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La plupart des méthodes de surveillance des systèmes sont basées sur l'analyse et la caractérisation de grandeurs physiques qui sont par nature tridimensionnelles. Tracées dans un repère euclidien à trois dimensions, ces grandeurs parcourent en fonction du temps une trajectoire dont les caractéristiques géométriques sont représentatives de l'état du système surveillé. Les techniques classiques de surveillance des systèmes étudient les grandeurs mesurées composante par composante, sans prendre en compte leur nature tridimensionnelle et les propriétés géométriques de leur trajectoire. Une part importante de l'information est ainsi ignorée. Dans le cadre de ce travail de recherche, on se propose de développer une méthode d'analyse et de traitement de grandeurs à trois composantes permettant de mettre en évidence les spécificités géométriques des données et de fournir une information complémentaire pour la surveillance des systèmes. La méthode proposée a été appliquée à deux cas différents : la surveillance des creux de tension des réseaux de puissance triphasés et la surveillance des défauts de roulement des machines électriques tournantes. Dans ces deux cas, les résultats obtenus sont prometteurs et montrent que les indicateurs géométriques estimés mènent à de l'information complémentaire qui peut être utile pour la surveillance des systèmes. / Most methods for condition monitoring are based on the analysis and characterization of physical quantities that are three-dimensional in nature. Plotted in a three-dimensional Euclidean space as a function of time, these quantities follow a trajectory whose geometric characteristics are representative of the state of the monitored system. Usual techniques of condition monitoring study the measured quantities component by component, without taking into account their three-dimensional nature and the geometric properties of their trajectory. A significant part of the information is thus ignored. In this research work, we would therefore like to develop a method for the analysis and processing of three-component quantities capable of highlighting the special geometric features of such data and providing complementary information for condition monitoring. The proposed method has been applied to two different cases: voltage dips monitoring in three-phase power networks and bearing faults monitoring in rotating electrical machines. In this two cases, the results obtained are promising and show that the estimated geometric indicators lead to complementary information that can be useful for condition monitoring.

Les travaux présentés dans cette thèse sont réalisés dans le cadre du projet européen ACCENT et s’inscrivent dans la problématique de l’utilisation de la surveillance d’usinage dans la fabrication des pièces critiques de moteurs aéronautiques. L’objectif est de définir une technique de surveillance de l’usure de l’outil dans l’usinage de l’alésage central d’un disque haute pression réalisé en superalliage à base nickel. Trois grandes étapes peuvent être identifiées dans notre démarche : l’identification des modes de dégradation dans le perçage de l’Udimet® 720 LI, la définition de relations entre les différents types d’usure et les grandeurs physiques mesurées et finalement, la proposition de stratégies de surveillance basées sur les résultats précédents. Afin de répondre aux objectifs, un protocole expérimental a été défini. Les campagnes expérimentales nous ont permis de caractériser l’usure du foret et de définir une cartographie des modes de dégradation en fonction de conditions de coupe testées. Par ailleurs, l’impact des perturbations d’usinage (coupure de lubrification, modification du pourcentage d’émulsion du lubrifiant, défaut de position de l’outil par rapport à l’avant-trou, etc.) a été étudié. La deuxième partie consiste à identifier les relations entre les modes de dégradation et les signaux de surveillance enregistrés (efforts, couple, puissance, vibrations, etc.). Pour cela, nous avons privilégié deux pistes : une explication directe de l’évolution des signaux par des phénomènes physiques et une approche selon « la base de données », pour développer des modèles d’usures par des critères statistiques extraits sur les signaux. Cette analyse a aussi permis la détection de certaines perturbations d’usinage en utilisant les grandeurs physiques mesurées. Il s’agit notamment d’un défaut d’excentration de l’outil dans le porte-outil et d’un problème d’évacuation de copeaux. La troisième étape porte sur la sensibilité des signaux afin de détecter l’ensemble des phénomènes et la définition des stratégies de surveillance pouvant être mises en œuvre. Pour chaque relation définie, nous avons déterminé une probabilité de détection. Ensuite, nous avons utilisé les signaux en parallèle afin d’accroitre la robustesse de la détection. Les taux de probabilité ont été améliorés, en se basant sur l’hypothèse d’indépendance des signaux (sans calculer les biais existants). Enfin, l’association de l’approche phénoménologique à