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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.
381

Behavioral Analysis of Volvo Cars Instrument Panel During Airbag Deployment

Nazari, Amir, Nourozi, Behrouz January 2016 (has links)
Airbags are a passive safety technology, required to function with zero failure rate. Advances in Computer Aided Engineering have allowed vehicle manufacturers to predict material and system behavior in the event of a crash. The sudden and rapid nature of a vehicle frontal crash, together with strict requirements put on safety make this a sensitive task. This thesis focuses on the front passenger airbag deployment and the instrument panel’s response. Various airbag modelling techniques are studied and presented in this document. This work is part of a larger-scale attempt to model a generic-sled that is physically representative of a real vehicle. Various component tests are to be performed in the sled environment, as opposed to a real vehicle, to save costs. Various modules are added to the sled once their behavior is verified by testing and in simulations. Software are advanced enough to identify location and magnitude of stress concentrations that develop during crash. LS-DYNA is used for explicit finite element simulations of the instrument panel (IP) in question with different airbag models. Verification has been achieved by design of experiment (DOE); with tests conducted to capture both the movements of the airbag housing and IP movements in response. These movements are broken down in various phases, facilitating implementation in the sled environment. Simplifications are made both to the computer models as well as the physical testing environment. The effects of these simplifications are quantified and discussed. Theoretical background is provided where fit while assumptions are justified wherever made. DYNAmore recommendations regarding costeffective calculations as well as result verification are followed. The obtained results show that the FE models replicate the real event with acceptable precision. The findings in this work can, by minor tweaks, be implemented on other IP models in the Volvo Cars range, leading to cost-saving solutions. This thesis provides the necessary information for sled implementations as well as future improvement suggestions. / Krockkudde är en s.k. passiv säkerhetsteknik som krävs att fungera felfritt. Framsteg inom Computer Aided Engineering har tillåtit biltillverkare att förutsäga material och systembeteende i samband med krock. Den plötsliga karaktären av krock, tillsammans med höga säkerhetskrav, gör detta till en känslig uppgift. Denna avhandling fokuserar på passagerarsidans krockkudde och instrumentbrädans (IP) respons under uppblåsning. Olika metoder för modellering av krockkuddar har studerats och presenteras i detta dokument. Arbetet är en del av en större skala försök att modellera en generisk-släde som är fysiskt representativ av en riktig bil; där olika komponent-tester skall utföras för att minska kostnader. När olika modulers beteende verifieras läggs de till släden. Denna verifiering sker genom finita element (FE) simuleringar så väl som fysiska tester. FE mjukvara är idag tillräckligt avancerad för att identifiera samt visualisera spänningskoncentrationer som uppstår i en konstruktion vid krock. LS-DYNA används i detta arbete för explicita FE simuleringar av en Volvo XC90 IP, lastad med olika krockkudde-modeller. Modell verifiering har uppnåtts genom försöksplanering (DOE); med tester utförda för att fånga rörelser av IP så väl som krockkudde-behållaren. Dessa rörelser är sedan uppdelade i olika faser för enklare genomförande i släde miljön. Förenklingar och antaganden görs både till FE modeller och fysiska testmiljön. Effekter av dessa har kvantifierats och relevant teoretisk bakgrund har inkluderats. Dokumentet innehåller även diskussion kring val av mätutrustning samt förbättringsförslag för fortsatt arbete. DYNAmore rekommendationer gällande kostnadseffektiva beräkningar och verifiering av simulerings-resultat har följts. Under arbetet visade sig att FE modellerna kan återskapa händelsen med hög noggrannhet; dessa trotts svårigheter i modellering av plast material. Möjligtvis kan man, genom mindre modifieringar, relatera slutsatserna i detta arbete till olika IP modeller i företagets produktkatalog vilket förmodligen leder till ytterligare kostnadsbesparingar. Denna avhandling ger den information som behövs för genomföranden i den generiska miljön.
382

