Дисертації з теми "Système homogène"
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Wang, Siyuan. "Contôle homogène de quadrator : théorie et expérience." Thesis, Centrale Lille Institut, 2020. http://www.theses.fr/2020CLIL0026.
In the past several decades, quadrotor control problems attract more attentions of the researcher comparing withother flying vehicles. However, most of the commercial products still use linear PID controller, which provides sufficientlygood performance. Development of a controller, which would convince theindustry to use it instead of linear PID, is still a challenge. The aim of this thesis is to show that homogeneous controller is a possiblealternative to linear one. For this purpose, a new methodof upgrading linear algorithm to homogeneous one is proposed. It uses the gains of linear controller/observer provided by the manufacturer for tuning of homogeneous algorithm. The experimental results support the theoretical developments and confirm a significant improvement of quadrotor’s control quality:better precision, more robustness and faster response
Morris, Christophe. "Le système d'Einstein-Dirac d'un univers homogène et isotrope." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121581.
D'abord, l'article [8] est situé dans son contexte et les points d'intérêt decet article sont soulevés. Il en découle une étude approfondie, où les démarchesde cet article sont suivies, en se référant à d'autres articles (des mêmes auteursou non). L'obtention du système d'Einstein-Dirac dans [8] est décrite. Puis,les résultats exposés sur la séparation de l'équation de Dirac sur la sphère dedimension trois dans [9] et qui sont détaillés en annexe, sont utilisés. L'utilisationde ces résultats avec l'expression classique du tenseur d'énergie-impulsion,dont la nullité de la divergence est démontrée, permet de réduire le systèmed'Einstein-Dirac en un système de deux EDO couplées avec une condition denormalisation.Pour étudier ce système, le formalisme de Bloch est brièvement introduit.Il est ensuite utilisé de façon a simplifier l'étude et la résolution de ce système.Les solutions du système résultant sont tirées de [8] et analysées de façon essentiellementqualitative. La solution approchée déterminée dans [7] est décriteet utilisé pour poser une borne inférieure approximative sur la probabilité quele Big-Bang soit évité.
Nguyen, Valérie. "Système de création de champ magnétique homogène à aimants ferrites pour l’imagerie RMN." Grenoble INPG, 1996. http://www.theses.fr/1996INPG0120.
Wazner, Alain. "Formes canoniques invariantes d'un système linéaire différentiel homogène, polygone de Newton, calcul de la partie exponentielle des solutions formelles." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10233.
Majd, Abderrazzak. "Analyse asymptotique du problème de jonctions dans un système non homogène de barres élastiques : développement asymptotique et couches limites." Saint-Etienne, 1998. http://www.theses.fr/1998STET4012.
Kopka, Bernard. "Étude et validation d'une redondance homogène d'ordre deux à décalage temporel pour des applications à haut niveau de sécurité." Nancy 1, 1988. http://www.theses.fr/1988NAN10041.
Hébrard, Frédéric. "Mode de fonctionnement du cobalt dans l'hydroformylation des alcènes catalysée par le système {[Co2(CO)8]/Pyridine/Liquide Ionique}." Toulouse, INPT, 2006. http://ethesis.inp-toulouse.fr/archive/00000397/.
Hydroformylation of alkenes remains, nowadays, a major application in homogeneous catalysis. Annual production of oxo products is still increasing and cobalt carbonyl complexes are playing an important role in this field. The Institut Français du Pétrole has developed a biphasic catalytic system based on the association of a cobalt complex with a nitrogen-containing Lewis base in the presence of a non aqueous ionic liquid, which solves some of the former processes concerns of catalyst recycling and retains satisfactory catalytic activity. In this work, we focused on the understanding of the mechanisms involved in the catalytic behaviour of the {[Co2(CO)8]/Py/IL} system by the mean of high-pressure IR spectroscopic studies. Catalytic activity is to be attributed to the hydridocarbonyl complex [HCo(CO)4] of which formation lies on already suggested redox equilibriums. Cobalt is involved in this system under various forms, within which ionic [PyH][Co(CO)4] was identified as a potential source for [HCo(CO)4], according to an acid-base equilibrium. We also present here the X-ray crystallographic structure for the [Co(Py)6][Co(CO)4]2 ionic complex
Catastini, Carole. "Dégradation de polluants organiques sous exitation directe et en photocatalyse homogène par le système Fer (III)/Fer (II) en solution aqueuse : du processus primaire à la minéralisation." Clermont-Ferrand 2, 2002. http://www.theses.fr/2002CLF22390.
