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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

Contributions for parametric identification and observation of powered two-wheeler vehicles / Contributions à l’identification paramétrique et à l’observation des véhicules à deux-roues motorisés

Fouka, Majda Amina Aida 05 December 2019 (has links)
Au cours des dernières années, la mobilité routière a été marquée par la croissance considérable du trafic des Véhicules à Deux-Roues Motorisés (V2RM), qui demeurant désormais le mode de déplacement le plus dominant et convoité, notamment pour les possibilités qu'il offre d'esquiver les embouteillages de trafic. Cependant, les conducteurs de deux-roues motorisés sont considérés comme les usagers de la route les plus vulnérables. En effet, le risque d'être tué dans un accident est 29 fois plus élevé pour un cyclomoteur que pour un conducteur de voiture de tourisme. Ce problème est d'autant plus important lors du freinage d'urgence ou lors de la prise de virage. Alors que les systèmes de sécurité passifs et actifs (ABS, ESP, ceintures de sécurité, airbags, etc.) développés en faveur des véhicules de tourisme ont amplement contribué à la diminution des risques sur la route, cependant, le retard dans le développement de ces systèmes pour les motos est considérable. Malgré quelques systèmes existants, les conducteurs de motos les utilisent mal ou pas du tout. Ceci est dû à une mauvaise formation et cela ne contribue donc pas à l'amélioration de leur sécurité. Par conséquent, il n'est pas anodin que ce retard, dans le développement des systèmes d'aide à la conduite, résonne avec un retard dans le développement des outils de recherches théoriques. L'objectif principal de la thèse est de concevoir des systèmes d'assistance à la conduite, ARAS (Advanced Rider Assistance Systems), pour les V2RM pouvant alerter ces conducteurs en amont des situations de conduite dangereuses. De nombreux défis sont encore ouverts en ce qui concerne la conception des systèmes ARAS comme l'accessibilité des états dynamiques et paramètres physiques des V2RM ainsi que la synthèse des indicateurs de risques en visitant tous les points d'intérêts. Nous nous intéressons alors à proposer des techniques d'estimation, tout en réduisant le nombre de capteurs et en contournant la problématique de non-mesurabilité de certains variables. Par ailleurs, la synthèse de ces approches répondant à certaines exigences (modélisation, structure simple, précision, instrumentation) constitue un défi supplémentaire. La première partie de thèse est consacrée aux algorithmes d'identification classiques. Ces techniques sont conçues pour estimer les paramètres physiques inconnus des modèles paramétriques des V2RM. La deuxième partie concerne des observateurs basés modèles. Pour cela, un observateur à entrées inconnues (UIO) pour reconstruire la dynamique de la direction en tenant compte de la géométrie de la route, et, un observateur interconnecté (IFO) pour l'estimation de la dynamique longitudinale et latéral, ont été proposées. Ensuite, nous nous sommes penchés sur des méthodes alternatives aux approches d'identification, notamment des techniques d'estimations basées identification capable à la fois d'estimer les états et les paramètres au même temps. À cette occasion, un observateur retardé à entrées inconnues pour les systèmes avec un degré relatif arbitraire (DUIO), et, un observateur de Luenberger adaptative (LAO) pour l'estimation des raideurs pneumatiques ont été développées. Les méthodes proposées nécessitent une combinaison simple de capteurs et prennent en compte des hypothèses réalistes telles que la variation de vitesse longitudinale. Tous ces travaux ont été validés à l'aide de BikeSim et/sur des données expérimentales. En outre, ce manuscrit introduit un algorithme d’auto-calibration pour l’alignement des unités de mesure inertielle (IMU). Une telle méthode d’auto-étalonnage s’applique aux boîtiers télématiques (e-Box) installés sur des véhicules à deux roues, dont les axes des IMU sont souvent mal alignés avec le repère référentielle du véhicule. La dernière partie de cette thèse traite des indicateurs objectifs (comportement sur/sous vireur de la moto et la distance de sortie de la voie de circulation) pour la quantification du risque. / Nowadays, Powered Two-Wheeled Vehicles (PTWV) are an increasingly popular means of transport in daily urban and rural displacements, especially for the possibilities it offers to avoid traffic congestion. However, riders are considered as the most vulnerable road users. In fact, the risk of being killed in an accident is $29$ times higher for a motorcycle than for a driver of a four wheeled vehicle. Therewith, the unstable nature of the PTWV makes them more susceptible to control loss. This problem is even more complex during emergency braking or on cornering maneuvers. As matter of fact, passive and active safety systems (Anti-Lock Braking (ABS), Electronic Stability Control (ESP), seat belts, airbags) developed in favour of passenger vehicles have largely contributed to the reduction of risks on the road. However, the delay in the development of security systems for motorcycles is notable. Moreover, despite some existing systems, motorcycle riders use them badly or they don't use them at all. Therefore, it is not trivial that this delay, in the development of Advanced Rider Assistance Systems (ARAS), coming from a delay in the development of theoretical and research tools. This thesis fits into the context of designing ARAS for PTWV that can alert riders upstream of dangerous driving situations. Our work deals with observation and identification techniques to estimate the PTWV dynamic states and physical parameters. These latter are fundamental for risk quantification in ARAS design and to assess the safety of the PTWV, which are the main focus of our research work. The first part of the thesis concerns classical identification techniques to estimate physical parameters of PTWV. The second part deals with model-based observers implemented to estimate the dynamic states of the PTWV. We proposed an unknown input observer (UIO) for steering and road geometry estimation and an interconnected fuzzy observer (IFO) for both longitudinal and lateral dynamics. An alternative methods for identification algorithms are observer based identifier which provide both parameters identification and states estimation. Therefore, a Luenberger adaptive observer (LAO) to estimate lateral dynamic states and pneumatic stiffness as well as a delayed unknown inputs observer (DUIO) with an arbitrary relative degree, have been developed in this thesis. As matter of fact, all these techniques allow to estimate the vehicle dynamics while reducing the number of sensors and overcoming the problem of non-measurable states and parameters. These proposed methods require a simple combination of sensors and take into account realistic assumption like the longitudinal speed variation. Among others, this manuscript introduces a self calibration algorithm for Inertial Measurement Units (IMUs) alignment. Such a self-calibration method is used for telematic boxes (e-Boxes) installed on two-wheeled vehicles, whose IMUs’ axes are often result not to be aligned with the vehicle reference system. Finally, objective indicators are setting up to quantify riding risks. These functions were studied for ARAS purpose. To highlight the performance of these approaches, we have acquired data from high-fidelity motorcycle simulator and also with data from real motorcycles. To sum up, a comparison tables are drawn up for all the presented approaches. The results of both the numerical simulations and the performed experimentations seem to be quite promising.
2

