Tratamos o problema do planejamento periódico de trajetórias: fixados uma trajetória periódica de um sistema afim sem arrasto em um grupo de Lie compacto e conexo G e uma condição inicial em G, encontrar outra trajetória do mesmo sistema satisfazendo a condição inicial dada e que rastreie assintoticamente a trajetória periódica dada. Resolvemos esse problema localmente (para condições iniciais em uma vizinhança de um ponto da trajetória periódica) quando G é semi-simples e o sistema afim é Lie-determinado (i.e. controlável), e apenas para um classe de trajetórias periódicas (as quais denominamos \"regulares\"). Apresentamos por fim um conjunto de condições suficientes para a existência de tais trajetórias. / We treat the periodic motion planning problem: given a periodic trajectory of a control-affine driftless system in a compact and connected Lie group G and an initial condition in G, find another trajectory of the same system satisfying the initial condition given and that asymptotically tracks the periodic trajectory. We solve this problem locally (for initial conditions in a neighborhood of some point of the periodic trajectory) when G is semisimple and the system is Lie-determined (i.e. controllable), and only for a class of periodic trajectories (which we call \"regular\"). Finally we present a set of sufficient conditions to ensure the existence of such trajectories.

Tratamos o problema do planejamento periódico de trajetórias: fixados uma trajetória periódica de um sistema afim sem arrasto em um grupo de Lie compacto e conexo G e uma condição inicial em G, encontrar outra trajetória do mesmo sistema satisfazendo a condição inicial dada e que rastreie assintoticamente a trajetória periódica dada. Resolvemos esse problema localmente (para condições iniciais em uma vizinhança de um ponto da trajetória periódica) quando G é semi-simples e o sistema afim é Lie-determinado (i.e. controlável), e apenas para um classe de trajetórias periódicas (as quais denominamos \"regulares\"). Apresentamos por fim um conjunto de condições suficientes para a existência de tais trajetórias. / We treat the periodic motion planning problem: given a periodic trajectory of a control-affine driftless system in a compact and connected Lie group G and an initial condition in G, find another trajectory of the same system satisfying the initial condition given and that asymptotically tracks the periodic trajectory. We solve this problem locally (for initial conditions in a neighborhood of some point of the periodic trajectory) when G is semisimple and the system is Lie-determined (i.e. controllable), and only for a class of periodic trajectories (which we call \"regular\"). Finally we present a set of sufficient conditions to ensure the existence of such trajectories.

Within the past decades, wavelets and associated wavelet transforms have been intensively investigated in both applied and pure mathematics. They and the related multi-scale analysis provide essential tools to describe, analyse and modify signals, images or, in rather abstract concepts, functions, function spaces and associated operators. We introduce the concept of diffusive wavelets where the dilation operator is provided by an evolution like process that comes from an approximate identity. The translation operator is naturally defined by a regular representation of the Lie group where we want to construct wavelets. For compact Lie groups the theory can be formulated in a very elegant way and also for homogeneous spaces of those groups we formulate the theory in the theory of non-commutative harmonic analysis. Explicit realisation are given for the Rotation group SO(3), the k-Torus, the Spin group and the n-sphere as homogeneous space. As non compact example we discuss diffusive wavelets on the Heisenberg group, where the construction succeeds thanks to existence of the Plancherel measure for this group. The last chapter is devoted to the Radon transform on SO(3), where the application on diffusive wavelets can be used for its inversion. The discussion of a variational spline approach provides criteria for the choice of points for measurements in concrete applications.

Within the past decades, wavelets and associated wavelet transforms have been intensively investigated in both applied and pure mathematics. They and the related multi-scale analysis provide essential tools to describe, analyse and modify signals, images or, in rather abstract concepts, functions, function spaces and associated operators. We introduce the concept of diffusive wavelets where the dilation operator is provided by an evolution like process that comes from an approximate identity. The translation operator is naturally defined by a regular representation of the Lie group where we want to construct wavelets. For compact Lie groups the theory can be formulated in a very elegant way and also for homogeneous spaces of those groups we formulate the theory in the theory of non-commutative harmonic analysis. Explicit realisation are given for the Rotation group SO(3), the k-Torus, the Spin group and the n-sphere as homogeneous space. As non compact example we discuss diffusive wavelets on the Heisenberg group, where the construction succeeds thanks to existence of the Plancherel measure for this group. The last chapter is devoted to the Radon transform on SO(3), where the application on diffusive wavelets can be used for its inversion. The discussion of a variational spline approach provides criteria for the choice of points for measurements in concrete applications.

On s'intéresse dans cette thèse à l'étude de variables aléatoires sur les groupes de Lie compacts classiques. On donne une déformation du calcul de Weingarten tel qu'il a été introduit par B. Collins et P. Sniady. On fait une étude asymptotique du mouvement brownien sur les groupes de Lie compacts de grande dimension en obtenant des nouveaux résultats de fluctuations. Deux nouveaux objets, que l'on appelle champ maître gaussien planaire et champ maître orienté planaire, sont introduits pour décrire le comportement asymptotique des mesures de Yang-Mills pour des groupes de structure de grande dimension. / In the following text, we are interested in the study of Lie-groups valued random variables. We give a deformation of the Weingarten calculus introduced by Benoît Collins and Piotr Sniady. We study the asymptotic behavior of Brownian motion on compact Lie groups in high dimensions and obtain new fluctuations results. Two new objects called the planar gaussian master field and the planar oriented master field are introduced here to describe the asymptotic behavior of the Yang-Mills measure as the dimension of the structure group is large.