Dissertations / Theses on the topic 'Optimisation de tolérances'
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Gryba, Tadeusz. "Calcul des circuits électroniques VLSI avec optimisation des tolérances." Lille 1, 1985. http://www.theses.fr/1985LIL10081.
García, Gómez Sonia C. "Allocation et optimisation de tolérances géométriques par des polyédres prismatiques." Electronic Thesis or Diss., Bordeaux, 2023. http://www.theses.fr/2023BORD0504.
Geometric and dimensional deviations of mechanical components can cause problems of assemblability and/or functionality of the mechanisms. The geometric and dimensional specifications represent the limits of the manufacturing defects of a given surface. Tolerance specification is not an easy task because (i) the assigned tolerance values affect the functionalities of a system and the manufacturing cost of its parts, and (ii) design tolerances are often interrelated and contribute to a resultant tolerance.Tolerance analysis and tolerance synthesis are the two typical ways to approach the problem of tolerance design. Tolerance synthesis is traditionally seen as a "constrained optimization problem" in which the objective function is usually a cost function, a quality function or a cost-quality.In the case of over-constrained mechanisms, the interaction of the tolerances is complex and it is not possible to describe it by means of an analytical function. Hence, it is typical to do tolerance allocation instead of tolerance synthesis. The objective of the tolerance allocation is then to complete or augment the tolerance specification, originally made from experience or empirical knowledge, by incorporating some heuristics or optimization methods.In this work we show how to do tolerance allocation using the prismatic polyhedral approach as tolerance model and the simulated annealing as the heuristic optimization algorithm. In order to do this, some intermediate problems are discussed, such us (i) quality of the operands, (ii) computational time required to do a simulation and we also develop (iii) an indicator to quantify the compliance of a mechanism with its functional condition
Al-Mohammed, Mohammed. "Conception des systèmes électroniques : les étapes d'optimisation et d'allocation des tolérances." Toulouse, INPT, 2003. http://www.theses.fr/2003INPT057H.
Benichou, Sami. "Intégration des effets des dilatations thermiques dans le tolérancement." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2012. http://tel.archives-ouvertes.fr/tel-00749566.
Dumas, Antoine. "Développement de méthodes probabilistes pour l'analyse des tolérances des systèmes mécaniques sur-contraints." Thesis, Paris, ENSAM, 2014. http://www.theses.fr/2014ENAM0054/document.
Tolerance analysis of mechanism aims at evaluating product quality during its design stage. Technique consists in computing a defect probability of mechanisms in large series production. An assembly condition and a functional condition are checked. Current method mixes a Monte Carlo simulation and an optimization algorithm which is too much time consuming. The objective of this thesis is to develop new efficient method based on probabilistic approach to deal with the tolerance analysis of overconstrained mechanism. First, a linearization procedure is proposed to simplify the optimization algorithm step. The impact of such a procedure on the probability accuracy is studied. To overcome this issue, iterative procedures are proposed to deal with the assembly problem. They enable to compute accurate defect probabilities in a reduced computing time. Besides, a new resolution method based on the system reliability method FORM (First Order Reliability Method) for systems was developed for the functional problem. In order to apply this method, a new system formulation of the tolerance analysis problem is elaborated. Formulation splits up the overconstrained mechanism into several isoconstrained configurations. The goal is to consider only the main configurations which lead to a failure situation. The proposed method greatly reduces the computing time allowing getting result within minutes. Low probabilities can also be reached and the order of magnitude does not influence the computing time
Goka, Edoh. "Analyse des tolérances des systèmes complexes – Modélisation des imperfections de fabrication pour une analyse réaliste et robuste du comportement des systèmes." Thesis, Paris, ENSAM, 2019. http://www.theses.fr/2019ENAM0019/document.
Tolerance analysis aims toward the verification of the impact of individual tolerances on the assembly and functional requirements of a mechanical system. The manufactured products have several types of contacts and their geometry is imperfect, which may lead to non-functioning and non-assembly. Traditional methods for tolerance analysis do not consider the form defects. This thesis aims to propose a new procedure for tolerance analysis which considers the form defects and the different types of contact in its geometrical behavior modeling. A method is firstly proposed to model the form defects to make realistic analysis. Thereafter, form defects are integrated in the geometrical behavior modeling of a mechanical system and by considering also the different types of contacts. Indeed, these different contacts behave differently once the imperfections are considered. The Monte Carlo simulation coupled with an optimization technique is chosen as the method to perform the tolerance analysis. Nonetheless, this method is subject to excessive numerical efforts. To overcome this problem, probabilistic models using the Kernel Density Estimation method are proposed
Etienne, Alain. "Intégration Produit / Process par les concepts d'activités et de caractéristiques clés - Application à l'optimisation de l'allocation des tolérances géométriques." Phd thesis, Université de Metz, 2007. http://tel.archives-ouvertes.fr/tel-00224938.
Bruyère, Jérôme. "Contribution à l'optimisation de la conception des engrenages coniques à denture droite : analyse et synthèse de la géométrie et des tolérances." Phd thesis, Paris, ENSAM, 2006. http://pastel.archives-ouvertes.fr/pastel-00002262.
Lecomte, Christophe. "L'évaluation expérimentale des innovations variétales : proposition d'outils d'analyse de l'interaction génotype-milieu adaptés à la diversité des besoins et des contraintes des acteurs de la filière semences." Phd thesis, INAPG (AgroParisTech), 2005. http://pastel.archives-ouvertes.fr/pastel-00003471.
Dans un premier temps, des entretiens ont été effectués auprès d'une vingtaine d'acteurs impliqués dans la sélection, le développement des variétés, la multiplication, la distribution et la transformation des produits céréaliers. Ils mettent en évidence une grande diversité d'usages de I'expérimentation variétale. Quatre objectifs sous-tendent ces usages: (1) trier les génotypes, (2) les positionner géographiquement ou sur le marché, (3) acquérir une connaissance sur les génotypes, (4) et communiquer sur eux. Chaque objectif se distingue des autres par un petit nombre de critères de jugement des génotypes. Nous proposons une typologie des usages en 10 types, basée sur ces objectifs et critères, et sur les caractéristiques des réseaux expérimentaux (nombre d'essais et de génotypes, part du partenariat...). Dans chaque type, des différences peuvent être reliées à des logiques internes aux entreprises. Les entretiens mettent également en évidence un hiatus entre les informations recherchées et les informations que les acteurs tirent effectivement des expérimentations. Ce hiatus s'explique par des contraintes organisationnelles dans la mise en oeuvre des réseaux expérimentaux et par des difficultés lors du traitement des données (manque de temps disponible pour traiter les résultats; compétence requise pour I'usage d'outils d'analyse de I'interaction génotype-milieu...). Le besoin qui s'exprime le plus fortement est celui de mieux extraire I'information contenue dans les réseaux expérimentaux. Pour chacun des 10 usages, nous discutons de I'intérêt de 5 types d'outils susceptibles d'améliorer le recueil ou le traitement des données.
