Éditeur(s) : HAL CCSD
Résumé : 28 pages, 6 figures
We study a universal object for the genealogy of a sample in populations with mutations: the critical birth-death process with Poissonian mutations, conditioned on its population size at a fixed time horizon. We show how this process arises as the law of the genealogy of a sample in a large class of critical branching populations with mutations at birth, namely populations converging, in a large population asymptotic, towards the continuum random tree. We extend this model to populations with random foundation times, with (potentially improper) prior distributions g_i: xmapsto x^{-i}, iinZ_+, including the so-called uniform (i=0) and log-uniform (i=1) priors. We first investigate the mutational patterns arising from these models, by studying the site frequency spectrum of a sample with fixed size, i.e. the number of mutations carried by k individuals in the sample. Explicit formulae for the expected frequency spectrum of a sample are provided, in the cases of a fixed foundation time, and of a uniform and log-uniform prior on the foundation time. Second, we establish the convergence in distribution, for large sample sizes, of the (suitably renormalized) tree spanned by the sample genealogy with prior g_i on the time of origin. We finally prove that the limiting genealogies with different priors can all be embedded in the same realization of a given Poisson point measure.
https://hal.archives-ouvertes.fr/hal-01053343

hal-01053343
https://hal.archives-ouvertes.fr/hal-01053343
ARXIV : 1407.7720

Éditeur(s) : HAL CCSD Kluwer
Résumé : This paper presents some considerations about hybrid optimization algorithms useful to optimize real complex system. The given indication could be used by readers to conceive hybrid algorithms. These considerations have been deducted from a concrete application case: the satellites constellations design problem. But each of the advanced techniques proposed in this paper are considered in a more general way to solve other problems. This problem is used to illustrate the techniques along the paper because it is grouping many characteristics (di culties) of contemporary real complex systems: the size and the characteristics of the search space engendered by a combinatorial problem; The irregularity of the criterions; The mathematical and physical heterogeneity of parameters forbids the use of classical algorithms; The evaluation of a solution, which uses a time consuming simulation; A need of accurate values. More details are available in previous papers ([?], [?], [?], [?]). For these reasons, we could learn a lot from this experiment in order to detach hybrid techniques usable for problems having close characteristics. This paper presents the historic leading to the current algorithm, the modeling of the complex system and the sophisticated algorithm proposed to optimize it. Application cases and ways to built signi cant tests of hybrid algorithm are also given.
International Federation for Information Processing

hal-00602279
https://hal.archives-ouvertes.fr/hal-00602279

Éditeur(s) : HAL CCSD
Résumé : International audience
Les processus ponctuels temporel, spatial et spatio-temporel permettent de décrire divers phénomènes consistant en des distributions d'événements : on peut citer les occurrences d'infection en épidémiologie, les épicentres en sismologie, ou les décharges électriques en neurologie. Dans le cadre de la détection de la résurgence de maladies, nous considérons un processus doublement stochastique (Cox) défini par son processus intensité spatio-temporel. Il s'agit d'un modèle hiérarchique spatio-temporel à trois composantes pour la fonction d'intensité : un effet spatial, une tendance temporelle et un effet spatio-temporel. Des études par simulations numériques sont menées afin de vérifier la performance des estimateurs proposés
41èmes Journées de Statistique, SFdS, Bordeaux
Bordeaux, France, France

inria-00386679
https://hal.inria.fr/inria-00386679
https://hal.inria.fr/inria-00386679/document
https://hal.inria.fr/inria-00386679/file/p118.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Evidence of the impact of exposure to low levels of lead on children's health is increasing. Residential floor dust is the assumed origin of lead exposure by young children. In this study, we estimate the contribution of different lead sources to household interior floor dust contamination. We also estimate the within-home variability of interior floor dust lead loadings. A multilevel model was developed based on data collected in a French survey in 2008-2009 (484 housing units, 1834 rooms). Missing data were handled by multiple imputation using chained equations. The intra-home correlation between interior floor Log dust lead loadings was approximately 0.6. Dust lead from the landing of an apartment, mostly originating outside the building, was the major contributor to interior floor dust lead. Secondary contributors included the lead-based paint on exterior railings, track-in of the exterior soil of the children's play area into the dwelling, smoking inside the home, demolition of nearby old buildings and sites of pollution in the vicinity. Interior lead-based paint contaminated interior floor dust only in old and non-renovated dwellings. To reduce interior floor dust lead levels in the general population of dwellings, common areas should be maintained, and track-in from the outside should be limited as much as possible.
ISSN: 0048-9697

hal-01017419
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01017419
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01017419/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01017419/file/Source_Contribution_final.pdf
DOI : 10.1016/j.scitotenv.2013.10.028

