Made available in DSpace on 2014-07-29T15:08:19Z (GMT). No. of bitstreams: 1 dissertacao RamonCampos UFG 2012.pdf: 5667385 bytes, checksum: 1ff8645bd9d1b27aa406264298e405ef (MD5) Previous issue date: 2012-07-09 / This study aimed to development of a computational tool for electromyographic signal (EMG) analysis by signal processing techniques to determine muscular fatigue. With Ethics Committee of Federal University of Goiás approve were recorded from the dominant biceps brachii of 10 volunteers, that did not ever had muscular disease. The protocol consisted on get the maximal voluntary isometric contraction (MVIC) from the volunteer seated, floor contact with the feet, and forearm in 90 degree, doing three maximal voluntary contraction against a rigid and fixed surface, by five seconds, with a five resting minutes between each acquisition. The MVIC values were obtained by arithmetical mean from the three greater values of each contraction. In statistical analysis the volunteer sustained a load of 60% MVIC for 30 seconds, or while they supported. For dynamical analysis was used a electrogoniometer tied in forearm to measure the angle and a 60% MVIC load for 30 seconds measured, achieved angle of 70° until 130°, and return to 70°. Each flexion was did in 1,5 seconds, or while volunteer support. To analyze the signal in time domain were used Root main square (RMS) values and Continuous wavelet transform (CWT). To analyze in frequency domain were adopted the values of mean and median from Fast Fourier Transform (FFT), Welch spectral estimator, auto regressive moving average (ARMA) filter, and analytic wavelet transform (AWT). Linear regressions were obtained using a window of 250 ms for all techniques. Slopes with positive values, in time domain, and slopes with negative values, in frequency domain, indicate muscular fatigue. Using high scales of wavelet transform shows great results while compared with default techniques, like RMS and FFT. ANOVA one way were adopted as statistical method of analysis, with P < 0,05. Only in dynamic contraction, on frequency domain, had P value < 0,05. Tukey test were applied to identify which techniques had variance great than 5%. Is suggested as future works development of a wireless system to acquire EMG signals, improvement in the software to motor unit action potentials (MUAP) detection, prosthesis control, and synchronization with others systems of data collection. / Este trabalho propõe o desenvolvimento de uma ferramenta computacional para realizar a análise do sinal eletromiográfico (EMG) por meio de técnicas de processamento de sinais a fim de detectar fadiga muscular. Com aprovação do Comitê de Ética da Universidade Federal de Goiás, foram captados os sinais eletromiográfico do bíceps braquial do braço dominante de 10 voluntários, que não apresentavam histórico de problemas musculares. O protocolo consistiu na obtenção do valor de contração isométrica voluntária máxima (CIVM) com o voluntário sentado, pés em contato com o chão e o antebraço em ângulo de 90° em relação ao tronco, realizando três repetições de contração máxima, contra uma superfície fixa e rígida, durante 5 segundos, intercaladas por um período de 5 minutos em repouso. O valor da CIVM, representando 100% da força máxima exercida, foi determinado por meio da média aritmética dos maiores valores de cada amostra. Para análise de contração estática, o voluntário realizou uma nova contração com carga de 60% da CIVM durante 30 segundos, ou até onde suportasse. Na análise de contração dinâmica, foi utilizado um eletrogoniômetro para medição do ângulo do antebraço que, ao carregar uma carga com 60% da CIVM, realizou manobra de flexão, alcançando ângulo de 70°, e manobra de extensão, atingindo ângulo de 130° do antebraço em relação ao tronco. Cada manobra (flexão e extensão) foi realizada em 1,5 segundos, durante um período de 30 segundos ou enquanto suportasse, totalizando no máximo de 10 flexões e 10 extensões. Foram adotadas para análise do sinal EMG no domínio do tempo as técnicas de cálculo do valor quadrático médio (RMS) e transformada wavelet contínua (TWC). Para análise no domínio da frequência foram adotados os valores médios e medianos obtidos pelas técnicas de transformada rápida de Fourier (FFT), o estimador espectral de Welch, o filtro autorregressivo de média móvel (ARMA) e as transformadas wavelets analíticas (TWA). Utilizando uma janela de 250 ms foram obtidos os gráficos contendo a regressão linear de todas as técnicas. A inclinação positiva da reta de regressão, para o domínio do tempo, e inclinação negativa, para o domínio da frequência, indica o processo de fadiga muscular. A utilização da transformada wavelet, em grandes escalas, apresenta valor mais significativo de indícios de fadiga muscular quando comparada às técnicas padrões RMS e FFT. O método estatístico utilizado foi a ANOVA de um fator, com o P < 0,05. Apenas na contração dinâmica no domínio da frequência obteve um P < 0,05. Aplicada a análise post hoc do teste de Tukey foram identificadas, das técnicas comparadas duas a duas, quais apresentaram um grau de variância maior que 5%. Ainda no trabalho é sugerido o desenvolvimento de equipamento de coleta de sinais EMG sem fio, o aperfeiçoamento da ferramenta desenvolvida para detecção de potenciais de ativação de unidade motora (MUAP), o controle de próteses de reabilitação, e a sincronização com outros sistemas de coleta de dados.

