Tesi sul tema "Paludisme – Transmission – Modèles mathématiques"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-50 saggi (tesi di laurea o di dottorato) per l'attività di ricerca sul tema "Paludisme – Transmission – Modèles mathématiques".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi le tesi di molte aree scientifiche e compila una bibliografia corretta.
Yacheur, Souâd. "Modélisation et étude mathématique de la propagation d’une maladie vectorielle (paludisme) au sein d’une population". Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0311.
The main purpose of this thesis is to study a class of mathematical models describing some problems related to the infection by the Plasmodium falciparum parasite which causes malaria and whose vector is the mosquito.The work is divided into three main parts, the first part is related to the analysis of the spread of malaria in an isolated population. The global stability of the disease-free equilibrium is studied according to the different epidemiological parameters when the number of basic reproduction is lower than one. When this number is higher than one, the existence of a unique endemic equilibrium is proved. Inspired by the geometric approach introduced by Li and Muldowney, we provided a sufficient condition for this endemic equilibrium to be globally asymptotically stable.A state estimator was constructed to estimate the size of human populations based on the measurement of the number of newly infected humans per unit time. We also proposed two control strategies to eradicate the disease.Finally, to better understand the dynamics of the spread of the disease and to identify the most influential parameters, we have studied the local sensitivity of the number of basic reproduction with respect to each parameter.The second part is about the study of a model that describes the interaction and the spread of the disease within a human population that is divided into two subpopulations, local and non-local. The first subpopulation follows a linear growth while the non-local population follows a logistic growth among the first. We choose to study the impact of the migration of people from an endemic country to another country declared free of the disease or towards the eradication of the disease.Our analysis yielded conditions of the persistence of the disease, we studied the possibility of controlling the disease in a first step through the control of the carrying capacity, then we developed a method based on a matrix called matrix of vectorial transmission which was used to determine the link between the two subpopulations and the population of mosquitoes, according to the values of this matrix entries in order to ensure the control of the disease spread. In addition, a local and global sensitivity study of the level of local and non-local infection was performed to determine the most influential model input parameters.The last part is devoted to the study of the global dynamics of models with multiple subpopulations that are assumed to be weakly interconnected. Our work highlights a process that allows us to perform a complete analysis of many dynamical systems modeling the spread of a disease that involves different populations. The objective is to be able to determine the global stability of the disease-free equilibrium when the basic reproduction number is less than one as well as the global stability of the different types (interior or frontier) of endemic equilibria as a function of the different local basic reproduction numbers and the nature of the interconnections between the network components
Sallah, Kankoe. "Diffusion spatio-temporelle des épidémies : approche comparée des modélisations mathématiques et biostatistiques, cibles d'intervention et mobilité humaine". Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0607.
In the first part of this thesis, we have developed a malaria transmission metamodel based on the susceptible-infected-resistant compartmental modeling framework (SIR) and taking into consideration human mobility flows between different villages in the Center of Senegal. Geographically targeted intervention strategies had been shown to be effective in reducing the incidence of malaria both within and outside of intervention areas. However, combined interventions targeting both vector and host, coordinated on a large scale are needed in regions and countries aiming to achieve malaria elimination in the short/medium term.In the second part we have evaluated different methods of estimating human mobility in the absence of real data. These methods included spatio-temporal traceability of mobile phones, mathematical models of gravity and radiation. The transport of the pathogen through the geographical space via the mobility of an infected subject is a major determinant of the spread of an epidemic. We introduced the impedance model that minimized the mean square error on mobility estimates, especially in contexts where population sets are characterized by their heterogeneous sizes.Finally, we have expanded the framework of assumptions underlying the calibration of the gravity models of human mobility. The hypothesis of a zero inflated distribution provided a better fit and a better predictability, compared to the classical approach not assuming an excess of zeros: Poisson, Quasipoisson
Tewa, Jean Jules. "Analyse globale des modèles épidémiologiques multi-compartimentaux : application à des modèles intra-hôtes de paludisme et de V.I.H". Metz, 2007. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2007/Tewa.Jean_Jules.SMZ0710.pdf.
In this thesis, we analyse intrahost models of malaria and H. I. V. These models are of relatively recent appearance and describe the dynamics of the various stages of the parasites, like their interaction with the host cells, in particular the red blood cells and the immunity effectors. During this decade, there was a considerable work on the mathematical modeling of plasmodium falciparum infection ; a review has been done by Molineaux and Dietz. Our work forms part of this effort of comprehension of the models of Anderson, May and Gupta. The study of these models aims three principal goals : to explain the observations by biologically convincing assumptions, to predict the impact of the interventions (for example the use of the anti-paludic drugs and impregnated mosquito nets) and to consider the parameters hidden (one of these parameters being size of the sequestered population of red blood cells). We analyze the stages progression and the differential infectivity models ; then we leave the original model of Anderson, May and Gupta to propose and analyze a general model having the double advantage of describing the dynamics of evolution of the red blood cells, as well as the stages of morphological evolution of the parasites inside the parasitized red blood cells ; to finish we analyze a model whose innovation compared to the precedent is the bond between the compartment of susceptibles and that of the infectious one. We establish in all the studied cases here the global asymptotic stability of the disease free equilibrium (DFE) when the basic reproduction ratio R0 1. What means that the disease naturally dies out. We also obtain for each model studied here, a condition for global asymptotic stability of the endemic equilibrium when R0 > 1. In certain cases, the principle of exclusive competition is also used to slice
Tsanou, Berge. "Etude de quelques modèles épidémiologiques de métapopulations : application au paludisme et à la tuberculose". Electronic Thesis or Diss., Université de Lorraine, 2012. http://www.theses.fr/2012LORR0055.
