses on physical quantities modeled in coupled path integrals, numerically evaluated through Monte Carlo statistical sampling. The concept of coupled paths, recently introduced, aims to address high-level phenomenological and geometric integration needs. Here, we consider multiple physics interacting within a system, with geometry composed of assemblies of numerous subsystems, each geometrically refined. Our study concentrates on the sensitivity of such a quantity to a model parameter. Specifically, we start from proposed methods for statistically estimating this sensitivity, utilizing the same coupled paths as those of the observable, and we test their operability. This operability is examined on three levels: feasibility in terms of implementation, statistical convergence, and the ability to exploit the estimated sensitivities for uncertainty propagation. The primary framework of this study is climatic, involving the estimation of radiative forcing related to changes in carbon dioxide concentration in the Earth's atmosphere. The coupled physics involved are radiative transfer and molecular spectroscopy. The descriptive complexity arises from the presence of a large number of absorption lines (due to all active rotation-vibration state transitions in the infrared frequencies), the thermodynamic state of the atmosphere at all altitudes worldwide, and its fluctuations at all scales over the duration of a climatic period.Cette thèse s'intéresse à des observables physiques modélisées sous forme d'intégrales de chemins couplés, évaluées numériquement par échantillonnage statistique de type Monte Carlo. Le concept de chemins couplés, récemment introduit, vise à répondre à des besoins d'intégration phénoménologique et géométrique élevés. Nous envisageons ici plusieurs physiques interagissant au sein d'un système, dont la géométrie est constituée d'assemblages de nombreux sous-systèmes, eux-mêmes géométriquement raffinés. Notre étude se concentre sur la sensibilité d'une telle observable à la valeur d'un paramètre de modélisation. Plus précisément, nous partons des propositions faites concernant l'estimation statistique de cette sensibilité, en exploitant les mêmes chemins couplés que ceux de l'observable, et nous en testons l'opérationnalité. Cette opérationnalité est examinée à trois niveaux : la praticabilité en termes de mise en œuvre, la convergence statistique, et la capacité à exploiter les sensibilités ainsi estimées pour la propagation d'incertitudes. Le cadre principal de cette étude est climatique, avec l'estimation du forçage radiatif lié au changement de concentration du dioxyde de carbone dans l'atmosphère terrestre. Les physiques couplées alors le transfert radiatif et la spectroscopie moléculaire. La complexité descriptive provient de la présence d'un grand nombre de raies d'absorption (en raison de toutes les transitions d'état de rotation-vibration actives aux fréquences infrarouges), de l'état thermodynamique de l'atmosphère à toutes les altitudes en tous les points du globe, et de ses fluctuations à toutes les échelles sur la durée d'une période climatique
Espaces de chemins couplés pour le calcul de sensibilités par la méthode de Monte Carlo : opérationnalité et perspectives
No full textThis thesis focuses on physical quantities modeled in coupled path integrals, numerically evaluated through Monte Carlo statistical sampling. The concept of coupled paths, recently introduced, aims to address high-level phenomenological and geometric integration needs. Here, we consider multiple physics interacting within a system, with geometry composed of assemblies of numerous subsystems, each geometrically refined. Our study concentrates on the sensitivity of such a quantity to a model parameter. Specifically, we start from proposed methods for statistically estimating this sensitivity, utilizing the same coupled paths as those of the observable, and we test their operability. This operability is examined on three levels: feasibility in terms of implementation, statistical convergence, and the ability to exploit the estimated sensitivities for uncertainty propagation. The primary framework of this study is climatic, involving the estimation of radiative forcing related to changes in carbon dioxide concentration in the Earth's atmosphere. The coupled physics involved are radiative transfer and molecular spectroscopy. The descriptive complexity arises from the presence of a large number of absorption lines (due to all active rotation-vibration state transitions in the infrared frequencies), the thermodynamic state of the atmosphere at all altitudes worldwide, and its fluctuations at all scales over the duration of a climatic period.Cette thèse s'intéresse à des observables physiques modélisées sous forme d'intégrales de chemins couplés, évaluées numériquement par échantillonnage statistique de type Monte Carlo. Le concept de chemins couplés, récemment introduit, vise à répondre à des besoins d'intégration phénoménologique et géométrique élevés. Nous envisageons ici plusieurs physiques interagissant au sein d'un système, dont la géométrie est constituée d'assemblages de nombreux sous-systèmes, eux-mêmes géométriquement raffinés. Notre étude se concentre sur la sensibilité d'une telle observable à la valeur d'un paramètre de modélisation. Plus précisément, nous partons des propositions faites concernant l'estimation statistique de cette sensibilité, en exploitant les mêmes chemins couplés que ceux de l'observable, et nous en testons l'opérationnalité. Cette opérationnalité est examinée à trois niveaux : la praticabilité en termes de mise en œuvre, la convergence statistique, et la capacité à exploiter les sensibilités ainsi estimées pour la propagation d'incertitudes. Le cadre principal de cette étude est climatique, avec l'estimation du forçage radiatif lié au changement de concentration du dioxyde de carbone dans l'atmosphère terrestre. Les physiques couplées alors le transfert radiatif et la spectroscopie moléculaire. La complexité descriptive provient de la présence d'un grand nombre de raies d'absorption (en raison de toutes les transitions d'état de rotation-vibration actives aux fréquences infrarouges), de l'état thermodynamique de l'atmosphère à toutes les altitudes en tous les points du globe, et de ses fluctuations à toutes les échelles sur la durée d'une période climatique
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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