Na tentativa de contornar os problemas ainda existentes para a detecção e identificação de erros grosseiros (EGs) no processo de estimação de estado em sistemas elétricos de potência (EESEP), realiza-se, neste trabalho, uma análise da formulação dos estimadores aplicados a sistemas elétricos de potência, em especial, o de mínimos quadrados ponderados, tendo em vista evidenciar as limitações dos mesmos para o tratamento de EGs. Em razão da dificuldade de detectar EGs em medidas pontos de alavancamento, foram também analisadas as metodologias desenvolvidas para identificação de medidas pontos de alavancamento. Através da formulação do processo de EESEP como um problema de álgebra linear, demonstra-se o porquê da impossibilidade de detectar EGs em determinadas medidas redundantes, sendo proposto, na seqüência, um método para identificação de medidas pontos de alavancamento. Para reduzir os efeitos maléficos dessas medidas no processo de EESEP verifica-se a possibilidade de aplicar outras técnicas estatísticas para o processamento de EGs, bem como técnicas para obtenção de uma matriz de ponderação adequada. / To overcome the problems still existent for gross errors (GEs) detection and identification in the process of power system state estimation (PSSE), the formulations of the estimators applied to power systems are analyzed, specially, the formulation of the weighted squares estimator. These analyses were performed to show the limitations of these estimators for GEs processing. As leverage points (LP) represent a problem for GEs processing, methodologies for LP identification were also verified. By means of the linear formulation of the PSSE process, the reason for the impossibility of GEs detection in some redundant measurements is shown and a method for LP identification is proposed. To minimize the bad effects of the LP to the PSSE process, the possibility of applying other statistic techniques for GEs processing, as well as techniques to estimate an weighting matrix are also analyzed.

