Дисертації з теми "Géométrie non-linéaire"
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Dutrieux, Yves. "Géométrie non linéaire des espaces de Banach." Paris 6, 2002. http://www.theses.fr/2002PA066118.
Peñaranda, Luis. "Géométrie algorithmique non linéaire et courbes algébriques planaires." Electronic Thesis or Diss., Nancy 2, 2010. http://www.theses.fr/2010NAN23002.
We tackle in this thesis the problem of computing the topology of plane algebraic curves. We present an algorithm that avoids special treatment of degenerate cases, based on algebraic tools such as Gröbner bases and rational univariate representations. We implemented this algorithm and showed its performance by comparing to simi- lar existing programs. We also present an output-sensitive complexity analysis of this algorithm. We then discuss the tools that are necessary for the implementation of non- linear geometric algorithms in CGAL, the reference library in the computational geom- etry community. We present an univariate algebraic kernel for CGAL, a set of functions aimed to handle curved objects defined by univariate polynomials. We validated our approach by comparing it to other similar implementations
Carbou, Gilles. "Problèmes d'analyse linéaire et non linéaire issus de la Physique et de la Géométrie." Cachan, Ecole normale supérieure, 1995. http://www.theses.fr/1995DENS0007.
Desceliers, Christophe. "Dynamique non linéaire en déplacements finis des structures tridimensionnelles viscoélastiques en rotation." Châtenay-Malabry, Ecole centrale de Paris, 2001. http://www.theses.fr/2001ECAPO720.
Lin-Shi, Xuefang. "Contribution à la modélisation et à la commande d'un vérin pneumatique de grande longueur." Lyon, INSA, 1992. http://www.theses.fr/1992ISAL0093.
The aim of the thesis is related to the modelling and the controlling of a long pneumatic cylinder. For a long pneumatic cylinder each chamber may be considered as a distributed parameter system. The first chapter presents the establishment of three distributed parameter models. The first two models are intended to simulate the dynamic behaviour of the cylinder. The first model corresponds an adiabatic hypothesis. The second model assumes an isentropic process. The third model is obtained first by the linearisation and then by the introduction of the acoustic approximation. The second chapter presents the experimental and simulated results performed on a 4,4 meters long cylinder. In the third chapter a non linear state-affine control with variable dynamic and a non linear control of the cylinder are proposed. These control laws are based on a lumped parameter model. The fourth chapter is related to the structural property study of the tank-servo-valve-cylinder-load assembly based on a bond graphs representation. The representation is deduced from the TAU method approximation applied to the linearised distributed parameter system
Alame, Ibrahim. "Application de la géométrie différentielle des groupes de Lie à la dynamique non linéaire des milieux curvilignes." Phd thesis, Ecole Nationale des Ponts et Chaussées, 1992. http://pastel.archives-ouvertes.fr/pastel-00568707.
Mardare, Sorin. "Sur quelques problèmes de géométrie différentielle liés à la théorie de l'élasticité." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2003. http://tel.archives-ouvertes.fr/tel-00270549.
Dans les deux premiers chapitres, on montre que l'inégalité de Korn sur une surface est une conséquence de l'inégalité de Korn tridimensionnelle en coordonnées curvilignes et l'on établit une inégalité de type Korn sur une surface compacte sans bord. Dans le deux derniers chapitres, on établit certains résultats de géométrie différentielle concernant les espaces riemanniens et les surfaces sous des hypothèses affablies de régularité sur les données.
Dans l'appendice, on présente quelques résultats d'analyse utilisés dans la thèse.
Catoire, Fabrice. "Equation de Schrödinger non-linéaire dans le tore plat générique et le tore de révolution." Paris 11, 2010. http://www.theses.fr/2010PA112370.
Mege, Romain, and Romain Mege. "Solutions analytiques en dynamique non-linéaire avec couplage fluide-structure." Phd thesis, Université Paris-Est, 2013. http://pastel.archives-ouvertes.fr/pastel-00971808.
Szopos, Marcela Gabriela. "Sur quelques questions de géométrie différentielle liées à la théorie des corps et des fils élastiques." Paris 6, 2005. https://tel.archives-ouvertes.fr/tel-00009754.
