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La réalisation par des procédés robotisés de pièces composites à destination, notamment, de l’aéronautique vise à en augmenter la productivité. Cependant le Placement de Fibres Robotisé (PFR) est encore en phase de maturation et requiert de nombreux développements, en particulier dans le cas des composites à matrice thermoplastique ou à fibre sèche. Dans cette thèse, nous proposons différents outils qui permettent in fine de déterminer à l’avance la meilleure puissance de chauffe pour la mise en œuvre de ces composites. La difficulté réside dans le fait que cette puissance dépend de nombreux paramètres, non seulement au niveau de la matière utilisée (densité, chaleur spécifique. . .), mais encore au niveau du procédé lui-même (vitesse de déplacement, nombre et orientation des plis. . .). Nous avons construit un modèle réduit multi-paramétrique en utilisant la technique appelée Proper Generalised Decomposition (PGD). Les résultats ont été confrontés à ceux obtenus par des méthodes plus conventionnelles et aussi à des données expérimentales. / Realising composite parts mainly dedicated to aeronautics sector by robotised processes tends to increase productivity. However, Automated Tape Placement (ATP) is still in ripening stage and requires various developments, particularly in case of thermoplastic composites or dry fibres. In this manuscript, we propose different tools allowing to determine in advance the best heating power to drape composite fibres. Difficulty arises from dependence on many parameters, from material (density, specific heat) or from process itself (velocity, number and orientation of plies). Therefore we construct a multi-parametric reduced order model using the so called Proper Generalised Decomposition (PGD). Results have been faced to those obtained from more conventional methods but also to experimental data.

Made available in DSpace on 2015-05-15T11:46:16Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 713593 bytes, checksum: 9a4eca1dfe2fca22fc63a3364773af08 (MD5) Previous issue date: 2013-09-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Cook's local infuence approach based on normal curvature is an important diagnostic tool for assessing local infuence of minor perturbations to a statistical model. However, no rigorous approach has been developed to address two fundamental issues: the selection of an appropriate perturbation and the development of infuence measures for objective functions at a point with a nonzero rst derivative. The aim of this paper is to develop a diferential-geometrical framework of a perturbation model (called the perturbation manifold) and utilize associated metric tensor and ane curvatures to resolve these issues. We will show that the metric tensor of the perturbation manifold provides important information about selecting an appropriate perturbation of a model. / A Abordagem de influência local de Cook [2] com base em curvatura normal é uma importante ferramenta de diagnóstico para avaliar a influência local de pequenas perturbações de um modelo estatístico. No entanto, tem sido desenvolvida nenhuma abordagem rigorosa para abordar duas questões fundamentais: a escolha de uma perturbação apropriada e o desenvolvimento de medidas de influência para funções objetos em um ponto com a primeira derivada diferente de zero. O objetivo deste trabalho é desenvolver uma estrutura diferencial-geométrica de um modelo de perturbação (chamado de variedade de perturbação) e utilizar o tensor métrico associado e as curvaturas afins para resolver esses problemas. Vamos mostrar que o tensor métrico da variedade de perturbação fornece informações importantes sobre a seleção de uma perturbação apropriada de um modelo.

Made available in DSpace on 2015-05-15T11:46:23Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 490053 bytes, checksum: c9cf689fde66aed86d7eb372eeb05045 (MD5) Previous issue date: 2009-05-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Cook's local infuence approach based on normal curvature is an important diagnostic tool for assessing local infuence of minor perturbations to a statistical model. However, no rigorous approach has been developed to address two fundamental issues: the selection of an appropriate perturbation and the development of infuence measures for objective functions at a point with a nonzero first derivative. The aim of this paper is to develop a diferential-geometrical framework of a perturbation model (called the perturbation manifold) and utilize associated metric tensor and affine curvatures to resolve these issues. We will show that the metric tensor of the perturbation manifold provides important information about selecting an appropriate perturbation of a model. / Esta dissertação é dedicada ao estudo do sistema de Navier-Stokes sob ponto de vista da teoria do controle. Primeiramente estudamos a controlabilidade das aproximações de Galerkin do sistema de Navier-Stokes. Utilizando argumentos de dualidade e de ponto fixo, mostramos que, com hipóteses adequadas sobre a base de Galerkin, estas aproximações, finito dimensionais, são exatamente controláveis. Passando ao modelo em dimensão infinita, analisamos a controlabilidade sobre trajetórias. Isto é feito usando uma desigualdade do tipo Calerman para o sistema de Navier-Stokes linearizado e uma versão do teorema da função inversa. Dessa forma, temos um resultado de controlabilidade local exata para o sistema de Navier-Stokes.