Afin de répondre aux souhaits de différents acteurs de valoriser l'information multilocale et d'optimiser les réseaux, un outil d'aide à I'analyse permettant d'interpréter les variations de performances des génotypes à l'échelle d'un réseau est proposé dans un second temps. Cet outil repose sur I'association d'un diagnostic agronomique, basé sur une régression linéaire multiple appliquée à des génotypes révélateurs, et d'une analyse de I'interaction par régression factorielle, appliquée à tous les génotypes. Cette association a pour but d'apporter une validation agronomique des variables explicatives de I'interaction. Selon le génotype révélateur, le diagnostic permet d'expliquer de 70 à 99% des variations de rendement pour des réseaux de 10 à 35 milieux. Chaque site expérimental est ainsi caractérisé par la nature et la contribution des facteurs limitants aux pertes de rendement. Dans I'analyse de I'interaction, les paramètres génotypiques de la régression factorielle permettent d'interpréter les variations de comportement des génotypes en terme de tolérance aux facteurs limitants. Les notes de tolérance apparaissent bien corrélées aux notes déduites des observations pour les facteurs limitants visibles comme les maladies (nous avons obtenu une corrélation de 0.9 pour la rouille brune). Cette méthode permet donc d'évaluer aussi la tolérance des génotypes aux facteurs limitants dont I'effet n'est pas facilement observable (stress hydrique, carences en azote...). En réponse aux besoins exprimés par les acteurs, et pour prendre en compte la diversité des usages de I'expérimentation variétale, nous discutons de la façon de simplifier et d'améliorer la méthode pour analyser les résultats d'essais, et nous évoquons les ajustements des pratiques actuelles d'évaluation qui pourraient être liées à I'adoption de cet outil.
Marchand, Chantal. "Optimisation de la périodicité et de la tolérance admissible des tâches de maintenance." Thèse, Université du Québec à Trois-Rivières, 2010. http://depot-e.uqtr.ca/1847/1/030147691.pdf.
Voge, Marie-Emilie. "Optimisation des réseaux de télécommunications : Réseaux multiniveaux, Tolérance aux pannes et Surveillance du trafic." Phd thesis, Université de Nice Sophia-Antipolis, 2006. http://tel.archives-ouvertes.fr/tel-00171565.
Nous nous intéressons aussi bien aux réseaux de coeur qu'aux réseaux d'accès. Dans le premier chapitre, nous présentons brièvement les réseaux d'accès ainsi que les réseaux multiniveaux de type IP/WDM et l'architecture MPLS que nous considérons pour les réseaux de coeur. Ces réseaux sont composés d'un niveau physique sur lequel est routé un niveau virtuel. A leur tour les requêtes des utilisateurs sont routées sur le niveau virtuel. Nous abordons également la tolérance aux pannes dans les réseaux multiniveaux qui motive deux problèmes que nous avons étudiés.
Le second chapitre est consacré à la conception de réseaux virtuels. Dans un premier temps nous modélisons un problème prenant en compte la tolérance aux pannes, puis nous en étudions un sous-problème, le groupage. Notre objectif est de minimiser le nombre de liens virtuels, ou tubes, à installer pour router un ensemble de requêtes quelconque lorsque le niveau physique est un chemin orienté.
Le troisième chapitre traite des groupes de risque (SRRG) induits par l'empilement de niveaux au sein d'un réseau multiniveaux. Grâce à une modélisation par des graphes colorés, nous étudions la connexité et la vulnérabilité aux pannes de ces réseaux.
L'objet du quatrième chapitre est le problème du placement d'instruments de mesure du trafic dans le réseau d'accès d'un opérateur. Nous considérons aussi bien les mesures passives qu'actives. La surveillance du trafic possède de nombreuses applications, en particulier la détection de pannes et l'évaluation des performances d'un réseau.
Voge, Marie-Émilie. "Optimisation des réseaux de télécommunications : réseaux multiniveaux, tolérance aux pannes et surveillance du trafic." Nice, 2006. http://www.theses.fr/2006NICE4085.
This thesis is devoted to optimization problems arising in telecommunication networks. We tackle these problems from two main points of view. On the one hand we study their complexity and approximability properties. On the second hand, we propose heuristic methods, approximation algorithms or even exact algorithms that we compare with mixed integer linear programming formulations on specific instances. We are interested in backbone networks as well as access networks. In the first chapter, we briefly present access networks and IP/WDM multilayer backbone networks using the MPLS architecture. These networks are composed of a physical layer on which is routed a virtual layer. In turn, the users' requests are routed on the virtual layer. We also present multilayer network survivability issues motivating two of the questions we have studied. The second chapter is dedicated to the design of virtual networks. First we propose a mixed integer linear programming formulation with network survivability constraints. Then we study a sub-problem, the grooming problem. Our objective is to minimize the number of virtual links, needed to route a given set of requests when the physical layer is a directed path. The third chapter deals with Shared Risk Resource Groups (SRRG) induced by stacking up network layers in multilayer networks. Thanks to the colored graphs model, we study connexity and failure vulnerability of these networks. The positioning of active and passive traffic measurement points in the access network of an internet service provider is the subject of the fourth chapter
Bendjedia, Bachir. "Gestion et optimisation d’énergie électrique avec tolérance aux défauts d’un système hybride PàC/ batterie." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS229.
The work of this thesis is part of a theme that concerns the optimal sizing and energy management resilient to the faults of a multi-source system (hybrid) for the power supply of an electric vehicle. In our case, the storage system consists of a fuel cell as the main source and a secondary source based on a Li-ion battery. The study carried out on the sizing shows the interest of the hybridization compared to a mono-source single battery or fuel cell only system. The interest of this hybridization in terms of weight, volume and cost becomes more and more important by increasing the autonomy of the vehicle. After scaling the hybrid source for a 700 km drive range, we investigated the influence of battery technology and management methods on the performance of the source (volume, mass, cost, electrical stress applied to the components and the hydrogen consumption of the Fuel Cell / Battery system).The sizing part is followed by the development of an original energy management strategy based on the state of charge of the battery (SOC) to adapt the operating limits of the fuel cell. The results obtained with this method are compared with two other online energy management strategies namely, the frequency division method and the use of a fuzzy supervisor. The strategy developed gave good experimental results in terms of constraints seen by cells and hydrogen consumption. Despite a good sizing of the on-board source and a good optimization of the energy management method, the system is not immune from the fault and can be the seat of several faults that can appear at voltage sensors. and current. In order to ensure the service continuity of the hybrid system in the presence of these faults, a fault-tolerant control strategy has been developed in order to guarantee the stability of the hybrid Fuel Cell/ Battery system and to ensure acceptable performance in degraded mode
Dubary, Nicolas. "Optimisation numérique et expérimentale de la tolérance aux dommages d’impact d’un stratifié composite aéronautique." Electronic Thesis or Diss., Toulouse, ISAE, 2017. http://www.theses.fr/2017ESAE0038.