SZOPOS, Marcela. "Sur quelques questions de géométrie différentielle liées à la théorie des corps et des fils élastiques." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2005. http://tel.archives-ouvertes.fr/tel-00009754.
Odry, Nans. "Méthode de décomposition de domaine avec parallélisme hybride et accélération non linéaire pour la résolution de l'équation du transport Sn en géométrie non-structurée." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4058/document.
Deterministic calculation schemes are devised to numerically solve the neutron transport equation in nuclear reactors. Dealing with core-sized problems is very challenging for computers, so much that the dedicated core codes have no choice but to allow simplifying assumptions (assembly- then core-scale steps…). The PhD work aims to correct some of these ‘standard’ approximations, in order to get closer of reference calculations: thanks to important increases in calculation capacities (HPC), nowadays one can solve 3D core-sized problems, using both high mesh refinement and the transport operator. Developments were performed inside the Sn core solver Minaret, from the new CEA neutronics platform Apollo3® for fast neutrons reactors of the CFV-kind.This work focuses on a Domain Decomposition Method in space. The fundamental idea involves splitting a core-sized problem into smaller and 'independent' subproblems. Angular flux is exchanged between adjacent subdomains. In doing so, all combined subproblems converge to the global solution at the outcome of an iterative process. Domain decomposition is well-suited to massive parallelism, allowing much more ambitious computations in terms of both memory requirements and calculation time. An hybrid MPI/OpenMP parallelism is chosen to match the supercomputers architecture. A Coarse Mesh Rebalance accelration technique is added to balance the convergence penalty observed using Domain Decomposition. The potential of the new calculation scheme is demonstrated on a 3D core of the CFV-kind, using an heterogeneous description of the absorbent rods
Mege, Romain. "Solutions analytiques en dynamique non-linéaire avec couplage fluide-structure." Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST1126/document.
As the seismic loadings are increasing in accordance to the recent regulations regarding Earthquake design, the use of sliding devices in structures is becoming more common. These devices limitate the internal forces by creating a rigid body sliding. It is then necessary to estimate the global displacement of the structure, especially concerning structures that are immersed in a reservoir. In this case, the displacement must be well estimated in order to prevent impacts between the sliding structure and the boundaries of the reservoir. We can find such structures in : bridges, costal structures in brick and masonry, or in the nuclear industry with the underwater fuel storage racks, ...The governing equations for the behaviour of these structures are non linear and must be solved using time-consuming computer simulations which are not fit for a stochastic study. Our method consists in, firstly, evaluating analytically the added masses of the fluid-structure interaction, secondly, a semi-analytical solving of the governing equations including the updating of the dimensions of the fluid layers surrounding the sliding structure. The results of this new method are in accordance with the numerical simulations and can be obtained in a short time (1 or 2 seconds) which offers the possibility to make a stochastic analysis of the non linear behaviour
Laurain, Paul. "Comportement asymptotique des surfaces à courbure moyenne constante." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2010. http://tel.archives-ouvertes.fr/tel-00559640.
Dervaux, Julien. "Morphogénèse et élasticité en géométrie mince." Phd thesis, Université Paris-Diderot - Paris VII, 2010. http://tel.archives-ouvertes.fr/tel-00544143.
MOUMAS, Valérie. "Application des méthodes intégrales pour l'évaluation de la performance des puits horizontaux dans un réservoir stratifié à géométrie quelconque." Phd thesis, Université de Technologie de Compiègne, 2003. http://tel.archives-ouvertes.fr/tel-00004274.
Moumas, Valérie. "Application des méthodes intégrales pour l'évaluation de la performance des puits horizontaux dans un réservoir stratifié à géométrie quelconque." Compiègne, 2003. http://www.theses.fr/2003COMP1465.
