Submitted by WILLIAN DIEGO OLIVEIRA null (willian@ibilce.unesp.br) on 2017-09-18T03:59:17Z No. of bitstreams: 1 Tese Final.pdf: 21063949 bytes, checksum: 766c3ca9aab9ca1a33dd27bf06043b1d (MD5) / Approved for entry into archive by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-09-19T19:05:58Z (GMT) No. of bitstreams: 1 oliveira_wd_dr_sjrp.pdf: 21063949 bytes, checksum: 766c3ca9aab9ca1a33dd27bf06043b1d (MD5) / Made available in DSpace on 2017-09-19T19:05:58Z (GMT). No. of bitstreams: 1 oliveira_wd_dr_sjrp.pdf: 21063949 bytes, checksum: 766c3ca9aab9ca1a33dd27bf06043b1d (MD5) Previous issue date: 2017-05-11 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Estudamos tópicos relacionados a zeros de séries de Dirichlet e de funções inteiras. Boa parte da tese é voltada à localização de zeros de séries de Dirichlet via critérios de densidade. Estabelecemos o critério de Nyman-Beurling para uma ampla classe de séries de Dirichlet e o critério de Báez-Duarte para L-funções de Dirichlet em semi-planos R(s)>1/2, para p ∈ (1,2], bem como para polinômios de Dirichlet em qualquer semi-plano R(s)>r. Um análogo de uma cota inferior de Burnol relativa ao critério de Báez-Duarte foi estabelecido para polinômios de Dirichlet. Uma das ferramentas principais na prova deste último resultado é a solução de um problema extremo natural para polinômios de Dirichlet inspirado no resultado de Báez-Duarte. Provamos que os sinais dos coeficientes de Maclaurin de uma vasta subclasse de funções inteiras da classe de Laguerre-Pólya possuem um comportamento regular. / We study topics related to zeros of Dirichlet series and entire functions. A large part of the thesis is devoted to the location of zeros of Dirichlet series via density criteria. We establish the Nyman-Beruling criterion for a wide class of Dirichlet series and the Báez-Duarte criterion for Dirichlet L-functions in the semi-plane R(s)>1/p, for p ∈ (1,2], as well as for zeros of Dirichlet polynomials in any semi-plane R(s)>r. An analog for the case of Dirichlet polynomials of a result of Burnol which is closely related to Báez-Duarte’s one is also established. A principal tool in the proof of the latter result is the solution of a natural extremal problem for Dirichlet polynomials inspired by Báez-Duarte’s result. We prove that the signs of the Maclaurin coefficients of a wide class of entire functions that belong to the Laguerre-Pólya class posses a regular behavior. / FAPESP: 2013/14881-9

Apesar de serem intensamente estudados em muitos países que caminham na vanguarda do conhecimento, os métodos sem malha ainda são pouco explorados pelas universidades brasileiras. De modo a gerar uma maior difusão ou, para a maioria, fazer sua introdução, esta dissertação objetiva efetuar o entendimento dos métodos sem malha baseando-se em aplicações atinentes à mecânica dos sólidos. Para tanto, são apresentados os conceitos primários dos métodos sem malha e o seu desenvolvimento histórico desde sua origem no método smooth particle hydrodynamic até o método da partição da unidade, sua forma mais abrangente. Dentro deste contexto, foi investigada detalhadamente a forma mais tradicional dos métodos sem malha: o método de Galerkin sem elementos, e também um método diferenciado: o método de interpolação de ponto. Assim, por meio de aplicações em análises de barras e chapas em estado plano de tensão, são apresentadas as características, virtudes e deficiências desses métodos em comparação aos métodos tradicionais, como o método dos elementos finitos. É realizado ainda um estudo em uma importante área de aplicação dos métodos sem malha, a mecânica da fratura, buscando compreender como é efetuada a representação computacional da trinca, com especialidade, por meio dos critérios de visibilidade e de difração. Utilizando-se esses critérios e os conceitos da mecânica da fratura, é calculado o fator de intensidade de tensão através do conceito da integral J. / Meshless are certainly very researched in many countries that are in state of art of scientific knowledge. However these methods are still unknown by many brazilian universities. To create more diffusion or, for many people, to introduce them, this work tries to understand the meshless based on solid mechanic applications. So basic concepts of meshless and its historic development are introduced since its origin, with smooth particle hydrodynamic until partition of unity, its more general form. In this context, most traditional form of meshless was investigated deeply: element free Galerkin method and also another different method: point interpolation method. This way characteristics, advantages and disadvantages, comparing to finite elements methods, are introduced by applications in analyses in bars and plates in state of plane stress. This work still researched an important area of meshless application, fracture mechanical, to understand how a crack is computationally represented, particularly, with visibility and diffraction criterions. By these criterions and using fracture mechanical concepts, stress intensity factor is calculated by J-integral concept.

Metodologias para obtenção do tamanho amostral para estimar a concentração de organismos em água de lastro e verificar normas internacionais são desenvolvidas sob uma abordagem bayesiana. Consideramos os critérios da cobertura média, do tamanho médio e da minimização do custo total sob os modelos Poisson com distribuição a priori gama e binomial negativo com distribuição a priori Pearson Tipo VI. Além disso, consideramos um processo Dirichlet como distribuição a priori no modelo Poisson com o propósito de obter maior flexibilidade e robustez. Para fins de aplicação, implementamos rotinas computacionais usando a linguagem R. / Sample size methodologies for estimating the organism concentration in ballast water and for verifying international standards are developed under a Bayesian approach. We consider the criteria of average coverage, of average length and of total cost minimization under the Poisson model with a gamma prior distribution and the negative binomial model with a Pearson type VI prior distribution. Furthermore, we consider a Dirichlet process as a prior distribution in the Poisson model with the purpose to gain more flexibility and robustness. For practical applications, we implemented computational routines using the R language.

