Adaptive streaming is a popular technique that allows quality adaption for videos based on the current playback conditions. The purpose of this thesis is to investigate how chunks in video files downloaded from YouTube correlate to each other. We investigate how the chunk size characteristics depend on the category and encoding of the video. The main focus is to analyze the chunk sizes of the video, focusing on distinctness between 360$^\circ$ and 2D videos. This is performed using the YouTube API. The videos are downloaded and analysed using youtube-dl and mkv-info. The results show that chunk sizes for adjacent qualities have higher correlation and that videos having a similarity between scenes have higher correlation. In addition, 360$^\circ$ videos differ primarily from regular 2D videos by the amount of qualities used and a generally higher correlation for all qualities.

Thulani Nyathi, Student no: 0413256X, MSc thesis, Physics, Faculty of science. 2006. Supervisor: Prof D van der Merwe. / This study aims to calculate tumour control probabilities (TCP) and normal tissue complication probabilities (NTCP) using radiobiological models and correlate these probabilities with clinically observed treatment outcome from follow-up records. These radiobiological calculations were applied retrospectively to thirty-nine paediatric patients who were treated with radiation at Johannesburg Hospital during the period January 1990 to December 2000 and had histologically proven rhabdomyosarcoma. Computer software, BIOPLAN, was used to calculate the TCP and NTCP arising from the dose distribution calculated by the treatment planning system and characterized by dosevolume histograms (DVHs). There was a weak correlation between the calculated TCP and the observed 5-year overall survival status. Furthermore, potential prognostic factors for survival were examined. Statistical analysis was performed using the Cox proportional hazards regression model. The 5-year overall survival rate was 55 %. The findings of this study are a yardstick against which more aggressive radiotherapy fractionation regimes can be compared.

A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 2017 / The period from 2006 to 2015 was a turbulent one for mining companies. The end of the 2000s commodity super cycle resulted in all-time high market values for most commodity based companies, followed by a rapid decline in value with the onset of the Global Financial Crisis in 2008 and a similar rapid recovery following this. Whilst much of this change in value was driven by commodity prices, the inconsistent performance between companies suggests that there are other factors affecting mining company value. To determine the key drivers of company value, four diversified and international mining companies which represent close to 50% of the 2006 industry revenue were selected for analysis. These were Anglo American, BHP Billiton, Rio Tinto and CVRD-Vale. Financial and production data was collected to analyse different potential value drivers. Because of its suitability for comparison of company value, the market based valuation approach was selected as the company valuation technique. Enterprise value (EV) was the metric used for company value since this provides a measure of the real market value of a firm as a whole business. Eight potential value drivers, which include production output, commodity price, revenue, EBITDA margin, EBITDA multiple, gearing ratio, net debt to EBITDA ratio and ROCE, were selected for analysis. Each potential value driver was tracked against EV to determine if there was any correlation between the value driver and EV. Also, the Pearson correlation method was used to determine correlation between each potential value driver and EV. Production output and commodity price in isolation were found not to drive company value. However, when combined to calculate revenue, had a very high correlation to EV with an average Pearson coefficient of 0.8. EBITDA multiple was also found to be a key driver of company value, with this metric closely aligned to revenue (Pearson coefficient of 0.6). The two debt metrics, gearing ratio and net debt to EBITDA were found to only have a correlation to EV in times of declining commodity prices and revenue. EBITDA margin and ROCE were found to have no correlation to EV and as such were not considered to be key drivers of company value. Mining companies must ensure that they focus on the correct value drivers to ensure those they influence do impact the company value. / MT 2017