Boundary integral methods make it possible to overcome the scale difference between the size of the reservoir (several kilometers) and the radius of the weIl (less than 15 cm). They have recently been used in petroleum engineering, but they were limited to 2D problems, and the weIl was modelled like a source term. Here we propose a new boundary integral method to evaluate weIl performance in a 3D stratified reservoir with arbitrary geometry. The flow in the weIl is modelled using one of two boundary conditions, the first one linear, the second one non-linear and non-local. We have proved that both models are well-posed, and we have developed a new boundary integr al formulation to treat the linear mode!. Boundary integral equations have been discretized by a Galerkin method, and integrals on the weIl have been reduced to ID integrals, thanks to the scale difference. WeIl productivity index can be calculated by our new method with a precision of 1%
Tripathi, Bharat. "Discontinuous Galerkin Method for Propagation of Acoustical Shock Waves in Complex Geometry." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066344/document.
A new numerical solver for the propagation of acoustical shock waves in complex geometry has been developed. This is done starting from the discontinuous Galerkin method. This method is based on unstructured mesh (triangular elements here), and so, naturally it is well-adapted for complex geometries. Nevertheless, the discretization induces Gibbs oscillations. To manage this problem, we choose to introduce some artificial viscosity only in the vicinity of the shocks. This necessitates the development of three original tools. First of all, a new shock sensor for unstructured mesh sensitive to acoustical shock waves has been designed. It senses where the local artificial viscosity has to be introduced thanks to a reformulation of a new element centred smooth artificial viscosity term in the equations. Finally, the amount of viscosity is computed by the introduction of an original notion of gradient factor linked to the steepening of the waveform. The numerical solver has been used to investigate two different physical situations. The first one is the nonlinear reflection of acoustical shock waves on rigid surfaces. Different regimes of reflection have been observed ranging from the linear Snell Descartes reflection to the weak von Neumann case. The second configuration deals with the focusing of shock waves produced by high intensity transducers (like in HIFU). Special attention has been given to the careful computation of intensity and to the interaction between the shock waves and obstacles in the region of the focus
Ge, Yuxin. "Sur quelques équations aux dérivées partielles nonlinéaires provenant de la géométrie." Cachan, Ecole normale supérieure, 1997. http://www.theses.fr/1997DENS0029.
Gilardet, Mathieu. "Étude d’algorithmes de restauration d’images sismiques par optimisation de forme non linéaire et application à la reconstruction sédimentaire." Thesis, Pau, 2013. http://www.theses.fr/2013PAUU3040/document.
We present a new method for seismic image restoration. When observed, a seismic image is the result of an initial deposit system that has been transformed by a set of successive geological deformations (folding, fault slip, etc) that occurred over a large period of time. The goal of seismic restoration consists in inverting the deformations to provide a resulting image that depicts the geological deposit system as it was in a previous state. With our contribution, providing a tool that quickly generates restored images helps the geophysicists to recognize geological features that may be too strongly altered in the observed image. The proposed approach is based on a minimization process that expresses geological deformations in terms of geometrical constraints. We use a quickly-converging Gauss-Newton approach to solve the system. We provide results to illustrate the seismic image restoration process on real data and present how the restored version can be used in a geological interpretation framework
Arsigny, Vincent. "Traitement de données dans les groupes de Lie : une approche algébrique. Application au recalage non-linéaire et à l'imagerie du tenseur de diffusion." Phd thesis, Ecole Polytechnique X, 2006. http://tel.archives-ouvertes.fr/tel-00121162.
Huangfu, Yigeng. "La recherche de systèmes nonlinéaires de contrôle de mode glissant à Ordre Supérieur et ses applications pour la MSAP." Belfort-Montbéliard, 2010. http://tel.archives-ouvertes.fr/tel-00608229/fr/.
