WorldCat Identities

École doctorale des sciences pour l'ingénieur (Clermont-Ferrand)

Overview
Works: 437 works in 442 publications in 2 languages and 444 library holdings
Roles: Other, Degree grantor
Publication Timeline
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Most widely held works by École doctorale des sciences pour l'ingénieur (Clermont-Ferrand)
Reconnaissance,localisation et suivi d'objets texturés par vision monoculaire by Nicolas Allezard( Book )

2 editions published in 2001 in French and held by 2 WorldCat member libraries worldwide

This thesis deals with textured objects recognition by monocular vision as well as their localization and tracking in the camera coordinates system. We have developed a mixed approach, based on the matching of visual primitives between the image to analyse and the images of a training base, but which uses the knowledge of the 3D object model to validate the result of the recognition process and to locate the object. In a context of textured objects the most relevant features seems to be keypoints. These points are located in image zones having a high information content. We propose a local description of such features directly based on the luminance signal. It is insensitive to image rotations ans translations and we also present a multi-scale implementation of these description in order to recognize objects in spite of important scale changes. Before the recognition, a training stage is carried out. It consists in the genration of synthetic images of the object then in the creation of a data base gathering the extracted primitives and their characterization vector. After that the data are organize in order to scan the base as fast as possible. The use of synthetics images allows them to compute the 3D coordinates of the keypoints extracted at the training stage. So, after the matching done, we obtain a set of 2D/3D pairs between the image and the object model. Thus, we compute the object position with a robust method which introduce a strong geometrical constraint on the 2D/3D pairs. In the case of a images sequence, once the object position known in the first image, the process can be considerably accelerated : the features extraction is limited to a part of the image and the data base scanning is initialized by the preceding 3D position of the object
Caractérisation et modélisation du comportement mécanique d'une plaque ondulée en composites ciment/verre by David Cherubin-Grillo( Book )

2 editions published in 2001 in French and held by 2 WorldCat member libraries worldwide

Ce travail s'inscrit dans un projet de substitution de l'amiante par la fibre de verre dans certains produits du bâtiment tels que la plaque ondulée de recouvrement. Selon une démarche d'optimisation, il s'agit ici de proposer une modification de la microstructure du matériau constitutif permettant de réduire le coût global de la plaque sans dégrader les propriétés mécaniques. La plaque d'étude présente une microstructure fortement hétérogène. Une caractérisation mécanique du matériau constitutif a été envisagée. Elle doit respecter des critères normalisés de dimensionnement. Pour un essai normalisé, l'étude expérimentale et la simulation du comportement mécanique d'une plaque ondulée ont été abordées. L'étude du matériau a révélé la sensibilité des propriétés mécaniques des composites ciment/verre à divers paramètres microstructuraux. Elle a mis en évidence une modification significative de la morphologie des porosités dans la matrice cimentaire avec la quantité et le format des microrenforts, un effet notable est obtenu sur la résistance de la matrice à la 1ère fissuration. Elle a monté également que d'autres paramètres, tels que la quantité, le format ou lorientation des renforts plus longs, ont une influence significative sur la limite à rupture du composite. L'étude expérimentale de la plaque a été menée en essai normalisé de flexion 3 points sens long. Une instrumentation spécifique a permis d'identifier les propriétés mécaniques représentatives de son comportement telles que la LOP locale et la LOP apparente. Elle a montré que l'endommagement naît et se développe essentiellement dans le creux des ondes sollicité en traction, il progresse par multifissuration. La rupture catastrophique provient de la coalescence de fissures dans la région de contrainte maximale. L'étude a révélé le creux d'onde comme région de 1ère fissuration. Pour la modélisation mécanique de la plaque ondulée, les propriétés matérielles sont déduites d'essais pratiqués sur des échantillons de plaque. La simulation a validé, notamment dans les régions de contrainte maximale, le seuil de 1ère fissuration identifié lors de l'étude expérimentale ainsi que la loi de comportement bilinéaire anisotrope injectée dans le modèle pour représenter la réponse du matériau. Une modification de la microstructure du matériau peut ainsi être considérée via les paramètres de la loi de comportement. Ce modèle simple à mettre en oeuvre permet d'étudier le comportement de la plaque à microstucture modifiée
Analyse radiative des photobioréacteurs by Jérémi Dauchet( Book )

2 editions published in 2012 in French and held by 2 WorldCat member libraries worldwide

