Nous allons étudier les propriétés des courbes algébriques sur des surfaces K3 spéciales, du point de vue de la théorie de Brill-Noether.La démonstration de Lazarsfeld du théorème de Gieseker-Petri a mis en lumière l'importance de la théorie de Brill-Noether des courbes admettant un plongement dans une surface K3. Nous allons donner une démonstration détaillée de ce résultat classique, inspirée par les idées de Pareschi. En suite, nous allons décrire le théorème de Green et Lazarsfeld, fondamental pour tout notre travail, qui établit le comportement de l'indice de Clifford des courbes sur les surfaces K3.Watanabe a montré que l'indice de Clifford de courbes sur certaines surfaces K3, admettant un recouvrement double des surfaces de del Pezzo, est calculé en utilisant les involutions non-symplectiques. Nous étudions une situation similaire pour des surfaces K3 avec un réseau de Picard isomorphe à U(m), avec m>0 un entier quelconque. Nous montrons que la gonalité et l'indice de Clifford de toute courbe lisse sur ces surfaces, avec une seule exception déterminée explicitement, sont obtenus par restriction des fibrations elliptiques de la surface. Ce travail est basé sur l'article suivant :M. Ramponi, Gonality and Clifford index of curves on elliptic K3 surfaces with Picard number two, Archiv der Mathematik, 106(4), p. 355–362, 2016.Knutsen et Lopez ont étudié en détail la théorie de Brill-Noether des courbes sur les surfaces d'Enriques. En appliquant leurs résultats, nous allons pouvoir calculer la gonalité et l'indice de Clifford de toute courbe lisse sur les surfaces K3 qui sont des recouvrements universels d'une surface d'Enriques. Ce travail est basé sur l'article suivant :M. Ramponi, Special divisors on curves on K3 surfaces carrying an Enriques involution, Manuscripta Mathematica, 153(1), p. 315–322, 2017. / We study the properties of algebraic curves lying on special K3 surfaces, from the viewpoint of Brill-Noether theory.Lazarsfeld's proof of the Gieseker-Petri theorem has revealed the importance of the Brill-Noether theory of curves which admit an embedding in a K3 surface. We give a proof of this classical result, inspired by the ideas of Pareschi. We then describe the theorem of Green and Lazarsfeld, a key result for our work, which establishes the behaviour of the Clifford index of curves on K3 surfaces.Watanabe showed that the Clifford index of curves lying on certain special K3 surfaces, realizable as a double covering of a smooth del Pezzo surface, can be determined by a direct use of the non-simplectic involution carried by these surfaces. We study a similar situation for some K3 surfaces having a Picard lattice isomorphic to U(m), with m>0 any integer. We show that the gonality and the Clifford index of all smooth curves on these surfaces, with a single, explicitly determined exception, are obtained by restriction of the elliptic fibrations of the surface. This work is based on the following article:M. Ramponi, Gonality and Clifford index of curves on elliptic K3 surfaces with Picard number two, Archiv der Mathematik, 106(4), p. 355-362, 2016.Knutsen and Lopez have studied in detail the Brill-Noether theory of curves lying on Enriques surfaces. Applying their results, we are able to determine and compute the gonality and Clifford index of any smooth curve lying on the general K3 surface which is the universal covering of an Enriques surface. This work is based on the following article:M. Ramponi, Special divisors on curves on K3 surfaces carrying an Enriques involution, Manuscripta Mathematica, 153(1), p. 315-322, 2017.

Bundle adjustment is the process of simultaneously optimizing camera poses and 3D structure given image point tracks. In structure-from-motion, it is typically used as the final refinement step due to the nonlinearity of the problem, meaning that it requires sufficiently good initialization. Contrary to this belief, recent literature showed that useful solutions can be obtained even from arbitrary initialization for fixed-rank matrix factorization problems, including bundle adjustment with affine cameras. This property of wide convergence basin of high quality optima is desirable for any nonlinear optimization algorithm since obtaining good initial values can often be non-trivial. The aim of this thesis is to find the key factor behind the success of these recent matrix factorization algorithms and explore the potential applicability of the findings to bundle adjustment, which is closely related to matrix factorization. The thesis begins by unifying a handful of matrix factorization algorithms and comparing similarities and differences between them. The theoretical analysis shows that the set of successful algorithms actually stems from the same root of the optimization method called variable projection (VarPro). The investigation then extends to address why VarPro outperforms the joint optimization technique, which is widely used in computer vision. This algorithmic comparison of these methods yields a larger unification, leading to a conclusion that VarPro benefits from an unequal trust region assumption between two matrix factors. The thesis then explores ways to incorporate VarPro to bundle adjustment problems using projective and perspective cameras. Unfortunately, the added nonlinearity causes a substantial decrease in the convergence basin of VarPro, and therefore a bootstrapping strategy is proposed to bypass this issue. Experimental results show that it is possible to yield feasible metric reconstructions and pose estimations from arbitrary initialization given relatively clean point tracks, taking one step towards initialization-free structure-from-motion.

