Termodinâmica de um gás de fótons no contexto de eletrodinâmicas não-lineares

The objective of this dissertation is the development of a general formalism to analyze the thermodynamical properties of a photon gas under the context of nonlinear electrodynamics (NLED). To this end it is obtained, through the systematic analysis of Maxwell s electromagnetism (EM) properties, the general dependence of the Lagrangian that describes this kind of theories. From this Lagrangian and in the background of classical field theory, we derive the general dispersion relation that photons must obey in terms of a background field and the NLED properties. It is important to note that, in order to achieve this result, an aproximation has been made in order to allow the separation of the total electromagnetic field into a strong background electromagnetic field and a perturbation. Once the dispersion relation is in hand, the usual Bose-Einstein statistical procedure is followed through which the thermodynamical properties, energy density and pressure relations are obtained. An important result of this work is the fact that equation of state remains identical to the one obtained under EM. Then, two examples are made where the thermodynamic properties are explicitly derived in the context of two NLED, Born-Infelds and a quadratic approximation. The choice of the first one is due to the vast appearance in literature and, the second one, because it is a first order approximation of a large class of NLED. Ultimately, both are chosen because of their simplicity. Finally, the results are compared to EM and interpreted, suggesting possible tests to verify the internal consistency of NLED and motivating further developement into the formalism s quantum case

Modelo de risco controlado por resseguro e desigualdades para a probabilidade de ruína

In the work reported here we present theoretical and numerical results about a Risk Model with Interest Rate and Proportional Reinsurance based on the article Inequalities for the ruin probability in a controlled discrete-time risk process by Ros ario Romera and Maikol Diasparra (see [5]). Recursive and integral equations as well as upper bounds for the Ruin Probability are given considering three di erent approaches, namely, classical Lundberg inequality, Inductive approach and Martingale approach. Density estimation techniques (non-parametrics) are used to derive upper bounds for the Ruin Probability and the algorithms used in the simulation are presented

Usando a história da resolução de alguns problemas para introduzir conceitos: sistemas lineares, determinantes e matrizes.

In this work we studied the method to solving linear equations system, presented in the book titled "The nine chapters on the mathematical art", which was written in the first century of this era. This work has the intent of showing how the mathematics history can be used to motivate the introduction of some topics in high school. Through observations of patterns which repeats itself in the presented method, we were able to introduce, in a very natural way, the concept of linear equations, linear equations system, solution of linear equations, determinants and matrices, besides the Laplacian development for determinants calculations of square matrices of order bigger than 3, then considering some of their general applications

Os eventos geográficos e a expansão urbana de Caicó desigualdades e coexistências na URBE

This research arose from the interest on the investigation about urban expansion from Caicó. Since its creation as a village and its ascent to the condition of city, but especially , the occurred expansion from the 70s, when the local cotton economy begins to present signs of exhaustion. The central theme of this work consists on the importance of the geographical events and its relations with the phenomenon of the urban expansion from Caicó that served us as empirical basis. In relation to the events, that appear as elements of analysis on the works from the Professor Milton Santos, especially on the book Nature of Space , they appear as a kind of urban extensors energizing the areas where are installed. Understood by us as a vehicle of one or more possibilities, according to Santos, (1999) we listed some events occurred in the caicoense urbs a nd we divided them into principal and derivative ones, such events implemented from their structures, forms and functions, through processes that resulted and still continue to result the enlargement of the caicoense urban perimeter , densifications enough important for this urban expansion. The technical periods of cattle raising , cotton, as well as the tertiary city and its connections with the role of fast men, as well as slow men is also important aspect in the body of this work. It is still pointed out the inequalities and the coexistences that are generated on the basis of these connections and finally we discussed the positive and negative consequences elapsed from the phenomenon of the urban expansion

Desigualdades socioespaciais: produção do espaço e política habitacional de interesse social em Parnamirim/RN

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Pobreza e desigualdades socioterritorias: uma problematização acerca da perspectiva territorial nas politicas públicas sociais no município de Pau dos Ferros/RN

