Дисертації з теми "Lagrange optimisation"
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Giri, Jason University of Ballarat. "Non-linear analogues of Lagrange functions in constrained optimization." University of Ballarat, 2005. http://archimedes.ballarat.edu.au:8080/vital/access/HandleResolver/1959.17/12782.
Повний текст джерелаDoctor of Philosophy
Giri, Jason. "Non-linear analogues of Lagrange functions in constrained optimization." University of Ballarat, 2005. http://archimedes.ballarat.edu.au:8080/vital/access/HandleResolver/1959.17/14618.
Повний текст джерелаDoctor of Philosophy
Monokrousos, Antonios. "Optimisation and control of boundary layer flows." Licentiate thesis, Stockholm : Skolan för teknikvetenskap, Kungliga Tekniska högskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10652.
Повний текст джерелаHemazro, Tekogan Dzigbodi. "Le problème de répartition des clientèles scolaires." Sherbrooke : Université de Sherbrooke, 1998.
Знайти повний текст джерелаSaissi, Fatima Ezzarha. "Optimisation à deux niveaux : Résultats d'existence, dualité et conditions d'optimalité." Thesis, Limoges, 2017. http://www.theses.fr/2017LIMO0030.
Повний текст джерелаSince its introduction, the class of tao-level programming problems has attracted increasing interest. Indeed, because of its applications in a multitude of concrete problems (management problems, economic planning, chemistry, environmental sciences,...), several researchers have been interested in the study of such class of problems. This thesis deals with the study of some classes of two-level optimization problems, namely, strong two-level problems, strong-weak two-level problems and semi-vectorial two-level problems. In the first chapter, we have recalled some definitions and results related to topology and convex analysis that we have used in our study. In the second chapter, we have discussed some theoretical and algorithmic results established in the literature for solving some classes of two-level optimization problems. The third chapter deals with strong-weak Stackelberg problems. As it is well-known, such a class of problems presents difficulties in its study concerning the existence of solutions. So that, for a strong-weak two-level optimization problem, we have first given a regularization. Then, via this regularization and under appropriate assumptions we have shown the existence of solutions to such a problem. This result generalizes the one given in the literature for weak Stackelberg problems. In the fourth chapter, we have given a duality approach for a strong two-level programming problem (S). The duality approach is based on the use of a regularization and the Fenchel-Lagrange duality. Then, via this approach, we have given necessary optimality conditions for (S). Finally, sufficient optimality conditions are given for the initial problem (S). An application to a two-level resource allocation problem is given. In the fifth chapter, we have considered a semivectorial two-level programming problem (SVBL) where the upper and lower levels are vectorial and scalar respectively. For such a problem, we have given a duality approach based on the use of a regularization, a scalarization and the Fenchel-Lagrange duality. Then, via this approach we have established necessary optimality conditions for (SVBL). Finally, we have given sufficient optimality conditions without using the duality approach
Monokrousos, Antonios. "Optimisation and control of shear flows." Doctoral thesis, KTH, Stabilitet, Transition, Kontroll, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-33771.
Повний текст джерелаQC 20110518
Grigoleit, Mark Ted. "Optimisation of large scale network problems." Thesis, Curtin University, 2008. http://hdl.handle.net/20.500.11937/1405.
Повний текст джерелаGrigoleit, Mark Ted. "Optimisation of large scale network problems." Curtin University of Technology, Department of Mathematics and Statistics, 2008. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=115092.
Повний текст джерелаWe then use this information to constrain the network along a bisecting meridian. The combination of Lagrange Relaxation (LR) and a heuristic for filtering along the meridian provide an aggressive method for finding near-optimal solutions in a short time. Two network problems are studied in this work. The first is a Submarine Transit Path problem in which the transit field contains four sonar detectors at known locations, each with the same detection profile. The side constraint is the total transit time, with the submarine capable of 2 speeds. For the single-speed case, the initial LR duality gap may be as high as 30%. The first hybrid method uses a single centre meridian to constrain the network based on the unused time resource, and is able to produce solutions that are generally within 1% of optimal and always below 3%. Using the computation time for the initial Lagrange Relaxation as a baseline, the average computation time for the first hybrid method is about 30% to 50% higher, and the worst case CPU times are 2 to 4 times higher. The second problem is a random valued network from the literature. Edge costs, times, and lengths are uniform, randomly generated integers in a given range. Since the values given in the literature problems do not yield problems with a high duality gap, the values are varied and from a population of approximately 100,000 problems only the worst 200 from each set are chosen for study. These problems have an initial LR duality gap as high as 40%. A second hybrid method is developed, using values for the unused time resource and the lower bound values computed by Dijkstra’s algorithm as part of the LR method. The computed values are then used to position multiple constraining meridians in order to allow LR to find better solutions.