The objective of this thesis is first the modeling, the mathematical analysis and numerical simulations of the metapopulation models of infectious diseases based on some modern approaches of the mobility patterns of humans. Secondly to examine the influence of the mobility (movement) of people on the spread of some human infectious diseases. Finally to deal with the difficult question of the existence and stability of endemic equilibria of metapopulation models. For certain diseases such as Malaria, Tuberculosis or some Sexually Transmitted Diseases that do not confer any immunity, we give some metapopulation models that extend to multiple patches the well know epidemiological models in one patch. Our models are based on the mobility patterns of humans wich can take different forms leading to numerous approaches of modeling metapopulations : the Euler approach of the movement of particles (here humans) as in Fluid Mechanics, is used in the first part. The Lagrange approach of the movement of particles (here humans) as in Fluid Mechanics, is used in the second part. The last and more recent approach based on Statistical Mechanics, wich takes into account the degree distribution of the network of the metapopulation is used in the third and last part of this work. For each approach, we build a metapopulation model for a chosen disease, and gve its mathematical analysis. The theoretical framework we use to analyze ou models is that of triangular, monotone or anti-monotone non-linear dynamical systems. We also use some Lyapunov-Lasalle techniques. In the fisrt two parts of our work, we prove that the steady solutions (called equilibria) of the given systems are globally asymptotically stable when the basic reproduction number R0 is less than or equal to the unity (for the disease free equilibria), and when R0 is greater than one (for the endemic equilibria). In the last part, we build a model to describe the spreading of tuberculosis hinging on the two most used forces of infection in mathematical modeling of epidemics : the frequency-dependant transmission and the density-dependant transmission. For each type of trasmission model, we give the explicit formula for the basic reproduction number. We prove for the frequency-dependant transmission model, that the disease free equilibrium is globally asymptotically stable when R0 is less than one. And for the density-dependant transmission model, we prove the existence of an endemic equilibrium when R0 is greater than one. Numerical simulations are performed at the end of each part to examine the influence of human's mobility on the basic reproduction number, as well as on the behavior of the solutions and consequently on the spreading patterns of the diseases under study
Baudet-Fabre, Sylvie. "Modélisation bidimensionnelle de la transmission d'une onde électromagnétique à travers un plasma". Palaiseau, École polytechnique, 1991. http://www.theses.fr/1991EPXX0002.
Laurens, Jérôme. "Modélisation de la transmission acoustique". Lyon 1, 1993. http://www.theses.fr/1993LYO10045.
Tsanou, Berge. "Etude de quelques modèles épidémiologiques de métapopulations : application au paludisme et à la tuberculose". Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0055/document.
The objective of this thesis is first the modeling, the mathematical analysis and numerical simulations of the metapopulation models of infectious diseases based on some modern approaches of the mobility patterns of humans. Secondly to examine the influence of the mobility (movement) of people on the spread of some human infectious diseases. Finally to deal with the difficult question of the existence and stability of endemic equilibria of metapopulation models. For certain diseases such as Malaria, Tuberculosis or some Sexually Transmitted Diseases that do not confer any immunity, we give some metapopulation models that extend to multiple patches the well know epidemiological models in one patch. Our models are based on the mobility patterns of humans wich can take different forms leading to numerous approaches of modeling metapopulations : the Euler approach of the movement of particles (here humans) as in Fluid Mechanics, is used in the first part. The Lagrange approach of the movement of particles (here humans) as in Fluid Mechanics, is used in the second part. The last and more recent approach based on Statistical Mechanics, wich takes into account the degree distribution of the network of the metapopulation is used in the third and last part of this work. For each approach, we build a metapopulation model for a chosen disease, and gve its mathematical analysis. The theoretical framework we use to analyze ou models is that of triangular, monotone or anti-monotone non-linear dynamical systems. We also use some Lyapunov-Lasalle techniques. In the fisrt two parts of our work, we prove that the steady solutions (called equilibria) of the given systems are globally asymptotically stable when the basic reproduction number R0 is less than or equal to the unity (for the disease free equilibria), and when R0 is greater than one (for the endemic equilibria). In the last part, we build a model to describe the spreading of tuberculosis hinging on the two most used forces of infection in mathematical modeling of epidemics : the frequency-dependant transmission and the density-dependant transmission. For each type of trasmission model, we give the explicit formula for the basic reproduction number. We prove for the frequency-dependant transmission model, that the disease free equilibrium is globally asymptotically stable when R0 is less than one. And for the density-dependant transmission model, we prove the existence of an endemic equilibrium when R0 is greater than one. Numerical simulations are performed at the end of each part to examine the influence of human's mobility on the basic reproduction number, as well as on the behavior of the solutions and consequently on the spreading patterns of the diseases under study
Landon, Damien. "Perturbation et excitabilité dans des modèles stochastiques de transmission de l'influx nerveux". Phd thesis, Université d'Orléans, 2012. http://tel.archives-ouvertes.fr/tel-00752088.
