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Romon, Gabriel. "Contributions to high-dimensional, infinite-dimensional and nonlinear statistics". Electronic Thesis or Diss., Institut polytechnique de Paris, 2023. http://www.theses.fr/2023IPPAG013.
Pełny tekst źródłaThree topics are explored in this thesis: inference in high-dimensional multi-task regression, geometric quantiles in infinite-dimensional Banach spaces and generalized Fréchet means in metric trees. First, we consider a multi-task regression model with a sparsity assumption on the rows of the unknown parameter matrix. Estimation is performed in the high-dimensional regime using the multi-task Lasso estimator. To correct for the bias induced by the penalty, we introduce a new data-driven object that we call the interaction matrix. This tool lets us develop normal and chi-square asymptotic distribution results, from which we obtain confidence intervals and confidence ellipsoids in sparsity regimes that are not covered by the existing literature. Second, we study the geometric quantile, which generalizes the classical univariate quantile to normed spaces. We begin by providing new results on the existence and uniqueness of geometric quantiles. Estimation is then conducted with an approximate M-estimator and we investigate its large-sample properties in infinite dimension. When the population quantile is not uniquely defined, we leverage the theory of variational convergence to obtain asymptotic statements on subsequences in the weak topology. When there is a unique population quantile, we show that the estimator is consistent in the norm topology for a wide range of Banach spaces including every separable uniformly convex space. In separable Hilbert spaces, we establish novel Bahadur-Kiefer representations of the estimator, from which asymptotic normality at the parametric rate follows. Lastly, we consider measures of central tendency for data that lives on a network, which is modeled by a metric tree. The location parameters that we study are called generalized Fréchet means: they obtained by relaxing the square in the definition of the Fréchet mean to an arbitrary convex nondecreasing loss. We develop a notion of directional derivative in the tree, which helps us locate and characterize the minimizers. We examine the statistical properties of the corresponding M-estimator: we extend the notion of stickiness to the setting of metrics trees, and we state a non-asymptotic sticky theorem, as well as a sticky law of large numbers. For the Fréchet median, we develop non-asymptotic concentration bounds and sticky central limit theorems
Haïssinsky, Peter. "Dynamique conforme dans les espaces métriques". Habilitation à diriger des recherches, Université de Provence - Aix-Marseille I, 2009. http://tel.archives-ouvertes.fr/tel-00367259.
Pełny tekst źródłaHan, Bang-Xian. "Analyse dans les espaces métriques mesurés". Thesis, Paris 9, 2015. http://www.theses.fr/2015PA090014/document.
Pełny tekst źródłaThis thesis concerns in some topics on calculus in metric measure spaces, in connection with optimal transport theory and curvature-dimension conditions. We study the continuity equations on metric measure spaces, in the viewpoint of continuous functionals on Sobolev spaces, and in the viewpoint of the duality with respect to absolutely continuous curves in the Wasserstein space. We study the Sobolev spaces of warped products of a real line and a metric measure space. We prove the 'Pythagoras theorem' for both cartesian products and warped products, and prove Sobolev-to-Lipschitz property for warped products under a certain curvature-dimension condition. We also prove the identification of p-weak gradients under curvature-dimension condition, without the doubling condition or local Poincaré inequality. At last, using the non-smooth Bakry-Emery theory on metric measure spaces, we obtain a Bochner inequality and propose a definition of N-Ricci tensor
Baudier, Florent. "Plongements des espaces métriques dans les espaces de Banach". Phd thesis, Université de Franche-Comté, 2009. http://tel.archives-ouvertes.fr/tel-00477415.
Pełny tekst źródłaLehbab, Imène. "Problèmes métriques dans les espaces de Grassmann". Electronic Thesis or Diss., Mulhouse, 2023. http://www.theses.fr/2023MULH6508.