This second hybrid method is able to produce solutions that are generally within 0.1% of optimal, with computation times that are on average 2 times the initial Lagrange Relaxation time, and in the worst case only about 5 times higher. The best method for solving the Constrained Shortest Path Problem reported in the literature thus far is the LRE-A method of Carlyle et al. (2007), which uses Lagrange Relaxation for preprocessing followed by a bounded search using aggregate constraints. We replace Lagrange Relaxation with the second hybrid method and show that optimal solutions are produced for both network problems with computation times that are between one and two orders of magnitude faster than LRE-A. In addition, these hybrid methods combined with the bounded search are up to 2 orders of magnitude faster than the commercial CPlex package using a straightforward MILP formulation of the problem. Finally, the second hybrid method is used as a preprocessing step on both network problems, prior to running CPlex. This preprocessing reduces the network size sufficiently to allow CPlex to solve all cases to optimality up to 3 orders of magnitude faster than without this preprocessing, and up to an order of magnitude faster than using Lagrange Relaxation for preprocessing. Chapter 1 provides a review of the thesis and some terminology used. Chapter 2 reviews previous approaches to the CSPP, in particular the two current best methods. Chapter 3 applies Lagrange Relaxation to the Submarine Transit Path problem with 2 speeds, to provide a baseline for comparison. The problem is reduced to a single speed, which demonstrates the large duality gap problem possible with Lagrange Relaxation, and the first hybrid method is introduced.
Chapter 4 examines a grid network problem using randomly generated edge costs and weights, and introduces the second hybrid method. Chapter 5 then applies the second hybrid method to both network problems as a preprocessing step, using both CPlex and a bounded search method from the literature to solve to optimality. The conclusion of this thesis and directions for future work are discussed in Chapter 6.
Stoll, Benoît. "Optimisation de Fonctions de Contraste en Séparation de Sources." Toulon, 2000. http://www.theses.fr/2000TOUL0001.
Повний текст джерелаBlind Source Separation aim to recover a set of M independent signals called sources from the observation of N mixtures. Several Source Separation methods exist, most of them are based on Higher Order Statistics. Those methods exploit the source independence hypothesis. Among them we consider the case of the source separation based on contrast function optimization in a spatial linear mixture case. We first propose two contrast families including as a particular case some existing contrasts. Then we determine the optimal solution in a two sources case for this couple of contrast families, thus proposing two algorithms which constitute two classic algorithm generalizations. Then, we study constrained contrast optimization in order to propose algorithms which don't need, as before, data pre-whitening. Two direct constrained optimization method families are considered : the dual methods and the direct methods. Thus we can develop algorithms using Lagrangian concept, penalization concept and a concept of projecting onto the constraint. Com¬puter simulations illustrate the behaviour of the algorithms
Lambert, Pierre-Alain. "Optimisation de formes en aérodynamique : application à la conception des nacelles de moteurs civils." Châtenay-Malabry, Ecole centrale de Paris, 1995. http://www.theses.fr/1995ECAP0420.
Повний текст джерелаIsnard, François. "Génération des équations du mouvement de systèmes polyarticulés avec prise en compte des rigidités par des multiplicateurs de Lagrange." Poitiers, 1997. http://www.theses.fr/1997POIT2344.
Повний текст джерелаVirin, Teddy. "Modélisation, optimisation et contrôle d'un processus d'épandage pour les applications agricoles." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2007. http://tel.archives-ouvertes.fr/tel-00717799.
Повний текст джерелаBarbet, Luc. "Etude de sensibilité différentielle dans un problème d'optimisation paramétrique avec contraintes en dimension infinie." Poitiers, 1992. http://www.theses.fr/1992POIT2263.
Повний текст джерелаHayouni, Mohammed. "Existence et régularité pour des problèmes d'optimisation de formes." Nancy 1, 1997. http://www.theses.fr/1997NAN10089.
Повний текст джерелаThe first part of this work deals with the existence and the Lipschitz regularity of the state function in a shape optimization problem. This problem consists in fin ding an open subset of R[exponent]N with a prescribed measure, which minimizes the energy associated to the Dirichlet problem on such sets. We start by using a variational approach to get the existence result. Then, we introduce an approximated variational problem and prove that its solutions are regular since the EulerLagrange equation is a semi-linear partial differential equation. Provided that those solutions do not change their signs, we show that they are uniformly Lipschitz regular and therefore, converges to a Lipschitz solution to the initial variational problem. Moreover, the set where this state function does not vanish is a solution to the considered shape optimisation problem. The second part is devoted to the study, in 2 and 3 dimensions, of the continuity, with respect to the variations of a bounded domain (in Hausdorff sense), of the solutions of the biharmonic problem with homogenous Dirichlet boundary conditions. We first give a necessary and sufficient condition on the domaine under which the continuity holds. Then we bring out some simple and sufficient conditions on the boundary of the domain. Pinally, we give an explicit example of homogenization of the gradient in 2 dimension al case
Lopez, Lopez Alberto. "Optimisation de forme des structures minces." Compiègne, 1989. http://www.theses.fr/1989COMPD187.
Повний текст джерелаBellaassali, Said. "Contributions à l'optimisation multicritère." Dijon, 2003. https://tel.archives-ouvertes.fr/tel-00004337v2.