Coupling with will of mass gain, use of innovative solutions and high performance structures in today’s industrial applications, composites are more and more present in aeronautical structures. However, they are still vulnerable to out-of-plane loading such as impact, due to falling objects during a maintenance operation for instance. This event can drastically reduce their residual strength without let a visible mark onto the surface. Therefore in order to meet requirements and drive to healthy use in service, composites structures are often oversized.This work deals with the experimental and numerical study of the Impact Damage Tolerance (IDT) of an aeronautical composite laminate. An overall study of composite structures integrity leads to a deeper knowledge of the IDT.The approach is based on aeronautical methods for the damages visual inspection: the damage detectability defines the required load that the structure has to sustain. Indeed, the detectability of the damage allows a repair intervention on the structure: as long as the damage is not detectable (BVID), the performance of the structure must remain high. Proposed concepts are experimentally tested to improve the TDI and to bring to more understanding in the behavior of composite laminates. These concepts are based on a reference case, and then declined under different configurations of hybrid composite laminates. The experimental approach of TDI is carried out from impact to compression after impact to define the two main indicators: permanent indentation and residual strength.The model developed at ICA, the Discrete Ply Model (DPM), is used to propose a numerical designing approach according to the TDI philosophy. Modeling improvements are implemented to extend to hybrid composite laminates. This step opens up on the use of DPM as a tool to assist the composite structures sizing. This advanced is in respect with the integration of numerical approaches to support experimental studies, integrating within the framework of "Virtual Testing"
Yahfoufi, Nassireddine. "Contribution à la tolérance aux fautes dans les applications distribuées." Versailles-St Quentin en Yvelines, 1999. http://www.theses.fr/1999VERS0005.
Chamseddine, Abbas. "Méthodologie de diagnostic et tolérance aux défauts de systèmes complexes." Aix-Marseille 3, 2007. http://www.theses.fr/2007AIX30048.
The aim of this work is to propose a methodology of fault diagnosis and fault-tolerant control for complex systems. In this work, both sensor and actuator faults are considered. The problem of complex systems instrumentation is studied. In a first step, we design a minimal number sensor network ensuring the system observability. This minimal number network verifies system's observability but it is not robust in the presence of sensor faults: the breakdown of one sensor may lead to the loss of system's observability. We propose then an approach to design a robust sensor network. Finally, we propose a methodology to design a sensor network ensuring the diagnosability of actuator faults in complex systems. These approaches are formulated as nonlinear binary optimization problems. They are illustrated and validated in simulation using a realistic model of vehicle active suspension
Guilbert, Damien. "Tolérance aux défauts et optimisation des convertisseurs DC/DC pour véhicules électriques à pile à combustible." Thesis, Belfort-Montbéliard, 2014. http://www.theses.fr/2014BELF0245/document.
Over the last years, reliability and continuity of service of powertrains have become major challenge so that the fuel cell electric vehicles (CFEV) can access to the mass automotive market. Indeed, the presence of faults in powertrains can lead up to malfunctions in the vehicle and consequently reduce its performances compared with conventional vehicles. In the case of electrical faults, powertrains of FCEV have to include fault tolerant topology and/or control for the different DC/DC and DC/AC converters. Within the framework of this research work, the study is focused on DC/DC converter combined with a Proton Exchange Membrane Fuel Cell (PEMFC). The DC/DC converter must respond to challenging issues in FCEV applications such as: low weight and small volume, high energy efficiency, fuel cell current ripple reduction and reliability. Basing on a thorough bibliographical study on non-isolated and isolated DC/DC converter topologies, an interleaved DC/DC boost converter has been chosen, meeting the FCEV requirements.The purpose of this thesis has then consisted in sizing and controlling the chosen fault-tolerant DC/DC converter topology for FCEVs. Algorithms for degraded mode management of this converter have been developed and implemented experimentally. As such, the interaction between PEMFC and interleaved DC/DC boost converter has been investigated. A theoretical approach, simulation and experimental results have been carried out to complete this work
Chêne, Charlotte. "Optimisation de l'efficacité et de la tolérance du trioxyde d'arsenic (ATO) dans les maladies fibro-inflammatoires." Electronic Thesis or Diss., Université Paris Cité, 2022. http://www.theses.fr/2022UNIP5081.
Graft-versus-Host Disease (GvHD) and systemic sclerosis (Ssc) are two pro-inflammatory pathologies that can affect different organs such as skin, lungs, the digestive tract. The severity of the diseases and the lack of effective treatment lead to the commitment of the patient's vital prognosis. It has been demonstrated in several studies that a dysregulation of the immune system is responsible for the exacerbated and chronic inflammatory response that induces fibrosis. Arsenic trioxide (ATO) is an anticancer agent used in the treatment of acute promyelocytic leukemia in humans. For several years, ATO has also been studied in clinical research for its anti-inflammatory and immunosuppressive properties, in GvHD and systemic lupus erythematosus. The encouraging results open up prospects for the use of this treatment in new indications. However, despite validation of its efficacy, ATO may present transient side effects described in some patients. We support the thesis that the association of a Fenton/Fenton-like divalent cation with a lower dose of ATO could allow to reduce its dosage. Thus the side effects would be limited while maintaining the therapeutic potential of the ATO. In a first study, ATO was associated with 8 divalent cations to evaluate in vitro the efficacy of the treatment on the production of reactive oxygen species (H2O2) and on the viability of human tumor cells (HL-60) and murine (A20). Copper was selected (CuCl2) as the most appropriate divalent cation, because when applied as a co-treatment with ATO at low dose, it potentiated the viability and the induction of oxidative stress in the 2 cell types. A mixed lymphocyte reaction was then performed in vitro to mimic the immune response observed in GvHD. Low-dose ATO + Cu2+ co-treatment, by reducing splenocyte proliferation, confirmed the choice of Cu2+. We then evaluated the effect of this co-treatment in vivo. In a mouse model of GvHD, we observed a decrease in clinical signs of the disease, cutaneous and pulmonary fibrosis, as well as digestive involvement, activation and recruitment of cells of the immune system. Treatment with low dose ATO + Cu2+ had no effect on tumor growth in a mouse model of B lymphoma. In a second study, the co-treatment was used in a mouse model of Ssc induced by repeated injections of HOCl. As in GvHD mice, the co-treatment limited the development of the disease. Low-dose ATO + Cu2+ increased oxidative stress in murine fibroblasts, impaired immune response, resulting in a significant decrease in clinical signs of Ssc. These works have demonstrated that the effect of ATO is potentiated by Cu2+, allowing to reduce the doses usually used. This work opens perspectives for clinical applications using ATO associated with a divalent cation in the treatment of pro-inflammatory diseases
Le, Bouder Gabriel. "Optimisation de la mémoire pour les algorithmes distribués auto-stabilisants." Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS002.
Self-stabilization is a suitable paradigm for distributed systems, particularly prone to transient faults. Errors such as memory or messages corruption, break of a communication link, can put the system in an inconsistent state. A protocol is self-stabilizing if, whatever the initial state of the system, it guarantees that it will return a normal behavior in finite time. Several constraints concern algorithms designed for distributed systems. Asynchrony is one emblematic example. With the development of networks of connected, autonomous devices, it also becomes crucial to design algorithms with a low energy consumption, and not requiring much in terms of resources. One way to address these problems is to aim at reducing the size of the messages exchanged between the nodes of the network. This thesis focuses on the memory optimization of the communication for self-stabilizing distributed algorithms. We establish in this thesis several negative results, which prove the impossibility to solve some problems under a certain limit on the size of the exchanged messages, by showing an impossibility to fully use the presence of unique identifiers in the network below that minimal size. Those results are generic, and may apply to numerous distributed problems. Secondly, we propose particularly efficient algorithms in terms of memory for two fundamental problems in distributed systems: the termination detection, and the token circulation
Kebbal, Djemai. "Tolérance aux fautes et ordonnancement adaptatif dans les systèmes distribués hétérogènes." Lille 1, 2000. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2000/50376-2000-316.pdf.
