The purpose of this study was to investigate the possibility to measure speed of a vehicle usingimage correlation. It was identified that a new solution of measuring the speed of a vehicle, astoday’s solution does not give the True Speed Over Ground, would open up possibilities of highprecision driving applications. It was also the intention to evaluate the performance of theproposed algorithm on a multicore platform. The study was commissioned by HalmstadUniversity.The investigation of image correlation as a method to measure speed of a vehicle was conductedby applying the proposed algorithm on a sequence of images. The result was compared toreference points in the image sequence to confirm the accuracy. The performance of the multicoreplatform was measured by counting the clock cycles it took to perform one measurement cycle ofthe algorithm.It was found out that using image correlation to measure speed has a positional accuracy of closeto a half percent. The results also revealed that one measurement cycle of the algorithm could beperformed in close to half a millisecond and the achieved parallel utilization of the multicoreplatform was close to eighty-seven percent.It was concluded that the algorithm performed well within the limit of acceptance. A conclusionabout the performance was that low execution time of a measurement cycle makes it possible toexecute the algorithm at a frequency of eighteen hundred Hertz. With a frequency that high, incombination with the camera settings proposed in the thesis, the algorithm would be able tomeasure speeds close to one thousand one hundred kilometers per hour.The authors recommend that future work should be focused on investigating the cameraparameters to be able to optimize both the memory and computational requirements of theapplication. It is also recommended to look closer at the algorithm and the possibilities ofdetecting transversal and angular changes as it would open up for other application areas,requiring more than just the speed.

Magister Scientiae - MSc / This study investigates the most important reasons behind the rst-year students' decision to select University of the Western Cape (UWC) as higher education institution. These reasons were organized into a few factors for easy interpretation. The data to be analyzed for this project is a subsection of the data collected during the orientation period of 2008. During the orientation week of 2008, the questionnaires were completed on a voluntary basis by new rst-year students. All questionnaires were anonymously completed and therefore the data does not contain any information that could be linked to any individual. For the purpose of this study, only the black African and coloured students were considered. The other racial groups were not analyzed due to too small sample sizes. Questionnaires with missing information on the reasons for selecting UWC were not nalyzed. We ended up with a sample of size 600. The data were statistically analyzed, using descriptive statistics, bivariate analyses, factor analysis, coefficient of congruence and bootstrap factor analysis. The results indicated that the most important reasons a ecting students to choose UWC were identi ed as good academic reputation, family member's advice, UWC graduates are successful and UWC graduates get good jobs. The least important reasons were found to be not accepted anywhere, parents / family members graduated from UWC, recruited by UWC and wanted to study near to home. The results also indicated that there were significant differences among students according to population groups, parent's monthly income and grade 12 average. Factor analysis of 12 variables yielded three extracted factors upon which student decisions were based. Similarities of these three factors were tested, and a high similarity among demographic characteristics and grade 12 average were found. Additional analyses were conducted to measure the accuracy of factor analyses models constructed using Spearman and Polychoric correlation matrices. The results indicated that both correlation matrices were  nbiased, with higher variance and higher loadings when the Polychoric correlation matrix was used to construct a factor analysis model for categorical data. / South Africa

