• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 8
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 21
  • 21
  • 10
  • 5
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 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

A study of a Scale-sized Model for Analysis of Vehicular Antennas

Hsu, Yu-ching 20 June 2008 (has links)
In this study, we establish a car model which better resembles a real car and compare with the simplified car model as a reference. When taking the circular polarization antenna into consideration, we need the refined car model in the simulation. Besides, TPMS antenna measurements are conducted and the results are compared with the simulation to verify the accuracy of our simulation. The result of the simulation shows that the signal cannot be received when TPMS antenna is mounted on the rear tires. Proper solution is suggested to alleviate this problem. Due to the limitation of the measurement environment, we consider using scale-sized car model for the measurement of the antenna radiation pattern. Also, we compare the radiation pattern in the scale-sized car model with that in the full-sized car model. For the measurement of the vehicular antenna, we find that using the scale-sized car model for the preliminary estimation of the antenna radiation pattern is feasible and practicable.
2

Assisting Parallel Parking by Binocular Vision

Huang, Jyun-Han 17 August 2012 (has links)
none
3

Modeling survival after acute myocardial infarction using accelerated failure time models and space varying regression

Yang, Aijun 27 August 2009 (has links)
Acute Myocardial Infarction (AMI), commonly known as heart attack, is a leading cause of death for adult men and women in the world. Studying mortality after AMI is therefore an important problem in epidemiology. This thesis develops statistical methodology for examining geographic patterns in mortality following AMI. Specifically, we develop parametric Accelerated Failure Time (AFT) models for censored survival data, where space-varying regression is used to investigate spatial patterns of mortality after AMI. In addition to important covariates such as age and gender, the regression models proposed here also incorporate spatial random e ects that describe the residual heterogeneity associated with di erent local health geographical units. We conduct model inference under a hierarchical Bayesian modeling framework using Markov Chain Monte Carlo algorithms for implementation. We compare an array of models and address the goodness-of- t of the parametric AFT model through simulation studies and an application to a longitudinal AMI study in Quebec. The application of our AFT model to the Quebec AMI data yields interesting ndings concerning aspects of AMI, including spatial variability. This example serves as a strong case for considering the parametric AFT model developed here as a useful tool for the analysis of spatially correlated survival data.
4

Controle Skyhook aplicado a um modelo de suspensão hidropneumatica para carretas agricolas / Skyhook control of a hydropneumatic suspension system developed for use in agricultural farm wagons

Sa, Roberto Luis de 23 February 2006 (has links)
Orientador: Pablo Siqueira Meirelles / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-07T01:26:23Z (GMT). No. of bitstreams: 1 Sa_RobertoLuisde_M.pdf: 2111156 bytes, checksum: 0673c52c0192cecc5142208203b6adfb (MD5) Previous issue date: 2006 / Resumo: Este trabalho apresenta o desenvolvimento de um sistema de controle para um modelo de suspensão hidropneumática concebido para carretas agrícolas. A partir de um modelo não­ linear de um quarto de veículo com dois graus de liberdade foram implementados dois sis­temas de controle, um ativo e outro semi-ativo, ambos baseados na estratégia de controle Skyhook. Considerando-se duas excitações, uma do tipo degrau com amplitude de 40[mm]e outra do tipo variável com amplitudes contidas numa faixa de variação de +/- 30[mm], foram realizadas simulações para três situações diferentes: Com a massa suspensa na condição de carga mínima, na condição de carga média e na condição de carga máxima. Com desempenho próximo ao obtido para o sistema ativo no quesito isolação de vibrações, quando comparado com o caso passivo, o sistema semi-ativo não apresentou deteriorações significativas no mo­ vimento da massa não-suspensa. Foi mostrado que para a aplicação considerada o sistema semi-ativo mostrou ser a melhor opção, uma vez que é mais confiável e apresenta um custo de implementação mais baixo do que um sistema ativo / Abstract: This study deals with the development of a control system suited for a Hydropneumatic Suspension System designed for use in Agricultural Devices. Using the Skyhook Control methodology, two control systems are designed for a quarter car non-linear model, an active and a semi-active one. For performance measurement, two kinds of road excitation sources are considered: a 40[mm] amplitude bump and a variable road profile with amplitude range from -30 to +30[mm]. The simulations take into account three different situations: maximum sprung mass loading, minimum sprung mass loading and medium sprung mass loading. The resulting performance of the semi-active system was almost as good as the performance achieved by the active system and much better than the performance of the passive one. Since the semi-active system is more reliable and has a smaller implementation cost than the active one, for the application concerned it resulted to be the best solution / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica
5

Návrh mechanické části pohonu zadní nápravy elektromobilu / Electric Car Rear Axle Mechanic Driveline Design

Baroš, Eduard January 2017 (has links)
The aim of the diploma thesis is the design of mechanical parts of the rear axle driveline suitable for rebuilding of a given sports car into an electric car. The introductory part briefly explains the physical principles of the drive and contains a brief summary of the current concepts of electric vehicle propulsion. Afterwards, there is a comparison and selection of a suitable concept for a given electric vehicle, determination of the basic vehicle parameters based on the calculation of the longitudinal vehicle dynamics and the gearbox calculation on the basis of which the design is solved. The next part is dedicated to the computational inspection of parts using the finite element method. The final part deals with the placement of the assembly inside the vehicle and the evaluation of the drive mechanism.
6

Vliv charakteristik tlumiče na jízdní dynamiku / Influence of Damper Characteristics on Vehicle Handling

