Jérôme Fehrenbach

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While walking through a crowd, a pedestrian experiences a large number of interactions with his neighbors. The nature of these interactions is varied, and it has been observed that macroscopic phenomena emerge from the combination of these local interactions. Crowd models have hitherto considered collision avoidance as the unique type of interactions(More)
We consider the generalized Graetz problem associated with stationary convection-diffusion inside a domain having any regular three dimensional translationally invariant section and finite or semi-infinite extent. Our framework encompasses any previous “extended” and “conjugated” Graetz generalizations and provides theoretical bases for computing the(More)
A framework and an algorithm are presented in order to remove stationary noise from images. This algorithm is called variational stationary noise remover. It can be interpreted both as a restoration method in a Bayesian framework and as a cartoon+texture decomposition method. In numerous denoising applications, the white noise assumption fails. For example,(More)
We introduce a new discretization scheme for Anisotropic Diffusion, AD-LBR, on two and three dimensional Cartesian grids. The main features of this scheme is that it is non-negative and has sparse stencils, of cardinality bounded by 6 in 2D, by 12 in 3D, despite allowing diffusion tensors of arbitrary anisotropy. The radius of these stencils is not a-priori(More)
Multicellular tumor spheroids are models of increasing interest for cancer and cell biology studies. They allow considering cellular interactions in exploring cell cycle and cell division mechanisms. However, 3D imaging of cell division in living spheroids is technically challenging and has never been reported. Here, we report a major breakthrough based on(More)
RÉSUMÉ. Certains tissus biologiques comme la prostate peuvent être considérés comme un matériau élastique linéaire et isotrope, au moins pour de petites déformations. Un problème intéressant du point de vue médical est de détecter des hétérogénéités où le module d’Young prend une valeur différente du reste. On se donne ici un matériau homogène sauf dans(More)
In human crowds as well as in many animal societies, local interactions among individuals often give rise to self-organized collective organizations that offer functional benefits to the group. For instance, flows of pedestrians moving in opposite directions spontaneously segregate into lanes of uniform walking directions. This phenomenon is often referred(More)
The in situ oxygen partial pressure in normal and tumor tissues is in the range of a few percent. Therefore, when studying cell growth in 3D culture systems, it is essential to consider how the physiological oxygen concentration, rather than the one in the ambient air, influences the proliferation parameters. Here, we investigated the effect of reducing(More)
We propose an algorithm to estimate the motion between two images. This algorithm is based on the nonlinear brightness constancy assumption. The number of unknowns is reduced by considering displacement fields that are piecewise linear with respect to each space variable, and the Jacobian matrix of the cost function to be minimized is assembled rapidly(More)