This work takes place in the context of distribution power system protection and tries to improve the detection and location of earth faults. The protection problem is vast and many ideas emerge every year to enhance the reliability of the grid. The author has focused his energy into the compensated and isolated network protection in the specific case of single phase earth fault. This PhD thesis is divided in two main parts that might be considered as independent. The first part studies the detection of single phase earth fault and the second analyzes the fault location of such fault.<p><p>Pragmatism was asked during these three years because a product development was necessary especially regarding the fault detection problem. The first part of the thesis took 18 months of research and development to obtain a prototype of transient protection able to detect single phase earth fault in compensated and isolated network. The sensitivity of the algorithm has been emphasized regarding the fault impedance and to detect earth fault up to 5 kOhm depending on the network characteristic. The fault location problem has been much more theoretical although the problem links to the accuracy of the algorithm and its robustness regarding wrong fault location indication has been strongly considered.<p><p>Compensated networks and in some conditions isolated networks are distribution from 12 kV up to 110 kV mostly used in East and North Europe but also in China. Others areas also work with such networks but they also have others systems and they do not use them on all the territory. These networks have the particularity to obtain very small fault current in case of single phase earth fault. Low current means the difference between a faulty and a sound feeder is not significant. Therefore classic overcurrent protection is completely useless to protect the network, forcing the development of more complex algorithm. A possibility to overcome the problem of the small fault current is to develop a transient protection. The transient occurring at the beginning of the fault has strong information to distinguish a faulty from a sound feeder. In this work I have chosen to use not only the transient but also the steady state to get the best sensitivity.<p><p>Then the fault location has been investigated but the small information coming from the faulty feeder is not sufficient to have a precise enough position of the fault. Therefore, active system has been suggested to be implemented in the grid to increase the faulty current and have enough power for a precise location. Different existing algorithms based on the steady state at the nominal frequency are compared using a tool developed during this work. Recommendations are then made depending on the topology, the network parameters, the measurements precision, etc. Due to the complexities of the problem, a simulator has been coded in Matlab .The user of a possible fault location must then use this tool to understand and see the future fault location precision that he could obtain from different algorithm on his network. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

Policies to reduce emissions from transportation are implemented by different World and European<p>associations. Personal and freight transportation is one of the key contributors in GHG<p>emissions, being the second biggest GHG emitter after energy sector in the European Union.<p>The policies to reduce emissions from transportation are focusing on the optimization of the efficiency<p>of the existing vehicles, the development of new sustainable fuels and propulsion systems<p>and the electrification of the vehicles<p>The continuously increasing price of the permanent magnets and the shortage of rare earths<p>demand the finding of alternatives for the permanent magnet synchronous machines which is<p>currently the leading technology in several domains as hybrid and full electric propulsion and<p>wind turbines due to their best overall performances.<p>The good efficiency and the large constant power-speed ratio in addition to low the cost, high<p>reliability and fault-tolerance make the SRM a candidate with real chances on the market of<p>vehicle propulsion. The main drawbacks of the SRM related to the torque ripple, noise and<p>vibration make the research object in R&Ds all over the world.<p>This thesis is focused on the development of an efficient and robust switched reluctance drive<p>which can be integrated in a hybrid dive train or can be solely used for electric vehicle traction.<p>To achieve this goal, various instantaneous and average torque control techniques are implemented<p>and compared. A converter is designed, built and integrated on a test bench which<p>allows testing SRMs for vehicle propulsion. An investigation on noise production in SRDs ends<p>the thesis. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

