Resultados em avaliações nacionais como Prova Brasil e Saeb dão indícios de que o ensino/aprendizagem de Matemática na Escola Básica tem sido deficiente. Na tentativa de entender como o aluno aprende para que o ensino ocorra de forma adequada a esse modo de construir o conhecimento, vários estudos têm sido realizados a respeito da Epistemologia do conhecimento. A Epistemologia de Gaston Bachelard afirma que a construção do conhecimento se dá com um movimento de ruptura frente ao conhecimento previamente estabelecido, com uma resistência à racionalização desse conhecimento denominado obstáculo epistemológico. O didata francês Brousseau traz a idéia de obstáculo epistemológico em Matemática como um obstáculo ligado à resistência de um saber mal adaptado e o vê como um meio de interpretar determinados dos erros recorrentes e não aleatórios cometidos pelos estudantes quando lhes são ensinados alguns conceitos matemáticos. A presente pesquisa teve por objetivo identificar obstáculos epistemológicos no ensino/aprendizagem de números reais por meio de questionários aplicados a alunos de 4ª série (ou 5º ano) a 8ª série (ou 9º ano) do Ensino Fundamental. / Results in national evaluations as Prova Brasil and Saeb give indications of that education/learning of Mathematics in the Basic School has been deficient. In the attempt to understand how the students learn so that education occurs of adequate form to this way to construct the knowledge, some studies have been carried through regarding the knowledges Epistemology. The Gaston Bachelards Epistemology affirms that the construction of the knowledge occurs through a movement of rupture front to the knowledge previously established, with a resistance to the rationalization of this knowledge called epistemological obstacle. The French didata Brousseau brings the idea of epistemological obstacle to Mathematics as an obstacle to the resistance of one to a badly suitable knowledge and sees it as a way to interpret some of the recurrent and not random errors committed by the students when some mathematical concepts are taught to them. The present research had for objective to identify to epistemological obstacles in education/learning of real numbers by means of applied questionnaires the students of 4th to 8th grade.

Resultados em avaliações nacionais como Prova Brasil e Saeb dão indícios de que o ensino/aprendizagem de Matemática na Escola Básica tem sido deficiente. Na tentativa de entender como o aluno aprende para que o ensino ocorra de forma adequada a esse modo de construir o conhecimento, vários estudos têm sido realizados a respeito da Epistemologia do conhecimento. A Epistemologia de Gaston Bachelard afirma que a construção do conhecimento se dá com um movimento de ruptura frente ao conhecimento previamente estabelecido, com uma resistência à racionalização desse conhecimento denominado obstáculo epistemológico. O didata francês Brousseau traz a idéia de obstáculo epistemológico em Matemática como um obstáculo ligado à resistência de um saber mal adaptado e o vê como um meio de interpretar determinados dos erros recorrentes e não aleatórios cometidos pelos estudantes quando lhes são ensinados alguns conceitos matemáticos. A presente pesquisa teve por objetivo identificar obstáculos epistemológicos no ensino/aprendizagem de números reais por meio de questionários aplicados a alunos de 4ª série (ou 5º ano) a 8ª série (ou 9º ano) do Ensino Fundamental. / Results in national evaluations as Prova Brasil and Saeb give indications of that education/learning of Mathematics in the Basic School has been deficient. In the attempt to understand how the students learn so that education occurs of adequate form to this way to construct the knowledge, some studies have been carried through regarding the knowledges Epistemology. The Gaston Bachelards Epistemology affirms that the construction of the knowledge occurs through a movement of rupture front to the knowledge previously established, with a resistance to the rationalization of this knowledge called epistemological obstacle. The French didata Brousseau brings the idea of epistemological obstacle to Mathematics as an obstacle to the resistance of one to a badly suitable knowledge and sees it as a way to interpret some of the recurrent and not random errors committed by the students when some mathematical concepts are taught to them. The present research had for objective to identify to epistemological obstacles in education/learning of real numbers by means of applied questionnaires the students of 4th to 8th grade.