El presente trabajo se constituye en un estudio sobre la pobreza y las desigualdades socio territoriales en el Brasil, problematizando la perspectiva territorial de las políticas públicas sociales observando la distribución espacial del Índice de Desarrollo de las familias (IDF) en el municipio de Pau dos Ferros/RN, así como las principales políticas sociales, a ejemplo del Programa Bolsa Familia. En este sentido, el objetivo principal de esa disertación se dió en la tentativa de comprender la importancia de la lectura previa del territorio para la reflexión sobre la pobreza en su aspecto multidimensional y para la territorialización de las políticas Públicas sociales construidas en el intento de minimizar la problemática de la desigualdad social, observando la distribución espacial do IDF en el municipio de Pau dos Ferros/RN. A partir del objetivo general trazado, hicimos una revisión teórica sobre los temas, pobreza, desigualdades sociales y políticas públicas, en el primero caso atentando para el aspecto multidimensional de esta, abogando la importancia de analizarnos la pobreza no apenas por el nivel de rienda, pero considerando otras dimensiones que corroboran para la constitución del ser pobre, como habitaciones precarias, falta de saneamiento básico e infraestructura, el no acceso a la salud, la educación y los otros servicios que posibilitan el individuo vivir con el mejor dignidad. Comprendiendo la importancia del conocimiento previo del territorio para que ocurra las debidas reflexiones e intervenciones en la realidad territorial buscamos reflexionar acerca de ese concepto en sus nexos con la construcción e implementación de las políticas públicas sociales teniendo la Política Nacional de Asistencia Social (PNAS) como política esencial y también el el Programa Bolsa Familia (PBF), una vez que buscamos compreender su importancia a partir de la visión del sujeto, o sea las beneficiadas del PBF en el Municipio de Pau dos Ferros. Para tanto, hicimos entrevistas orales con las beneficiadas del PBF que fueron elegidas aislada a partir de los equipos del CRAS, además de la aplicación de cuestionarios semiesctructurados y abiertos con gestores y asistentes sociales del muninicipio.Buscamos además trabajar con algunos datos del CadÚnico para el município en estudio proponiendo analisar las condiciones sociales y económicas de las famílias cadastradas. Algunos resultados fueron posibles, a saber, es necesario interpretarse la pobreza a partir de varias dimensiones para no tener el riesgo de quedarnos solamente en la perspectiva financiera, o sea de la rienda, que mismo sirva para lo emergencial no es suficiente para transformar las condiciones de vida de las famílias; PNAS puede ser considerada como un avanzo de la política social en el Brasil una vez que posuye importancia fundamental en la familia. Sin embargo, es preciso avanzar en la interpretación del territorio que en la política y en el habla de los agentes sociales , es interpretación apenas como un recorte donde deberán ocurrir las acciones para minimizar la pobreza ; al fin, o PBF es un programa de urgencia moral una vez que combate lo mas emergencial que es el directo de sobrevivir , pero aun no conseguió transformar de una manera significativa la pobreza en el país

Critério de correntropia no treinamento de redes fuzzy wavelet neural networks para identificação de sistemas dinâmicos não lineares

The great interest in nonlinear system identification is mainly due to the fact that a large amount of real systems are complex and need to have their nonlinearities considered so that their models can be successfully used in applications of control, prediction, inference, among others. This work evaluates the application of Fuzzy Wavelet Neural Networks (FWNN) to identify nonlinear dynamical systems subjected to noise and outliers. Generally, these elements cause negative effects on the identification procedure, resulting in erroneous interpretations regarding the dynamical behavior of the system. The FWNN combines in a single structure the ability to deal with uncertainties of fuzzy logic, the multiresolution characteristics of wavelet theory and learning and generalization abilities of the artificial neural networks. Usually, the learning procedure of these neural networks is realized by a gradient based method, which uses the mean squared error as its cost function. This work proposes the replacement of this traditional function by an Information Theoretic Learning similarity measure, called correntropy. With the use of this similarity measure, higher order statistics can be considered during the FWNN training process. For this reason, this measure is more suitable for non-Gaussian error distributions and makes the training less sensitive to the presence of outliers. In order to evaluate this replacement, FWNN models are obtained in two identification case studies: a real nonlinear system, consisting of a multisection tank, and a simulated system based on a model of the human knee joint. The results demonstrate that the application of correntropy as the error backpropagation algorithm cost function makes the identification procedure using FWNN models more robust to outliers. However, this is only achieved if the gaussian kernel width of correntropy is properly adjusted.

Um estudo sobre polinômios matriciais

This research work aims to make a study of the algebraic theory of matrix monic polynomials, as well as the definitions, concepts and properties with respect to block eigenvalues, block eigenvectors and solvents of P(X). We investigte the main relations between the matrix polynomial and the Companion and Vandermonde matrices. We study the construction of matrix polynomials with certain solvents and the extention of the Power Method, to calculate block eigenvalues and solvents of P(X). Through the relationship between the dominant block eigenvalue of the Companion matrix and the dominant solvent of P(X) it is possible to obtain the convergence of the algorithm for the dominant solvent of the matrix polynomial. We illustrate with numerical examples for diferent cases of convergence.