Nous présentons dans cette étude nos travaux concernant le recalage 3D/2D d'images de dissection aortique. Son but est de de proposer une visualisation de données médicales, qui pourra servir dans le contexte de l'assistance peropératoire durant les procédures endovasculaires.Pour effectuer cette tâche, nous avons proposé un modèle paramétrique de l'aorte, appelé enveloppe tubulaire. Il sert à exprimer la forme globale et les déformations de l'aorte, à l'aide d'un nombre minimal de paramètres.L'enveloppe tubulaire est utilisée par les algorithmes de recalage proposés dans cette étude.Notre méthode originale consiste à proposer un recalage par calcul direct de la transformation entre image 2D, i.e. sans procéssus d'optimisation, et est appelée recalage par ITD .Les descripteurs, que nous avons définis pour le cas des images d'aorte, permettent de trouver rapidement un alignement grossier des données. Nous proposons également l'extension de notre approche pour la mise en correspondance des images 3Det 2D.La chaîne complète du recalage 3D/2D, que nous présentons dans ce document, est composée de la technique ITD et de méthodes précises iconiques et hybrides. L'intégration de notre algorithme basé sur les descripteurs en tant qu'étape d'initialisation réduit le temps de calcul nécessaire et augmente l'efficacité du recalage, par rapport aux approches classiques.Nous avons testé nos méthodes avec des images médicales, issues de patients trîtés par procédures endovasculaires. Les résultats ont été vérifiés par les spécialistes cliniques et ont été jugés satisfaisants; notre chaine de recalage pourrait ainsi être exploitée dans les salles d'interventions à l'avenir. / In this study, we present our works related to 3D/2D image registrationfor aorti dissition. Its aim is to propose a visualization of medial datawhih an be used by physians during endovas ular proedures.For this purpose, we have proposed a parametrimodel of aorta, alleda Tubular Envelope. It is used to express the global shape and deformationsof the aorta, by a minimal number of parameters. The tubular envelope isused in our image registration algorithms.The registration by ITD (Image Transformation Descriptors) is our ori-ginal method of image alignment : itomputes the rigid 2D transformation between data sets diretly, without any optimization process.We provide thedefinition of this method, as well as the proposition of several descriptors' formulae, in the base of images of aorta. The technique allows us to quickly and a poarse alignment between data. We also propose the extension of theoriginal approach for the registration of 3D and 2D images.The complete chain of 3D/2D image registration techniques, proposedin this document, consists of the ITD stage, followed by an intensity basedhybrid method. The use of our 3D/2D algorithm, based on the image trans-formation descriptors as an initialization phase, reduces the computing timeand improves the efficiency of the presented approach.We have tested our registration methods for the medical images of several patients after endovasular treatment. Results have been approved by our clinical specialists and our approach.We have tested our registration methods for the medical images of several patients after endovascular treatment. Results have been approved by our clinical specialists and our approach may appear in the intervention rooms in the futur.

The subject of this master’s thesis is the design of an autonomous snow groomer intended for the treatment of well-geodetically mapped slopes of ski resorts. Designed design uses an innovative approach to detecting the thickness of a snow cover by an electromagnetic sensor system. The work identifies and presents the concept of solving specific problems of autonomous operation in ski areas, in the form of a design vision. This concept is presented and verified using a parametric model.

This theses is related to design of synchronous reluctance motors of the transverse-laminated type. The first part describes synchronous reluctance machine via space-vector theory. Furthermore this part briefly discuss the main design aspects of synchronous reluctance machines. The main part of this thesis is related to practical electromagnetic rotor design for synchronous reluctance machine by means of finite element method. On this base the rotor has been fabricated and placed inside of induction motor instead of his original rotor. On this prototype was made several measurements which were compared with results from finite element method analysis. The last part of this theses is related to short study of synchronous reluctance machine dynamical behaviour under scalar and vector control.