Tsanou, Berge. "Etude de quelques modèles épidémiologiques de métapopulation: application à la tuberculose et au paludisme". Phd thesis, Université de Lorraine, 2012. http://tel.archives-ouvertes.fr/tel-00844180.
Diaby, M'Paly. "Caracterisation des materiaux viscoelastiques par analyse modale experimentale". Le Mans, 1998. http://www.theses.fr/1998LEMA1010.
Pham, Tuan Minh. "Modélisation et analyse de la distribution de contenus dans un réseau DTN". Paris 6, 2011. http://www.theses.fr/2011PA066554.
Faucher, Sébastien. "Modélisation quasi-analytique des composants passifs hybrides planar par la méthode des lignes de transmission". Montpellier 2, 2003. http://www.theses.fr/2003MON20153.
Rochet, Marie-Joëlle. "Apports des modèles mathématiques en épidémiologie : points de vue sur la filariose de Bancroft". Lyon 1, 1991. http://www.theses.fr/1991LYO10237.
Noubissi, Justin-Hervé. "Modélisation et simulation spatio-temporelles de systèmes dynamiques complexes avec application en épidémiologie : cas du paludisme". Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS281.
Stomping out malaria remains a big challenge for computer scientists, mathematicians, epidemiologists, entomologists, medicine doctors and many others. Their approaches range from the cure of the patients to the total disappearance of the disease. However, the collaboration, not always efficient between all these scientists leads to the setting up of incomplete prototypes or to an under-exploitation of the results obtained. Environmental and climatic factors are part of these elements that are generally omitted by computer scientists and mathematicians in their modeling of the dynamic of the disease transmission. The tropical countries most affected by the disease are also mostly underdeveloped or developing countries and therefore, statistical data are often lacking or difficult to access. The populations are constantly in motion over ecosystems with different environmental and climatic conditions from one region to another. In this thesis, we propose a model that integrates migratory, spatial and temporal elements, while ensuring the stability conditions in the mathematical sense. We present the disease, study existing approaches and present their limitations in our context, and then propose three types of models that we compare: a meta-population model without consideration of climatic factors, a meta-populations with consideration of climatic factors during the human-mosquito contact and a meta-populations model with consideration of climatic factors throughout the evolutionary process of the mosquito ; This last appears to be the most realistic
Lajeunesse, Francis. "Modélisation de l'intégration des entrées synaptiques excitatrices chez les cellules thalamocorticales". Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28114/28114.pdf.
Thalamocortical (TC) cells from the ventroposterolateral (VPL) nucleus of the thalamus relay the somatosensory inputs (excitatory lemniscal synapses at proximal dendrites) to the corresponding cortical area, but also receive feedback excitatory inputs from the cortex (corticothalamic synapses at distal dendrites). The goal of this study was to compare the synaptic integration of inputs coming to proximal vs. distal dendrites. A multicompartmental model was drawn from fully reconstructed cells of the VPL nucleus. Dendrites were spatially discretized in multiple segments associated to interconnected RC circuits. We were able to characterize the impact of neuronal size and dendritic diameter on the amplitude and on the time course of the somatic response. We also compared the synaptic integration for different distributions of proximal or distal inputs under different conditions of membrane potential and active properties. In all cases, the summation of proximal inputs was independent of their distribution, while the response induced by distal inputs saturated when those inputs were located at the same branches. The results obtained in this study suggest a physiological explanation of the synaptic pattern at TC cells.
Silhol, Romain. "Estimation et validation de modèles individus-centrés de propagation épidémique : la varicelle en Corse". Paris 6, 2011. http://www.theses.fr/2011PA066180.
Toussile, Wilson. "Sélection de variable : structure génétique d'une population et transmission de Plasmodium à travers le moustique". Phd thesis, Université Paris Sud - Paris XI, 2010. http://tel.archives-ouvertes.fr/tel-00553674.
Arnault, Axel. "Simulation et optimisation de l'intégration de matériaux à changement de phase dans une zone thermique". Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/28549/28549.pdf.