La simulation d'écoulements dans des géométries complexes nécessite la création de maillages parfois difficile à réaliser. La méthode de pénalisation proposée dans ce travail permet de simplifier cette étape. En effet, la résolution des équations qui gouvernent l'écoulement se fait sur un maillage plus simple mais non-adapté à la géométrie du problème. Les conditions aux limites sur les parties du domaine physique immergées dans le maillage sont prises en compte à travers l'ajout d'un terme de pénalisation dans les équations. Nous nous sommes intéressés à l'approximation du terme de pénalisation pour une discrétisation par volumes finis sur maillages décalés et colocatifs. Les cas tests de vérification réalisés attestent d'un ordre de convergence spatial égal à 2 pour la méthode de pénalisation appliquée à la résolution d'une équation de type Poisson ou des équations de Navier-Stokes. Enfin, on présente les résultats obtenus pour la simulation d'écoulements turbulents autour d'un cylindre à Re=3900 et à l'intérieur d'une partie d'un assemblage combustible à Re=9500. / The simulations of fluid flows in complex geometries require the generation of body-fitted meshes which are difficult to create.The penalty method developed in this work is useful to simplify the mesh generation task.The governing equations of fluid flow are discretized using a finite volume method on an unfitted mesh.The immersed boundary conditions are taken into account through a penalty term added to the governing equations.We are interested in the approximation of the penalty term using a finite volume discretization with collocated and staggered grid.The penalty method is second-order spatial accurate for Poisson and Navier-Stokes equations.Finally, simulations of turbulent flows around a cylinder at Re=3900 and turbulent motions in a rod bundle at Re=9500 are performed.

Les travaux présentés ici concernent le domaine de la localisation de véhicule par vision artificielle. Dans ce contexte, la trajectoire d’une caméra et la structure3D de la scène filmée sont estimées par une méthode d’odométrie visuelle monoculaire basée sur l’ajustement de faisceaux local. Les contributions de cette thèse sont plusieurs améliorations de cette méthode. L’incertitude associée à la position estimée n’est pas fournie par la méthode d’ajustement de faisceaux local. C’est pourtant une information indispensable pour pouvoir utiliser cette position, notamment dans un système de fusion multi-sensoriel. Une étude de la propagation d’incertitude pour cette méthode d’odométrie visuelle a donc été effectuée pour obtenir un calcul d’incertitude temps réel et représentant l’erreur de manière absolue (dans le repère du début de la trajectoire). Sur de longues séquences (plusieurs kilomètres), les méthodes monoculaires de localisation sont connues pour présenter des dérives importantes dues principalement à la dérive du facteur d’échelle (non observable). Pour réduire cette dérive et améliorer la qualité de la position fournie, deux méthodes de fusion ont été développées. Ces deux améliorations permettent de rendre cette méthode monoculaire exploitable dans le cadre automobile sur de grandes distances tout en conservant les critères de temps réel nécessaire dans ce type d’application. De plus, notre approche montre l’intérêt de disposer des incertitudes et ainsi de tirer parti de l’information fournie par d’autres capteurs. / The present work is about localisation of vehicle using computer vision methods. In this context, the camera trajectory and the 3D structure of the scene is estimated by a monocular visual odometry method based on local bundle adjustment. This thesis contributions are some improvements of this method. The uncertainty of the estimated position was not provided by the local bundle adjustment method. Indeed, this uncertainty is crucial in a multi-sensorial fusion system to use optimally the estimated position. A study of the uncertainty propagation in this visual odometry method has been done and an uncertainty calculus method has been designed to comply with real time performance. By the way, monocular visual localisation methods are known to have serious drift issues on long trajectories (some kilometers). This error mainly comes from bad propagation of the scale factor. To limit this drift and improve the quality of the given position, we proposed two data fusion methods between an odometer and the visual method. Finally, the two improvements presented here allow us to use visual localisation method in real urban environment on long trajectories under real time constraints.