Contribuição ao estudo de treliças não lineares considerando efeitos térmicos

This work presents the numerical analysis of nonlinear trusses summited to thermomechanical actions with Finite Element Method (FEM). The proposed formulation is so-called positional FEM and it is based on the minimum potential energy theorem written according to nodal positions, instead of displacements. The study herein presented considers the effects of geometric and material nonlinearities. Related to dynamic problems, a comparison between different time integration algorithms is performed. The formulation is extended to impact problems between trusses and rigid wall, where the nodal positions are constrained considering nullpenetration condition. In addition, it is presented a thermodynamically consistent formulation, based on the first and second law of thermodynamics and the Helmholtz free-energy for analyzing dynamic problems of truss structures with thermoelastic and thermoplastic behavior. The numerical results of the proposed formulation are compared with examples found in the literature.

Efeito de diferentes divisões territoriais na flutuação aleatória de indicadores socioeconômicos relacionados à determinação social da saúde

This research aimed to analyse the effect of different territorial divisions in the random fluctuation of socio-economic indicators related to social determinants of health. This is an ecological study resulting from a combination of statistical methods including individuated and aggregate data analysis, using five databases derived from the database of the Brazilian demographic census 2010: overall results of the sample by weighting area. These data were grouped into the following levels: households; weighting areas; cities; Immediate Urban Associated Regions and Intermediate Urban Associated Regions. A theoretical model related to social determinants of health was used, with the dependent variable Household with death and as independent variables: Black race; Income; Childcare and school no attendance; Illiteracy; and Low schooling. The data was analysed in a model related to social determinants of health, using Poisson regression in individual basis, multilevel Poisson regression and multiple linear regression in light of the theoretical framework of the area. It was identified a greater proportion of households with deaths among those with at least one black resident, lower-income, illiterate, who do not attend or attended school or day-care and less educated. The analysis of the adjusted model showed that most adjusted prevalence ratio was related to Income, where there is a risk value of 1.33 for households with at least one resident with lower average personal income to R$ 655,00 (Brazilian current). The multilevel analysis demonstrated that there was a context effect when the variables were subjected to the effects of areas, insofar as the random effects were significant for all models and with different prevalence rates being higher in the areas with smaller dimensions - Weighting areas with coefficient of 0.035 and Cities with coefficient of 0.024. The ecological analyses have shown that the variable Income and Low schooling presented explanatory potential for the outcome on all models, having income greater power to determine the household deaths, especially in models related to Immediate Urban Associated Regions with a standardized coefficient of -0.616 and regions intermediate urban associated regions with a standardized coefficient of -0.618. It was concluded that there was a context effect on the random fluctuation of the socioeconomic indicators related to social determinants of health. This effect was explained by the characteristics of territorial divisions and individuals who live or work there. Context effects were better identified in the areas with smaller dimensions, which are more favourable to explain phenomena related to social determinants of health, especially in studies of societies marked by social inequalities. The composition effects were better identified in the Regions of Urban Articulation, shaped through mechanisms similar to the phenomenon under study.

Implementação da rotina de unfolding para determinação de distribuição de tamanho de grãos esféricos via distribuição de interceptos lineares e de área de seção

Na unfolding method of linear intercept distributions and secction área distribution was implemented for structures with spherical grains. Although the unfolding routine depends on the grain shape, structures with spheroidal grains can also be treated by this routine. Grains of non-spheroidal shape can be treated only as approximation. A software was developed with two parts. The first part calculates the probability matrix. The second part uses this matrix and minimizes the chi-square. The results are presented with any number of size classes as required. The probability matrix was determined by means of the linear intercept and section area distributions created by computer simulation. Using curve fittings the probability matrix for spheres of any sizes could be determined. Two kinds of tests were carried out to prove the efficiency of the Technique. The theoretical tests represent ideal cases. The software was able to exactly find the proposed grain size distribution. In the second test, a structure was simulated in computer and images of its slices were used to produce the corresponding linear intercept the section area distributions. These distributions were then unfolded. This test simulates better reality. The results show deviations from the real size distribution. This deviations are caused by statistic fluctuation. The unfolding of the linear intercept distribution works perfectly, but the unfolding of section area distribution does not work due to a failure in the chi-square minimization. The minimization method uses a matrix inversion routine. The matrix generated by this procedure cannot be inverted. Other minimization method must be used