Naulin, Jean-Marc. "Simulations numériques et analyse mathématique de modèles de viroses dans des populations structurées". Bordeaux 1, 2001. http://www.theses.fr/2001BOR12454.
Sun, Hao. "Étude mathématique de quelques systèmes biologiques". Compiègne, 1989. http://www.theses.fr/1989COMPD205.
This thesis is devoted essentially to the mathematical and numerical study of several biological systems. These systems of acetylcholinesterase are derived to describe the phenomena of synaptic transmission under certain hypotheses. Oscillations obtained by numerical simulation have been confirmed by the experimentation with the aid of the immobilized enzyme. The principle mathematical and numerical tools used in this work are : continuation, bifurcation, optimisation and collocation methods. These techniques provide highly precise description of the behaviour of the systems
Loum, Mor Absa. "Modèle de mélange et modèles linéaires généralisés, application aux données de co-infection (arbovirus & paludisme)". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS299/document.
We are interested, in this thesis, to the study of mixture models and generalized linear models, with an application to co-infection data between arboviruses and malaria parasites. After a first part dedicated to the study of co-infection using a multinomial logistic model, we propose in a second part to study the mixtures of generalized linear models. The proposed method to estimate the parameters of the mixture is a combination of a moment method and a spectral method. Finally, we propose a final section for studing extreme value mixtures under random censoring. The estimation method proposed in this section is done in two steps based on the maximization of a likelihood
Thon-Adjalin, Carolle. "Étude d'un système de transmission sur fibre optique plastique à saut d'indice". Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28166/28166.pdf.
Parhizkar, Masoumeh. "Modelling coupled surface water-groundwater flow and heat transport in a catchment in a discontinuous permafrost zone in Umiujaq, Northern Québec". Doctoral thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/66690.
Groundwater systems are expected to respond to climate change in a complex way. In cold regions, simulating the effect of climate change requires a state-of-the-art integrated hydrologic model. In this research, a fully coupled 3D numerical model has been developed to simulate groundwater-surface water flow and heat transport in a 2-km² catchment in Umiujaq, Nunavik (northern Quebec), Canada. The catchment is located in a discontinuous permafrost zone. It contains a lower aquifer, consisting of a thick coarse-grained glaciofluvial layer, overlain by a frost-susceptible silty marine unit and a perched upper aquifer. Detailed field investigations have been carried out to characterize the catchment, including its hydraulic and thermal properties and the subsurface geology. Three different calibration methods using the inverse calibration code PEST were used to calibrate the 3D flow model against measured hydraulic heads, assuming a fixed distribution of low hydraulic conductivity for discontinuous permafrost blocks. Heat transfer was not considered for this calibration. Results showed that using simplified calibration methods, such as the zoning method, is not efficient in this study area, which is highly heterogeneous. Using a more detailed calibration, such as the pilot-points method of PEST, gave a better fit to observed values. However, the computational time was significantly higher. In subsequent simulations, which included heat transport, different approaches for assigning initial temperatures during model spin-up were investigated. Results show that including the spin-up process in the simulations produces more realistic simulated temperatures. Furthermore, the spin-up improves the model fit to deeper subsurface temperatures because areas of the subsurface below the depth where seasonal surface temperature variations penetrate require longer simulation times to reach equilibrium with the applied boundary conditions. Applying the annual average surface temperature as the boundary condition to the heat transport simulation provided a better fit to observed values in the summer compared to winter. During winter, because of different snow thicknesses throughout the catchment, using a uniform surface temperature results in a poor fit to observed values. v Simulations show that warm water entering the subsurface increases the subsurface temperature in the recharge areas. As groundwater flows through the subsurface, it loses thermal energy. Therefore, discharging water is cooler than recharging water. This causes the rate of temperature rise to be lower in discharge areas than in recharge areas. The modelling results have helped provide insights into 3D simulation of coupled water flowheat transfer processes. Furthermore, it will help users of cryo-hydrogeological models in understanding effective parameters in development and calibration of model to develop their own site-specific models.
GAY, EMMANUEL. "Modelisation des systemes de transmission optique et des reseaux optiques". Rennes 1, 1995. http://www.theses.fr/1995REN10030.
N'zi, Yoboué Guillaume. "Élaboration d'une plate-forme de calculs numériques d'un modèle d'état à la base d'une approche phénoménologique : cas d'un four rotatif de clinker". Thesis, Université Laval, 2014. http://www.theses.ulaval.ca/2014/30553/30553.pdf.