Le concept de gouvernance appréhendée par la Banque mondiale au milieu des années 1980, apparaît comme une préoccupation majeure au niveau de l’analyse du développement économique. Il est de plus en plus présent dans les débats sur la recherche de solides fondements de la croissance économique, notamment la croissance économique de long terme dans les pays en voie de développement. La résurgence de la pauvreté après la mise en œuvre des programmes d’ajustement structurel, la persistance des inégalités en Afrique subsaharienne, l’importance des ressources naturelles dont dispose ces pays, et la volonté manifestée récemment par les Chefs d’Etat de ces pays, d’engager leurs pays respectifs à l’initiative de transparence dans les industries extractives (ITIE), suscitent de nombreux enjeux, auxquels seule leur capacité à conduire la bonne gouvernance leur mettra en position de réaliser une croissance économique capable de réduire les inégalités. L’objectif principal de cette thèse est d’analyser le rôle des institutions dans la détermination de la croissance économique en Afrique au Sud Sahara et en diagnostiquant l’influence d’autres variables anthropo-sociologiques telle que la fragmentation ethnique sur la trajectoire de la croissance économique. En utilisant des techniques économétriques et statistiques adéquates et pertinentes, nous arrivons dans un premier temps à montrer qu’il existe une relation positive et très significative entre l’ensemble des variables de gouvernance (Ecoute des citoyens et reddition des comptes ; Stabilité politique et absence de violence ; Efficacité des pouvoirs publics ; Qualité de la réglementation ; Règle de Loi ou Etat de droit ; Maitrise de la corruption) et le taux de croissance du PIB par tête des pays en Afrique au Sud du Sahara. De plus, Cette croissance du PIB par tête est beaucoup plus importante pour les pays colonisés par l’Angleterre et moins favorable pour ceux colonisés par la France. On est tenté à ce stade de l'analyse de lier la qualité des institutions des pays africains à celle des pays colonisateurs. Dans un second temps, l’étude a révélé qu’il n’y a pas de relation linéaire entre le taux de croissance du PIB par tête et les variables mises en évidence. De plus, en présence de la variable« Ethnie », les variables de gouvernance n’ont pas d’influence fondamentale sur la croissance économiquedes pays en Afrique au Subsaharienne. Néanmoins, une relation positive et très significative entre la variable « Ethnie » et le taux de croissance du PIB par tête a été mise en évidence. Enfin, ce travail nous a permis d’apprécier la qualité des institutions et des systèmes de contre-pouvoir notamment l’implication des Organisations de la Société Civile dans la définition et la mise en œuvre des politiques et programmes de développement au Tchad à partir de l’analyse de l’état de la gouvernance économique et financière. / The concept of governance initiated by the World Bank in the mid-1980s appears to be a major concern in the analysis of economic development. It is increasingly present in the debate on finding a solid foundation for economic growth, particularly long-term economic growth in developing countries. The resurgence of poverty following the implementation of structural adjustment programs, the persistence of inequality in sub-Saharan Africa, the abundance of natural resources available to these countries and the clear willingness lately shown by the Heads of State of these countries, to commit their respective countries to the Extractive Industries Transparency Initiative (EITI), raise many issues, to which only their capacity to upload good governance will enable them to attain an economic growth that can reduce levels of inequality. The main objective of this thesis is to analyze the role of institutions in determining economic growth in Africa South Sahara and diagnosing the influence of other anthropological - sociological variables such as ethnic fractionalization in the path of the economic growth. Using appropriate econometric techniques and relevant statistics, we reach first to show that there is a positive and highly significant relationship between all governance variables (Citizen Voices and Accountability, Political Stability and Absence of Violence, Government Effectiveness, Regulatory Quality, Rule of Law or State of Law, Control Corruption) and the GDP growth rate per capita of the countries in Africa south of the Sahara. In addition, the growth of GDP per capita is much more important for countries colonized by England and less favorable to those colonized by France. One is tempted at this stage of the analysis to link the quality of the institutions of the African countries to that of the colonizing countries. Secondly, the study found that there is no linear relationship between the growth rate of GDP per capita and variables highlighted. Moreover, in the presence of the variable " Ethnic ", the governance variables do not have a fundamental influence on economic growth of the countries in Sub-Saharan Africa. Nevertheless, a positive and highly significant relationship between the variable " Ethnic " and the GDP growth rate per capita was highlighted. Finally, this work has allowed us to appreciate the quality of institutions and systems against power including the involvement of civil society organizations in the definition and implementation of the development of policies and programs in Chad from the analysis of the state of the economic and financial governance.