Cette thèse porte sur l'étude des propriétés et l'évolution de regroupement de galaxies pour les galaxies de la gamme de 2<z<5 de VUDS Sondage, qui est la plus grande enquête de galaxie spectroscopique à z>2. Je ai pu mesurer la distribution spatiale d'une population générale de galaxie à redshift z~3 pour la première fois avec une grande précision. Je ai quantifié le regroupement de galaxie en estimation et la modélisation de la fonction de corrélation projetée (espace réel) à deux points, pour une population générale de 3022 galaxies. Je ai prolongé les mesures de regroupement à la luminosité et des sous-échantillons de masse sélectionné stellaires. Mes résultats montrent que la force de regroupement de la population générale de la galaxie ne change pas de redshift z~3,5 à z~2,5, mais dans les deux redshift va plus lumineux et des galaxies plus massives sont plus regroupées que les moins lumineux (massives). En utilisant la distribution d'occupation de halo (HOD) formalisme je mesuré une masse moyenne de halo hôte au redshift z~3 significativement plus faible que les masses halo moyens observés à faible redshift. Je ai conclu que la population de formation d'étoiles observé des galaxies à z~3 aurait évolué dans le massif et lumineux la population de galaxies au z=0. Aussi, je interpréter les mesures de regroupement en termes de biais de galaxies à grande échelle linéaire. Je trouve que ce est nettement plus élevé que le biais des galaxies redshift intermédiaire et faible. Enfin, je ai calculé le ratio-stellaire Halo masse (SHMR) et l'efficacité intégrée de formation d'étoiles (ISFE) pour étudier l'efficacité de la formation des étoiles et l'assemblage masse stellaire. / This thesis focuses on the study of the properties and evolution of galaxy clustering for galaxies in the redshift range 2<z<5 from the VIMOS Ultra Deep Survey (VUDS), which is the largest spectroscopic galaxy survey at z>2. I was able to measure the spatial distribution of a general galaxy population at redshift z~3 for the first time with a high accuracy. I quantified the galaxy clustering by estimating and modelling the projected (real-space) two-point correlation function, for a general population of 3022 galaxies. I extended the clustering measurements to the luminosity and stellar mass-selected sub-samples. My results show that the clustering strength of the general galaxy population does not change significantly from redshift z~3.5 to z~2.5, but in both redshift ranges more luminous and more massive galaxies are more clustered than less luminous (massive) ones. Using the halo occupation distribution (HOD) formalism I measured an average host halo mass at redshift z~3 significantly lower than the observed average halo masses at low redshift. I concluded that the observed star-forming population of galaxies at z~3 might have evolved into the massive and bright (Mr<-21.5) galaxy population at redshift z=0. Also, I interpret clustering measurements in terms of a linear large-scale galaxy bias. I find it to be significantly higher than the bias of intermediate and low redshift galaxies. Finally, I computed the stellar-to-halo mass ratio (SHMR) and the integrated star formation efficiency (ISFE) to study the efficiency of star formation and stellar mass assembly. I find that the integrated star formation efficiency is quite high at ~16% for the average galaxies at z~3.

Cette thèse s'intéresse aux mécanismes de déformations et d’endommagement dans les alliages de coulée pour l’industrie automobile. Les études ont porté sur un alliage modèle contenant 12% de silicium et des éléments d’addition. Il a été fabriqué par le procédé squeeze-casting (coulée sous haute pression) au LKR de l’Université Technologique de Vienne avec laquelle cette thèse s’est déroulée en collaboration. Des essais de traction in situ dans le MEB ainsi que sous tomographie aux rayons X ont permis de suivre l’évolution des microstructures pendant le chargement. Une attention particulière a été portée sur les mécanismes d’initiation et de propagation de l’endommagement. Par ailleurs la technique de la corrélation d’images numérique 2D spécialement développée pour être appliquée à des images MEB a été utilisée pour mesurer les mécanismes d’endommagement à l’échelle des inclusions. Une attention particulièreest portée sur les mécanismes de localisation de la déformation. La corrélation d’images numériques 3D appliquée aux images tomographiques a permis une mesure précise de l’évolution de l’endommagement au cours du chargement. Les données expérimentales obtenues ont permis d’adapter un modèle d’endommagement de type GTN. Une dernière étape s’est consacrée à une modélisation micro mécaniques des microstructures. Des méthodes de caractérisations basées sur des hypothèses statistiques ont permis de mesurer et d’identifier des paramètres microstructuraux. Au regard des mécanismes de déformations et de la morphologie des particules de seconde phases, des microstructures modèles sont proposées pour simuler le comportement du matériau réel. Cette démarche servant essentiellement à simplifier les modèles éléments finis afin de gagner en temps de calcul, elle sert aussi à insérer des mécanismes complexes afin de serapprocher le plus possible du comportement réel du matériau. / This thesis focuses on the mechanisms of deformation and damage in cast aluminum alloysfor automotive industry. Studies were carried on a model alloy containing 12% silicon and added element like iron and nickel. The material was prepared by squeeze-casting process at the Vienna University of Technology in Austria with which this thesis was held in collaboration. In situ tensile test with X-rays tomographic observations as well as with Scanning Electron Microscope observations were performed. They allowed following microstructure evolution under mechanical loading. Particular attention was paid to the mechanisms of initiation and propagation of damage. Furthermore the technic of Digital Image Correlation (DIC) developed to be applied to SEM images was used to visualize 2D strain localization mechanisms at second phases particles scale. DIC were also applied on tomographic images and allowed to measure accurately in 3D damage evolution under loading. Experimental data obtained from DIC were used to identify parameters of a Gurson Tvergaard Needleman model and allow to simulate by Finite Element Modeling the damage evolution. At last stages micro mechanical studies were performed by FEM using microstructure obtained from tomographic images. Algorithms were developed to measure and identify statistics parameters of the microstructure. In consideration of the mechanism of deformations and second phase particles morphology, generatedmicrostructures are proposed to simulate the behavior of the material. This approach aims to simplify the FEM models by reducing the number of degree of Freedom and, then reduce computation time. It also enables to insert complex mechanisms in the model to be as close as possible the actual behavior of the material.