l’approche dite « statistique » a permis d’augmenter la robustesse de la surveillance. / The work presented in this thesis is a part of European project ACCENT and fits into the context of using process monitoring in the manufacture of critical parts for aircraft engines. The aim is to define a monitoring technique for the tool wear in the machining of the central bore of a high pressure disk made in nickel based superalloy. The major stages can be identified in our approach: identification of tool failure modes in drilling Udimet® 720 LI, defining the relationships between wear and measured physical quantities and finally, a proposal for monitoring strategies based on the previous results. In order to complete the objectives, an experimental protocol was defined. The experimental campaigns allowed us to characterize the drill wear and to define cartography of tool failure modes depending on cutting conditions tested. Moreover, the impact of machining disturbances (lubricant stop, change in percentage of lubricant emulsion, the position over the before hole, etc.) was studied. In the second part, the relations between the tool failure modes and monitoring signals recorded during the machining (forces, torque, power, vibrations, etc.) were identified. For this task, we focused on two directions: a straightforward explanation of signals evolution by physical phenomena and “black box” approach to develop wear models from a database obtained by statistical criteria extracts from the signals. This analysis also allowed the detection of certain machining disturbances using the physical quantities. These include an eccentricity of the tool in the tool holder and a chips evacuation problem. The third part concerns the signals sensitivity to detect the different phenomena and the definition of monitoring strategies which can be implemented. For each relation defined, a detection probability was determined. Further, we used signals in parallel to increase the robustness of detection. The probabilities were improved, with an assumption of independent signals (without calculating existing biases). Finally, the combination of the phenomenological approach to the so-called "statistical" has increased the robustness of the monitoring technique.

Cette thèse porte sur l’homogénéisation quantitative d’équations aux dérivées partielles paraboliques, et de problèmes elliptiques discrets. Dans l’introduction, nous voyons comment de tels problèmes, même lorsque les coefficients sont déterministes, résultent d’un modèle aléatoire. Nous donnons ensuite une notion de ce qu’est l’homogénéisation : que se passe-t-il lorsque les coefficients eux-mêmes sont aléatoires, est-il possible de considérer qu’un environnement présentant des inhomogénéités sur de très petites échelles, se comporte d’une manière proche d’un environnement fictif qui serait homogène ?Nous donnons ensuite une interprétation de cette question en terme de marche aléatoire en conductances aléatoires, puis donnons une idée des outils utilisés dans les preuves des deux chapitres suivants. Dans le chapitre II, nous démontrons un résultat d’homogénéisation quantitative pour une équation parabolique – l’équation de la chaleur par exemple – dans un environnement admettant des coefficients aléatoires et dépendant du temps. La méthode utilisée consiste à considérer les solutions d’un tel problème comme optimiseurs de fonctionnelles qui seront définies au préalable, puis d’utiliser la propriété cruciale de sous-additivité de ces quantités, afin d’en déduire une convergence puis un résultat de concentration, qui permettra d’en déduire une vitesse de convergence des solutions vers la solution du problème homogénéisé, Dans le chapitre III, nous adaptons ces méthodes pour un problème elliptique sur le graphe Zd. / This thesis deals with quantitative stochastic homogenization of parabolic partial differential equations, and discrete elliptic problems. In the introduction, we see how can such problems come from random models, even when the coefficients are deterministic. Then, we introduce homogenization : what happen if the coefficients themselves are random ? Could we consider that an environment with microscopical random heterogeneities behaves, at big scale, as a fictious deterministic homogeneous environment ? Then, we give a random walk in random environment interpretation and the sketch of the proofs in the two following chapters. In chapter II, we prove a quantitative homogenization result for parabolic PDEs, such as heat equation, in environment admitting time and space dependent coefficients. The method of the proof consists in considering solutions of such problems as minimizers of variational problems. The first step is to express solutions as minimizers, and then to use the capital property of subadditivity of the corresponding quantities, in order to deduce convergence and concentration result. From that, we deduce a rate of convergence of the actual solutions to the homogenized solution. In chapter III, we adapt these methods to a discrete elliptic problem on the lattice Zd.

