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Durot, Cécile. "Asymptotique fine pour l'estimateur isotonique en régression et méthodes de jackknife : applications à la comparaison de courbes de croissance". Paris 11, 1997. http://www.theses.fr/1997PA112007.
Pełny tekst źródłaFontez, Bénédicte. "Test d'adéquation des résidus pour la régression non-linéaire. Application aux courbes de croissance en foresterie". Montpellier 2, 2001. http://www.theses.fr/2001MON20005.
Pełny tekst źródłaMoussambi, Membetsi Hermance. "Croissance par la méthode Czochralski de cristaux non linéaires de borate : premières caractérisations". Metz, 2004. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2004/Moussambi_Membetsi.Hermance.SMZ0407.pdf.
Pełny tekst źródłaThe low temperature phase of baryum metaborate possesses non linear optical properties (NLO) that offer advantages regarding the generation of U. V. By frequency doubling. Lithium tetraborate is currently being studied for application to linear systems. The work presented concerns the growth of these materials and a first evaluation of their potential. The Czochralski method was used et lab to obtain crystals directly from a pure melt. The production of good quality crystals resulted from some key points. The initial choice of starting materials and the synthesis of powders from BBO in particular. The setup of thermal parameters such as temperature gradients and the temperature at the surface of the melt, as well as the adaptation of our equipement to the Czochralski growth technique for each material. The preparation of samples using polishing techniques respecting the hygroscopy of borate crystals and using original orientation techniques of BBO samples by micro-Raman spectroscopy and conoscopy. Original characterizations were made from the obtained samples. From absorption measures and effective ONL coefficients from Second Harmonic Generation, (SHG) we were able to not only validate the choice of -BBO crystal growth technique, but also perform a comparison with crystals from the liquid crystal growth technique, the most widely used method in industry. The obtained results are very encouraging regarding the generation of U. V. D by SHG. LTB crystals were available to the laboratory for characterization by Raman spectroscopy or by electro-optical measures
Vera, Carine. "Modèles linéaires mixtes multiphasiques pour l'analyse de données longitudinales : Application à la croissance des plantes". Montpellier 2, 2004. http://www.theses.fr/2004MON20161.
Pełny tekst źródłaSaunal, Christian. "Modélisation de la cinétique de croissance de cristaux de KTiOPO4 de grandes dimensions : importance de la sursaturation et de l'hydrodynamique". Nancy 1, 1995. http://www.theses.fr/1995NAN10277.
Pełny tekst źródłaRibot, Magali. "Étude théorique de méthodes numériques pour les systèmes de réaction-diffusion; application à des équations paraboliques non linéaires et non locales". Phd thesis, Université Claude Bernard - Lyon I, 2003. http://tel.archives-ouvertes.fr/tel-00004563.
Pełny tekst źródłaCayemitte, Jean-Marie. "Accumulation des biens, croissance et monnaie". Thesis, Paris 2, 2014. http://www.theses.fr/2014PA020001/document.
Pełny tekst źródłaThis thesis constructs a theoretical model that renews the traditional approach of the market equilibrium. By introducing into the neoclassical paradigm the principle of preference for quantity, it optimally generates inventories within a competitive market. The results are very important since they explain both the emergence of unsold goods and the existence of economic cycles. In addition, it studies the optimal behavior of a monopolist whose the market power depends not only on the quantity of displayed goods but also that of goods that the main consumer is willing to buy. Contrary to the traditional assumption that the monopolist chooses price or quantity that maximizes its profit, through a generalized Lerner index (GLI) it attracts customers’ demand by both the price and the quantity of displayed goods. Whatever the market structure, the phenomenon of inventory accumulation appears in the economy. Furthermore, it has the advantage of explicitly explaining impulse purchases untreated by economics. To check the robustness of the results,the theoretical model is fitted to U.S. data. Due to its nonlinearity, the Gauss-Newtonmethod is appropriate to highlight the impact of consumers’ preference for quantity on production and accumulation of goods and consequently GDP forecast. Finally, this thesis builds a two-country overlapping generations (OLG) model which extends the dynamic OLG equilibrium to a frictionless dynamic OLG gamma-equilibrium. Based on the cash-inadvance constraint, it highlights the conditions of over-accumulation of capital and welfare implications of capital mobility in a context of accumulation of stock of unsold goods
Zhou, Chao. "Model Uncertainty in Finance and Second Order Backward Stochastic Differential Equations". Palaiseau, Ecole polytechnique, 2012. https://pastel.hal.science/docs/00/77/14/37/PDF/Thesis_ZHOU_Chao_Pastel.pdfcc.