Die Eurokrise

Preunkert, Jenny, Vobruba, Georg 29 August 2016 (has links) (PDF)
Ziel des Artikels ist, die Entwicklung der Eurokrise im Spannungsfeld von Institutionen und Handeln zu erklären. Dazu rekonstruieren wir im ersten Schritt die Krise in zwei Perspektiven, zum einen als Verkettung ökonomischer und politischer Funktionszusammenhänge, zum anderen als Arena von Verteilungskonflikten. Darauf aufbauend analysieren wir den Verlauf der Eurokrise, den wir in fünf Phasen unterteilen. Im Zentrum stehen dabei folgende Fragen: 1. Welche Akteure werden jeweils in die Problemkonstellation „Eurokrise“ hineingezogen? 2. Welche Relevanz haben die unterschiedlichen Akteure für das Funktionieren der gemeinsamen Währung und wie setzen sie diese Relevanz in den Verteilungskonflikten, die sich aus der Eurokrise ergeben, ein? Es geht also um die Entwicklung der Akteurskonstellation im Zuge der Eurokrise und um die Funktionsrelevanz dieser Akteure als Handlungsressource in den Konflikten um die Verteilung der Kosten der Krise. Im dritten Schritt der Untersuchung fassen wir unsere empirische Rekonstruktion der Eurokrise zusammen. Unser Fazit ist, dass die Eurokrise die defizitäre Institutionalisierung der gemeinsamen Währung manifest macht. Weiter gehende Regulierung, also zusätzliche Institutionenbildung steht aber vor dem schwierig auflösbaren Widerspruch zwischen funktionalen Erfordernissen und Interessen, bzw. zwischen Erwartungsstabilisierung und Interessenverfolgung.
383

Causative Factors of Crashes between a Motor Vehicle and the Amish and Old Order Mennonite Horse and Buggy

Anderson, Cory 01 May 2008 (has links)
Horse and buggy transportation is spreading as rapidly as its Amish and Old Order Mennonite users are, as are buggy crashes with motor vehicles. This study examines the primary causes of 76 reported horse and buggy crashes in Pennsylvania in 2006. The main crash types identified include a motorist rear-ending a forward-moving buggy, motorist failing to pass a buggy, buggy struck while crossing an intersection, and buggy struck while making a left turn. While causative factors varied for each crash type, major factors include the motorist or buggy driver incorrectly comprehending speed differentials, the motorist acting carelessly around the buggy, and miscommunication between the motorist and buggy driver. Within these crash types, buggy conspicuity was neither a major issue nor a possible cause in most.
384

Smrt v mediálním diskurzu: případ zmizelého letadla Malaysia Airlines / Death in the media discourse: the case of the missing Malaysia Airlines plane

Brezík, František January 2016 (has links)
The diploma thesis "Death in media discourse: the case of the missing Malaysia Airlines plane" inquires into the case of the disappeared flight MH370 from Kuala Lumpur to Beijing. The flight has been mapped in Czech press as well as online newspapers from the perspective of death based on a subjectively composed qualitative method of grounded theory and discourse analysis. In the unprecedented tragical event, death is being constructed in a specific way in the context of media discourse. Hence, the allegoric character of epistemology and constructivist paradigm plays an important role here. The theoretic reflection describes the context of the relation between media and the topic of death. The abundance of topics in media associated with death is considered a symptom of a particular demand from society. The media increase the general tolerance towards images of death and violence, thus impacting character of such displays. In the reflection of the mental background, the character of perceiving death in a secularised society is denoted as metaphorical. In the research part of the thesis, discursive patterns are introduced. From them, we may understand what values associated with death are socially important and in what way does death appear and construct itself in the media. What is important here...
385

Avaliação da mobilidade urbana com ênfase na condição da acidentalidade do usuário vulnerável / Urban mobility evaluation focused in vulnerable user accidentality condition