Bouguerra, Mohamed slim. "Tolérance aux pannes dans des environnements de calcul parallèle et distribué : optimisation des stratégies de sauvegarde/reprise et ordonnancement." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00910358.
Bouguerra, Mohamed Slim. "Tolérance aux pannes dans des environnements de calcul parallèle et distribué : optimisation des stratégies de sauvegarde/reprise et ordonnancement." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENM023/document.
The parallel computing platforms available today are increasingly larger. Typically the emerging parallel platforms will be composed of several millions of CPU cores running up to a billion of threads. This intensive growth of the number of parallel threads will make the application subject to more and more failures. Consequently it is necessary to develop efficient strategies providing safe and reliable completion for HPC parallel applications. Checkpointing is one of the most popular and efficient technique for developing fault-tolerant applications on such a context. However, checkpoint operations are costly in terms of time, computation and network communications. This will certainly affect the global performance of the application. In the first part of this thesis, we propose a performance model that expresses formally the checkpoint scheduling problem. Two variants of the problem have been considered. In the first variant, the objective is the minimization of the expected completion time. Under this model we prove that when the failure rate and the checkpoint cost are constant the optimal checkpoint strategy is necessarily periodic. For the general problem when the failure rate and the checkpoint cost are arbitrary we provide a numerical solution for the problem. In the second variant if the problem, we exhibit the tradeoff between the impact of the checkpoints operations and the lost computation due to failures. In particular, we prove that the checkpoint scheduling problem is NP-hard even in the simple case of uniform failure distribution. We also present a dynamic programming scheme for determining the optimal checkpointing times in all the variants of the problem. In the second part of this thesis, we design several fault tolerant scheduling algorithms that minimize the application makespan and in the same time maximize the application reliability. Mainly, in this part we point out that the growth rate of the failure distribution determines the relationship between both objectives. More precisely we show that when the failure rate is decreasing the two objectives are antagonist. In the second hand when the failure rate is increasing both objective are congruent. Finally, we provide approximation algorithms for both failure rate cases
Huc, Florian. "Conception de Réseaux Dynamiques Tolérants aux Pannes." Phd thesis, Université de Nice Sophia-Antipolis, 2008. http://tel.archives-ouvertes.fr/tel-00472781.
Coudert, David. "Algorithmique et optimisation dans les réseaux de télécommunications." Habilitation à diriger des recherches, Université de Nice Sophia-Antipolis, 2010. http://tel.archives-ouvertes.fr/tel-00466400.
L'ensemble des résultats présentés dans ce document est le fruit de travaux collaboratifs avec les membres de l'équipe-projet MASCOTTE, des collègues d'autres universités, française ou étrangères, et des collègues de France Télécom, Alcatel-Lucent et 3Roam. L'introduction de ce manuscrit résume nos travaux sur le routage, le groupage de trafic, la tolérance aux pannes et la reconfiguration, ainsi que des travaux plus récents sur la minimisation du nombre d'étiquettes dans les réseaux MPLS, le dimensionnement de réseaux de collecte IP sans fil, et sur le routage disjoints d'ensembles particuliers de requêtes. Ensuite, je détaille nos travaux sur le groupage de trafic au travers d'un état de l'art dans le chapitre 3, nos contributions sur la notion de groupes de ressources partageant un risque dans le chapitre 4, et sur la reconfiguration de routages dans le chapitre 5. Le chapitre 6 conclut ce manuscrit en présentant avec quelques directions de recherches.
Bourdache, Nadjet. "Élicitation incrémentale des préférences pour l’optimisation multi-objectifs : modèles non-linéaires, domaines combinatoires et approches tolérantes aux erreurs." Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS255.
This thesis work falls within the area of algorithmic decision theory, a research domain at the crossroad of decision theory, operations research and artificial intelligence. The aim is to produce interactive optimization methods based on incremental preference elicitation in decision problems involving several criteria, opinions of agents or scenarios. Preferences are represented by general decision models whose parameters must be adapted to each decision problem and each decision maker. Our methods interleave the elicitation of parameters and the exploration of the solution space in order to determine the optimal choice for the decision maker. The idea behind this is to use information provided by the elicitation to guide the exploration of the solution space and vice versa. In this thesis, we introduce new incremental elicitation methods for decision making in different contexts : first for decision making in combinatorial domains when the decision models are non-linear, and then in a setting where one takes into account the possibility of inconsistencies in the answers of te decision maker. All the algorithms that we introduce are general and can be applied to a wide range of multiobjective decision problems
Mezghani, Aïda. "Optimisation du calcul des dispersions angulaires tridimensionnelles." Phd thesis, Ecole Centrale Paris, 2010. http://tel.archives-ouvertes.fr/tel-00576363.
Diet, Ambre. "Une approche de bout en bout du tolérancement statistique sous contraintes industrielles : contribution au jumeau virtuel industriel." Thesis, Toulouse 3, 2021. http://www.theses.fr/2021TOU30014.
In the manufacturing process of a product, various assembly steps are necessary. Several types of requirements have to be met at each level and involve considerations about dimensional uncertainties on the parts to be assembled. Tolerancing is the activity in charge of the management of these uncertainties and takes place both in the product development phase and in the series production phase. In the context of the aeronautics industry, in particular with regards to tolerancing on aerostructures, specificities have to be taken into account in the development of adequate methods and tools. Prior to production, one of the main issues of tolerancing amounts to allocate tolerance limits suited to a given acceptable scrap rate. The aim is to allow the actors concerned with tolerance intervals to agree on a consistent and robust tolerance value. A statistical methodology based on a Chernov bound approach applied to a sum of uniform distributions is proposed. In the production phase, the availability of measurement data allows to refine the statistical tolerancing approach. The linear model often considered can be corrected to serve new approaches. A methodology to manage acceptance criteria on tolerance values is proposed, basing the decision support on risk concepts pertinently defined for industrial actors. Within the framework of the revision of tolerance sharing in an assembly, an optimization problem is formulated with appropriate industrial costs in order to propose the optimal tolerance re-sharing in a stack chain. Finally, the proposed methodologies are implemented in tools allowing industrial processing and end-to-end management of tolerances from elementary parts to final product assembly, thus contributing to the elaboration of the product virtual twin
Bouatit, Mohamed Nacer. "Optimisation du routage, tolérance aux pannes et gestion de l'énergie et de l'interférence pour la transmission des flux multimédia temps réel dans les réseaux de capteur sans fil." Thesis, Paris, CNAM, 2018. http://www.theses.fr/2018CNAM1188/document.
