Дисертації з теми "Stabilité en temps petit"
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Saidi, Karima. "Stabilisation d’une classe d’EDP non linéaire. Application à l’équation de Vlasov-Poisson." Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0225.
The work presented in this thesis concerns the stabilization of a class of nonlinear partialdifferential equations. It is a discretized model of the Vlasov-Poisson equation describing the spatial and temporal evolution, in a plasma, of a distribution function of charged particles. In a first step, we addressed the stabilization of the dynamical systems in fixed time (i.e. stabilization in finite time with a uniformly bounded). Criteria relaxing existing results in the literature have been established. Indeed, we have shown that, for a dynamical system, the combination of slow stability (in the polynomial sense) and fast stability (in the finite time sense) leads to a stability in fixed time. Various applications on the discretized Vlasov-Poisson system also concern the double integrator system with observer and the bilinear systems in infinite dimension where for each of these systems, the stabilizing feedback and/or observers in fixed time are constructed and numerically tested. In a second step, we are interested in the small time stabilization of time varying dynamical systems. In fact, the notion of small time is commonly used in theory of controllability. For stabilization, this small time is located between finite time and the fixed time. We have developed theoretical results based on the energy method guaranteeing the disappearance of the solution in small time. This is obtainedby means of a time excitation of a positive function not integrable in the sense of Lebesgue. Then, we have applied our results on model examples such as the transport equation with boundary control, the wave equation subject to a boundary control of the Wentzell type. Also, for finite and infinite dimensional bilinear systems which are, in addition, typical discretized Vlasov-Poisson models. For each system, we have elaborated its feedback whose construction is based on the integration of temporal and uniform excitations
Bui, Van Bien. "La stabilité du filtre non-linéaire en temps continu." Thesis, Nice, 2016. http://www.theses.fr/2016NICE4002/document.
The filtering problem consists of estimating the state of a dynamic, called signal which is often a Markov process, from the noisy observation of the past states. In this thesis, we consider a filtering model in continuous time for the diffusion process. The aim is to study the stability of the optimal filter with respect to its initial condition beyond the mixing (or quasi – mixing) hypothesis for the transition kernel
Bhiri, Bassem. "Stabilité et stabilisation en temps fini des systèmes dynamiques." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0100/document.
This dissertation deals with the finite time stability and the finite time stabilization of dynamic systems. Indeed, it is often important to ensure that during the transient regime, the state trajectories do not exceed certain predefined limits in order to avoid saturations and excitations of the nonlinearities of the system. Hence the interest is to study the stability of the dynamic system in finite time. A dynamic system is said to be stable in finite time (FTS) if, for any initial state belonging to a predetermined bounded set, the state trajectory remains within another predetermined bounded set for a finite and fixed time. When the system is disturbed, it is called finite time boundedness (FTB). In this manuscript, the goal is to improve the results of finite time stability used in the literature. First, new sufficient conditions expressed in terms of LMIs for the synthesis of an FTB controller by dynamic output feedback have been developed via an original descriptor approach. An original method has been proposed which consists in using a particular congruence transformation. Second, new LMI conditions for the study of finite time stability and finite time stabilization have been proposed for disturbed and undisturbed nonlinear quadratic systems. Third, to obtain even less conservative conditions, new developments have been proposed using polynomial Lyapunov functions
Bhiri, Bassem. "Stabilité et stabilisation en temps fini des systèmes dynamiques." Electronic Thesis or Diss., Université de Lorraine, 2017. http://www.theses.fr/2017LORR0100.
This dissertation deals with the finite time stability and the finite time stabilization of dynamic systems. Indeed, it is often important to ensure that during the transient regime, the state trajectories do not exceed certain predefined limits in order to avoid saturations and excitations of the nonlinearities of the system. Hence the interest is to study the stability of the dynamic system in finite time. A dynamic system is said to be stable in finite time (FTS) if, for any initial state belonging to a predetermined bounded set, the state trajectory remains within another predetermined bounded set for a finite and fixed time. When the system is disturbed, it is called finite time boundedness (FTB). In this manuscript, the goal is to improve the results of finite time stability used in the literature. First, new sufficient conditions expressed in terms of LMIs for the synthesis of an FTB controller by dynamic output feedback have been developed via an original descriptor approach. An original method has been proposed which consists in using a particular congruence transformation. Second, new LMI conditions for the study of finite time stability and finite time stabilization have been proposed for disturbed and undisturbed nonlinear quadratic systems. Third, to obtain even less conservative conditions, new developments have been proposed using polynomial Lyapunov functions
Vidalon, Isabelle Hennequin Jacques. "Letemps dans les romans comiques du XVIIème siècles (Sorel, Tristan L'Hermite, Scarron, Furetière, Claude Le Petit) /." [S.l.] : [s.n.], 1997. ftp://ftp.scd.univ-metz.fr/pub/Theses/1997/Vidalon.Isabelle.LMZ9720.pdf.
Amini, Hadis. "Stabilisation des systèmes quantiques à temps discrets et stabilité des filtres quantiques à temps continus." Phd thesis, Ecole Nationale Supérieure des Mines de Paris, 2012. http://pastel.archives-ouvertes.fr/pastel-00803170.