Abstract<p><p>This thesis deals with the operation of and winding short-circuit fault detection in a Doubly-Fed Induction Generator (DFIG) based Wind Turbine Generator System (WTGS). Both the faulted and faultless condition of operation has been studied, where the focus is on the electrical part of the system. The modelled electrical system is first simulated and the developed control system is then validated on a test bench. The test-bench component dimensioning is also discussed.<p><p>The faultless condition deals with the start-up and power production mode of operation. Control design based on the Proportional Integral (PI) control technique has been compared for power and torque control strategies against the Linear Quadratic Gaussian (LQG) control technique, at different operating points through the variable-speed region of WTGS operation following the maximum power curve of the system. It was found that the torque control strategy offered less degradation in performance for both the control techniques at operating points different for the one for which the control system was tuned. The start-up procedure of the DFIG based WTGS has been clarified and simplified. The phase difference between the stator and the grid voltage, which occurs due to the arbitrary rotor position when the rotor current control is activated, is minimized by using a sample-and-hold technique which eliminates the requirement of designing an additional controller. This method has been validated both in simulation and experiments.<p><p>The faulted condition of operation deals with the turn-turn short-circuit fault in the phase winding of the generator. The model of the generator, implemented using the winding-function approach, allows the fault to be created online both in a stator and a rotor phase. It has been demonstrated that the magnitude of the current harmonics, used extensively in literature for the Machine Current Signature Analysis (MCSA) technique for winding short-circuit fault detection, is very different when the location of the fault is changed to another coil within the phase winding. This makes the decision on the threshold selection for alarm generation difficult. Furthermore, the control system attenuates the current harmonics by an order of magnitude. This attenuation property is also demonstrated through experiments. The attention is then shifted to the negative-sequence current component, resulting from the winding unbalance, as a possible fault residual. Its suitability is tested in the presence of noise for scenarios with different fault locations, fault severity in terms of the number of shorted-turns and grid voltage unbalance. It is found that due to the presence of a control system the magnitude of the negative-sequence current, resulting from the fault, remains almost the same for all fault locations and fault severity. Thus, it was deemed more suitable as a fault residual. In order to obtain a fast detection method, the Cumulative Sum (CUSUM) algorithm was used. The test function is compared against a threshold, determined on the basis of expected residual magnitude and the time selected for detection, to generate an alarm. The validation is carried out with noise characteristics different from the ones used during the design and it is shown that the voltage unbalance alone is not able to trigger a false alarm. In all the scenarios considered, the detection was achieved within 40 ms despite the presence of measurement filters. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

Cette thèse en histoire de la philosophie propose une reconstruction interprétative de la cohérence synchronique et diachronique de la philosophie de Johann Gottlieb Fichte à la lumière de la dynamique perspectiviste de sa pensée transcendantale. Notre recherche part du problème systématique de la philosophie appliquée, c’est-à-dire du passage du point de vue transcendantal à son application dans l’action empirique. En effet, un tel passage est, d’une part, exigé comme une tâche essentielle adressée à la philosophie fichtéenne conformément à son unité théorico–pratique mais, d’autre part, il est rendu problématique par la différenciation principielle entre le point de vue de la réflexion transcendantale et le point de vue de la conscience empirique du donné factuel. <p>Il s’agit d’abord d’élucider les prémisses spéculatives de ce problème dans une théorie des points de vue inscrite au cœur des exposés de la Doctrine de la science (Wissenschaftslehre, WL). Nous tentons ainsi de réinterpréter les différentes versions de la WL qui vont de 1794 à 1804 en nous concentrant sur tous les concepts et procédures épistémologiques qui ressortissent à une logique perspectiviste, pour les appréhender comme des opérateurs de réflexivité du savoir philosophique dans l’auto–construction de la WL. C’est dans une telle dynamique perspectiviste que la tension conceptuelle constitutive du problème de la philosophie appliquée entre le point de vue transcendantal et le point de vue empirique ou entre le système et la vie prend tout son sens philosophique.