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
In this paper, we consider a direct protein transfer process between cells in co-culture. Assuming that cells continually encounter each other, and from some hypotheses on cell-to-cell rules of transfer, we derive discrete and continuous Boltzmann-like integrodifferential equations. The novelty of this model is to take into account multiple transfer rules. This new transfer model is used to fit the experimental data of cell-to-cell protein transfer in breast cancer.
ISSN: 0092-8240

Droits : info:eu-repo/semantics/OpenAccess
hal-01683780
https://hal.univ-antilles.fr/hal-01683780
https://hal.univ-antilles.fr/hal-01683780/document
https://hal.univ-antilles.fr/hal-01683780/file/MNPZF%20Bull%20Math%20Biol%202017.pdf
DOI : 10.1007/s11538-017-0319-9

Éditeur(s) : HAL CCSD
Résumé : International audience
The purpose of our study is to model a geothermal reservoir. When geothermal reservoir are assumed to be composed of pure water, the transfer of mass and energy is classically described by two balance equations: mass balance equation and the energy balance equation. In addition to those equations, fluid velocity ist classically given by the Darcy law while thermodynamic properties, inferred from theoretical or empirical equations of state, are used to close the mathematical system. Once this system is closed, there exist different solutions. The first one is to solve for pressure and temperature with a variable switch to saturation in the two-phase region (e.g. TOUGH2). The second one is to solve for pressure and enthalpy to increase stability of phase transition between single and two-phase states (e.g. Hydrotherm). We adopted the second option and chose te use a splitting method to get rid of the complexity of coupling equations and a finite volume method for the spatial discretization. Selecting object-oriented languages, we developed a multi-language framework, combining Python, Fortran and a C++ implementation of IAPWS (from the freesteam project) including the supercritical equations, in porous media velocity is given by Darcy law and to close the system physical properties are determined by the IAPWS-IF97 thermodynamic formulation. We resolve the equations in pressure and enthalpy instead of pressure and temperature in order to increase stability and to handle easier the passage from a single-phase to a two-phase system. We solve the system by using a splitting method - to get rid of the complexity of coupling equations - and a finite volume method. We offer some freedom to users thanks to the implementation of several methods like explicit or implicit Euler, Runge-Kutta or BDF2 for time solvers or GMRES and BICGSTAB for the linear solver. We can handle several boundary conditions like no-flow - describing a boundary which can not exchange matter with the exterior - or like a mixed-therm condition - a Dirichlet condition to the pressure and a Dirichlet or an outflow condition to the temperature in order to describe a recharge or a discharge zone - ... We're developing a multi-language framework, combining Python, Fortran and the C++ implementation of IAPWS (from the freesteam project). All these languages are object-oriented. We've applied this simulation model to the dogger in Paris, France, to several one-dimensional systems and a two-dimensional one made by Coumou with the CSMP++ platform. The dogger is a reservoir exploited to produce heat by pumping water at 70 and reinjecting it in the reservoir at 40. In the one-dimensional systems we wanted to observe the process of heat transfer from a higher temperature boundary to a smaller one in a high-energy domain. The last simulation shows the natural convection of water in a fault. For every simulation we compared the solutions we found with an other code (TOUGH2 or CSMP++) and they agreed. The next step will be to model the geothermal plant in Guadeloupe, West Indies. It's the only place in France - and in the West Indies so far - producing electricity with the earth power. The temperature can reach up to 1000 and the pressure range is around a few hundreds MPa. In some surface zones we can see two-phase water at atmospheric pressure. In the 1980s Bouillante was a laboratory for France. Since 1995 Bouillante has given 30GWh electricity a year to the Guadeloupeans.
PROCEEDINGS, Thirty-Ninth Workshop on Geothermal Reservoir Engineering
Stanford, United States

Droits : info:eu-repo/semantics/OpenAccess
hal-00944133
https://hal-brgm.archives-ouvertes.fr/hal-00944133
https://hal-brgm.archives-ouvertes.fr/hal-00944133/document
https://hal-brgm.archives-ouvertes.fr/hal-00944133/file/Copol.pdf