This study proposes a new method for obstacle detection and avoidance using low-level MPEG-7 visual descriptors. The method includes training a neural network with a subset of MPEG-7 visual descriptors extracted from outdoor scenes. The trained neural network is then used to estimate the obstacle presence in real outdoor videos and to perform obstacle avoidance. In our proposed method, obstacle avoidance solely depends on the estimated obstacle presence data. In this study, backpropagation algorithm on multi-layer perceptron neural network is utilized as a feature learning method. MPEG-7 visual descriptors are used to describe basic features of the given scene image and by further processing these features, input data for the neural network is obtained. The learning/training phase is carried out on specially constructed synthetic video sequence with known obstacles. Validation and tests of the algorithms are performed on actual outdoor videos. Tests on indoor videos are also performed to evaluate the performance of the proposed algorithms in indoor scenes. Throughout the study, OdBot 2 robot platform, which has been developed by the author, is used as reference platform. For final testing of the obstacle detection and avoidance algorithms, simulation environment is used. From the simulation results and tests performed on video sequences, it can be concluded that the proposed obstacle detection and avoidance methods are robust against visual changes in the environment that are common to most of the outdoor videos. Findings concerning the used methods are presented and discussed as an outcome of this study.

En quoi le phénomène de hiatus, observé au sein des interactions langagières orales, peut-il devenir un révélateur d’obstacles aux apprentissages scolaires, dans les disciplines où l’émotion esthétique est sollicitée ?Pour traiter cette question, et plus spécifiquement le phénomène de hiatus et ses manifestations en situation scolaire, notre recherche convoque des travaux issus des sciences du langage, de la didactique, de la littérature, de la sociologie de l’éducation ainsi que de l’anthropologie. Prenant appui sur 7 corpus enregistrés dans des classes de fin de cycle 3, nous avons analysé le rôle et les marqueurs de hiatus dans la construction de contenus disciplinaires tels que la compréhension et l’interprétation d’œuvres littéraires ou de productions plastiques réalisées par les élèves. En tant qu’action langagière, le hiatus apparaît, dans les données recueillies, comme un lieu de tensions entre des sens et des significations, entre des pratiques sociales de référence déjà construites par certains élèves et des pratiques scolaires qui les convoquent, le tout au sein d’activités langagières scolaires et scolarisées. Selon nous, l’enjeu didactique est alors de faire de ces lieux de tensions, voire de ruptures, cognitivo-verbales - observables dans les discours - des « objets problèmes didactiques » afin notamment que les élèves en difficulté, et pourtant porteurs de questions en adéquation avec l’activité demandée par l’enseignant, puissent mener à bien la construction des objets enseignés. Au final, cette étude de cas permet de cibler des manifestations de hiatus en situation scolaire et d’interroger leurs effets sur la transformation des situations étudiées, sur la place et le rôle des apprenants, sur leurs difficultés scolaires dans les disciplines et les activités considérées ainsi que sur la construction de significations. / How may the phenomenon of hiatus, observed within oral language interactions, become an indicator of obstacles to school learning in school subject that appeal to aesthetic emotion?To address this question, and more specifically the phenomenon of hiatus and its outward signs in a school context, our research brings together work from language science, didactics, literature, educational sociology and anthropology. Focusing on 7 groups recorded at the end of the elementary school cycle, we have analysed the role and the markers of hiatus in the building of subject content such as the understanding and interpretation of literary works or the handiwork produced by pupils. As a language action, the phenomenon of hiatus appears in the data collected as a site of tension between senses and meanings, between benchmark social practices already acquired by certain pupils and school practices that summon them, all within school and school-related language activities. In our opinion, the didactic issue here is to turn these sites of cognitive-verbal tension or even rupture – observable in speech – into « didactic issue items » so that pupils experiencing difficulties – yet still asking questions that are relevant to the activity requested by the teacher – may succeed in their construction of the subjects being taught. Ultimately, this case study allows us to target outward signs of hiatus in a school context and to query their effects on the transformation of studied situations, on the place and role of teachers, on their schooling difficulties in the school subject and activities under consideration, and on the building of significations.

No description available.

