WorldCat Identities

Ecole Nationale d'Ingénieurs de Sousse (Tunisie)

Overview
Works: 8 works in 8 publications in 1 language and 9 library holdings
Roles: Other
Publication Timeline
.
Most widely held works by Ecole Nationale d'Ingénieurs de Sousse (Tunisie)
Implantation matérielle de chiffrements homomorphiques by Asma Mkhinini( )

1 edition published in 2017 in French and held by 2 WorldCat member libraries worldwide

Une des avancées les plus notables de ces dernières années en cryptographie est sans contredit l'introduction du premier schéma de chiffrement complètement homomorphe par Craig Gentry. Ce type de système permet de réaliser des calculs arbitraires sur des données chiffrées, sans les déchiffrer. Cette particularité permet de répondre aux exigences de sécurité et de protection des données, par exemple dans le cadre en plein développement de l'informatique en nuage et de l'internet des objets. Les algorithmes mis en œuvre sont actuellement très coûteux en temps de calcul, et généralement implantés sous forme logicielle. Les travaux de cette thèse portent sur l'accélération matérielle de schémas de chiffrement homomorphes. Une étude des primitives utilisées par ces schémas et la possibilité de leur implantation matérielle est présentée. Ensuite, une nouvelle approche permettant l'implantation des deux fonctions les plus coûteuses est proposée. Notre approche exploite les capacités offertes par la synthèse de haut niveau. Elle a la particularité d'être très flexible et générique et permet de traiter des opérandes de tailles arbitraires très grandes. Cette particularité lui permet de viser un large domaine d'applications et lui autorise d'appliquer des optimisations telles que le batching. Les performances de notre architecture de type co-conception ont été évaluées sur l'un des cryptosystèmes homomorphes les plus récents et les plus efficaces. Notre approche peut être adaptée aux autres schémas homomorphes ou plus généralement dans le cadre de la cryptographie à base de réseaux
Diagnostic et commande tolérante aux défauts appliqués à un système de conversion électromécanique à base d'une machine asynchrone triphasée by Rebah Maamouri( )

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

The main goal of this thesis is to propose diagnostic strategies in the case of a sensorless speed control of a three-phase induction motor under an opened-switch or opened-phase fault. A qualitative analysis of the performances, in terms of stability and robustness, of sensorless control applied to the electrical drive in pre-fault and post-fault operation modes is presented. A model-based sliding mode observer is developed and experimentally validated for sensorless speed control of three-phase induction motor. The signals issued from the observer (model approach) as well as the measured ones (signal approach) are simultaneously used to form a hybrid approach for inverter open-switch fault detection and identification. A second-order sliding mode observer based on Super-Twisting algorithm (STA) is also developed to improve the stability and to ensure the continuity of operation of the electrical drive especially during transient states induced by the fault, permitting thus to apply the reconfiguration step without losing the control
Etude du comportement dynamique couplé au vieillissement des composites totalement recyclés à renfort carbone : de la caractérisation à la modélisation by Hassen Meftah( )

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

In the automotive sector, integrating more and more recycled composite materials while improving the initial performance and decreasing the carried masses becomes a compromise that needs to be addressed. Moreover, structural parts made of composite materials intended for crash are often subjected to environmental conditions, including moderately high temperatures, capable of causing gradual physico-chemical degradation. Thus, to ensure better design and durability of parts, it is important to understand the influence of thermal aging on the dynamic properties of materials. To this end, this work aims to couple the physics of oxidative degradation kinetics and the multi-scales mechanical behavior of a new fully recycled composite based on a polypropylene matrix and carbon fibers. The first axis of the study is dedicated to the elaboration, the physicochemical, microstructural and mechanical characterization of several formulations of composites. Once the optimal composite is selected, a hybrid experimental and numerical methodology is s is developed in order to characterize the dynamic properties at high strain rates reaching 100 s-1. The second axis of this work is focused on the study of the influence of thermo-oxidation on the physicochemical and mechanical properties at different strain rates of the optimal composite and its matrix. The resulting experimental has allowed the identification of a kinetic model parameters based on a mechanistic scheme. Furthermore, a qualitative and quantitative study of the effect of aging on the damage mechanisms has been carried out at a microscopic scale in order to establish a damage law linking, for a given imposed strain, the local damage density to the concentration of the oxidation products. The results of this study highlight the possibility of developing behavioral laws affected by the parameters of kinetic models describing the evolution of the physicochemical state of the composite during aging
Effet du vieillissement par fatigue électrothermique sur la compatibilité électromagnétique des composants de puissance à base de SiC by Chawki Douzi( )

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

This research work focuses on the electrothermal aging effect on the electromagnetic compatibility of power components based on silicon carbide SiC. It focuses on two major parts ; an experimental part and another more oriented modelization. Experimentally, this thesis studies the aging effect of SiC transistors used in static converters on the electromagnetic interferences EMI generated by these converters. The second part deals with the modeling of these transistors in order to emulate the effect of their aging on the EMI of the modules they compose. This step made it possible to validate the methodology developed for the simulation of the conducted EMI of a healthy SiC MOFSET at first and of an aged SiC MOSFET in a second time. Overall, this innovative modeling approach developed in this work helps the designers of static converters to predict the conducted EMI before and after aging without going through the measurement. This provides additional information on the evolution of the EMC signatures of such modules during its lifetime and thus to estimate the risk associated with the aging of the components
Contribution à la commande résiliente aux défaillances des convertisseurs statiques et à la démagnétisation de la génératrice synchrone à aimants permanents d'une hydrolienne by Sana Toumi( )