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Algorithms issued from the NonLinear Galerkin method have been used in many situations and with different discretizations for the resolution of evolutionary nonlinear equations. The main idea of these methods is to use a splitting of the solution in order to model the equation. According to the splitting of the solution, a splitting of the equation is obtained. The modeling principle is to freeze terms which have a small time variation. In this work we use wavelet discretizations of the 2-D Burgers equations and compare the results with the hierarchical finite elements method. The numerical tests indicate that wavelets give better results than finite elements
ISSN: 0885-7474

hal-00383423
https://hal.archives-ouvertes.fr/hal-00383423
DOI : 10.1007/s10915-004-4806-4

Éditeur(s) : HAL CCSD
Résumé : International audience
In many situations it is important to be able to propose N independent real- izations of a given distribution law. We propose a strategy for making N parallel Monte Carlo Markov Chains (MCMC) interact in order to get an approximation of an indepen- dent N-sample of a given target law. In this method each individual chain proposes can- didates for all other chains. We prove that the set of interacting chains is itself a MCMC method for the product of N target measures. Compared to independent parallel chains this method is more time consuming, but we show through examples that it possesses many advantages. This approach is applied to a biomass evolution model.
International Conference on Applied Statistics for Development in Africa Sada'07
Cotonou, Benin

inria-00506398
https://hal.inria.fr/inria-00506398
https://hal.inria.fr/inria-00506398/document
https://hal.inria.fr/inria-00506398/file/campillo2007b.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
This paper presents some considerations about hybrid optimization algorithms useful to optimize real complex system. The given indication could be used by readers to conceive hybrid algorithms. These considerations have been deducted from a concrete application case: the satellites constellations design problem. But each of the advanced techniques proposed in this paper are considered in a more general way to solve other problems. This problem is used to illustrate the techniques along the paper because it is grouping many characteristics (di culties) of contemporary real complex systems: the size and the characteristics of the search space engendered by a combinatorial problem; The irregularity of the criterions; The mathematical and physical heterogeneity of parameters forbids the use of classical algorithms; The evaluation of a solution, which uses a time consuming simulation; A need of accurate values. More details are available in previous papers ([?], [?], [?], [?]). For these reasons, we could learn a lot from this experiment in order to detach hybrid techniques usable for problems having close characteristics. This paper presents the historic leading to the current algorithm, the modeling of the complex system and the sophisticated algorithm proposed to optimize it. Application cases and ways to built signi cant tests of hybrid algorithm are also given.
HPCSE Proceedings
Toulouse, France

hal-00602264
https://hal.archives-ouvertes.fr/hal-00602264

Éditeur(s) : HAL CCSD EDP Sciences
Résumé : International audience
Modelling environmental problems leads to mathematical systems with missing data. For instance, weather problems have generally missing initial conditions. The paper is concerned with identifying pollution terms arising in the state equation of some dissipative system with incomplete initial condition. To this aim the so-called sentinel method is used. Here, the problem of determining a sentinel is equivalent to a null-controllability problem for which Carleman inequalities are revisited.
ISSN: 1270-900X

hal-00720818
https://hal.univ-antilles.fr/hal-00720818
https://hal.univ-antilles.fr/hal-00720818/document
https://hal.univ-antilles.fr/hal-00720818/file/esaimpr2.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
Calculation of seismic risks in a zone are based on stochastic models describing at best the seismic activity. Our focus is the spatio-temporal evolution of the probability of earthquake occurrences. The main modelling tool is the theory of the point processes. We discuss about the spatio-temporal extension of ETAS (Epidemic Type Aftershock Sequence) with marks and study the properties of the log-likelihood and the maximum likelihood estimators. Seismic data from the Lesser Antilles Arc carried out between 1999 and 2004 are analyzed.
39th Annual Meeting of the Statistical Society of Canada
Wolfville, Canada

hal-00601513
https://hal.archives-ouvertes.fr/hal-00601513

Éditeur(s) : HAL CCSD EDP Sciences
Résumé : We propose and we justify a Monte-Carlo algorithm which solves a spatially homogeneous kinetic equation of Boltzmann type that models the fusion reaction between a deuterium ion and a tritium ion, and giving an α particle and a neutron. The proposed algorithm is validated with the use of explicit solutions of the kinetic model obtained by replacing the fusion cross-section by a Maxwellian cross section.
ISSN: 1270-900X

