Publications associées à Joseph Fourier

Sharp sphere packings

In this talk we will speak about recent progress on the sphere packing problem. The packing problem can be formulated for a wide class of metric spaces equipped with a measure. An interesting feature of this optimization problem is that a slight change of ...

World Scientific Publishing2018

Discreteness of interior transmission eigenvalues revisited

Hoài-Minh Nguyên, Quoc Hung Nguyen

This paper is devoted to the discreteness of the transmission eigenvalue problems. It is known that this problem is not self-adjoint and a priori estimates are non-standard and do not hold in general. Two approaches are used. The first one is based on the ...

Springer Verlag2017

The Particle-In-Fourier (PIF) Approach Applied to Gyrokinetic Simulations

Laurent Villard, Stephan Brunner, Emmanuel Lanti, Noé Thomas Elie Ohana, Claudio Gheller, Aaron Lewis Scheinberg

A widespread method for gyrokinetic simulations relies on the discretization of distribution functions with numerical markers. The electromagnetic field is typically represented on a grid by finite differences or finite elements (Particle-In-Cell, PIC). Wh ...

2017

Increasing the Sensitivity to Short-Lived Species in a Modulated Excitation Experiment

Davide Ferri, Oliver Kröcher, Alexander Wokaun

The combination of spectroscopic and diffraction methods to study chemical transformations is fundamental for the understanding of reaction mechanisms. The identification of short-lived species, likely active species, is often hindered by the contribution ...

American Chemical Society2017

Modeling Creeping Flow through a Closed Crack with a Self-Affine Geometry and an Extension to Permeability of Cracked Media, Poromechanics VI

Jean-François Molinari, Guillaume Anciaux, Vladislav Yastrebov

To model a creeping flow through closed cracks in cracked materials we study a normal mechanical contact between two elastic half-spaces with rough surfaces is studied. The roughness is modeled using a filtering technique in Fourier space: the root mean sq ...

2017

An Adaptive Sublinear-Time Block Sparse Fourier Transform

Volkan Cevher, Mikhail Kapralov, Jonathan Mark Scarlett, Amir Zandieh

The problem of approximately computing the

k

dominant Fourier coefficients of a vector

X

quickly, and using few samples in time domain, is known as the Sparse Fourier Transform (sparse FFT) problem. A long line of work on the sparse FFT has resulted in ...

2017

Analytical Time-Domain Solution of Plane Wave Propagation Across a Viscoelastic Rock Joint

Lyesse Laloui, Jian Zhao, Yang Zou

The effects of viscoelastic filled rock joints on wave propagation are of great significance in rock engineering. The solutions in time domain for plane longitudinal ( P-) and transverse ( S-) waves propagation across a viscoelastic rock joint are derived ...

Springer Verlag2017

A vector field method on the distorted Fourier side and decay for wave equations with potentials

Joachim Krieger, Roland Donninger

We study the Cauchy problem for the one-dimensional wave equation

\partial_t^2 u(t,x)-\partial_x^2 u(t,x)+V(x)u(t,x)=0.

The potential

V

is assumed to be smooth with asymptotic behavior

V(x)\sim -\tfrac14 |x|^{-2}\mbox{ as } |x|\to \infty.

...

2016

Sparse regularization methods in ultrafast ultrasound imaging

Jean-Philippe Thiran, Yves Wiaux, Rafael Eduardo Carrillo Rangel, Adrien Georges Jean Besson, Olivier Bernard

Ultrafast ultrasound (US) imaging based on plane wave (PW) insonification is a widely used modality nowadays. Two main types of approaches have been proposed for image reconstruction either based on classical delay-and-sum (DAS) or on Fourier reconstructio ...

Ieee2016

Detecting and Localizing Differences in Functional Time Series Dynamics: A Case Study in Molecular Biophysics

Victor Panaretos, Shahin Tavakoli

Motivated by the problem of inferring the molecular dynamics of DNA in solution, and linking them with its base-pair composition, we consider the problem of comparing the dynamics of functional time series (FTS), and of localizing any inferred differences ...

American Statistical Association2016

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Sharp sphere packings

Discreteness of interior transmission eigenvalues revisited

The Particle-In-Fourier (PIF) Approach Applied to Gyrokinetic Simulations

Increasing the Sensitivity to Short-Lived Species in a Modulated Excitation Experiment

Modeling Creeping Flow through a Closed Crack with a Self-Affine Geometry and an Extension to Permeability of Cracked Media, Poromechanics VI

An Adaptive Sublinear-Time Block Sparse Fourier Transform

Analytical Time-Domain Solution of Plane Wave Propagation Across a Viscoelastic Rock Joint

A vector field method on the distorted Fourier side and decay for wave equations with potentials

Sparse regularization methods in ultrafast ultrasound imaging

Detecting and Localizing Differences in Functional Time Series Dynamics: A Case Study in Molecular Biophysics

Sharp sphere packings

The Particle-In-Fourier (PIF) Approach Applied to Gyrokinetic Simulations

Increasing the Sensitivity to Short-Lived Species in a Modulated Excitation Experiment

Modeling Creeping Flow through a Closed Crack with a Self-Affine Geometry and an Extension to Permeability of Cracked Media, Poromechanics VI

Analytical Time-Domain Solution of Plane Wave Propagation Across a Viscoelastic Rock Joint

An Adaptive Sublinear-Time Block Sparse Fourier Transform

A vector field method on the distorted Fourier side and decay for wave equations with potentials

Sparse regularization methods in ultrafast ultrasound imaging

Detecting and Localizing Differences in Functional Time Series Dynamics: A Case Study in Molecular Biophysics

Discreteness of interior transmission eigenvalues revisited