Sainte-Rose, Raymond. "Temps et structure dans la psychanalyse d'un enfant. (le cas du petit hans)." Toulouse 2, 1991. http://www.theses.fr/1991TOU20006.
"time and structure of a child's psychoanalysis" is a psychanalytical thesis. It refutes the idea of a chronology in the genesis in the object-relation. S. Freud did not approach the question of time in psychoanalysis in this way. On the other hand, j. Lacan put forward the idea of the importance of the time question in the relation between time and structure. This last perspective has been choosen. In the case of hans (freud (s. ). Standart edition, x, 116. ) it is shown that the true fondations to the temporality of the subject are to be found in the lack in the structure itself. Thus a new understanding towards the treatment of a child by psycholoanalysis
Zoghlami, Naïm. "Stabilité et stabilisation en temps fini des ystèmes dynamiques interconnectés et problème de consensus en temps fini." Thesis, Evry-Val d'Essonne, 2014. http://www.theses.fr/2014EVRY0023/document.
This manuscript is dedicated to the study of finite time stability and stabilization of interconnected dynamical systems and finite time consensus problem. After a general introduction, the first part of this thesis focuses on finite time stability and stabilization of perturbed systems and interconnected systems. The second part of this thesis is devoted to the problems of: finite-time consensus, average consensus and finite time stabilization of multi-agent systems. This concept has been addressed by targeting non-linear controlled dynamical systems: with and without drift term. Some protocols are proposed to solve the finite time consensus problem. Many applications and simulations are illustrated
Convert, Laurence. "Système microfluidique d'analyse sanguine en temps réel pour l'imagerie moléculaire chez le petit animal." Thèse, Université de Sherbrooke, 2012. http://hdl.handle.net/11143/6623.
Garnero, Marie-Agnès. "Commande adaptative à petit pas de temps : Théorie et application sur un four électrique." Ecully, Ecole centrale de Lyon, 1990. http://www.theses.fr/1990ECDL0030.
Mesnager, Laurent. "Estimation en temps petit de densités conditionnelles dans des problèmes de filtrage non linéaire." Paris 11, 1996. http://www.theses.fr/1996PA112243.
Dauphin, Gabriel. "Application des représentations diffusives à temps discret." Phd thesis, Télécom ParisTech, 2001. http://tel.archives-ouvertes.fr/tel-00005780.
Le première partie consiste en la mise en place des représentations diffusives à temps discret. Certains filtres non-relationnels, notamment les différences frationnaires, sont une agrégation continue de dynamiques purement amorties. Les représentations diffusives s'appliquent à toutes les discrétisations de l'intégration fractionnaire y compris celles pour lesquelles la fonction de transfert n'est pas connue analytiquement. Les filtres diffusifs peuvent être réalisés par un système de dimension infinie. Cette structure est un cadre adapté à l'approximation par un filtre relationnel, à l'analyse asymptotique aux temps longs et à l'élaboration d'un critère de dissipativité.
La deuxième partie consiste à appliquer ces outils pour l'étude des couplages formés de filtres diffusifs et de filtres rationnels positifs. L'application d'un critère de Nyquist prouve la stabilité énergétique. Ces couplages sont en fait la somme d'une partie entière et d'une partie diffusive, ce résultat de décomposition montre que certains couplages sont stables EBSB (entrée-bornée, sortie-bornée). La dissipativité de la réalisation diffusive ainsi que le lemme de Kalman-Yacubovich-Popov montrent notamment la stabilité interne de ces couplages ; une démonstration originale du caractère asymptotique de la stabilité interne est ainsi proposée. Les approches utilisées pour prouver ces stabiblités permettent une analyse asymptotique aux temps longs.
Farhat, Hassan. "Prise en compte des temps et des déplacements en stabilité des pentes." Lyon, INSA, 1990. http://www.theses.fr/1990ISAL0092.
[The aim of this work LS to propose new methods of calculation in slope stability analysis. First, a bibliographical review, on shear behaviour of soils and methods of slope stability analysis, shows the advantage of a displacement formulation. Then, two methods of calculation were proposed. The first takes into account the displacements measured by inclinometers to follow the evolution of a slope. The second method is more general. It permits one to follow the evolution of a slope (stresses and displacements) as a function of the varying boundary conditions. Laws of creep are introduced in the model. The displacement of the slope with time can be controlled. The two methods are validated by comparing the results of the calculation with the sliding measurements of the experimental embankment of Sallèdes (Puy de Dôme) and the sliding of Campagna (Italy). ]
Agulhari, Cristiano Marcos. "Stabilité et commande des systèmes linéaires variant dans le temps aux paramètres incertains." Phd thesis, INSA de Toulouse, 2013. http://tel.archives-ouvertes.fr/tel-00822689.
Sarmis, Merdan. "Etude de l'activité neuronale : optimisation du temps de simulation et stabilité des modèles." Thesis, Mulhouse, 2013. http://www.theses.fr/2013MULH3848/document.