Nguyen, Michal January 2018 (has links)
This thesis deals with the examination of damper characteristics and influence of individual parameters on vehicle handling, primarily with the use of computer program Matlab Simulink.
7

Hierarchical Gaussian Processes for Spatially Dependent Model Selection

Fry, James Thomas 18 July 2018 (has links)
In this dissertation, we develop a model selection and estimation methodology for nonstationary spatial fields. Large, spatially correlated data often cover a vast geographical area. However, local spatial regions may have different mean and covariance structures. Our methodology accomplishes three goals: (1) cluster locations into small regions with distinct, stationary models, (2) perform Bayesian model selection within each cluster, and (3) correlate the model selection and estimation in nearby clusters. We utilize the Conditional Autoregressive (CAR) model and Ising distribution to provide intra-cluster correlation on the linear effects and model inclusion indicators, while modeling inter-cluster correlation with separate Gaussian processes. We apply our model selection methodology to a dataset involving the prediction of Brook trout presence in subwatersheds across Pennsylvania. We find that our methodology outperforms the stationary spatial model and that different regions in Pennsylvania are governed by separate Gaussian process regression models. / Ph. D.
8

Advanced Numerical Approaches for Analysis of Vehicle Ride Comfort, Wheel Bearings and Steering Control

Mahala, Manoj Kumar January 2015 (has links) (PDF)
Suspension systems and wheels play a critical role in vehicle dynamics performance of a car in areas such as ride comfort and handling. Lumped parameter models (LPMs) are commonly used for assessing the performance of vehicle suspension systems. However, there is a lack of clarity with regard to the relative capabilities of different LPM configurations. A comprehensive comparative study of three most commonly used LPMs of increasing complexity has been carried out in the current work. The study reported here has yielded insights into the capabilities of the considered LPMs in predicting response time histories which may be used for assessing ride comfort. A shortcoming of available suspension system models appears to be in representation of harsh situations such as jounce movement which cause full compression of springs leading to ‘jerks’ manifested as high values of rate of change of acceleration of sprung mass riding on a wheel. In the current research work, a modified nonlinear quarter-car model is proposed to account for the contact force that results in jerk-type response. The numerical solution algorithm is validated through the simulation of an impact test on a car McPherson strut in a Drop Weight Impact Testing Tower developed in CAR Laboratory, CPDM. This is followed by a detailed comparison of HCM and QCM to examine their suitability for such analysis. For decades, wheel bearings in vehicles have been designed using simplified analytical approaches based on Hertz contact theory and test data. In the present work, a hybrid approach has been developed for assessing the load bearing capacity of a wheel ball bearing set. According to this approach, the amplitude of dynamic wheel load can be obtained from a lumped parameter analysis of a suspension system, which can then be used for detailed static finite element analysis of a wheel bearing system. The finite element modelling approach has been validated by successfully predicting the load bearing capacity of an SKF ball bearing set for an acceptable fatigue life. For the first time, using a powerful commercial explicit finite element analysis tool, a detailed dynamic analysis has been carried of a deep groove ball bearing with a rotating inner race. The analysis has led to a consistent representation of complex motions consisting of rotations and revolutions of rolling elements, and generated insights into the stresses developed in the various components such as balls and races. In conclusion, a simple yet effective fuzzy logic-based yaw control algorithm has been presented in the current research. According to this algorithm, two inputs i.e. a yaw rate error and a driver steering angle are used for generating an output in the form of an additive steering angle which potentially can aid a driver in avoiding straying from an intended path.
9

Diagnostika stavu tlumiče za jízdy vozidla / On-road Diagnostic of Vehicle Damper

Vaněk, Vojtěch January 2021 (has links)
The diploma thesis deals with the analysis of the effects of shock absorber wear on the driving dynamics of the vehicle. Furthermore, a quarter model of the car was created in the Simulink software, where a procedure for evaluating the condition of the shock absorber while driving the vehicle was created. This procedure was subsequently validated on real measured data from the Hummer H3 car.
10

Bildklassificering av bilar med hjälp av deep learning / Image Classification of Cars using Deep Learning

Lindespång, Victor January 2017 (has links)
Den här rapporten beskriver hur en bildklassificerare skapades med förmågan att via en given bild på en bil avgöra vilken bilmodell bilen är av. Klassificeringsmodellen utvecklades med hjälp av bilder som företaget CAB sparat i samband med försäkringsärenden som behandlats via deras nuvarande produkter. Inledningsvis i rapporten så beskrivs teori för maskininlärning och djupinlärning på engrundläggande nivå för att leda in läsaren på ämnesområdet som rör rapporten, och fortsätter sedan med problemspecifika metoder som var till nytta för det aktuella problemet. Rapporten tar upp metoder för hur datan bearbetats i förväg, hur träningsprocessen gick  till med de valda verktygen samt diskussion kring resultatet och vad som påverkade det – med kommentarer om vad som kan göras i framtiden för att förbättra slutprodukten. / This report describes how an image classifier was created with the ability to identify car makeand model from a given picture of a car. The classifier was developed using pictures that the company CAB had saved from insurance errands that was managed through their current products. First of all the report begins with a brief theoretical introduction to machine learning and deep learning to guide the reader in to the subject of the report, and then continues with problemspecific methods that were of good use for the project. The report brings up methods for how the data was processed before training took place, how the training process went with the chosen tools for this project and also discussion about the result and what effected it – with comments about what can be done in the future to improve the end product.

Page generated in 0.0872 seconds