<p>Cette dynamique perspectiviste qui opère au fondement spéculatif de la WL se prolonge et se concrétise ensuite dans une phénoménologie des visions du monde (Weltansichten) pensées comme points de vue de la liberté, qui trouve sa forme la plus aboutie en 1806. Le point de vue transcendantal de la liberté reconnaît alors sa genèse dans quatre points de vue empiriques qui attachent la liberté respectivement à la nature, à la loi, à l’action créatrice ou à la vie divine. C’est cette phénoménologie que nous mobilisons enfin pour mettre à l’épreuve son potentiel heuristique comme une logique de l’action ou une praxéologie de la liberté dans les écrits de philosophie appliquée et principalement dans le domaine de la philosophie politique. <p>Bref, la philosophie transcendantale de Fichte se développe selon une dynamique perspectiviste qui génère, d’une part, le fondement spéculatif du problème systématique de l’application empirico–pratique de la philosophie transcendantale, et qui livre, d’autre part, en tant que théorie transcendantale des points de vue pratiques, les ressources phénoménologiques et praxéologiques pour une heuristique de la liberté dans la philosophie appliquée.<p>Dans une deuxième partie plus exploratoire, nous cherchons à tester à la fois la signification moderne et le potentiel actuel du lien conceptuel entre réflexivité, perspectivité et liberté mis en exergue dans le système fichtéen. Nous construisons d’abord une série de dialogues que Fichte a pu ou aurait pu mener avec d’autres philosophes de l’époque moderne, en ciblant particulièrement l’idée perspectiviste comme fil conducteur des confrontations avec ces différents systèmes (Leibniz, Kant, Schelling et Hegel). Nous tentons pour finir une incursion dans le champ de la philosophie contemporaine en vue de mettre au jour une postérité cachée de la philosophie fichtéenne dans la pragmatique transcendantale de Karl–Otto Apel à travers une homologie structurelle entre ces deux philosophies, s’attestant notamment dans les questions de la fondation transcendantale du point de vue moral, de son application politique et des rapports qu’il doit entretenir avec d’autres points de vue inscrits dans la dialectique perspectiviste des intérêts de connaissance.<p> / Doctorat en Philosophie / info:eu-repo/semantics/nonPublished

Let’s imagine a typical word-learning scenario. A toddler sits in her highchair in the kitchen and waits for her lunch. Her mother says: “Use a spoon to eat your meal”. Several objects are placed in front of the child. She can see a dish with her lunch, a spoon, a cup, a sugar bowl, a milk jar, her mother’s plate and a second cup. All these objects, present in the visual array, must be identified by the toddler; she must also parse the auditory stream into segments and determine which words are familiar and which ones are potentially new. If the child does not know the word “spoon”, she will need to use the event of naming of this referent by her mother to adjust her attention to the relevant referent. She also needs to update her representation of this word upon hearing it in different contexts with different speakers and, perhaps, different types of spoons. Efficient attention allocation in this word-learning situation will clearly contribute to the success of mapping; the degree of encoding of the word-form and of its meaning will certainly influence whether this word enters the child’s vocabulary.The complexity of such a typical scenario seems very challenging for a toddler whose cognitive resources are still far from being fully mature. Unsurprisingly, several accounts of how toddlers manage to solve this task are currently on the market. The problem of ambiguity associated with meaning-to-referent mapping (several objects co-presented in the visual scene) and with word form-to-meaning mapping (the correct word is to be singled out among phonological competitors) might be even more challenging for children who present an atypical developmental trajectory.Children with Autism Spectrum Disorder and toddlers at risk for the disorder were found to acquire their vocabularies at a slower rate than their typically developing peers. In the contemporary literature, this delay in lexical knowledge acquisition is associated with poor socio-pragmatic understanding that presumably limits children’s capacity to establish referents for words in social contexts. Since impaired understanding of social interaction is a core characteristic of the cognitive profile of individuals with ASD, such an explanation of the delay in language development seems very plausible. However, several other theoretical accounts hold that in typical development socio-pragmatic skills emerge, bottom-up, through more domain-general processing of interactional experiences. In line with the latter views, it can be hypothesized that delays in lexical acquisition in ASD are not directly linked to poor socio-pragmatic understanding but are caused by low-level deficits and atypical attention allocation during word learning.Research programs on lexical learning and processing in ASD thus face the existence of different, contradictory theories of first language acquisition in typical development. Deciding a priori to build one’s experimental study against this or that theoretical background carries the risk of a limited interpretation of experimental results. A more promising way to deal with the variety of available theories of language acquisition is rather to directly confront the existing paradigms and to plan the study design in accordance. This is the approach that I privilege here. In the studies