Nguyen, Khac Minh Huy. "Activation de liaisons C-H au moyen d’un système catalytique bio-inspiré pour la synthèse d’hétérocycles d’intérêt pharmacologique." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCB023.
Naturally occurring metalloenzymes constitute a rich source of inspiration for the design of synthetic catalysts because of their ability to perform controlled aerobic oxidations under very mild conditions. Among metalloenzymes, copper amine oxidases (CuAOs) promote selective aerobic oxidation of primary amines through the cooperation of a quinone-based cofactor (topaquinone) and a copper ion. Recently, there has been a boost in the development of biomimetic catalysts for the aerobic oxidation of amines to imines owing to the importance of imines as pivotal intermediates in the synthesis of fine chemicals and pharmaceuticals. In our laboratory, a CuAOs-like homogeneous co-catalytic system has been described for the atom-economical oxidation of primary amines to imines, under ambient air. The catalytic process combines two redox couples in a way reminiscent of CuAOs: the o-iminoquinone organocatalyst 1ox, generated in situ from the corresponding o-aminophenol 1red, is the substrate-selective catalyst, whereas the copper (II) salt serves as an electron transfer mediator. Interestingly, low loadings of biocompatible CuII and organocatalyst 1ox are sufficient to activate the α-C-H bond of primary aliphatic amines, which are converted, under ambient air, into cross-coupled imines through a transamination process that leads to the homocoupled imine intermediate, followed by dynamic transimination. The mild reaction conditions are highly favorable from a synthetic viewpoint, in particular for trapping the unstable alkylimines in situ for further reactions. So, we have envisioned the use of this bioinspired co-catalytic system in the one-pot synthesis of heterocycles of pharmacological interest. In the first part of the thesis, we envisioned that the Cu(II)/1ox cooperative system might be utilized to synthesize novel 1,4-benzoxazine derivatives. In the specific case of R1R2CHCH2NH2 amines, the catalytic process should stop after a few turnovers, because the catalyst 1ox should be trapped through inverse-electron-demand Diels-Alder (IEDDA) reaction with the simultaneously in situ generated tautomeric enamine form of the alkylimine extruded during the catalytic process, leading to 1,4-benzoxazine derivatives. Unfortunately, this protocol failed to produce the expected cycloadducts in acceptable yields as enamines rapidly decomposed under ambient air. For this reason, we have developed a tandem oxidation-inverse electron demand Diels-Alder reaction as an alternative: a stoichiometric amount of activated MnO2, in deaerated methanol, was then sufficient to convert various o-aminophenol derivatives into o-iminoquinone heterodienes which were trapped in situ by different enamine dienophiles leading to the expected 1,4-benzoxazine derivatives under mild conditions. The possibility of introducing variations in both cycloaddition partners led to highly substituted 1,4-benzoxazine cycloadducts with up to five elements of diversity. Among these compounds, a 3,3-diphenyl-substituted-1,4-benzoxazine derivative was identified as an effective neuroprotective agent in newborn mice, suggesting that it could be a potential candidate for the treatment and prevention of cerebral palsy. In the second part of the thesis, the Cu(II)/1ox cooperative system has been successfully used for the catalytic oxidative coupling of a diverse range of activated and non-activated primary amines with o-amino-anilines under ambient air leading to benzimidazoles of biological interest through multistep oxidation and nucleophilic addition reactions. Through the variation of both solvent and coupling partners, MeOH proved to be the best solvent for this transformation because it provided the ideal balance of 1ox solvation and reaction rate, except when reactive N-alkyl o-aminoanilines were used as in situ imine traps, due to the concomitant formation of a benzimidazole byproduct originated from MeOH itself. (...)
