Phase Synchrony (PS) and coherence analyses of stochastic time series - tools to discover brain tissue pathways traveled by electrical signals - are considered for the specific purpose of processing of the electroencephalogram (EEG). We propose the Phase Synchrony Processor (PSP), as a tool for implementing phase synchrony analysis, and examine its properties on the basis of known signals. Long observation times and wide filter bandwidths can decrease bias in PS estimates. The value of PS is affected by the difference in frequency of the sequences being analyzed and can be related to that frequency difference by the periodic sinc function. PS analysis of the EEG shows that the average PS is higher - for a number of electrode pairs - for non-ADHD than for ADHD participants. The difference is more pronounced in the δ rhythm (0-3 Hz) and in the γ rhythm (30-50 Hz) PS. The Euclidean classifier with electrode masking yields 66 % correct classification on average for ADHD and non-ADHD subjects using the δ and γ1 rhythms. We observed that the average γ1 rhythm PS is higher for the eyes closed condition than for the eyes open condition. The latter may potentially be used for vigilance monitoring. The Euclidean discriminator with electrode masking shows an average percentage of correct classification of 78 % between the eyes open and eyes closed subject conditions. We develop a model for a pair of EEG electrodes and a model-based MS coherence estimator aimed at processing short (i.e. 20 samples) EEG frames. We verify that EEG sequences can be modeled as AR(3) processes degraded by additive white noise with an average SNR of approximately 11-12 dB. Application of the MS coherence estimator to the EEG suggests that MS coherence is generally higher for non-ADHD individuals than for ADHD participants when evaluated for the θ rhythm of EEG. Also, MS coherence is consistently higher for ADHD subjects than for the majority of non-ADHD individuals when computed for the low end of the δ rhythm (i.e. below 1 Hz). ADHD produces more measurable effects in the frontal lobe EEG and for participants performing attention intensive tasks. / Ph. D.

No description available.

In many clinical studies, continuous variables such as age, blood pressure and cholesterol are measured and analyzed. Often clinicians prefer to categorize these continuous variables into different groups, such as low and high risk groups. The goal of this work is to find the cutpoint of a continuous variable where the transition occurs from low to high risk group. Different methods have been published in literature to find such a cutpoint. We extended the methods of Contal and O’Quigley (1999) which was based on the log-rank test and the methods of Klein and Wu (2004) which was based on the Score test to find the cutpoint of a continuous covariate. Since the log-rank test is a nonparametric method and the Score test is a parametric method, we are interested to see if an extension of the parametric procedure performs better when the distribution of a population is known. We have developed a method that uses the parametric score residuals to find the cutpoint. The performance of the proposed method will be compared with the existing methods developed by Contal and O’Quigley and Klein and Wu by estimating the bias and mean square error of the estimated cutpoints for different scenarios in simulated data.

Made available in DSpace on 2014-06-11T19:31:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-12-05Bitstream added on 2014-06-13T19:02:04Z : No. of bitstreams: 1 assuncao_hf_dr_botfca.pdf: 2405298 bytes, checksum: 8e84fd2e177909f6f5d16a6bb2bacec6 (MD5) / Neste trabalho é proposto um modelo paramétrico para calcular a irradiância solar ultravioleta global e suas componentes. As transmitâncias referentes à absorção do ozônio, aos espalhamentos de Rayleigh e das nuvens e, à extinção dos aerossóis foram parametrizadas após a integração numérica das fórmulas espectrais, entre 290 a 400 nm. As componentes difusas foram desenvolvidas com base nos trabalhos de Brine e Iqbal (1983), Justus e Paris (1985), Bird e Riordan (1986) e Gueymard (1995). A equação de Van Heuklon (1979) foi incorporada ao modelo, como parâmetro de entrada, para calcular o conteúdo de ozônio e conseqüentemente a transmitância do ozônio à radiação solar direta. Também, foram incorporadas ao sistema a técnica de Pinazo et al. (1995) que permite o cálculo aproximado do índice de turbidez de Ångström, e a técnica de Assunção e Escobedo (2003) que calcula a transmitância média das nuvens, a partir das irradiância global e difusa. O modelo foi estruturado em VBA (Visual Basic for Application) e executado na planilha eletrônica Microsoft® Excel, requerendo, para isso, as variáveis de espaço (latitude, longitude e altitude), as variáveis de tempo (data e hora), e as variáveis meteorológicas (índice de claridade, fração direta, conteúdo de ozônio, umidade relativa e albedo da superfície) adquiridas no local em estudo. As irradiâncias ultravioletas previstas pelo modelo, após a calibração, foram comparadas com os correspondentes valores médios registrados, a cada 5 minutos, na Estação Radiométrica de Botucatu, SP (22° 51' S; 48° 26' W; 876 m), durante o período de janeiro de 2000 a julho de 2003. Os indicadores estatísticos de performance apontaram o modelo paramétrico como uma ferramenta adequada para calcular a irradiância solar ultravioleta. Foram feitas simulações com o modelo paramétrico, levando-se em... . / A parametric model is proposed to calculate ultraviolet solar irradiance components. The transmittances corresponding to ozone absorption, Rayleigh scattering, clouds diffusion and, aerosol extinction have been parameterized after the numeric integration of spectral formulae, from 290 to 400 nm. The diffuse components were developed with base in the works of Brine and Iqbal (1983), Justus and Paris (1985), Bird and Riordan (1986) and Gueymard (1995). Van Heuklon's equation has been joined to the model, as entrance parameter, to calculate ozone content and consequently its transmittance to the direct solar radiation. Also, Pinazo's technique that calculates Ångström's turbidity, and the algorithm of Assunção and Escobedo (2003) that calculates clouds transmittance, based on global and diffuse irradiances, were incorporated to the system. The parametric model was structured in VBA (Visual Basic for Application) to be run on Microsoft® Excel. This model requires as entrance parameters, the space (latitude, longitude and altitude), time (date and hour) and meteorological variables (clearness index, direct fraction, ozone content, relative air humidity and surface albedo) obtained on study place. The calibrated ultraviolet irradiances were compared with mean data of five minutes carried out on the Radiometric Station of Botucatu, SP (22° 51' S; 48° 26' W; 876 m), from January of 2000 to July of 2003. The statistical performance indicators pointed parametric model as tool appropriate to calculate the ultraviolet solar irradiance. Simulations were made with parametric model, taking into account the atmospheric conditions more frequent in Botucatu. Simulation results allowed to explain the effects produced on diffuse, direct and global ultraviolet irradiances by changes on the zenithal angle, on the ozone content, on the Ångström's turbidity and on the cloud optical thickness... (Complete abstract, click electronic address below).