This study develops a mathematical platform going from the establishment of a knowledge database to the setting up of an adaptive model. This has required a new approach of modeling of the clinker rotary kiln (CRK). Thus, a state model of distributed parameter systems, based on physico-chemical phenomena, was designed using partial differential equations. The model structure is based on three state variables which are: the gas, clinker temperatures and the clinker mass distributions, and are elaborated with the help of heat, pressure and mass balance equations. The model parameters are defined by the functions of three state variables. Moreover, the resulting state model, decomposed into five phenomenological zones of CRK, is used as a first step to define a set of Operating Functions (OFs). These OFs has also been decomposed into longitudinal distribution of CRK to replace the constant, unknown or unmeasured parameters. We develop an identification procedure based on phenomenological and dimensional analysis where the identification of operational functions (model parameters) was performed from a stationary state of the CRK. Once the restores state variables have been evaluated, the desired input (which is treated as the control of the CRK) can be more easily found by the proposed model than by simple trial and error. Moreover, the fact that the computation time, to estimate-calibrate the OFs above-mentioned, is very short, then this dynamic computation works faster than real-time. In summary, the cooperation and coordination in real-time between industrial computers and the CRK allows for an adaptable model, where each specific set of the OFs must be analyzed by its accuracy.
Benabdallah, Abdelhadi. "Modélisation mathématique d'oscillateurs supraconducteurs". Rouen, 1999. http://www.theses.fr/1999ROUES067.
Allard, Antoine. "Modélisation mathématique en épidémiologie par réseaux de contacts : introduction de l'hétérogénéité dans la transmissibilité". Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25738/25738.pdf.
Bazin, Antoine. "Modélisation numérique du retour de chaleur post-arrêt dans une turbine à gaz". Master's thesis, Université Laval, 2013. http://hdl.handle.net/20.500.11794/25410.
Heat soak-back is a phenomenon observed in many thermal applications including internal combustion engines. Post shutdown studies of these systems, particularly gas turbines, have shown that a massive heat wave could diffuse in the engine causing potential damage. As moving parts in the engine immobilize, heat diffuses freely from hotter to colder sections, including cavities such as the combustor. Primarily composed of free convection, the heat front in the combustor may cause premature coking in the top dead center injectors as the buoyant hot air tends to reach the upper section of the combustor. The following investigation implies computational fluid dynamics (CFD) simulation in order to predict the thermal behaviour and magnitude of this soak-back phenomenon inside a modified can combustor test rig and its potential consequences on the fuel delivery system. The numerical model will eventually be validated using experimentations with this combustor equipped with complementary thermal accumulation masses.
Poitau, Gwénael. "Contribution au développement d'un isolateur coplanaire à résonance par la méthode des Différences Finies dans le Domaine Temporel". Lyon, INSA, 2002. http://theses.insa-lyon.fr/publication/2002ISAL0036/these.pdf.
The objective of the work presented in this thesis is made of three points: the development of a modeling method ensuring the simulation of RF non reciprocal devices, some validations of this method then the optimization of a resonance coplanar isolator with the developed calculation code. In the first part of the thesis, we introduce some elements of non reciprocal effects physics. Then we explain the choice of the coplanar structure for integrating the isolator function in a microelectronics technology. Finally we introduce the method we have chosen for accomplishing this work: the Finite Difference Time Domain (FDTD). The second part of the thesis is made up of many validations done on our calculation code: rectangular waveguides, coplanar waveguides and dispersive materials simulations. Influences of spatial steps and effective permeability of magnetic materials are precisely studied. We also explain the way of managing non-uniform meshes as well as the dispersive nature of magnetic materials. Furthermore, we study non reciprocal effects around the gyromagnetic frequency in rectangular waveguides. The third part of the thesis is devoted to the optimization of the coplanar isolator. First, we do a parameters study with 3D1/2 simulations which allows us to quickly obtain results that we confront with corresponding technological issues. Finally, we simulate the isolator in three dimensions and highlight non reciprocal effects as well as the influence of the magnetic material location
Tendeng, Léna. "Etude de modèles de transmission de la Schistosomiase: Analyse mathématique, reconstruction des variables d'état et estimation des paramètres". Phd thesis, Université de Lorraine, 2013. http://tel.archives-ouvertes.fr/tel-00843687.
Tendeng, Ndéye Léna. "Étude de modèles de transmission de la Schistosomiase : analyse mathématique, reconstruction des variables d'état et estimation des paramètres". Electronic Thesis or Diss., Université de Lorraine, 2013. http://www.theses.fr/2013LORR0110.
The aim oh this thesis is the mathematical analysis and the estimation of the parameters of some metapopulation models for bilharzia transmission. We explain how the metapopulation models are built and give a full analysis of their stability. We compute the basic reproduction number R0. We show that if R0 is less than 1 then the Disease Free Equilibrium(DFE) is globally asymptotically stable. In case R0 is higher than 1, we prove the existence and the uniqueness of an endemic equilibrium which is globally asymptotically stable. At last,we suggest methods for the estimation of the states and the parameters for models. We build a numerical observer using the Moving Horizon State Estimation(MHSE) and an analitic one by the High Gain observer method. Applications of thes methods will be done on the Macdonald transmission model of bilharzia
Chaulet, Nicolas. "Modèles d'impédance généralisée en diffraction inverse". Phd thesis, Palaiseau, Ecole polytechnique, 2012. https://pastel.hal.science/docs/00/76/16/42/PDF/chaulet.pdf56).