Silveira, Igor Machado da 15 April 2016 (has links)
Atualmente vive-se uma mudança de paradigma no planejamento dos transportes: o ser humano volta a ser o centro da tomada de decisões e o automóvel fica em segundo plano. Para que isso ocorra, são necessárias ferramentas confiáveis as quais avaliem a situação atual das cidades para que sejam traçadas metas no sentido de melhorar a vida da população. A mobilidade urbana sustentável busca a melhoria do transporte baseada no tripé social, ambiental e econômico. Esse trabalho busca avaliar a condição de segurança do usuário vulnerável (sem carenagem protetora) em relação ao usuário não vulnerável (com carenagem), buscando avaliar fatores como o modo escolhido para justificar a segurança do usuário. Apesar da mudança de paradigma, as intervenções urbanas continuam voltadas ao transporte individual, assim o usuário de transporte público de má qualidade migra para outros modos, o que causa o aumento do risco relativo do usuário vulnerável. Um dos fatores que influenciam muito para essa migração é o tempo de viagem, significativamente maior para o usuário do transporte público. / The present time is known by its change in the paradigm of the transport planning. The human being is once again the main point of the decision making and the automotive vehicles are transcending to a second plan. This demands trust tools to evaluate the real situation of the cities so that real goals to improve people\'s life get drawn. The sustainable urban mobility seeks to improve the transport based on the social, environmental and economic tripod. This essay seeks to evaluate the vulnerable user safety condition (without external protection), against the non vulnerable user (with external protection), such as estimate the choice of the user justifying its safety. Besides the change of the scenario, the urban interventions are still focused in the individual transportation kind, what means that the poor conditions of the transit makes users migrate increasing the relative risk for the vulnerable users. One factor that influences the migration is the time spent on the traveling, which is a lot longer for the user of transit.
386

Modélisation statistique de la géométrie 3D de la cage thoracique à partir d'images médicales en vue de personnaliser un modèle numérique de corps humain pour la biomécanique du choc automobile / Statistical modeling of the 3D geometry of the rib cage from medical images to personalize a numerical human body model for the biomechanics of car crash

Moreau, Baptiste 14 March 2018 (has links)
La sécurité routière est un enjeu majeur de santé publique et de protection des personnes. D'après l'organisation mondiale de la santé (OMS), près de 1,2 millions de personnes meurent chaque année dans le monde suite à des accidents de la route (2015). D’après des données accidentologiques, 36,7% des blessures graves ont pour origine des lésions au thorax (Page et collab., 2012). La biomécanique en sécurité passive a pour rôle d'améliorer notre compréhension du corps humain dans le but de construire de meilleurs outils pour évaluer le risque de blessure.Les modèles numériques d'être humain sont employés pour simuler virtuellement les conditions d'un accident. Aujourd'hui, ils sont de plus en plus utilisés par les constructeurs automobiles et équipementiers pour mieux comprendre les mécanismes lésionnels. Cependant, ils n’existent que dans certaines tailles et ne prennent alors pas en compte les variations morphologiques observées dans la population.L'imagerie médicale 3D donne accès aux géométries des différentes structures anatomiques composant le corps humain. Les hôpitaux regorgent aujourd'hui de quantités d'images 3D couvrant une très large partie de la population en termes d'âge, de corpulence et de sexe.L’objectif global de cette thèse est de modéliser statistiquement la géométrie 3D de la cage thoracique à partir d'images médicales afin de personnaliser un modèle numérique de corps humain pour simuler par éléments finis des conditions de choc automobile. Le premier objectif est d’élaborer un protocole de segmentation une base de CT-scans de manière à obtenir des données géométriques adaptées à la construction d’un modèle statistique de forme de la cage thoracique.Le deuxième objectif est de construire un modèle statistique de forme de la cage thoracique, en prenant en compte sa structure articulée.Le troisième objectif est d’utiliser le modèle statistique de la cage thoracique pour déformer un modèle numérique d’être humain, de manière à étudier l’influence de certains paramètres sur le risque de blessure. / Road safety is a major issue of public health and personal safety. According to the World Health Organization (WHO), nearly 1.2 million people die each year worldwide due to road accidents (2015). According to accident data, 36.7% of serious injuries are caused by thoracic injuries (Page et al., 2012). The aim of biomechanics in passive safety is to improve our understanding of the human body in order to build better tools for assessing the risk of injury.Numerical human body models are used to virtually simulate the conditions of an accident. Today, they are increasingly used by car manufacturers and equipment manufacturers to better understand injury mechanisms. However, they exist only in few sizes and do not take into account the morphological variations observed in the population.3D medical imaging gives access to the geometries of the different anatomical structures that make up the human body. Today, hospitals are full of 3D images covering a very large part of the population in terms of age, body size and sex.The overall objective of this thesis is to statistically model the 3D geometry of the rib cage from medical images in order to personalize a numerical human body model to simulate car crash conditions.The first objective is to develop a segmentation process based on CT-scans in order to obtain geometric data adapted to the construction of a statistical model of shape of the rib cage.The second objective is to build a statistical model of the shape of the rib cage, taking into account its articulated structure.The third objective is to use the statistical model of the rib cage to deform a numerical human body model, in order to study the influence of certain parameters on the risk of injury.
387