Orientador: João Francisco Escobedo / Resumo: Neste trabalho é proposto um modelo paramétrico para calcular a irradiância solar ultravioleta global e suas componentes. As transmitâncias referentes à absorção do ozônio, aos espalhamentos de Rayleigh e das nuvens e, à extinção dos aerossóis foram parametrizadas após a integração numérica das fórmulas espectrais, entre 290 a 400 nm. As componentes difusas foram desenvolvidas com base nos trabalhos de Brine e Iqbal (1983), Justus e Paris (1985), Bird e Riordan (1986) e Gueymard (1995). A equação de Van Heuklon (1979) foi incorporada ao modelo, como parâmetro de entrada, para calcular o conteúdo de ozônio e conseqüentemente a transmitância do ozônio à radiação solar direta. Também, foram incorporadas ao sistema a técnica de Pinazo et al. (1995) que permite o cálculo aproximado do índice de turbidez de Ångström, e a técnica de Assunção e Escobedo (2003) que calcula a transmitância média das nuvens, a partir das irradiância global e difusa. O modelo foi estruturado em VBA (Visual Basic for Application) e executado na planilha eletrônica Microsoft® Excel, requerendo, para isso, as variáveis de espaço (latitude, longitude e altitude), as variáveis de tempo (data e hora), e as variáveis meteorológicas (índice de claridade, fração direta, conteúdo de ozônio, umidade relativa e albedo da superfície) adquiridas no local em estudo. As irradiâncias ultravioletas previstas pelo modelo, após a calibração, foram comparadas com os correspondentes valores médios registrados, a cada 5 minutos, na Estação Radiométrica de Botucatu, SP (22° 51' S; 48° 26' W; 876 m), durante o período de janeiro de 2000 a julho de 2003. Os indicadores estatísticos de performance apontaram o modelo paramétrico como uma ferramenta adequada para calcular a irradiância solar ultravioleta. Foram feitas simulações com o modelo paramétrico, levando-se em... (Resumo completo, clicar acesso eletrônico abaixo). / Abstract: A parametric model is proposed to calculate ultraviolet solar irradiance components. The transmittances corresponding to ozone absorption, Rayleigh scattering, clouds diffusion and, aerosol extinction have been parameterized after the numeric integration of spectral formulae, from 290 to 400 nm. The diffuse components were developed with base in the works of Brine and Iqbal (1983), Justus and Paris (1985), Bird and Riordan (1986) and Gueymard (1995). Van Heuklon's equation has been joined to the model, as entrance parameter, to calculate ozone content and consequently its transmittance to the direct solar radiation. Also, Pinazo's technique that calculates Ångström's turbidity, and the algorithm of Assunção and Escobedo (2003) that calculates clouds transmittance, based on global and diffuse irradiances, were incorporated to the system. The parametric model was structured in VBA (Visual Basic for Application) to be run on Microsoft® Excel. This model requires as entrance parameters, the space (latitude, longitude and altitude), time (date and hour) and meteorological variables (clearness index, direct fraction, ozone content, relative air humidity and surface albedo) obtained on study place. The calibrated ultraviolet irradiances were compared with mean data of five minutes carried out on the Radiometric Station of Botucatu, SP (22° 51' S; 48° 26' W; 876 m), from January of 2000 to July of 2003. The statistical performance indicators pointed parametric model as tool appropriate to calculate the ultraviolet solar irradiance. Simulations were made with parametric model, taking into account the atmospheric conditions more frequent in Botucatu. Simulation results allowed to explain the effects produced on diffuse, direct and global ultraviolet irradiances by changes on the zenithal angle, on the ozone content, on the Ångström's turbidity and on the cloud optical thickness... (Complete abstract, click electronic address below). / Doutor