The objective of this thesis is to analyse theconnection between test results and field claims of ECUs (electronic controlunits) at Scania in order to improve the acceptance criteria and evaluatesoftware testing strategies. The connection is examined through computation ofdifferent measures of dependencies such as the Pearson’s correlation, Spearman’srank correlation and Kendall’s tau. The correlations are computed from testresults in different ECU projects and considered in a predictive model based onlogistic regression. Numerical results indicate a weak connection between testresults and field claims. This is partly due to insufficient number of ECUprojects and the lack of traceability of field claims and test results. Themain conclusion confirms the present software testing strategy. Continuoussoftware release and testing results in a lower field claim and thus a betterproduct.

This study numerically examines the heat transfer and pressure drop performance of finned tube heat exchangers with staggered and inline tube layout for a range of tube pitch. The first part of the thesis considers the case where the heat exchanger is placed in fully ducted airflow. The simulations indicate that the performance reduced considerably for the staggered tube layout with an increase in the tube pitch, but a minimal difference for the inline tube arrangement. The effects of other geometrical parameters like fin pitch and the number of tube rows are then presented. Finally, a correlation for fin and tube heat exchangers with inline tube layout is proposed based on 280 simulations for 70 different configurations. The proposed heat transfer correlation can describe the database within ±8% discrepancy while the friction factor correlation can correlate the dataset within a ±10% discrepancy. The mean deviations for heat transfer and friction factor correlations are 4.3% and 5.4%. An important factor that influences the performance of flat plate and finned tube heat exchangers is when there is bypass flow around the heat exchanger. The next section of this thesis numerically investigates the partially ducted inline fin and tube heat exchanger with side bypass. The effects of the side clearance and the Reynolds number on the heat transfer and the pressure drop performance of the heat exchanger are presented. The simulations indicate that the heat transfer performance depreciates by more than 25% for infinite side clearance. The study then compares the pressure difference observed for entry, exit and the friction pressure drop with the various correlations available in the literature. Finally, the heat transfer and pressure drop performance for staggered and inline tube layouts are compared. / Thesis / Master of Applied Science (MASc)

Correlated stocks should, in equilibrium, have correlated momenta, but in practice momenta do not always correlate. We use short-term inconsistencies between correlations and momenta to predict price corrections, produce more meaningful investment indicators, and improve upon accepted investing strategies. In particular, our approaches integrate inconsistencies within an entire security class rather than relying only on individual or pairwise security data. We use this theory to improve upon not only the standard momentum portfolio but also Pair Trading and Momentum Reversion methods. This results in three strategies for portfolio allocation that outperforms overlying indices and market benchmarks by 5%-10% in annual gain with an increase of CAPM alpha over the standard momentum portfolio from -0.1 to 5.4. We expand on these strategies by showing applications generalized to comparable investing indicators including volatility.