Avaliação da mobilidade urbana com ênfase na condição da acidentalidade do usuário vulnerável / Urban mobility evaluation focused in vulnerable user accidentality condition

Igor Machado da Silveira 15 April 2016 (has links)
Atualmente vive-se uma mudança de paradigma no planejamento dos transportes: o ser humano volta a ser o centro da tomada de decisões e o automóvel fica em segundo plano. Para que isso ocorra, são necessárias ferramentas confiáveis as quais avaliem a situação atual das cidades para que sejam traçadas metas no sentido de melhorar a vida da população. A mobilidade urbana sustentável busca a melhoria do transporte baseada no tripé social, ambiental e econômico. Esse trabalho busca avaliar a condição de segurança do usuário vulnerável (sem carenagem protetora) em relação ao usuário não vulnerável (com carenagem), buscando avaliar fatores como o modo escolhido para justificar a segurança do usuário. Apesar da mudança de paradigma, as intervenções urbanas continuam voltadas ao transporte individual, assim o usuário de transporte público de má qualidade migra para outros modos, o que causa o aumento do risco relativo do usuário vulnerável. Um dos fatores que influenciam muito para essa migração é o tempo de viagem, significativamente maior para o usuário do transporte público. / The present time is known by its change in the paradigm of the transport planning. The human being is once again the main point of the decision making and the automotive vehicles are transcending to a second plan. This demands trust tools to evaluate the real situation of the cities so that real goals to improve people\'s life get drawn. The sustainable urban mobility seeks to improve the transport based on the social, environmental and economic tripod. This essay seeks to evaluate the vulnerable user safety condition (without external protection), against the non vulnerable user (with external protection), such as estimate the choice of the user justifying its safety. Besides the change of the scenario, the urban interventions are still focused in the individual transportation kind, what means that the poor conditions of the transit makes users migrate increasing the relative risk for the vulnerable users. One factor that influences the migration is the time spent on the traveling, which is a lot longer for the user of transit.
388

Analyst forecast accuracy, dispersion, and stock returns before and during stock market crashes.

January 2008 (has links)
Wang, Xiaolei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 34-39). / Abstracts in English and Chinese. / Chapter Chapter 1. --- Introduction --- p.1 / Chapter Chapter 2. --- Identification of Stock Market Crashes --- p.5 / Chapter 2.1 --- Identification Criteria --- p.7 / Chapter 2.2 --- Identification Results --- p.8 / Chapter Chapter 3. --- Data --- p.10 / Chapter 3.1 --- Data Issue for Chapter 4 --- p.10 / Chapter 3.2 --- Data Issue for Chapter 5 --- p.12 / Chapter 3.3 --- Data Issue for Chapter 6 --- p.12 / Chapter Chapter 4. --- Examination of AFE --- p.13 / Chapter 4.1 --- Definition of AFE and MAAFE --- p.13 / Chapter 4.2 --- Examination of MAAFE --- p.14 / Chapter 4.3 --- Examination of AFE by Grouping Duration --- p.15 / Chapter Chapter 5. --- Examination of AFD --- p.18 / Chapter Chapter 6. --- Examination of the Relationship between AFD and ESR --- p.22 / Chapter 6.1 --- Portfolio Strategy - Sorting by Size and Dispersion --- p.23 / Chapter 6.2 --- Portfolio Strategy - Sorting by Size and Book to Market Ratio --- p.26 / Chapter 6.3 --- Fama-French Time Series Regression Test (Three-Factor Model) --- p.28 / Chapter 6.4 --- Fama-French Time Series Regression Test (Three-Factor Model with Dispersion on the Right Hand Side) --- p.30 / Chapter 6.5 --- Introduction of a Nonlinear Form of AFD to the Fama-French Model --- p.31 / Chapter Chapter 7. --- Conclusions --- p.32 / References --- p.34 / Appendix Table I to Table XVI --- p.40-55 / Figure I to Figure VI --- p.56-61
389