Повний текст джерелаThe aim of this work is to study multiobjective optimization problems with or without dynamics and the generalized Bolza problem and its applications. After having pointed out some concepts of nonsmooth analysis, we begin the first part of this thesis with the existence of Lagrange multipliers for multiobjective optimization problems in infinite dimension with a general preference. We introduce the regularity of preference and use calmness qualification condition we establish the existence of Karush-Kuhn-Tucker multipliers. This allows us to obtain Fritz-John multipliers in terms of the approximate subdifferential by Ioffe. Then we derive similar results when the preference is defined by a convex cone or by an utility function. The second part deals with generalized Bolza problem. We establish necessary optimality conditions in terms of limiting Fréchet subdifferential without convexity assumptions. This result enables us to obtain the results by Vinter-Zheng and Ioffe-Rockafellar and to establish maximum principle including a new Euler-Lagrange inclusion. We apply this last one to isoperimetric problems, to the general Ramsey model of economic growth and to a chemical engineering problem. Using the notion of preference of the first part and the results of the second part we establish in the third part necessary optimality conditions and Hamiltonian conditions to multiobjective dynamic optimization. We give similar results in the case of a preference defined by a convex cone or an utility function
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.
Повний текст джерелаHannachi, Manel. "Formulation d'éléments finis volumiques adaptés à l'analyse kinéaire et non linéaire et à l'optimisation de coques isotropes et composites." Compiègne, 2007. http://www.theses.fr/2007COMP1704.
Повний текст джерелаWe present in this study two new three-dimensional solid-shell finite elements, using only displacements degrees of freedom (3 per node), for linear and nonlinear analysis of isotropic and composite shells. The first part of this thesis deals with to the presentation of the finite element formulation, starting from hexahedron element with 8 nodes SCH8 and prism with 6 nodes SCP6, to obtain good behavior for thin or thick, isotropic or composite shells in static, free vibrations and buckling situations. A particular attention is given to the modifications made in order to avoid various numerical locking (shear, thickness and trapezoidal effects). The second part of this thesis is devoted to the geometrical nonlinear analysis. An Updated Lagrangian Formulation is developed for the analysis of shells in large displacements, large rotations and small elastic strains. The last part of the present thesis deals with the optimization of laminate structures, where design variables are the fibbers orientations or/and Young modulus. The objective function is based on the Hill criterion. To resolve the optimization problem we adopt an efficient specific adaptive response surface method, based on diffuse approximation. This technique has been shown to be more efficient than classical gradient based methods. Numerical investigations are conducted in this study to assess current procedure capabilities for standard international benchmarks. The comparison with commercial code ABAQUS shows that our models reproduce effectively the behavior of laminated shell structures and give fairly good results. Three numerical applications combining a solid-shell finite element models for the modelling of multilayered composite structures with our response surface method are presented
Lefrançois, Julie. "Optimisation du rendement d'une turbine multi-ailes à l'aide d'une méthode lagrangienne par particules vortex." Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25539/25539.pdf.
Повний текст джерелаBochud, Pascal. "Résolution spatiale non uniforme dans une méthode vortex et optimisation d'un concept de turbine à aile oscillante." Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25597/25597.pdf.
Повний текст джерелаThévenet, Jean-Baptiste. "Techniques d'optimisation avancées pour la synthèse de lois de commande." Toulouse 3, 2005. http://www.theses.fr/2005TOU30125.
Повний текст джерелаThis thesis research area belongs to the class of nonlinear semidefinite programming, an emerging and challenging domain in optimization which is of central importance in robust control and relaxation of hard decision problems. Our contribution addresses convergence of algorithms, practical implementations and testing on applications in the field of reduced-order output feedback control. Firstly, our augmented Lagrangian-type "spectral SDP" method has shown to be extremely efficient on a variety of middle-scale BMI programs, including simultaneous, structured, or mixed H2/Hinf synthesis problems. Local convergence properties of the algorithm were studied as well, as far as classical nonlinear programs are concerned. On the other hand, we then focused on nonsmooth strategies for large bilinear matrix inequalities. Problems with up to a few thousand variables were successfully handled through this method, where alternative approaches usually give failure
Bodrero, Alain. "Contrôle d'un champ acoustique à l'intérieur d'une cavité par des moyens passifs en régime harmonique." Rouen, 1999. http://www.theses.fr/1999ROUES029.
Повний текст джерелаbellaassali, said. "Contributions à l'optimisation multicritère." Phd thesis, Université de Bourgogne, 2003. http://tel.archives-ouvertes.fr/tel-00004337.
Повний текст джерелаLizy-Destrez, Stéphanie. "Operational scenarios optimization for resupply of crew and cargo of an International gateway Station located near the Earth-Moon-Lagrangian point-2." Thesis, Toulouse, ISAE, 2015. http://www.theses.fr/2015ESAE0034/document.