More and more sensitive information is communicated digitally and with thatcomes the demand for security and privacy on the services being used. An accurateQoS metric for these services are of interest both for the customer and theservice provider. This thesis has investigated the impact of different parameterson the perceived voice quality for encrypted VoIP using a PESQ score as referencevalue. Based on this investigation a parametric prediction model has been developedwhich outputs a R-value, comparable to that of the widely used E-modelfrom ITU. This thesis can further be seen as a template for how to construct modelsof other equipments or codecs than those evaluated here since they effect theresult but are hard to parametrise. The results of the investigation are consistent with previous studies regarding theimpact of packet loss, the impact of jitter is shown to be significant over 40 ms.The results from three different packetizers are presented which illustrates theneed to take such aspects into consideration when constructing a model to predictvoice quality. The model derived from the investigation performs well withno mean error and a standard deviation of the error of a mere 1:45 R-value unitswhen validated in conditions to be expected in GSM networks. When validatedagainst an emulated 3G network the standard deviation is even lower.v

Dynamical systems are mathematical models of physical phenomena widely used throughout the world today. When a dynamical system is too large to effectively use, we turn to model reduction to obtain a smaller dynamical system that preserves the behavior of the original. In many cases these models depend on one or more parameters other than time, which leads to the field of parametric model reduction. Constructing a parametric reduced-order model (ROM) is not an easy task, and for very large parametric systems it can be difficult to know how well a ROM models the original system, since this usually involves many computations with the full-order system, which is precisely what we want to avoid. Building off of efficient 𝐻-infinity approximations, we develop a greedy algorithm for efficiently modeling large-scale parametric dynamical systems in an 𝐻₂-sense. We demonstrate the effectiveness of this greedy search on a fluid problem, a mechanics problem, and a thermal problem. We also investigate Bayesian optimization for solving the optimization subproblem, and end with extending this algorithm to work with MIMO systems. / Master of Science / In the past century, mathematical modeling and simulation has become the third pillar of scientific discovery and understanding, alongside theory and experimentation. Mathematical models are used every day, and are essential to modern engineering problems. Some of these mathematical models depend on quantities other than just time, parameters such as the viscosity of a fluid or the strength of a spring. These models can sometimes become so large and complicated that it can take a very long time to run simulations with the models. In such a case, we use parametric model reduction to come up with a much smaller and faster model that behaves like the original model. But when these large models vary highly with the parameters, it can also become very expensive to reduce these models accurately. Algorithms already exist for quickly computing reduced-order models (ROMs) with respect to one measure of how "good" the ROM is. In this thesis we develop an algorithm for quickly computing the ROM with respect to a different measure - one that is more closely tied to how the models are simulated.

Infrastructure management must move from a perspective that may singularly emphasize facility condition assessment to a broader view that involves nonphysical factors, which may substantially impact facility performance and shorten its service life. Socioeconomic, technological, regulatory, and user value changes can substantially increase the service expectations of existing facilities. Based on a theoretical framework drawn from prior work, this research develops a new approach to model infrastructure performance and assess factors that influence the remaining service life of highway bridges. Key parameters that impact the serviceability of highway bridges are identified and incorporated into a system dynamics model. This platform supports parametric scenario analysis and is applied in several cases to test how various factors influence bridge service life and performance. This decision support system provides a new approach for modeling serviceability over time and gives decision-makers an indication of: (a) the gap between society's service expectations and the service level provided and (b) the remaining service life of a highway bridge. / Ph. D.