Pełny tekst źródłaThe main objective of this PhD thesis is to study some financial mathematics problems in an incomplete market with model uncertainty. In recent years, the theory of second order backward stochastic differential equations (2BSDEs for short) has been developed by Soner, Touzi and Zhang on this topic. In this thesis, we adopt their point of view. This thesis contains of four key parts related to 2BSDEs. In the first part, we generalize the 2BSDEs theory initially introduced in the case of Lipschitz continuous generators to quadratic growth generators. This new class of 2BSDEs will then allow us to consider the robust utility maximization problem in non-dominated models. In the second part, we study this problem for exponential utility, power utility and logarithmic utility. In each case, we give a characterization of the value function and an optimal investment strategy via the solution to a 2BSDE. In the third part, we provide an existence and uniqueness result for second order reflected BSDEs with lower obstacles and Lipschitz generators, and then we apply this result to study the problem of American contingent claims pricing with uncertain volatility. In the fourth part, we define a notion of 2BSDEs with jumps, for which we prove the existence and uniqueness of solutions in appropriate spaces. We can interpret these equations as standard BSDEs with jumps, under both volatility and jump measure uncertainty. As an application of these results, we shall study a robust exponential utility maximization problem under model uncertainty, where the uncertainty affects both the volatility process and the jump measure
Gökcan, Hatice. "Modélisation moléculaire de la réactivité de GABA-AT : de petits modèles représentatifs à la protéine complète, de la mécanique moléculaire à la chimie quantique, du statique au dynamique". Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0130/document.
Pełny tekst źródłaUnderstanding enzymes and their catalytic mechanisms is very important in order to develop more effective drugs having little to no side effects. In order to decipher the catalytic behavior of enzymes, different approaches such as QM, MM-MD, and QM/MM can be used and their results can be correlated. The main aim of this thesis is to get a deeper understanding of the mechanistic insights of the reactivity and of the dynamics of the pyridoxal-5-phosphate (PLP) dependent enzyme y-aminobutyric acid aminotransferase (GABA-AT). Because GABA-AT resembles many other PLP-dependent enzymes, understanding it could be of importance for the broad community of biochemists and computational chemists who study such class of proteins. Our work has consisted of five stages to pursuit the comprehension of GABA-AT. First, the reaction and the preferred binding mode of the natural substrate GABA has been elucidated with different isomers by means of model systems with DFT. Second, the dynamics and the behavior of the enzyme has been studied with MM-MD through the use of apoenzyme, holoenzyme and holoenzyme with an inactivator. Third, the effect of the active site residues in the inactivation mechanism has been investigated with the modelling of clusters at the QM level involving key residues. Fourth, new diagonalization routines for the SEBOMD (SemiEmpirical Born-Oppenheimer Molecular Dynamics) approach implemented in the Amber suite of programs, have been incorporated using LAPACK and SCALAPACK libraries, tested and evaluated to optimize the diagonalization procedure of the Fock matrix. Fifth, reaction free energies of PLP containing systems have been investigated with SEBOMD simulations
Rame, Jérémy. "Recherche et élaboration de nouveaux matériaux pour les applications laser non-linéaires du moyen infrarouge". Electronic Thesis or Diss., Paris 6, 2014. http://www.theses.fr/2014PA066716.
Pełny tekst źródłaMid-infrared laser sources have attracted a particular attention due to their potential applications in different fields, such as remote chemical sensing or infrared counter-measures for civilian or military aircrafts safety. One way to produce such sources is the down conversion process in optical parametric oscillators using nonlinear crystals. AgGaGeS4 is a promising candidate for these applications. The chemical synthesis and crystal growth steps of this material processing are presented in this study. Ingots with 28 mm diameter and 70 mm length were grown. The key issue of AgGaGeS4 processing is the control of melt decomposition at high temperature due to the high volatility of GeS2. The influence of GeS2 volatility on melt stoichiometry during the AgGaGeS4 processing is outlined, and solutions to improve crystals quality by controlling this volatility are presented. Otherwise, we present the development of a device which aim to improve the chemical synthesis process by controlling the pressure variations during the chemical reaction. Main interests of this device are to study the chemical reaction which occurs during the process and control the pressure variations during the chemical reaction. Furthermore, ab initio calculations were performed in order to study the properties of ZnGeP2 which is a benchmark material for mid-IR laser conversion. The effect of ionic substitution on ZnGeP2 properties was studied. Moreover, ZnGeP2:Sn crystals were elaborated and characterized. It was demonstrated that ionic substitutions with tin allowed significantly improvements on the crystal transmission around the pump wavelength at 2.05 μm
Riah, Rachid. "Théorie des ensembles pour le contrôle robuste des systèmes non linéaires : Application à la chimiothérapie et les thérapies anti-angiogéniques". Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAT090/document.