Photosynthesis engineering is a promising mean to produce both energy carriers and fine chemicals in order to remedy the growing scarcity of fossil fuels. This is a challenging task since it implies to design process for solar biomass production associated with short time constant (few days), while oil formation took hundred million of years. This aim could be achieved by cultivating photosynthetic microorganisms in photobioreactors with optimal surface and volume kinetic performances. Above all, such an optimization necessitate a careful radiative study of the process. A radiative analysis of photobioreactors is here proposed that starts with the determination of the absorption and scattering properties of photosynthetic microorganisms suspensions, from the knowledge their morphological, metabolic and structural features. A model is constructed, implemented and validated for microorganisms with simple shapes ; the extension of this approach for the treatment of complex shapes will eventually be straightforward. Then, multiple scattering radiative transfer analysis is introduced and illustrated through different approximations that are relevant for the conceptualization of photobioreactors, leading to the construction of physical pictures that are necessary for the optimization of the process. Finally, the Monte Carlo method is implemented in order to rigorously solve multiple scattering in complex geometries (geometries that correspond to an optimized design of the process) and in order to calculate the kinetic performances of the reactor. In this trend, we develop a novel methodological development that simplies the treatment of the non-linear coupling between radiative transfer and the local kinetic of photosynthesis. These simulation tools also benefit from the most recent developments in the field of the Monte Carlo method : integral formulation, zero-variance algorithms, sensitivity evaluation (a specific approach for the evaluation of sensitivities to geometrical parameters is here developed and shown to correspond to a simple implementation in the case of a set of academic configurations that are tested). Perspectives of this work will be to take advantage of the developed analysis tools in order to stimulate the reflexion regarding photobioreactor intensification, and to extend the proposed approach to the study of photoreactive systems engineering in general
Etude des collisions d'ions lourds aux énergies du SIS et du LHC by Philippe Crochet( Book )

in English and held by 2 WorldCat member libraries worldwide

Modélisations et aptitudes à l'emploi des machines-outils à structure parallèle : vers une optimisation dirigée du processus by Sylvain Pateloup( Book )

2 editions published in 2011 in French and held by 2 WorldCat member libraries worldwide

The research works presented here deal with the prediction and the performance improvement of parallel kinematic machine tools in order to produce machine parts with a specified quality level and in a minimum time. The problem treated allows determining the structure influence on the productivity and the machined part quality in the context of High Speed Machining for automotive and aeronautical parts.So, these works propose improvements along two fundamental ways : - modelling of the machine tool anisotropic behaviour ; - new methods of process adaptation. These approaches lead in a first time to a study of the time taken by the linking tool movement between cutting operations. The developed method is based on the definition of a kinematic model of linking tool movements, specific to each machine-tool and based on a command law defined in the joint workspace. A helpful resource for the setting up of machining with a parallel kinematic machine tool is then proposed. It is based on a numerical model of the kinematic behaviour using a command law of the movement defined in the programming workspace and providing a prediction of machining time. The process optimization is also based on the machining quality prediction brought by an experimental model enhanced by a measurement campaign realized on the considered machine tool. These approaches are applied to industrial parts with the PCI Tripteor X7 machine-tool. Their originality lies in the improvement of parallel kinematic machines tool performances from an analysis of the machine behaviour during the machining, and consequently allows extending their application field
Application de méthodes probabilistes à l'analyse des couplages en Compatibilité Ealectromagnétique et contribution à la sûreté de fonctionnement de systèmes électroniques by Fatou Diouf( Book )

2 editions published in 2008 in French and held by 2 WorldCat member libraries worldwide

L'utilisation croissante d'appareils électroniques et la multiplicité des sources de perturbation ont conduit à l'étude de nouveaux moyens d'essais permettant d'améliorer la répétitivité des mesures en Compatibilité ElectroMagnétique (CEM), en particulier aux fréquences supérieures au GigaHertz. Dans ce contexte, la Chambre Réverbérente à Brassage de Modes (CRBM) représente un outil attractif, tant au niveau des mesures en immunité qu'en émission. Cependant, de nombreuses questions restent encore ouvertes quand au comportement des CRBM, en présence ou non de l'équipement sous test : les travaux représentés dans ce mémoire ont pour but d'apporter une contribution au volet probabiliste de l'étude du champ électromagnétique en CRBM
Optimisation combinatoire dans les systèmes de production : hypergraphes et méthodes d'amélioration itératives by Housni Djellab( Book )