The main objective of this thesis is to use asymptotic models for the resolution of inverse electromagnetic scattering problems. We consider in particular the case of generalized impedance conditions that are models for thin coatings or strongly absorbing media. The term "generalized impedance" signifies that the boundary condition involves a surface operator. The so-called classical impedance boundary conditions is a particular case of generalized impedance boundary condition where the operator reduces to the multiplication by a function. In the inverse problems context, the use of such approximate models simplifies the numerical resolution as well as the mathematical analysis. In the literature a lot of studies focus on inverse scattering with classical impedance boundary conditions, we extend them to the case of more complex surface operators containing surface derivatives for example. An important part of the thesis deals the application of optimization methods to find both a shape and parameters that characterize the boundary operator. Among others, we present the computation of the shape derivative for Helmholtz' and Maxwell's equations. Numerical illustrations of shape reconstruction and identification of boundary coefficients are also provided. We complement this work by studying a qualitative method - the factorization method - to retrieve a shape with a general form of generalized impedance boundary conditions. In relation with qualitative methods, we investigated the use of the so-called interior transmission eigenvalues associated with thin layer structures to obtain information about the layer thickness and properties. In this view, we derived and justified the full asymptotic development of the first interior transmission eigenvalue with respect to the small thickness of the layer. This development provides a simple procedure to compute the thickness of the layer from multi-static scattered field data
Voillemont, Jean-Charles. "Caractérisation par micro-sismicité induite des milieux poreux fracturés : modélisations par la méthode des lignes de courant d'un site géothermique HDR (Soultz-sous-Forêts, France)". Vandoeuvre-les-Nancy, INPL, 2003. http://www.theses.fr/2003INPL040N.
Visco, Comandini Filippo. "Some inverse cattering problems on star-shapped graphs : application to fault detection on electrical transmission line networks". Versailles-St Quentin en Yvelines, 2011. http://www.theses.fr/2011VERS0035.
In this thesis, having in mind applications to the fault-detection/diagnosis of electrical networks, we consider some inverse scattering problems for the Zakharov-Shabat equations and time-independent Schrödinger operators over star-shaped graphs. The first chapter is devoted to describe reflectometry methods applied to electrical networks as an inverse scattering problems on the star-shaped graphs. Modeled by the telegrapher’s equations, reflectometry experiments can be written as inverse scattering problems for Schrödinger operator in the lossless case and for Zakharov-Shabat system for the lossy transmission network. In Chapter 2 we introduce some elements of the inverse scattering theory for 1 d Schrödinger equations and the Zakharov-Shabat system. We recall the basic results for these two systems and we present the state of art of scattering theory on network. The third chapter deals with some inverse scattering for the Schrödinger operators. We prove the identifiability of the geometry of the star-shaped graph: the number of the edges and their length. Next, we study the potential identification problem by inverse scattering. In the last chapter we focus on the inverse scattering problems for lossy transmission star-shaped network. We prove the identifiability of some geometric informations by inverse scattering and we present a result toward the identification of the heterogeneities, showing the identifiability of the loss line factor
Chaulet, Nicolas. "Modèles d'impédance généralisée en diffraction inverse". Phd thesis, Ecole Polytechnique X, 2012. http://pastel.archives-ouvertes.fr/pastel-00761642.
Gomes, Sebastião Cícero Pinheiro. "Précision de la transmission du couple par un moto-réducteur électrique : modélisation et commande d'un bras rigide ou flexible avec compensation du frottement". Toulouse, ENSAE, 1992. http://www.theses.fr/1992ESAE0020.
Houni, Karim. "Modélisation et étude de la transmission d'information par codes graphiques". Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10002/document.
Graphical Codes such as barcodes and 2D codes are a leading technology in identification and EDI. Displaying and reading these black and white pictograrns is equivalent to a singular digital communication system such that we drove our study according to information theory. From radiometry and optics principles, we've proposed a transmission channel model as a linear filter with Gaussian noise. Model parameters are thus function of code and camera characteristics, positioning and radiating power. System performances are evaluated with the computation of average mutual information (AMI). ln the 1D case (barcodes), AMI is estimated with a version of the BCJR Forward recursion by using channel markovianity. AMI is then an objective measure from which we define a theoretic depth of field and spatial resolution. These two criteria complement their geometrical equivalent by considering channel distortions and noise. ln the 2D case, we've shown that the model imply that the probability distribution of data knowing observations (a posteriori) is a Gibbs random field. We have thus highlighted that the evaluation of system's information rate is equivalent to the estimation of the random field free energy. The perspectives of the works are: adding colour to the codes, channel coding and the application of turbo principles
Rebaiaia, Mohamed-Larbi. "A contribution to the evaluation and optimization of networks reliability". Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28436/28436.pdf.