Tricot-Censier, Pascal. "Étude et réalisation d'une passerelle entre un réseau MIL1553 et un réseau ETHERNET : implantation du réseau homogène OS9NET et du réseau hétérogène TCP/IP sur le système d'exploitation temps réel OS-9/68000." Paris 11, 1989. http://www.theses.fr/1989PA112241.
Almallah, Hamzé. "Systèmes confinants pour la catalyse homogène." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAF011.
Described herein are the stepwise syntheses and properties of three types of complexes based on sterically encumbered N-heterocyclic carbenes (NHCs): 1) Pd-PEPPSI complexes with an unsymmetrical imidalolylidene ligand having its N atoms substituted by a bulky 9-alkyl-9-fluorenyl (AF) group and an aryl group. These turned out to be very active Suzuki-Miyaura cross coupling catalysts with an activity comparable to previously reported, highly performing "symmetrical" analogues which bear two identical AF substituents. These findings illustrate the high stabilising effect of each individual AF group; 2) Trigonal copper(I) complexes with the general formula [Cu(Im)(2,2'-dipyridylamine)]BF4 in which the NHC ligands are symmetrical or not. Here again the AF substituents ensure complex stability with respect to air when compared to analogues displaying sterically non-bulky substituents. One of the complexes, namely [Cu((EtF,Ph)-Im)(2,2'-dipyridylamine)]BF4, was found to be strongly luminescent in solution and in the solid state; 3) Pd-PEPPSI complexes in which calix[4]arene-substituted phenyl moieties have been grafted on both N atoms, these behaving as potential receptor units. Owing to the presence of the calixarene termini, complexes of this type were found to self-assemble, thereby resulting in dimers with sterically highly protected metal centres. The formation of such species was correlated to the catalytic performance of these complexes
Zenati, Hanine. "Méthodes de stabilisation des systèmes homogènes." Metz, 1999. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1999/Zenati.Hanine.SMZ9912.pdf.
Dutilleul, Tom. "Dynamique chaotique des espaces-temps spatialement homogènes." Thesis, Paris 13, 2019. http://www.theses.fr/2019PA131019.
In 1963, Belinsky, Khalatnikov and Lifshitz have proposed a conjectural description of the asymptotic geometry of cosmological models in the vicinity of their initial singularity. In particular, it is believed that the asymptotic geometry of generic spatially homogeneous spacetimes should display an oscillatory chaotic behaviour modeled on a discrete map’s dynamics (the so-called Kasner map). We prove that this conjecture holds true, if not for generic spacetimes, at least for a positive Lebesgue measure set of spacetimes. In the context of spatially homogeneous spacetimes, the Einstein field equations can be reduced to a system of differential equations on a finite dimensional phase space: the Wainwright-Hsu equations. The dynamics of these equations encodes the evolution of the geometry of spacelike slices in spatially homogeneous spacetimes. Our proof is based on the non-uniform hyperbolicity of the Wainwright-Hsu equations. Indeed, we consider the return map of the solutions of these equations on a transverse section and prove that it is a non-uniformly hyperbolic map with singularities. This allows us to construct some local stable manifolds à la Pesin for this map and to prove that the union of the orbits starting in these local stable manifolds cover a positive Lebesgue measure set in the phase space. The chaotic oscillatory behaviour of the corresponding spacetimes follows. The Wainwright-Hsu equations turn out to be quite interesting and challenging from a purely dynamical system viewpoint. In order to understand the asymptotic behaviour of (many of) the solutions of these equations, we will in particular be led to: • carry a detailed analysis of the local dynamics of a vector field in the neighborhood of degenerate nonlinearizable partially hyperbolic singularities, • deal with non-uniformly hyperbolic maps with singularities for which the usual theory (due to Pesin and Katok-Strelcyn) is not relevant due to the poor regularity of the maps, • consider some unusual arithmetic conditions expressed in terms of continued fractions and use some rather sophisticated ergodic properties of the Gauss map to prove that these properties are generic
Abbaci, Mohamed. "Espaces homogènes de Poisson." Lyon 1, 1986. http://www.theses.fr/1986LYO11705.