1 edition published in 1997 in French and held by 2 WorldCat member libraries worldwide

Pratiquer une gestion efficace des systèmes de production modernes est une tâche difficile. En effet, de la conception du système à son fonctionnement performant, de nombreux problèmes, difficiles à résoudre, se posent à tous les niveaux. L'objet de cette thèse est la résolution des problèmes combinatoires de nature académique, avec certains aspects pratiques pour leur utilisation dans les ateliers de production : l'agencement des équipements en fonction des flux et l'ordonnancement, ... Une première partie est consacrée plus particulièrement à l'utilisation des hypergraphes sont la représentation des problèmes liés à la gestion des outils sur une machine à commande numérique (NC-machine) et à l'agencement des machines sur une ou plusieurs lignes. Suite à cette représentation, nous avons proposé une méthode générique pour la représentation des hypergraphes. Une étude détaillée a été faite pour le choix approprié des paramètres de la méthode dont l'adaptation a donné de bons résultats pour la gestion des outils et l'agencement. La deuxième partie consiste à ajouter, pour des travaux existants, des modules permettant d'améliorer la qualité des solutions ou de réduire le temps de calcul. Nous avons proposé pour les méthodes d'amélioration itératives (recuit simulé, recherche tabou, ...) des systèmes de voisinage guidés qui tiennent compte des caractéristiques du critère à optimiser dans le cas d'un problème de flow-shop (chaîne de montage), l'adaptation de Pecos-Solver, langage de programmation par contraintes, pour le problème de job-shop (atelier généralisé) et l'utilisation combinée des méthodes d'ordonnancement et de la simulation à événements discrets dans le cas d'un problème de job-shop sans attente (atelier généralisé a flux continu de type traitement de surface HSP)
A resource-aware embedded commucation system for highly dynamic networks by Xunxing Diao( )

1 edition published in 2011 in English and held by 1 WorldCat member library worldwide

Each year in Europe, 1,300,000 vehicle accidents result in 1,700,000 personal injuries. The financial cost of vehicle accidents is evaluated at 160 billion Euros (approximately the same cost in the USA). VANET (Vehicular Ad-Hoc NETwork) is a key technology that can enable hazard alarming applications to reduce the accident number. In addition to improve the safety for drivers and passengers, VANET can contribute to many potential applications such as detecting and predicting traffic jams, auto-optimizing the traffic flow, and helping disabled passengers to access public transports.This thesis will present an embedded communication system dedicated to VANET especially for the safety-related applications. Our design mainly tries to achieve two requirements: as one can imagine, the embedded communication system for VANET requires extra effort to deal with the highly dynamic network topology caused by moving vehicles, thus to shorten the intra-node system latency and inter-node network delay is essential requirement for such embedded communication system. Besides, a fundamental requirement for any practical embedded system is resource-awareness. Although the embedded communication system on vehicles may gain better hardware supports, the characteristics of embedded hardware still have to cope with resource constraints in terms of QoS, memory, CPU and energy. The embedded communication system involves two major software components: a routing protocol called CIVIC (Communication Inter Véhicule Intelligente et Coopérative) and an embedded operating system called HEROS (Hybrid Event-driven and Real-time multitasking Operating System). The former is a quick reaction and low resource consumption geographic protocol for inter-vehicle message transmissions; and the latter controls the whole system and assures intra-node resource awareness. In addition, the system can use a localization software solution called LCD-GPS (Low Cost Differential GPS) to improve the accuracy of locations. The hardware platform is LiveNode (LImos Versatile Embedded wireless sensor NODE), which is a versatile wireless sensor node enabling to implement rapidly a prototype for different application domains. The communication system is based on the one-hop broadcast, thus it does not have a strict limitation on network specification. For the experiments only, the IEEE 802.15.4 standard is chosen as the underlying wireless access medium. The standard is well known as a low-power consumption standard requiring low-cost devices. Notice that the IEEE 802.15.4 standard is also the wireless access medium of 6LoWPAN. Although the embedded communication system is originally designed to meet the requirements of VANET, but its application domains are not limited to VANET. For example, another network which can use the embedded communication system is WSN (Wireless Sensor Network). CIVIC was used to implement different real-world projects such MOBI+ (intelligent urban transportation system) and EU-FP6 NeT-ADDED (precision agriculture). Both VANET and WSN are highly dynamic networks, but the causes of changing network topology are different: the former is because of the high-mobility feature of vehicles, and the latter is because of the fault of wireless sensors. Note that, although VANET and WSN are both commonly considered as the subset of MANET (Mobile Ad-hoc NETwork), they are actually quite different from the classical MANET, and the similarities and differences will be further explained in the thesis. The major contribution of my works relates to the CIVIC protocol, which routes messages based on the geographic information. The related works of the thesis will focus on the geographic routing techniques, problems and solutions, but other related techniques will also be addressed. Note that, although some related projects were investigated but their implementation and experiment aspects were not detailed. (...)
Architecture générique de fusion par approche Top-Down : application à la localisation d'un robot mobile by Maroua Ladhari( )