Made available in DSpace on 2016-06-02T20:27:40Z (GMT). No. of bitstreams: 1 4629.pdf: 1448309 bytes, checksum: c6f5e451b1247c565791c643df7dc7d5 (MD5) Previous issue date: 2012-10-23 / Financiadora de Estudos e Projetos / This thesis was developed in two parts. Firstly, we consider a pair of fiber-preserving maps f1, f2 : M → M in a fiber bundle with base S1 and fiber Klein bottle. Using an algebraic system of equations we found in what situations the minimal coincidence set over S1 of the pair (f1, f2) is empty. In the second part, motivated by this problem, we consider a fiber-preserving map f : M → M in a fiber bundle with base S1 and fiber torus. Using the one-parameter fixed point theory we studied the minimal fixed point set over S1 of the map f. In some fiber bundle we classified completely this sets. / Esta tese foi desenvolvida em duas partes. Inicialmente, consideramos um par de aplicações que preserva fibra, f1, f2 : M → M, em um fibrado com base S1 e fibra garrafa de Klein. Utilizando-se de um sistema algébrico de equações, descobrimos em que situações o conjunto minimal de coincidências sobre S1 do par (f1, f2) é vazio. Na segunda parte, motivado por esse problema, consideramos uma aplicação que preserva fibra, f : M → M, em um fibrado com base S1 e fibra toro. Usando a teoria algébrica de ponto fixo a 1-parâmetro estudamos o conjunto minimal dos pontos fixos sobre S1 da aplicação f. Em alguns fibrados foi possível obter uma classificação completa desses conjuntos.

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Orientador: Tatiane Maria Rodrigues / Resumo: Em folhas de diversas espécies vegetais, a bainha de células que envolve os feixes vasculares se estende em direção à epiderme em ambas as faces do limbo formando extensões da bainha do feixe (EBF), o que caracteriza folhas heterobáricas. Folhas que não apresentam EBF são chamadas homobáricas. Pesquisas demostram que folhas homobáricas garantem maior difusão lateral de gases, enquanto as EBF podem atuar na condução de água e aumentar o desempenho fotossintético foliar garantindo a transferência de luz para as camadas mais internas do mesofilo. As diferenças morfofuncionais entre os dois tipos foliares parecem estar relacionadas ao ambiente onde as plantas ocorrem e à sua distribuição nos diferentes estratos vegetacionais. Entretanto, para formações vegetais no Brasil não foram encontrados estudos sobre a distribuição de espécies com folhas homobáricas e heterobáricas. Esse trabalho teve como objetivo estudar a anatomia foliar de espécies herbáceas, arbustivas e arbóreas na floresta estacional semidecídua, cerradão e cerrado stricto sensu a fim de identificar folhas homobáricas e heterobáricas, buscando associar a presença/ausência de EBF com o porte das plantas e com o ambiente. Quadrantes de 20mX20m foram demarcados nas fragmentos vegetacionais. Folhas completamente expandidas foram coletadas de 59 espécies no cerradão (32 arbóreas; 19 arbustos e 8 herbáceas); 68 espécies no cerrado stricto sensu (21 arbóreas; 30 arbustos e 17 herbáceas) e 51 espécies na floresta estacional ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In leaves of several plants species, the vascular bundle sheath extends toward the epidermis on both sides of the blade forming bundle sheath extensions (BSE), characterizing heterobarics leaves. Leaves lacking BSE are called homobarics. Research shows that homobaric leaves provide greater lateral movements of gases, while the BSE can act conducting water and increasing the leaf photosynthetic performance, what ensures the transference of light to the inner layers of the mesophyll. The morphological and functional differences between the two leaf types seem to be related to the environment where the plants occur and their distribution in the different vegetation strata. However, there are no studies on the distribution of species with homobarics and heterobarics leaves for vegetation formations in Brazil. This work aimed to study the leaf anatomy of herbs, shrubs and trees in semideciduous seasonal forest, cerradão and cerrado stricto sensu to identify homobarics and heterobarics leaves, searching to associate the presence / absence of BSE to the plant strata and environmental characteristics. Quadrants of 20mX20m were marked in vegetation fragments. Fully expanded leaves were collected from 59 species in the cerradão (32 tree, 19 shrubs and 8 herbs); 68 species in the cerrado stricto sensu (21 tree, 30 shrubs and 17 herbs) and 51 species in the semideciduous seasonal forest (23 tree, 17 shrubs and 11 herbs). Samples of the leaf blade were processed according to standard tech... (Complete abstract click electronic access below) / Mestre

Group of specialized cells that form cardiac conduction system is responsible for generation and coordinated propagation of the electrical impulse in the heart. Changes in its development can be connected with arrhythmias; therefore, a good level of knowledge is necessary and relevant for basic science and clinical practice. For correct development of the conduction system are important genes coding gap junctions proteins, ion channels, transcription factors and other molecules involved in signaling cascades (endothelin, neuregulin). Development of conduction system is determined in addition to genetic factors also by epigenetics and environmental factors. This thesis with its individual papers on which it is based is addressing different aspects of conduction system development, which appears to be a complex process. Another feature which is linking all papers together, is the methodological approach enabling us to study function of the conduction system - optical mapping. In the first publication we studied by the means of in vitro organ culture the impact of work load without interfering hemodynamics on the conduction system maturation in the chick embryonic heart. The phenotype observed during experiments was developmental regression of conduction system maturation together with changes in...

