1,720,959 research outputs found
Reduced measure, large solutions and singularities for some parabolic problems
No full textCette thèse est constituée de trois parties. La première est consacrée à dégager les notions de "bonne mesure" et de "mesure réduite" pour deux problèmes paraboliques non linéaires. Pour chacun de ces problèmes et suite à un phénomène de relaxation, on construit une suite qui converge vers la plus "grande" sous-solution du problème donné. En plus, on cherche des "capacités universelles" et on établit des équivalences avec des mesures de Hausdorff. Dans la deuxième partie, on cherche des conditions d'existence et d'unicité de "grande solutions" pour des problèmes paraboliques dont le terme non linéaire est un terme d'absorption. Des conditions sur le bord du domaine permettent de prouver l'unicité de la solution. Dans la troisième partie, on étudie les "singularités" de deux problèmes paraboliques non linéaires.The thesis at hand is composed of three parts. The first part is devoted to present the notions of "good measure" and "reduced measure" for two non-linear parabolic problems. For each of these problems we construct a sequence, after a relaxation phenomenon, which converges to the "greatest" sub-solution of the given problem. Moreover, we look for "universal capacities" and we establish equivalence with Hausdorff measure. In the second part, we establish existence and uniqueness conditions for "large solutions" of parabolic problems whose non-linear term is an absorption one. Some boundary conditions will permit to prove uniqueness of solutions. In the last part we study the "singularities" of two non-linear parabolic problems
Mesures réduites, grandes solutions et singularités de quelques problèmes paraboliques
No full textCette thèse est constituée de trois parties. La première est consacrée à dégager les notions de "bonne mesure" et de "mesure réduite" pour deux problèmes paraboliques non linéaires. Pour chacun de ces problèmes et suite à un phénomène de relaxation, on construit une suite qui converge vers la plus "grande" sous-solution du problème donné. En plus, on cherche des "capacités universelles" et on établit des équivalences avec des mesures de Hausdorff. Dans la deuxième partie, on cherche des conditions d'existence et d'unicité de "grande solutions" pour des problèmes paraboliques dont le terme non linéaire est un terme d'absorption. Des conditions sur le bord du domaine permettent de prouver l'unicité de la solution. Dans la troisième partie, on étudie les "singularités" de deux problèmes paraboliques non linéaires.The thesis at hand is composed of three parts. The first part is devoted to present the notions of "good measure" and "reduced measure" for two non-linear parabolic problems. For each of these problems we construct a sequence, after a relaxation phenomenon, which converges to the "greatest" sub-solution of the given problem. Moreover, we look for "universal capacities" and we establish equivalence with Hausdorff measure. In the second part, we establish existence and uniqueness conditions for "large solutions" of parabolic problems whose non-linear term is an absorption one. Some boundary conditions will permit to prove uniqueness of solutions. In the last part we study the "singularities" of two non-linear parabolic problems.TOURS-Bibl.électronique (372610011) / SudocSudocFranceF
Initial trace of solutions of semilinear heat equation with absorption
No full textNonlinear Analysis, T. M. & A. Volume 93, 197-225 (2013).We study the initial trace problem for positive solutions of semilinear heat equations with strong absorption. We show that in general this initial trace is an outer regular Borel measure. We emphasize in particular the case where satisfies (E) , with and and prove that in the subcritical case $
On uniqueness of large solutions of nonlinear parabolic equations in nonsmooth domains
No full text16 pagesInternational audienceWe study the existence and uniqueness of the positive solutions of the problem (P): (q>1) in , on and , when is a bounded domain in . We construct a maximal solution, prove that this maximal solution is a large solution whenever $
Initial trace of solutions of semilinear heat equation with absorption
No full textNonlinear Analysis, T. M. & A. Volume 93, 197-225 (2013).We study the initial trace problem for positive solutions of semilinear heat equations with strong absorption. We show that in general this initial trace is an outer regular Borel measure. We emphasize in particular the case where satisfies (E) , with and and prove that in the subcritical case $
Solutions of some nonlinear parabolic equations with initial blow-up
No full textInternational audienceWe study the existence and uniqueness of solutions of () in where is a domain with a compact boundary, subject to the conditions on and the initial condition . By means of Brezis' theory of maximal monotone operators in Hilbert spaces, we construct a minimal solution when , whatever is the regularity of the boundary of the domain. When satisfies the parabolic Wiener criterion and is continuous, we construct a maximal solution and prove that it is the unique solution which blows-up at
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
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