Convolution mixture of FBF and modulated FBF and application to HRTEM images

International audienceIn this paper, we propose a mixture involving a fractional Brownian field and a modulated version of such a field for modeling High Resolution Transmission Electron Microscopy (HRTEM) textures. The mixture under consideration is defined from the convolution operator applied on spatial variables of the two fields under consideration. We present estimation methods for the parameters of the model (2 Hurst parameters and 2 spectral poles) based on Wavelet Packet (WP) spectrum. The relevance of our method is highlighted by its application to the analysis of HRTEM images with active phases of a catalyst.Dans cet article, nous proposons de modéliser certaines textures apparaissant dans les images à Haute Résolution de Microscopie Electronique en Transmission (HRMET) à l'aide d'un mélange composé d'un champ Brownien fractionnaire avec une version modulée d'un tel champ. Le mélange en question est basé sur un opérateur de convolution s'appliquant sur les variables spatiales des deux champs considérés. Nous présentons deux méthodes d'estimation des paramètres de Hurst du modèle en utilisant une approche par ondelettes. Nous présentons également une méthode pour localiser les pôles du modèle. Nous montrons la pertinence de ce modèle en l'appliquant à l'analyse des images HRMET contenant des phases actives d'un catalyseur. Abstract-In this paper, we propose a mixture involving a fractional Brownian field and a modulated version of such a field for modeling High Resolution Transmission Electron Microscopy (HRTEM) textures. The mixture under consideration is defined from the convolution operator applied on spatial variables of the two fields under consideration. We present estimation methods for the parameters of the model (2 Hurst parameters and 2 spectral poles) based on Wavelet Packet (WP) spectrum. The relevance of our method is highlighted by its application to the analysis of HRTEM images with active phases of a catalyst

Quantitative analysis of backchannels uttered by an interviewer during neuropsychological tests

International audienceThis paper examines in detail the backchannels uttered by a French professional interviewer during a neuropsychological test of verbal memories. These backchannels are short utterances such as oui, d'accord, uhm, etc. They are mainly produced here to encourage subjects to retrieve a set of words after their controlled encoding. We show that the choice of lexical items, their production rates and their associated prosodic contours are influenced by the subject performance and conditioned by the protocol

ARFBF MODEL FOR NON STATIONARY RANDOM FIELDS AND APPLICATION IN HRTEM IMAGES

International audienceThis paper presents a new model called Autoregressive Fractional Brownian Field (ARFBF) for analyzing textures which contain stationary and non-stationary components. The paper also proposes two estimation methods for the parameter of an isotropic fractional Brownian field based on Wavelet Packet (WP) spectrum: the Log-Regression on Diagonal WP spectrum (Log-RDWP) and the Log-Regression on Polar representation of WP spectrum (Log-RPWP). The Log-RPWP method provides a better estimation performance for small size images. We show the interest of ARFBF model and Log-RPWP for characterizing High-Resolution Transmission Electron Microscopy (HRTEM) images

Towards a better comprehension of reactive transport coupling experimental and numerical approaches

In this work we focus on further understanding reactive transport in carbonate rocks, in particular limestones characterized by a bimodal pore size distribution. To this end, we performed injection experiments with CO2-saturated water on a sample of Euville limestone and monitored the experiments with a medical CT scanner. Microscanner imaging was performed before and after alteration. Experiments showed that permeability increased by nearly two decades due to the alteration process. This increase could be attributed to the formation of a preferential dissolution path visualized on the CT images. Microscanner images show that preferential dissolution areas are characterized by the presence of numerous enlarged macropores. The preferential dissolution path created therefore retains a porous structure and does not correspond to a wormhole-type channel. To provide further knowledge of the small-scale physics of reactive transport, we performed Lattice-Boltzmann simulations of flow in a numerically generated model 2D porous medium having geometrical and topological features designed to approach Euville limestone. We showed that the fluid velocity increased in nearly percolating paths of macropores. Considering the experiments, this means that the CO2-saturated water starts to enter high-velocity zones earlier than low-velocity zones, inducing an earlier onset of the alteration process and a more pronounced local dissolution. However, numerical results showed that the alteration of non-connected macropores leads to an increase of permeability much smaller than the experimentally observed one. To explain this fact we used effective medium modelling that permits predicting the variation in permeability as a function of the fraction of macropores and consequently as a function of alteration. It proved that as long as there is no alteration-induced percolating path consisting of macropores, the increase in permeability is relatively low as shown by the Lattice-Boltzmann simulations. An increase in permeability of several orders of magnitude is only observed when the macroporosity is close to the percolation threshold. This fact is in accordance with the experimentally observed results

Peut-on prévoir la neuropathologie d'une aphasie progressive primaire ?

National audienc

CONNAISSANCES SEMANTIQUES ET MALADIE D'ALZHEIMER (APPORT DE LA NEUROPSYCHOLOGIE COGNITIVE (DOCTORAT : NEUROPSYCHOLOGIE))

LYON1-BU Santé (693882101) / SudocPARIS-BIUM (751062103) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

INTERET COMPARE DE TESTS COGNITIFS BREFS ET DU BILAN NEUROPSYCHOLOGIQUE POUR LE DIAGNOSTIC DE DEMENCE (ETUDE RETROSPECTIVE DANS LE CADRE DE LA CONSULTATION MEMOIRE DU CHU DE GRENOBLE)

GRENOBLE1-BU Médecine pharm. (385162101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

LA MALADIE D'ALZHEIMER (THERAPEUTIQUES ET ROLE DU PHARMACIEN D'OFFICINE)

GRENOBLE1-BU Médecine pharm. (385162101) / SudocSudocFranceF

Organisation des connaissances sémantiques. Des modèles classiques aux modèles non abstractifs

International audienc

Evaluation d'un cas d'aphasie progressive primaire fluente sans deficit sémantique global.

International audienc