presented within this thesis, I question how social cues are used to resolve ambiguity in meaning during word-learning tasks (chapter 1) and during referential processing in typically developing children (chapter 2) and in children with ASD (chapter 3). Not only do I attempt to compare the use of social cues in word-learning and of perspectival information in referential processing in children with and without ASD, but I also try to link these results with two opposing theoretical views: the one that postulates early reliance on socio-pragmatic understanding and the other that conceives of word-learning as not being necessarily grounded in social understanding. In Chapter 1, I present evidence that children with ASD, children with SLI and typically developing children learn novel words in a flexible way by selectively attending to mappings offered by previously accurate speakers. However, I also show that such learning is likely to be supported by a surface trait attribution mechanism, rather than by genuine socio-pragmatic understanding: children in both clinical groups fail to learn selectively, when learning requires genuinely building a model of the speakers’ epistemic states. Chapters 2 and 3 are devoted to referential communication. I adopt several analytical and methodological modifications to existing methods, which allows me to compare two different aspects of partner-dependent processing of referential precedents. Typically developing children can be expected to recognize precedents previously established with the same partner faster, because of an automatic priming mechanism. However, potential faster processing of broken precedents with a new partner could not be explained by a low-level memory mechanism and would strongly suggest that lexical processing is influenced by expectations about the child’s partner perspective. I present evidence that children with and without ASD do not spontaneously rely on common ground during referential processing and that partner-specific effects in processing are associated with low-level priming. In chapter 3, I report evidence of impaired ability to switch between different conceptual perspectives in children with ASD, which may lead to maladaptive behavior in communication. In the last chapter of this thesis, I explore how word form-to-meaning ambiguity is resolved in children with ASD and whether these children exhibit difficulty in correctly mapping similar-sounding novel words. The results of this study suggest that lexical activation in children with ASD may be impaired and they display deficits in suppressing phonological competitors. Taken together, the results presented in this doctoral dissertation suggest that delays in word acquisition in ASD are likely to be driven by deficits in domain-general cognitive development. Even though impaired socio-cognitive understanding may lead to difficulties in discourse and pragmatics in older children, delayed access to lexical meaning in young children with ASD is likely to be associated with disruptions in domain-general mechanisms of perception, attention and memory. / Doctorat en Langues, lettres et traductologie / info:eu-repo/semantics/nonPublished

Today, development of accurate early diagnosis of cancers thus became the number one challenge of medicine during the 21st century as the current techniques relies on imaging methods that suffer from low sensitivity and misdiagnosis.For these reasons, in this work, we aimed at developing a no-wash colorimetric biosensor for the detection of the oncoprotein Mdm2. Indeed, abnormal levels of Mdm2 could be related to the early formation of tumors.This thesis is devoted to the conception of a no-wash colorimetric biosensor for the detection of the oncoprotein Mdm2. This work can be divided in four parts:(i) The detection strategy and the design of the recognition elements (Chapter I).(ii) The conjugation of gold nanoparticles with the recognition elements (Chapter II, III, IV, V and VI).(iii) The modification of the metallic core of the nanoparticles (Chapter VII).(iv) The use of the optimized biosensor for the detection of Mdm2 (Chapter VIII).In the first part, we investigated the sensing strategy. An aggregation-based assay with plasmonic nanoparticles was selected, as the detection signal is a change of color of the suspension that can be observed to the naked eye or by UV-Vis spectroscopy. We designed the recognition elements, two peptide aptamers coming from endogenous proteins p53 and p14, and we grafted them separately on two batches of gold nanoparticles (AuNPs) via thiol end-groups. We used these latter for the detection of various concentrations of Mdm2 in buffer using our dual-trapping strategy with these two batches of functionalized AuNPs. We demonstrated that both peptides are able to interact with Mdm2 even after grafting onto the particles and that this detection strategy is highly specific. However, this first sensor presented some drawbacks, such as a poor colloidal stability of the AuNPs and a limited dynamic range.With the aim to encompass these issues we investigated, in the second part of this thesis, alternative strategies to conjugate the peptides to the