Presence of left bundle branch block (LBBB), regardless of evidence of heart disease, increases cardiovascular mortality and morbidity. Isolated LBBB induces ventricular septal asynchrony, it can cause repercussions in left ventricular (LV) function and diameter, which may evolve into ventricular remodeling and heart failure. Cardiopulmonary exercise test (CPET) is a noninvasive diagnostic method and physiological, that simultaneously evaluates cardiovascular and respiratory functions, fundamental to understanding the mechanisms of exercise limitation.. This study sought to evaluate the implications of isolated LBBB to cardiovascular performance in patients with preserved LV systolic function and absence of myocardial ischemia. This is an observational, cross-sectional analysis, which evaluated 02 groups: LBBB (26 patients) and control (23 patients). All patients showed LV systolic function > 50% and myocardial ischemia was excluded through the physical stress echocardiography. They underwent CPET. At statistical analysis, we chose the general linear model, specifically multivariate analysis of covariance (MANCOVA) in which the dependent variables were the parameters of CPET and fixed factors were the LBBB and sedentary lifestyle. The results showed that the percentage of predicted peak oxygen pulse (O2P) in the LBBB group was 98.6 ± 18.6% versus 109.9 ± 13.5% (p = 0.02); the percentage of predicted peak oxygen consumption (VO2) in patients with LBBB was 87.2 ± 15.0% versus 105.0 ± 15.6% (p <0.0001); the percentage of predicted anaerobic threshold VO2 in LBBB group was 67.9 ± 13.6 % versus 70.2 ± 12.8% (p = 0.55); in the LBBB group, ΔVO2/Δwork rate was 15.5 ± 5.5 ml.min-1.watts-1 versus 20.7 ± 7.3 ml.min-1.watts-1 (p = 0.006); the VE/VCO2 slope in LBBB group was 29.8 ± 2.9 versus 26.2 ± 2.9 (p = 0.0001) and T1/2 VO2 was the LBBB group of 85.2 ± 11.8 seconds versus 71.5 ± 11.0 seconds (p = 0.0001). By MANCOVA, adjusting the intervention of sedentary lifestyle and covariates, it was showed that patients with LBBB with preserved left systolic function and absence of myocardial ischemia, showed increase in the VE/VCO2 slope, but the LBBB did not affect aerobic performance. Further studies are needed to elucidate whether the VE/VCO2 slope will be an earlier marker of ventricular dysfunction in patients with LBBB. / A presença de bloqueio do ramo esquerdo (BRE), independente da evidência de cardiopatia, está associado ao aumento da mortalidade e morbidade cardiovascular. O BRE isolado provoca assincronia do septo interventricular, causando repercussões nos diâmetros e na função do ventrículo esquerdo (VE), que podem progredir para o remodelamento ventricular e insuficiência cardíaca. O teste de esforço cardiopulmonar (TECP) é um método diagnóstico não invasivo e fisiológico, avalia simultaneamente as funções cardiovascular e pulmonar, permitindo entender melhor as causas da limitação ao exercício. O presente estudo buscou avaliar as implicações do BRE isolado no desempenho cardiovascular de pacientes com função sistólica do VE preservada e na ausência de isquemia miocárdica. Trata-se de um estudo observacional, transversal e analítico, que avaliou 02 grupos: BRE (26 pacientes) e controle (23 pacientes). Todos os pacientes apresentavam fração de ejeção do VE (FEVE) > 50%, pelo método Simpson e a pesquisa de isquemia do miocárdio foi realizada por meio da ecocardiografia sob estresse físico. Todos os pacientes foram submetidos ao TECP. Na análise estatística, optou-se pelo modelo linear geral, particularmente análise multivariada de covariância (MANCOVA), em que as variáveis dependentes foram os parâmetros do TECP e os fatores fixos foram o BRE e o sedentarismo. Os resultados revelaram que a percentagem atingida do pulso de oxigênio (PO2) pico predito no grupo BRE foi de 98,6 ± 18,6% versus 109,9 ± 13,5%, (p = 0,02); a