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-04-10T15:11:39Z No. of bitstreams: 1 gracilianomarciosantoslouredo.pdf: 1813142 bytes, checksum: b79d02006212c4f63d6836c9a417d4bc (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-04-11T15:25:36Z (GMT) No. of bitstreams: 1 gracilianomarciosantoslouredo.pdf: 1813142 bytes, checksum: b79d02006212c4f63d6836c9a417d4bc (MD5) / Made available in DSpace on 2018-04-11T15:25:36Z (GMT). No. of bitstreams: 1 gracilianomarciosantoslouredo.pdf: 1813142 bytes, checksum: b79d02006212c4f63d6836c9a417d4bc (MD5) Previous issue date: 2018-02-26 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / O objetivo deste trabalho é apresentar algumas contribuições para a melhoria do processo de estimação por máxima verossimilhança via algoritmo EM em modelos misturas assimétricas com regressão, além de realizar neles a análise de influência local e global. Essas contribuições, em geral de natureza computacional, visam à resolução de problemas comuns na modelagem estatística de maneira mais eficiente. Dentre elas está a substituição de métodos utilizados nas versões dos algoritmos GEM por outras que reduzem o problema aproximadamente a um algoritmo EM clássico nos principais exemplos das distribuições misturas de escala assimétricas de normais. Após a execução do processo de estimação, discutiremos ainda as principais técnicas existentes para o diagnóstico de pontos influentes com as adaptações necessárias aos modelos em foco. Desejamos com tal abordagem acrescentar ao tratamento dessa classe de modelos estatísticos a análise de regressão nas distribuições mais recentes na literatura. Também esperamos abrir caminho para o uso de técnicas similares em outras classes de modelos. / The objective of this work is to present some contributions to improvement the process of maximum likelihood estimation via the EM algorithm in skew mixtures models with regression, as well as to execute in them the global and local influence analysis. These contributions, usually with computational nature, aim to solving common problems in statistical modeling more efficiently. Among them is the replacement of used methods in the versions of the GEM algorithm by other techniques that reduce the problem approximately to a classic EM algorithm in the main examples of skew scale mixtures of normals distributions. After performing the estimation process, we will also discuss the main existing techniques for the diagnosis of influential points with the necessaries adaptations to the models in focus. We wish with this approach to add for the treatment of this statistical model class the regression analysis in the most recent distributions in the literature. We too hope to paving the way for use of similar techniques in other models classes.

Depuis les années 90, la technologie réseau et radio mobile a fait l'objet de progrès phénoménaux. Cette avancée technologique s'est faite en parallèle du côté réseau, du côté application et du coté besoin de l’utilisateur. L’évolution rapide de la technologie a eu pour conséquence l’existence d’un environnement hétérogène où la couverture est assurée par la coexistence de plusieurs types de réseaux. Le défi soulevé par cette architecture est de pouvoir naviguer entre plusieurs réseaux d’une façon transparente. La navigation entre réseaux de types différents est connue sous le nom du Handover vertical. Le standard IEEE 802.21 offre une composante appelée Media Independent Handover (MIH) qui contient une fonction capable de transmettre l’état des liens du nœud mobile depuis les couches inférieures vers les couches supérieures. MIH s’intercale entre le niveau 2 et le niveau 3 dans la pile protocolaire. Le rôle principal de MIH est d’aider le nœud mobile à faire un transfert sans coupure entre des réseaux de types différents, mais la logique de sélection est laissée sans implémentation.Dans ce contexte nous avons travaillé sur l’amélioration de la gestion du Handover en proposant une nouvelle architecture appelée VHMC et basée sur MIH offrant des nouvelles méthodes de sélection du réseau destination. La première proposition est un nouvel algorithme nommé Multiple Criteria Selection Algorithm (MCSA) basé sur plusieurs paramètres de qualité du service. Nous avons utilisé le simulateur Network Simulator (NS2) pour évaluer nos propositions en étudiant le nombre de paquets perdus et le temps de latence du Handover durant la période du transfert. La deuxième contribution est un nouveau modèle de sélection du réseau destination basé sur la technique de la logique floue. La base d’inférence, qui est l’élément central de la décision de ce modèle, est déduit grâce à une étude basée sur un nombre élevé de cas de Handover réels collectés des serveurs de la compagnie de télécommunication libanaise "Alfa". Une troisième solution est proposée à travers un nouveau modèle de sélection du réseau destination basé sur la théorie de la régression linéaire multiple. / Since 1990, networking and mobile technologies have made a phenomenal unprecedented progress. This progress has been experienced on multiple fronts in parallel; especially on the application level and the user's needs one. This rapid evolution of the technology imposed a need for the existence of heterogeneous environments where the coverage is ensured throughout the different available networks. The challenge with such architecture would be to provide the user with the ability to navigate through the different available networks in a transparent and seamless fashion. However, the navigation among different types of networks is commonly referred to as vertical Handover. The IEEE 802.21 standard offers a component that is called Media Independent Handover (MIH) which has a function that provides the capability of transmitting the state of the connection of the mobile nodes from the lower to upper layers. This layer would exist between layer 2 and layer 3 within the protocol architecture. The main role of MIH is to help the mobile node transfer without interrupt among different types of networks, but the logic of selection is left without implementation. In this context, we worked on the improvement of the Handover management by proposing a new architecture, called VHMC and based on MIH by offering new methods for selecting the destination network. The first solution is a new algorithm called Multiple Criteria Selection Algorithm (MCSA) based on multiple parameters of the quality of service. We used Network Simulator (NS2) for testing our approach and study the number of lost packets and lost time during Handover. The second solution is a new model for selecting the destination network based on fuzzy logic techniques. The distinctive characteristic of this model lies in the study of genuine Handover records taken from a Lebanese mobile operator called "Alfa". A third proposed solution for network selection is based on multiple linear regression theory.