Orientador: Carlos Roberto Padovani / Banca: Teresa Cristina Martins Dias / Banca: Sandra Fiorelli de P. Simeão / Banca: Marie Oshiiwa / Banca: Antonio Carlos Simões Pião / Resumo: A necessidade de entender o relacionamento entre variáveis biológicas faz da análise multivariada uma metodologia com grande potencial de aplicação em várias áreas do conhecimento. Na agricultura, sua utilização vem auxiliando a compreensão e a obtenção de respostas altamente interessantes e práticas, que permitem optar pelo seu emprego, tanto pela eficiência como pela acurácia do método na interpretação dos resultados. A partir da utilização de técnicas multivariadas pautadas em procedimentos quantitativos mais robustos e sensíveis, buscou-se caracterizar o perfil produtivo e climático das microrregiões do Sudeste do estado de Mato Grosso e construir modelos para quantificar e aprofundar a interrelação entre produtividade e variáveis climáticas nas respectivas regiões. Para classificar microrregiões semelhantes segundo suas características, quando nenhuma suposição foi feita concernente ao número de grupos ou a estrutura do grupo, utilizou-se a análise de agrupamento. Buscando variáveis agrícolas e de produtividade e a incorporação de novos procedimentos multivariados na interrelação desses indicadores, utilizou-se a análise de correlação canônica. Para a operacionalização desses procedimentos multivariados foram estabelecidas técnicas para estimar os componentes climáticos não disponíveis em algumas das microrregiões estudadas. A análise de agrupamento permitiu desenhar um mosaico de heterogeneidade espacial e estabelecer diferentes perfis na composição dos grupos de microrregião, reunindo as mais tradicionais no cultivo de uma espécie, ou mais produtivas, ou aquelas mais propícias ao desenvolvimento de determinada cultura. A análise fatorial estabeleceu dois eixos canônicos para as interrelações entre as culturas, sendo o primeiro fator explicando 42,22% da variância total correlacionado com as culturas anuais, podendo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The knowledge of the relationship between biological variables makes the multivariate analysis a potential tool for applications in several science fields. In agriculture, this technique has enabled the understanding and obtaining responses very real, which show the possibility of use by both the efficiency and the accuracy of the method in the interpretation of results. The purpose of this research is to use of multivariate techniques based on quantitative procedures to improve the knowledge about the climatic variables of the southeast of Mato Grosso state, which helps to solve problems in the agricultural sector. Also, the grouping analysis classified the micro regions in similar groups. The factorial analysis showed the dimensions of the variation structure of data, enabling the determination of the extent of each variable in each dimension. The smaller regions were defined from interpreting of the interrelationship between the products grown in the region. The correlation canonic analysis was used to describe the association between the number of variables and agricultural productivity. Thus, new procedures were incorporated in multivariate interrelationship of these indicators. Some climatic components, not available in a few micro regions, were estimated through multivariate techniques. Cluster analysis allowed the design of a mosaic of spatial heterogeneity regions. It established different profiles in the composition of groups, joining the more traditional in the culture of a species, or more productive, or those for the development of a particular culture. The factorial analysis established two canonical axes for the interrelationships between cultures. The first factor explaining 42.22% of total variance associated with annual crops (called "annual crops factor "). The second factor explained 16, 11% ("semi perennial crop factor")... (Complete abstract click electronic access below) / Doutor

Cette thèse de doctorat est composée de trois chapitres, un article et deux papiers et est principalement liée au domaine de l’économétrie financière empirique. Elle analyse la dépendance et le lien entre les marchés financiers et les marchés de matières premières, en particulier celui de l’énergie. Les distributions et corrélations des variables appartenant aux deux marchés sont étudiées afin de déterminer leurs effets les uns sur les autres et d’analyser leurs tendances pour donner un meilleur aperçu de leurs comportements vis-à-vis des crises et des événements brusques en économie. Ces variables sont représentées par certains indices financiers (SP500, Euro stoxx 50, Msci China) ainsi que par les principaux indices de matières premières (SP GSCI, Brent Oil,Gaz naturel, Metaux precieux). Nous choisissons de modéliser leur corrélation dans le temps et de prendre en compte la non-linéarité et l’instabilité qui peuvent les affecter. Pour cela, l’approche fonction copule a été employée pour modéliser d’une manière efficace leurs distributions. Dans le premier chapitre, nous examinons la dépendance et les co-mouvements entre les prix des émissions de dioxyde de carbone et les indices énergétiques comme le charbon, le gaz naturel, le Brent oil et l’indice énergétique global. Le deuxième chapitre analyse les interactions et relations entre le marché pétrolier et deux principaux marchés financiers en Europe et aux États-Unis représentés par l’Euro stoxx 50 et le SP500. Dans le dernier chapitre, on analyse la dépendance multivariée entre les indices de matière première de différents secteurs avec des indices financiers en utilisant le modèle de la copule Regular Vine. / This Ph.D. thesis is composed by three chapters and is mainly related to theempirical financial econometrics field. It analysis the dependence and correlationbetween the financial markets and the commodity markets specially energy.Variables from both markets are studied to determine their effects on each othersand to analyse their trends to giva a better insight to their co-movements.These variables are represented by some of the major equities (SP500, Eurostoxx 50, Msci China) as well as major commodities indices (SP GSCI commodity,Brent Oil, Natural Gas, Precious metals). We choose to model theircorrelation dynamically and take into account any non-linearity and stylisedfacts into the nature of their dependencies. For that, the copula approach wasused to model efficiently the correlated joint distributions of the studied variables.In the first paper, we examine the dependence and co-movements between theprices of the carbon dioxide emissions and energy commodities (coal, naturalgas, Brent oil and SP GSCI energy index). The dependence between thereturns was modeled by a particular class of dynamic copula, the StochasticAutoregressive Copula (SCAR). The second chapter analysis the interactions and co-movements between the oilmarket and two major stock markets in Europe and the US (the Euro stoxx 50and the SP500). Both the dynamic and the markov (regime switching) copulawere chosen to better understand the link between the two. In The last paper, I study the multivariate dependence between commoditiesfrom different sectors with some major equities using the Regular Vine copula model.

