m

F Nous contacter

0

Documents  Cohen, Albert | enregistrements trouvés : 13

O
     

-A +A

P Q

Déposez votre fichier ici pour le déplacer vers cet enregistrement.

Research talks;Analysis and its Applications;Partial Differential Equations

Ingrid Daubechies' construction of orthonormal wavelet bases with compact support published in 1988 started a general interest to employ these functions also for the numerical solution of partial differential equations (PDEs). Concentrating on linear elliptic and parabolic PDEs, I will start from theoretical topics such as the well-posedness of the problem in appropriate function spaces and regularity of solutions and will then address quality and optimality of approximations and related concepts from approximation the- ory. We will see that wavelet bases can serve as a basic ingredient, both for the theory as well as for algorithmic realizations. Particularly for situations where solutions exhibit singularities, wavelet concepts enable adaptive appproximations for which convergence and optimal algorithmic complexity can be established. I will describe corresponding implementations based on biorthogonal spline-wavelets.
Moreover, wavelet-related concepts have triggered new developments for efficiently solving complex systems of PDEs, as they arise from optimization problems with PDEs.
Ingrid Daubechies' construction of orthonormal wavelet bases with compact support published in 1988 started a general interest to employ these functions also for the numerical solution of partial differential equations (PDEs). Concentrating on linear elliptic and parabolic PDEs, I will start from theoretical topics such as the well-posedness of the problem in appropriate function spaces and regularity of solutions and will then address quality ...

65T60 ; 94A08 ; 65N12 ; 65N30 ; 49J20

... Lire [+]

Déposez votre fichier ici pour le déplacer vers cet enregistrement.


ISBN 978-0-8265-1357-1

Innovations and applied mathematics

Localisation : Colloque 1er étage (SAIN)

analyse numérique # approximation sur les variétés # conception assisté par ordinateur # courbe algébrique # espace de fonction # espace natif # graphique informatique # involution # ondelette # schème multi-résolution # spline # spline polyharmonique # surface algébrique # triangulation emboîtée

65-06 ; 65D17 ; 65D18

... Lire [+]

Déposez votre fichier ici pour le déplacer vers cet enregistrement.

- ix; 285 p.
ISBN 978-0-9728482-8-2

Modern methods in mathematics

Localisation : Colloque 1er étage (AVIG)

analyse numérique # analyse acoustique # détection de blobs # approximation conforme # différences divisées # interpolation d'Hermite # compression d'images # polynôme de Jacobi # théorie de l'apprentissage # théorie de Morse # B-spline paramétrique # spline polyharmonique # ondelettes polyharmonique # interpolation polynômiale # quasi-interpolants # interpolation rationnelle # superconvergence # spline # ondelettes

65-06 ; 00B25

... Lire [+]

Déposez votre fichier ici pour le déplacer vers cet enregistrement.

- xi; 402 p.
ISBN 978-0-9728482-1-3

Modern methods in mathematics

Localisation : Colloque 1er étage (SAIN)

subdivision bi-variée # spline cardinale # valeures propres diadiques # variétés homogènes # compression d'images # subdivision # spline polyharmonique # équation de poisson # quasi-interpolants # fonction basique radiale # ondelettes

65-06 ; 41-06 ; 65D17 ; 65D18

... Lire [+]

Déposez votre fichier ici pour le déplacer vers cet enregistrement.

- x; 748 p.
ISBN 978-3-642-27412-1

Lecture notes in computer science , 6920

Localisation : Collection 1er étage

analyse numérique # CAO # analyse d'image # géométrie

65-06 ; 65D17 ; 65D18 ; 00B25

... Lire [+]

Déposez votre fichier ici pour le déplacer vers cet enregistrement.

- 161 p.
ISBN 978-3-540-20099-4

Lecture notes in mathematics , 1825

Localisation : Collection 1er étage

analyse numérique # analyse multiéchelle # ondelette # approximation non-linéaire # éléments finis # méthode des éléments finis # simulation

82D37 ; 80A17 ; 65L05

... Lire [+]

Déposez votre fichier ici pour le déplacer vers cet enregistrement.