Multimedia applications in WSNs convey large data (image, audio and video) that requires high transmission rate and intensive treatment and therefore high energy consumption. Effectively transmit these heterogeneous flows, while ensuring their reliability and guaranteeing QoS requirements, with the limited resources available, especially in critical contexts, remains an open scientific problem. That is why, in this thesis, we are interested in aspects related to : routing, fault tolerance and interference management in WMSNs.Given the very low number of routing protocols, that have approached the experimental phase and still less those who approached it during data transmission in real time, we developed in this context, a geographic routing protocol baptised GNMF (Geographic Non-interfering Multipath Fault-tolerant),First, we improved node's selection mode used by the greedy-forwarding, to deal with local minimum problem, where a multi-criteria objective function (distance, energy and reception power) related to next-hop choice has been defined. Then, we introduced an optimization phase of built paths to eliminate loops and an adaptive approach to manage simultaneous traffic transmissions.After that, we oriented towards fault tolerance, to ensure transmitted data reliability and network connectivity. To this end, we modeled the number of lost packets during package delivery and proposed two mechanisms. The curative is used when sudden failures occurs and the preventive to anticipate batteries depletion. Both are combined with a dynamic failover strategy during alternative paths construction.Finally, we presented an interference model and a third mechanism that limits interactions between adjacent links. In addition, we also defined a path loss model in a multipairs environment (source, sink) and computed the error probability coefficient based on a distance function that separates the data flows. A new metric has been added in the objective function, related to noise sum of the active nodes that interferes on forwarding set nodes of the current node.Obtained results show the effectiveness of the proposed approaches that have been studied and validated both by simulation and on an experimental testbed
Bouatit, Mohamed Nacer. "Optimisation du routage, tolérance aux pannes et gestion de l'énergie et de l'interférence pour la transmission des flux multimédia temps réel dans les réseaux de capteur sans fil." Electronic Thesis or Diss., Paris, CNAM, 2018. http://www.theses.fr/2018CNAM1188.
Multimedia applications in WSNs convey large data (image, audio and video) that requires high transmission rate and intensive treatment and therefore high energy consumption. Effectively transmit these heterogeneous flows, while ensuring their reliability and guaranteeing QoS requirements, with the limited resources available, especially in critical contexts, remains an open scientific problem. That is why, in this thesis, we are interested in aspects related to : routing, fault tolerance and interference management in WMSNs.Given the very low number of routing protocols, that have approached the experimental phase and still less those who approached it during data transmission in real time, we developed in this context, a geographic routing protocol baptised GNMF (Geographic Non-interfering Multipath Fault-tolerant),First, we improved node's selection mode used by the greedy-forwarding, to deal with local minimum problem, where a multi-criteria objective function (distance, energy and reception power) related to next-hop choice has been defined. Then, we introduced an optimization phase of built paths to eliminate loops and an adaptive approach to manage simultaneous traffic transmissions.After that, we oriented towards fault tolerance, to ensure transmitted data reliability and network connectivity. To this end, we modeled the number of lost packets during package delivery and proposed two mechanisms. The curative is used when sudden failures occurs and the preventive to anticipate batteries depletion. Both are combined with a dynamic failover strategy during alternative paths construction.Finally, we presented an interference model and a third mechanism that limits interactions between adjacent links. In addition, we also defined a path loss model in a multipairs environment (source, sink) and computed the error probability coefficient based on a distance function that separates the data flows. A new metric has been added in the objective function, related to noise sum of the active nodes that interferes on forwarding set nodes of the current node.Obtained results show the effectiveness of the proposed approaches that have been studied and validated both by simulation and on an experimental testbed
Aissani, Mohamed. "Optimisation du routage dans les réseaux de capteurs pour les applications temps-réel." Phd thesis, Université Paris-Est, 2011. http://tel.archives-ouvertes.fr/tel-00664272.
Clarhaut, Joffrey. "Prise en compte des séquences de défaillances pour la conception de systèmes d'automatisation. Application au ferroutage." Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2009. http://tel.archives-ouvertes.fr/tel-00460336.
Belkadi, Adel. "Conception de commande tolérante aux défauts pour les systèmes multi-agents : application au vol en formation d'une flotte de véhicules autonomes aériens." Electronic Thesis or Diss., Université de Lorraine, 2017. http://www.theses.fr/2017LORR0183.
In recent years, the emergence of new technologies such as miniaturization of components, wireless communication devices, increased storage size and computing capabilities have allowed the design of increasingly complex cooperative multi-agent systems. One of the main research axes in this topic concerns the formation control of fleets of autonomous vehicles. Many applications and missions, civilian and military, such as exploration, surveillance, and maintenance, were developed and carried out in various environments. During the execution of these tasks, the vehicles must interact with their environment and among themselves to coordinate. The available communication tools are often limited in scope. The preservation of the connection within the group then becomes one of the objectives to be satisfied in order to carry out the task successfully. One of the possibilities to guarantee this constraint is the training displacement, which makes it possible to preserve the distances and the geometrical structure of the group. However, it is necessary to have tools and methods for analyzing and controlling these types of systems in order to make the most of their potential. This thesis is part of this research direction by presenting a synthesis and analysis of multi-agent dynamical systems and more particularly the formation control of autonomous vehicles. The control laws developed in the literature for formation control allow to carry out a large number of missions with a high level of performance. However, if a fault/failure occurs in the training, these control laws can be very limited, resulting in unstable system behavior. The development of fault tolerant controls becomes paramount to maintaining control performance in the presence of faults. This problem will be dealt with in more detail in this thesis and will concern the development and design of Fault tolerant controls devolved to a fleet of autonomous vehicles according to different configuration/structuring
Pollet, Félix. "Conception optimale de drones électriques : une approche multidisciplinaire avec analyse des incertitudes, de la tolérance aux pannes et des impacts environnementaux." Electronic Thesis or Diss., Toulouse, ISAE, 2024. http://www.theses.fr/2024ESAE0013.
Unmanned aerial vehicles (UAVs) have undergone intensive development in recent years. Owing to their cost-effectiveness and versatility, UAVs are expected to gain popularity in a wide range of applications, such as parcel delivery, power line monitoring and precision farming. Concurrently, the development of new technologies and their integration into various drone concepts is expanding the range of design alternatives. This is driving the need for holistic design approaches with better technology integration, faster development time and greater modularity.The thesis develops and implements a methodology for the conceptual design of electric multirotor, fixed-wing and hybrid vertical take-off and landing (VTOL) UAVs. The framework enables the optimal sizing of a UAV from arbitrary specifications on the mission, technological choices and architecture, using a comprehensive multidisciplinary approach.Starting from a set of analytical models including scaling laws and regressions, a generic sizing methodology is developed. The proposed methodology relies on an efficient multidisciplinary design and optimization (MDO) formulation, which enables fast convergence to the UAV candidate with best performances. In particular, the application of this approach enables to rapidly assess the effects of changes in the requirements. Next, the uncertainties surrounding the models and the availability of optimal components on the market are assessed. To mitigate critical uncertainties in UAV performance, the sizing methodology is extended to allow the design to be optimized using catalogues of existing components instead of models. Finally, the thesis develops two specific aspects of UAV design related to regulatory and societal challenges. On the one hand, recent regulations issued by the European Union Aviation Safety Agency (EASA) impose a level of safety for specific categories of UAVs. To this end, an approach is proposed to assess the controllability of various architectures in the event of failures. The assessment is further linked to the design framework to achieve fault-tolerance sizing of the rotors and control surfaces. On the other hand, societal acceptance of UAVs is strongly related to environmental concerns, including but not limited to climate change and resource consumption. This challenge is addressed by developing and integrating an environmental discipline into the design framework. The novel approach enables to assess the sensitivity of environmental impacts to mission requirements and technological assumptions, as well as minimizing environmental burdens at the earliest design stages.The thesis contributes to the development of a unified framework for optimizing the design of electric UAVs with a holistic approach. As such, it is relevant to future UAVs designed for applications subject to market, regulatory and environmental issues
Belkadi, Adel. "Conception de commande tolérante aux défauts pour les systèmes multi-agents : application au vol en formation d'une flotte de véhicules autonomes aériens." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0183/document.