Pełny tekst źródłaThis work contributes to the field of metric geometry of the complex projective plane CP2 and the real Grassmannian manifold of the planes in R6. More specifically, we study all p-tuples, p ≥ 3, of equiangular lines in C3 or equidistant points in CP2, and p-tuples of equi-isoclinic planes in R6. Knowing that 9 is the maximum number of equiangular lines that can be constructed in C3, we develop a method to obtain all p-tuples of equiangular lines for all p ϵ [3,9]. In particular, we construct in C3 five congruence classes of quadruples of equiangular lines, one of which depends on a real parameter ɣ, which we extend to an infinite family of sextuples of equiangular lines depending on the same real parameter ɣ. In addition, we give the angles for which our sextuples extend beyond and up to 9-tuples. We know that there exists a p-tuple, p ≥ 3, of equi-isoclinic planes generating Rr, r ≥ 4, with parameter c, 0< c <1, if and only if there exists a square symmetric matrix, called Seidel matrix, of p × p square blocks of order 2, whose diagonal blocks are all zero and the others are orthogonal matrices in O(2) and whose smallest eigenvalue is equal to - 1/c and has multiplicity 2p-r. In this thesis, we investigate the case r=6 and we also show that we can explicitly determine the spectrum of all Seidel matrices of order 2p, p ≥ 3 whose off-diagonal blocks are in {R0, S0} where R0 and S0 are respectively the zero-angle rotation and the zero-angle symmetry. We thus show an unexpected link between some p-tuples of equi-isoclinic planes in Rr and simple graphs of order p
Munnier, Vincent. "Analyse et rectifiabilité dans les espaces métriques singuliers". Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00630615.
Pełny tekst źródłaKhatib, Souad El. "Espaces métriques dans la théorie des ensembles flous". Lyon 1, 1986. http://www.theses.fr/1986LYO10060.
Pełny tekst źródłaKouahla, Zineddine. "Indexation dans les espaces métriques : index arborescent et parallélisation". Phd thesis, Université de Nantes, 2013. http://tel.archives-ouvertes.fr/tel-00912743.
Pełny tekst źródłaBelkhirat, Abdelhadi. "Sur des métriques dans l'espace de Teichmüller". Université Louis Pasteur (Strasbourg) (1971-2008), 2003. http://www.theses.fr/2003STR13126.
Pełny tekst źródłaPichard, Karine. "Equations différentielles dans les espaces métriques : Application à l'évolution de domaines". Pau, 2001. http://www.theses.fr/2001PAUU3021.
Pełny tekst źródłaChepoi, Victor. "Métriques et convexité dans les graphes et espaces discrèts : propriétés et algorithmes". Aix-Marseille 2, 1997. http://www.theses.fr/1997AIX22124.
Pełny tekst źródłaBoutayeb, Salahaddine. "Sur les estimations du noyau de la chaleur dans les espaces métriques doublants". Cergy-Pontoise, 2010. http://www.theses.fr/2010CERG0498.
Pełny tekst źródłaIn the setting of a Riemannian manifold and more generally in a measured metric space endowed with a symmetric submarkovian semigroup, we are interested to generalize some heat kernel estimates results obtained by various authors when the volume growth is polynomial, to a more general case of the volume growth, called the doubling case. In this thesis, we will prove the following results: -Characterization of the Gaussian upper estimate by some one parameter weighted inequalities. -Obtaining the Gaussian upper estimate from the lower estimate. -Assuming the Gaussian upper estimate, we characterize the lower estimate by some Hölder type inequalities
Ribeiro, Porto Ferreira Monica. "Optimisation des requêtes de similarité dans les espaces métriques répondant aux besoins des usagers". Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00837734.
Pełny tekst źródłaRazafindrakoto, Razafy. "Quelques propriétés des continua dans les espaces métriques compacts, une application sur l'indice de point fixe". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq21822.pdf.
Pełny tekst źródłaRazafindrakoto, Razafy. "Quelques propriétés des continua dans les espaces métriques compacts, une application sur l'indice de point fixe". Mémoire, Université de Sherbrooke, 1996. http://savoirs.usherbrooke.ca/handle/11143/4342.
Pełny tekst źródłaHillion, Erwan. "Analyse et géométrie dans les espaces métriques mesurés : inégalités de Borell-Brascamp-Lieb et conjecture de Olkin-Shepp". Toulouse 3, 2010. http://thesesups.ups-tlse.fr/1592/.