1 edition published in 2020 in French and held by 1 WorldCat member library worldwide

The issue that will be addressed in this thesis is the localization of a mobile robot. Equipped with low- cost sensors, the robot aims to exploit the maximum possible amount of information to meet an objective set beforehand. A data fusion problem will be treated in a way that at each situation, the robot will select which information to use to locate itself in a continuous way. The data we will process will be of different types.In our work, two properties of localization are desired: accuracy and confidence. In order to be controlled, the robot must know its position in a precise and reliable way. Indeed, accuracy refers to the degree of uncertainty related to the estimated position. It is returned by a fusion filter. If, in addition, the degree of certainty of being in this uncertainty zone is important, we will have a good confidence contribution and the estimate will be considered as reliable. These two properties are generally related. This is why they are often represented together to characterize the returned estimate of the robot position. In this work, our objective is to simultaneously optimize these two properties.To take advantage of the different existing techniques for an optimal estimation of the robot position, we propose a top-down approach based on the exploitation of environmental map environmental map defined in an absolute reference frame. This approach uses an a priori selection of the best informative measurements among all possible measurement sources. The selection is made according to a given objective (of accuracy and confidence), the current robot state and the data informational contribution.As the data is noisy, imprecise and may also be ambiguous and unreliable, the consideration of these limitations is necessary in order to provide the most accurate and reliable robot position estimation. For this, spatial focusing and a Bayesian network are used to reduce the risk of misdetection. However, in case of ambiguities, these misdetections may occur. A backwards process has been developed in order to react efficiently to these situations and thus achieve the set objectives.The main contributions of this work are on one side the development of a high-level generic and modular multi sensory localization architecture with a top-down process. We used a concept of perceptual triplet which is the set of landmark, sensor and detector to designate each perceptual module. At each time, a prediction and an update steps are performed. For the update step, the system selects the most relevant triplet (in terms of accuracy and confidence) according to an informational criterion. In order to ensure an accurate and relaible localization, our algorithm has been written in such a way that ambiguity aspects can be managed.On the other side, the developed algorithm allows to locate a robot in an environment map. For this purpose, the possibility of bad detections due to ambiguity phenomena has been taken into account in the backward process. Indeed, this process allows on the one hand to correct a bad detection and on the other hand to improve the returned position estimation to meet a desired objective
Rejeu de chemin et localisation monoculaire : application du Visual SLAM sur carte peu dense en environnement extérieur contraint by Thomas Féraud( )

1 edition published in 2011 in French and held by 1 WorldCat member library worldwide

In the context of outdoor mobile robotics, concepts of localization and perception are central to any achievement. Also, the work in this thesis improves an existing localization process more robust without signicantly increasing their complexity. The proposed problematic addresses a robot in a potentially dangerous field with the aim to follow a path established as safe with a map as simple as possible. In addition, strong constraints are imposed as in the realization (inexpensive system, undetectable) as in the result (a real-time process execution and a localization continuously within a tolerance of 10 cm closed to the reference trajectory). The exteroceptive sensor chosen to carry this project is a camera while the pose estimation of the vehicle at each moment is achieved with an Extended Kalman filter. The main estimation problems are due to the non-linearity of the models and contributions provide some solutions : - an exact calculation method of the propagation of uncertainties in space world into space sensor (camera) ; - a method to detect the main event of a divergence of the update step of the Kalman filter ; - a method to correct the Kalman gain. This project had two objectives : to achieve a localization function with respect to strong constraints previously mentioned, and allow a vehicle to leave temporarily the reference trajectory, while the operator modify the robot trajectory and then resume the normal course of its mission to the reference path. This second part involves a broader context in which it is necessary, in addition to the localization, to map the environment. This problem, identifed by the acronym SLAM (Simultaneous Localization And Mapping), made the connection with the last two contributions of this thesis work : - an initialization method of the points which will constitute the SLAM map ; - a method to maintain consistency between the reference map and the SLAM map. Results on real data, supporting each contribution, are presented and illustrate the realization of the two main objectives
An integrated language for the specification, simulation, formal analysis and enactment of discrete event systems by Oumar Maïga( )