Orientador: Josineudson Augusto II Vasconcelos Silva / Coorientador: Lenira El Faro Zadra / Banca: Danísio Padro Munari / Banca: Rúsbel Raul Aspilcueta Borquis / Resumo: O desempenho medido por características de produção de leite e de eficiência reprodutiva são os principais critérios de seleção nos rebanhos leiteiros devido às consequências diretas na rentabilidade econômica do sistema. O objetivo deste trabalho foi identificar as variáveis que representem a maior parte da variação fenotípica e genética, além de estimar os parâmetros genéticos de características de produção e reprodução. Foram analisados registros de 5.217 matrizes da raça Holandesa utilizando análise de componentes principais (ACP) e análise de fatores (AF). As características avaliadas foram: produção de leite aos 305 dias de lactação (P305), produção de leite por dia de intervalo de partos (PLIEP) e pico de lactação (PICO), intervalo da data do parto ao primeiro cio (I1C), intervalo da data do parto a última cobertura (IUC), intervalo de partos (IP) e duração da gestação (DG). A estrutura de associação das características foi verificada utilizando os métodos ACP e AF para extrair novas variáveis a partir da matriz de correlação dos fenótipos por meio do software estatístico SAS®. Os resultados indicaram que ACP e AF extraíram três e quatro variáveis latentes retendo 81,5 e 88,9% da variação total dos dados, respectivamente. As características que tiveram maior participação nos componentes e fatores selecionados foram P305, PLIEP, PICO, IUC e IP. A característica DG apresentou independência frente ao conjunto de variáveis avaliadas. Parâmetros genéticos foram estimados ut... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The main causes of discard in dairy herds are the milk production and the reproductive efficiency traits due to direct consequences on economic profitability of the system. These two groups of characteristics are interconnected, occurring correlated response when selected some of them. The aim of this study was to evaluate the structure of phenotypic and genetic associations in addition to estimate genetic parameters of production and reproduction traits. Records of 5,217 Holstein cows were analyzed using principal component analysis (PCA) and factor analysis (FA). The traits studied were: 305-day accumulative milk yield (Y305), milk yield per day of calving interval (MYCI) and peak yield (PY), interval between calving and first estrus (CFE) interval between calving and last service (CLS), calving interval (CI), and gestation length (GL).The association structure of the traits was verified using the ACP and AF methods to extract new variables from the phenotypes correlation matrix using statistical software SAS®. The results indicate that ACP and AF managed to extract three and four latent variables explained 81 and 88.9% of the total variance of the dataset, respectively. The principal component analysis was more efficient than the analysis of factors, get summarize the information in fewer latent variables. Genetic parameters were estimated using six different models: standard multi-trait model and five reduced rank models fitting the first 2, 3, 4, 5 and 6 genetic principa... (Complete abstract click electronic access below) / Mestre