Computational Neuroscience consists in studying the nervous system through modeling and simulation. It is to characterize the laws of biology by using mathematical models integrating all known experimental data. From a practical point of view, the more realistic the model, the largest the required computational resources. The issue of complexity and accuracy is a well known problem in the modeling and identification of models. The research conducted in this thesis aims at improving the simulation of mathematical models representing the physical and chemical behavior of synaptic receptors. Models of synaptic receptors are described by ordinary differential equations (ODE), and are resolved with numerical procedures. In order to optimize the performance of the simulations, I have implemented various ODE numerical resolution methods. To facilitate the selection of the best solver, a method, requiring a minimum amount of information, has been proposed. This method allows choosing the best solver in order to optimize the simulation. The method demonstrates that the dynamic of a model has greater influence on the solver performances than the kinetic scheme of the model. In addition, to characterize pathogenic behavior, a parameter optimization is performed. However, some parameter values lead to unstable models. A stability study allowed for determining the stability of the models with parameters provided by the literature, but also to trace the stability constraints depending to these parameters. Compliance with these constraints ensures the stability of the models studied during the optimization phase, and therefore the success of the procedure to study pathogen models
Vidalon, Isabelle. "Le temps dans les romans comiques du XVIIème siècles : (Sorel, Tristan L'Hermite, Scarron, Furetière, Claude Le Petit)." Metz, 1997. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1997/Vidalon.Isabelle.LMZ9720.pdf.
Unlike pastoral and heroic novels, 17th century comedy stories aim to be more realistic and offer a different conception of temporality. We have highlighted the stages indicating a progression which goes from the denunciation of temporality (that of heroic novels in "le Roman bourgeois" by Furetière) to the search for a mediocre temporality, which doesn't quite reject imaginativeness ("L'heure du berger" by Claude Le Petit. This imaginativeness interlaces with other times so intricately as to give the reader a feeling of dizziness. Thus, the works studied ("Francion", "Le berger extravagant" by Sorel, "Le page disgracié" by Tristan l'Hermitte, "Le roman comique" by Scarron) are close to baroque aesthetism in the movement that gives them live, in their open structure, but "Polyandre" by Sorel opens up another path, by showing how the comedy story leans towards the social novel
Dauphin, Gabriel. "Application des représentations diffusives au temps discret." Paris, ENST, 2001. https://pastel.archives-ouvertes.fr/tel-00005780.
Yao, Jingchen. "Temporalité et causalité : le cas de "alors" dans "Le Petit Prince"." Thesis, Paris, EHESS, 2019. http://www.theses.fr/2019EHES0005.
The objective of this thesis is to study the questions of “temporality” and “causality” which are related to the use of alors in The Little Prince. After having reviewed the main analyzes given to this word, we show that the referential approach, mainly adopted by these analyzes, presents flaws in order to account for the linguistic phenomena traditionally considered “temporal” and “causal” concerning the uses of alors. As an alternative solution, we take an argumentative perspective by choosing as the theoretical framework the Semantic Blocks Theory (TBS) developed by Carel in the 90s. This theory is not interested in the question of the truth-conditions, and it proposes to describe the meaning of the utterances by an argumentative sequence (of which the two segments are connected by conjunctions such as donc, par conséquent, si, de ce fait, etc., or by conjunctions such as même si, cependant, pourtant, bien que, etc.) and by an aspect concretized by this sequence. Thus, by using the technical tools provided by the TBS, we identify four uses of alors : the “contextuel” use, the “semi-causal” use, the “détaillant” use and the “articulateur” use. In addition, we also question the origin of the “causality” and “temporality” senses which have been attached to certain uses of alors. According to us, the sense of “causality” attributed to some alors is due to the unit between the concatenation and the aspect concretized by this sequence. The sense of “temporality”, for its part, is related to the notion of “discordant concordance” which characterizes, according to Aristotle, the composition of the plot. These reflections allow us to overcome the opposition causality / temporality which traditionally characterizes the employment of alors, and to show, on the one hand, that the fundamental value of the use of the alors is not referential but argumentative, and other on the other hand, this word actively participates in the determination of the meaning of a statement
Moulay, Emmanuel. "Une contribution à l'étude de la stabilité en temps fini et de la stabilisation." Phd thesis, Ecole Centrale de Lille, 2005. http://tel.archives-ouvertes.fr/tel-00114333.
La deuxième partie de ce mémoire est consacrée à la stabilisation en utilisant les fonctions de Lyapunov contrôlées. Une large part est dédiée à la stabilisation en temps fini.
Taousser, Fatima Zohra. "Analyse de stabilité des systèmes à commutations sur un domaine de temps non-uniforme." Thesis, Valenciennes, 2015. http://www.theses.fr/2015VALE0038/document.
This thesis deals with the stability analysis of switched systems that evolve on non uniform time domain by introducing the time scale theory. We are interested mainly in dynamical linear switched systems defined on particular time scale T = P{tσk ,tk+1} = ∪∞k=0[tσk, tk+1]. The studied system switches between a continuous-time dynamical subsystem on the intervals ∪∞k=0[tσk, tk+1[ and a discrete-time dynamical subsystem on instants ∪∞k=0{tk+1} (a discrete time) with a time-varying discrete step. In a first part, sufficient conditions are given to guarantee the exponential stability of this class of switched systems. Then necessary and sufficient conditions for stability are given by determining a region of exponential stability. In the second part, the stability of this class of switched systems with nonlinear uncertainties, is treated using majoration of the solution, and after that by introducing the approach of a common Lyapunov function. The third part is devoted to the consensus problem under intermittent information transmissions where the closed-loop multi-agent system can be represented as a switched system using a combination of linear continuous-time and linear discrete-time systems
Bahtiti, Mohamed. "Fibrés vectoriels algébriques de petit rang sur la variété projective P^n." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066076/document.