1 edition published in 2015 in English and held by 1 WorldCat member library worldwide

This thesis proposes a methodology which integrates formal methods in the specification, design, verification and validation processes of complex, concurrent and distributed systems with discrete events perspectives. The methodology is based on the graphical language HILLS (High Level Language for System Specification) that we defined. HiLLS integrates software engineering and system theoretic views for the specification of systems. Precisely, HiLLS integrates concepts and notations from DEVS (Discrete Event System Specification), UML (Unified Modeling Language) and Object-Z. The objectives of HILLS include the definition of a highly communicable graphical concrete syntax and multiple semantic domains for simulation, prototyping, enactment and accessibility to formal analysis. Enactment refers to the process of creating an instance of system executing in real-clock time. HILLS allows hierarchical and modular construction of discrete event systems models while facilitating the modeling process due to the simple and rigorous description of the static, dynamic, structural and functional aspects of the models. Simulation semantics is defined for HiLLS by establishing a semantic mapping between HiLLS and DEVS; in this way each HiLLS model can be simulated by a DEVS simulator. This approach allow DEVS users to use HiLLS as a modeling language in the modeling phase and use their own stand alone or distributed DEVS implementation package to simulate the models. An enactment of HiLLS models is defined by adapting the observer design-pattern to their implementation. The formal verification of HiLLS models is made by establishing morphisms between each level of abstraction of HILLS and a formal method adapted for the formal verification of the properties at this level. The formal models on which are made the formal verification are obtained from HILLS specifications by using the mapping functions. The three levels of abstraction of HILLS are: the Composite level, the Unitary level and the Traces level. These levels correspond respectively to the following levels of the system specification hierarchy proposed by Zeigler: CN (Coupled Network), IOS (Input Output System) and IORO (Input Output Relation Observation). We have established morphisms between the Composite level and CSP (Communicating Sequential Processes), between Unitary level and Z and we expect to use temporal logics like LTL, CTL and TCTL to express traces level properties. HiLLS allows the specification of both static and dynamic structure systems. In case of dynamic structure systems, the composite level integrates both sate-based and process-based properties. To handle at the same time state-based and process-based properties, morphism is established between the dynamic composite level and CSPZ (a combination of CSP and Z); The verification and validation process combine simulation, model checking and theorem proving techniques in a common framework. The model checking and theorem proving of HILLS models are based on an integrated tooling framework composed of tools supporting the notations of the selected formal methods in the established morphisms. We apply our methodology to modeling of the Alternating Bit Protocol (ABP) and the Automated Teller Machine (ATM)
Contribution à l'étude du comportement dynamique aléatoire de structures libres et empilées sous séïsme by Delphine Beylat( )

1 edition published in 2020 in French and held by 1 WorldCat member library worldwide