Lateral and Posterior Dynamic Bending of the Mid-Shaft Femur: Fracture Risk Curves for the Adult Population

Kennedy, Eric Allen 11 May 2004 (has links)
The purpose of this study was to develop injury risk functions for dynamic bending of the human femur in the lateral-to-medial and posterior-to-anterior loading directions. A total of 45 experiments were performed on human cadaver femurs using a dynamic three-point drop test setup. All 45 tests resulted in mid-shaft femur fractures with comminuted wedge and oblique fractures as the most common fracture patterns. The reaction loads were used to develop the injury criteria given that they represent the inertially compensated bending strength of the femur that is more appropriate for dummy load cell application. In the lateral-to-medial bending tests the peak reaction bending moments were 352 ± 83 Nm. In the posterior-to-anterior bending tests the peak reaction bending moments were 348 ± 96 Nm. Regression analysis was used to identify significant parameters, and parametric survival analysis was used to estimate risk functions. Femur cross-sectional area, area moment of inertia (I), maximum distance to the neutral axis (c), I/c, occupant gender, and occupant mass are shown to be significant predictors of fracture tolerance, while no significant difference is shown for loading direction, bone mineral density, leg aspect and age. Risk functions are presented for femur cross-sectional area, I/c, and a combined occupant gender and mass. The risk function that utilizes the most highly correlated (R2 = 0.77) and significant (p = 0.0001) variable, cross-sectional area, predicts a 50 percent risk of femur fracture of 240 Nm, 395 Nm, and 562 Nm for equivalent cross-sectional area of the 5th percentile female, 50th percentile male, and 95th percentile male respectively. / Master of Science
3