particles. We investigated the functionalization of the particles with stabilizing ligands such as thiolated poly(ethyleneglycol) (HS-PEG). We first studied their simultaneous grafting with the peptides on the AuNPs. We observed that grafting HS-PEGs and peptides side-by-side allowed to control the density of peptides conjugated to the AuNPS and increased drastically the stability of the particles. However, the detection of Mdm2 was strongly hindered by the presence of PEG on the particles carrying the p14 peptide. In a second step, we investigated the conjugation of peptides on the top of a PEG layer carrying functional groups (HS-PEG-X where X is a carboxylate or an alkyne). AuNPs were first functionalized with mixtures of HS-PEG and HS-PEG-X, and the peptides were conjugated to the functional groups via amide bond formation or CuAAC coupling in a second step. However, we noticed that it was not possible to control the composition of the mixed layer of PEGs and thus the peptide grafting density.Due to the lack of recognized protocols in the literature for (i) the determination of the chemical and colloidal stabilities of AuNPs and (ii) the determination of the proportion of different ligands in the organic coating of the particles, we developed two interesting tools. The first one was a convenient method allowing to evaluate by UV-Vis spectroscopy the efficiency of the citrate exchange process using thiol-, alkyne- or diazonium-ligands from gold nanoparticles synthesized via a Turkevich method. The second protocol was a method allowing to quantify the proportion of two HS-PEGs ligands grafted in mixtures onto gold nanoparticles via 1H NMR spectroscopy.As we couldn’t find conditions in which the proportion of multiple thiolated ligands can be controlled on AuNPs, we decided to investigate another functionalization strategy based on the use of calix4arene-diazonium salts.We first studied the grafting on AuNPs of calixarenes bearing four PEG chains at the level of their small rim, one ended by a carboxylic acid and three by a methoxy group. The calixarene layer allowed to obtain AuNPs covered by a very dense PEG shell (with more PEG chains/nm2 that what was obtained previously with thiol anchoring). In addition to that, this PEG shell was strongly anchored to the AuNPs, conferring them a very high colloidal and chemical robustness. We then combined the grafting of this calixarene with the grafting of another non-functional calixarene, bearing four PEG chains ended by a methoxy group, and we quantified the conjugation capacity of such particles by amide bond formation. We demonstrated that this strategy allows to (i) increase drastically the stability of the AuNPs and (ii) control the proportion of peptide conjugated at their surface. Finally, we showed that calixarene-coated AuNPs to which to the p53 and p14 peptides have been conjugated could be used to detect Mdm2.With the evidence that the peptide conjugation density could be controlled using calixarene-coated AuNPs, we investigated the simultaneous grafting of two functional calixarenes on particles: one bearing four carboxylic acids groups and one bearing four PEG chains ended by alkyne groups. We optimized the grafting of these calixarenes in mixed layers on the AuNPs as well as their conjugation. We demonstrated that the grafting of two functional calixarenes led to the production of bi-functional AuNPs, capable of conjugation with two molecules via two distinct chemistries.In the third part, we optimized the composition of the metallic core of the biosensor. As it is well known that silver nanoparticles express better optical properties than gold nanoparticles of the same size, we aimed to incorporate silver nanoparticles (AgNPs) in the biosensor. This was a true challenge due to the intrinsic low chemical stability of silver nanoparticles that greatly limits their use in IVD. For this purpose, we developed an innovative in situ synthesis of silver nanoparticles in the presence of the calixarene-diazonium salts. After optimization of the synthesis, we observed that calixarenes bearing four carboxylic acids groups at the level of their small rim allowed the production of ultra-stable silver nanoparticles to which biomolecules can easily be conjugated. This in situ synthesis procedure even allowed us to produce alloy nanoparticles, with metallic cores whose composition could easily be tuned from pure silver to silver/gold alloys or pure gold. With this synthesis, the composition of the organic layer could also be easily tuned by using mixtures of calixarenes-diazonium salts.Finally, in the last part, we investigated the detection of Mdm2 with the optimized version of the biosensor, i.e. silver nanoparticles coated by a calixarene layer to which the p53 and p14 peptides were conjugated. With this novel class of nanoparticles, we could encompass the two initial drawbacks of the initial sensor. First, we were able to detect Mdm2 with a wider detection range and a lower limit. Secondly, the particles were sufficiently stable and robust to be dispersed in physiological fluids and we could detect Mdm2 in human serum without interference. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