Pełny tekst źródłaThis thesis aims at using the mathematical modeling with advanced control tools to guide therapies for the contraction of the tumor. The aims of this thesis are the contribution to the development of the set-theoretic methods for robust control of nonlinear systems and the development of analytical tools for the analysis and control of tumor growth in presence of chemotherapy and/oranti-angiogenic therapy. Generically, in the context of control theory, techniques that are theoretically based on some properties of subsets of the system state space could be referred as set-theoretic methods.In the first part, we review the definitions, concepts and tools of the existing set-theoretic methods in the literature to respond effectively to the control issues of linear and nonlinear systems with hard constraints and uncertainties. In this context, we are interested in two properties of sets that are invariance and contractiveness. The problems associated with the stability of the systems may be formulated in terms of calculation of their domain of attraction. For development purposes, we recall methods from the literature for characterizing these domains of attraction for linear and nonlinear systems. An important application of these methods is the control of tumor growth in the presence of different treatments. For this application, several constraints can be imposed in order to avoid the patient intoxications during the treatments and the set-theoretic methods can consider easily these constraints. For this latter application, we propose a methodology to estimate the domains of attraction for the mathematical models chosen to simulate the tumor growth.In the second part, we propose set-theoretic methods for the characterization of the domains ofattraction for linear and nonlinear uncertain systems. At the beginning, we develop sufficient conditions for the invariance and contractiveness of an ellipsoid for saturated systems. These conditions allow implicitly determining a local Lyapunov function. We will show that the proposed approach is less conservative than those in the literature, and we give an algorithm for characterizing the invariant ellipsoids. For uncertain nonlinear systems, we develop a sufficient condition for the robust controlled invariance in the case of parametric uncertainties. A method based on this condition is developed for characterizing the domains of attraction for nonlinear systems with these uncertainties. Then we focus on the study of nonlinear systems with additive uncertainties, and we also give a method for the characterization of their domains of attraction. These methods are easily treatable using convex optimization tools.In the third part, we develop numerical tools for characterizing the domains of attraction for themodels of tumor growth in the presence of treatments, particularly chemotherapy and anti-angiogenictreatment. These domains contain all the states of the patients for whom effective treatment protocols exist. In this context, we consider that the models are uncertain and in particular the parameters that are unknown in practice. These tools are based on the methods developed in this thesis. Several useful informations for effective tumor therapy can be extracted from these domains
Dianzinga, Mamy Rivo. "N-representable density matrix perturbation theory". Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0285/document.
Pełny tekst źródłaWhereas standard approaches for solving the electronic structures present acomputer effort scaling with the cube of the number of atoms, solutions to overcomethis cubic wall are now well established for the ground state properties, and allow toreach the asymptotic linear-scaling, O(N). These solutions are based on thenearsightedness of the density matrix and the development of a theoreticalframework allowing bypassing the standard eigenvalue problem to directly solve thedensity matrix. The density matrix purification theory constitutes a branch of such atheoretical framework. Similarly to earlier developments of O(N) methodology appliedto the ground state, the perturbation theory necessary for the calculation of responsefunctions must be revised to circumvent the use of expensive routines, such asmatrix diagonalization and sum-over-states. The key point is to develop a robustmethod based only on the search of the perturbed density matrix, for which, ideally,only sparse matrix multiplications are required. In the first part of this work, we derivea canonical purification, which respects the N-representability conditions of the oneparticledensity matrix for both unperturbed and perturbed electronic structurecalculations. We show that this purification polynomial is self-consistent andconverges systematically to the right solution. As a second part of this work, we applythe method to the computation of static non-linear response tensors as measured inoptical spectroscopy. Beyond the possibility of achieving linear-scaling calculations,we demonstrate that the N-representability conditions are a prerequisite to ensurereliability of the results
Mainka, Jérôme. "Méthodes hybrides en programmation linéaire". Paris 9, 1996. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=1996PA090019.
Pełny tekst źródłaSavoundararadja, Ravindranath. "Évaluation comparative des méthodes multicritères de régression ordinale : méthodes UTA et méthodes MORALS". Paris 6, 1987. http://www.theses.fr/1987PA066616.
Pełny tekst źródłaMottard, Patrick. "Méthodes semi-analytiques en vibration non linéaire". Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/27781/27781.pdf.
Pełny tekst źródłaBaey, Charlotte. "Modélisation de la variabilité inter-individuelle dans les modèles de croissance de plantes et sélection de modèles pour la prévision". Phd thesis, Ecole Centrale Paris, 2014. http://tel.archives-ouvertes.fr/tel-00985747.
Pełny tekst źródłaMarchetti, Charles-Michel. "Méthodes de perturbations singulières en filtrage non linéaire". Aix-Marseille 1, 1986. http://www.theses.fr/1986AIX11023.
Pełny tekst źródłaOrban, Dominique. "Méthodes de points intérieurs pour l'optimisation non-linéaire". Toulouse, INPT, 2001. http://www.theses.fr/2001INPT012H.
Pełny tekst źródłaWieduwilt, Erna K. "Quantum mechanics-based methods for the refinement of crystal structures and the analysis of non-covalent interactions". Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0167.