1 - Generalization of the special instanton bundles on P^2n+1 which is called the (b+1)-weighted instanton bundles on P^2n+1. The stability of these vector bundles was studied in the case b=0. We studied the deformation of weighted Steiner bundles on P^2n+1. 2 - Generalization of the Tango bundles on P^n which is called the weighted Tango bundles on P^n. The stability of these vector bundles has been studied. The deformation of these vector bundles has been studied. 3 - Construction of vector bundles of rank 3 on P^4. We have studied the condition to have vector bundles that do not isomorphic to a direct sum of three line bundles
Kabakouala, André Bernard. "Comportement en temps long de quelques EDPs dispersives." Thesis, Tours, 2018. http://www.theses.fr/2018TOUR4001/document.
No summary available
Zhang, Hui-Long. "Développement en temps petit de la solution de l'équation de Zakai͏̈ et résolution numérique par maillage adaptatif." Aix-Marseille 1, 1992. http://www.theses.fr/1992AIX11033.
Barrere, Sophie. "Le grotesque : petit traité anarchique sur les oeuvres d'art." Thesis, Montpellier 3, 2011. http://www.theses.fr/2011MON30065/document.
Without regard to chronology or category, this research addresses the Art under the lens of the ludicrousness, revealing a crossing of intimacy to the universal that inhabits them. This starts with a crossing beyond the senses, taken in the space of language and its determinants. Ludicrousness brings the systematic contradiction and movement semantic, a breakaway. The Art works from and beyond the illusion of the senses to create the common, through the story. Vigilance to the "do" plastic reveals the powers that work on the artist's body and involve rhythm, reversal and instant, where beyond the visible articulated the show, where the creation is described as a vital commitment to this point of impossible around which decides the brush stroke, the act of register. In this understanding, the artwork is an operating surplus, a break from reality which origin the story. Psychoanalytic reflections deepen the stake of this registration, which the transference phenomenon reactive the subtlety of the process of identification. This opens up the ethical pace, where it comes to the space occupied, an alternation of life, death, whose body bears the secular debt as archetypal sense of living together. This process of identification reactivated revives the subject facing its lack of being, castrated, fateful, caught in this cycle of temporality that precedes and exceeds him, face to this big Other, this "at least one" that escapes. Here's a temporal thought on the significance of symbolism which people our images unconsciously and independently of the pathological and create this sharing of intimacy to the universal
Flouzat, Christophe. "Modulateurs sigma-delta passe-bande en temps continu." Paris 11, 2003. http://www.theses.fr/2003PA112339.
Shen, Dawei. "Problèmes de stabilité en relativité générale." Electronic Thesis or Diss., Sorbonne université, 2024. http://www.theses.fr/2024SORUS014.
This thesis is devoted to study the stability of particular solutions to Einstein vacuum equations: the Minkowski spacetime and Kerr black holes. More precisely, this thesis contains four main results. The first result concerns the stability of Minkowski spacetime outside an outgoing null cone and contains a generalization of the result of Klainerman-Nicolo. The second result shows the global nonlinear stability of the Minkowski space under the assumption of minimal decay on the initial data generalizing a result of Bieri. The third result provides a new proof of Kerr stability in external regions, obtained by Caciotta-Nicolo. The common feature of these three works is the application of the r^p-weighted estimate method introduced by Dafermos-Rodnianski, as an alternative to the vectorfield method, to obtain control of the curvature terms. The last result provides a construction of GCM hypersurfaces, which is a part of a sequence of five works (the four others are due to Klainerman-Szeftel and Giorgi-Klainerman-Szeftel) establishing Kerr stability for small angular momentum
Freytes, Julian. "Analyse de stabilité en petit signaux des Convertisseurs Modulaires Multiniveaux et application à l’étude d'interopérabilité des MMC dans les Réseaux HVDC." Thesis, Ecole centrale de Lille, 2017. http://www.theses.fr/2017ECLI0022/document.
This thesis deals with the modeling and control of MMCs in the context of MTDC. The first objective is to obtain an MMC model in dq frame which can reproduce accurately the AC- and DC- interactions, while representing at the same time the internal dynamics which may interact with the rest of the system. This model is suitable to be linearized and to study its stability, among other linear techniques. Then, based on the developed dq model, different control strategies are developed based on the state-of-the-art on MMC controllers. Since the order of the system may be a limiting factor for studying MTDC grids with many MMCs, different reduced-order models are presented and compared with the detailed dq model. Finally, the developed MMC models with different controllers are used for the MTDC studies. The impact of the chosen controllers of each MMC is evaluated, highlighting the potential issues that may occur in multivendor schemes
Toldo, Sandrine. "Convergence de filtrations ; application à la discrétisation de processus et à la stabilité de temps d'arrêt." Phd thesis, Université Rennes 1, 2005. http://tel.archives-ouvertes.fr/tel-00011277.