In recent years, the emergence of new technologies such as miniaturization of components, wireless communication devices, increased storage size and computing capabilities have allowed the design of increasingly complex cooperative multi-agent systems. One of the main research axes in this topic concerns the formation control of fleets of autonomous vehicles. Many applications and missions, civilian and military, such as exploration, surveillance, and maintenance, were developed and carried out in various environments. During the execution of these tasks, the vehicles must interact with their environment and among themselves to coordinate. The available communication tools are often limited in scope. The preservation of the connection within the group then becomes one of the objectives to be satisfied in order to carry out the task successfully. One of the possibilities to guarantee this constraint is the training displacement, which makes it possible to preserve the distances and the geometrical structure of the group. However, it is necessary to have tools and methods for analyzing and controlling these types of systems in order to make the most of their potential. This thesis is part of this research direction by presenting a synthesis and analysis of multi-agent dynamical systems and more particularly the formation control of autonomous vehicles. The control laws developed in the literature for formation control allow to carry out a large number of missions with a high level of performance. However, if a fault/failure occurs in the training, these control laws can be very limited, resulting in unstable system behavior. The development of fault tolerant controls becomes paramount to maintaining control performance in the presence of faults. This problem will be dealt with in more detail in this thesis and will concern the development and design of Fault tolerant controls devolved to a fleet of autonomous vehicles according to different configuration/structuring
Ecault, Romain. "Etude expérimentale et numérique du comportement dynamique de composites aéronautiques sous choc laser. Optimisation du test d'adhérence par ondes de choc sur les assemblages composites collés." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2013. http://www.theses.fr/2013ESMA0031/document.
This work aims the development of a non-destructive technique to control the mechanical quality ofaeronautics adhesive bonds (ENCOMB project). Shocks were realized by use of laser sources or gas gun, anddifferent techniques were used to analyse the shocks such as: VISAR, PDV, Shadowgraphy, optical andconfocal microscopy, X-ray radiography, ultrasound testing…Epoxy resins and carbon/epoxy compositelaminates were first investigated. Monitored laser shocks, in addition to post-mortem analyses, enabled tobetter understand the shock phenomenon on these complex materials. The results obtained on bondedcomposite showed that the laser shock technique can be used to discriminate different adherence levels.The use of numerical models, developed thanks to the experimental data, enabled to analyze the shockpropagation in these complex assemblies. They also evidenced the need for optimization, in order to testonly the bond interface and not to break the composite parts on the assembly. Several optimizationsolutions are formulated such as the use of tuneable pulse duration, or double shock configurations. Someof these solutions have been experimentally validated, and the numerical optimization gives the shockparameters to use for the next experimental campaigns. Finally, this work provides original results on thedynamic behaviour of composite materials under laser shock and leads to the adaptation of the laser shockadhesion test to any kind of bonded composite assemblies
Tran, Dinh Tin. "Optimisation du processus du contrôle métrologique des pièces mécaniques dans le cadre d’une analyse 3D du tolérancement." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0082/document.
As part of the design and manufacturing of industrial products, we mainly find the steps of design, manufacture and control. The designer choose functional tolerancing values and specification for a part closely with manufacturing processes. The step of the control of parts is then an essential stage of the validation of the product made with respect to the needs of the designer. The research subject is placed in order to optimize process control parts. This optimization should be done at several levels: - In terms of costs to the measurement process: when an operator sets its control methodology, he validates if possible the entire piece on a unique way to measure it, even if the measurement device selected is not the most appropriate. This part of the study concerns the concepts of capability of measuring devices and calculation methods. It will define the limits of each machine. The analysis of the adequacy between the tolerancing specifications and the measurement tools also allows the controller to define a strategy for economic measurement (time, equipment, ...). - In terms of technical innovations to be taken into account: we will use simultaneously a finite element software, (Abaqus, for modeling the deformations of parts during the control process) and a software for tolerances analysis, (3DCS, to validate the effects of the dispersions of the measurement device over the validity of the result of the measure : measurement uncertainty)
Aissani, Mohamed. "Optimisation du routage dans les réseaux de capteurs pour les applications temps-réel." Electronic Thesis or Diss., Paris Est, 2011. http://www.theses.fr/2011PEST1001.
Resolution of the void-problem in geographical routing in Wireless Sensor Networks (WSN) is an open problem and it can be considered as key issue in disseminating data from sensor nodes to sinks. In this thesis, unlike previously-proposed methods, we address this problem in a different manner by proposing a novel approach to handle both voids and real-time flows with optimizing energy-efficiency of deployed nodes in a WSN. The proposed approach is based on the geographic information of the current node, of the neighbor voids and of the sink. Our proposal relies on the mechanisms that discover voids, announce them and then maintain them. The first proposed protocol, called VT-SPEED, is based on an adaptive void-avoidance mechanism that considers both load of routing candidate nodes and their localization information. To make VT-SPEED energy-aware, we also propose new routines based on parameterized functions that handle routing dissipation energy : (a) dropping out-of-order packets and (b) load-balancing when choosing next hop of packets. The resulting protocol, called VE-SPEED, has satisfactory results which show that the proposed approach satisfies the real-time constraints of data flows, tolerates voids, preserves energy resources of boundary nodes, balances load between nodes and has optimal energy consumption
Yacoub, Mohamed. "Conception des systèmes : calculs technico-économiques et aide à la décision dans la conduite d'un projet "recherche"." Toulouse 3, 2004. http://www.theses.fr/2004TOU30064.
The increasing requirements in management of Research & Development invite to implement a methodology of specific project control. Indeed, it has obvious characteristics: to be very closed with the innovation and very far from the stages of industrialization and marketing. The methodology of control that we explored is to base the decisions on a technico-economic modelling in the long-term, to take into account the technological development in the form of optimization stages or selection of scenarios producing the specified target for the project. Long-term modelling is carried out by the coupling of the tools: Microsoft Project, for planning and WinNag, for economic and financial evaluation We propose that the establishment of the planning is based on the definition of the functions established by the design upstream and associating the non-functional data with it:. .
Medjiah, Samir. "Optimisation des protocoles de routage dans les réseaux multi-sauts sans fil à contraintes." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14663/document.