Pełny tekst źródłaIn the work presented in this thesis, extremely localized molecular orbitals (ELMOs) were used as electronic LEGO building blocks to accomplish mainly two goals: (i) obtaining more accurate X-ray crystal structures for small and large systems, and (ii) analyzing non-covalent interactions in biomolecules. In fact, ELMOs are molecular orbitals that are strictly localized on small molecular fragments. Due to this strict localization, they may be computed on small molecules, stored in databases and then transferred to larger systems to reconstruct their wavefunctions and electron densities. To this end, we exploited the ELMO libraries, which contain the ELMOs for all the elementary fragments (atoms, bonds and functional groups) of the twenty natural amino acids. In situations where a higher accuracy was needed, we used the QM/ELMO embedding technique, in which the crucial part of the system under exam is treated at a higher quantum mechanical level, while the rest is described using frozen ELMOs. Concerning the first of the goals mentioned above, it is important to note that standard crystallographic refinements are based on the so-called independent atom model (IAM), which approximates the electron density as a sum of spherically averaged atomic densities. However, the element-hydrogen bond lengths resulting from IAM refinements are systematically too short. A method that solves this problem is the Hirshfeld atom refinement (HAR), a technique based on directly computing the electron density for the molecule under exam using quantum mechanical calculations. For small molecules, HAR has been proven to give element-hydrogen bond lengths that are in very good agreement with neutron reference values. However, for large systems, the applicability of the traditional HAR method is limited because the underlying fully QM calculations become computationally too expensive. Therefore, in the work presented in this thesis, the ELMO libraries and the QM/ELMO techniques have been coupled with the HAR method to refine large systems and also to obtain more accurate structures of small molecules. Furthermore, the necessity of using post-HF methods for HAR has been also evaluated. Concerning the second goal addressed in this dissertation, a similar problem as the one met in X-ray crystallography also arises in the analysis of non-covalent interactions. In fact, also the non-covalent interaction (NCI) and independent gradient model (IGM) techniques, which are commonly applied in analyses of non-covalent interactions, crucially depend on the computation of the electron density. Therefore, to analyze non-covalent interactions in large systems, both techniques had to resort to promolecular electron densities, which are the same densities used in the IAM. However, also in the cases of NCI and IGM analyses, these densities provide biased results. To overcome this drawback, we have coupled both methods with the ELMO libraries, giving rise to the NCI-ELMO and IGM-ELMO techniques, which were then applied to identify, classify and approximately quantify non-covalent interactions in polypeptides and proteins
Gloria, Antoine. "Modélisation et méthodes numériques multiéchelles en élasticité non linéaire". Phd thesis, Ecole des Ponts ParisTech, 2007. http://tel.archives-ouvertes.fr/tel-00166171.
Pełny tekst źródłapour l'homogénéisation de fonctionnelles intégrales utilisées en élasticité non linéaire. Ces mé-
thodes couplent, au niveau mésoscopique, un matériau hyperélastique hétérogène ou un réseau de
liens en interaction, avec, au niveau macroscopique, un modèle d'élasticité non linéaire. La loi de
constitution macroscopique est obtenue par la résolution de problèmes mésoscopiques, continus ou
discrets. Aux chapitres 1, 2 et 3 on introduit les modèles mécaniques et les outils mathématiques et
numériques utilisés par la suite. Aux chapitres 5, 6 et 7, on présente une méthode directe de réso-
lution numérique du comportement homogénéisé d'un matériau composite périodique en grandes
déformations et un cadre général pour l'analyse des méthodes d'homogénéisation numérique. On
démontre notamment la convergence de méthodes numériques classiques sous des hypothèses gé-
nérales ainsi qu'un résultat de correcteur numérique. On étend enfin les résultats au couplage avec
des méthodes de sur-échantillonnage. Aux chapitres 8, 9 et 10, nous considérons une modélisation
mésoscopique par un système discret. Nous étudions d'abord un problème de G-fermeture pour un
réseau de résistances. Au chapitre suivant nous démontrons un résultat de représentation intégrale
pour l'énergie d'un système de spins en interaction. Enfin, nous dérivons un modèle hyperélastique
continu à partir d'un réseau stochastique de points en interaction, et l'appliquons pour démontrer
la convergence de modèles discrets développés en mécanique. Dans une dernière partie, chapitre 11,
nous présentons une nouvelle méthode numérique pour résoudre des problèmes d'interaction fluide
structure, où la structure est décrite par une coque tridimensionnelle.
Gerges, Youssef. "Méthodes de réduction de modèles en vibroacoustique non-linéaire". Phd thesis, Université de Franche-Comté, 2013. http://tel.archives-ouvertes.fr/tel-00933423.
Pełny tekst źródłaHohweiller, Tom. "Méthodes de décomposition non-linéaire pour l'imagerie X spectrale". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI097.