Em levantamentos geodésicos planialtimétrico se faz necessário conhecer a qualidade das coordenadas estimadas de acordo com o tipo de aplicação a que se destinam. Este trabalho mostra de modo didático o estudo das teorias de análise de qualidade de rede GPS, baseando-se nas teorias de confiabilidade de rede propostos por Baarda, em 1968. As hipóteses estatísticas são fundamentais para elaboração dos testes para detecção de erros grosseiros (outliers), que constitui a base para a análise da confiabilidade de rede. Neste trabalho são propostas três estratégias, desenvolvidas em MathCAD, para a análise da qualidade do ajustamento. Os resultados obtidos foram comparados com os dos programas comerciais, Ski-Pro e Ashtech Solution, e também validados por medidas de campo feitas com estação total. As três estratégias propostas, para a rede em estudo implantada no Campus II da USP, apresentaram bons resultados / Geodetic planimetric survey requires the knowledge of the coordinates quality, estimated according to the final application. This work shows a didactic way on the study on theoretical analyses on quality of GPS networks, based on reliability network proposed by Baarda in 1968. Statistical hypotheses are fundamental to development of outliers’ detection tests, which consists the base for network reliability. In this work, three strategies are proposed, developed in MathCAD, to analyze adjustment quality. The results were compared with the results of two commercial programs, Ski-Pro and Ashtech Solution, and also field validation measurements with total station. The three proposed strategy, applied on a pilot network located at the Campus II of USP, gave good results

A utilização da tela de aço como reforço de pavimentos asfálticos no combate ao trincamento por reflexão é uma alternativa utilizada desde 1980 em países europeus. Uma revisão da literatura a respeito de sua utilização na reabilitação de pavimentos asfálticos, mostra que, a sua utilização acaba diminuindo o aparecimento de trincas nas camadas de revestimento, agindo como uma barreira contra a sua propagação, oferece resistência ao cisalhamento especialmente sob elevadas tensões e ainda, melhora a resistência à fadiga contribuindo para a longevidade do pavimento. Entretanto, o potencial de sua utilização tem sido pouco investigado em rodovias brasileiras. Neste contexto, insere-se esta pesquisa com o objetivo de avaliar o efeito do reforço gerado pela inserção da tela em revestimentos asfálticos para o uso em pavimentos flexíveis, com o propósito de tornar as estruturas rodoviárias menos onerosas com consequente aumento da sua vida útil. Para isso, foi realizada uma pesquisa visando à análise do seu desempenho em um trecho experimental localizado na rodovia SP-354, no Estado de São Paulo entre as cidades de Campo Limpo Paulista e Jarinu, fundamentado nas melhores práticas internacionais, recorrendo à observação em campo e laboratório, análise por meio de ensaios de módulo de resiliência e cálculos por retroanálise para verificação do efeito da inserção da tela, ainda propondo, uma metodologia de dimensionamento estrutural de reforço de pavimentos asfálticos considerando a faixa de valores de módulo de resiliência integrados com a tela e o fator de deflexão (K) para cálculo de espessura de reforço. Conclui-se que esta técnica de reforço tem potencial para prolongar a vida útil de revestimentos asfálticos em pavimentos flexíveis, com benefícios também para o desempenho da camada na fase pós-trincamento. Foram obtidos modelos que permitem dimensionar o revestimento asfáltico com o propósito de avaliar o efeito da tela de aço na zona tracionada da camada. Por fim, foi verificada através de um estudo de viabilidade técnica/econômica que a incorporação da tela de aço em pavimentos flexíveis é uma alternativa eficaz e de adequada viabilidade técnica e econômica. / The use of the steel mesh as reinforcement of asphalt pavements to combat reflective cracks by reflection is an alternative used since 1980 in European countries. A review of the literature on the use of the steel mesh in the rehabilitation of asphalt pavements shows that its use prevents the appearance of cracks acting as a barrier against its propagation, offers resistance to shearing especially under high tensions and also improves the resistance to fatigue contributing to the longevity of the pavement. However, the potential if its use has been little investigated in Brazilian highways. In this context this project is to develop a new technology for road construction and rehabilitation. The idea is to use steel mesh reinforcement in asphalt roads in order to make road structures more cost effective by improving the lifetime of new constructed roads and by developing an optimal rehabilitation method for existing roads. For this, a research was performed aiming at the analysis of its performance in an experimental section located on the highway SP-354, in the State of São Paulo between the cities of Campo Limpo Paulista and Jarinu, based on the best international practices, using observation of its behavior in the field and laboratory, analysis by means of resilient modulus tests and calculations by backcalculation to verify the effect of the insertion of the screen, still proposing, a methodology of asphalt pavement design considering the range of integrated resilience module values with the screen and the structural deflection reduction factor (K) admissible for reinforcement projects. It was concluded that this reinforcing technique has potential for improvements crack propagation post-cracking behavior and permanent deformation in the asphalt concrete surfacing layer, with a ten fold increase on fatigue life to be expected. A model was developed that may be employed for pavement design modifying a model based on the use of conventional fatigue laws for the asphalt concrete, if the grid is positioned at the tensile zone of the surfacing layer. Finally, it was verified through a technical / economic study that the incorporation of the steel mesh in flexible pavements is an effective alternative and of adequate technical and economic viability.