Research talks

Multigrid is an iterative method for solving large linear systems of equations whose Toeplitz system matrix is positive definite. One of the crucial steps of any Multigrid method is based on multivariate subdivision. We derive sufficient conditions for convergence and optimality of Multigrid in terms of trigonometric polynomials associated with the corresponding subdivision schemes.
(This is a joint work with Marco Donatelli, Lucia Romani and Valentina Turati).
Multigrid is an iterative method for solving large linear systems of equations whose Toeplitz system matrix is positive definite. One of the crucial steps of any Multigrid method is based on multivariate subdivision. We derive sufficient conditions for convergence and optimality of Multigrid in terms of trigonometric polynomials associated with the corresponding subdivision schemes.
(This is a joint work with Marco Donatelli, Lucia Romani and ...

65N55 ; 65N30 ; 65F10 ; 65F35

... Lire [+]

Déposez votre fichier ici pour le déplacer vers cet enregistrement.

Research talks;Control Theory and Optimization

90Cxx ; 49N10 ; 35K90

... Lire [+]

Déposez votre fichier ici pour le déplacer vers cet enregistrement.

Research talks;Computer Science

In this talk I will discuss recent joint work with Mike McCourt (SigOpt, San Francisco) that has led to progress on the numerically stable computation of certain quantities of interest when working with positive definite kernels to solve scattered data interpolation (or kriging) problems.
In particular, I will draw upon insights from both numerical analysis and modeling with Gaussian processes which will allow us to connect quantities such as, e.g., (deterministic) error estimates in terms of the power function with the kriging variance. This provides new kernel parametrization criteria as well as new ways to compute known criteria such as MLE. Some numerical examples will illustrate the effectiveness of this approach.
In this talk I will discuss recent joint work with Mike McCourt (SigOpt, San Francisco) that has led to progress on the numerically stable computation of certain quantities of interest when working with positive definite kernels to solve scattered data interpolation (or kriging) problems.
In particular, I will draw upon insights from both numerical analysis and modeling with Gaussian processes which will allow us to connect quantities such as, ...

65D05 ; 68Uxx ; 62H11

... Lire [+]

Déposez votre fichier ici pour le déplacer vers cet enregistrement.

Research talks

The Bézier representation of homogenous polynomials has little and not the usual geometric meaning if we consider the graph of these polynomials over the sphere. However the graph can be seen as a rational surface and has an ordinary rational Bézier representation. As I will show, both Bézier representations are closely related. Further I consider rational spline constructions for spherical surfaces and other closed manifolds with a projective or hyperbolic structure. The Bézier representation of homogenous polynomials has little and not the usual geometric meaning if we consider the graph of these polynomials over the sphere. However the graph can be seen as a rational surface and has an ordinary rational Bézier representation. As I will show, both Bézier representations are closely related. Further I consider rational spline constructions for spherical surfaces and other closed manifolds with a projective ...

65D17 ; 41A15 ; 65D05 ; 65D07

... Lire [+]

Déposez votre fichier ici pour le déplacer vers cet enregistrement.

Special events;30 Years of Wavelets;Analysis and its Applications

42C40 ; 65T60

... Lire [+]

Déposez votre fichier ici pour le déplacer vers cet enregistrement.

Research talks;Analysis and its Applications

The unitary extension principle (UEP) by Ron & Shen yields a convenient way of constructing tight wavelet frames in L2(R). Since its publication in 1997 several generalizations and reformulations have been obtained, and it has been proved that the UEP has important applications within image processing. In the talk we will present a recent extension of the UEP to the setting of generalized shift-invariant systems on R (or more generally, on any locally compact abelian group). For example, this generalization immediately leads to a discrete version of the UEP.
(The results are joint work with Say Song Goh).
The unitary extension principle (UEP) by Ron & Shen yields a convenient way of constructing tight wavelet frames in L2(R). Since its publication in 1997 several generalizations and reformulations have been obtained, and it has been proved that the UEP has important applications within image processing. In the talk we will present a recent extension of the UEP to the setting of generalized shift-invariant systems on R (or more generally, on any ...

42C15 ; 42C40 ; 65T60

... Lire [+]

Déposez votre fichier ici pour le déplacer vers cet enregistrement.

- 336 p.
ISBN 978-0-444-51124-9

Studies in mathematics and its application , 0032

Localisation : Ouvrage RdC (COHE)

analyse numérique # ondelette # approximation non-linéaire # approximation # méthode multigrille # traitement d'image

65T60 ; 42C40 ; 94A08

... Lire [+]

Z