hal-00689821
https://hal.archives-ouvertes.fr/hal-00689821
https://hal.archives-ouvertes.fr/hal-00689821/document
https://hal.archives-ouvertes.fr/hal-00689821/file/proc_versionHAL.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
Bayesian modelling is fluently employed to assess natural ressources. It is associated with Monte Carlo Markov Chains (MCMC) to get an approximation of the distribution law of interest. Hence in such situations it is important to be able to propose N independent realiza- tions of this distribution law. We propose a strategy for making N parallel Monte Carlo Markov Chains interact in order to get an approximation of an independent N -sample of a given target law. In this method each individual chain proposes candidates for all other chains. We prove that the set of interacting chains is itself a MCMC method for the product of N target measures. Compared to independent parallel chains this method is more time consuming, but we show through example that it possesses many advantages. This approach will be applied to a forest dynamic model.
International Conference on Approximation Methods and Numerical Modelling in Environment and Natural Resources
Granada, Spain

inria-00506591
https://hal.inria.fr/inria-00506591
https://hal.inria.fr/inria-00506591/document
https://hal.inria.fr/inria-00506591/file/campillo2007c.pdf

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
We mainly study a system of two coupled nonlinear Schrödinger equations where one equation includes gain and the other one includes losses. This model constitutes a generalization of the model of pulse propagation in bire-fringent optical fibers. We answered partially to a question of some authors in [8], that in the Manakov case, the solution stays in L 2 (0, T ; H 1), that means that the solution can not blow up in finite time. More precisely, the bound that is provided in this paper does not seem to be optimal but different than those that has been given from a previous study [8]. Thanks to the way we treat the a priori estimate, we obtain a sharp bound in L 2 (0, T ; H 1), which would be difficult to reach from the study of other authors [8]. The result is illustrated by numerical results which have been obtained with a finite element solver well adapted for that purpose.
ISSN: 0022-2526

Droits : http://creativecommons.org/licenses/by/
hal-01270459
https://hal.archives-ouvertes.fr/hal-01270459
https://hal.archives-ouvertes.fr/hal-01270459/document
https://hal.archives-ouvertes.fr/hal-01270459/file/paperver2.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
Dans la cadre de calcul de risques sismiques, nous nous intéressons aux processus ponctuels auto-excitatifs. Une étude comparative de deux modèles est effectuée, il s'agit des modèles ETAS (Epidemic Type Aftershock Sequence) introduit et modifié par Ogata (1988, 1998) et BASS (Branching AfterSchock Sequence) introduit par Turcotte et al. (2007).
19th Caribbean Geological Conference 2011
Le Gosier, Guadeloupe

hal-00601511
https://hal.archives-ouvertes.fr/hal-00601511

Éditeur(s) : HAL CCSD Institute of Electrical and Electronics Engineers
Résumé : International audience
The state-space modeling of partially observed dynamical systems generally requires estimates of unknown parameters. The dynamic state vector together with the static parameter vector can be considered as an augmented state vector. Classical filtering methods, such as the extended Kalman filter (EKF) and the bootstrap particle filter (PF), fail to estimate the augmented state vector. For these classical filters to handle the augmented state vector, a dynamic noise term should be artificially added to the parameter components or to the deterministic component of the dynamical system. However, this approach degrades the estimation performance of the filters. We propose a variant of the PF based on convolution kernel approximation techniques. This approach is tested on a simulated case study.
ISSN: 0018-9251

inria-00459886
https://hal.inria.fr/inria-00459886
DOI : 10.1109/TAES.2009.5259183

Éditeur(s) : HAL CCSD Institute for Scientific Computing and Information
Résumé : International audience
In this paper, we solve a problem describing the mechanical deformations of a porous medium in the presence of a monophasic linear flow or a two phase nonlinear flow with the purpose of modelizing subsidence of hydrocarbon reservoirs. An essential characteristics of this problem is that the mechanical deformation and the flow have different time scales. In petroleum industry, one uses different very efficient simulators for the flow problem and the mechanical deformations, which enables to handle complex models. Therefore it is necessary to be able to combine as efficiently as possible the exploitation of these simulators. We propose two alternative splitting approaches. The first one is the staggered algorithm used by engineers, which amounts to a Gauss-Seidel method in the one phase linear case. The second approach is based upon the preconditioned conjugate gradient method. We use a numerical multi-scale method in both of these algorithms. We compare these two approaches and we show that the preconditioned conjugate gradient algorithm is faster and more robust than the staggered algorithm. Applying the preconditioned conjugate gradient algorithm therefore seems to compensate for the fact that the inf-sup condition for the mixed discretization method is not satisfied when combining the simulators for the mechanical deformations and for the flow computations.
ISSN: 1705-5105