Mechanisms to identify synergies between compliance and operational risk functions

Mazula, Wandile January 2016 (has links)
Academic literature is limited on how to coordinate the compliance and operational risk functions in organisations. The functional overlap between these two functions in financial institutions, such as banks, may result in oversight gaps or unintentional duplication. This paper describes a study on the overlap between these two functions in the second line of risk and control defence. A number of documents were analysed including relevant Basel Committee documents; South African banking legislation and regulations; integrated annual results, risk and capital reports of the four largest South African (the Big Four) banks; as well as internal operational risk and compliance documents of one of the Big Four banks. Based on this study, regulatory and practice based guidelines are proposed, which may be used to improve the efficiency of the compliance and operational risk functions in banks.
4

Mechanisms to identify synergies between compliance and operational risk functions

Mazula, Wandile January 2016 (has links)
Academic literature is limited on how to coordinate the compliance and operational risk functions in organisations. The functional overlap between these two functions in financial institutions, such as banks, may result in oversight gaps or unintentional duplication. This paper describes a study on the overlap between these two functions in the second line of risk and control defence. A number of documents were analysed including relevant Basel Committee documents; South African banking legislation and regulations; integrated annual results, risk and capital reports of the four largest South African (the Big Four) banks; as well as internal operational risk and compliance documents of one of the Big Four banks. Based on this study, regulatory and practice based guidelines are proposed, which may be used to improve the efficiency of the compliance and operational risk functions in banks.
5

The Development and Validation of a Biofidelic Synthetic Eye for the Facial and Ocular CountermeasUre Safety (FOCUS) Headform

Kennedy, Eric A. 13 September 2007 (has links)
There are over 1.9 million eye injuries per year in the United States with over 30,000 patients left blind in at least one eye as a result of trauma. Some of the most severe eye injuries can occur in automobile accidents and from sports related impacts. Eye injuries in the military environment are even more prevalent and are generally more severe than eye injuries to civilians. The rate of eye injuries has dramatically increased in warfare in recent years, rising from 2% of all casualties during World War I and World War II to over 13% of all combat injuries in Operation Desert Storm. While many of the conflict-related eye injuries are caused by shrapnel and other debris, nearly 25% of the injuries are also caused by blunt trauma from motor vehicle and helicopter crashes, falling, and direct hits from blunt objects. In order to develop safety countermeasures effective at preventing these eye injuries, as well as evaluate the eye injury potential of different impacts, it is desirable to have the capability for distinguishing between injurious and non-injurious eye impacts. Current anthropometric test device (ATD) headforms lack instrumentation and facial features to allow detailed assessment of eye or discrete facial injuries. Therefore, the purpose of this dissertation is to present the development and validation of the Facial and Ocular CountermeasUre Safety (FOCUS) headform's synthetic eye and orbit and corresponding eye injury risk criteria. / Ph. D.
6

Verfahren zur Analyse des Nutzens von Fahrerassistenzsystemen mit Hilfe stochastischer Simulationsmethoden