Etcheverry, Gibran. "Réalisation et identification de systèmes bilinéaires homogènes." Phd thesis, Université Paul Sabatier - Toulouse III, 2006. http://tel.archives-ouvertes.fr/tel-00130071.
Etcheverry, Doger Gibran. "Réalisation et identification de systèmes bilinéaires homogènes." Toulouse 3, 2006. http://www.theses.fr/2006TOU30217.
Nguyen, Hong-Thai. "Des systèmes de TA homogènes aux systèmes de TAO hétérogènes." Phd thesis, Université Joseph Fourier (Grenoble), 2009. http://tel.archives-ouvertes.fr/tel-00447571.
Nisand, Gabriel. "Déterminants, mécanismes et impacts de la spécialisation médicale : modélisation d'un outil de mesure." Nancy 1, 1995. http://www.theses.fr/1995NAN19014.
SAHMIM, Slah. "Un schéma aux volumes finis avec matrice signe pour les systèmes non homogènes." Phd thesis, Université Paris-Nord - Paris XIII, 2005. http://tel.archives-ouvertes.fr/tel-00010000.
Laduye, Guillaume. "CVD du carbure de silicium à partir du système SiHxCl4-x/CyHz/H2 : étude expérimentale et modélisation." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0116/document.
Silicon carbide (SiC) is material of choice for the matrix of Ceramic Matrix Composites (CMC).CH3SiCl3/H2 mixtures are currently used as gas precursor for the synthesis of the CVI-SiC matrices.The present work considers the dual-source approach with two separate carbon and silicon precursorsmolecules.In the case of SiHCl3/C3H8/H2 mixture, systematic studies of total flow rate, temperature, total pressureand C/Si ratio of initial gaseous phase are realized. Kinetics obtained with growth rate measurements and solid composition are compared with results from CH3SiCl3/H2 mixture. On the basis of the apparent reaction orders and activation energies, experimental kinetic laws are derived. Through IRTF analysis of the gas phase, the partial pressures of the different stable products are correlated with deposition kinetic and solid composition. Results obtained in gas-phase kinetic simulation show a good correlation with the experimental results and a mechanism of homogeneous decomposition is proposed. A better understanding of the role of the principal species in homogenous and heterogeneous phase is obtained through the study of six other gas systems and the roles of some effective precursors are discussed. Finally, infiltration results of porous material models with different precursor systems reveal significant improvements as homogeneity of kinetic deposit.Hence, favourable conditions to silicon carbide infiltration can be obtained by adapting the reactivity of the gas phase, with the choice of initial precursors and homogeneous chemistry associated. Asystematic study of the process evidences promising working windows for the infiltration of pure SiCin porous performs
Chen, Guoting. "Solutions formelles de systèmes d'équations différentielles ordinaires linéaires homogènes." Phd thesis, Grenoble 1, 1990. http://tel.archives-ouvertes.fr/tel-00338379.
Trova, Audrey. "Gravité des systèmes verticalement homogènes : applications aux disques astrophysiques." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00955555.
Xu, Liping. "Contribution à l'étude de l'équation de Boltzmann homogène." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066018/document.