percentagem do consumo de oxigênio (VO2) pico predito nos portadores de BRE foi de 87,2 ± 15,0% versus 105,0 ± 15,6% (p < 0,0001); a percentagem do VO2 predito limiar anaeróbico no grupo BRE foi de 67,9 ± 13,6 % versus 70,2 ± 12,8% (p = 0,55); o ΔVO2/Δcarga no grupo BRE foi de 15,5 ± 5,5 ml.min-1.watts-1 versus 20,7 ± 7,3 ml.min-1.watts-1(p = 0,006); a relação Ve/VCO2 slope no grupo BRE foi de 29,8 ± 2,9 versus 26,2 ± 2,9 (p = 0,0001) e o T1/2 VO2 no grupo BRE foi de 85,2 ± 11,8 segundos versus 71,5 ± 11,0 segundos (p = 0,0001). Através da MANCOVA, ajustando-se a intervenção do sedentarismo e das co-variáveis, mostrou-se que os portadores de BRE, com FEVE preservada e na ausência de isquemia miocárdica, apresentaram aumento do Ve/VCO2 slope, porém o BRE não provocou alteração da capacidade aeróbica. Novos estudos serão necessários para elucidar se o Ve/VCO2 slope será marcador precoce de disfunção ventricular nos portadores de BRE.

Nous traitons ici de questions d’effectivité dans les problèmes de Mordell-Lang et de Schanuel où la notion de hauteur algébrique joue un rôle central.Dans un premier temps nous revisitions la méthode de Vojta-Faltings dans un cadre général, en y incluant notamment un procédé de descente uniforme qui permet d’optimiser le nombre de recours au pesant mécanisme d’approximation diophantienne. Nous proposons ensuite une application de ce résultat au problème de Mordell-Lang plus Bogomolov dans le tore, qui consiste à décrire un sousensemble algébrique X comme réunion de translatés de sous-tores inclus dans X moyennant de se restreindre à un sous-groupe de rang fini épaissi. Nous nous appuyons en particulier sur un énoncé d’Amoroso et Viada concernant le problème de Bogomolov dans ce contexte et améliorons les bornes antérieures obtenues par Rémond.Dans un second temps, nous établissons une version du théorème de Schanuel dans le cadre d’un espace adélique hermitien sur un corps de nombres. Nous donnons une estimation asymptotique du nombre de points projectifs de hauteur bornée pour une hauteur définie par une famille de normes sur les complétés en chaque place, vérifiant certaines conditions mais sans hypothèse de pureté dans le cas ultramétrique. Le terme reste obtenu est totalement explicite et linéaire en le régulateur du corps de nombres grâce au recours à une méthode introduite par Schmidt. Nous traitons également plusieurs applications de ce résultat, notamment aux problèmes de Dedekind-Weber et de Loher-Masser. / We are dealing here with effectiveness matters about the Mordell-Lang and Schanuel problems where algebraic heights play a central role.At the first time, we modify the Vojta-Faltings method in a general context by including some uniform descending process which has the advantage to optimize the number of iterations of the heavy Diophantine approximation mechanism. We then propose an application to the toric Mordell-Lang plus Bogomolov problem whose aim is to describe an algebraic subset X as the union of translates of closed, irreducible subgroups included in X when restricted to some enlarged, finite rank subgroup. In particular we use a theorem of Amoroso and Viada about the Bogomolov problem in this context and we improve the previous bound given by Rémond.At the second time, we prove a version of the theorem of Schanuel in the setting of a Hermitian adelic vector bundle over a number field. We give an asymptotic estimate for the number of projective points of bounded height for heights given by a family of norms over the completions at each place, satisfying several conditions but no purity hypothesis in the ultrametric case. The error term is totally explicit and linear with respect to the regulator of the number field through the use of Schmidt’s method. We finally give some applications of our result in particular to the Dedekind-Weber and Loher-Masser problems.