Повний текст джерелаIn the context of future human space exploration missions in the solar system (with an horizon of 2025) and according to the roadmap proposed by ISECG (International Space Exploration Coordination Group) [1], a new step could be to maintain as an outpost, at one of the libration points of the Earth-Moon system, a space station. This would ease access to far destinations as Moon, Mars and asteroids and would allow to test some innovative technologies, before employing them for far distant human missions. One of the main challenges will be to maintain permanently, and ensure on board crew health thanks to an autonomous space medical center docked to the proposed space station, as a Space haven. Then the main problem to solve is to manage the station servitude, during deployment (modules integration) and operational phase. Challenges lie, on a global point of view, in the design of the operational scenarios and, on a local point of view, in trajectories selection, so as to minimize velocity increments (energy consumption) and transportation duration (crew safety). Which recommendations could be found out as far as trajectories optimization is concerned, that would fulfill energy consumption, transportation duration and safety criterion? What would technological hurdles be to rise for the building of such Space haven? What would be performances to aim at for critical sub-systems? Expected results of this study could point out research and development perspectives for human spaceflight missions and above all, in transportation field for long lasting missions.Thus, the thesis project, presented here, aims at from global system life-cycle decomposition, to identify by phase operational scenario and optimize resupply vehicle mission. The main steps of this project consist in:- Bibliographical survey, that covers all involved disciplines like mission analysis (Astrodynamics, Orbital mechanics, Orthography, N-Body Problem, Rendezvous…), Applied Mathematics, Optimization, Systems Engineering….- Entire system life-cycle analysis, so as to establish the entire set of scenarios for deployment and operations (nominal cases, degraded cases, contingencies…) and for all trajectories legs (Low Earth Orbit, Transfer, Rendezvous, re-entry…)- Trade-off analysis for Space Station architecture- Modeling of the mission legs trajectories- Trajectories optimizationThree main scenarios have been selected from the results of the preliminary design of the Space Station, named THOR: the Space Station deployment, the resupply cargo missions and the crew transportation. The deep analysis of those three main steps sorted out the criticality of the rendezvous strategies in the vicinity of Lagrangian points. A special effort has been set on those approach maneuvers. The optimization of those rendezvous trajectories led to consolidate performances (in term of energy and duration) of the global transfer from the Earth to the Lagrangian point neighborhood and return. Finally, recommendations have been deduced that support the Lagrangian points importance for next steps of Human Spaceflight exploration of the Solar system
Kiran, Bangalore Ravi. "Energetic-lattice based optimization." Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1091/document.
Повний текст джерелаHierarchical segmentation has been a model which both identifies with the construct of extracting a tree structured model of the image, while also interpreting it as an optimization problem of the optimal scale selection. Hierarchical processing is an emerging field of problems in computer vision and hyper-spectral image processing community, on account of its ability to structure high-dimensional data. Chapter 1 discusses two important concepts of Braids and Energetic lattices. Braids of partitions is a richer hierarchical partition model that provides multiple locally non-nested partitioning, while being globally a hierarchical partitioning of the space. The problem of optimization on hierarchies and further braids are non-tractable due the combinatorial nature of the problem. We provide conditions, of h-increasingness, scale-increasingness on the energy defined on partitions, to extract unique and monotonically ordered minimal partitions. Furthermore these conditions are found to be coherent with the Braid structure to perform constrained optimization on hierarchies, and more generally Braids. Chapter 2 demonstrates the Energetic lattice, and how it generalizes the Lagrangian formulation of the constrained optimization problem on hierarchies. Finally in Chapter 3 we apply the method of optimization using energetic lattices to the problem of extraction of segmentations from a hierarchy, that are proximal to a ground truth set. Chapter 4 we show how one moves from the energetic lattice on hierarchies and braids, to a numerical lattice of Jordan Curves which define a continous model of hierarchical segmentation. This model enables also to compose different functions and hierarchies
Lê, Thi Hoai An. "Analyse numérique des algorithmes de l'optimisation D. C. . Approches locale et globale. Codes et simulations numériques en grande dimension. Applications." Rouen, 1994. http://www.theses.fr/1994ROUES047.
Повний текст джерелаCuesta, Ramirez Jhouben Janyk. "Optimization of a computationally expensive simulator with quantitative and qualitative inputs." Thesis, Lyon, 2022. http://www.theses.fr/2022LYSEM010.
Повний текст джерелаIn this thesis, costly mixed problems are approached through gaussian processes where the discrete variables are relaxed into continuous latent variables. the continuous space is more easily harvested by classical bayesian optimization techniques than a mixed space would. discrete variables are recovered either subsequently to the continuous optimization, or simultaneously with an additional continuous-discrete compatibility constraint that is handled with augmented lagrangians. several possible implementations of such bayesian mixed optimizers are compared. in particular, the reformulation of the problem with continuous latent variables is put in competition with searches working directly in the mixed space. among the algorithms involving latent variables and an augmented lagrangian, a particular attention is devoted to the lagrange multipliers for which a local and a global estimation techniques are studied. the comparisons are based on the repeated optimization of three analytical functions and a mechanical application regarding a beam design. an additional study for applying a proposed mixed optimization strategy in the field of mixed self-calibration is made. this analysis was inspired in an application in radionuclide quantification, which defined an specific inverse function that required the study of its multiple properties in the continuous scenario. a proposition of different deterministic and bayesian strategies was made towards a complete definition in a mixed variable setup
Ouriemchi, Mohammed. "Résolution de problèmes non linéaires par les méthodes de points intérieurs : théorie et algorithmes." Phd thesis, Université du Havre, 2005. http://tel.archives-ouvertes.fr/tel-00011376.
Повний текст джерелаDans cette thèse, nous avons utilisé une fonction barrière logarithmique. A chaque itération externe, la technique SQP se charge de produire une série de sous-problèmes quadratiques dont les solutions forment une suite, dite interne, de directions de descente pour résoudre le problème non linéaire pénalisé.
Nous avons introduit un changement de variable sur le pas de déplacement ce qui a permis d'obtenir des conditions d'optimalité plus stable numériquement.
Nous avons réalisé des simulations numériques pour comparer les performances de la méthode des gradients conjugués à celle de la méthode D.C., appliquées pour résoudre des problèmes quadratiques de région de confiance.