Efficient computation of systems reliability is required in many sensitive networks. Despite the increased efficiency of computers and the proliferation of algorithms, the problem of finding good and quickly solutions in the case of large systems remains open. Recently, efficient computation techniques have been recognized as significant advances to solve the problem during a reasonable period of time. However, they are applicable to a special category of networks and more efforts still necessary to generalize a unified method giving exact solution. Assessing the reliability of networks is a very complex combinatorial problem which requires powerful computing resources. Several methods have been proposed in the literature. Some have been implemented including minimal sets enumeration and factoring methods, and others remained as simple theories. This thesis treats the case of networks reliability evaluation and optimization. Several issues were discussed including the development of a methodology for modeling networks and evaluating their reliabilities. This methodology was validated as part of a radio communication network project. In this work, some algorithms have been developed to generate minimal paths and cuts for a given network. The generation of paths and cuts is an important contribution in the process of networks reliability and optimization. These algorithms have been subsequently used to assess reliability by a method based on binary decision diagrams. Several theoretical contributions have been proposed and helped to establish an exact solution of the stochastic networks reliability in which edges and nodes are subject to failure using factoring decomposition theorem. From this research activity, several tools have been implemented and results clearly show a significant gain in time execution and memory space used by comparison to many other implementations. Key-words: Reliability, Networks, optimization, binary decision diagrams, minimal paths set and cuts set, algorithms, Birnbaum performance index, Networks, radio-telecommunication systems, programs.
Rahimi, Mohammad. "Modélisation de l'effet du couvert de neige sur les transferts thermiques sol-atmosphère". Doctoral thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/27410.
This work focused on the modeling of the effect of a seasonal snow cover on the thermal behavior of large engineering structures built in the northern regions, and its application for structures built with materials of large porometry. Nowadays, the presence of snow is often neglected in thermal numerical simulations, except for investigating the phenomenon of avalanches or production of water after snowmelt in the mountainous regions, while using conceptual models or very detailed models based on physics. In the industry, modeling a large structure by detailed models have two principals drawback. First, because of large numbers of partial differential equations and parameters, which are sometimes difficult to estimate. The introduction of snow as a medium in the computational domain also imposes great challenges for the continuous simulations for consecutive years, because seasonal snow is present only a few months a year and the domain representing the snow must be removed after melting. In this regard, the main objective of this research is to develop a new tool for the modeling of snow thermal effect on geotechnical structure continuously for several years that can also be applied in simple practical cases. For this, transfers of the heat and mass in snow are first studied to identify the most important transfer modes that significantly affect soil temperature. Then, a numerical tool using the FlexPDE software has been established to model the heat transfer by conduction and convection between soil, snow and atmosphere continuously over the entire year. This tool also considers the effect of snow (close or open boundary) on the air convection in the coarse granular materials, the rain effect and the water phase change in the energy balance of the snow cover. This tool uses the surface energy balance as the Neumann boundary condition for temperature. The tool is also served for thermal analysis of an embankment dam and demonstrates the presence of convection cells and the influence of the air convection on the heat extraction of foundation. Another purposes of this research is to establish a simple and accurate model of thermal conductivity for all types of snow, including artificially manipulated and compacted snow. Most of the existing model of the snow’s thermal conductivity are developed through regression techniques which have the drawback of not respecting the physical limits of snow. To integrate these physical limits in a simple model, the relative thermal conductivity concept is used in this study. This model is verified with published data and further validated with the results of the tests performed in the laboratory of Laval University. The proposed model estimates the thermal conductivity of all types of snow with great reliability.
Tendeng, Ndéye Léna. "Étude de modèles de transmission de la Schistosomiase : analyse mathématique, reconstruction des variables d'état et estimation des paramètres". Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0110/document.
The aim oh this thesis is the mathematical analysis and the estimation of the parameters of some metapopulation models for bilharzia transmission. We explain how the metapopulation models are built and give a full analysis of their stability. We compute the basic reproduction number R0. We show that if R0 is less than 1 then the Disease Free Equilibrium(DFE) is globally asymptotically stable. In case R0 is higher than 1, we prove the existence and the uniqueness of an endemic equilibrium which is globally asymptotically stable. At last,we suggest methods for the estimation of the states and the parameters for models. We build a numerical observer using the Moving Horizon State Estimation(MHSE) and an analitic one by the High Gain observer method. Applications of thes methods will be done on the Macdonald transmission model of bilharzia
Souissi, Adel. "Développement des méthodes numériques et expérimentales pour l'étude du champ acoustique de transducteurs ultrasonores en présence d'une interface fluide-solide (réflexion, transmission)". Compiègne, 1987. http://www.theses.fr/1987COMPD096.
Viet, Anne-France. "Propagation du virus de la diarrhée virale bovine dans un troupeau laitier : modélisation stochastique individu-centrée pour une population structurée en groupes et d'effectif contrôlé". Rennes 1, 2003. http://www.theses.fr/2003REN1A012.
