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P-adaptive Hermite methods for initial value problems∗

Ronald Chen, Thomas Hagstrom (2012)

ESAIM: Mathematical Modelling and Numerical Analysis

We study order-adaptive implementations of Hermite methods for hyperbolic and singularly perturbed parabolic initial value problems. Exploiting the facts that Hermite methods allow the degree of the local polynomial representation to vary arbitrarily from cell to cell and that, for hyperbolic problems, each cell can be evolved independently over a time-step determined only by the cell size, a relatively straightforward method is proposed. Its utility is demonstrated on a number of model problems...

P-adaptive Hermite methods for initial value problems

Ronald Chen, Thomas Hagstrom (2012)

ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique

We study order-adaptive implementations of Hermite methods for hyperbolic and singularly perturbed parabolic initial value problems. Exploiting the facts that Hermite methods allow the degree of the local polynomial representation to vary arbitrarily from cell to cell and that, for hyperbolic problems, each cell can be evolved independently over a time-step determined only by the cell size, a relatively straightforward method is proposed. Its utility is demonstrated on a number of model problems...

P-adaptive Hermite methods for initial value problems∗

Ronald Chen, Thomas Hagstrom (2012)

ESAIM: Mathematical Modelling and Numerical Analysis

We study order-adaptive implementations of Hermite methods for hyperbolic and singularly perturbed parabolic initial value problems. Exploiting the facts that Hermite methods allow the degree of the local polynomial representation to vary arbitrarily from cell to cell and that, for hyperbolic problems, each cell can be evolved independently over a time-step determined only by the cell size, a relatively straightforward method is proposed. Its utility is demonstrated on a number of model problems...

Peak solutions for an elliptic system of FitzHugh-Nagumo type

Edward Norman Dancer, Shusen Yan (2003)

Annali della Scuola Normale Superiore di Pisa - Classe di Scienze

The aim of this paper is to study the existence of various types of peak solutions for an elliptic system of FitzHugh-Nagumo type. We prove that the system has a single peak solution, which concentrates near the boundary of the domain. Under some extra assumptions, we also construct multi-peak solutions with all the peaks near the boundary, and a single peak solution with its peak near an interior point of the domain.

Perturbation antisymétrique et oscillations dans des équations paraboliques

Isabelle Gallagher (1998)

Journées équations aux dérivées partielles

L'objet de cet exposé est l'étude d'équations d'évolution de type parabolique, périodiques, que l'on pénalise par un terme linéaire, antisymétrique. Par application des méthodes de S. Schochet pour le cas hyperbolique, on obtient un développement asymptotique des solutions de telles équations. La méthode suivie consiste à étudier l'influence de fortes oscillations en temps dans des systèmes paraboliques. Cette théorie est appliquée à deux systèmes décrivant le comportement de fluides géophysiques,...

Phase field model for mode III crack growth in two dimensional elasticity

Takeshi Takaishi, Masato Kimura (2009)

Kybernetika

A phase field model for anti-plane shear crack growth in two dimensional isotropic elastic material is proposed. We introduce a phase field to represent the shape of the crack with a regularization parameter ϵ > 0 and we approximate the Francfort–Marigo type energy using the idea of Ambrosio and Tortorelli. The phase field model is derived as a gradient flow of this regularized energy. We show several numerical examples of the crack growth computed with an adaptive mesh finite element method.

Populational adaptive evolution, chemotherapeutic resistance and multiple anti-cancer therapies

Alexander Lorz, Tommaso Lorenzi, Michael E. Hochberg, Jean Clairambault, Benoît Perthame (2013)

ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique

Resistance to chemotherapies, particularly to anticancer treatments, is an increasing medical concern. Among the many mechanisms at work in cancers, one of the most important is the selection of tumor cells expressing resistance genes or phenotypes. Motivated by the theory of mutation-selection in adaptive evolution, we propose a model based on a continuous variable that represents the expression level of a resistance gene (or genes, yielding a phenotype) influencing in healthy and tumor cells birth/death...

Problème de Cauchy pour opérateurs locaux et «changement de temps»

Gunter Lumer (1975)

Annales de l'institut Fourier

Nous donnons, dans un cadre très général, des critères de résolubilité pour un certain type de problèmes de Cauchy, et des résultats (entre autres, de compacité) concernant les opérateurs associés à leur résolution. Puis nous considérons les perturbations singulières du type “changement de temps”, et obtenons des conditions suffisantes, et des critères nécessaires et suffisants (modulo prolongement, au besoin) de résolubilité pour le problème de Cauchy perturbé (perturbation d’un problème résoluble)....

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