La rencontre entre une couche limite laminaire se développant sur une plaque plane sous une surface libre et un obstacle rectangulaire émergent mène à l’apparition d’une zone de recirculation complexe appelée tourbillon en fer à cheval à l’amont de l’obstacle. Cette zone de recirculation est composée d’un certain nombre de vortex s’enroulant autour de l’obstacle et pouvant présenter des dynamiques variées. Le but de ce travail est de réaliser une étude expérimentale paramétrique du tourbillon en fer à cheval laminaire et faiblement turbulent. Les mesures sont réalisées par PIV et par trajectographies et des méthodes de détection basés sur la décomposition modale (POD) et la détection des points critiques sont utilisées afin de faciliter l’étude de la dynamique tourbillonnaire. Ce manuscrit se propose de : (i) Déterminer l’évolution des caractéristiques du tourbillon en fer à cheval en fonction des paramètres adimensionnels de l’écoulement. (ii) Mettre en place une typologie des différentes dynamiques exhibées. (iii) Déterminer les mécanismes à l’origine de l’apparition de ces différentes dynamiques à l’aide d’un modèle conceptuel. (iv) Et finalement, étudier l’influence de la longueur de l’obstacle sur le tourbillon en fer à cheval. / A laminar boundary layer developing under a free-surface and interacting with an emerging obstacle lead to the creation of a complex recirculation zone called horseshoe vortex upstream from the obstacle. This recirculation zone is composed of a given number of vortices wrapping around the obstacle with various kind of dynamics. The aim of this work is to perform an experimental parametric study of the laminar, and slightly turbulent horseshoe vortex. Measurements are obtained by PIV and trajectographies and detection method based on modal decomposition (POD) and critical points are used to ease the study of the vortex dynamics. This manuscript intends to : (i) Explain the horseshoe vortex main characteristics evolution with the non-dimensional parameters of the flow. (ii) Define a typology of the different observed vortex dynamics. (iii) Identify the physical mechanisms at the origin of those dynamics through the use of a conceptual model. (iv) And finally, show the influence of the obstacle length on the horseshoe vortex.

Cette thèse explore les ressources cognitives que mobilisent des élèves ingénieurs dans un APP (Apprentissage par problème) dans une tâche de conception d’un objet technique. La situation-problème à laquelle ces élèves sont confrontés est constituée par un système technique inédit de réfrigération sans apport extérieur d’énergie. Dans cet apprentissage, les élèves doivent concevoir l’objet technique et apprendre des concepts en thermodynamique. Deux groupes d’élèves sont comparés : le premier dispose d’un modèle analogique d’une situation connue pour aborder la situation nouvelle, le second ne dispose que du texte. Les questions de recherches : Que construisent ces élèves comme connaissances ?Qu’apportent ces deux types d’apprentissage (l’apprentissage par une situation connue et l’apprentissage par le texte) ? Quels sont les obstacles que rencontrent ces élèves ? Les hypothèses : un apprentissage par une situation connue conduit à la construction de connaissances opératives (des concepts outils). Un apprentissage par le texte conduit à la construction de connaissances décontextualisées (des concepts objets). Un apprentissage par les situations dans un dispositif didactique conduit ultérieurement à la construction de concepts catégoriels. Ces deux types d’apprentissage impliquent l’obstacle épistémologique dans la construction des concepts dans leurs deux fonctions : outil et objet. / This thesis investigates the cognitive resources that pupils engineers in a PBL (Problem based Learning) in a task of conception of a technical object mobilize. The situation-problem with which these pupils are confronted is constituted by an unpublished technical system of refrigeration without outside contribution of energy. In this learning, the pupils have to conceive the technical object and learn concepts in thermodynamics. Two groups of pupils are compared: the first one has an analogical model of a situation known to approach the new situation; the second has only the text. The questions of researches: what build these pupils as knowledge? What bring these two types of learning (the learning by a known situation and the learning by the text)? What are the obstacles which meet these pupils? The hypotheses: a learning by a known situation leads to the construction of operational knowledge (concepts tools). A learning by the text leads to the construction of knowledge out of context (concepts objects). A learning by the situations in a didactic device leads later to the construction of category-specific concepts. These two types of learning involve the epistemological obstacle in the construction of the concepts in them two functions: tool and object.

Si généralement, les variations de sections en travers des rivières naturelles ou anthropisées sont progressives et continues, au droit de certains biefs, des obstacles transversaux et discontinus (naturels ou artificiels) peuvent partiellement ou totalement bloquer les plaines d’inondation. L’écoulement dans la plaine d’inondation est dès lors contracté par l’obstacle, qui promeut le développement de zones de recirculation de part et d’autre de l’obstacle, entraînant une réduction de la section d’écoulement et la génération d’échanges de masse entre lits qui viennent se superposer aux interactions turbulentes. Nous nous sommes intéressés à la modélisation physique de ces écoulements et nous avons particulièrement étudié les distorsions introduites par l’obstacle sur la turbulence dans l’écoulement. Ce travail est basé sur de nouvelles expériences menées dans deux canaux à lit composé. Un jeu complet de données d’écoulements rapidement variés en présence d’un épi dans la plaine d’inondation. Les effets sur les paramètres hydrauliques de la superposition des deux problématiques que sont (i) les écoulements en géométries composées et (ii) les écoulements rapidement variés au voisinage d’un obstacle ont ensuite été analysés. Finalement, les processus physiques dominant dans ces écoulements ont été identifiés / If in natural or anthropized rivers, the river cross-section generally gradually and continuously varies, transversal and discontinuous obstacles either natural or artificial may partially or totally block off floodplains. The flow overbanking in the floodplain is therefore contracted by this obstacle which then promotes two recirculation zones of both sides of the obstacle, resulting in a reduction of the flow section and in the generation of strong mass exchange between channels that superimposes to the classical turbulent interactions. New experiments are conducted in two different compound channels: rapidly varied flows in compound channel with a groyne set on the floodplain. Flows with various groyne lengths and total discharges were investigated. Effects on the hydraulic parameters of the superimposition of the two problems that are (i) flow in compound geometry and (ii) rapidly varied flow in the vicinity of a thin obstacle were analysed. Finally, dominance of physical processes in such flow configuration is discussed