Nous avons adapté la méthode D.C. pour résoudre les sous-problèmes verticaux, ce qui nous a permis de ramener leurs dimensions de $n+m$ à $m+p$ ($ p < n $).
L'évolution de l'algorithme est contrôlée par la fonction de mérite. Des tests numériques permettent de comparer les avantages de différentes formes de la fonction de mérite. Nous avons introduit de nouvelles règles pour améliorer cette évolution.
Les expériences numériques montrent un gain concernant le nombre de problèmes résolus. L'étude de la convergence de notre méthode SDC, clôt ce travail.
Amdouni, Saber. "Numerical analysis of some saddle point formulation with X-FEM type approximation on cracked or fictitious domains." Thesis, Lyon, INSA, 2013. http://www.theses.fr/2013ISAL0007/document.
Повний текст джерелаThis Ph.D. thesis was done in collaboration with "La Manufacture Française des Pneumatiques Michelin". It concerns the mathematical and numerical analysis of convergence and stability of mixed or hybrid formulation of constrained optimization problem with Lagrange multiplier method in the framework of the eXtended Finite Element Method (XFEM). First we try to prove the stability of the X-FEM discretization for incompressible elastostatic problem by ensured a LBB condition. The second axis, which present the main content of the thesis, is dedicated to the use of some stabilized Lagrange multiplier methods. The particularity of these stabilized methods is that the stability of the multiplier is provided by adding supplementary terms in the weak formulation. In this context, we study the Barbosa-Hughes stabilization technique applied to the frictionless unilateral contact problem with XFEM-cut-off. Then we present a new consistent method based on local projections for the stabilization of a Dirichlet condition in the framework of extended finite element method with a fictitious domain approach. Moreover we make comparative study between the local projection stabilization and the Barbosa-Hughes stabilization. Finally we use the local projection stabilization to approximate the two-dimensional linear elastostatics unilateral contact problem with Tresca frictional in the framework of the eXtended Finite Element Method X-FEM
Chéron, Victor. "Couplage de la méthode de capture d'interface et de particules lagrangiennes pour la simulation de l'atomisation." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR097.
Повний текст джерелаThe study of the liquid jet’s atomization consisting of two immiscible phases is a fundamental research subject. The main motivations linked to the study of these phenomena are the numerous applications resulting from them. For example, in the study of the propagation of a spray within a combustion chamber or for pharmaceutical applications. Their study is carried out by a theoretical, experimental and numerical approach. Each of these techniques faces its own limitations: in the numerical study, the treatment of the droplets resulting from the jet break is a limiting factor due to the size ratio introduced. This thesis manuscript presents the coupling between an Eulerian interface treatment method and a Lagrangian particle transport method, proposing a multi-scale approach to atomization. The numerical solver Archer is used to transport a two-phase flow and to study its evolution, solving the incompressible Navier Stokes equations. The interface separating the two phases is represented by a method combining precision and robustness, the Volume of Fluid/Level-Set coupling. The discretization of the Navier Stokes equations and the transport of the interface is presented in the first part of this manuscript. This introduces the weaknesses of this method due to the multi-scale aspect of the atomized jets: the low precision of the transport of the drops resulting from the secondary atomization. The second section of this manuscript is dedicated to the introduction of Lagrangian drop transport, different approaches are implemented and validated within the computational code Archer. Then, the coupling between the Eulerien and Lagrangian solver, validated from numerical experiments, is introduced. The latter aim to present the methodology implemented to validate the coupling while respecting the conservation of time and mass. This method is then applied to academic cases to introduce the parameterization allowing the junction between the Eulerien and Lagrangien solvers. Finally, the developed method is applied to the study of an atomized jet of crossflow configuration, used in gas turbine or ramjet. The results obtained demonstrate the possibilities related to the Eulerien/Lagrangien coupling, both on the physical and numerical aspects, opening up a model of drop breakup under Lagrangien transport
Hugel, Thomas. "Estimations de satisfaisabilité." Phd thesis, Université Paris-Diderot - Paris VII, 2010. http://tel.archives-ouvertes.fr/tel-00582571.
Повний текст джерелаLiu, Yuan. "Représentation parcimonieuse basée sur la norme ℓ₀ Mixed integer programming for sparse coding : application to image denoising Incoherent dictionary learning via mixed-integer programming and hybrid augmented Lagrangian". Thesis, Normandie, 2019. http://www.theses.fr/2019NORMIR22.
Повний текст джерелаIn this monograph, we study the exact ℓ₀ based sparse representation problem. For the classical dictionary learning problem, the solution is obtained by iteratively processing two steps: sparse coding and dictionary updating. However, even the problem associated with sparse coding is non-convex and NP-hard. The method for solving this is to reformulate the problem as mixed integer quadratic programming (MIQP). Then by introducing two optimization techniques, initialization by proximal method and relaxation with augmented contraints, the algorithmis greatly speed up (which is thus called AcMIQP) and applied in image denoising, which shows the good performance. Moreover, the classical problem is extended to learn an incoherent dictionary. For dealing with this problem, AcMIQP or proximal method is used for sparse coding. As for dictionary updating, augmented Lagrangian method (ADMM) and extended proximal alternating linearized minimizing method are combined. This exact ℓ₀ based incoherent dictionary learning is applied in image recovery, which illustrates the improved performance with a lower coherence
Moubachir, Marwan. "Contrôle des phénomènes d'interaction fluide-structure, application à la stabilité aéroélastique." Phd thesis, Ecole Nationale des Ponts et Chaussées, 2002. http://tel.archives-ouvertes.fr/tel-00350505.