Neubauer, Michael 11 June 2015 (has links) (PDF)
Um die Fahrzeugsicherheit auch weiterhin zu verbessern, können Systeme der Aktiven Sicherheit ihren Beitrag leisten. Zu diesem Zweck werden u. a. Unfalldatenbanken mit precrash relevanten Parametern herangezogen, mit welchen der Systemnutzen frühzeitig auf das Unfallgeschehen analysiert wird. Aufgrund von Informationsdefiziten in der bisherigen Unfallrekonstruktion stellt das Treffen von fundierten Aussagen zur precrash Phase eine Schwierigkeit dar, wie z. B. die genaue Ausgangsgeschwindigkeit. Deshalb sind zum Teil ungesicherte Annahmen notwendig, um eine precrash Phase rekonstruieren zu können. Bisher ist in Unfalldatenbanken zu jeweils einem analysierten Unfall eine einzelne mögliche precrash Phase dokumentiert, so wie der Unfall möglicherweise ablief. Weitere mögliche Varianten der precrash Phasen, die ebenso zu selben Unfall geführt hätten bleiben unberücksichtigt. Um detaillierte Aussagen zum tatsächlichen Nutzungsgrad eines Systems in einem realen Unfall abzuleiten, wird ein automatisiertes Simulationstool vorgestellt, welches mit Hilfe stochastischer Methoden auf mögliche Varianten an precrash Phasen schließt, die zum selben realen Unfall führen. Für das Tool dienen als Eingangsgröße rekonstruierte Unfälle, die in den precrash Phasen zum Teil Informationsdefizite aufweisen. Hierbei variiert die Monte Carlo Methode, ein Zufallszahlengenerator, die unterschiedlichen Ausprägungen von ausgewählten Einflussparametern entsprechend deren Häufigkeit. Dieses Tool kompensiert somit die Informationsdefizite in precrash Phasen und baut zugleich eine synthetische Unfalldatenbank mit Varianten an precrash Phasen auf, mit dem Ziel, die Vorunfallphase statistisch repräsentativ und unabhängig von einer konkreten Rekonstruktionsvariante abzubilden. In anschließenden Simulationen jeweils mit den soeben variierten precrash Phasen werden die unterschiedlichen Auswirkungen eines vorausschauenden Systems ermittelt. Die verschiedenen Einflüsse eines Systems werden auch hier mit der Monte Carlo Methode berücksichtigt, wie z. B. die Reaktionszeit des Fahrers auf eine Warnung. Im Falle eines Systemeingriffes ist eine mögliche Veränderung der Unfallschwere bzw. wahrscheinlichen Verletzungsschwere zu betrachten. Mit dieser vorgestellten Methodik ist der tatsächliche Nutzen eines vorausschauenden Systems für die Unfallbeteiligten noch genauer feststellbar, da das Simulationstool ein breites mögliches Spektrum an precrash Phasen und Systemauswirkungen betrachtet.
7

Genetic factors associated with coronary heart disease and analysis of their predictive capacity