Le but de cette thèse est d'étudier la modélisation détaillée des écoulements qui ont lieu lors des inondations urbaines. Dans une première partie, des écoulements en bifurcation incluant des petits obstacles génériques ou des profils de canaux avec trottoirs sont étudiés sur une maquette expérimentale, puis simulés numériquement avec le modèle bidimensionnel Rubar20. Les résultats expérimentaux et numériques montrent l'avantage d'inclure des obstacles de petite taille dans un modèle d'inondation urbaine, alors qu'il n'y a qu'un intérêt limité à utiliser une topographie détaillée des rues. Dans une deuxième partie, les interactions entre écoulements de surface et écoulements en conduites souterraines sont étudiées. Un modèle physique de système de drainage urbain permet de valider un modèle analytique prédisant les débits d'échange entre les deux couches d'écoulement. Une modélisation 1D/2D (conduite/rue) est mise en place avec les modèles Rubar3/Rubar20 et validée sur des écoulements expérimentaux observés sur le modèle physique. Dans une troisième partie, les inondations dans la ville d'Oullins (près de Lyon, France) sont étudiées. La modélisation des écoulements de surface est validée avec des données de terrain, et nous discutons l'intérêt de plusieurs représentations du milieu urbain. L'intégration du réseau d'assainissement dans un modèle 1D/2D reste affectée par plusieurs incertitudes, mais cette étape montre l'intérêt de la modélisation couplée pour décrire les interactions complexes des écoulements lors d'inondations urbaines, ainsi que les limites de l'approche développée pour les écoulements à faible profondeur / Aim of this thesis is to study the detailed modelling of flows that occur during urban floods. In a first part, bifurcation flows including small obstacles or channel profiles with sidewalks are studied on an experimental facility, and then numerically simulated with the two dimensional model Rubar20. Experimental and numerical results show the benefits of including small obstacles in an urban flood model, whereas there is only little benefit of using a detailed representation of the streets topography. In a second part, interactions between surface and underground pipe flows are studied. A physical model of an urban drainage system allows the validation of an analytical model predicting exchange discharges between both flow layers. A 1D/2D modelling (pipe/street) is set up with the models Rubar3/Rubar20 and validated on experimental flows observed on the physical model. In a third part, floods in the city of Oullins (near Lyon, France) are studied. Surface flows modelling is validated with field data, and we discuss the interest of several representations of the urban area. Integration of the sewer system in a 1D/2D model remains impacted by several uncertainties, yet this step shows the interest of the coupled modelling to describe complex flows interactions during urban floods, as well as limitations of the developed approach for shallow flows

Extreme obstacle racing is a brand new sporting industry that is currently developing most not only in Europe but also around the world. I focused mainly on introducing this new sport in order to find out different level of the motor skills of beginners and professionals. In the theoretical part of my work, I defined what is characteristic for this sport and why it is so famous and wanted today. In the practical part, using the proposed test battery, I tested all the motor skills of beginners and professionals in order to identify the real physical differences between them. As a result of these facts, methods of testing, observation, processing, evaluation, analysis and statistics of data, along with the study of professional literature, were used. Based on the established hypotheses, I asked questions that I had in my opinions and attitudes to the beginners and professionals of this thriving sport. Through research and testing, we have found that professionals are certainly more dominant in motor skills than beginners with overall predominance in all underlying motor tests that included speed, endurance, strength and coordination tests. The benefit of this work is the analysis and introduction of a new sporting industry, including the main discovery of real differences between beginners and...