Orientador: Rosa Maria Manzoni / Resumo: Trata-se de uma pesquisa de intervenção pedagógica que objetiva identificar as possíveis transferências e adaptações operadas nas capacidades de linguagem e na mobilização de conceitos ao se produzirem gêneros de agrupamentos distintos (um diário e um abaixo-assinado). Fundamentam teoricamente a pesquisa tanto a Psicologia Histórico-Cultural, por meio das contribuições sobre aprendizagem e desenvolvimento, com a noção de zona de desenvolvimento proximal, e sobre o processo de formação de conceitos espontâneos e científicos (VIGOTSKI, 1991, 2009) quanto o Interacionismo Sociodiscursivo, no qual amparamos a noção de gênero como instrumento promotor de aprendizagem e desenvolvimento (SCHNEUWLY, 1994, 2004) e de onde extraímos as categorias de análise textual (BRONCKART, 2009) que permitem observar as capacidades de linguagem dos aprendizes (DOLZ, PASQUIER, BRONCKART, 1993). A produção dos dados da pesquisa foi metodologicamente orientada pela Engenharia didática, por meio do procedimento das Sequências didáticas (DOLZ, NOVERRAZ e SCHNEUWLY, 2004) e da modelização didática dos gêneros (DE PIETRO e SCHNEUWLY, 2003; SCHNEUWLY e DOLZ, 2004). Na preparação da pesquisa, foram feitas adaptações nas práticas sociais de referência dos gêneros diário íntimo e pessoal e abaixo-assinado a fim de torná-los objetos de ensino; posteriormente estes gêneros foram inseridos em uma sequência didática desenvolvida com estudantes concluintes do ensino médio prevendo a produção de um diário, no iníci... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: It is a research of pedagogical intervention that aims to identify the possible transfers and adaptations operated in the language abilities and in the mobilization of concepts when producing genres of different groups (a diary and a petition). Theoretical research is based on both Historical-Cultural Psychology, through contributions on learning and development, with the notion of a zone of proximal development, and on the process of forming spontaneous and scientific concepts (VIGOTSKI, 1991, 2009) and Interactionism Sociodiscursive, in which we support the notion of gender as an instrument that promotes learning and development (SCHNEUWLY, 1994, 2004) and from which we extract the categories of textual analysis (BRONCKART, 2009) that allow observing the language skills of learners (DOLZ, PASQUIER , BRONCKART, 1993). The production of the research data was methodologically oriented by Didactic Engineering, through the Didactic Sequences procedure (DOLZ, NOVERRAZ and SCHNEUWLY, 2004) and the didactic modeling of the genres (DE PIETRO and SCHNEUWLY, 2003; SCHNEUWLY and DOLZ, 2004). Na preparation of the research, adaptations were made to the social practices of reference of the intimate and personal daily and petitioned genres in order to make them objects of teaching; later these genres were inserted in a didactic sequence developed with high school students predicting the production of a diary, at the beginning, and that of a petition, at the end. The confrontation between ... (Complete abstract click electronic access below) / Résumé: C'est une recherche d'intervention pédagogique qui vise à identifier les possibles transferts et adaptations opérés dans les capacités langagières et dans la mobilisation des concepts lors de la production de genres de différents groupes (journal intime et pétition). La recherche théorique est basée à la fois sur la psychologie historique et culturelle, à travers des contributions sur l'apprentissage et le développement, avec la notion de zone de développement proximal, et sur le processus de formation de concepts spontanés et scientifiques (VIGOTSKI, 1991, 2009) et l'interactionnisme Sociodiscursive, dans laquelle nous soutenons la notion de genre comme instrument favorisant l'apprentissage et le développement (SCHNEUWLY, 1994, 2004) et dont nous extrayons les catégories d'analyses textuelles (BRONCKART, 2009) qui permettent d'observer les compétences linguistiques des apprenants (DOLZ, PASQUIER, BRONCKART, 1993). La production des données de recherche a été orientée méthodologiquement par l'ingénierie didactique, à travers la procédure des séquences didactiques (DOLZ, NOVERRAZ et SCHNEUWLY, 2004) et la modélisation didactique des genres (DE PIETRO et SCHNEUWLY, 2003; SCHNEUWLY et DOLZ, 2004). Na préparation de la recherche, des adaptations ont été apportées aux pratiques sociales de référence des genres intimes et personnels quotidiens et pétitionnés afin d'en faire des objets d'enseignement; plus tard ces genres ont été insérés dans une séquence didactique développée avec ... (Résumé complet accès életronique ci-dessous) / Mestre