Pełny tekst źródłaThe work done during this PhD thesis is based on the theory of Ricci curvature bounds in measured length spaces, developed by Sturm, Lott and Villani, using deep results coming from the optimal transportation theory. In a first part, we study two families of functional inequalities, called Prékopa-Leindler and Borell-Brascamp-Lieb inequalities, and show that they allows us to give an alternate definition to Ricci curvature bounds, satisfying a "wishlist" similar to the one fulfilled by the Sturm-Lott- Villani condition CD(K,N). The second part is about a possible generalization of Sturm-Lott-Villani definition in a discrete setting. We emphasise the case of the translation of probability measures on a linear graph, and study the convexity of entropy along such a translation. The expression of this translation as a binomial convolution enlightens a conjecture stated by Olkin and Shepp about the entropy of sums of idependent Bernoulli random variables, for which we give a partial proof
Herzlich, Marc. "Metriques privilegiees dans la classe conforme d'une variete asymptotiquement plate, et applications". Palaiseau, Ecole polytechnique, 1996. http://www.theses.fr/1996EPXX0031.
Pełny tekst źródłaRobitaille, Jean-François. "Analyse métrique de structures HI dans le plan galactique". Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25570/25570.pdf.
Pełny tekst źródłaLazar, Cosmin. "Méthodes non supervisées pour l’analyse des données multivariées". Reims, 2008. http://theses.univ-reims.fr/exl-doc/GED00000846.pdf.
Pełny tekst źródłaMany scientific disciplines deal with multivariate data. Different recordings of the same phenomenon are usually embedded in a multivariate data set. Multivariate data analysis gathers efficient tools for extracting relevant information in order to comprehend the phenomenon in study. Gathering data into groups or classes according to some similarity criteria is an essential step in the analysis. Intrinsic dimension or dimension reduction of multivariate data, the choice of the similarity criterion, cluster validation are problems which still let open questions. This work tries to make a step further concerning two of the problems mentioned above: the choice of the similarity measure for data clustering and the dimension reduction of multivariate data. The choice of the similarity measure for data clustering is investigated from the concentration phenomenon of metrics point of view. Non Euclidean metrics are tested as alternative to the classical Euclidian distance as similarity measure. We tested if less concentrated metrics are more discriminative for multivariate data clustering. We also proposed indices which take into account the inter-classes distance (e. G. Davies-Bouldin index) in order to find the optimal metric when the classes are supposed to be Gaussian. Blind Source Separation (BSS) methods are also investigated for dimension reduction of multivariate data. A BSS method based on a geometrical interpretation of the linear mixing model is proposed. BSS methods which take into account application constraints are used for dimension reduction in two different applications of multivariate imaging. These methods allow the extraction of meaningful factors from the whole data set; they also allow reducing the complexity and the computing time of the clustering algorithms which are used further in analysis. Applications on multivariate image analysis are also presented
Khalil, André. "Analyse structurelle de l'hydrogène neutre dans la voie lactée". Thesis, Université Laval, 2004. http://www.theses.ulaval.ca/2004/22165/22165.pdf.
Pełny tekst źródłaStars live and die by rejecting matter in the interstellar medium (ISM), where they were born. We have analyzed the neutral hydrogen component of the ISM. The data come from the Canadian portion of the International Galactic Plane Survey which aims the spectroscopic imaging of the neutral hydrogen from our Galaxy. We have used two mathematical image analysis tools: Metric Space Technique (MST) and the Wavelet Transform Modulus Maxima (WTMM) method. The MST is an image analysis mathematical formalism that allows one to quantitatively compare the complexity of the studied objects. We have improved the tool mathematically and technically before using it to characterize the complexity of 28 neutral hydrogen regions. After classifying the 28 objects, we have found some correlations between this ranking and the physical properties of the underlying objects, for example: (1) The complexity of the photodissociated neutral hydrogen regions increases with the flux of UV photons; and (2) the complexity of neutral hydrogen regions increases with the age of the supernovae remnants to which they are associated. The WTMM method is a multifractal formalism based on the wavelet transform. The results we obtain from this method concern the multifractal and anisotropic properties of neutral hydrogen in our Galaxy. Earth clouds exhibit multifractal properties. We have shown that the neutral hydrogen from our galactic disk is monofractal. By analyzing separately spiral arms and the inter-arm regions, we have discovered an anisotropic signature and that the horizontal structures and more complex than the vertical structures. This anisotropy is independent of scale for the inter-arms while it is depedent of scale for the spiral arms. The investigated hypotheses to obtain some physical explanations are: the scale-height gradient, the density wave, star formation activity, photo-levitation of dusty clouds, random motions of neutral hydrogen clouds, corrugation and turbulence.