Nonlinear system control has been widely concern of the research. At present, the nonlinear system decoupling control and static feedback linearization that based on the theory of differential geometry brought the research getting rid of limitation for local linearization and small scale motion. However, differential geometry control must depend on precise mathematical model. As a matter of fact, the control system usually is with parameters uncertainties and output disturbance. In this thesis, nonlinear system of control theory has been studied deeply. Considering sliding mode variable structure control with good robust, which was not sensitive for parameters perturbation and external disturbance, the combination idea of nonlinear system and sliding mode controls was obtained by reference to the large number of documents. Thus, it not only can improve system robustness but solve the difficulties problem of nonlinear sliding mode surface structure. As known to all, traditional sliding mode had a defect that is famous chattering phenomenon. A plenty of research papers focus on elimination/avoidance chattering by using different methods. By comparing, the document is concerned with novel design method for high order sliding mode control, which can eliminate chattering fundamentally. Especially, the approach and realization of nonlinear system high order sliding mode control is presented in this paper. High order sliding mode technique is the latest study. This thesis from the theory analysis to the simulation and experiment deeply study high order sliding mode control principle and its applications. By comparison, the second order sliding mode control law (also known as dynamic sliding mode control, DSM) may be effective to eliminate the chattering phenomenon. But it is still unable to shake off the requirement of system relative degree. Therefore, arbitrary order sliding mode controller is employed, whose relative degree can equal any values instead of one. The robot car model adopted high order sliding mode is taken as an example. The simulation results show that the tracking control is effective. In the control systems design, it is very often to differentiate the variables. Through the derivation of sliding mode, the expression of sliding mode differential value is obtained. The simulation results certificate sliding mode differentiator with robustness and precision. At the same time, the differentiator for arbitrary sliding mode is given to avoiding conventional complex numerical calculation. It not only remains the precision of variables differential value, but also obtains the robustness. A direct application is simplification for high order sliding mode controller. Due to its inherent advantages, the permanent magnet synchronous motor (PMSM) deserves attention and is the most used drive in machine tool servos and modern speed control applications. For improving performance, this paper will applied nonlinear high order sliding mode research achievement to MIMO permanent magnet synchronous motor. It changes the coupling nonlinear PMSM to single input single output (SISO) linear subsystem control problem instead of near equilibrium point linearization. Thereby, the problem of nonlinear and coupling for PMSM has been solved. In addition, Uncertainty nonlinear robust control system has been well-received study of attention. Because the robust control theory is essentially at the expense of certain performance. This kind of robust control strategy often limits bandwidth of closed loop, so that system tracking performance and robustness will be decreased. So, sliding mode control is an effective approach for improving system robust. This thesis first proposed a robust high order sliding mode controller for PMSM. The system has good position servo tracking precision in spite of parameters uncertainties and external torque disturbance. On this basis, According to the principle of high order sliding mode, as well as differentiator, the state variables of PMSM are identified online firstly and successfully. The results of simulation indicate observe value has high precision when sliding mode variable and its differentials are convergent into zero. The same theory is used in external unknown torque disturbance estimation online for PMSM. As if, load torque will no longer be unknown disturbance. System performance can be improved greatly. It establishes theoretical foundation for the future applications. At the end of paper, using advanced half-physical platform controller dSPACE to drive a PMSM, hardware experiment implement is structured completely. The experiment results illustrate that PMSM adopting precious feedback linearization decoupling and high order sliding mode controller can realize system servo tracking control with good dynamic and steady character
Berard, Vincent. "Les applications conforme-harmoniques." Phd thesis, Université de Strasbourg, 2010. http://tel.archives-ouvertes.fr/tel-00468343.
Junca, Stéphane. "Optique géométrique non linéaire, chocs forts, relaxation." Nice, 1995. http://www.theses.fr/1995NICE4877.
Boulenger, Thomas. "Explosion des solutions de Schrödinger de masse critique sur une variété riemannienne." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00922988.
Guenfoud, Mohammed. "Deux éléments triangulaires nouveaux pour l'analyse linéaire et non linéaire géométrique des coques." Lyon, INSA, 1990. http://www.theses.fr/1990ISAL0088.