Pełny tekst źródłaSpectral tomodensitometry is a new emerging x-ray imaging modality. If the dual-energy principle was already known for quite some time, new developments on photon-counting detectors now allowing acquiring more energy bins than before. This modality allows reducing some artifacts presents in x-ray imaging, such as beam hardening, but mostly to decompose the data into the chemical composition of the imaged tissue. It also enables the use of new markers (i.e. gold) with an energic discontinuity. The use of these markers also allows to locate and quantify them in the patient, granting great potential for medical imaging. Decomposition in the projection domain followed by a tomographic reconstruction is a classical processing for those spectral data. However, decomposition methods in the projection domain are unstable for a high number of energy bins. Classical calibration technic is numerically unstable for more than two energy bins. This thesis aims to developed new material decomposition methods in the projections domains. After expressing the spectral forward model, the decomposition problem is expressed and dealt as a non-linear inverse problem. It will be solved by minimizing a cost function composed by a term characterizing the fidelity of the decomposition regarding the data and an \textit{a priori} of the decomposed material maps. We will firstly present an adaptation of the cost function that takes into account the Poissonian noise on the data. This formulation allows having better decomposed maps for a high level of noise than classical formulation. Then, two constrained algorithms will be presented. The first one, a projected Gauss-Newton algorithm, that enforces positivity on the decomposed maps, allows having better decomposed maps than an unconstrained algorithm. To improve the first algorithm, another one was developed that also used an egality constrain. The equality allows having images with fewer artifacts than before. These methods are tested on a numerical phantom of a mouse and thorax. To speed up the decomposition process, an automatic choice of parameters is presented, which allow faster decomposition while keeping good maps. Finally, the methods are tested on experimental data that are coming from a spectral scanner prototype
Kaboul, Hanane. "Méthodes d'intégration produit pour les équations de Fredholm de deuxième espèce : cas linéaire et non linéaire". Thesis, Lyon, 2016. http://www.theses.fr/2016LYSES024.
Pełny tekst źródłaThe product integration method has been proposed for solving singular linear Fredholm equations of the second kind whose exact solution is smooth, at least continuous. In this work, we adapt this method to the case where the solution is only integrable. We also study the nonlinear case in the space of integrable functions. Then, we propose a new version of the method in the nonlinear framework : we first linearize the eqaution by a Newton type method and then discretize the Newton iterations by the product integration method
Omheni, Riadh. "Méthodes primales-duales régularisées pour l'optimisation non linéaire avec contraintes". Thesis, Limoges, 2014. http://www.theses.fr/2014LIMO0045/document.
Pełny tekst źródłaThis thesis focuses on the design, analysis, and implementation of efficient and reliable algorithms for solving nonlinearly constrained optimization problems. We present three new strongly primal-dual algorithms to solve such problems. The first feature of these algorithms is that the control of the iterates is done in both primal and dual spaces during the whole minimization process, hence the name “strongly primal-dual”. In particular, the globalization is performed by applying a backtracking line search algorithm based on a primal-dual merit function. The second feature is the introduction of a natural regularization of the linear system solved at each iteration to compute a descent direction. This allows our algorithms to perform well when solving degenerate problems for which the Jacobian of constraints is rank deficient. The third feature is that the penalty parameter is allowed to increase along the inner iterations, while it is usually kept constant. This allows to reduce the number of inner iterations. A detailed theoretical study including the global convergence analysis of both inner and outer iterations, as well as an asymptotic convergence analysis is presented for each algorithm. In particular, we prove that these methods have a high rate of convergence : superlinear or quadratic. These algorithms have been implemented in a new solver for nonlinear optimization which is called SPDOPT. The good practical performances of this solver have been demonstrated by comparing it to the reference codes IPOPT, ALGENCAN and LANCELOT on a large collection of test problems
El, Ouafdi Ahmed Fouad. "Méthodes primales-duales pour la programmation non linéaire non convexe". Mémoire, Université de Sherbrooke, 2003. http://savoirs.usherbrooke.ca/handle/11143/4589.
Pełny tekst źródłaGloria, Antoine. "Modélisation et méthodes numériques multi-échelles en élasticité non linéaire". Marne-la-vallée, ENPC, 2007. http://www.theses.fr/2007ENPC0710.
Pełny tekst źródłaGosselet, Pierre. "Méthodes de décomposition de domaine et méthodes d'accélération pour les problèmes multichamps en mécanique non-linéaire". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2003. http://tel.archives-ouvertes.fr/tel-00277771.
Pełny tekst źródłaNous retenons une stratégie éléments-finis associée à un solveur Newton-Raphson et une décomposition de domaine sans recouvrement combinée à un solveur de Krylov.
Nous proposons des améliorations pour adapter ces approches à nos problèmes, puis pour des cas plus exigeants nous définissons une nouvelle approche de décomposition de domaine, appelée approche hybride, permettant de mieux respecter la physique des phénomènes et unifiant les approches classiques. Nous proposons également des stratégies d'accélération du processus non-linéaire. Enfin un cadre orienté objet est exposé pour la mise en oeuvre de l'ensemble des méthodes proposées.
Leroudier, Julien. "Croissance rapide en solution de cristaux pour l'optique non linéaire quadratique". Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00626529.
Pełny tekst źródłaKhanagha, Vahid. "Nouvelles méthodes multi-échelles pour l'analyse non-linéaire de la parole". Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00821896.
Pełny tekst źródłaPignet, Nicolas. "Méthodes hybrides d’ordre élevé pour la mécanique des solides non-linéaire". Thesis, Paris Est, 2019. http://www.theses.fr/2019PESC1043.