A reação álcali-agregado (RAA) é uma reação química complexa envolvendo os álcalis presentes no cimento Portland e minerais silicosos presentes em alguns tipos de agregados reativos. O produto dessa reação expande quando em contato com a água, causando fissuração e deformação, o que afeta a durabilidade e importantes propriedades mecânicas das estruturas de concreto. Entretanto, estruturas que estejam sob tensão de compressão, aplicada por carregamentos ou induzida pela presença de armadura, apresentam expansão reduzida na direção comprimida. Uma das ferramentas que se utiliza para a previsão da vida útil de estruturas afetadas pela RAA é a modelagem numérica da expansão do concreto, possibilitando a previsão e projeto de reparos necessários. Nesse contexto, modelos paramétricos combinam os principais fatores que influenciam a reação (reatividade dos constituintes, porosidade, temperatura, umidade e estado de tensões), possibilitando a determinação da distribuição e da taxa de expansão na estrutura. Nessa pesquisa foi desenvolvido um modelo paramétrico cujo principal interesse foi o estudo das tensões induzidas pela presença de fibras e armadura na expansão do concreto afetado pela RAA. O modelo implementado em elementos finitos tem como parâmetros nodais as posições, uma formulação alternativa ao método dos elementos finitos baseado em deslocamentos; a medida de deformação utilizada é a de Green e a lei constitutiva dos materiais é a de Saint-Venant-Kirchhoff. O material composto é discretizado por meio de uma matriz elástica bi-dimensional reforçado por fibras lineares perfeitamente aderidas à matriz. Comparações entre os resultados obtidos por meio do modelo desenvolvido e resultados de trabalhos experimentais comprovam a aplicabilidade e potencialidade do modelo numérico apresentado. / The alkali-aggregate reaction (AAR) is a complex chemical reaction involving alkalis present in the Portland cement paste and siliceous minerals present in some types of reactive aggregates. The product of this reaction expands in contact with water, causing cracking and deformation that affects durability and important mechanical properties of the concrete structures. However, structures under compressive stress, applied or induced by the presence of rebars, the expansion is reduced in the compressed direction. One of the tools used to predict the service life of structures affected by AAR is the numerical modeling of the concrete expansion, allowing prevision and projecting repairs needed. In this context, parametric models combine the main factors that influence the reaction (reactivity of the constituents, porosity, temperature, humidity and stress state), enabling the determination of distribution and rate of expansion in the structure. In this research was developed a parametric model whose main interest was the study of stresses induced by the presence of fibers and rebars in the expansion of concrete affected by AAR. The model implemented in finite element has as nodal parameters positions, an alternative formulation to the finite element method based on displacement; the deformation measurement used is Green and the material constitutive law is the Saint-Venant-Kirchhoff. The composite material is discretized by a two-dimensional elastic matrix reinforced by perfectly adherent linear fibers. Comparisons between the results obtained from the developed model and results of experimental studies demonstrate the applicability and potential of the numerical model presented.

Στην παρούσα διατριβή αναπτύσσεται ένα ολοκληρωμένο μεθοδολογικό πλαίσιο για την ανάλυση της παραγωγικής αποτελεσματικότητας επιχειρήσεων που λειτουργούν σε περιβάλλον πολλαπλής τεχνολογικής ετερογένειας. Με βάση την έννοια των μετα-μεταορίων, ορίζονται μέτρα αποτελεσματικότητας και τεχνολογικών χασμάτων σε κάθε επίπεδο τεχνολογικής ετερογένειας, τα οποία, σε ένα δεύτερο στάδιο, «αποδομούνται» σε παράγοντες σταθερούς ως προς τις εισροές και παράγοντες σταθερούς ως προς τις εκροές. Η προτεινόμενη μεθοδολογία χρησιμοποιείται για την διερεύνηση της παραγωγικής αποτελεσματικότητας των ευρωπαϊκών τραπεζικών επιχειρήσεων, λαμβάνοντας υπόψη πιθανή τεχνολογική ετερογένεια που οφείλεται στα ιδιαίτερα χαρακτηριστικά (i) των εθνικών τραπεζικών συστημάτων και (ii) των τραπεζικών τύπων ειδίκευσης. Οι επιδράσεις των εν λόγω πηγών τεχνολογικής ετερογένειας στην τραπεζική αποτελεσματικότητα εξετάζονται ξεχωριστά, σε ένα πλαίσιο ανάλυσης τεχνολογικής ετερογένειας ενός επιπέδου, και συνδυαστικά, σε ένα πλαίσιο ανάλυσης ιεραρχημένης τεχνολογικής ετερογένειας δύο επιπέδων. Τα αποτελέσματα της σχετικής εμπειρικής ανάλυσης ερμηνεύονται με βάση την «θεωρία της γνώσης», δίνοντας ιδιαίτερη έμφαση στον ρόλο της διάχυσης της γνώσης, της ικανότητας απορρόφησης και του στρατηγικού προσανατολισμού των ευρωπαϊκών τραπεζικών επιχειρήσεων. / In the context of the present thesis, a methodological framework is developed for analysing the productive efficiency of firms that operate in a multilevel technologically heterogeneous environment. Based on the meta-metafrontier notion, efficiency and technology gaps measures are defined at each level of technology heterogeneity and are decomposed into input- and output-invariant components. The proposed methodology is used for the investigation of productive efficiency of European banking firms, taking into account potential technology heterogeneity due to the particular characteristics of (i) the national banking systems and (ii) the specialization types of banking firms. The effects of the aforementioned heterogeneity sources on bank efficiency are examined separately, in a single-level technology heterogeneity framework, and simultaneously, in a hierarchical technology heterogeneity framework of two levels. The results of the relevant empirical analysis are interpreted using the “knowledge-based theory”, emphasising on the role of knowledge spillovers, the banking firms’ absorptive capacity and strategic orientation.