[The construction of a simple and effective numerical model for curved structures is an important and continually up-dated subject. The work developed in this domain is related to two principal difficulties. * The geometrical hypothesis adopted in the shell theory (shallows shell or deep shell theory). * The kinematic hypothesis adopted in the strain-displacement relations. The elements developed in this paper are based on the curvilinear shell theory proposed by PARK and on the HENCKY - MINDLIN's kinematic hypothesis. Generally, two problems are encountered during the modelling of the co curved structures. The first problem is the geometrical representation of the structure, solved by realizing a simple geometrical approximation. The second is the membrane and transverse shear locking phenomenon. The most generally used solutions for treating the locking phenomenon are the method of reduced integration and the mode decomposition technique. However, these solutions remain curative and lead many problems either with their limited field or of a numerical nature. These difficulties led to a new. Method based on the approach of PARK which constitutes a preventive solution: indeed this approach is based in the avoidance of these problems before they appear. Two shell elements based on this approach are formulated. The first element is a three nodes linear triangular element and the second one is a six nodes quadratic triangular element. ]
Ghazlan, Ghassan. "Modélisation non linéaire matérielle et géométrique des coques minces." Clermont-Ferrand 2, 1991. http://www.theses.fr/1991CLF21382.
Harrivel, Dikanaina. "Théorie des champs : approche multisymplectique de la quantification, théorie perturbative et application." Phd thesis, Université d'Angers, 2005. http://tel.archives-ouvertes.fr/tel-00011761.
Nous nous interessons tout d'abord à l'équation linéaire et nous proposons une description multisymplectique de la quantification canonique par le biais d'une representation des symétries, de la quantification par deformation et enfin nous introduisons la notion de quatification par déformation multisymplectique.
Ensuite nous traitons le champ en interaction. Nous construisons dans un premier temps des observables sous la forme de séries sur les arbres plans puis nous montrons comment elles peuvent être reliées aux séries de Butcher. Enfin nous voyons comment appliquer nos résultats à la théorie du contrôle.
Usnich, Alexandr. "Sur le groupe de Cremona et ses sous-groupes." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2008. http://tel.archives-ouvertes.fr/tel-00812808.
Tiar, Mohamed Amine. "Éléments finis spéciaux pour l’analyse linéaire et non-linéaire géométrique des structures composites à renforts fibreux." Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2345/document.
Numerical modeling of composite materials and structures with complex geometry of fiber reinforcement, such as stitched composites, constitutes a major research axis in order to correctly predict their mechanical behavior. Within this context, this study focuses on the development of new linear and nonlinear specific finite elements based on a multiscale numerical approach, called the Projected Fiber Approach (PFA). This numerical approach has the advantage of taking into account the presence of fi bers, long or short and distributed randomly or specifically, within a matrix space without discretizing them. Consequently, the obtained system of equations size is equivalent to that without reinforcement (matrix), which considerably reduces the computational cost. To analyze the linear and geometrically nonlinear behaviors of composite structures, two membrane finite elements, named PFT3 and PFQ4, and a 3D solid finite element, named PFH8, were developed and implemented into the commercial finite element code ABAQUS via the user element subroutine (UEL). Several numerical linear and nonlinear tests are considered to assess the accuracy and efficiency of the proposed composite finite elements, and the obtained results are globally in good agreement with the reference solutions. Moreover, the major interest of the PFA approach is particularly emphasized by studying two 3D complex reinforced composite structures: a stitched sandwich plate and a hollow core sandwich plate reinforced by "8" shape fibers
Gao, Tian. "Pneumatic gaussian morphing : Geometry and mechanics of inflatable architected plates and shells." Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS546.
Cartographers have early realized that it is impossible to draw a flat map of the Earth without distorting continents. Carl Gauss later generalized this geometrical constrain in his seminal Theorema Egregium. Can we invert the configuration and obtain 3D shapes by changing local distances (ie, metrics) in an initially flat plate? This strategy is widely used in Nature: leaves or petals may develop into very complex shapes through differential growth. Nevertheless, imposing metrics is not enough to define the geometry of a surface and controlling local bending is necessary to select between different isometric shapes. In this thesis, we address shape morphing through three different strategies. From an engineering point of view, metric changes can be imposed by inflating channels embedded in a polymeric plate or in between to pieces of fabric as it induces extension or contraction along director lines. We first show how a zigzag meso-structure brings an extra degree of freedom in the design space to program complex 3D structures. A second chapter is dedicated to the control of local bending (in addition to metrics) by designing channels of non-symmetric cross-section. In addition to bending ribbons or self-folding origami structures, different isometric shapes can be designed with this versatile technique. In a third chapter we finally show how bending the facets in curved fold origami can be harvested to deploy efficiently 3D structures
Bouhineau, Denis. "Construction automatique de figures géometriques et programmation logique avec contraintes." Phd thesis, Université Joseph Fourier (Grenoble), 1997. http://tel.archives-ouvertes.fr/tel-00004922.