Lavenant, Hugo. "Courbes et applications optimales à valeurs dans l'espace de Wasserstein". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS112/document.
Pełny tekst źródłaThe Wasserstein space is the space of probability measures over a given domain endowed with the quadratic Wasserstein distance. In this work, we study variational problems where the unknowns are mappings valued in the Wasserstein space. When the source space is a segment, i.e. when the unknowns are curves valued in the Wasserstein space, we are interested in models where, in addition to the action of the curves, there are some terms which penalize congested configurations. We develop techniques to extract regularity from the minimizers thanks to the interplay between optimal density evolution (minimization of the action) and penalization of congestion, and we apply them to the study of Mean Field Games and the variational formulation of the Euler equations. When the source space is no longer a segment but a domain of a Euclidean space, we consider only the Dirichlet problem, i.e. the minimization of the action (which can be called the Dirichlet energy) among mappings sharing a fixed value on the boundary of the source space. The solutions are called harmonic mappings valued in the Wasserstein space. We prove that the different definitions of the Dirichlet energy in the literature turn out to be equivalent; that the Dirichlet problem is well-posed under mild assumptions; that the superposition principle fails if the source space is no longer a segment; that a sort of maximum principle holds; and we provide a numerical method to compute these harmonic mappings
Wisniewski, Guillaume. "Apprentissage dans les espaces structurés : application à l'étiquetage de séquences et à la transformation automatique de documents". Paris 6, 2007. http://www.theses.fr/2007PA066525.
Pełny tekst źródłaScaman, Kevin. "Etude et contrôle de phénomènes diffusifs dans un réseau". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLN039/document.
Pełny tekst źródłaThe propagation of a characteristic through a network is the subject of study of many scientific fields. Epidemics, viral marketing or information propagation through a social network are among the many examples of real phenomena modeled by the evolution of a characteristic propagating through the edges of a network. Thus, being capable of acting on these diffusion processes is of capital interest for many fields. Despite the large literature about the theoretical aspects of diffusion processes, and more specifically the discovery of an epidemic threshold under which the propagation is not sustainable, a number of practical limitations prevent the use of these studies in real-life scenarios. In this thesis, we work on reducing the distance separating theory from practice, following three distinct research directions: the generalization of theoretical results to a larger, and more realistic, class of diffusion models, the development of efficient dynamic control measures utilizing the structure of network to its advantage, and, finally, the definition of new mathematical tools bridging the gap between spatial and network approaches in epidemiology. More specifically, our work allows the rigorous analysis of the behavior of a network's characteristics when it converges, in a structural sense, to a given metric space, and could open the way to the application of control strategies on networks to spatial and macroscopic information (e.g. transportation or demographic data) about the contact network in a given population
Teyssandier, Benoît. "Analyse dans l'espace des phases de champs acoustiques : application à des guides de section variable et à des espaces clos". Le Mans, 2004. http://cyberdoc.univ-lemans.fr/theses/2004/2004LEMA1007.pdf.