La stabilité des structures libres sous séismes est une question majeure dans l'évaluation de la sûreté des installations industrielles. Dans ces installations, certains équipements peuvent, en effet, ne pas être ancrés au sol, notamment dans les halls d'entreposage, ou être désolidarisés du sol le temps d'une opération de maintenance. Lors d'un séisme ces structures libres sont susceptibles de se renverser, de glisser, ou dans les cas les plus graves, de devenir des objets dits "missiles"pouvant blesser des personnes ou détériorer des équipements importants pour la sûreté lors d'un impact. Dans cette thèse, la structure libre étudiée est une structure industrielle représentant un empilement de trois paniers libres destinés au stockage de colis. La sensibilité inhérente au comportement non linéaire de telles structures, qui implique chocs et glissements, est une difficulté importante qui a pour conséquence que la démonstration de sûreté ne peut être envisagée que sous l'angle d'une approche probabiliste, essentiellement basée sur des calculs dynamiques temporels non linéaires. Pour ce faire, un premier modèle simplifié semi-analytique a été développé en s'inspirant de travaux récents de la littérature. Il permet d'obtenir une estimation rapide et globale de la réponse sismique de l'empilement en tenant compte des principaux phénomènes physiques qui se produisent sous une excitation unidirectionnelle.Pour obtenir plus de précision sur la réponse sismique de l'empilement, différents modèles « éléments finis » ont également été développés et une importante campagne expérimentale a été mise en oeuvre sur la table vibrante unidirectionnelle Vésuve du laboratoire EMSI du CEA de Saclay pour : (1) valider et calibrer, le cas échéant, les modèles numériques (analyses modale et sismique)et (2) évaluer la variabilité des réponses sismiques de la structure, à la fois d'un point de vue expérimental et numérique.Les deux approches -numérique et expérimentale- couplées à une approche fiabiliste, ont été menées de front pendant cette thèse et ont permis de mettre en évidence plusieurs phénomènes.D'un point de vue déterministe, les conséquences du soulèvement de la base de l'empilement sur son comportement global ont été identifiées. Il s'agit typiquement de l'augmentation de sa fréquence apparente lorsque la base se soulève, cette fréquence correspondant à la fréquence du« mode fondamental » pour lequel la base est en rotation autour de l'un de ses points d'appui.Ce travail a également montré que l'ajustement des propriétés dynamiques des modèles est une tâche essentielle, mais délicate, pour obtenir une réponse non linéaire satisfaisante. En pratique,cela signifie qu'il est difficile de connaître a priori quelles sont ces propriétés dynamiques. Néanmoins,le modèle semi-analytique peut être une alternative pour évaluer rapidement la sensibilité des modèles par rapport aux principaux paramètres physiques, bien que, dans l'absolu, cette sensibilité puisse ne pas être du même ordre d'importance d'un modèle à l'autre.De plus, comme cela est souvent observé dans les études sur le comportement sismique des structures industrielles,le mouvement de l'empilement n'était pas purement 2D, même sous une excitation unidirectionnelle.(...)
Proposition et étude d'une extension du RCPSP pour la Mutualisation entre plusieurs sites : définition, formalisation, méthodes exactes et métaheuristiques by Arnaud Laurent( )

1 edition published in 2017 in French and held by 1 WorldCat member library worldwide

Cette thèse a pour objet l'étude d'une extension du RCPSP, un problème d'ordonnancement de tâches et d'affectation de ressources. Cette extension considère un aspect multi-site au problème. Cette extension a pour but de modéliser des problématiques de mutualisation de ressources entre plusieurs sites, comme c'est notamment le cas dans les communautés hospitalières. Pour résoudre ce problème nous avons proposé des méthodes exactes ainsi que des méthodes approchées. Deux modèles mathématiques ont été proposés et comparés sur de petites instances générées. Des méthodes approchées ont également été proposées. Ces méthodes s'articulent sur un couplage méta-heuritique / algorithme d'ordre strict et permettent d'explorer un espace de recherche restreint. Trois différents codages de solution ont été proposés ainsi que trois algorithmes d'ordre strict correspondant à chacun des trois codages. Ces différentes méthodes ont été comparées et analysées selon les instances et le temps de calcul alloué
Approche probabiliste de la propagation des incertitudes dans le modèle mécano-numérique du système couplé "fémur-prothèse non cimentée" by XiaoSu Hu( )

1 edition published in 2010 in French and held by 1 WorldCat member library worldwide

The hip arthroplasty with cementless hip prosthesis is a solution usually used for the patients suffering the problems of the musculoskeletal system. However, such a solution has a major disadvantage, pointed by all users : the lack of primary stability of the prosthesis. This weakness can cause serious complications or failure of the surgery. Therefore, to achieve a good primary fixation is a crucial point of this type of surgery to ensure a short and a long term clinical satisfaction. In order to better understand this central issue, a preoperative track is adopted. A finite element model to describe the mechanical behavior of the coupled system " femur-cementless prosthesis : DePuy Corail® "has been created and validated by the experiments in vitro. Then, in order to take into account the high variability of model parameters, inherent to the nature of the problem, the stochastic modeling of random input parameters has been introduced and a mechanical-probabilistic strategy has been proposed, on the one hand to quantify, in probabilistic terms, the effect, on the response, of the uncertainties affecting the input parameters of the model, and on the other hand to evaluate the primary stability of the bone-prosthesis system in reliability context. The practical implementation of this approach is realized by using the numerical tools based on the standard Monte Carlo method and the stochastic collocation procedure. The originality of the work presented is primarily in the proposition of a probabilistic methodology capable of taking into account the uncertainties in the problem of primary stability of cementless hip prostheses. It also lies in the potentiality of this methodology to be transplantable easily in industrial context
Microsystèmes capteurs de gaz sélectifs au dioxyde d'azote associant structures semi-conducteurs et filtres chimiques (indigo ou/et nanomatériaux carbonés) destinés au contrôle de la qualité de l'air by Laurent Spinelle( )