Fedelich, Bernard. "Trajets d'équilibre des systèmes mécaniques dissipatifs à comportement indépendant du temps physique." Marne-la-vallée, ENPC, 1990. http://www.theses.fr/1990ENPC9018.
Wang, Hongchen. "Imagerie quantitative du dépôt d’aérosols dans les voies aériennes du petit animal par résonance magnétique." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112034/document.
This PhD thesis is part of the OxHelease project (ANR-TecSan 2011) that aims to study the impact of helium-oxygen inhalation on ventilation, blood oxygenation, and aerosol deposition in chronic obstructive respiratory diseases, such as asthma and emphysema. In this context, this work consisted of developing magnetic resonance imaging methods to quantify aerosol deposition in rat lung.The inhalation of pharmaceutical aerosols is an attractive approach for the treatment of lung diseases such as chronic obstructive pulmonary diseases. This is also an interesting route for the treatment of systemic disorders with the potentially fast drug transfer into circulation. However, the transport and the deposition of particles within the lungs are complex and difficult to predict, since deposition patterns depend on a number of parameters, such as administration protocols, airway geometries, inhalation patterns, and gas and aerosol aerodynamic properties. Thus, understanding drug delivery through the lungs requires imaging methods to quantify particle deposition. MRI is less conventional than other approaches for lung characterization, but the technical advances and the multiple contrast mechanisms render lung imaging more feasible.To obtain exploitable signal from the lung parenchyma of the rat, an ultra-short echo (UTE) sequence was implemented on a 1.5 T clinical system. This technique was combined with a Gadolinium-based aerosol nebulization of short duration in spontaneously breathing rats. The main contrast mechanism used here is the modification of the longitudinal relaxation time yielding signal enhancement and allowing to assess the local concentration with a spatial resolution of (0.5 mm)3 and a temporal resolution of 7.5 min enabling to quantitatively follow up lung clearance. The sensitivity of this approach (with a detection limit close to 20 µM) was determined. To do so several specific processing methods were developed for local and total lung evaluation, including segmentation, distribution analysis and statistics. After validation in the healthy rats, for which a signal enhancement of 50% on average, a homogenous distribution of deposition and a relatively low total deposited dose (~1 µmol/kg body weight) were observed, this imaging modality could be applied in asthmatic and emphysematous animal models. Significant differences were obtained such as homogeneity of deposition or clearance. Moreover, preliminary results of a multimodal study, in which MRI was compared with computed tomography and with nuclear medicine imaging in the same animals, were obtained. Finally, in order to evaluate the feasibility of other potential quantitative MRI approaches, a dual-nuclei proton/fluorine system was implemented and tested in rats for determining the sensitivity of fluorine-based gas and aerosol imaging.These MRI strategies may be applied for the in vivo characterization of particle deposition inhaled under variable administration conditions. Their sensitivity suggests a feasible translation to human
Cavichioli, Gonzaga Carlos. "Analyse de stabilité et de performances d'une classe de systèmes non-linéaires à commutations en temps discret." Phd thesis, Université de Lorraine, 2012. http://tel.archives-ouvertes.fr/tel-00762873.
Cavichioli, Gonzaga Carlos Alberto. "Analyse de stabilité et de performance d'une classe de systèmes non-linéaires à commutations en temps discret." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0086/document.
In this PhD thesis, several problems of stability analysis and control design of discrete-time switched nonlinear systems are addressed. As main contribution, a new class of Lyapunov functions which takes the nonlinearity into account has been proposed. We show that these functions are suitable to solve the classical stability analysis problem of linear systems connected to a cone bounded nonlinearity. Instead of the original Lyapunov Lur'e function, the assumptions about the nonlinearity variation are not required. Furthermore, the local stability analysis and control synthesis problems of Lur'e systems subject to control saturation are tackled by considering the level set of our function as an estimate of the basin of attraction. We expose that this estimate, which is given by non-convex and disconnected sets, is less conservative than ellipsoidal sets. We extend these results in order to deal with the problems of stability analysis and stabilization of discrete-time switched nonlinear systems. On one hand, we consider the case of arbitrary switching such that our sufficient conditions assure the properties of stability for all possible switching rules. In this framework, we highlight that our function is able to provide a suitable estimate of the basin of attraction. On the other hand, we tackle the problem of switching rule design aiming at the stabilization of discrete-time switched systems with nonlinear modes. We propose a switching strategy depending on the minimum of our switched Lyapunov Lur'e function. Hence, our framework leads to state space partitions, related to the mode activation, which are not restricted to conic sets, commonly exhibited by the switched quadratic functions approaches
Cavichioli, Gonzaga Carlos Alberto. "Analyse de stabilité et de performance d'une classe de systèmes non-linéaires à commutations en temps discret." Electronic Thesis or Diss., Université de Lorraine, 2012. http://www.theses.fr/2012LORR0086.