Direct-Sequence Code Division Multiple Access (DS-CDMA), over the last few years, has become a popular technique and finds a place in many modern communication systems. The performance of this technique is closely linked to the signature (or spreading) sequences employed in the system. In the past, there have been many successful attempts by research groups to construct families of signature sequences that offer the potential gains promised by theoretical bounds. In this thesis, we present constructions of families of signature sequences over the AM-PSK and QAM alphabet with low correlation. In this thesis, we construct a family of sequences over the 8-ary AM-PSK constella- tion, Family AOpt(16) that is asymptotically optimal with respect to the Welch bound on maximum magnitude of correlation for complex sequences. The maximum magnitude of correlation for this family, θmax, is upper bounded by √N , where N is the period of the sequences. The 8-ary AM-PSK constellation is a subset of the 16-QAM constellation. We also construct two families of sequences over 16-QAM, Family A16A, and Family A16,B , with the maximum magnitude of correlation upper bounded by √2√N . We construct a family, A(M 2), of sequences over the 2m+1-ary AM-PSK constellation of period N = 2r- 1 and family size (N + 1)/2m-1 . The 2m+1-ary AM-PSK constellation is a subset of the M 2-QAM constellation with M =2m . The maximum nontrivial normalized correlation parameter is bounded above by θmax < a √N where a ranges from 1.34 in the case of M 2 = 16 to √5 for large m. Apart from low correlation values, the family possesses several interesting and useful features. In Family A(M 2), users have the ability to transmit 2m bits of data per period of the spreading sequence. The sequences in Family A(M 2) are balanced; all points from the 2m+1-ary AM-PSK constellation occur approximately equally often in sequences of long period. The Euclidean distance between the signals assigned to a particular user in A(M 2), corresponding to different data symbols, is larger than the corresponding value for the case when 2m+1-PSK modulation and spreading is used. Perhaps most interestingly, Family A(M 2) permits users on the reverse link of a CDMA system to communicate asynchronously at varying data rates by switching between different QAM constellations. Family A(M 2) is compatible with QPSK sequence families S(p) in the sense that the maximum correlation magnitude is increased only slightly if one adds sequences from (p) S(p)\ S(0) to Family A(M 2). We also construct families of sequences over AM-PSK that tradeoff data rate per sequence period and θmax for a given family size. We have extended the construction of sequences over AM-PSK constellation to construct sequences over the M 2-QAM constellation for M =2m . The QAM sequence families, Families (AM 2), have size, data rate and minimum squared Euclidean distance same as the corresponding AM-PSK construction but have higher values of θmax. Also included in the thesis are constructions for large families of sequences over the M 2-QAM alphabet.

Coefficient of Pearson r is used to compare scientific tests. In seeds technology it is used to compare results of procedures that measure vigour. When the correspondly similar results are not found in very similar conditions, Person s correlation faces criticism mainly due to two factors. The first one comes from statistics for whose usage of Person s correlation there are prescriptions that are not always observed, when they are not understood as assumption. Variables naturally associated are required with bivariated normal distribution, pairing; homoscedasticity, rectilinear dispersion; detection of outliers. Added to them, there are practical observations in what refers the correlation to be valid only in a restrict range of the data series, the necessity to create value ranges to consider this correlation as good or bad , the need of the graphical analysis, the use and interpretation of the significance, among others. The second cause of odd results would be the existence of several biological factors, which are sometimes support for the reserarcher conclusions. With the objective of identifying applicability of correlations and the causes for odd results of r, there have been compared data existent in the Seeds Analysis Laboratory of ICIAG of the Universidade Federal de Uberlândia-MG, as well as tests of germination of acelerated aging in optimal conditions of repetibility done in laboratory, and tests of field seedling emergency, as well as other simulated variables. The results showed odd results. The normal scattergram between X and Y is enough clear to elucidate only correlated variables of large samples. Although, if the covariance is not as obvious the dispersion Y=f(X) is not enough to show simultaneous increasing or decreasing between variables. With an alternative methodology of plotting the variables related to another auxiliar variable Z of the same n elements of X and Y, we could study the variable behavior in an individual way. It was possible to create graphic criteria to assess non-valid correlations, such as similarity of variables comparable to homoscedastity; influence of outliers on small or big n; grouping of outliers in a dissident range , influence of treatments effect. In the analysed cases, we concluded that, comparing seeds vigour with only laboratory results, as well as its relation with the field results and among simulated data, the results inconsistency of correlations are prevalent as they do not follow the literature prescriptions, among others. The magnitude of the distortions due to statistical causes did not leave space for measuring effects of the variation of the biological seeds conditions, temporal alterations related to management or the edafoclimatic ones. Keywords: 1. Failure in correlations 2. Correlation reliability / Coeficiente de Pearson r é usado para comparar experimentos científicos. Em tecnologias de sementes serve para comparar resultados de procedimentos que medem vigor. Quando se prognosticam resultados de correlações baseados em condições similares e eles não acontecem, a correlação de Pearson enfrenta críticas, atribuídas principalmente a duas causas. Primeiramente pela estatística, para cuja utilização da correlação de Pearson existem prescrições nem sempre observadas, talvez por não serem entendidas como pressuposições. Exigem-se variáveis métricas naturalmente associadas, com distribuição normal bivariada, pareamento, homoscedasticidade, nuvem de dispersão retilínea; detectção de outliers. Somam-se observações práticas quanto à validade restrita a um trecho da série de dados, da criação de faixas de valores para considerá-la de baixa a alta , da necessidade da análise gráfica, da interpretação de significância, entre outras. A segunda causa seria justamente a existência de variação biológica devido a fatores diversos externos e interno às sementes, servindo às vezes de sustentáculo para conclusões de interesse do pesquisador. No objetivo de identificar aplicabilidade das correlações e as causas de resultados estranhos, foram comparados dados existentes no Laboratório de Análises de Sementes do ICIAG da Universidade Federal de Uberlândia-MG, testes germinação de envelhecimento acelerado em condições ideais de repetibilidade em laboratório, e teste de emergência de plântulas em campo, e outras variáveis simuladas, havendo incidência de resultados estranhos. A representação gráfica normal da dispersão entre X e Y mostra satisfatoriamente o correlacionamento de variáveis naturalmente associadas com n grande. Entretanto, se a covariância não é tão óbvia, a disperção Y=f(X) não é suficiente para mostrar crescimento ou decréscimo simultâneo entre as variáveis. Usando metodologia alternativa de plotagem das variáveis em relação a uma variável auxiliar Z, de mesmos n elementos que X e Y, pôde-se estudar individualmente o comportamento das variáveis. O método gráfico permitiu taxar correlações em válidas ou não pela similaridade das variáveis, comparável à homoscedasticidade; verificar outliers em n pequeno ou grande; agrupamento de outliers em trecho dissidente e mostrar efeito de tratamentos. Nos casos analisados, concluiu-se que, comparando vigor de sementes com resultados só de laboratório, tão bem como no seu relacionamento com os de campo; e entre dados simulados, as inconsistências de resultados de correlações são preponderantes por não seguirem as prescrições da literatura, entre outras. A magnitude das distorções por causas estatísticas não deixou espaço para mensurar efeitos da variação de condições biológicas de sementes, alterações temporais relativas a manuseio ou edafoclimáticas. / Mestre em Agronomia