Made available in DSpace on 2014-06-11T19:22:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-11-08Bitstream added on 2014-06-13T18:08:33Z : No. of bitstreams: 1 semensato_m_me_ilha.pdf: 1302035 bytes, checksum: 43c8881f259cd513c7fc585dd25d1307 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho tem o objetivo de abordar a Teoria da Potência Complexa Instantânea, a qual utiliza vetores espaciais instantâneos, e mostrar sua utilidade através de duas aplicações para cargas do sistema trifásico: A ponte retificadora trifásica de seis pulsos e o transitório de partida de um motor de indução trifásico. Os resultados obtidos são comparados com as grandezas de Buchholz-Goodhue no cálculo da potência aparente e do fator de potência, grandezas estas definidas na norma IEEEStd 1459/2000, para sistemas trifásicos operando em regime permanente em condições de desequilíbrio e com formas de onda não-senoidais. Mostra-se a sua utilidade para a análise destes dois sistemas e lança-se um pouco mais de entendimento da relação existente entre estas duas abordagens. A ponte retificadora trifásica é analisada em condições equilibradas, facilitando-se, portanto, a comparação com a teoria convencional para regimes equilibrados e não-senoidais. Com relação ao transitório de partida do motor de indução, fica evidenciado que este pode ser tratado como se estivesse operando em regime para cada valor do escorregamento, durante o período do transitório eletromecânico. / This work aims to show The Instantaneous Complex Power approach, which uses instantaneous space vectors, showing its usefulness through two applications: The six pulse three-phase bridge rectifier and the starting transient of an induction motor. The results are compared to the Buchholz-Goodhue quantities, as defined in IEEE-Std 1459/2000, which deals with three-phase power systems under non-sinusoidal and unbalanced conditions. In this way it is possible to improve our understanding of the theory and the Buchholz- Goodhue approach. As the three-phase bridge rectifier is analyzed under balanced conditions, it facilitates the comparison of these two approaches with the conventional power theory for this case. Concerning the induction motor, it is shown that it can be treated as operating on steady-state sinusoidal conditions for every value of its slip during the electromechanical period of the starting process.

Made available in DSpace on 2016-12-12T17:38:37Z (GMT). No. of bitstreams: 1 ILTON ANCELMO PEREIRA JUNIOR.pdf: 6854626 bytes, checksum: 8fdf9667f4e840b4dc298f1e9605bf2d (MD5) Previous issue date: 2011-02-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This master thesis introduces a study about the influence of frequency variation induced in the magnetic properties of materials. Experiments are accomplished in the Epstein frame or Epstein square, the measurements are being acquired through a data acquisition system PC-based, which is handled through a software developed in LabVIEW. As results, we have the magnetization curve, hysteresis loop and specific losses for several preset frequencies, and the harmonic distortion evaluation in current and voltage signals during the trial. The end of the essay presents a methodology able to accomplish the harmonics cancellation generated by the steel saturation, applying a voltage source having adjustable harmonic voltages. / Esta dissertação apresenta um estudo sobre a influência da variação da frequência nas propriedades magnéticas dos materiais. Os ensaios são realizados em quadro de Epstein, sendo as medições obtidas através de um sistema de aquisição de dados baseado em PC, o qual é controlado por um software desenvolvido em LabVIEW. Como resultados têm-se a curva de magnetização, a curva de histerese e as perdas específicas para diversas frequências pré-selecionadas, sendo avaliadas as distorções harmônicas de tensão e de corrente, durante os ensaios. Ao final é apresentada uma metodologia capaz de realizar o cancelamento das harmônicas geradas pela saturação do aço, através de uma fonte de tensão com ajuste de harmônicos.