In this PhD thesis, several problems of stability analysis and control design of discrete-time switched nonlinear systems are addressed. As main contribution, a new class of Lyapunov functions which takes the nonlinearity into account has been proposed. We show that these functions are suitable to solve the classical stability analysis problem of linear systems connected to a cone bounded nonlinearity. Instead of the original Lyapunov Lur'e function, the assumptions about the nonlinearity variation are not required. Furthermore, the local stability analysis and control synthesis problems of Lur'e systems subject to control saturation are tackled by considering the level set of our function as an estimate of the basin of attraction. We expose that this estimate, which is given by non-convex and disconnected sets, is less conservative than ellipsoidal sets. We extend these results in order to deal with the problems of stability analysis and stabilization of discrete-time switched nonlinear systems. On one hand, we consider the case of arbitrary switching such that our sufficient conditions assure the properties of stability for all possible switching rules. In this framework, we highlight that our function is able to provide a suitable estimate of the basin of attraction. On the other hand, we tackle the problem of switching rule design aiming at the stabilization of discrete-time switched systems with nonlinear modes. We propose a switching strategy depending on the minimum of our switched Lyapunov Lur'e function. Hence, our framework leads to state space partitions, related to the mode activation, which are not restricted to conic sets, commonly exhibited by the switched quadratic functions approaches
Rhim, Achour. "Prévision du temps de vie du lien pour améliorer la stabilité de routage dans les réseaux Ad hoc." Mémoire, École de technologie supérieure, 2009. http://espace.etsmtl.ca/77/1/RHIM_Achour.pdf.
Roncali, Emilie Liliane Catherine. "Développements en imagerie de luminescence in vivo chez le petit animal : système d'acquisition sur animal vigile et tomographie en temps réel." Châtenay-Malabry, Ecole centrale de Paris, 2008. http://www.theses.fr/2008ECAP1071.
Small animal imaging is a powerful tool largely used in preclinical studies. Luminescence-based techniques allow an external detection of light from visible or infrared spectrum and constitute a rapidly expanding field. These innovative techniques are still under development and the field of applications could be extended. This work consists in two projects that were conducted in order to bring about some solutions to these issues. A first development was based on the real time capacity of luminescence imaging. Because of their sensitivity, cooled CCD cameras are largely used to detect the very small amount of light produced by bioluminescence reactions or by fluorescence probes. However, these systems generally require an exposure time of several seconds to overcome the readout noise. We report here the development and the validation of a photon counting-based system combined with a video monitoring function. The biological signal of interest, recorded by a third generation cooled intensified CCD camera, is spatially and temporally registered with the tracking video. Performing molecular imaging studies without the use of anaesthetics and in freely moving animals would limit the interference with signalization processes. Another aspect of luminescence imaging improvements was investigated in this thesis. A major limitation of this technique is the lack of quantification in planar imaging. Most of current systems are not compatible with real time imaging because of their acquisition process. We designed and realized an innovative device based on the use of a conical mirror enclosing the sample and thus allowing to record an anamorphic image of the sample
Cilas, Christian. "Stabilité des caractères dans le temps chez les plantes pérennes : étude génétique de la capacité productive chez Coffea spp." Paris 11, 2004. http://www.theses.fr/2004PA112032.
With perennial plants, the efficiency of genetic improvement is limited by particular constraints associated with the economic life span of the crops. Although ways of estimating genetic parameters have been improved, the characters on which analyses are based do not always have a very precise biological sense. For exemple, when considering fruits or seeds, as in the case of coffee trees, how many years of observations does it take to define the "production" character? How can variations in characters over time be integrated with a view to defining a breeding objective in which frequent reference is made to stability and sustainability. After an initial section characterizing competition between fruit production and vegetative growth, two complementary approaches have been taken to try and answer these questions. The first consisted in analysing different trials and mating designs for the species Coffea arabica and Coffea canephora. The particularity of those trials, notably for C. Canephora, lay in the way they were monitored, over a large number of years (14 years). It was found that first cycle production (before coffee trees are cut back for the first time) was not always sufficient for predicting the production of the following cycles. In addition, indexes are proposed for characterizing how planting material distributes its annual yields over time. The second approach consisted in identifying architectural characters able to predict the production capacity of the coffee trees. Thus, the squat coffee trees, with short inter nodes, constitute the morphotypes to be promoted
Altazin, Estelle. "Stabilité et replanification d’un système ferroviaire dense." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEM008.
While operating a dense railway system, minor incidents can easily generate delays. Those delays can spread and rapidly amplify along one line, and sometimes to other lines sharing the infrastructure, rolling-stock units or drivers. This thesis addresses the real-time decision-making problem while operating a dense railway system. Dense railway operations are first presented, along with their properties and weaknesses. The notion of stability for a dense railway system is introduced and discussed. Related problems and approaches of the literature are reviewed, both in railway and in urban transportation, and the considered real-time rescheduling problem is presented. A first resolution approach, based on an Integer Linear Programming model, is proposed, and numerical experiments on real data are analyzed. They show the relevance of the rescheduling problem. A more general approach is then proposed, that iterates between an optimization module and a simulation module. All operational actions are considered in the iterative approach, and the use of simulation allows for a precise evaluation of the impact of actions on passengers. This new approach is also multi-objective, thus different solutions can be proposed to the decision makers. A rescheduling tool has been implemented, using the iterative approach, and connected to industrial data flows. Real-life experiments on a Transilien line proved that the tool, and thus the iterative approach, fulfills the decision makers’ expectations and helps reducing the duration of perturbations and their impact on passengers
Boucher, Marie-Christine. "Impact des traitements physiques sur la stabilité des matrices d'encapsulation à base d'isolat de protéines de lactosérum et de pectine faiblement méthylée." Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24290/24290.pdf.