Pełny tekst źródłaThe airn of this work is ta study the local behavicr Of twc-dimensionai (2D) barrnonic acoustic field y rneans of a joint "space-wave nurnbee'representation. A function defined in the phase space domain (x,y,kx,ky) is assaciated ta a signal which is a function of spatial coordinates (x,y). In order ta represent such a function, @two methods are proposed ta realize it. The first is ta associate ta each point (x,y) of the wave field a 2D wave nurnber spectrurn (k-x,k-y), called local spectrum. The second is ta process by other coordinates the wave field alorig an arbitrary direction, introduced in quantum mechanics for the study of classical billiards, and is provided by the Birkhoff variables (s,sing). Three applications concerning guided propagation are developped here. In chapter 2, the two phase space diagrarns (local spectrum and Birkhoff analysis) are estirnated thanks ta uadratic phase space distributions. Simulations are presented for wave fields in a 2D planar waveguide for a pedagogical point of view with Gaussian bearn or point source excitation, and non-uniform waveguides as a sudden area expansion chamber and an open billiard with a single incoming mode at the entrarice of each of thern. Local spectrurn and Birkhoff analysis are used in order ta identify the structure hidden in the field. Ln chapter 3, the reassignrnent method is used ta analyse eigen-modes of different cavities or billiards, regarding regular, mixed or irregular billiards. This chapter shows how the reassigned Husimi distribution is used ta define specific phenomena in an elgenstate as scars. In chapter 4, the analysis of rnultimodai propagation !ri a varying cross section waveguide with the help of phase space distributions is used in order ta estirnate the local variations of the dispersion curves of the propagatinq modes. The reassignment rnethod on the Husimi distribution is an attractive tool ta define adiabatic transition, mode coupling or trapped modes. Lize inverse problem, vibrating structure
Teyssandier, Benoît Depollier Claude. "Analyse dans l'espace des phases de champs acoustiques application à des guides de section variable et à des espaces clos /". [S.l.] : [s.n.], 2004. http://cyberdoc.univ-lemans.fr/theses/2004/2004LEMA1007.pdf.
Pełny tekst źródłaPycke, Jean-Renaud. "Un lien entre le développement de Karhunen-Loève de certains processus gaussiens et le laplacien dans des espaces de Riemann". Paris 6, 2003. http://www.theses.fr/2003PA066477.
Pełny tekst źródłaEs-Sahib, Aziz. "Espérances d'une variable aléatoire à valeurs dans un espace métrique". Rouen, 1998. http://www.theses.fr/1999ROUES037.
Pełny tekst źródłaSouche, Estelle. "Quasi-isométries et quasi-plans dans l'étude des groupes discrets". Aix-Marseille 1, 2001. http://www.theses.fr/2001AIX11048.
Pełny tekst źródłaEssoloh, Mehdi. "Méthodes d'apprentissage à noyau pour l'estimation distribuée dans les réseaux de capteurs sans fil". Troyes, 2008. http://www.theses.fr/2009TROY0022.
Pełny tekst źródłaThis thesis proposes a new frame for estimation problems in wireless sensor networks thanks to learning methods built on reproducing kernels. In a first part, our work deals with the sensor network localization problem thanks to reproducing kernel Hilbert space formalism. While respecting energy constraints and limitations in computation capabilities, coordinate estimation is executed thanks to range measurements between sensors and a priori known locations of some small fraction of deployed sensors. By considering these dissimilarities as elements of a Gram matrix, we investigate two distributed approaches: one is related to the pre-image problem, widely used in denoising applications, the other one is based on a kernel matrix regression approach, recently introduced in bio-engineering. In a second part, we propose a distributed learning strategy for temperature field estimation in wireless sensor networks. We note that sparse approximation, enabling an efficient control of the order model, holds with algorithmic constraints of wireless sensor networks. Our work is based on non-linear adaptive filtering techniques with kernels and we demonstrate its relevant use for distributed regression problem in wireless sensor networks
Charlier, Benjamin. "Étude des propriétés statistiques des moyennes de Fréchet dans des modèles de déformations pour l'analyse de courbes et d'images en grande dimension". Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1407/.
Pełny tekst źródłaWe are concerned with the statistical analysis of data observed with extra nuisance deformations. To this end, we first introduce a new class of semi-parametric deformable models. These models can be used to study the variability of time dependent curves or high dimensional images. We suppose that the curves or images at hand are generated by a noisy ideal mean pattern on which act some deformations operators. We then study the estimation of the parameters of interest of such models in the general case and in the particular case of planar curves observed with some rotation, translation and scaling. In a second part, we study the notion of mean in non-Euclidean spaces. More precisely, we study the conditions of existence of the Fréchet mean in the unit circle of the plane endowed with the arclength distance
Tenenhaus, Arthur. "Apprentissage dans les espaces de grande dimension : Application à la caractérisation de tumeurs noires de la peau à partir d'images". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2006. http://tel.archives-ouvertes.fr/tel-00142439.