Assessing the transferability of crash prediction models for two lane highways in Brazil / Avaliação da transferabilidade de modelos de previsão de acidentes em rodovias de pista simples do Brasil

Silva, Karla Cristina Rodrigues 04 September 2017 (has links)
The present study focused on evaluating some crash prediction models for two lane highways on Brazilian conditions. Also, the transferability of models was considered, specifically by means of a comparison between Brazil, HSM and Florida. The analysis of two lane highways crash prediction models was promising when the road characteristics were well known and there was not much difference from base conditions. This conclusion was attained regarding the comparison of results for all segments, non-curved segments and curved segments, confirming that a transferred model can be used with caution. In addition, two novel models for Brazilian two-lane highways segments were estimated. The model developed showed better results for non-curved segments in the calibration/validation sample. Thus, for a general analysis purpose of non-curved segments this model is recommended. Finally, there are many factors that could not be measured by these models and reflects road safety various condition. Even so, the study of crash predict models in Brazilian context could provide a better start point in safety road analysis. / O foco desta pesquisa foi avaliar a aplicação de alguns modelos de previsão de acidentes em rodovias de pista simples de três estados brasileiros. Ainda, a transferabilidade destes modelos foi abordada, especificamente por meio de uma comparação entre características do Brasil, Florida e aquelas recomendadas pelo Highway Safety Manual. O uso dos distintos modelos se mostrou promissor para situações nas quais as características da via se mantiveram semelhantes às condições para as quais os modelos foram desenvolvidos. A avaliação foi empreendida para todos os segmentos homogêneos, separados posteriormente segundo a existência de curvas horizontais. Adicionalmente, dois novos modelos foram equacionados para a amostra brasileira. O modelo de previsão de acidentes desenvolvido apresentou melhores medidas de desempenho para segmentos sem curvas horizontais, sendo recomendável para previsão de acidentes em análises preliminares. Por fim, foi constatado que outros fatores não contemplados pelos modelos podem ter impactado as condições de segurança dos locais estudados. Ainda assim, essa pesquisa representa no contexto do Brasil um ponto de partida em análises relacionadas à segurança de rodovias de pista simples.
390

THE USE OF 3-D HIGHWAY DIFFERENTIAL GEOMETRY IN CRASH PREDICTION MODELING

Amiridis, Kiriakos 01 January 2019 (has links)
The objective of this research is to evaluate and introduce a new methodology regarding rural highway safety. Current practices rely on crash prediction models that utilize specific explanatory variables, whereas the depository of knowledge for past research is the Highway Safety Manual (HSM). Most of the prediction models in the HSM identify the effect of individual geometric elements on crash occurrence and consider their combination in a multiplicative manner, where each effect is multiplied with others to determine their combined influence. The concepts of 3-dimesnional (3-D) representation of the roadway surface have also been explored in the past aiming to model the highway structure and optimize the roadway alignment. The use of differential geometry on utilizing the 3-D roadway surface in order to understand how new metrics can be used to identify and express roadway geometric elements has been recently utilized and indicated that this may be a new approach in representing the combined effects of all geometry features into single variables. This research will further explore this potential and examine the possibility to utilize 3-D differential geometry in representing the roadway surface and utilize its associated metrics to consider the combined effect of roadway features on crashes. It is anticipated that a series of single metrics could be used that would combine horizontal and vertical alignment features and eventually predict roadway crashes in a more robust manner. It should be also noted that that the main purpose of this research is not to simply suggest predictive crash models, but to prove in a statistically concrete manner that 3-D metrics of differential geometry, e.g. Gaussian Curvature and Mean Curvature can assist in analyzing highway design and safety. Therefore, the value of this research is oriented towards the proof of concept of the link between 3-D geometry in highway design and safety. This thesis presents the steps and rationale of the procedure that is followed in order to complete the proposed research. Finally, the results of the suggested methodology are compared with the ones that would be derived from the, state-of-the-art, Interactive Highway Safety Design Model (IHSDM), which is essentially the software that is currently used and based on the findings of the HSM.

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