24 research outputs found
Semilinear heat equation with singular terms
The main goal of this paper is to analyze the existence and nonexistence as well as the regularity of positive solutions for the following initial parabolic problem âtu â âu = ” u |x| 2 f u in âŠT := ⊠à (0, T), u = 0 on â⊠à (0, T), u(x, 0) = u0(x) in âŠ, where ⊠â RN, N â„ 3, is a bounded open, Ï â„ 0 and ” > 0 are real constants and f â L m(âŠT), m â„ 1, and u0 are nonnegative functions. The study we lead shows that the existence of solutions depends on Ï and the summability of the datum f as well as on the interplay between ” and the best constant in the Hardy inequality. Regularity results of solutions, when they exist, are also provided. Furthermore, we prove uniqueness of finite energy solutions
Vers une accĂ©lĂ©ration performante des applications de traitement dâimages sur architectures parallĂšles
Les systĂšmes parallĂšles et distribuĂ©s sont devenus, depuis quelques annĂ©es, des incontournables issues pour le domaine du calcul de haute performance. Selon les problĂšmes et les contextes considĂ©rĂ©s, plusieurs architectures parallĂšles et techniques algorithmiques de distribution de donnĂ©es et de traitements sont apparus. Dans ce papier nous nous proposons, Ă travers une revue de littĂ©rature et un retour dâexpĂ©rience, quelques aspects fondamentaux liĂ©s aux diffĂ©rents enjeux mis au cours de cette transformation de paradigme sĂ©quentiel-parallĂšle ainsi que les diffĂ©rentes contraintes auxquels la communautĂ© technique et scientifique doit vaincre. Lâaccent est mis sur les applications et les algorithmes de traitement dâimages accĂ©lĂ©rĂ©s via des architectures parallĂšles de type GPU. Une validation concrĂšte, Ă travers une Ă©tude comparative de performances de trois algorithmes de classification floue appliquĂ©s Ă la segmentation dâimages mĂ©dicales, est prĂ©sentĂ©
Existence of bounded solutions for nonlinear degenerate elliptic equations in Orlicz spaces
We prove the existence of bounded solutions for the nonlinear elliptic problem with , where and is a continuous monotone decreasing function with unbounded primitive. As regards the -function , no -condition is needed