Повний текст джерелаHanafi, Saïd. "Contribution à la résolution de problèmes duaux de grandes tailles en optimisation combinatoire." Valenciennes, 1993. https://ged.uphf.fr/nuxeo/site/esupversions/610144f0-a159-46a9-96cc-82efb45c33b5.
Повний текст джерелаVasconcelos, Joao. "Optimisation de forme des structures électromagnétiques." Phd thesis, Ecole Centrale de Lyon, 1994. http://tel.archives-ouvertes.fr/tel-00139127.
Повний текст джерелаNeamatian, Monemi Rahimeh. "Fixed cardinality linear ordering problem, polyhedral studies and solution methods." Thesis, Clermont-Ferrand 2, 2014. http://www.theses.fr/2014CLF22516/document.
Повний текст джерелаLinear Ordering Problem (LOP) has receive significant attention in different areas of application, ranging from transportation and scheduling to economics and even archeology and mathematical psychology. It is classified as a NP-hard problem. Assume a complete weighted directed graph on V n , |V n |= n. A permutation of the elements of this finite set of vertices is a linear order. Now let p be a given fixed integer number, 0 ≤ p ≤ n. The p-Fixed Cardinality Linear Ordering Problem (FCLOP) is looking for a subset of vertices containing p nodes and a linear order on the nodes in S. Graphically, there exists exactly one directed arc between every pair of vertices in an LOP feasible solution, which is also a complete cycle-free digraph and the objective is to maximize the sum of the weights of all the arcs in a feasible solution. In the FCLOP, we are looking for a subset S ⊆ V n such that |S|= p and an LOP on these S nodes. Hence the objective is to find the best subset of the nodes and an LOP over these p nodes that maximize the sum of the weights of all the arcs in the solution. Graphically, a feasible solution of the FCLOP is a complete cycle-free digraph on S plus a set of n − p vertices that are not connected to any of the other vertices. There are several studies available in the literature focused on polyhedral aspects of the linear ordering problem as well as various exact and heuristic solution methods. The fixed cardinality linear ordering problem is presented for the first time in this PhD study, so as far as we know, there is no other study in the literature that has studied this problem. The linear ordering problem is already known as a NP-hard problem. However one sees that there exist many instances in the literature that can be solved by CPLEX in less than 10 seconds (when p = n), but once the cardinality number is limited to p (p < n), the instance is not anymore solvable due to the memory issue. We have studied the polytope corresponding to the FCLOP for different cardinality values. We have identified dimension of the polytope, proposed several classes of valid inequalities and showed that among these sets of valid inequalities, some of them are defining facets for the FCLOP polytope for different cardinality values. We have then introduced a Relax-and-Cut algorithm based on these results to solve instances of the FCLOP. To solve the instances of the problem, in the beginning, we have applied the Lagrangian relaxation algorithm. We have studied different relaxation strategies and compared the dual bound obtained from each case to detect the most suitable subproblem. Numerical results show that some of the relaxation strategies result better dual bound and some other contribute more in reducing the computational time and provide a relatively good dual bound in a shorter time. We have also implemented a Lagrangian decomposition algorithm, decom-6 posing the FCLOP model to three subproblems (instead of only two subproblems). The interest of decomposing the FCLOP model to three subproblems comes mostly from the nature of the three subproblems, which are relatively quite easier to solve compared to the initial FCLOP model. Numerical results show a significant improvement in the quality of dual bounds for several instances. We could also obtain relatively quite better dual bounds in a shorter time comparing to the other relaxation strategies. We have proposed a cutting plane algorithm based on the pure relaxation strategy. In this algorithm, we firstly relax a subset of constraints that due to the problem structure, a very few number of them are active. Then in the course of the branch-and-bound tree we verify if there exist any violated constraint among the relaxed constraints or. Then the characterized violated constraints will be globally added to the model. (...)
Savourey, David. "Ordonnancement sur machines parallèles : minimiser la somme des coûts." Phd thesis, Université de Technologie de Compiègne, 2006. http://tel.archives-ouvertes.fr/tel-00156405.
Повний текст джерелаinférieures a également été réalisée. Enfin, nous avons proposé une méthode de résolution exacte utilisant les règles de dominance ainsi que les bornes inférieures.
Tran, Ngoc Nguyen. "Infeasibility detection and regularization strategies in nonlinear optimization." Thesis, Limoges, 2018. http://www.theses.fr/2018LIMO0059/document.