M.Comm. (Financial Management) / There is a wide perception that bank net interest margins (NIMs) in Sub-Saharan Africa in general and South Africa in particular, are higher compared to other regions. The study investigates four commercial banks in South Africa with the aim of identifying the relevant factors affecting the behaviour of NIMs in commercial banking in South Africa, and draws comparisons with other markets. The study employs the Classical Linear Regression Model (CLRM) using the Ordinary Least Squares (OLS) data estimating technique to analyse net interest margins over the period 2000 to 2010. The study takes note of Ho and Saunders’s seminal work produced in 1981, and subsequent extensions and modification by other authors and researchers. Net interest margins are modeled in a single-step together with explanatory variables driven from the theoretical model. Using data obtained from the Bankscope data base, the variables examined in the study are; competitive structure of the market, average operating costs, management’s propensity for risk aversion, credit risk exposure, the quantum of the bank’s operations, short-term money market interest rate volatility, the opportunity cost of holding reserves and quality of management running the institution. The findings of the study suggest that market power, average operating costs, degree of risk aversion, credit risk exposure, and size of operations are major factors explaining the behaviour of NIMs in South Africa. These variables are major in terms of the number of banks that exhibit statistical significance. Market power, interest rate volatility and opportunity cost of holding reserves are also relevant factors, although they affect fewer banks than the major factors. Comparison of South African net interest margins determinants with those from other regions reveals some fundamental differences. These differences indicate that banks from different countries and regions are faced with different operating environments and risk profiles that drive net interest margins.

Understanding the functional impact of physical interactions between proteins and DNA on gene expression is important for developing approaches to correct disease-associated gene dysregulation. I conducted a systematic, functional genetic analysis of protein-DNA interactions in the promoter region of the yeast ribonucleotide reductase subunit gene RNR3. I measured the transcriptional impact of systematically perturbing the major transcriptional regulator, Crt1, and three X-box sites on the DNA known to physically bind Crt1. This analysis revealed interactions between two of the three X-boxes in the presence of Crt1, and unexpectedly, a significant functional role of the X-boxes in the absence of Crt1. Further analysis revealed Crt1- independent regulators of RNR3 that were impacted by X-box perturbation. Taken together, these results support the notion that higher-order X-box-mediated interactions are important for RNR3 transcription, and that the X-boxes have unexpected roles in the regulation of RNR3 transcription that extend beyond their interaction with Crt1.

Lake volume and lake depth are important variables that defines a lake and its ecosystem. Sweden has around 100 000 lakes, but only around 8000 lakes has measured data for volume, max- and mean-depth. To collect data for the rest of the lakes is presently too time consuming and expensive, therefore a predictive method is needed. Previous studies by Sobek et al. (2011) have found a model predicting lake volume from map-derived parameters with high degrees of explanation for mean volume of 15 lakes or more. However, the predictions for one individual lake, as well as max- and mean-depth, were not accurate enough. The purpose with this study was to derive better models based on new map material with higher resolution. Variables used was derived using GIS-based calculations and then analyzed with multivariate statistical analysis with PCA, PLS-regression and multiple linear regression. A model predicting lake volume for one individual lake with better accuracy than previous studies was found. The variables best explaining the variations in lake volume was lake area and the median slope of an individual zone around each lake (R2=0.87, p&lt;0.00001). Also, the model predicting max-depth from lake area, median slope of an individual zone around each lake and height differences in the closest area surrounding each lake, had higher degrees of explanation than in previous studies (R2=0.42). The mean-depth had no significant correlation with map-derived parameters, but showed strong correlation with max-depth. Reference Sobek, S., Nisell, J. &amp; Fölster J. (2011). Predicting the volume and depths of lakes from map-derived parameters. Inland Waters, vol. 1, ss. 177-184.