Orientador: Gustavo Vitti Môro / Banca: Maria Elisa Ayres Guidetti Zagatto Paterniani / Banca: Ivana Marino Bárbaro Torneli / Banca: Rinaldo César de Paula / Banca: Dilermando Perecin / Resumo: O milho-pipoca nacional apresenta baixa variabilidade genética e o desenvolvimento de linhagens avançadas e novas cultivares com alta produtividade de grãos (PG) e capacidade de expansão (CE) é dependente da determinação precisa de grupos heteróticos e do conhecimento das associações entre as principais características de importância para a cultura. O objetivo deste trabalho foi realizar análise dialélica e estimar a correlação entre as principais características em populações oriundas de linhagens S3 de milho-pipoca. Para avaliação da capacidade combinatória foram obtidos 36 híbridos e seus recíprocos, os quais foram avaliados em delineamento de blocos casualizados com 72 tratamentos e duas repetições em dois anos, sendo avaliada a PG e CE. Para avaliação da correlação entre as características foi utilizado 41 genótipos dentre os híbridos e recíprocos obtidos que foram avaliados em blocos casualizados para três amostras de 50 grãos de cada parcela de cada repetição: comprimento do grão (CG), espessura do grão (EG), largura do grão (LG), diâmetro do grão (DG) massa de 50 grãos (MG) e CE. Foram estimados a capacidade geral e especifica de combinação, o efeito recíproco e materno, o coeficiente de correlação de Pearson, foi realizada análise de trilha, modelos de regressão simples e redes bayesianas. Os efeitos não aditivos dos genes foram os mais importantes no controle genético tanto da PG como da CE, indicando situação favorável para a exploração de híbridos nos programas d... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Brazilian popcorn has low genetic variability and the development of advanced lines and new cultivars with high grain yield (GY) and expansion volume (EV) is dependent on the accurate determination of heterotic groups and knowledge of associations between the main traits. The aim of this study was apply diallel analysis and correlation coefficient among the main traits from S3 lines populations of popcorn. The 36 hybrids and its reciprocals were evaluated in a randomized complete block design (RCBD) with 72 treatments and two replications in two years and GY and EV were evaluated. At the same time, from 41 hybrids of popcorn were evaluated in a RCBD design for three samples of 50 kernel from each plot: grain length (GL), grain thickness (GT), grain width (GW) of grain diameter (GD) mass of 50 grains (MG) and EV. It was estimated the general e specific combining ability, as well as the reciprocal and maternal effect, Pearson correlation coefficient, path analysis, simple regression models and Bayesian networks. The non-additive effects of genes were the most important in the genetic control of GY and EV indicating favorable situation to produce hybrids. The reciprocal effect is mainly due to non-maternal effects. The use of synthetic populations from S3 lines can be an alternative to increase the genetic variability for GY and EV in popcorn breeding programs. It was detected negative correlation between EV and the traits, except for GD, corroborating the regression models. Path analysis indicated that MG has direct and positive effect on the EV and the negative correlation observed is mainly due to the indirect effects by GW and GT. Bayesian networks detected no direct association between the kernel size and indicated that GT is the only measure that can influence the flake size of popcorn / Doutor

Since the introduction univariate GARCH models number of available models have grown rapidly and has been extended to the multivariate area. This paper compares three different multivariate GARCH models and they are evaluated using out of sample Value at Risk of dif- ferent portfolios. Sector portfolios are used with different market capitalization. The models compared are the DCC,CCC and the GO-Garch model. The forecast horizon is 1-day, 5-day and 10-day ahead forecast of the estimated VaR limit. The DCC performs best with regards to both conditional anc unconditional violations of the VaR estimates.