Michel, Patrice. "Estimation en temps réel des modes souples des voilures de grande dimension." Toulouse, INPT, 2003. http://www.theses.fr/2003INPT059H.
In the aeronautics, the vibrations of an aerofoil can create a critical problem of stability. Aerofoils can even destroy the structure of the plane or simply reduce the quality of the flight. They can also have as a consequence the excitation of badly damped modes which can reduce the performance of laws of orders (based on a rigid model of the plane modifiyng its global dynamics). No long time ago, the rigidity of the aerofoils ensured a frequential decoupling between the structural modes and the piloting modes. Technico-economic constraints lead the aeronautical manufacturers to develop light planes of great scale. Thus, the design of large planes with flexible structure resulted in having these two sets of modes at similar frequencies. In such a context, it becomes difficult to separate the different modes without limiting the maneuvrability of the plane. As a consequence, alternative solutions have be studied. The objective of this thesis is to propose a real time algorithm able to estimate frequencies, amplitudes and possibly the phases of modes with the requirements related to embarked calculation under industrial constraints
Bernuau, Emmanuel. "Robustesse et stabilité des systèmes non-linéaires : un point de vue basé sur l'homogénéité." Phd thesis, Ecole Centrale de Lille, 2013. http://tel.archives-ouvertes.fr/tel-00917798.
Adjizian-Gérard, Jocelyne. "La variabilite spatiale des pluies dans le petit bassin versant du ringelbach (hautes-vosges) : effet de la topographie et des types de temps." Université Louis Pasteur (Strasbourg) (1971-2008), 1994. http://www.theses.fr/1994STR10001.
The purpose of this study is to understand better the spatial rainfall characteristics in a small watershed: wind modifying raindrops trajectory, the aerodynamical effect is the first responsible factor, the winfield depends on weather types which define its main characteristics (regional direction and speed) and on topography which determines its spatail structure. This study shows the topography local wind interaction effect, according to weather types, on rainfall repartition in mountainous area. Therefore, we worked according to: - a spatial scale of an elementary watershed: the ringelbach (36 ha). -a temporal scale of a rainy period. The treatment results of a sample of 59 rainy period show that rainfall collected by standard horizontal raingauges ("meteorological" point rainfall) differs largely from the amount of water actually intercepted by the sloping ground ("hydrological" point rainfall). Different parameters have been outlined. They are related to: -pluviometrical metrology (important aspect of pluviometry) -topographic interaction local wind. The "hydrological" rainfall in this watershed has an average of 5 to 8% above the "meteorological" rainfall. A trigonometrical model which takes into account topographical parameters, permits an estimation of the point rainfall vector on a slope, from measurements made at a same site with 3 differently tited rainguages where 14 sites have been equipped with such set of 3 raingauges. It permits an explanation of the large differences observed between "meteorological and "hydrological" point rainfall within the catchment
Ariba, Yassine. "Sur la stabilité des systèmes à retards variant dans le temps : théorie et application au contrôle de congestion d'un routeur." Phd thesis, Université Paul Sabatier - Toulouse III, 2009. http://tel.archives-ouvertes.fr/tel-00442454.
Petit, Gérard. "Observations VLBI des pulsars millisecondes pour le raccordement des systèmes de référence célestes et la stabilité des échelles de temps." Observatoire de Paris, 1994. https://hal.science/tel-02095454.
Bouazza, Kheir-Eddine. "Commande basée sur des observateurs pour les systèmes non-linéaires en temps discret." Nancy 1, 2004. http://www.theses.fr/2004NAN10171.
Research activities presented in this thesis concerne the stabilisation, with obserber-based controllers, of discrete-time nonlinear systems. The approach which we proposed doesn't require a particular structure of the output contrary to the methods based on the the passivity theory. Unlike the jurdjevic-quinn method, it doesn't need the stability of the free dynamics. A lyapunov function common to a great number of systems is used for the analysis of stability. Moreover it has the advantage of being simply implementable. Using the results established previously, synthesis of a control law based on an extended kalman observer was given. The third section presents an observer based controller which stabilizes globally exponentially a class of nonlinear systems. An extension to delay systems was established. In the last section, we present a simple conditions in linear matrix inequalities form, which stbilizes asymptotically a large class of delay nonlinear systems. Some other conditions allowing the synthesis of observers for different classes of nonlinear systems were presented
Bernuau, Emmanuel. "Robustesse et stabilité des systèmes non-linéaires : un point de vue basé sur l’homogénéité." Thesis, Ecole centrale de Lille, 2013. http://www.theses.fr/2013ECLI0015/document.