Pełny tekst źródłaIn this thesis, we are interested in the devising of Hybrid High-Order (HHO) methods for nonlinear solid mechanics. HHO methods are formulated in terms of face unknowns on the mesh skeleton. Cell unknowns are also introduced for the stability and approximation properties of the method. HHO methods offer several advantages in solid mechanics: textit{(i)} primal formulation; textit{(ii)} free of volumetric locking due to incompressibility constraints; textit{(iii)} arbitrary approximation order (dollar symbol) kgeq1(dollar symbol) ; textit{(iv)} support of polyhedral meshes with possibly non-matching interfaces; and textit{(v)} attractive computational costs due to the static condensation to eliminate locally cell unknowns while keeping a compact stencil. In this thesis, primal HHO methods are devised to solve the problem of finite hyperelastic deformations and small plastic deformations. An extension to finite elastoplastic deformations is also presented within a logarithmic strain framework. Finally, a combination with Nitsche's approach allows us to impose weakly the unilateral contact and Tresca friction conditions. Optimal convergence rates of order (dollar symbol) h^{k+1}(dollar symbol) are proved in the energy-norm. All these methods have been implemented in both the open-source library DiSk++ and the open-source industrial software code_aster. Various two- and three-dimensional benchmarks are considered to validate these methods and compare them with (dollar symbol) H^1(dollar symbol)-conforming and mixed finite element methods
Vila, Michel. "Caractérisation ultrasonore de matériau à l'aide de méthodes d'acoustique non linéaire". Tours, 2004. http://www.theses.fr/2004TOUR4057.
Pełny tekst źródłaDaldoul, Mabrouk. "Contribution aux méthodes proximales et applications à la régression linéaire l1". Dijon, 1995. http://www.theses.fr/1995DIJOS042.
Pełny tekst źródłaBouafia, Mousaab. "Étude asymptotique des méthodes de points intérieurs pour la programmation linéaire". Thesis, Le Havre, 2016. http://www.theses.fr/2016LEHA0019/document.
Pełny tekst źródłaIn this research, we are interested by asymptotic study of interior point methods for linear programming. By basing itself on the works of Schrijver and Padberg, we propose two new displacement steps to accelerate the convergence of Karmarkar's algorithm and reduce its algorithmic complexity. The first step is a moderate improvement of the behaviour of this algorithm; the second represents the best fixed displacement step obtained actually. We propose two parameterized approaches of the central trajectory algorithm via a kernel function. The first function generalizes the kernel function given by Y. Q. Bai et al., the second is the first trigonometric kernel function that gives the best algorithmic complexity, obtained until now. These proposals have made new contributions of algorithmic, theoretical and numerical order
Deswarte, Raphaël. "Régression linéaire et apprentissage : contributions aux méthodes de régularisation et d’agrégation". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX047/document.
Pełny tekst źródłaThis thesis tackles the topic of linear regression, within several frameworks, mainly linked to statistical learning. The first and second chapters present the context, the results and the mathematical tools of the manuscript. In the third chapter, we provide a way of building an optimal regularization function, improving for instance, in a theoretical way, the LASSO estimator. The fourth chapter presents, in the field of online convex optimization, speed-ups for a recent and promising algorithm, MetaGrad, and shows how to transfer its guarantees from a so-called “online deterministic setting" to a “stochastic batch setting". In the fifth chapter, we introduce a new method to forecast successive intervals by aggregating predictors, without intermediate feedback nor stochastic modeling. The sixth chapter applies several aggregation methods to an oil production dataset, forecasting short-term precise values and long-term intervals
Auburtin, Christian. "Analyse linéaire et non-linéaire de structures poutres planes par éléments finis et méthodes multigrilles sur micro-ordinateur". Vandoeuvre-les-Nancy, INPL, 1990. http://www.theses.fr/1900INPL040N.
Pełny tekst źródłaHasnaoui, Marwa. "Validation et développement de méthodes pour le suivi de la croissance pré-sevrage des génisses laitières". Master's thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/36972.
Pełny tekst źródłaThe objectives of the project presented in this thesis were to validate the use of heart girth measurement in dairy calves during the pre-weaning period to estimate body weight and average daily gain, as well as to verify if other body measurements would also be effective in predicting body weight. Scale body weight and various parameters related to body size (heart girth, withers height, hip height and hip width) of 329 dairy Holstein heifers were collected from two dairy farms located in Quebec. The measurements were taken three times a week during the first three weeks of life and every two weeks until the week following weaning, which was at 76 days of life. The results of this study confirmed the feasibility of using heart girth or other body parameters to predict body weight before weaning of dairy calves. The resulting body weight prediction equation with the highest correlation and the lowest root mean squared percentage error used the heart girth. This equation showed no predictive bias compared to the main equations actually used, which showed slight bias when predicting calf body weight. However, the results suggest a better prediction of the average daily gain of pre-weaning dairy calves with the equation used locally.
Veiga, Géraldo. "Sur l'implantation des méthodes de points intérieurs pour la programmation linéaire : Texte imprimé". Paris 13, 1997. http://www.theses.fr/1997PA132010.
Pełny tekst źródłaRichou, Adrien. "Étude théorique et numérique des équations différentielles stochastiques rétrogrades". Phd thesis, Université Rennes 1, 2010. http://tel.archives-ouvertes.fr/tel-00543719.