Повний текст джерелаThis thesis is devoted to the study of numerical algorithms for nonlinear optimization. On the one hand, we propose new strategies for the rapid infeasibility detection. On the other hand, we analyze the local behavior of primal-dual algorithms for the solution of singular problems. In the first part, we present a modification of an augmented Lagrangian algorithm for equality constrained optimization. The quadratic convergence of the new algorithm in the infeasible case is theoretically and numerically demonstrated. The second part is dedicated to extending the previous result to the solution of general nonlinear optimization problems with equality and inequality constraints. We propose a modification of a mixed logarithmic barrier-augmented Lagrangian algorithm. The theoretical convergence results and the numerical experiments show the advantage of the new algorithm for the infeasibility detection. In the third part, we study the local behavior of a primal-dual interior point algorithm for bound constrained optimization. The local analysis is done without the standard assumption of the second-order sufficient optimality conditions. These conditions are replaced by a weaker assumption based on a local error bound condition. We propose a regularization technique of the Jacobian matrix of the optimality system. We then demonstrate some boundedness properties of the inverse of these regularized matrices, which allow us to prove the superlinear convergence of our algorithm. The last part is devoted to the local convergence analysis of the primal-dual algorithm used in the first two parts of this thesis. In practice, it has been observed that this algorithm converges rapidly even in the case where the constraints do not satisfy the Mangasarian-Fromovitz constraint qualification. We demonstrate the superlinear and quadratic convergence of this algorithm without any assumption of constraint qualification
Bourbon, Fabienne. "Modélisation, simulation numérique et contrôle optimal de l'évolution de la configuration du plasma pour le Tokamak NET et pour la génération future de réacteurs de fusion." Phd thesis, Grenoble 1, 1993. http://tel.archives-ouvertes.fr/tel-00343468.
Повний текст джерелаBlagouchine, Iaroslav. "Modélisation et analyse de la parole : Contrôle d’un robot parlant via un modèle interne optimal basé sur les réseaux de neurones artificiels. Outils statistiques en analyse de la parole." Thesis, Aix-Marseille 2, 2010. http://www.theses.fr/2010AIX26666.
Повний текст джерелаThis Ph.D. dissertation deals with speech modeling and processing, which both share the speech quality aspect. An optimum internal model with constraints is proposed and discussed for the control of a biomechanical speech robot based on the equilibrium point hypothesis (EPH, lambda-model). It is supposed that the robot internal space is composed of the motor commands lambda of the equilibrium point hypothesis. The main idea of the work is that the robot movements, and in particular the robot speech production, are carried out in such a way that, the length of the path, traveled in the internal space, is minimized under acoustical and mechanical constraints. Mathematical aspect of the problem leads to one of the problems of variational calculus, the so-called geodesic problem, whose exact analytical solution is quite complicated. By using some empirical findings, an approximate solution for the proposed optimum internal model is then developed and implemented. It gives interesting and challenging results, and shows that the proposed internal model is quite realistic; namely, some similarities are found between the robot speech and the real one. Next, by aiming to analyze speech signals, several methods of statistical speech signal processing are developed. They are based on higher-order statistics (namely, on normalized central moments and on the fourth-order cumulant), as well as on the discrete normalized entropy. In this framework, we also designed an unbiased and efficient estimator of the fourth-order cumulant in both batch and adaptive versions
Bourdin, Loïc. "Contributions au calcul des variations et au principe du maximum de Pontryagin en calculs time scale et fractionnaire." Thesis, Pau, 2013. http://www.theses.fr/2013PAUU3009/document.
Повний текст джерелаThis dissertation deals with the mathematical fields called calculus of variations and optimal control theory. More precisely, we develop some aspects of these two domains in discrete, more generally time scale, and fractional frameworks. Indeed, these two settings have recently experience a significant development due to its applications in computing for the first one and to its emergence in physical contexts of anomalous diffusion for the second one. In both frameworks, our goals are: a) to develop a calculus of variations and extend some classical results (see below); b) to state a Pontryagin maximum principle (denoted in short PMP) for optimal control problems. Towards these purposes, we generalize several classical variational methods, including the Ekeland’s variational principle (combined with needle-like variations) as well as variational invariances via the action of groups of transformations. Furthermore, the investigations for PMPs lead us to use fixed point theorems and to consider the Lagrange multiplier technique and a method based on a conic implicit function theorem. This manuscript is made up of two parts : Part A deals with variational problems on time scale and Part B is devoted to their fractional analogues. In each of these parts, we follow (with minor differences) the following organization: 1. obtaining of an Euler-Lagrange equation characterizing the critical points of a Lagrangian functional; 2. statement of a Noether-type theorem ensuring the existence of a constant of motion for Euler-Lagrange equations admitting a symmetry;3. statement of a Tonelli-type theorem ensuring the existence of a minimizer for a Lagrangian functional and, consequently, of a solution for the corresponding Euler-Lagrange equation (only in Part B); 4. statement of a PMP (strong version in Part A and weak version in Part B) giving a necessary condition for the solutions of general nonlinear optimal control problems; 5. obtaining of a Helmholtz condition characterizing the equations deriving from a calculus of variations (only in Part A and only in the purely continuous and purely discrete cases). Some Picard-Lindelöf type theorems necessary for the analysis of optimal control problems are obtained in Appendices
Delbos, Frédéric. "Problèmes d'Optimisation Non Linéaire avec Contraintes en Tomographie de Réflexion 3D." Paris 6, 2004. http://www.theses.fr/2004PA066082.
Повний текст джерелаFrankel, Pierre. "Comportement asymptotique de systèmes dynamiques discrets et continus en Optimisation et EDP: algorithmes de minimisation proximale alternée et dynamique du deuxième ordre à dissipation évanescente." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2001. http://tel.archives-ouvertes.fr/tel-00637390.