This thesis mainly studies the 3D homogeneous Boltzmann equation for hard potentials and moderately soft potentials and the equivalence between some jumping SDE and the corresponding PDE. In particular, we compute the multifractal spectrum of some stochastic processes, study the well-posedness and the propagation of chaos for the Boltzmann equation. The purpose of the first chapter is to study the pathwise properties of the stochastic process $(V_t)_{t\geq0}, representing the time-evolution of the velocity of a typical particle in a gas modeled by the Boltzmann equation for hard or moderately potentials. We show that this process is multifractal and has a deterministic spectrum. For hard potentials, we also give the multifractal spectrum of the process $X_t =\int_0^t V_s ds$, representing the time-evolution of the position of the typical particle. The second chapter is devoted to study the uniqueness of the weak solution to the Boltzmann equation in the class of all measure solutions, in the case of moderately soft potentials. This allows us to obtain a quantitive rate of propagation of chaos for Nanbu particle system for this singular interaction. Finally in the third chapter, we extend Figalli’s work [19] to study the relation between some jumping SDE and the corresponding Fokker-Planck equation. We prove that for any weak solution $(ft)_{t\in[0,T]}$ of the PDE, there exists a weak solution to the SDE of which the time-marginals are given by the family $(f_t)_{t\in[0,T]$
Colombet, Laurent. "Parallélisation d'applications pour des réseaux de processeurs homogènes ou hétérogènes." Grenoble INPG, 1994. http://tel.archives-ouvertes.fr/tel-00005084.
The aim of this thesis is to study and develop efficient methods for parallelization of scientific applications on parallel computers with distributed memory. In the first part we present two libraries of PVM((\it Parallel Virtual Machine)) and MPI ((\it Message Passing Interface)) communication tools. They allow implementation of programs on most parallel machines, but also on heterogeneous computer networks. This chapter illustrates the problems faced when trying to evaluate performances of networks with heterogeneous processors. To evaluate such performances we modified and adapted the concepts of speed-up and efficiency to account for heterogeneity. The second part deals with a study of parallel application libraries such as ScaLAPACK and with the development of communication masking techniques. The general concept is based on communication anticipation, in particular by pipelining message sending operations. Experimental results on Cray T3D and IBM SP1 machines validates the theoretical studies performed on basic algorithms of the libraries discussed above
Spaenlehauer, Pierre-Jean. "Résolution de systèmes multi-homogènes et déterminantiels algorithmes - complexité - applications." Paris 6, 2012. http://www.theses.fr/2012PA066467.
Multivariate polynomial systems arising in Engineering Science often carryalgebraic structures related to the problems they stem from. Inparticular, multi-homogeneous, determinantal structures and booleansystems can be met in a wide range of applications. A classical method to solve polynomial systems is to compute a Gröbner basis ofthe ideal associated to the system. This thesis provides new tools forsolving such structured systems in the context of Gröbner basis algorithms. On the one hand, these tools bring forth new bounds on the complexity of thecomputation of Gröbner bases of several families of structured systems(bilinear systems, determinantal systems, critical point systems,boolean systems). In particular, it allows the identification of families ofsystems for which the complexity of the computation is polynomial inthe number of solutions. On the other hand, this thesis provides new algorithms which takeprofit of these algebraic structures for improving the efficiency ofthe Gröbner basis computation and of the whole solving process(multi-homogeneous systems, boolean systems). These results areillustrated by applications in cryptology (cryptanalysis of MinRank),in optimization and in effective real geometry (critical pointsystems)
Bévière, Stéphane. "Etudes mécanistiques de l'oxydation des hydrocarbures saturés à l'aide des Systèmes de GIF." Aix-Marseille 3, 1993. http://www.theses.fr/1993AIX30038.
Mrabet, Zouhaier. "Fiabilité des remblais homogènes compactés." Vandoeuvre-les-Nancy, INPL, 1997. http://www.theses.fr/1997INPL088N.
