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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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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.
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Showing 111 to 118 of 118 (0.041 seconds)| 111 |
Commande optimale d’une voiture électrique à faible consommation sous contraintes temps réel / Real-time optimal control of a low consumption electric vehicle.Manrique Espindola, Dolly Tatiana 09 December 2014 (has links)
Le problème de l'efficacité énergétique dans le domaine des transports a comme principal défi savoir comment utiliser la source d'énergie pour que l'efficacité énergétique puisse être maximisée, c'est-à-dire comment le véhicule doit être conduit de telle sorte que la quantité minimale d’énergie est utilisée. Ce problème est le principal problème considéré dans cette thèse. Le véhicule est un prototype impliqué dans la course européenne Shell Eco-Marathon. La dynamique du véhicule est d'abord obtenu par l'identification expérimentale des paramètres. Une stratégie en boucle ouverte de conduite optimale en termes de consommation électrique est calculée. Plusieurs approches ont été étudiées pour le suivi de la référence optimale (stratégie de conduite optimale). Ces approches doivent prendre en compte les ressources limitées en taille mémoire et capacité de calcul. Une commande prédictive (MPC) basée sur la dynamique linéarisée est tout d'abord synthétisée. Le problème de poursuite nécessite une MPC avec contraintes variant dans le temps. La stabilité et la convergence de la commande prédictive sont prouvées à l'aide du formalisme des ensembles invariants. En troisième partie, à partie du modèle LPV, une adaptation de techniques standards basées sur des fonctions de Lyapunov quadratiques et à paramètres variants avec calculs hors-ligne est proposée. Elle est implémentée sur un banc de test. Enfin, une technique adaptative robuste avec identification en ligne de la dynamique est proposée et implémentée dans le véhicule. Cette technique a été testée et validée en course. Les résultats expérimentaux obtenus montrent de bonnes performances de la stratégie de conduite / In the field of transportation, the research on energy efficiency has been carried out for few decades by the automotive industry, where one of the main objectives is to reduce the energetic consumption. This particular problem can be rephrased as how the vehicle must be driven so that the minimum quantity of energy is used. This is the optimal driving strategy. In this project, a suitable model of the Vir'volt electric vehicle involved in the European Shell Eco-Marathon is obtained. The unknown parameters involved in the vehicle dynamics are estimated using Parameter identification from experimental data. The identified dynamics is used to derive an optimal driving strategy that is intended to be tracked on-line during the driving task. The tracking task is subject to time-varying polytopic constraint on the input and/or the state. A MPC-based tracking strategy that uses an homothetic transformation as a suitable time-varying invariant set is used. The time-varying invariant set guarantees the asymptotic stability of the control law. The problem of the MPC tracking for Linear Parametric Varying (LPV) systems is introduced. A new explicit MPC strategy for LPV systems is developed. This strategy uses a Parameter dependent Lyapunov Function (PDLF) to involve explicitly the time-varying parameter in the control law and so it reduces conservatism. A benchmark is used to test the performances of the optimal driving strategy and the explicit MPC tracking strategy. Finally, a robust adaptive technique with on-line identification of the dynamics is has been proposed and tested in the race showing good performances of the adaptive driving strategy
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Psychosocial factors and susceptibility to the common cold in distance runnersStruwig, Gillian Anne 30 November 2004 (has links)
This study investigated the relationship between specific psychosocial factors and susceptibility to the common cold in a sample of 124 distance runners. A cross-sectional survey design was used to assess the role of life events, coping, hardiness, training workload and competition frequency in the athlete's risk of infection. Using correlational statistical techniques, it was found that the magnitude of recent life changes and the avoidance coping strategy of denial were positively related to self-reported symptoms of the common cold. Furthermore, a significant inverse correlation was observed between hardiness and symptom duration scores. However, approach coping, training workload and competition frequency were not significantly related to the dependent measures. The results of this study suggest that certain stress-related psychosocial factors are associated with susceptibility to the common cold in distance runners. Several strategies for the prevention and treatment of upper respiratory tract infections in this group are implied by these findings. / Psychology / M.A. (Psychology)