Submitted by JEAN-JACQUES ARMAND VIDAL null (je.jacvi@yahoo.com.br) on 2017-05-17T01:26:09Z No. of bitstreams: 1 repositório Doutorado.pdf: 41703688 bytes, checksum: 81eff3f181fa51f11a08b3377f9188d4 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-05-17T12:34:53Z (GMT) No. of bitstreams: 1 vidal_jja_dr_ia.pdf: 41703688 bytes, checksum: 81eff3f181fa51f11a08b3377f9188d4 (MD5) / Made available in DSpace on 2017-05-17T12:34:53Z (GMT). No. of bitstreams: 1 vidal_jja_dr_ia.pdf: 41703688 bytes, checksum: 81eff3f181fa51f11a08b3377f9188d4 (MD5) Previous issue date: 2017-03-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este estudo propõe-se a apresentar a cerâmica de dois povos indígenas da Amazônia, os Paiter Suruí de Rondônia e os Asurini do Xingu. No caso dos Suruí, trata-se do ponto de vista dos homens, dois professores e lideranças, sobre o que representam na cultura Paiter Suruí as cerâmicas produzidas pelas ceramistas e sobre os desdobramentos de uma pesquisa feita em 2010 com as artistas Paiter Suruí (VIDAL, J., 2011). Para os Asurini, trata-se de uma pesquisa de campo e o estudo dos procedimentos de fabricação da cerâmica, as formas, os usos e a decoração dos vasilhames, tanto no ambiente domestico como ritualístico. Dá-se ênfase ao estudo dos grafismos pela sua importância nesta sociedade. Com base em quatro estudos recentes sobre cerâmica ameríndia (Karaja, Waúja, Palikur e Wayana) feitos por antropólogos, destaca-se a diversidade das produções cerâmicas indígenas e como ao longo da história pós contato elas passam por adaptações diversificadas, devido à comercialização dos artefatos produzidos. Tratamos de responder às perguntas: por que, como e em que condições a cerâmica indígena continua (ou não) a ser produzida? Por que ela resiste? / The aim of this paper is to present the pottery of two indigenous tribes of the Amazon, the Paiter Suruí from Rondônia, and the Asurini from Xingu. In the case of the Suruí tribe, it is considered the point of view of two men, two professors and leaders, showing what the pottery produced by the artisans represent to the Paiter Suruí culture, as well as the results of a research done in 2010 with the artisans in the Paiter Suruí tribe (VIDAL, J., 2011). For the Asurini, the approach is a field research as well as the analysis of the procedures for the manufacturing of the pottery, its shapes, the uses and the decoration of the containers, both in the domestic and the ritualistic environments. Emphasis is placed upon the study of the graphics due to its importance in that society. Based on four recent studies of the Amerindian pottery (Karajas, Waúja, Palikur and Wayana) carried out by anthropologists, one should highlight the diversity of the indigenous pottery production, and how it has gone through different adaptations throughout the post-contact history due to the commercialization of the items. We try to answer the questions: why, how and under what conditions is indigenous pottery still (or not) being produced? Why does it resist?

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-25T12:11:22Z No. of bitstreams: 1 camiladocarmoalmeida.pdf: 15878287 bytes, checksum: 7ce86267329e6481b097f64af841fe34 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-25T15:26:02Z (GMT) No. of bitstreams: 1 camiladocarmoalmeida.pdf: 15878287 bytes, checksum: 7ce86267329e6481b097f64af841fe34 (MD5) / Made available in DSpace on 2017-04-25T15:26:02Z (GMT). No. of bitstreams: 1 camiladocarmoalmeida.pdf: 15878287 bytes, checksum: 7ce86267329e6481b097f64af841fe34 (MD5) Previous issue date: 2014-08-29 / Este trabalho teve por objetivos projetar um sistema eletrônico de controle destinado a fornecer uma alternativa simplificada e eficiente para estudos de fisiologia vegetal envolvendo luz artificial, bem como para sua utilização em determinados processos de cultivo de plantas em estufas. O trabalho apresenta uma revisão sobre a interação entre a iluminação artificial e o cultivo de plantas, tanto para o propósito de uma cultura comercial quanto para possibilitar a interpretação do comportamento de plantas em estudos botânicos. Este sistema eletrônico possibilita a determinação das quantidades radiométricas de interesse quando a iluminação artificial é usada como suplemento ou como única fonte de iluminação em cultivos. Com base em estudos anteriores, é proposto a produção de um sistema autônomo constituído por um aparelho de iluminação composto por LEDs brancos e/ou coloridos. Além disso, foram realizados alguns experimentos radiométricos preliminares utilizando luminárias comerciais de LEDs, visando sua utilização em associação com o sistema de controle proposto. Os parâmetros