Kerour, Brahim. "Recherche des zones d'écoulement dans un milieu granulaire ensilé et modélisation des actions exercées sur les parois déformables du silo." Rennes, INSA, 2001. http://www.theses.fr/2001ISAR0007.
Chahrour, Ibrahim. "Contribution a l'analyse non-linéaire matérielle et géométrique des coques en béton armé." Lyon, INSA, 1991. http://www.theses.fr/1991ISAL0068.
The development of a simple and efficient numerical madel describing correctly the behaviour of reinforced concrete structures is of reat interest, especially when dealing with curved structures. The aim of this study is to contribute to the physically and geometrically nonlinear computer analysis of eneral reinforced concrete shells subjected to time invariant loads up to failure. The first part of this study presents a survey of preceding works in the field. The different approches are discussed and our choices are justified. The second part is devoted to the development of an efficient shell element. It results from the superposition of a plate element based on the discretization of the MIDLIN theory and the CST element. The initial curvature is incorporated using the MARGUERRE shallow shell theory. The effect of coupling membrane and bending creates the membrane locking phenomenon which is treated by the mode decomposition technique. In the third part, we present the constitutive madel of concrete which is based on the elàstoplastic theory and describes correctly the dissymmetry of its behaviour in tension and compression. This madel is incorporated in a layered approache. The range of applicability of the modelis finally proven by several theorical and experimental results
Djeghaba, Kamel. "Contribution à l'analyse non linéaire géométrique des coques minces en théorie de Marguerre." Lyon, INSA, 1990. http://www.theses.fr/1990ISAL0043.
[The numerical representation using finite element of geometrically non linear behaviour of curved structures is of considerable interest. The objective of this work is to give a contribution to geometrically non linear analysis by the construction of an arch and a shell elements using MARGUERRE's theory. The first part concerns the choice :of suitable shell theory and the MARGUERRE's one present more advantages in simplicity and efficiency than those classical. The effects of coupling between membrane and pending creates the membrane locking phenomenon which is treated by the mode decomposition technique. The description of motion is made in A. U. L. D. (Approximate Updated Lagrangian Description). Its association with MARGUERRE 's theory referenced in a corotationnal axes leads us to the description that we call Co rotational Lagrangian Description in MARGUERRE's theory and note C. L. D. M. . The second and the third parts concerns the construction of the two elements using C. L. D. M. And A. U. L. D. And the presentation of NEWTON-RAPHSON algorithms for solving the non linear process. Many tests and examples are presented in the last part to demonstrate the accuracy and efficiency of the C. L. D. M. In solving geometrically non linear problems specially in the reduction of the computing time. ]
Bouhineau, Denis. "Construction automatique de figures géometriques et programmation logique avec contraintes." Phd thesis, Grenoble 1, 1997. https://theses.hal.science/tel-00004922.
Dellinger, Marie. "Etude asymptotique et multiplicité pour l'équation de Sobolev Poincaré." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2007. http://tel.archives-ouvertes.fr/tel-00261595.
on considère une edp elliptique non linéaire à exposant critique particulière : l'équation de Sobolev Poincaré. D'une part, nous décrivons le comportement asymptotique d'une suite de solutions de cette équation grâce à une analyse fine de phénomènes de concentration. D'autre part, en imposant des invariances par des groupes d'isométries, nous montrons des résultats de multiplicité de solutions pour cette équation. Notre méthode permet aussi d'obtenir des multiplicités de solutions pour des équations plus classiques provenant du problème deYamabe et de Nirenberg, ainsi que
pour des équations à exposants sur critiques. Notre travail est intimement lié à la description des meilleures constantes dans des inégalités fonctionnelles de Sobolev associées aux équations.