Guerni, Mahoui Malika. "L'impact des objets typés sur le modèle transactionnel à effets différés". Montpellier 2, 1995. http://www.theses.fr/1995MON20147.
Delourme, Bérangère. "Modèles et asymptotiques des interfaces fines et périodiques en électromagnétisme". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2010. http://tel.archives-ouvertes.fr/tel-00650354.
Tiganj, Zoran. "On the pertinence of a numerical transmission model for neural information". Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2011. http://tel.archives-ouvertes.fr/tel-00699623.
Boucher, Jérôme. "Modélisation réaliste de l'activation des récepteurs dans les cellules excitatrices de l'hippocampe". Thesis, Université Laval, 2014. http://www.theses.ulaval.ca/2014/30677/30677.pdf.
Pardonche, Jean-François. "Systèmes de transmission sans fil multi-émetteurs, multi-récepteurs pour des applications transports : étude des modèles de canal de propagation". Lille 1, 2004. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2004/50376-2004-5-6.pdf.
La pertinence d'un modèle de canal MIMO dépend donc de sa capacité à traduire le degré de corrélation dans le canal. Différents types de modèles de canal MIMO sont présentés dans ce mémoire: les modèles déterministes et les modèles stochastiques. Nous insistons plus particulièrement sur les principes de' construction des modèles stochastiques parce qu'ils ne demandent pas une description de l'environnement et qu'ils sont simples d'utilisation. Ils sont fondés sur le calcul de la corrélation dans le canal. Ces modèles de canal sont comparés à partir de mesures réalisées dans différents environnements, un tunnel de métro et deux environnements "indoor". L'influence des différents environnements sur la capacité d'un canal MIMO est présentée. Il ressort de cette comparaison que les modèles qui décrivent le mieux le comportement du canal MIMO quel que soit l'environnement sont ceux qui reposent sur la matrice de covariance du canal qui permet de prendre en compte de façon intrinsèque à la fois la puissance et la phase des coefficients du canal. La transmission d'un flux vidéo issu d'un système de vidéo surveillance à l'intérieur d'un bus vers un poste de contrôle distant est simulée sous Matlab. Les différents algorithmes implémentés sont décrits et nous rappelons leurs performances. Le meilleur modèle de canal identifié est appliqué sur des mesures réalisées en environnement semi-urbain. Nous montrons le gain apporté par les systèmes MIMO sur les débits ou la robustesse de la liaison sans fil et l'influence des caractéristiques du canal de propagation sur les performances
Bélanger, Jean. "Caractérisation des transferts hygrothermiques dans une enveloppe de bâtiment en bois par la résolution d'un problème inverse par l'optimisation des propriétés physiques des matériaux". Master's thesis, Université Laval, 2021. http://hdl.handle.net/20.500.11794/69706.
Crévits, Yvan. "Caractérisation et commande des entraînements polyphasés en mode dégradé d’alimentation". Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10049/document.
This work describes a constant torque control method in a multiphase permanent magnet synchronous machine under open-circuited fault supply conditions. The chapter one draws up a state of the art of the modellings and the controls of the multiphase machines used in electromechanical drive, in normal mode as degraded supply mode. The multiphase modelling methodologies of the L2EP laboratory applied to multiphase machines reveals the decomposition in several fictitious machines and their control are deduced from the Energetic Macroscopic Representation (EMR) for the two supply modes. It is finally established that these methods of torque correction are unsuited for a large number of phases. The chapter two establishes a causal modelling of the drive usable in normal and fault mode. Degradation generates frequency disturbances of the currents in the fictitious machines. The torque correction then consists in adapting the numbers of degrees of freedom of the command and the degraded drive, then to eliminate these disturbances. At low speed, pi-controllers tuned for the normal operating are sufficient, but better performances at high speed use additional resonant controllers. The not corrected disturbed currents are rejected into a fictitious machine that does not produce any torque thanks to a suitable emf profile. The validation of the degradation model and the methodology on a seven-phase machine answering the assumptions are satisfactory. The method assessment of torque re-establishment is finally drawn up for a machine designed for fault-mode operating and evokes the less specific case of machines
Kouegou, Kamen Boris. "Grandes déviations dans des modèles de biologie et des épidémies". Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0619.
We are interested in large deviations principle for Markov jump processes and it applications in biology and Eepidemiology. We prove using a new approach the lower bound of the large deviations principle for such general processes and we also write the well known upper bound. We apply these result to a malaria transmission model in epidemiology and give estimate to the exit time from the domain of attraction of the endemic equilibrium. We also apply the approach to obtain large deviations estimates for a model of evolutionary biology which describes the effect of continuous environment changes on the fitness of a given population. Finally we treat a deterministic spatially explicit model of cholera epidemics, propose a stochastic modelling and establish a law of large number. We end by giving large deviations estimates for the stochastic process