medidos mais relevantes foram o fluxo de fótons fotossinteticamente ativos, fluxo luminoso e a temperatura de cor correlata. Espera-se que o protótipo desenvolvido apresente características que agreguem flexibilidade e comportamento radiométrico relevante para cultivos controlados. / This work aims to develop an electronic control system with the purpose to drive a simplified and efficient alternative for vegetal physiology studies involving artificial light as well as for its utilization in certain plants crop at greenhouses. Additionally, this work presents a brief review regarding the interaction between artificial lighting and plants, with purposes of commercial crops and the possibility of interpretation of plants behavior in botanic studies. This electronic system enables the determination of the radiometric quantities of interest when the lighting is used as a supplement or as the only lighting source in crops. Using the latest studies, it is proposed an autonomous system consisting basically of white and/or colored LEDs. Besides, it were performed radiometric experiences using commercial luminaires with LEDs aiming the use of them in the proposed control system. The more relevant measured parameters were the photosynthetic photon flux, luminous flux and correlated colour temperature. The proposed system shows flexibility and relevant radiometric behavior, which are particularly useful in Plant Physiology.

L'étude de l'écoulement turbulent au sein des passes à fentes verticales est nécessaire afin d'améliorer ces dispositifs de franchissement contenant des barrières physiques aux mouvements migratoires des poissons. En effet, les études menées sur les passes existantes ont montré leurs limites pour permettre le franchissement des petites espèces de poissons avec des faibles capacités de nage. L'objectif de notre étude est d'adapter l'écoulement turbulent dans la passe aux capacités de nage des poissons. Des mesures de vitesse bidimensionnelle par Vélocimétrie par Imagerie de Particules (PIV) et les mesures de vitesse tridimensionnelle par Vélocimétrie Acoustique par effet Doppler (ADV) ont montré que les grandeurs cinématiques de l'écoulement au sein des passes existantes sont très importantes et donc affectent les capacités de nages des petites espèces de poissons. Une des stratégies pour répondre à ce problème est d'introduire des obstacles de forme cylindrique au sein des bassins de la passe à poissons. L'insertion de ces cylindres a pour objectif de réduire les quantités cinématiques de l'écoulement turbulent au sein de la passe afin d'adapter cet ouvrage au passage des petites espèces de poissons. Cette stratégie nécessite une méthode d'optimisation afin de trouver l'emplacement idéal des cylindres à partir de simulations numériques de l'écoulement (logiciel Star-CD). / The turbulent flow study in vertical slot fishway is necessary to improve this crossing device containing physical barriers to fish migration. Effectively, studies of existing fishways have shown their limits to ensure the crossing of small fish species with weak swimming abilities. The objective of our study is to adapt the turbulent flow to the fish species swimming abilities. The two-dimensional velocity measurements by Particle Image Velocimetry (PIV) and three-dimensional velocity measurements by Doppler Velocimetry Acoustics (ADV) have shown that the flow kinematic quantities within the existing fishways are very important next to the small fish species capacities. One of strategies to answer at this problem is to introduce obstacles with cylindrical shape in the fishways pools. The adjunction of cylinders is intended to reduce the kinematics quantities of the turbulent flow within the fishways in order to adapt this hydraulic structure to the passage of small fish species. This strategy requires an optimization method to find the ideal location of the cylinders from numerical simulations of the flow (Star-CD code).

This thesis deals with the issue of extra performences, ie. constructional procurement contracts amendments. The main objektive was to compare the legislativ of extra performances in the Czech Republic and Germany and to study the influence of both legislations on the practice in the construction industry. There have been solved causes why the extra performances are needed and their legitimacy, as well as the consequences which are result from the imperfection of the legislative in both countries. There are also analyzed the cancelled perfomances and the question of edgibility against the extra performances. Finally there are sumarized some recommendations for both countries to improve their legal basis in this area.