Droits : http://creativecommons.org/licenses/by/
hal-01449039
https://hal.archives-ouvertes.fr/hal-01449039
https://hal.archives-ouvertes.fr/hal-01449039/document
https://hal.archives-ouvertes.fr/hal-01449039/file/DHLE.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
This research aim focused onthe interpretation of the action of pupils for two school professors in mathematics and in physical education. The research is in the field of work concerned with the process of didactic contextalisation (Delcroix, Forissier, Anciaux, 2012). It also mobilizes process of the comparative approach (Mercier, Schubauer-Leoni et Sensevy, 2002). Data processed within the limits of this communication were collected by interview of self-confrontation. The results are used to model the interpretive filters according to three axes: the practical epistemology of the professor through the categories of Shulman (1987), forms of inference employed and his organization. Our study allows us to confront, in this model, the specifics or generics, fruits of disciplinary didactics to the effects of the didactic contextualization. We note that the use of contextualization seems to act as a filter (regardless of the teacher or the discipline concerned) constitutive of a profile kind (in the sense of Clot). Finally, at the end of this research, we discuss the contribution of this type of study for the training of teachers by querying the aspect built of these filters in action-context interaction and by validating the legitimacy of this question: "What is happening in the minds of the students"?Clot, Y. et Faïta, D. (2001). Genre et style en analyse du travail. Concepts et méthodes, Travailler, 6, 7-42Delcroix, A., Forissier, T., & Anciaux, F. (2012). Vers un cadre d’analyse opérationnel des phénomènes de contextualisation didactique. Dans F. Anciaux, T. Forissier et LF. Prudent, Contextualisations didactiques (pp. 141-188). Paris : L’harmattan.Mercier, A., Schubauer-Leoni, ML. & Sensevy, G. (2002). Vers une didactique comparée. Revue française de pédagogie, 141, 5-16.Shulman, L. (1987). « Knowledge and teaching : foundations of the new reform ». Harvard Educational Review, vol. 57, n° 1, p. 1-22.
The Caribbean Academy of Sciences 20th GENERAL MEETING AND BIENNIAL CONFERENCE
Deshaies, Guadeloupe

hal-01618424
https://hal.univ-antilles.fr/hal-01618424

Éditeur(s) : HAL CCSD
Résumé : Mes travaux de recherche portent sur la caractérisation de l’hétérogénéité, précisément des structures spatiales et de la diversité. J’ai développé de nouvelles mesures de la structure spatiale appliquées principalement en économie géographique et des mesures de diversité appliquées principalement à la biodiversité des arbres. Le fil directeur de ces travaux méthodologiques est de construire des mesures correspondant à une réalité physique, facilement compréhensible, pouvant être utilisées ensuite pour comprendre sans ambiguïté les processus économiques ou écologiques concernés.Mon projet de recherche à moyen terme consiste à combiner les deux approches pour caractériser la diversité explicitement dans l’espace et dans le temps, et à étendre mes méthodes à d’autres objets (diversité microbienne par exemple) plus complexes. Au-delà de ces travaux méthodologiques, mon objectif à plus long terme est d’aller vers la modélisation des processus générant les patrons de diversité.
https://hal-agroparistech.archives-ouvertes.fr/tel-01502970

tel-01502970
https://hal-agroparistech.archives-ouvertes.fr/tel-01502970
https://hal-agroparistech.archives-ouvertes.fr/tel-01502970/document
https://hal-agroparistech.archives-ouvertes.fr/tel-01502970/file/HDR%20-%20Marcon%20-%202016.pdf

Éditeur(s) : HAL CCSD Global Science Press
Résumé : International audience
In this paper, the authors present two different time-discretization schemes combined with a finite-volume space discretization for the incompressible Navier-Stokes equations. They show that the collocated space discretization, usually used with a projection method, can also be extended to other time discretizations over previous projection methods, like the splitting methods. The main advantage of this splitting method is that the pressure approximation is truly of second order. In the first and second parts of this article, two different time-discretization schemes are considered with a collocated space discretization and it is explained how the unknown can be correctly coupled. Numerical simulations are presented in the last part. Tests of spatial and time accuracies are made. The numerical results when the Navier-Stokes problem is solved are shown, in the model problem of the driven cavity.
ISSN: 1815-2406

hal-00730191
https://hal.archives-ouvertes.fr/hal-00730191