1,720,958 research outputs found
Etude de quelques équations aux dérivées partielles non linéaire sans compacité
No full textThe objective of this thesis is the study of some nonlinear partial differential equations on a regular bounded domain, which have a variational structure, and which present a compacitance defect. In this thesis, through the problems discussed in Chapters 2,3,4, we have shown how these difficulties can be overcome and we have also obtained new results concerning the existence and regularity of solutions. Specifically, in Chapter 2, we study a Dirichlet problem involving the operator Laplacian with weights, a critical nonlinearity in the Sobolev sense and a parameter We discuss results of existence and non-existence of solutions which depend, among other things, on the position of with respect to the dimension of the space on the behavior of the weight in the vicinity of its minima and on the parameter In chapter 3, we study a nonlinear minimization problem with two weakly coupled unknowns which gives rise to critical Sobolev exponents Using variational methodscombined with a perturbation method, we overcome the lack ofregularity of the energy functional and we prove the existence of solutions. Finally, in chapter 4 of this report, we consider a problem of minimization of certain types of nonlinear polyharmonic elliptic equations of the -th order involving an operator . We establish existence results of solutions and under suitable conditions on we obtain S_{\theta,r}(\varphi)< S_{0,r}(\varphi) and in other conditions, we obtain L’objectif de cette thèse est l’étude de quelques \'Equations aux d\'eriv\'ees partielles non-lin\'eaires sur un domaine borné régulier, qui sont à structure variationnelle, et qui présentent un défaut de compacit\'e. Dans cette thèse, à travers les problèmes abordés dans les Chapitres 2,3,4, nous avons montré comment ces difficulté peut être surmontée et nous avons obtenus également de nouveaux résultats concernant l'existence et la régularité de solutions. Précisément, dans le chapitre 2, nous étudions un problème de Dirichlet faisant intervenir l'opérateur Laplacien avec poids, une non-linéarité critique au sens de Sobolev et un paramètre Nous abordons des réultats d'existence et de non-existencede de solutions qui dépend, entre autre, de la position de par rapport à la dimension de l'espace de comportement du poids au voisinage de ses minima et du paramètre Dans le chapitre 3, nous étudions un problème de minimisation non linéaire à deux inconnus faiblement couplés qui fait apparaitre des exposants critiques de Sobolev. En utilisant des méthodes variationnellescombiné avec une méthode de perturbation, nous surmontons le manque derégularité de la fonctionnelle énergie et nous prouvons l’existence de solutions. Enfin, dans le chapitre 4 de ce rapport, nous considérons un problème de minimisation de certains types d'équations elliptiques polyharmoniques non linéaires du -ème ordre faisant intervenir un opérateur . Nous établissons des résultats d’existence de solutions et dans des conditions adaptées
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
A system with weights and with critical Sobolev exponent
No full textInternational audienceIn this paper, we investigate the minimization problem : inf u ∈ H 1 0 (Ω), v ∈ H 1 0 (Ω), u L q = 1, v L q = 1 1 2 Ω a(x)|∇u(x)| 2 dx + 1 2 Ω b(x)|∇v(x)| 2 dxλ Ω u(x)v(x)dx where q = 2N N-2 , N ≥ 4, a and b are two continuous positive weight functions. We show the existence of solutions of the previous minimizing problem under some conditions on a, b, the dimension of the space and the parameter λ
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
A system with weights and with critical Sobolev exponent
Full text linkIn this paper, we investigate the minimization problem : where , , and are two continuous positive weight functions. We show
the existence of solutions of the previous minimizing problem under some
conditions on , , the dimension of the space and the parameter
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