Pełny tekst źródłaLe, Touzé David. "Méthodes spectrales pour la modélisation non-linéaire d'écoulements à surface libre instationnaires". Phd thesis, Ecole centrale de nantes - ECN, 2003. http://tel.archives-ouvertes.fr/tel-00370200.
Pełny tekst źródłaUn bilan des différentes approches spectrales employées jusqu'à présent en hydrodynamique navale est d'abord dressé, étayant le choix des techniques développées au cours de ce travail. L'étude des propriétés de ces techniques est ensuite réalisée sur le ‘noyau' de la méthode, i.e. une cuve tri-dimensionnelle de géométrie figée. En particulier, différentes techniques High-Order Spectral sont comparées entre elles et à la méthode directe, et une nouvelle variante est proposée. Des validations sur des cas de lâchers de surface libre et d'oscillations forcées de surface libre sont présentées et confrontées à diverses méthodes.
L'approche est ensuite étendue, à partir de ce ‘noyau' et au moyen de stratégies de ‘potentiel additionnel', donnant lieu au développement de divers modèles. Ainsi, des houles non-linéaires sont modélisées à l'aide de doublets tournants instationnaires spécifiquement développés. Des cas de reproduction de signaux temporels cibles à une distance, et de génération et propagation de houle irrégulière sont présentés. De plus, une caractéristique avantageuse d'une telle approche spectrale est exploitée pour proposer des modèles originaux de diffraction autour de corps. Ceux-ci allient une génération de houle par méthode spectrale à des modèles de diffraction en fluide parfait ou visqueux, formulés en changement de variable. Des exemples illustratifs de diffraction de cette houle autour de corps bi- ou tri-dimensionnels sont proposés.
Enfin, un modèle original de simulation complète, au second-ordre, du processus de génération et propagation en bassin de houle tri-dimensionnel est réalisé. Il inclut la modélisation de différents batteurs, ainsi qu'un modèle d'absorption, permettant notamment de reproduire les caractéristiques complètes du nouveau bassin de houle de l'École Centrale de Nantes. Ce modèle est validé par comparaison à une solution analytique en régime établi et ses propriétés numériques sont étudiées. L'investigation des ondes libres et leur suppression, ainsi que la caractérisation de zones utiles sont proposées à titre d'application.
Georgiou, Georges. "Sur des méthodes de commande non linéaire adaptative : aspects échantillonnés et applications". Paris 11, 1992. http://www.theses.fr/1992PA112171.
Pełny tekst źródłaShahzadeh, Fazeli Seyed Abolfazi. "Stratégies de redémarrage des méthodes itératives d'algèbre linéaire pour le calcul global". Versailles-St Quentin en Yvelines, 2005. http://www.theses.fr/2005VERS0011.
Pełny tekst źródłaL'objectif de ce travail est de contribuer à la résolution des grands problèmes de valeur propre et/ou des grands systèmes linéaires en utilisant des ressources partagées sur des réseaux plus ou moins larges. La résolution de grands systèmes d'algèbre linéaire s'effectue, à l'aide des méthodes itératives hybrides. Une méthode hybride combine plusieurs méthodes numériques différentes ou bien plusieurs copy d'une même méthode numérique paramétrées différemment afin d'accélérer la convergence de l'une de ces méthodes. L'amélioration de la vitesse de convergence et d'exécution des méthodes hybrides par des méthodologies numériques et/ou des techniques de calcul parallèle et distribué constitue l'objectif principal de cette thèse. La vitesse de convergence de ces méthodes est dépendante de l'approche utilisée lors du redémarrage du processus itératif. Nous présentons une étude sur une méthode hybride appelée Multiple Explicitly Restarted Arnoldi Method (MERAM), et nous proposons deux approches synchrones pour sa mise en oeuvre. Nous proposons également un nouvel algorithme hybride synchrone pour la méthode Implicitly Restarted Arnoldi Method. Des environnements de calcul global basés sur une approche Grid-RPC constituent un bon choix pour élaborer des programmes de résolution de problèmes sur les grilles de calcul. Un exemple typique de tels environnements est le système NetSolve. L'utilisation de ce type d'architectures nécessite la définition de nouveaux algorithmes. Une adaptation de MERAM asynchrone au système de calcul global NetSolve a été conçue. Nous avons montré que les algorithmes asynchrones de type MERAM sont très bien adaptés au calcul global. Nous avons mis en évidence un certain nombre de problèmes ouverts concernant la programmation des algorithmes hybrides en calcul global
Halard, Matthieu. "Méthodes du second ordre pour la conception optimale en élasticité non-linéaire". Paris 9, 1999. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=1999PA090029.
Pełny tekst źródłaMeziani, Rachid. "Méthodes interactives en optimisation linéaire sur micro-ordinateur : conception, réalisation et application". Paris 9, 1987. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=1987PA090030.
Pełny tekst źródłaKchouk, Bilel. "Méthodes de Chebyshev d'ordres supérieurs pour l'optimisation non linéaire, sans contrainte et différentiable". Thèse, Université de Sherbrooke, 2012. http://hdl.handle.net/11143/6682.