In this work, a Representative Volume Element (RVE) generator based on the distance fields of arbitrary shaped inclusion packing is used to obtain morphologies of open-foam materials. When the inclusions are spherical, the tessellations of the resultant packing creates morphologies that are similar to physical foam samples in terms of their face-to-pore ratio, edge-to-face ratio and strut length distribution among others. Functions that combine the distance fields can be used to obtain the tessellations along with the necessary variations in the strut geometry and extract these open-foam morphologies. It is also possible to replace the inclusion packing with a predefined set of inclusions that are directly extracted from CT-scan based images.The use of discrete level-set functions results in steep discontinuities in the distance function derivatives. A multiple level-set based approach is presented that can appropriately capture the sharp edges of the open-foam struts from the resultant distance fields. Such an approach can circumvent the discontinuities presented by the distance fields which might lead to spurious stress concentrations in a material behavior analysis.The individual cells are then extracted as inclusion surfaces based on said combinations of the distance functions and their modifications. These surfaces can be joined together to obtain the final geometry of the open-foam morphologies. The physical attributes of the extracted geometries are compared to the experimental data. A statistical comparison is presented outlining the various features. The study is extended to morphologies that have been extracted using CT-scan images. With the help of mesh optimization tools, surface triangulations can be obtained, merged and developed as finite element (FE) models. The models are ready to use in a multi-scale study to obtain the homogenized material behavior. The upscaling can help assess the practical applications of these models by comparing with experimental data of physical samples. The material behavior of the RVEs are also compared with the experimental observations. To increase the computational efficiency of the study, a neural network based surrogate is presented that can replace the micro-scale boundary value problem (BVP) in the multi-scale analysis. The neural networks are built with the help of modules that are specifically designed to predict history dependent behavior and are called Recurrent Neural Networks (RNN). The surrogates are trained to take into account the randomness of the loading that complex material undergo during any given material behavior analysis. / Dans ce travail, un générateur de volumes élémentaires représentatifs (VER) basé sur les champs de distance d'un agrégat d'inclusions de forme arbitraire est développé dans le cadre de matériaux moussés à structure ouverte. Lorsque les inclusions sont sphériques, la tessellation de l'agrégat résulte en des morphologies similaires aux échantillons de mousse physique en termes de rapports des nombres de face par pores et de bords par faces, ainsi que de la distribution de la longueur des entretoises, entre autres. Les fonctions qui combinent les champs de distance peuvent être utilisées pour obtenir des tesselations avec les variations nécessaires aux géométries des entretoises et extraire ces morphologies de mousse ouverte. Il est également possible de remplacer l'agrégat d'inclusions par un ensemble prédéfini d'inclusions qui sont directement extraites d'images tomographiques.L'utilisation de fonctions de niveaux discrètes entraîne de fortes discontinuités dans les dérivées des champs de distance. Une approche basée sur des ensembles de niveaux multiples est présentée qui peut capturer de manière appropriée les arêtes vives des entretoises des mousses ouvertes à partir des champs de distance résultants. Une telle approche peut contourner les discontinuités présentées par les champs de distance qui pourraient conduire à des concentrations de contraintes parasites dans une analyse ducomportement des matériaux.Les pores individuels sont ensuite extraits en tant que surfaces d'inclusions sur la base desdites combinaisons des fonctions de distance et de leurs modifications. Ces surfaces peuvent être réunies pour obtenir la géométrie finale des morphologies de mousse ouverte. Les attributs physiques des géométries extraites sont comparés aux données expérimentales. Une comparaison statistique est présentée décrivant les différentes caractéristiques. L'étude est étendue aux morphologies qui ont été extraites à l'aide d'images tomographiques.À l'aide d'outils d'optimisation de maillage, les triangulations des surfaces peuvent être obtenues, fusionnées et développées sous forme de modèles d'éléments finis (FE). Les modèles sont prêts à être utilisés dans une étude multi-échelle pour obtenir le comportement homogénéisé du matériau. La mise à l'échelle peut aider à évaluer les applications pratiques de ces modèles en les comparant aux données expérimentales d'échantillons physiques. Le comportement des matériaux des VERs est également comparé aux observations expérimentales.Pour augmenter l'efficacité de calcul de l'étude, un modèle de substitution basé sur un réseau neuronal est présenté. Ce modèle peut remplacer le problème aux valeurs limites à l'échelle micro dans une analyse multi-échelle. Les réseaux de neurones sont construits à l'aide de modules spécialement conçus pour prédire le comportement dépendant de l'histoire et sont appelés réseaux de neurones récurrents (RNN). Les modèles de substitution sont entrainés pour prendre en compte le caractère aléatoire du chargement que subit un matériau complexe lors d'une analyse de comportement d'un matériau. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