The purpose of this work is the study of stability and robustness properties of nonlinear systems using homogeneity-based methods. Firstly, we recall the usual context of homogeneous systems as well as their main features. The sequel of this work extends the homogenization of nonlinear systems, which was already defined in the framework of weighted homogeneity, to the more general setting of the geometric homogeneity. The main approximation results are extended. Then we develop a theoretical framework for defining homogeneity of discontinuous systems and/or systems given by a differential inclusion. We show that the well-known properties of homogeneous systems persist in this context. This work is continued by a study of the robustness properties of homogeneous or homogenizable systems. We show that under mild assumptions, these systems are input-to-state stable. Finally, the last part of this work consists in the study of the example of the double integrator system. We synthesize a finite-time stabilizing output feedback, which is shown to be robust with respect to perturbations or discretization by using techniques developed before. Simulations conclude the theoretical study of this system and illustrate its behavior
Ben, Rejeb Jihene. "Analyse de stabilité et synchronisation des systèmes singulièrement perturbés." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0117/document.
This PhD thesis is dedicated to the study of stability and control design for singularly perturbed systems. In the first part, we introduce and analyze a general class of singularly perturbed linear hybrid systems, in which the slow or fast nature of the variables is mode-dependent. Our stability analysis is based on classical results of Lyapunov’s theory for singularly perturbed systems. A second part of this work presents the design of a decentralized control strategy that allows singularly perturbed multi-agent systems to achieve synchronization with global performance guarantees. To avoid the use of centralized information related to the interconnection network structure, the problem is solved by rewriting the synchronization problem in terms of stabilization of a singularly perturbed uncertain linear system
Sainlaud, Chloé. "Caractérisation du veillissement de matrices alimentaires enrichies à base lipidique. Etude de l'évolution de leurs propriétés texturales au cours du temps." Thesis, Normandie, 2021. http://www.theses.fr/2021NORMR009.
The objective of this work was to determine the origin of textural modifications observed during the storage of a food product, the product Plumpy’Nut®. It is a complex matrix composed of crystalline, amorphous, liquid and vitreous constituents. Its composition gives it the particularity of containing at room temperature, a fraction in the liquid state and a fraction in the solid state. A first global analysis allowed to identify two ingredients which are driving mainly the structure and thermal behavior of the product and, by extension, its rheological properties. These two ingredients are palm oil and an element called “stabilizer” (blend of fully hydrogenated fat, monoand diglycerides). Crystallization mechanisms of these two constituents were studied by means of X-Ray scattering and diffraction analyses, with a particular interest in the roles of cooling kinetics. We showed that palm oil crystallizes mainly under polymorphic form β’ and that adding the “stabilizer” induces a crystallization partially under the most stable polymorphic form β, no matter the cooling profile considered. The stabilizer initiates a crystallisation of palm oil at higher temperature compared to palm oil alone (around 35°C instead of 25°C). The lamellar configuration adopted by triglycerides depends on the cooling profile considered. From a rheological point of view, the viscosity evolution of the product Plumpy’Nut® versus temperature is well correlated with the crystallization dynamics of Palm oil-Stabilizer blend. The aging of the product Plumpy’Nut® considering several storage and processing conditions, was studied during 26 months by means of several physical-chemical analyses. The origin of the gradual increase of the products firmness over time depends mainly on storage temperature. At low temperature (5°C), post-crystallization phenomenon of lipids dominates while at higher temperature (40°C), the chemical aging and oil rising predominate
Ducros, Florence. "Maintien en conditions opérationnelles pour une flotte de véhicules : étude de la non stabilité des flux de rechange dans le temps." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS213/document.
This thesis gathers methodologicals contributions to simulate the need of replacement equipment for a vehile fleet. Systems degrade with age or use, and fail when they do not fulfill their mission. The user needs an assurance that the system is operational during its useful life. A support contract obliges the manufacturer to remedy a failure and to keep the system in operational condition for the duration of the MCO contract.The management of support contracts or the extension of support requires knowledge of the equipment lifetime and also the uses condition of vehicles, which depends on the customer. The analysis of customer returns or RetEx is then an important tool to help support the decision of the industrial. In reliability or warranty analysis, engineers must often deal with lifetimes data that are non-homogeneous. Most of the time, this variability is unobserved but has to be taken into account for reliability or warranty cost analysis.A further problem is that in reliability analysis, the data is heavily censored which makes estimations more difficult. We propose to consider the heterogeneity of lifetimes by a mixture and competition model of two Weibull laws. Unfortunately, the performance of classical estimation methods (maximum of likelihood via EM, Bayes approach via MCMC) is jeopardized due to the high number of parameters and the heavy censoring.To overcome the problem of heavy censoring for Weibull mixture parameters estimation, we propose a Bayesian bootstrap method, called Bayesian RestorationMaximization.We use an unsupervised clustering method to identify the profiles of vehicle uses. Our method allows to simulate the needs of spare parts for a vehicles fleet for the duration of the contract or for a contract extension
Laget, Michaël. "Stabilité d'éléments superlourds au voisinage de Z=120 testée par l'étude de leurs temps de fission déduits par la méthode du blocage cristallin." Paris 11, 2007. http://www.theses.fr/2007PA112234.
Rigault, Cyril. "Etude mathématique de modèles cinétiques pour la gravitation, tenant compte d'effets relativistes : stabilité, solutions autosimilaires." Phd thesis, Université Rennes 1, 2012. http://tel.archives-ouvertes.fr/tel-00787487.