1 edition published in 2012 in French and held by 1 WorldCat member library worldwide

This work is devoted to the study and the development of gas sensors microsystems highly selective to nitrogen dioxide, dedicated to the air quality control. The strategy developed consists in the implementation of a sensitive structure based on semiconductor materials partially selective to oxidizing gases associated to an ozone selective filter. The first objective is the development of chemical filters strictly impervious to ozone (O3) and non-reactive towards the nitrogen dioxide (NO2). We have chosen a molecular material, indigo, well-known for its reactivity towards O3, and several carbonaceous nanomaterials. For these one, the possibility to modify their textures, their morphologies and their surface chemistries by chemical, mechanical and thermic treatments, enables us to extend the range of potential materials and to identify the factors of influence on their reactivity with gaseous species. The characterization of all these materials required the use of appropriate and complementary techniques (N2 adsorption at 77 K, Raman, XPS, IR in ATR mode, EPR and NEXAFS). The more efficient filters (high filtering yield and life-time) have been selected by means of specific tests of gas exposure. Finally, the association of the best filter and the sensitive structure has led to the development of optimized gas sensors microsystems prototypes
Knowledge extraction from uncertain and cyclic time series : application to Manual Wheelchair locomotion analysis by Vanel Steve Siyou Fotso( )

1 edition published in 2018 in English and held by 1 WorldCat member library worldwide

This thesis addresses scientific issues from a data science perspective as part of the analysis of time series from manual wheelchair locomotion (FRM).Compression and classification with Dynamic Time Warping: Dyna- mic Time Warping (DTW) is a time series alignment algorithm that is often used because it considers that it exits small distortions between time series during their alignment. However, DTW sometimes produces pathological alignments that occur when, during the comparison of two time series X and Y, one data point of the time series X is compared to a large subsequence of data points of Y. In this chapter, we demonstrate that compressing time series using Piecewise Aggregate Approximation (PAA) is a simple strategy that greatly increases the quality of the alignment with DTW. This result is particularly true for synthetic data sets.Frobenius correlation based u-shapelets discovery for time series clustering: An unsupervised shapelet (u-shapelet) is a sub-sequence of a time series used for clustering a time series dataset. The purpose of this chapter is to discover u-shapelets on uncertain time series. To achieve this goal, we propose a dissimilarity score robust to uncertainty called FOTS whose computation is based on the eigen- vector decomposition and the comparison of the autocorrelation matrices of the time series. This score is robust to the presence of uncertainty; it is not very sensitive to transient changes; it allows capturing complex relationships between time series such as oscillations and trends, and it is also well adapted to the comparison of short time series. The FOTS score has been used with the Scalable Unsupervised Shapelet Discovery algorithm for the clustering of 17 datasets, and it has shown a substantial improvement in the quality of clustering with respect to the Rand Index. This work defines a novel framework for clustering of uncertain time series.Symbolic representation of cyclic time series based on properties of cycles: The analysis of cyclic time series from bio-mechanics is based on the comparison of the properties of their cycles. As usual algorithms of time series classification ignore this particularity, we propose a symbolic representation of cyclic time series based on the properties of cycles, named SAX-P. The resulting character strings can be compared using the Dynamic Time Warping distance. The application of SAX-P to propulsive moments of three subjects (S1, S2, S3) moving in Manual Wheelchair highlight the asymmetry of their propulsion. The symbolic representation SAX-P facilitates the reading of the cyclic time series and the clinical interpretation of the classification results
Les propriétés émulsifiantes du lait de chamelle et de ses fractions protéiques : étude physico-chimique et biochimique by Maroua Ellouze( )

1 edition published in 2019 in French and held by 1 WorldCat member library worldwide

Identification de la variabilité spatiale des champs de contraintes dans les agrégats polycristallins et application à l'approche locale de la rupture by Xuan Hung Dang( )