Pełny tekst źródłaLes deux chapitres suivants proposent de nouvelles méthodes, découlant de cette étude. Elles se fondent sur des principes de réduction de dimension supervisée en se focalisant principalement sur la régression PLS, particulièrement bien adaptée à la gestion de données de grande dimension. Il s'agissait de concevoir des algorithmes de classification s'appuyant sur les principes algorithmiques de la régression PLS. Nous avons proposé, la Kernel Logistic PLS, modèle de classification nonlinéaire et binaire basé à la fois sur la construction de variables latentes et sur des transformations du type Empirical Kernel Map. Nous avons étendu la KL-PLS au cas où la variable à prédire est polytomique donnant naissance à la Kernel Multinomial Logistic PLS regression.
Enfin dans les deux derniers chapitres, nous avons appliqué ces méthodes à de nombreux domaines, notamment en analyse d'images. Nous avons ainsi contribué au développement d'une application en vraie grandeur dans le domaine médical en élaborant un outil d'aide au diagnostic de tumeurs noires de la peau à partir d'images.
Brasco, Lorenzo. "Geodesics and PDE methods in transport models". Phd thesis, Université Paris Dauphine - Paris IX, 2010. http://tel.archives-ouvertes.fr/tel-00578447.
Pełny tekst źródłaThanwerdas, Yann. "Géométries riemanniennes et stratifiées des matrices de covariance et de corrélation". Thesis, Université Côte d'Azur, 2022. http://www.theses.fr/2022COAZ4024.
Pełny tekst źródłaIn many applications, the data can be represented by covariance matrices or correlation matrices between several signals (EEG, MEG, fMRI), physical quantities (cells, genes), or within a time window (autocorrelation). The set of covariance matrices forms a convex cone that is not a Euclidean space but a stratified space: it has a boundary which is itself a stratified space of lower dimension. The strata are the manifolds of covariance matrices of fixed rank and the main stratum of Symmetric Positive Definite (SPD) matrices is dense in the total space. The set of correlation matrices can be described similarly.Geometric concepts such as geodesics, parallel transport, Fréchet mean were proposed for generalizing classical computations (interpolation, extrapolation, registration) and statistical analyses (mean, principal component analysis, classification, regression) to these non-linear spaces. However, these generalizations rely on the choice of a geometry, that is a basic operator such as a distance, an affine connection, a Riemannian metric, a divergence, which is assumed to be known beforehand. But in practice there is often not a unique natural geometry that satisfies the application constraints. Thus, one should explore more general families of geometries that exploit the data properties.First, the geometry must match the problem. For instance, degenerate matrices must be rejected to infinity whenever covariance matrices must be non-degenerate. Second, we should identify the invariance of the data under natural group transformations: if scaling each variable independently has no impact, then one needs a metric invariant under the positive diagonal group, for instance a product metric that decouples scales and correlations. Third, good numerical properties (closed-form formulae, efficient algorithms) are essential to use the geometry in practice.In my thesis, I study geometries on covariance and correlation matrices following these principles. In particular, I provide the associated geometric operations which are the building blocks for computing with such matrices.On SPD matrices, by analogy with the characterization of affine-invariant metrics, I characterize the continuous metrics invariant by O(n) by means of three multivariate continuous functions. Thus, I build a classification of metrics: the constraints imposed on these functions define nested classes satisfying stability properties. In particular, I reinterpret the class of kernel metrics, I introduce the family of mixed-Euclidean metrics for which I compute the curvature, and I survey and complete the knowledge on the classical metrics (log-Euclidean, Bures-Wasserstein, BKM, power-Euclidean).On full-rank correlation matrices, I compute the Riemannian operations of the quotient-affine metric. Despite its appealing construction and its invariance under permutations, I show that its curvature is of non-constant sign and unbounded from above, which makes this geometry practically very complex. I introduce computationally more convenient Hadamard or even log-Euclidean metrics, along with their geometric operations. To recover the lost invariance under permutations, I define two new permutation-invariant log-Euclidean metrics, one of them being invariant under a natural involution on full-rank correlation matrices. I also provide an efficient algorithm to compute the associated geometric operations based on the scaling of SPD matrices.Finally, I study the stratified Riemannian structure of the Bures-Wasserstein distance on covariance matrices. I compute the domain of definition of geodesics and the injection domain within each stratum and I characterize the length-minimizing curves between all the strata
Gaillard, David. "Gestion concertée du ruissellement-érosif dans les espaces agricoles des plateaux de grande culture : analyse spatiale, approche socio-économique et mise en place d'une dynamique collective d'aménagement : exemple de la Seine-Maritime". Rouen, 2004. http://www.theses.fr/2004ROUEL490.