Mehmood, Adeel. "Modeling, simulation and robust control of an electro-pneumatic actuator for a variable geometry turbocharger." Phd thesis, Université de Technologie de Belfort-Montbeliard, 2012. http://tel.archives-ouvertes.fr/tel-00827445.
Thomann, Laurent. "Instabilité des équations de Schrödinger." Phd thesis, Université Paris Sud - Paris XI, 2007. http://tel.archives-ouvertes.fr/tel-00265284.
Dans la première partie on met en évidence un mécanisme de décohérence de phase pour l'équation (semi-classique) de Gross-Pitaevski en dimension 3. Ce phénomène géométrique est dû à la présence du potentiel harmonique, qui permet de construire -via une méthode de minimisation- des solutions stationnaires se concentrant sur des cercles de R^{3}.
Dans la deuxième partie, on obtient un résultat d'instabilité géométrique pour NLS cubique posée sur une surface riemannienne possédant une géodésique périodique, stable et non-dégénérée. Avec une méthode WKB, on construit des quasimodes non-linéaires, qui permettent d'obtenir des solutions approchées pour des temps pour lesquels l'instabilité se produit. On généralise ainsi des travaux de Burq-Gérard-Tzvetkov pour la sphère.
Enfin, dans la dernière partie on considère des équations sur-critiques sur une variété de dimension d. Grâce à une optique géométrique non-linéaire dans un cadre analytique on peut montrer un mécanisme de perte de dérivées dans les espaces de Sobolev, et une instabilité dans l'espace d'énergie.
Caullery, Florian. "Polynomes sur les corps finis pour la cryptographie." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4013/document.
Functions from F_q to itself are interesting objects arising in various domains such as cryptography, coding theory, finite geometry or algebraic geometry. It is well known that these functions admit a univariate polynomial representation. There exists many interesting classes of such polynomials with plenty of applications in pure or applied maths. We are interested in three of them: Almost Perfect Nonlinear (APN) polynomials, Planar (PN) polynomials and o-polynomials. APN polynomials are mostly used in cryptography to provide S-boxes with the best resistance to differential cryptanalysis and in coding theory to construct double error-correcting codes. PN polynomials and o-polynomials first appeared in finite geometry. They give rise respectively to projective planes and ovals in P^2(F_q). Also, their field of applications was recently extended to symmetric cryptography and error-correcting codes.A complete classification of APN, PN and o-polynomials is an interesting open problem that has been widely studied by many authors. A first approach toward the classification was to consider only power functions and the studies were recently extended to polynomial functions.One way to face the problem of the classification is to consider the polynomials that are APN, PN or o-polynomials over infinitely many extensions of F_q, namely, the exceptional APN, PN or o-polynomials.We improve the partial classification of exceptional APN and PN polynomials and give a full classification of exceptional o-polynomials. The proof technique is based on the Lang-Weil bound for the number of rational points in algebraic varieties together with elementary methods
Mahé, Michel. "Analyse non linéaire géométrique des coques par éléments finis isoparamétriques dégénérés avec intégration explicite dans l'épaisseur." Toulouse, ENSAE, 1991. http://www.theses.fr/1991ESAE0013.
Barrailh, Laurioux Karen. "Étude mathématique et numérique de modèles de propagation issus de l'optique non linéaire." Bordeaux 1, 2002. http://www.theses.fr/2002BOR12544.
Aouameur-Mesbah, Amel. "Analyse non-linéaire matérielle et géométrique des structures coques en béton armé sous chargements statiques et dynamiques." Phd thesis, Ecole Nationale des Ponts et Chaussées, 1998. http://tel.archives-ouvertes.fr/tel-00529774.
Aouameur, Amel. "Analyse non-linéaire matérielle et géométrique des structures coques en béton arme sous chargements statiques et dynamiques." Marne-la-vallée, ENPC, 1998. https://pastel.archives-ouvertes.fr/tel-00529774.
Brunswic, Léo. "Surfaces de Cauchy polyédrales des espaces temps plats singuliers." Thesis, Avignon, 2017. http://www.theses.fr/2017AVIG0420/document.