1 edition published in 2012 in French and held by 1 WorldCat member library worldwide

This thesis is a contribution to the construction of the Local Approach to fracture at the microscopic scale using polycrystalline aggregate modeling. It consists in taking into account the spatial variability of the microstructure of the material. To do this, the micromechanical modeling is carried out by finite element analysis of polycrystalline aggregates. The random stress fields (maximum principal et cleavage stress) in the material representing the spatial variability of the microstructure are then modeled by a stationary ergodic Gaussian random field. The properties of the spatial variability of these fields are identified by an identification method, e.g. periodogram method, variogram method, maximum likelihood method. The synthetic realizations of the stress fields are then simulated by a simulation method, e.g. discrete Karhunen-Loève method, circulant embedding method, spectral method, without additional finite element calculations. Finally, a Local Approach to fracture by simulation of the cleavage stress field using the simulated realizations is constructed to estimate the rupture probability of the material
Une méthode d'optimisation multicritère pour le Design For Manufacturing : application aux portes d'avion by Charles Fortunet( )

1 edition published in 2017 in French and held by 1 WorldCat member library worldwide

Nowadays, the aeronautical market grows constantly. To face this, aircraft industry has to restructure and the manufacturing processes must be revised. Indeed, production rate must increase and manufacturing cost decrease while keeping the performances of the parts (weight and mechanical resistance). These objectives are contradictory and compromises must be found. This thesis broaches this problematic in relation to the CORAC. A novel method to optimize an aeronautical structural part and its manufacturing process is developed to tend toward performing compromise solutions. To do so, a three steps multi-criteria method is proposed. First, the industrial expertise is formalized to mathematically express the problem. Then, a genetic algorithm is used to determine a population in which every solution is located on a single Pareto front. At least, a decision step is set up to find the best solution in the population considering the industrial environment of the part. This methodology is applied to an aircraft door manufactured by forging and machining. In this case, it allows choosing the solution that fit the most the industrial environment within a one thousand solutions' population
Modélisation numérique du comportement des milieux granulaires à partir de signaux pénétrométriques : approche micromécanique par la méthode des éléments discrets by Quoc Anh Tran( )

1 edition published in 2015 in French and held by 1 WorldCat member library worldwide

In the field of in situ mechanical characterization of soils, penetration tests are commonly used. Penetration tests measure the properties of soils in the domain of large deformations. The tip resistances, deduced from pile driving theory, can be measured either in dynamic conditions (q d ) either in static conditions (q c ). Recently, the measurement technique in dynamic conditions has been improved and it is now possible to record the whole response of the soil during one impact in terms of tip force and penetration distance. The exploitation of this new curve provides information not only on dynamic tip resistance but also on additional mechanical parameters involved during the driving of the tip. The objective of this work is to develop a numerical model in 2D able to reproduce the penetrometric record obtained experimentally by static or dynamic penetration tests. This model is based on the discrete element method with a simple linear contact model. After the validation of the model, a parametric study was performed essentially on the loading type (static or dynamic), the penetration rate, the particle size of the granular material and the arrangement (density variation). Besides the influence of these parameters on the penetrometer signals and the tip resistance, a particular attention was focused on micromechanical analysis: energy dissipation in the medium, force chain evolution, contact orientation. This analysis requires the development of specific numerical tools to better understand the penetration mechanism and try to explain the macroscopic mechanical response obtained. The penetration rate influences significantly only in the dense flow regime on the static and dynamic penetration tests. There is no significant microscopic difference between static and dynamic penetration tests with similar penetration rates. Regarding the influence of the characteristics of the material, the numerical results obtained conform to the real results when the particle friction or the compactness of the medium varies. Concerning the particle size, the dynamic signal variation and the dynamic tip force increases when the average particle diameter increases
 
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Audience level: 0.89 (from 0.87 for Analyse ra ... to 0.94 for Optimisati ...)

Alternative Names
École doctorale 70

École doctorale des sciences pour l'ingénieur Clermont-Ferrand

École doctorale SPI

ED 070

ED 70

ED070

ED70

EDSPI

Université Blaise Pascal Clermont-Ferrand École doctorale Sciences pour l'ingénieur

Université Blaise Pascal Clermont-Ferrand UFR Recherche scientifique et technique École doctorale Sciences pour l'ingénieur

Languages
French (21)

English (4)