Pełny tekst źródłaPeaty slide inundation in the Pays de Caux became a priority for regional development. The run-off is the most important factor that can explain the fact and frequency of this type of inundation. A space ans systemic approach at the scale of the elementary water-shed allows co-ordinated actions to appear, that have been decided and approved on a collective basis, which is a guaranty of effectiveness and efficiency. In addition to selective post corrective measures located right below vulnerable areas, efforts and reflections are made about the manner to reconsidering upper-water-shed practices. Mixing both significant scales ( elementary water-shed and farm), space analysis and modelling allow to suggest measures to fight run-off and erosion. Tese measures are individuals but with collective imperatives, which guatantees the homogenisation of devices on the area at risk, and implies a mediation and a dialogue aiming at reorganising the space of the farms. The socio-economic approach allows to adapt the erosive run-off limitation requirements to the financial and structural constraints of the agricultural company
Chilowicz, Michel. "Recherche de similarité dans du code source". Phd thesis, Université Paris-Est, 2010. http://tel.archives-ouvertes.fr/tel-00587628.
Pełny tekst źródłaSchmitt, Guillaume. "Valeurs et usages de l'espace : approches méthodologiques des dynamiques foncières dans la région Nord-Pas-de-Calais". Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10076/document.
Pełny tekst źródłaOn account of the sustainability principle and because of the complexity of land-use policy, public sector players in spatial planning are wondering about the evolution of space uses and about our knowledge of land markets. The work for this thesis was conducted in the context of workshops associating local authorities and state authorities This thesis builds on a set of socioeconomic data, on public land-use policies, on land markets and on land use at various spatial and temporal scales. First of all, it maps the changing themes in land studies over the past thirty years and attempts to define an observation framework to deal with the recurring problem of access to comprehensive data on land markets. The land planning methods implemented in the Nord-Pas de Calais region are also analysed by comparing them with the methods used in the rest of France. Secondly, the uncertainties regarding information about land markets and land use led us to collect, estimate and select data adapted to an observation framework intended for public sector players. Thirdly, land use and its changes are studied between 1990 and 2005 in Europe, in France and in the Nord-Pas de Calais region by means of a method combining spatial analysis techniques with the identification of the stakes involved in spatial management through reading planning documents and interviews with territorial managers. Fourthly, the spatial and temporal dimensions of land markets are analysed between 1989 and 2005 in the Nord-Pas de Calais region. Particular attention is paid to the relations between property sales and land use changes, as well as to the roles of sellers and purchasers in the uses and values of space
Besson, Rémi. "Decision making strategy for antenatal echographic screening of foetal abnormalities using statistical learning". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLX037/document.
Pełny tekst źródłaIn this thesis, we propose a method to build a decision support tool for the diagnosis of rare diseases. We aim to minimize the number of medical tests necessary to achieve a state where the uncertainty regarding the patient's disease is less than a predetermined threshold. In doing so, we take into account the need in many medical applications, to avoid as much as possible, any misdiagnosis. To solve this optimization task, we investigate several reinforcement learning algorithm and make them operable in our high-dimensional. To do this, we break down the initial problem into several sub-problems and show that it is possible to take advantage of the intersections between these sub-tasks to accelerate the learning phase. The strategies learned are much more effective than classic greedy strategies. We also present a way to combine expert knowledge, expressed as conditional probabilities, with clinical data. This is crucial because the scarcity of data in the field of rare diseases prevents any approach based solely on clinical data. We show, both empirically and theoretically, that our proposed estimator is always more efficient than the best of the two models (expert or data) within a constant. Finally, we show that it is possible to effectively integrate reasoning taking into account the level of granularity of the symptoms reported while remaining within the probabilistic framework developed throughout this work