Повний текст джерелаFrankel, Pierre. "Comportement asymptotique de systèmes dynamiques discrets et continus en Optimisation et EDP : algorithmes de minimisation proximale alternée et dynamique du deuxieme ordre à dissipation évanescente." Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20066.
Повний текст джерелаThe first part of this thesis is devoted to the study of the asymptotic behavior of solutions of a second order dynamic system with vanishing dissipation. The dynamic system is studied in its continuous version and in its discrete version via an algorithm.The second part is about the study of several proximal-type algorithms. We show that these algorithms converge to solutions of some minimization problems. In each case, an application is given in the area of domain decomposition for PDE's
Srour, Ali. "Etudes de deux approches mathématiques complémentaires pour un problème de reconstruction tomographique." Thesis, Tours, 2008. http://www.theses.fr/2008TOUR4016/document.
Повний текст джерелаThe thesis at hand is composed of four parts. The first of which is devoted to present our model of tomographic reconstruction. The second part treats a non-differentiable variational problem with a non-convex constraint the interior of which is empty for usual topologies. A numerical study of the above approach is elaborated in the third part. A numerical scheme is derived based upon our optimal system, the method of Uzawa and a gradient descent method. In the last part, we use a level-set approach to solve the front propagation problem. A second order Hamilton-Jacobi type equation with a non-local term comes into play. We prove the existence and uniqueness of a viscosity solution in both compact and non-compact fronts cases
Mandallena, Michel. "Utilisation de méthodes de contrôle optimal pour résoudre des problèmes liés à la furtivité électromagnétique." Grenoble 1, 1993. http://www.theses.fr/1993GRE10160.
Повний текст джерелаLaborde, Maxime. "Systèmes de particules en interaction, approche par flot de gradient dans l'espace de Wasserstein." Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLED014/document.
Повний текст джерелаSince 1998 and the seminal work of Jordan, Kinderlehrer and Otto, it is well known that a large class of parabolic equations can be seen as gradient flows in the Wasserstein space. This thesis is devoted to extensions of this theory to equations and systems which do not have exactly a gradient flow structure. We study different kind of couplings. First, we treat the case of nonlocal interactions in the drift. Then, we study cross diffusion systems which model congestion for several species. We are also interested in reaction-diffusion systems as diffusive prey-predator systems or tumor growth models. Finally, we introduce a new class of systems where the interaction is given by a multi-marginal transport problem. In many cases, we give numerical simulations to illustrate our theorical results
Omnès, Florian. "Geometry optimization applied to incompressible fluid mechanics." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS278.
Повний текст джерелаThis applied mathematics thesis is dedicated to the modelling and exploration of numerical geometry optimization techniques. The first chapter is dedicated to a geometry optimization algorithm implemented in optiflow, in the case where the boundary to optimize is associated to no-slip conditions. The implementation is online and comes with a manual. It is therefore possible to use it for real-life applications such as pipeline or air conditioning, etc. In the second chapter, I describe a way to model fluid flow through an aquaporine. After making the fluid model precise, the existence of an optimal shape for the dissipated energy criterion is proven. Partial boundary conditions make appear difficulties in the sensitivity analysis of the optimization problem. A specific numerical treatment is presented to overcome this difficulty. Finally, several numerical examples are presented and commented
Tran, Quang Huy. "Résolution et étude numériques de quelques problèmes de propagation d'ondes acoustiques en géophysique." Paris, ENMP, 1994. http://www.theses.fr/1994ENMP0494.
Повний текст джерелаHatchi, Roméo. "Analyse mathématique de modèles de trafic routier congestionné." Thesis, Paris 9, 2015. http://www.theses.fr/2015PA090048/document.
Повний текст джерелаThis thesis is devoted to the mathematical analysis of some models of congested road traffic. The essential notion is the Wardrop equilibrium. It continues Carlier and Santambrogio's works with coauthors. With Baillon they studied the case of two-dimensional cartesian networks that become very dense in the framework of $\Gamma$-convergence theory. Finding Wardrop equilibria is equivalent to solve convex minimisation problems.In Chapter 2 we look at what happens in the case of general networks, increasingly dense. New difficulties appear with respect to the original case of cartesian networks. To deal with these difficulties we introduce the concept of generalized curves. Structural assumptions on these sequences of discrete networks are necessary to obtain convergence. Sorts of Finsler distance are used and keep track of anisotropy of the network. We then have similar results to those in the cartesian case.In Chapter 3 we study the continuous model and in particular the limit problems. Then we find optimality conditions through a duale formulation that can be interpreted in terms of continuous Wardrop equilibria. However we work with generalized curves and we cannot directly apply Prokhorov's theorem, as in \cite{baillon2012discrete, carlier2008optimal}. To use it we consider a relaxed version of the limit problem with Young's measures. In Chapter 4 we focus on the long-term case, that is, we fix only the distributions of supply and demand. As shown in \cite{brasco2013congested} the problem of Wardrop equilibria can be reformulated in a problem à la Beckmann and reduced to solve an elliptic anisotropic and degenerated PDE. We use the augmented Lagrangian scheme presented in \cite{benamou2013augmented} to show a few numerical simulation examples. Finally Chapter 5 is devoted to studying Monge problems with as cost a Finsler distance. It leads to minimal flow problems. Discretization of these problems is equivalent to a saddle-point problem. We then solve it numerically again by an augmented Lagrangian algorithm