Les systèmes embarqués sont de plus en plus présents dans notre quotidien, à l’instar des téléphones ou des équipements des voitures modernes. Les systèmes embarqués modernes utilisent des plates-formes de plus en plus complexes. Après avoir longtemps utilisé un seul processeur, les plates-formes modernes peuvent désormais contenir plusieurs processeurs. Depuis quelques années, afin de continuer à améliorer la performance de ces systèmes à moindre coût, certaines de ces plates-formes embarquent désormais plusieurs processeurs différents, parfois même capables de modifier rapidement leurs caractéristiques pendant l’exécution du système. C’est ce qu’on appelle des plates-formes hétérogènes.Cette thèse traite de l’ordonnancement d’applications temps réel strict pour des plates-formes hétérogènes reconfigurables. Établir une polituqe d’ordonnancement consiste à garantir l’exécution d’ensembles de tâches récurrentes, avec le respect des contraintes temporelles de chaque tâche. Dans un contexte de temps réel strict, une tâche doit nécessairement être pleinement exécutée avant son échéance. Tout retard pourrait compromettre la sécurité du système ou des utilisateurs.Produire un ordonnancement temps réel strict efficace pour de telles plates-formes hétérogènes est particulièrement difficile. En effet, la vitesse d’exécution d’un processeur d’une telle plates-forme dépend à la fois du type du processeur et de la tâche exécutée. Cela rend les tâches difficilement interchangeables et augmente ainsi considérablement la complexité des polituqes d’ordonnancement. De plus, le coût d’une migration – le déplacement d’une tâche en cours d’exécution – d’un processeur à un autre est élevé, ce qui peut rendre les polituqes d’ordonnancement peu efficaces en pratique.Dans cette thèse, deux voies sont explorées pour tirer parti des possibilités offertes par ces plates-formes hétérogènes. Tout d’abord, en proposant un ordonnanceur dit global, qui permet une utilisation théorique de l’entièreté de la plates-forme. Pour atteindre cet objectif, nous isolons différents sous-problèmes, en suivant un schéma établi par la littérature existante. Pour chaque sous-problème, nous proposons une amélioration significative par rapport à l’état de l’art. L’ensemble constitue un nouvel ordonnanceur. Une évaluation empirique montre que ses performances sont bien supérieures à celles des ordonnanceurs existants. De plus, la polituqe d’ordonnancement proposée a une meilleure applicabilité, car elle réduit le nombre de migrations d’un processeur à un autre.Une deuxième voie explorée est le paradigme d’application dite multimode. Nous proposons ici le premier modèle où le matériel comme le logiciel peuvent être modifiés pendant l’exécution de l’application, afin de s’adapter au contexte dans lequel elle se trouve. Enfin, deux nouveaux protocoles utilisant ce modèle sont proposés et évalués. Il est montré théoriquement et empiriquement que ces protocoles présentent une faible complexité et de bonnes performances, et correspondent donc au besoin d’applications réelles. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Cette thèse contribue à rendre le marché de la rénovation énergétique durable et autonome. L’objectif est de contribuer à quantifier le risque de non atteinte de la performance énergétique après rénovation. Tout d’abord, nous analysons les facteurs psychologiques des ménages à prendre en compte pour améliorer les modèles de prédictions de consommation d’énergie. Via le programme Je rénove BBC, nous mettons en évidence quatre biais cognitifs impactant l’écart de la consommation d’énergie réelle et prédite. Puis, nous étudions les structures de contrats les plus appropriés pour améliorer le déroulement des chantiers, incitant les artisans à mieux travailler. D’une part, nous déterminons des contrats pour un Agent devant effectuer deux tâches et sous-estimant l’impact de l’une d’entre elles sur la performance du bâtiment. D’autre part, nous testons des incitations individuelles et collectives sur la capacité de plusieurs artisans à se coordonner selon leur formation initiale (DORéMI, …). / This thesis aims at contributing to make the energy renovation market long-lasting and self-sustaining. To achieve this, our objective is to quantify the risk of not achieving energy performance after renovation. First, we analyze households’ psychological factors that should be considered to improve energy consumption prediction models. Drawing on the Je rénove BBC program, we highlight four cognitive biases that negatively impact the difference between actual and predicted energy consumption. We then study the most appropriate contract structures improving the flow and quality of renovation projects, encouraging craftsmen to work better. On one hand, we determine optimal contracts for an Agent who has to perform two tasks and underestimates the impact of one of them on the building's performance. On the other hand, we test individual-based and group-based incentives on the ability of several real Agents (craftsmen) to coordinate, according to their initial training (DORéMI, …).