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Renewing Athens : the ideology of the past in Roman GreeceMcHugh, Sarah January 2017 (has links)
In this thesis we explore the period of renewal that Athens experienced during the second century AD. This century saw Athens at the peak of her cultural prominence in the Roman Empire: the city was the centre of the League of the Panhellenion and hosted a vibrant sophistic scene that attracted orators from across the Greek world, developments which were ideologically fuelled by contemporary conceptions of Classical Athens. While this Athenian 'golden age' is a standard feature of scholarship on Greek culture under Rome, my thesis delves further to explore the renewal of the urban and rural landscapes at this time and the relationship between that process and constructions of Athenian identity. We approach the renewal of second-century Athens through four lenses: past and present in the Ilissos area; the rhetoric of the Panhellenion; elite conflict and competition; and the character of the Attic countryside. My central conclusions are as follows: 1. The renewal of Athens was effected chiefly by Hadrian and the Athenian elite and was modelled on an ideal Athenian past, strategically manipulated to suit present purpose; the attractions of the fifth-century golden age for this programme of renewal meant that politically contentious history of radical democracy and aggressive imperialism had to be safely rewritten. 2. Athens and Attica retained their uniquely integrated character in the second century. Rural Attica was the subject of a powerful sacro-idyllic ideology and played a vital role in concepts of Athenian identity, while simultaneously serving as a functional landscape of production and inhabitation. 3. The true socio-economic importance of the Attic countryside as a settled and productive landscape should be investigated without unduly privileging the limited evidence from survey, and by combining all available sources, both literary and documentary, with attention to their content, cultural context and ideological relevance.
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Psychosocial factors and susceptibility to the common cold in distance runnersStruwig, Gillian Anne 30 November 2004 (has links)
This study investigated the relationship between specific psychosocial factors and susceptibility to the common cold in a sample of 124 distance runners. A cross-sectional survey design was used to assess the role of life events, coping, hardiness, training workload and competition frequency in the athlete's risk of infection. Using correlational statistical techniques, it was found that the magnitude of recent life changes and the avoidance coping strategy of denial were positively related to self-reported symptoms of the common cold. Furthermore, a significant inverse correlation was observed between hardiness and symptom duration scores. However, approach coping, training workload and competition frequency were not significantly related to the dependent measures. The results of this study suggest that certain stress-related psychosocial factors are associated with susceptibility to the common cold in distance runners. Several strategies for the prevention and treatment of upper respiratory tract infections in this group are implied by these findings. / Psychology / M.A. (Psychology)
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Newsletter für Freunde, Absolventen und Ehemalige der Technischen Universität Chemnitz 1/2008Steinebach, Mario, Thehos, Katharina 04 April 2008 (has links) (PDF)
viermal im Jahr erscheinender Newsletter für Freunde, Absolventen und Ehemalige der TU Chemnitz
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Newsletter für Freunde, Absolventen und Ehemalige der Technischen Universität Chemnitz 1/2008Steinebach, Mario, Thehos, Katharina 04 April 2008 (has links)
viermal im Jahr erscheinender Newsletter für Freunde, Absolventen und Ehemalige der TU Chemnitz
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TU-Spektrum 1/2006, Magazin der Technischen Universität ChemnitzSteinebach, Mario, Häckel-Riffler, Christine, Pollmer, Caroline, Brabandt, Antje, Mahler, Janine, Chlebusch, Michael, Doriath, Thomas, Hinkel, Rico, Kretzer, Anett 28 February 2006 (has links) (PDF)
zweimal im Jahr erscheinende Zeitschrift über aktuelle Themen der TU Chemnitz, ergänzt von Sonderheft(en)
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TU-Spektrum 1/2006, Magazin der Technischen Universität ChemnitzSteinebach, Mario, Häckel-Riffler, Christine, Pollmer, Caroline, Brabandt, Antje, Mahler, Janine, Chlebusch, Michael, Doriath, Thomas, Hinkel, Rico, Kretzer, Anett 28 February 2006 (has links)
zweimal im Jahr erscheinende Zeitschrift über aktuelle Themen der TU Chemnitz, ergänzt von Sonderheft(en)
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