ZENATI, HANINE Sallet Gauthier. "METHODES DE STABILISATION DES SYSTEMES HOMOGENES /." [S.l.] : [s.n.], 1999. ftp://ftp.scd.univ-metz.fr/pub/Theses/1999/Zenati.Hanine.SMZ9912.pdf.
Audiard, Corentin. "Problèmes aux limites dispersifs linéaires non homogènes, application au système d'Euler-Korteweg." Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00832913.
Audiard, Corentin. "Problèmes aux limites dispersifs linéaires non homogènes, application au système d’Euler-Korteweg." Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10261/document.
The main aim of this thesis is to obtain well-posedness results for boundary value problems especially with non-homogeneous boundary conditions. The approach that we chose here is to adapt technics from the classical theory of hyperbolic boundary value problems (for which we give a brief survey in the first chapter, and a slight generalization). In chapter 3 we delimitate a class of linear dispersive equations, and we obtain well-posedness results for corresponding boundary value problems in chapter 4.The leading thread of this memoir is the Euler-Korteweg model. The boundary value problem for a linearized version is investigated in chapter 2, and the Kato-smoothing effect is proved (also for the linearized model) in chapter 3. Finally, the numerical analysis of the model is made in chapter 5. To begin with, we use the previous abstract results to show a simple way of deriving the so-called transparent boundary conditions for the equations outlined in chapter 3, and those conditions are then used to numerically solve the semi-linear Euler-Korteweg model. This allow us to observe the stability and instability of solitons, as well as a finite time blow up
Merine, Omar. "Controlabilité des systèmes bilinéaires homogènes à contrôles non bornés dans R3." Metz, 1985. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1985/Merine.Omar.SMZ8503.pdf.
Eich, Andreas. "Elektrorheologie homogener Systeme nematische Flüssigkristalle und isotrope Polymerlösungen /." [S.l. : s.n.], 2002. http://ArchiMeD.uni-mainz.de/pub/2002/0151/diss.pdf.
Faucher, Eric. "Simulation numérique des écoulements unidimensionnels instationnaires avec autovaporisation." Phd thesis, Université Paris XII Val de Marne, 2000. http://tel.archives-ouvertes.fr/tel-01026372.
Jollet, Véronique. "Complexes de fer bio inspirés pour la catalyse d'oxydation : systèmes homogènes et supportés." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00915279.
Arndt, Oliver Jakob [Verfasser]. "Modellierung von paralleler Software für homogene und heterogene Multiprozessor-Systeme / Oliver Jakob Arndt." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2020. http://d-nb.info/121542731X/34.
Sahmim, Slah. "Un schéma aux volumes finis avec matrice signe pour les systèmes non homogènes." Paris 13, 2005. http://www.theses.fr/2005PA132012.
Cepeda, Chiluisa Eduardo. "Contribution à l'étude probabiliste et numérique d'équations homogènes issues de la physique statistique : coagulation-fragmentation." Phd thesis, Université Paris-Est, 2013. http://tel.archives-ouvertes.fr/tel-00952117.
Le, Doussal Pierre. "Transport dans les systemes desordonnes : lois d'echelle et intermittence, quelques proprietes remarquables des modeles de spin homogenes ou desordonnes." Paris 6, 1987. http://www.theses.fr/1987PA066476.
Girardin, Léo. "Phénomènes de propagation et systèmes de réaction-diffusion pour la dynamique des populations en milieu homogène ou périodique." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS147/document.