This research analyses the statistical relationship between income distribution and seven taxation and government expenditure components in Namibia using data from 1996-2016. The research is aimed at creating new knowledge on the research topic because no literature exists for Namibia. The Autoregressive Distributed Lag (ARDL) cointegration technique was employed to assess the long-run relationship between the dependent and independent variables in Eviews. The research findings indicated that there is no long-run relationship between the dependent variable and independent variables. In the short-run, the research findings indicate that government expenditure on social pensions and government expenditure on education have a balancing effect on income distribution, while tax on products, corporate income tax and customs and excise duties have an unbalancing and/or worsening effect on income distribution. Based on these findings, tertiary education loans are recommended as opposed to grants to ensure sustainability of Namibia Students Financial Assistance Fund (NASFAF). In adjusting corporate and value added taxes, the government is cautioned to avoid overburdening consumers and employees through tax shifting in the form of high prices of goods and services and low wages and benefits. A tax mix, tax discrimination and a hybrid of taxation and government expenditure components are strongly recommended to achieve a balance. / Economics / M. Com. (Economics)

No description available.

La presente investigación está relacionada principalmente con la utilización del Ensayo de Penetración Estándar (SPT) y el Ensayo de Corte Directo, a través de dichos ensayos se obtuvo resultados que se usaron para formular una expresión de corrección. El estudio se realizó en suelos arenosos que poseen un porcentaje de finos menor al 12 % en los distritos limeños de Villa El Salvador y Ventanilla. Debido a la gran difusión y utilización del Ensayo de Corte Directo es de suma importancia que los resultados obtenidos sean lo más confiable posible, pues de ello depende el diseño de estructuras de cimentación, taludes, terraplenes, entre otros. Sin embargo, existe una gran dificultad para obtener muestras inalteradas de suelos arenosos, lo que induce a que se realice ensayos de Corte Directo remoldeando el espécimen a su densidad natural, contenido de humedad, compacidad y demás, esto podría generar una variación considerable en los resultados (parámetros de resistencia del suelo). En base a lo descrito anteriormente, se considera necesario buscar la manera de contrarrestar dicho problema, por ello se propone formular una expresión de corrección para el ángulo de fricción obtenido en los ensayos de Corte Directo de muestras remoldeadas. Para la formulación de dicha expresión, se empleó el programa Microsoft Excel para realizar una regresión lineal múltiple con las variables relacionadas al ángulo de fricción teniendo como resultado una expresión de corrección que mejora los ángulos de fricción del Ensayo de Corte Directo en un 63.69 %. / The present investigation is mainly related to the use of the Standard Penetration Test (SPT) and the Direct Shear Test, through these tests results were obtained that were used to formulate a correction expression. The study was carried out on sandly soils with a percentage of fine less than 12 % in the Lima districts of Villa El Salvador and Ventanilla. Due to the great diffusion and use of the Direct Shear Test it is of utmost importance that the results obtained are as reliable as possible, since it depends on the design of foundation structures, slopes, embankments, among others. However, there is great difficulty in obtaining undisturbed samples from sandy soils, which induces to Direct Shear tests being carried out, reshaping the specimen to its natural density, moisture content, compactness and others, this could generate a considerable variation in the results (soil resistance parameters). Based on the above, it is considered necessary to find a way to counteract this problem, for this reason it is proposed to formulate a correction expression for the friction angle obtained in the Direct Shear tests of remoulded samples. For the formulation of said expression, the Microsoft Excel program was used to perform a multiple linear regression with the variables related to the friction angle, resulting in a correction expression that improves the friction angles of the Direct Shear Test by 63.69 %. / Tesis