The study of singular flat spacetimes with polyhedral Cauchy-surfaces is motivated by the quantum gravity toy model role they play in the seminal work of Deser, Jackiw and 'T Hooft. This thesis study parametrisations of classes of singular flat spacetimes : Cauchy-compact maximal flat spacetimes with massive and BTZ-like singularities. Two parametrisations are constructed. The first is based on an extension of Mess theorem to flat spacetimes with BTZ and Penner-Epstein convex hull construction. The second is based on a generalisation of Alexandrov polyhedron theorem to radiant Cauchy-compact flat spacetimes with massive and BTZ-like singularities. This work also initiate a wider theoretical background that encompass singular spacetimes
Dagrau, Franck. "Simulation de la propagation du bang sonique : de la CFD à l'acoustique non linéaire." Paris 6, 2009. http://www.theses.fr/2009PA066628.
Shakourzadeh, Bolouri Hossein. "Modélisation des structures-poutres tridimensionnelles à parois minces et simulation du comportement non linéaire géométrique et élasto-plastique." Compiègne, 1994. http://www.theses.fr/1994COMPD773.
Robert, Florent. "Contribution à l'analyse non linéaire géométrique et matérielle des ossatures spatiales en Génie Civil : application aux ouvrages d'art." Lyon, INSA, 1999. http://theses.insa-lyon.fr/publication/1999ISAL0032/these.pdf.
In the field of civil engineering, the current trend to design structures more and more slender and the need to reduce the quantities of material, lead designers to make nonlinear calculations taking into account of the nonlinearities of the System. In the field of engineering structures, considering both material and geometrical nonlinearities is essential, therefrom the necessity to have computer tools fitting the profession and solving that problem. We propose a space convected coordinates based formulation consisting in breaking up the movement of a particle into a large rigid body movement and a small movement inducing strains. Large displacements and large rotations are taken into account for tridimensional beam éléments, whereas the material nonlinearity is based on the hypothesis of small strains. We can modelize space frames made of métal, of reinforced concrète or prestressed concrète. Delayed effects, that are concrète shrinkage and creep and prestressed concrète steel relaxation, are integrated in the général resolution scheme. In order to simulate the engineering structures construction and to study their statics, we consider large displacements for articulations, and we develop a spécifie beam élément that simulâtes correctly the behaviour of weighty cables, even though when not tensed. From the initial stress matrix, we develop the linear instability calculation. We propose the possible extension of our resolution scheme from static loads to dynamic ones. We validate our approach by comparing the results of our calculations tô the expérimental results or the theoretical solution of représentative tests. At last, an example of use of the programme on a real project is shown : the simulation of the replacement of the suspension System of the Tancarville Bridge
Van, Dootingh Marjoleine. "Polymérisation radicalaire : commande géométrique et observation d'état à l'aide d'outils non linéaires." Rouen, 1992. http://www.theses.fr/1992ROUES022.
Biscara, Claudine. "Exécuter des dessins géométriques : approche développementale." Montpellier 3, 2006. http://www.theses.fr/2006MON30061.
This study deals with execution of drawings composed of embedded geometric shapes. Previous studies conducted by Baldy, Chatillon and Cadopi (1993) provided evidence for the existence of two executions : centripetal (outside to inside direction) and centrifugal (inside to outside direction). In these studies, it also appeared that, most of the time, the centripetal execution was produced. Our research focuses on its stability. Two series of experiments were carried out with children and adults. In the first one, participants copy several drawings. In the second one, the procedure we used is based on the theory of non linear dynamic systems. Indeed, participants have to reproduce a drawing by completing a continuum of circles which diameter gradually varies. The main results were the following. First, we confirm the effet of pattern structure on the execution ordre (Baldy, Chatillon & Magnan, 2001 ; van Sommers, 1984 ; Marot & Vinter, 2003). Second, we observe that the execution is influenced by previous execution(s), especially for young children. The centrifugal execution appears as stable as the centripetal execution since it resists to contextual contraints. This research underlines the relevance of using a dynamic approach to account of both within-individual variability and the cognitive development