This thesis is dedicated to the study of propagation properties of various reaction–diffusion systems coming from population dynamics. In the first part, we study the strong competition limit of competition–diffusion systems with two species. Thanks to the spatial segregation, we determine the sign of the speed of the bistable traveling wave. The generalization to bistable pulsating fronts in spatially periodic media is then considered in order to study the role of spatial heterogeneity. We find a condition sufficient for the existence of such fronts as well as a condition sufficient for the existence of stable steady states which might on the contrary block the propagation. Then we show that whenever a family of strongly competing pulsating fronts exists, we can establish a result very similar to the one obtained in homogeneous media. In the second part, systems of KPP type with any number of species are considered. We study the existence of steady states and traveling waves, the qualitative properties of these solutions as well as the asymptotic speed of spreading of certain solutions of the Cauchy problem. This settles several open questions on the prototypical KPP systems that are mutation–competition–diffusion systems. In the third part, we go back to competition–diffusion systems with two species. Considering this time the monostable case, we study the asymptotic speeds of spreading of certain solutions of the Cauchy problem. By so doing, we show the existence of propagating terraces describing the invasion of an uninhabited territory by a weak but fast competitor followed by the invasion by a strong but slow competitor
Verron, Thibaut. "Régularisation du calcul de bases de Gröbner pour des systèmes avec poids et déterminantiels, et application en imagerie médicale." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066355/document.
Polynomial system solving is a problem with numerous applications, and Gröbner bases are an important tool in this context. Previous studies have shown that systèmes arising in applications usually exhibit more structure than arbitrary systems, and that these structures can be used to make computing Gröbner bases easier.In this thesis, we consider two examples of such structures. First, we study weighted homogeneous systems, which are homogeneous if we give to each variable an arbitrary degree. This structure appears naturally in many applications, including a cryptographical problem (discrete logarithm). We show how existing algorithms, which are efficient for homogeneous systems, can be adapted to a weighted setting, and generically, we show that their complexity bounds can be divided by a factor polynomial in the product of the weights.Then we consider a real roots classification problem for varieties defined by determinants. This problem has a direct application in control theory, for contrast optimization in magnetic resonance imagery. This specific system appears to be out of reach of existing algorithms. We show how these algorithms can benefit from the determinantal structure of the system, and as an illustration, we answer the questions from the application to contrast optimization
Bui, Quang Anh. "Vers un système omni-langage de recherche de mots dans des bases de documents écrits homogènes." Thesis, La Rochelle, 2015. http://www.theses.fr/2015LAROS010/document.
The objective of our thesis is to build an omni-language word retrieval system for scanned documents. We place ourselves in the context where the content of documents is homogenous and the prior knowledge about the document (the language, the writer, the writing style, etc.) is not known. Due to this system, user can freely and intuitively compose his/her query. With the query created by the user, he/she can retrieve words in homogenous documents of any language, without finding an occurrence of the word to search. The key of our proposed system is the invariants, which are writing pieces that frequently appeared in the collection of documents. The invariants can be used in query making process in which the user selects and composes appropriate invariants to make the query. They can be also used as structural descriptor to characterize word images in the retrieval process. We introduce in this thesis our method for automatically extracting invariants from document collection, our evaluation method for evaluating the quality of invariants and invariant’s applications in the query making process as well as in the retrieval process
Cepeda, Eduardo. "Contribution à l'étude probabiliste et numérique des équations homogènes de coagulation - fragmentation." Phd thesis, Université Paris-Est, 2013. http://tel.archives-ouvertes.fr/tel-00833475.
M'Feddal, Hilali. "Brisure de symétrie spatiale dans les systèmes physico-chimiques de non-équilibre: Influence du mode homogène et d'hétérogénéité." Doctoral thesis, Universite Libre de Bruxelles, 1997. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212142.
Combot, Thierry. "Non-intégrabilité algébrique et méromorphe de problèmes de n corps et de potentiels homogènes de degré - 1." Paris 7, 2013. http://www.theses.fr/2013PA077076.
