Papers by Emmanuel Frénod
State-of-the-art techniques in generative artificial intelligence are employed for the first time... more State-of-the-art techniques in generative artificial intelligence are employed for the first time to construct a surrogate model for plasma turbulence that enables long time transport simulations. The proposed GAIT (Generative Artificial Intelligence Turbulence) model is based on the coupling of a convolutional variational auto-encoder, that encodes precomputed turbulence data into a reduce latent space, and a deep neural network and decoder that generate new turbulence states 400 times faster than the direct numerical integration. The model is applied to the Hasegawa-Wakatani (HW) plasma turbulence model, that is closely related to the quasigeostrophic model used in geophysical fluid dynamics. Very good agreement is found between the GAIT and the HW models in the spatio-temporal Fourier and Proper Orthogonal Decomposition spectra as well as in the flow topology characterized by the Okubo-Weiss decomposition. Agreement is also found in the probability distribution function of particle displacements and the effective turbulent diffusivity.
ESAIM, Dec 1, 2016
In this paper, we propose a mathematical model to describe the functioning of a bioreactor landfi... more In this paper, we propose a mathematical model to describe the functioning of a bioreactor landfill, that is a waste management facility in which biodegradable waste is used to generate methane. The simulation of a bioreactor landfill is a very complex multiphysics problem in which bacteria catalyze a chemical reaction that starting from organic carbon leads to the production of methane, carbon dioxide and water. The resulting model features a heat equation coupled with a nonlinear reaction equation describing the chemical phenomena under analysis and several advection and advection-diffusion equations modeling multiphase flows inside a porous environment representing the biodegradable waste. A framework for the approximation of the model is implemented using Feel++, a C++ open-source library to solve Partial Differential Equations. Some heuristic considerations on the quantitative values of the parameters in the model are discussed and preliminary numerical simulations are presented. * This work has been supported by the LMBA Université de Bretagne-Sud, the project PEPS Amies VirtualBioReactor and the private funding of Seed and Entreprise Charier. The project is hosted on the facilities at CEMOSIS whose support is kindly acknowledged. M. Giacomini is member of the DeFI team at Inria SaclayÎle-de-France.
Modeling coastal ocean over a period of several weeks
International audienc
Two-Scale Numerical Method for the Simulation of Particle Beams in a Focussing Channel
Two-Scale Approach to Oscillatory Singularly Perturbed Transport Equations, 2017
A beam is a set of charged particles, which all have the same charge, all move in the same direct... more A beam is a set of charged particles, which all have the same charge, all move in the same direction, the so-called the beam axis, and are confined around this axis.
From the experimental data of the asymetric cleavage test at the bonded joint we studied the crac... more From the experimental data of the asymetric cleavage test at the bonded joint we studied the crack length propagation as a function of the fracture energy thanks an artificial neural networks. We used the Nonlinear Autoregressive Exogenous (NARX) neural network. The model predicts the crack length with a good agreement with the experimental findings. However, training of the stabilization crack on too long time can cause over-training.
New Results - Simulations of highly oscillatory Vlasov-Poisson system
Contrôle optimal d'un modèle financier continu
Aujourd'hui lorsqu'une societe ou bien une collectivite publique se lance dans un projet ... more Aujourd'hui lorsqu'une societe ou bien une collectivite publique se lance dans un projet qui implique un credit, il est necessaire de trouver le meilleur plan d'emprunt. Ce dernier est defini comme etant la strategie qui permet d'atteindre les objectifs du projet tout en minimisant le cout de l'emprunt. Cette strategie doit tenir compte du delai du projet, du taux d'interet de l'emprunt, des recettes et des depenses courantes. Une fois cette strategie est etablie, et tout au long du deroulement du projet, il est indispensable de controler la facon dont le plan de l'emprunt est implemente. Le but est de contrebalancer l'ecart entre l'environnement reel du projet et l'environnement qui avait ete projete lors de l'elaboration de la strategie. Dans cet expose nous adaptons tout d'abord le modele financier continu en temps, developpe par [Frenod & Chakkour] afin de l'utiliser dans le cadre de la theorie de controle. Ce modele, qui n...
New Results - Mathematical analysis of kinetic models
Studies in Computational Intelligence, Nov 26, 2019
Graphs increasingly stand out as an essential data structure in the field of data sciences. To st... more Graphs increasingly stand out as an essential data structure in the field of data sciences. To study graphs, or sub-graphs, that characterize a set of observations, it is necessary to describe them formally, in order to characterize equivalence relations that make sense in the scope of the considered application domain. Hence we seek to define a canonical graph notation, so that two isomorphic (sub) graphs have the same canonical form. Such notation could subsequently be used to index and retrieve graphs or to embed them efficiently in some metric space. Sequential optimized algorithms solving this problem exist, but do not deal with labeled edges, a situation that occurs in important application domains such as chemistry. We present in this article a new algorithm based on graph rewriting that provides a general and complete solution to the graph canonization problem. Although not reported here, the formal proof of the validity of our algorithm has been established. This claim is clearly supported empirically by our experimentation on synthetic combinatorics as well as natural graphs. Furthermore, our algorithm supports distributed implementations, leading to efficient computing perspectives.