Great research efforts have been carried out in the field of challenged multihop wireless networks (MWNs). Thanks to the evolution of the Micro-Electro-Mechanical Systems (MEMS) technology and nanotechnologies, multihop wireless networks have been the solution of choice for a plethora of problems. The main advantage of these networks is their low manufacturing cost that permits one-time application lifecycle. However, if nodes are low-costly to produce, they are also less capable in terms of radio range, bandwidth, processing power, memory, energy, etc. Thus, applications need to be carefully designed and especially the routing task because radio communication is the most energy-consuming functionality and energy is the main issue for challenged multihop wireless networks.The aim of this thesis is to analyse the different challenges that govern the design of challenged multihop wireless networks such as applications challenges in terms of quality of service (QoS), fault-tolerance, data delivery model, etc., but also networking challenges in terms of dynamic network topology, topology voids, etc. Our contributions in this thesis focus on the optimization of routing under different application requirements and network constraints. First, we propose an online multipath routing protocol for QoS-based applications using wireless multimedia sensor networks. The proposed protocol relies on the construction of multiple paths while transmitting data packets to their destination, i.e. without prior topology discovery and path establishment. This protocol achieves parallel transmissions and enhances the end-to-end transmission by maximizing path bandwidth and minimizing the delays, and thus meets the requirements of QoS-based applications. Second, we tackle the problem of routing in mobile delay-tolerant networks by studying the intermittent connectivity of nodes and deriving a contact model in order to forecast future nodes' contacts. Based upon this contact model, we propose a routing protocol that makes use of nodes' locations, nodes' trajectories, and inter-node contact prediction in order to perform forwarding decisions. The proposed routing protocol achieves low end-to-end delays while using efficiently constrained nodes' resources in terms of memory (packet queue occupancy) and processing power (forecasting algorithm). Finally, we present a topology control mechanism along a packet forwarding algorithm for event-driven applications using stationary wireless sensor networks. Topology control is achieved by using a distributed duty-cycle scheduling algorithm. Algorithm parameters can be tuned according to the desired node's awake neighbourhood size. The proposed topology control mechanism ensures trade-off between event-reporting delay and energy consumption
Kolli, Abdelfatah. "ANALYSE D'UNE ARCHITECTURE DE PUISSANCE DÉDIÉE AUX MODES TRACTION-RECHARGE DANS UN VÉHICULE ÉLECTRIQUE. Optimisation de la commande et fonctionnement en mode dégradé." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00938394.
Kolli, Abdelfatah. "Analyse d’une architecture de puissance dédiée aux modes traction–recharge dans un véhicule électrique. Optimisation de la commande et fonctionnement en mode dégradé." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112316/document.
This Ph.D. thesis focuses on a novel combination of a frequency converter and an electric machine specially dedicated to traction drive and battery recharging modes of an electric vehicle (EV). This power architecture is composed of a six legs voltage inverter connected to a three-phase open-end winding machine. Chapter II details a quantitative comparison between two industrial power architectures and concludes that the SOFRACI powertrain is a competitive solution in terms of power converter efficiency, drive mechanical performances, and required silicon area.This architecture offers the attractive possibility of combining three important functions: traction and braking, battery charging and connecting the energy storage to a smart grid. In addition, this topology offers several advantages such as various motor feeding possibilities and a high degree of reconfiguration in degraded operating mode. The third and fourth chapters of this thesis concern the optimization of control strategies with regard to two types of faults: firstly the inherent imperfections in the converter itself (non modeled non-linearity and ineffective synchronization of control values) and secondly accidental failures. In the first case, an analysis of the pulse width modulation (PWM) methods enables the creation of a PWM strategy with a very low sensitivity to PWM uncertainties and the non-linear behavior of the power converter.In the second case, in the event of a faulty semiconductor device, it is shown that a hardware reconfiguration is required to enable an emergency traction mode. The sustainability of the traction mode is then examined with respect to the control strategy. This analysis leads to an innovative control structure based on basic and easy to implement solutions. Finally, the degraded mode operation principles have been extended to normal mode operation for the purpose of enhancing the cycle efficiency
Zotkiewicz, Mateusz. "Robust routing optimization in resilient networks : Polyhedral model and complexity issues." Thesis, Evry, Institut national des télécommunications, 2011. http://www.theses.fr/2011TELE0001/document.
In the thesis robust routing design problems in resilient networks are considered. In the first part computational complexity of such problems are discussed. The following cases are considered: - path protection and path restoration - failure-dependent and failure-independent restoration - cases with and without stub-release - single-link failures and multiple-link failures (shared risk link group) - non-bifurcated (unsplittable) flows and bifurcated flows For each of the related optimization cases a mixed-integer (in the non-bifurcated cases) or linear programming formulation (in all bifurcated cases) is presented, and their computational complexity is investigated. For the NP-hard cases original NP-hardness proofs are provided, while for the polynomial cases compact linear programming formulations (which prove the polynomiality in the question) are discussed. Moreover, pricing problems related to each of the considered NP-hard problems are discussed. The second part of the thesis deals with various routing strategies in networks where the uncertainty issues are modeled using the polyhedral model. In such networks two extrema are possible. The simplest in terms of implementation, and simultaneously the least effective strategy, is the robust stable routing. On the other hand, the most effective strategy, i.e., the dynamic routing, is virtually impossible to implement in real world networks. Therefore, the major aim of this part of the thesis is to present novel routing strategies that merge the simplicity of the robust stable routing with the efficiency of the dynamic routing
Clarhaut, Joffrey. "Prise en compte des séquences de défaillances pour la conception de systèmes d’automatisation : Application au ferroutage." Electronic Thesis or Diss., Lille 1, 2009. http://www.theses.fr/2009LIL10009.
This thesis deals with a design problem of dependable automated systems using scenarios. In order to determine an optimal system, having fast tools for modelling and evaluating dependability is important. These tools allow the set of possible architectures to be evaluated, and the impact of failures to be studied. The main considered questions include the determination of an equipment architecture, its optimization according to such criteria as the minimal length of scenarios, and its number of combinations. A new graphical model, called improved multi fault tree, which is enough accurate to model component organizations and scenarios, is proposed for this problem. This model uses temporal operators and failure relationships to model system’s behaviour in presence of multiple failures. Application of this method to the railroad piggybacking transportation system is also presented. Results obtained for a fire detection and a stowing protection system are presented. A comparison between the proposed approach and the classical dependability approach shows the benefits of this new methodology. The integration of this research in a software for designing dependable automated systems (ALoCSyS) is described
Clarhaut, Joffrey. "Prise en compte des séquences de défaillances pour la conception de systèmes d’automatisation : Application au ferroutage." Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10009/document.
This thesis deals with a design problem of dependable automated systems using scenarios. In order to determine an optimal system, having fast tools for modelling and evaluating dependability is important. These tools allow the set of possible architectures to be evaluated, and the impact of failures to be studied. The main considered questions include the determination of an equipment architecture, its optimization according to such criteria as the minimal length of scenarios, and its number of combinations. A new graphical model, called improved multi fault tree, which is enough accurate to model component organizations and scenarios, is proposed for this problem. This model uses temporal operators and failure relationships to model system’s behaviour in presence of multiple failures. Application of this method to the railroad piggybacking transportation system is also presented. Results obtained for a fire detection and a stowing protection system are presented. A comparison between the proposed approach and the classical dependability approach shows the benefits of this new methodology. The integration of this research in a software for designing dependable automated systems (ALoCSyS) is described
Socoliuc, Michel. "Introduction et analyse des schémas de cotation en avance de phase." Phd thesis, Ecole Centrale Paris, 2010. http://tel.archives-ouvertes.fr/tel-00534810.