Lluís Ganella, Carla, 1984- 26 June 2012 (has links)
The main expansion of the discovery of genetic variants associated with complex diseases has occurred during the last decade. This expansion has been accompanied, and in some sense motivated, by the desire to use this information to improve the predictive capacity of many diseases with an unidentified familial component, including coronary heart disease (CHD), with the aim of translating this genetic knowledge into clinical practice. This doctoral thesis is structured in two lines of investigation that address distinct aspects of this issue, first to evaluate the possible role of genetic variation in a candidate gene in modulating CHD risk, and second to evaluate whether genetic information can be used to improve risk assessment tools used in clinical practice. In the first research line (described in Part I), we investigate the contribution of genetic variation in one of the most widely-studied genes in cardiovascular genetics, ESR1, which encodes the Oestrogen receptor α protein. We provide a solid meta-analysis of evidence regarding the most widely-studied variant in this gene and we further explore the role of a broad range of common and uncommon variants in this gene in CHD risk. Using these approaches, we find no evidence of association between the genetic variants studied and CHD risk. However, although we can confidently accept that common genetic polymorphisms are not associated with cardiovascular disease, we cannot discard the possibility that other types of variation in this gene (for instance epigenetic variation) could modify susceptibility to cardiovascular disease, or that other elements of this pathway are associated with an increased risk of CHD. In this research I have provided a reliable answer to this long running unanswered question in cardiovascular genetics, allowing research to re-focus on other elements of this system or other pathways. In the second line, we explored the possible utility of genetic information obtained from genome-wide association studies (GWAS) in prediction of 10-year risk of CHD events by adding this information to cardiovascular risk functions. We have followed the recommendations proposed by the American Heart Association for evaluating the utility of novel biomarkers in clinical practice, and have demonstrated that although the magnitudes of the effects of these genetic variants on CHD risk are modest, there is a tendency towards improvement in the capacity of the risk functions to predict future CHD events. The translation of genetic information into clinical practice was one of the main motivations for the investment in genome-wide association studies, and my research represents one of the first efforts to explore this possibility. / L’expansió principal pel que fa al descobriment de variants genètiques associades amb malalties complexes s’ha dut a terme durant la última dècada. Aquesta expansió ha estat acompanyada, i d’alguna forma motivada, pel desig d’usar aquesta informació per millorar la capacitat de predicció d’aquelles malalties on hi és present un cert component familiar però en les que no es coneixien les variants que conferien un major risc de patir la malaltia, entre elles la cardiopatia isquèmica (CI). La present tesis doctoral està estructurada en dues línies d’investigació que avaluen el possible rol d’un gen candidat en la susceptibilitat de la CI i també avalua la millora en la capacitat de predicció d’un esdeveniment coronari de les eines usades habitualment en la pràctica clínica mitjançant la inclusió d’informació genètica. Més concretament, la primera línea d’investigació es centra en la contribució de la variació genètica en un dels gens més estudiats en relació amb CI: el gen que codifica pel receptor d’estrogens alfa (ESR1). En aquesta línea hem proveït un sòlid meta-anàlisis entre la variant més àmpliament estudiada d’aquest gen i risc coronari i també hem explorat el paper de la majoria de les variants comunes descrites en aquest gen i risc de CI. Mitjançant cap dels anàlisis hem trobat evidència d’associació entre les variants genètiques en aquest gen i el risc de CI. No obstant això, i encara que podem acceptar que les variants genètiques comunes d’aquest gen no estan associades amb esdeveniments coronaris, no podem descartar que altres tipus de variació en aquest gen (com per exemple variació epigenètica) pugui estar modificant la susceptibilitat a patir un esdeveniment coronari, ni tampoc que altres elements de la mateixa cadena de senyalització estiguin associats amb la malaltia. En la segona línea d’investigació, hem explorat el possible paper de les variants genètiques, obtingudes mitjançant estudis d’associació global del genoma (GWAS), en la millora de la capacitat de predicció a 10 anys dels esdeveniments coronaris, mitjançant la seva addició en les funcions de risc cardiovascular clàssiques. Hem seguit les recomanacions proposades per la American Heart Association per l’avaluació en la pràctica clínica de nous biomarcadors, i hem demostrat que, tot i que la magnitud de l’associació d’aquestes variants és modesta, hi ha una tendència cap a la millora de la capacitat de predicció de les funcions de risc.
8