Applications
Lecture Notes in Mathematics, 2017
Transactions on Engineering Technologies, 2018
In this paper we study the two-scale behavior of the electromagnetic field in 3D in a composite m... more In this paper we study the two-scale behavior of the electromagnetic field in 3D in a composite material. It is the continuation of the paper (Canot and Frenod Method of homogenization for the study of the propagation of electromagnetic waves in a composite 2017) [7] in which we obtain existence and uniqueness results for the problem, we performed an estimate that allows us to approach homogenization. Techniques of asymptotic expansion and two-scale convergence are used to obtain the homogenized problem. We justify the two-scale expansion numerically in the second part of the paper.
Production monitoring in real-time is a very important problem in smart manufacturing. It helps e... more Production monitoring in real-time is a very important problem in smart manufacturing. It helps enterprises to timely detect abnormalities in the production process and then guarantee the product quality and reduce waste. In this paper, we develop a novel method to monitor the real-time production based on the Convolution Neural Network and the Support Vector Data Description algorithm. The numerical result shows that our proposed method leads to high efficient on the testing data.
In this paper, we propose a mathematical model to describe the functioning of a bioreactor landfi... more In this paper, we propose a mathematical model to describe the functioning of a bioreactor landfill, that is a waste management facility in which biodegradable waste is used to generate methane. The simulation of a bioreactor landfill is a very complex multiphysics problem in which bacteria catalyze a chemical reaction that starting from organic carbon leads to the production of methane, carbon dioxide and water. The resulting model features a heat equation coupled with a nonlinear reaction equation describing the chemical phenomena under analysis and several advection and advection-diffusion equations modeling multiphase flows inside a porous environment representing the biodegradable waste. A framework for the approximation of the model is implemented using Feel++, a C++ open-source library to solve Partial Differential Equations. Some heuristic considerations on the quantitative values of the parameters in the model are discussed and preliminary numerical simulations are presented.
Since the construction of the Arzal dam between 1965 and 1970, the Vilaine estuary is characteriz... more Since the construction of the Arzal dam between 1965 and 1970, the Vilaine estuary is characterized by a strong silting up. Hydrodynamic climates could be identified as responsible for erosion or deposition at different spatio-temporal scales from bathymetrical, hydrological and altimetric (NKE-Altus) data. Each thickness of eroded or deposited sediment could be associated to a typical hydrodynamic climate. Furthermore, it was possible to show the effect of a ridge-runnel bedforms or a smooth surface on the dynamic of the intertidal mudflat. Received 26 April 2009, accepted 1 September 2009, available online 20 December 2010. Translated version not certified, published under the responsibility of the article authors. 6.18 : Revue Paralia – Vol. 3 (2010)
The aim of this Special Session is to take stoke of Numerical Methods for solving Partial Di↵eren... more The aim of this Special Session is to take stoke of Numerical Methods for solving Partial Di↵erential Equations that manage Multi-Scale Phenomena, Oscillations and Heterogeneities by incorporating concepts coming from Homogenization Theory and Two-Scale Convergence. At the present time, there are several research program exploiting this kind of ideas. They concern Hyperbolic, Elliptic and Parabolic PDE. The application fields are Environmental Sciences, Fluid Dynamics, Elasticity, Tokamak Physic, ... One of the goal of this special session is to gather people working in di↵erent teams of di↵erent countries and having in mind di↵erent applications in order to exhibit and synthesize what is common between the di↵erent fields.
Graph canonization (that solves also the graph isomorphism question) is an old problem that still... more Graph canonization (that solves also the graph isomorphism question) is an old problem that still attracts a lot of attention today, mainly because of the ubiquitous aspect of graph-based structures in computer science applications. This article present the proofs of correctness for the SCOTT algorithm, a graph canonization algorithm designed to provide a Canonical form for general graphs, namely graphs for which vertices and edges are coloured (labelled). These proofs ensure that the three canonical forms provided by SCOTT are valid, namely a canonical adjacency matrix, a canonical rooted tree (or DAG) and a canonical string. In addition, some crude lower and upper complexity bounds are presented and discussed. Finally some empirical evaluation is provided on a difficult synthetic benchmark with some comparison with the state of the art algorithms.
Open Journal of Statistics, 2017
Aspects of human behavior in cyber security allow more natural security to the user. This researc... more Aspects of human behavior in cyber security allow more natural security to the user. This research focuses the appearance of anticipating cyber threats and their abstraction hierarchy levels on the mental picture levels of human. The study concerns the modeling of the behaviors of mental states of an individual under cyber attacks. The mental state of agents being not observable, we propose a non-stationary hidden Markov chain approach to model the agent mental behaviors. A renewal process based on a nonparametric estimation is also considered to investigate the spending time in a given mental state. In these approaches, the effects of the complexity of the cyber attacks are taken into account in the models.
ESAIM: Proceedings and Surveys, 2016
Approximation �rayon de Larmor fini� pour l'�quation de Vlasov
C R Acad Sci Ser I Math, 2000
Revue Paralia, 2010
est soumis à un fort envasement. A partir de données bathymétriques, hydrologiques et altimétriqu... more est soumis à un fort envasement. A partir de données bathymétriques, hydrologiques et altimétriques (Altus), il est possible d'identifier des climats hydrodynamiques à différentes échelles spatiales et temporelles et de mieux quantifier les phases d'érosion ou de dépôt associées. De plus, il a été possible de montrer l'impact d'un modelé en seillons/banquettes ou d'un modelé plan sur la dynamique de la vasière.
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Papers by Emmanuel Frénod