This thesis describes the development and applications of an extension of DWS which enables the recovery of ‘localized’ mechanical properties, in a specified region of a complex jelly-like object which is inhomogeneous, marked out by the focal volume of an ultrasound transducer, also called the region-of-interest (ROI). Introduction of the sinusoidal forcing creates a sinusoidal phase variation in the detected light in a DWS experiment which modulates the measured intensity autocorrelation, g2 (τ ). Decay in the modulation depth with τ is used to recover the visco-elastic spectrum of the material in the ROI. En route to this, growth of the mean-squared dis- placement (MSD) with time is extracted from the modulation depth decay, which was verified first by the usual DWS experimental data from an homogeneous object with properties matching those in the ROI of the inhomogeneous object and then those obtained by solving the generalized Langevin equation (GLE) modelling the dynamics of a typical scattering centre in the ROI. A region-specific visco-elastic spectral map was obtained by scanning the inhomogeneous object by the ultrasound focal volume. Further, the resonant modes of the vibrating ROI were measured by locating the peaks of the modulation depth variation in g2(τ ) with respect to the ultrasound frequency. These resonant modes were made use of to recover elasticity of the material of the object in the ROI. Using a similar strategy, it was also shown that flow in pipe can be detected and flow rate computed by ‘tagging’ the photons passing through the pipe with a focussed ultrasound beam. It is demonstrated, both through experiments and simulations that the ultrasound-assisted technique devel- oped is better suited to both detect and quantitatively assess flow in a background of Brownian dynamics than the usual DWS. In particular, the MSD of particles in the flow, which shows forth a super-diffusive dynamics with MSD growing following τ α with α < 2, is captured over larger intervals of τ than was possible using existing methods. On the theoretical front, the main contribution is the derivation of the GLE, with multiplicative noise modulating the interaction ‘spring constant’. The noise is derived as an average effect of the micropolar rotations suffered by the ‘bath’ particles on the ‘system’ particle modelled. It has been shown that the ‘local’ dynamics of the system particle is nontrivially influenced by the dynamics, both translation and rotation, of ‘nonlocal’ bath particles.