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

De nos jours, l'exploitation des énergies renouvelables afin de générer de l'électricité est en croissance soutenue puisqu'elles sont à ressource illimitée, gratuites et ne provoquent pas de déchets ou d'émissions polluantes. Dans cette thèse, on se propose d'étudier l'un de ces types d'énergie à savoir l'énergie issue des courants marins. Il s'agit plus particulièrement de s'intéresser à la commande tolérante aux défauts des systèmes de récupération de l'énergie des courants marins. Le potentiel de la production d'électricité à partir des courants marins est estimé à une production de 100 GW dans le monde. Cependant, ces chaînes de conversion d'énergie sont exposées et soumises à des contraintes fonctionnelles et environnementales importantes et sévères. Ces contraintes favorisent inévitablement la dégradation des performances des différents blocs fonctionnels de ces systèmes et l'accélération de leur processus de vieillissement, conduisant ainsi à l'apparition des défauts d'origines mécaniques et/ou électriques. Ainsi, la mise en place des techniques de commande tolérantes aux défauts de ces systèmes permettra d'améliorer la fiabilité, les performances et réduire les coûts relatifs au fonctionnement en mode dégradé et aux opérations de maintenance. Le but des travaux de cette thèse est l'étude, la modélisation et la simulation d'une chaîne de conversion hydrolienne à vitesse variable dans le cas sain et le cas d'un défaut (soit au niveau de la machine synchrone à aimants permanents (défaut de la désaimantation) ou au niveau du convertisseur statique (défaut d'un circuit ouvert d'un interrupteur). Il s'agira donc d'étudier les différentes commandes tolérantes aux défauts utilisées en cas d'un défaut au niveau de la génératrice ou au niveau de l'électronique de puissance associée
Contribution à la génération de trajectoires optimales pour les systèmes differentiellement plats application au cas d'un Quadri-rotor by Amine Abadi( )

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

In this thesis, we are interested in the autonomous navigation of robotic systems, particularly quadrotor UAV systems. We have focused on the problems related to the generation of optimal trajectories and the design of robust control to ensure tracking.In the first part of the thesis, a new method for generating trajectories is proposed. This method is based on the direct-collocation technique, differential flatness and Bézier curves.Differential flatness is used to reduce the number of parameters of the optimization problem.Bézier curves are used to approximate the flat outputs. The direct-collocation method transforms the problem of infinite optimization into a problem of nonlinear programming with finite dimension. The suggested methodology allows solving complex problems of calculating optimal trajectories in a fast, simple and efficient way, because the number of parameters will be considerably decreased, exceeding a reduction rate of 60 %.In the second part of the thesis, we put forward robust control to parametric uncertainties and external disturbances. Using flatness, the nonlinear system is transformed into a linear Brunovsky canonical form, for which it is easier to create a state feedback controller. To consider the parametric uncertainties and the external disturbances affecting the system, we propose an algorithm which uses the sliding mode and active disturbance rejection control.The simulation results show that the considered approach permits eliminating the effect oftotal disturbances and reducing the effect of chattering while ensuring the required degree of robustness.For unknown disturbances with significant variations affecting both the system and the measurements,we are interested in the last part of the thesis in developing new flatness control based on an interval observer
Caractérisation et Modélisation du comportement micromécanique des matériaux composites SMC sous chargement thermomécanique de type quasi-statique et fatigue. by Mohamed Amine Laribi( )

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

The composite materials are strongly conditioned by the ability of the company to design the automotive structures under various complexes loadings such as fatigue. The aim of this thesis is to develop a multi-scale modeling coupled to a phenomenological approach in order to provide a response to the dimensioning need of structural parts subjected to cyclic loading at different temperatures of 23°C, 80°C and -30°C. By this way, the work was conducted along two main lines; firstly, an experimental investigation under monotonic and fatigue loadings. The results of this experimental study provide the necessary data for the construction of a micromechanical model which constitute the basis of the second part of this work; the predictive approaches of the fatigue lifetime for SMC composite. Thus, two hybrid, phenomenological/micromechanical, modeling approaches have been proposed. Both are based on a micromechanical modeling that allows describing the mechanical behavior of our material under monotonic loading, taking into account the microstructure and the damage phenomenon. These two predictive models require only a limited number of experimental tests and investigations but remain very reliable in their capacity to predict the lifetime of an SMC composite material under fatigue loading. The approach is validated in the case of thermomechanical sequential loadings at variable temperatures or amplitudes
Prise en compte de la sûreté de fonctionnement lors du choix d'architectures des systèmes complexes by Anis Baklouti( )

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

The goal of this thesis is the integration of safety analysis in a model-based systems engineering approach to ensure consistency between system design and safety artifacts. This integration permits the continuous improvement of the structure and behavior of the system. It also reduces system development time and prevents late detection of errors. To reach this purpose, the SafeSysE methodology is extended. In SafeSysE, a preliminary Failure Mode and Effects Analysis (FMEA) is automatically generated from a SysML model, and this FMEA is then completed by the safety expert but no further development was proposed. The contribution of this thesis is to suggest recommendations based on the FMEA analysis in order to enhance the system design and make it comply with safety requirements. After, an updated system structure that may contain redundancy is proposed. Then, a redundancy profile is used to enrich the system model with redundancy information, which will allow the generation of a dynamic fault tree considering the system behavior. Finally, the generated dynamic fault tree should be analyzed in order to create a state machine diagram that describes the behavior of the system. The created state machine will help the system designers to better understand the system dysfunctions by simulating the system. The proposed methodology is applied to an Electro-Mechanical Actuator system and aircraft fuel distribution system which are used in the aeronautics domain
 
Audience Level
0
Audience Level
1
  General Special  
Audience level: 0.94 (from 0.87 for Diagnostic ... to 0.99 for Implantati ...)

Alternative Names
École nationale d'ingénieurs de Sousse institution universitaire en Tunisie

Eniso

National Engineering School of Sousse academic institution in Tunisia

Languages
French (8)