We are searching ail homogeneous potentials of degree — 1 meromorphically intégrable in the Liouville sense. Although a complete classification seems to be still out of reach, we already know several necessary conditions to integrability. Our goal is not only to apply these already existing criterions, but also to create new ones, stronger ones, which would help us to go towards our ultimate goal of complete classification. In this thesis, we are looking for not only rational potentials, but also algebraic potentials, which is necessary as we want our study to include the n body problem. First of all, we define properly what is the associated dynamical System to an algebraic potential in the complex domain, and its integrability. Then, we conclude that the usual criterion of Morales-Ramis-Simo for the meromorphic case still holds. Then we build second order integrability conditions, which are stronger than those already known. Indeed, the Morales-Ramis. Theorem gives us constraints on the second derivative of the potential at a Darboux points, and our criterion take also into account the third order derivatives. In the following, we continue to enhance these integrability criterions in the planar potential case. The integrability conditions at any order can then be computed for any family of potentials, but under a generic condition. Without this generic condition, we compute completely the integrability conditions up to third order, which is, hypothetically, enough to deal with any finite dimensional family of potentials. To conclude, we apply this type of results to the n body problem. The invariance by rotation of such problems lead also to questions about restricted integrability, and we then prove that the n body problem with equal masses is not integrable even in this restricted sense
Gati, Mehdi. "Modélisation, observation et commande de systèmes dynamiques hybrides : application à l'automobile." Paris 11, 2006. http://www.theses.fr/2006PA112052.
In this thesis, we were interested on the modelling and control of hybrid dynamical systems. We study two phenomena that presents this kind of behavior, the jerkiness of vehicle acceleration and the homogeneous combustion. The jerkiness of vehicle acceleration is usually defined as the uncomfortable oscillations of the acceleration that is due to a sharp change on the motor torque. To eliminate theses oscillations we, first, develop a physical model of the vehicle driveline including the mane mechanical components contributing to the phenomenon. The obtained model was piecewise affine because of the backlash present in the powertrain. We applied a model predictive control scheme to deal with such kind of non linearities, and wecompare the closed loop performance to the one of a linear control loop. We also applied techniques of state estimation that we developed in this thesis to the vehicle driveline. The second studied phenomenon was the homogenous combustion. With this type of combustion, the temperature dynamics of gases have a hybrid behaviour. In this thesis we present a reduced model for the homogenous combustion that shown a good correlation with measures. From this model, we derive a second "hybrid" model that is suitable for parameter identification, control and state estimation
Duchereau, Jérôme. "Modélisation non paramétrique des incertitudes en dynamique transitoire des systèmes complexes avec incertitudes non homogènes." Paris, CNAM, 2004. http://www.theses.fr/2004CNAM0479.
This paper is devoted to numerical models for prediction of transient dynamical response induced by shocks upon structures with inhomogeneous random uncertainties. The usual numerical methods for analyzing such structures in the low- and medium- frequency ranges employ reduced matrix models based on the use of the elastic modes. The contribution of the higher modes is very sensitive to the modelling and data errors. Here, a recent nonparametric probabilistic method is applied to construct the random matrix model allowing modelling and data errors to be taken into account. The paper presents an extension of the nonparametric method for the case of inhomogeneous uncertainties in the structures. A dynamic substructuring method is used and every substructure gets its own uncertainty level. Experiments have been developed in order to validate the nonparametric probabilistic approach of random uncertainties for such dynamical systems
Dethier, Jérôme. "Persistance des oscillations homogènes dans les systèmes de réaction-diffusion :analyse stochastique et aspects microscopiques." Doctoral thesis, Universite Libre de Bruxelles, 2001. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211620.
Mestankova, Hana. "Photodégradation du monuron en systèmes homogène et hétérogène en présence de fer et/ou de TiO2 : comparaison et complémentarité." Clermont-Ferrand 2, 2004. http://www.theses.fr/2004CLF21503.
Machet, Corinne. "Première approche de la carbonylation directe de la liaison C-H catalysée par des systèmes hétérobimétalliques." Toulouse, INPT, 1990. http://www.theses.fr/1990INPT028G.
BOTTON, JEAN-FRANCOIS. "Du projet au programme. . . : la medicalisation du systeme d'information hospitalier ; l'experience du c.h.g. de villefranche-sur-saone." Lyon 1, 1992. http://www.theses.fr/1992LYO1M038.