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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Design Optimization Of A Parallel Hybrid Powertrain Using Derivative-Free Algorithms

Porandla, Sachin Kumar 10 December 2005 (has links)
A Hybrid Electric Vehicle (HEV) is a complex electro-mechanical-chemical system that involves two or more energy sources. The inherent advantages of HEVs are their increased fuel economy, reduced harmful emissions and better vehicle performance. The extent of improvement in fuel economy and vehicle performance greatly depends on selecting optimal component sizes. The complex interaction between the various components makes it difficult to size specific components manually or analytically. So, simulation-based multi-variable design optimization is a possible solution for such kind of system level design problems. The multi-modal, noisy and discontinuous nature of the Hybrid Vehicle design requires the use of derivativeree global algorithms because the derivative-based local algorithms work poorly with such design problems. In this thesis, a Hybrid Vehicle is optimized using various Global Algorithms ? DIviding RECTangles (DIRECT), Simulated Annealing (SA), Genetic Algorithm (GA), and Particle Swarm Optimization (PSO). The objective of this study is to increase the overall fuel economy on a composite of city and highway driving cycle and to improve the vehicle performance. The performance of each algorithm is compared on a six variable hybrid electric vehicle design problem. Powertrain System Analysis Tool (PSAT), a state-of-the-art powertrain simulator, developed in MATLAB/Simulink environment by Argonne National Laboratory is used as the vehicle simulator. Further, a Hybrid algorithm that is a combination of global and local algorithm is developed to improve the convergence of the global algorithms. The hybrid algorithm is tested on two simple mathematical functions to check its efficiency.
2

Application des architectures many core dans les systèmes embarqués temps réel / Implementing a Real-time Avionic application on a Many-core Processor

Lo, Moustapha 22 February 2019 (has links)
Les processeurs mono-coeurs traditionnels ne sont plus suffisants pour répondre aux besoins croissants en performance des fonctions avioniques. Les processeurs multi/many-coeurs ont emergé ces dernières années afin de pouvoir intégrer plusieurs fonctions et de bénéficier de la puissance par Watt disponible grâce aux partages de ressources. En revanche, tous les processeurs multi/many-coeurs ne répondent pas forcément aux besoins des fonctions avioniques. Nous préférons avoir plus de déterminisme que de puissance de calcul car la certification de ces processeurs passe par la maîtrise du déterminisme. L’objectif de cette thèse est d’évaluer le processeur many-coeur (MPPA-256) de Kalray dans un contexte industriel aéronautique. Nous avons choisi la fonction de maintenance HMS (Health Monitoring System) qui a un besoin important en bande passante et un besoin de temps de réponse borné.Par ailleurs, cette fonction est également dotée de propriétés de parallélisme car elle traite des données de vibration venant de capteurs qui sont fonctionnellement indépendants, et par conséquent leur traitement peut être parallélisé sur plusieurs coeurs. La particularité de cette étude est qu’elle s’intéresse au déploiement d’une fonction existante séquentielle sur une architecture many-coeurs en partant de l’acquisition des données jusqu’aux calculs des indicateurs de santé avec un fort accent sur le fluxd’entrées/sorties des données. Nos travaux de recherche ont conduit à 5 contributions:• Transformation des algorithmes existants en algorithmes incrémentaux capables de traiter les données au fur et mesure qu’elles arrivent des capteurs.• Gestion du flux d’entrées des échantillons de vibrations jusqu’aux calculs des indicateurs de santé,la disponibilité des données dans le cluster interne, le moment où elles sont consommées et enfinl’estimation de la charge de calcul.• Mesures de temps pas très intrusives directement sur le MPPA-256 en ajoutant des timestamps dans le flow de données.• Architecture logicielle qui respecte les contraintes temps-réel même dans les pires cas. Elle estbasée sur une pipeline à 3 étages.• Illustration des limites de la fonction existante: nos expériences ont montré que les paramètres contextuels de l’hélicoptère tels que la vitesse du rotor doivent être corrélés aux indicateurs de santé pour réduire les fausses alertes. / Traditional single-cores are no longer sufficient to meet the growing needs of performance in avionics domain. Multi-core and many-core processors have emerged in the recent years in order to integrate several functions thanks to the resource sharing. In contrast, all multi-core and many-core processorsdo not necessarily satisfy the avionic constraints. We prefer to have more determinism than computing power because the certification of such processors depends on mastering the determinism.The aim of this thesis is to evaluate the many-core processor (MPPA-256) from Kalray in avionic context. We choose the maintenance function HMS (Health Monitoring System) which requires an important bandwidth and a response time guarantee. In addition, this function has also parallelism properties. It computes data from sensors that are functionally independent and, therefore their processing can be parallelized in several cores. This study focuses on deploying the existing sequential HMS on a many-core processor from the data acquisition to the computation of the health indicators with a strongemphasis on the input flow.Our research led to five main contributions:• Transformation of the global existing algorithms into a real-time ones which can process data as soon as they are available.• Management of the input flow of vibration samples from the sensors to the computation of the health indicators, the availability of raw vibration data in the internal cluster, when they are consumed and finally the workload estimation.• Implementing a lightweight Timing measurements directly on the MPPA-256 by adding timestamps in the data flow.• Software architecture that respects real-time constraints even in the worst cases. The software architecture is based on three pipeline stages.• Illustration of the limits of the existing function: our experiments have shown that the contextual parameters of the helicopter such as the rotor speed must be correlated with the health indicators to reduce false alarms.

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