Bentria, Dounia. "Combining checkpointing and other resilience mechanisms for exascale systems." Thesis, Lyon, École normale supérieure, 2014. http://www.theses.fr/2014ENSL0971/document.
In this thesis, we are interested in scheduling and optimization problems in probabilistic contexts. The contributions of this thesis come in two parts. The first part is dedicated to the optimization of different fault-Tolerance mechanisms for very large scale machines that are subject to a probability of failure and the second part is devoted to the optimization of the expected sensor data acquisition cost when evaluating a query expressed as a tree of disjunctive Boolean operators applied to Boolean predicates. In the first chapter, we present the related work of the first part and then we introduce some new general results that are useful for resilience on exascale systems.In the second chapter, we study a unified model for several well-Known checkpoint/restart protocols. The proposed model is generic enough to encompass both extremes of the checkpoint/restart space, from coordinated approaches to a variety of uncoordinated checkpoint strategies. We propose a detailed analysis of several scenarios, including some of the most powerful currently available HPC platforms, as well as anticipated exascale designs.In the third, fourth, and fifth chapters, we study the combination of different fault tolerant mechanisms (replication, fault prediction and detection of silent errors) with the traditional checkpoint/restart mechanism. We evaluated several models using simulations. Our results show that these models are useful for a set of models of applications in the context of future exascale systems.In the second part of the thesis, we study the problem of minimizing the expected sensor data acquisition cost when evaluating a query expressed as a tree of disjunctive Boolean operators applied to Boolean predicates. The problem is to determine the order in which predicates should be evaluated so as to shortcut part of the query evaluation and minimize the expected cost.In the sixth chapter, we present the related work of the second part and in the seventh chapter, we study the problem for queries expressed as a disjunctive normal form. We consider the more general case where each data stream can appear in multiple predicates and we consider two models, the model where each predicate can access a single stream and the model where each predicate can access multiple streams
Chevallier, Christ-Yves. "Conception de miroirs à réseau sub-longueur d'onde pour application VCSEL dans le moyen infrarouge." Phd thesis, Supélec, 2013. http://tel.archives-ouvertes.fr/tel-01024257.
Liu, Xinyi. "Contribution to adaptative sliding mode, fault tolerant control and control allocation of wind turbine system." Thesis, Belfort-Montbéliard, 2016. http://www.theses.fr/2016BELF0295/document.
The main challenges for the deployment of wind energy conversion systems (WECS) are to maximize the amount of good quality electrical power extracted from wind energy over a significantly wide range of weather conditions and minimize both manufacturing and maintenance costs. Wind turbine's efficiency is highly dependent on environmental disturbances and varying parameters for operating conditions, such as wind speed, pitch angle, tip-speed ratio, sensitive resistor and inductance. Uncertainties on the system are hard to model exactly while it affects the stability of the system. In order to ensure an optimal operating condition, with unknown perturbations, adaptive control can play an important role. On the other hand, a Fault Tolerant Control (FTC) with control allocation that is able to maintain the WECS connected after the occurrence of certain faults can avoid major economic losses. The thesis work concerns the establishment of an adaptive control and fault diagnosis and tolerant control of WECS. After a literature review, the contributions of the thesis are:In the first part of the thesis, a nonlinear uncertain model of the wind energy conversion system with a doubly fed induction generator (DFIG) is proposed. A novel Lyapunov-based adaptive Sliding Mode (HOSM) controller is designed to optimize the generated power.In the second part, a new output integral sliding mode methodology for fault tolerant control with control allocation of linear time varying systems is presented. Then, this methodology has been applied in order to force the wind turbine speed to its optimal value the presence of faults in the actuator
Shehaj, Marinela. "Robust dimensioning of wireless optical networks with multiple partial link failures." Thesis, Compiègne, 2020. http://www.theses.fr/2020COMP2540.
This thesis summaries the work we have done in optimization of wireless optical networks. More specifically, the main goal of this work is to propose appropriate network dimensioning algorithms for managing the demand and ensuring traffic satisfaction in a network under partial link failures (i.e. when some links and/or nodes are operational with reduced capacity) caused mostly by weather conditions. The primary criterion in deciding the efficiency of the proposed algorithms for the network is the dimensioning cost of the network while keeping the traffic satisfaction at high reasonable levels. The main application area we have in mind are the networks that apply Free Space Optics (FSO) - a well established broadband wireless optical transmission technology where the communication links are provided by means of a laser beam sent from the transmitter to the receiver placed in the line of sight. FSO networks exhibit several important advantages but the biggest disadvantage is vulnerability of the FSO links to weather conditions, causing substantial loss of the transmission power over optical channel. This makes the problem of network dimensioning important, and, as a matter of fact, di cult. Therefore, a proper approach to FSO network dimensioning should take such losses into account so that the level of carried traffic is satisfactory under all observed weather conditions. In this thesis, we firstly describe such an approach. In the first part of the thesis, we introduce a relevant dimensioning problem and present a robust optimization algorithm for such enhanced dimensioning. To construct our approach we start with building a reference failure set which uses a set of weather data records for a given time period against which the network must be protected. Next, a mathematical model formulation of the robust network dimensioning problem uses the above failure set. Yet, such obtained reference set will most likely contain an excessive number of states and at the same time will not contain all the states that will appear in the reality. Hence, we propose to approximate the reference failure set with a special kind of virtual failure set called K-set parameterized by an integer value K, where K is less than or equal to the number of all links in the network. For a given K, the K-set contains all states corresponding to all combinations of K, or less, simultaneously affected links. Sometimes, there are situations where the weather is extremely bad and what we propose is to build a hybrid network model composed of FSO and fiber links. The second part of this thesis is devoted to the improvement of the so-called uncertainty sets (or uncertainty polytopes). In the first part we have introduced the idea of link Ksets. Now we extend this by considering simultaneous degradations of K nodes (meaning degradation of all adjacent links). Finally, inspired by the hitting set problem a new idea was to find a large number of subsets of two or three affected links and to use all possible combinations (composed of 2 or at most 3 of this subsets) to build a new virtual failure set that covers as much as possible the reference failure set that we got from the study of real weather data records. Next, this new failure set will serve as input for our cut-generation xxi algorithm so that we can dimension the network at a minimum cost and for a satisfactory demand realization. A substantial part of the work is devoted to present numerical study for different network instances that illustrates the effectiveness of the proposed approach. A dedicated space is given to the construction of a realistic network instance called Paris Metropolitan Area Network (PMAN)
Magot, David. "METHODES ET OUTILS LOGICIELS D'AIDE AU DIMENSIONNEMENT. APPLICATION AUX COMPOSANTS MAGNETIQUES ET AUX FILTRES PASSIFS." Phd thesis, 2004. http://tel.archives-ouvertes.fr/tel-00389262.