A técnica de Espalhamento Dinâmico de Luz (do inglês Dynamic Light Scattering, ou DLS), também conhecida por técnica de Espectroscopia por Correlação de Fótons (do inglês Photon Correlation Spectroscopy, ou PCS), é amplamente utilizada na caraterização estrutural de sistemas coloidais, fornecendo informações importantes sobre tamanhos ca- ractersticos, tempos de correlação e efeitos de polarização no sistema. A facilidade de execução dos experimentos e praticidade das análises é uma das principais vantagens desta técnica. Especificamente para sistemas diludos compostos por partculas em solução, ela pode fornecer informações diretas sobre o raio hidrodinâmico das partculas do meio. No entanto, a obtenção desse parâmetro requer a utilização de métodos de ajuste e análise dos dados experimentais que assumem diversas caractersticas do sistema e possuem li- mitações intrnsecas devido à própria resolução do método frente presença de partculas de variados tamanhos e concentrações, polidispersões contnuas de tamanho, entre vários outros fatores. Existem casos, por exemplo, onde o mesmo conjunto experimental pode ser descrito por dois modelos diferentes. Neste projeto, é proposto um estudo sistemático das limitações dos métodos de análise frente a dados simulados e experimentais, de modo a permitir a aplicabilidade destes métodos a vários tipos de sistemas. Serão investigados casos de sistemas monodispersos e polidispersos, monomodais e multimodais, através da geração de dados simulados que mimetizem a presença desses grupos de partculas, em di- ferentes proporções e polidispersões. Como resultado, teremos indicações da precisão com que estes métodos de modelagem conseguem reproduzir os valores inseridos na simulação. Além disso, experimentos reais serão realizados utilizando amostras padrão de modo a aplicar os métodos de análise a estes dados bem como contrapor os resultados obtidos pelas simulações e pelos dados experimentais. / The Dynamic Light Scattering technique, also known as Photon Correlation Spectros- copy, is widely used for the structural characterization for colloidal systems, providing important information on characteristic length scales, correlation times and polarization effects. The relative simple experimental setup and easy-to-use modeling methods are one of the main advantages of this technique. Specifically for diluted systems of particles in solution, one can obtain direct information on the hydrodynamic for the particles in the system. However, in order to retrieve this parameter it is necessary to use modeling and analysis methods for the experimental methods which assumes intrinsic characteristics on the system and have intrinsic limitations due to the resolution of the method when particles with several sizes, concentrations, etc. In several cases, the same experimental data can be described by several different models. In this project it is proposed a systematic study on the limitations on the analysis methods upon simulated and experimental data in order to investigate the applicability of these methods for several system types. Monodisperse and polydisperse systems are investigated, either composed by one type of particles (monomo- dal) or several types of particles (multimodal). As a result, one can obtain indications on the accuracy that the modeling methods can reproduce the simulated parameters. Finally, real experiments were performed using standard samples in order to test the modeling methods and to calibrate the simulation procedures.

A realização deste estudo teve como objetivo a estimação de componentes de (co) variância e parâmetros genéticos das características: peso (PES18), perímetro escrotal (PE18), precocidade de acabamento (PREC), musculosidade (MUSC) e altura (ALT), mensuradas aos 18 meses de idade, ganho de peso da desmama ao sobreano (GP345) e idade ao primeiro parto (IPP) de bovinos Nelore, utilizando-se modelos multicaracterísticas. Foram avaliados dados de 107.332 mil bovinos criados entre os anos de 1994 e 2009 em fazendas localizadas nos estados de São Paulo, Mato Grosso do Sul e Goiás, e pertencentes ao Programa de Seleção da raça Nelore da Agropecuária CFM Ltda. Utilizaram-se três diferentes modelos: modelo multicaracterísticas padrão, modelo de componentes principais e de análise de fatores, esses dois últimos contemplando os três primeiros componentes e fatores, os quais foram comparados por critérios de informação de Akaike (AIC) e Bayesiano de Schwarz (BIC). O modelo que utilizou a técnica da análise de fatores contemplando os dois primeiros fatores (MFA2) apresentou melhor ajuste, seguido do modelo que contemplou os 3 primeiros fatores (MFA3). Estes possibilitaram estimativas próximas das realizadas pelos modelos multicaracterísticas padrão, às quais se mostraram parecidas com os valores já relatados e estimados no Brasil. / This study was objectified the estimation of (co)variance components and genetics parameters of traits: weight (W18), scrotal circumference (SC18), precocity finishing (PREC), muscularity (MUSC) and height (H), measured at 18 months of age, weight gain from weaning to yearling (WG345) and age at first calving (AFC) from Nellore cattle, using multi trait models, with analysis multi trait standard, analysis of principal components and factor analysis. Were evaluated data from 107,332 bovines, managed between the years of 1994 and 2009 in farms localized on states of São Paulo, Mato Grosso do Sul and Goias, and were participants in Nellore Selection Program from CFM Company Ltda. Was utilized three different models, multi trait model, model of principal components and factor analytic, these two last contemplating the four first principal components and factors analytics and that was compared by information criteria of Akaike (AIC) and Bayesian of Schwarz (BIC). The model that used the factor analysis technique contemplating the first two factors (MFA2) presented better adjustment, followed by the model that contemplated the first 3 factors (MFA3). These allowed close estimates to those performed by the standard multi trait models, which were similar to the values already reported and estimated in Brazil.