Pełny tekst źródłaDelignette-Muller, Marie-Laure. "Méthodes de prédiction des aptitudes de croissance des populations de micro-organismes". Lyon 1, 1995. http://www.theses.fr/1995LYO10118.
Pełny tekst źródłaTachat, Dominique. "Méthodes intérieures en programmation linéaire : élaboration et mise en œuvre de procédures de projection exacte et approchée". Paris 9, 1991. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=1991PA090009.
Pełny tekst źródłaThe thesis addresses the problem of the efficiency improvement of Karmarkar's algorithm. Different methods of both exact and approximate projections for solving the multicommodity network flow problems have been proposed. Other already existing methods have also been analyzed. Although the convergence analysis of the original algorithm has been established only in a zero optimum case, we propose several methods for more general case. Heuristical algorithm has been suggested that ensures fast convergence under the supplementary condition imposed on the step selection. Additionally, the method of Todd and Burrell has been implemented. Two approximate projection methods have been proposed to reduce the average time per iteration. The first one has been based on the observation that the angle of the objective gradient and its projection must always be acute. It has been implemented in two ways: the one exploiting the problem sparsity and the other being a variant of conjugate gradient method with a specific termination condition. Numerical results especially for the first phase are encouraging. In the second method of approximate projection, the basis of the null space of the linear operator is represented explicitly. Computational results proved that the last method outperformed other implementations of the Karmarkar's algorithm
Muller, Marie. "Evaluation ultrasonore de l'os cortical par des méthodes d'acoustique linéaire et non linéaire. Application à l'évaluation du micro endommagement osseux". Phd thesis, Université Paris-Diderot - Paris VII, 2006. http://tel.archives-ouvertes.fr/tel-00123909.
Pełny tekst źródłaLa première partie compare plusieurs techniques d'évaluation ultrasonore de l'os cortical par transmission axiale. Les propriétés ultrasonores mesurées à différentes fréquences au radius in vitro sont comparées à celles mesurées par tomographie quantitative (pQCT) ainsi qu'aux propriétés mécaniques des échantillons. Il en ressort que si les paramètres ultrasonores sont indiscutablement capables de prédire les propriétés mécaniques, leur apport sur les paramètres pQCT (actuellement mesurés en clinique) n'est envisageable que dans le cas d'une approche multi-fréquences et multi-paramètres.
La seconde partie porte sur l'étude du micro endommagement, impliqué dans la fragilisation de l'os. Nous avons fait appel à des paramètres ultrasonores nonlinéaires, qui ont fait leurs preuves dans d'autre domaines pour la mesure de l'endommagement des matériaux. Nous avons montré, en utilisant la technique de Spectroscopie Nonlinéaire Ultrasonore en Résonance, la sensibilité du paramètre ultrasonore nonlinéaire a l'endommagement progressivement accumulé dans l'os in vitro. Une relation exponentielle entre le paramètre ultrasonore nonlinéaire et l'âge des donneurs a été mise en évidence. Ceci a permis de montrer le potentiel de l'acoustique non linéaire pour la détection du micro endommagement osseux, même si des efforts doivent encore être fournis pour l'application in vivo de la méthode.
De façon plus générale, il ressort de ces travaux que le potentiel des ultrasons pour l'évaluation de la qualité osseuse réside probablement dans une approche multi-fréquences, multi-paramètres.
Muller, Marie. "Evaluation ultrasonore de l'os cortical par des méthodes d'acoustique linéaire et non linéaire : application à l'étude du micro endommagement osseux". Paris 7, 2006. http://www.theses.fr/2006PA077051.
Pełny tekst źródłaThis work is about ultrasonic characterization of cortical bone quality in vitro. In the first part, different axial transmission technique for cortical bone assessment are compared. Ultrasonic properties measured at different frequencies at the radius in vitro are compared to quantitative tomography (pQCT) properties, as well as to mechanical properties. There is no doubt that the ultrasonic parameters are capable to predict bone mechanical properties, but they may only be able to bring additional information over that brought by the pQCT parameters (currently clinically used) in a multi-parameters, multi-frequencies approach. In the second part, another parameter influencing bone quality is studied : micro damage. We used nonlinear acoustic techniques, used other fields for material's damage assessment. Using Nonlinear Ultrasound Spectroscopy techniques, we demonstrated the sensitivity of nonlinear acoustic parameters to progressively accumulated damage in bone in vitro. Interestingly, an exponential relationship between thé nonlinear acoustic parameter and the age of donors has been found. This allowed to show the potential of nonlinear acoustics for bone micro damage characterization, even though more work has to be conducted for the in vivo application of the technique. The main result of this work is the fact that the potential of Ultrasound for fracture risk assessment probably relies on a multi-frequencies multi-parameters approach
Schaal, Arnaud. "Approche hybride pour la résolution de problèmes linéaires en nombres entiers : méthodes intérieures et méta-heuristiques". Paris 9, 1997. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=1997PA090036.
Pełny tekst źródłaBellot, Jean-Christophe. "Modélisation de la chromatographie préparative non-linéaire des biomolécules". Toulouse, INSA, 1994. http://www.theses.fr/1994ISAT0034.
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