A Risk Based Approach to Module Tolerance Specification

Shahtaheri, Yasaman 22 April 2014 (has links)
This research investigates tolerance strategies for modular systems on a project specific basis. The objective of the proposed research is to form a guideline for optimizing the construction costs/risks with the aim of developing an optimal design of resilient modular systems. The procedures for achieving the research objective included: (a) development of 3D structural analysis models of the modules, (b) strength/stability investigation of the structure, (c) developing the fabrication cost function, (e) checking elastic and inelastic distortion, and (f) constructing the site-fit risk functions. The total site-fit risk function minimizes the cost/risk associated with fabrication, transportation; alignment, rework, and safety, while maximizing stiffness in terms of story drift values for site re-alignment and fitting alternatives. The fabrication cost function was developed by collecting 61 data points for the investigated module chassis using the SAP2000 software while reducing the initial section sizes, in addition to the fabrication costs at each step (61 steps). With the reduction of the structural reinforcement, story drift values increase, therefore there will be a larger distortion in the module. This generic module design procedure models a trade-off between the amount of reinforcement and expected need for significant field alterations. Structural design software packages such as SAP2000, AutoCAD, and Autodesk were used in order to model and test the module chassis. This research hypothesizes that the influential factors in the site-fit risk functions are respectively: fabrication, transportation, alignment, safety, and rework costs/risks. In addition, the site-fit risk function provides a theoretical range of possible solutions for the construction industry. The maximum allowable modular out-of-tolerance value, which requires the minimum amount of cost with respect to the defined function, can be configured using this methodology. This research concludes that over-reinforced or lightly-reinforced designs are not the best solution for mitigating risks, and reducing costs. For this reason the site-fit risk function will provide a range of pareto-optimal building solutions with respect to the fabrication, transportation, safety, alignment, and rework costs/risks.
9

Verfahren zur Analyse des Nutzens von Fahrerassistenzsystemen mit Hilfe stochastischer Simulationsmethoden

Neubauer, Michael 24 April 2015 (has links)
Um die Fahrzeugsicherheit auch weiterhin zu verbessern, können Systeme der Aktiven Sicherheit ihren Beitrag leisten. Zu diesem Zweck werden u. a. Unfalldatenbanken mit precrash relevanten Parametern herangezogen, mit welchen der Systemnutzen frühzeitig auf das Unfallgeschehen analysiert wird. Aufgrund von Informationsdefiziten in der bisherigen Unfallrekonstruktion stellt das Treffen von fundierten Aussagen zur precrash Phase eine Schwierigkeit dar, wie z. B. die genaue Ausgangsgeschwindigkeit. Deshalb sind zum Teil ungesicherte Annahmen notwendig, um eine precrash Phase rekonstruieren zu können. Bisher ist in Unfalldatenbanken zu jeweils einem analysierten Unfall eine einzelne mögliche precrash Phase dokumentiert, so wie der Unfall möglicherweise ablief. Weitere mögliche Varianten der precrash Phasen, die ebenso zu selben Unfall geführt hätten bleiben unberücksichtigt. Um detaillierte Aussagen zum tatsächlichen Nutzungsgrad eines Systems in einem realen Unfall abzuleiten, wird ein automatisiertes Simulationstool vorgestellt, welches mit Hilfe stochastischer Methoden auf mögliche Varianten an precrash Phasen schließt, die zum selben realen Unfall führen. Für das Tool dienen als Eingangsgröße rekonstruierte Unfälle, die in den precrash Phasen zum Teil Informationsdefizite aufweisen. Hierbei variiert die Monte Carlo Methode, ein Zufallszahlengenerator, die unterschiedlichen Ausprägungen von ausgewählten Einflussparametern entsprechend deren Häufigkeit. Dieses Tool kompensiert somit die Informationsdefizite in precrash Phasen und baut zugleich eine synthetische Unfalldatenbank mit Varianten an precrash Phasen auf, mit dem Ziel, die Vorunfallphase statistisch repräsentativ und unabhängig von einer konkreten Rekonstruktionsvariante abzubilden. In anschließenden Simulationen jeweils mit den soeben variierten precrash Phasen werden die unterschiedlichen Auswirkungen eines vorausschauenden Systems ermittelt. Die verschiedenen Einflüsse eines Systems werden auch hier mit der Monte Carlo Methode berücksichtigt, wie z. B. die Reaktionszeit des Fahrers auf eine Warnung. Im Falle eines Systemeingriffes ist eine mögliche Veränderung der Unfallschwere bzw. wahrscheinlichen Verletzungsschwere zu betrachten. Mit dieser vorgestellten Methodik ist der tatsächliche Nutzen eines vorausschauenden Systems für die Unfallbeteiligten noch genauer feststellbar, da das Simulationstool ein breites mögliches Spektrum an precrash Phasen und Systemauswirkungen betrachtet.

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