The presence of the compressive or tensile thermal residual stresses in layers of a ceramic laminate induced due to different volume change of each layer´s material during the cooling from the sintering temperature can considerably affect resistivity of ceramics against contact damage. Within this work 2D parametric FEM models were created, in order to study the effect of the surface layer thickness, residual stress values and indenting body dimension on the initiation and propagation of the cone crack in the surface layer of the laminate. For the analysis of the critical conditions for the crack initiation, the coupled stress-energy criterion was used and for the determination of the direction of crack propagation we used the maximum tangential stress criterion. The results show that compressive thermal stresses in the surface layer increase the critical force for the crack initiation, shorten the crack distance from the contact area and shorten the occurred crack itself. Moreover, the compressive stresses enlarge the angle of the crack declination during the propagation process which cause an earlier crack arrest. The tensile thermal stresses have exactly the opposite effect. Results of simulations were compared to experimental results but due to lack of available measurements, the verification is partially limited.

This Master´s thesis deals with the determination of the propagation directions of primary crack in the rail vehicles wheel under operating conditions. The aim of this work is the stress-strain analysis with using fracture mechanics to examinate behaviour of primary cracks for different operating conditions, i.e. rotation, rotation with contact and assessment of refracted cracks with applied rotation and contact.

The detection of multiple outliers can be interpreted as a model selection problem. Models that can be selected are the null model, which indicates an outlier free set of observations, or a class of alternative models, which contain a set of additional bias parameters. A common way to select the right model is by using a statistical hypothesis test. In geodesy data snooping is most popular. Another approach arises from information theory. Here, the Akaike information criterion (AIC) is used to select an appropriate model for a given set of observations. The AIC is based on the Kullback-Leibler divergence, which describes the discrepancy between the model candidates. Both approaches are discussed and applied to test problems: the fitting of a straight line and a geodetic network. Some relationships between data snooping and information criteria are discussed. When compared, it turns out that the information criteria approach is more simple and elegant. Along with AIC there are many alternative information criteria for selecting different outliers, and it is not clear which one is optimal.

In this dissertation, first we consider the problem of testing homogeneity and order in a contaminated normal model, when the data is correlated under some known covariance structure. To address this problem, we developed a moment based homogeneity and order test, and design weights for test statistics to increase power for homogeneity test. We applied our test to microarray about Down’s syndrome. This dissertation also studies a singular Bayesian information criterion (sBIC) for a bivariate hierarchical mixture model with varying weights, and develops a new data dependent information criterion (sFLIC).We apply our model and criteria to birth- weight and gestational age data for the same model, whose purposes are to select model complexity from data.

In this research, a novel, unique systematic procedure was implemented to investigate the influence of the fracture networks and confining stresses on the jointed coal mass strength (JCMS). Both a laboratory experimental scheme and a numerical modeling scheme were carried out at the 3-D level. The laboratory experiments were performed to achieve the following three goals. Firstly, the geomechanical properties for the intact coal and coal discontinuities were estimated through the laboratory geomechanical property tests. Secondly, naturally existing fracture networks in the cubic coal blocks were first detected by the industrial Computed Tomography (CT) scanning technique and then quantified by the fracture tensor based methodology. Thirdly, polyaxial tests were conducted on the same cubic coal blocks to obtain the JCMS values under different confining stresses. With respect to the numerical modeling, PFC^3D and 3DEC software packages were used to simulate the polyaxial compression tests for intact and jointed cubic coal blocks, respectively. From more than twenty intact rock strength criteria, nine criteria were selected for this research. The intact coal strength data bank obtained from PFC^3D modeling was used to evaluate the applicability of nine different intact rock strength criteria. A modified grid search (MGS) procedure is proposed and used to find the best fitting parameter values and calculate the coefficient of determination (R²) values for each criterion. These criteria are compared in detail using the following features: R² values, σ₁ - σ₂ plots for different σ₃, shapes on the deviatoric planes, linearity or nonlinearity on the meridian planes. The regression analysis and the MGS procedure were found to be equivalent in finding the best fitting parameter values for a certain intact rock strength criterion. Through the comparisons, the modified Wiebols-Cook and modified Lade criteria were found to provide the highest R² values and fit the intact coal strength data best on the σ₁ - σ₂ coordinate plane and meridian planes. Based on the appearances on the deviatoric plane, the nine intact rock strength criteria are categorized into three types: the single shear stress criteria, the octahedral shear stress criteria and the criteria incorporating the maximum principal shear stress and partial intermediate principal shear stress. The relative positions of the different criteria on two specific meridian planes are also discussed. The geometric model of the jointed coal block was first set up by incorporating the fracture network constructed from the CT scanning into the intact coal block using a modified fictitious joint procedure. The numerical parameter values of intact coal and coal discontinuities were then calibrated and validated through a trial and error procedure using the laboratory test results of some selected samples. Next the JCMS data bank was consummated by performing a four-phase numerical investigation on several jointed coal blocks having selected fracture networks and five additional artificial fracture networks under different confining stress combinations. Finally, a new empirical coal mass strength criterion was developed to estimate the JCMS values at the 3-D level. The developed new model is capable of capturing the scale effect and anisotropic strength behaviors. It can also be applied to rock masses having approximately orthogonal fracture systems or for masses where fracture system can be reduced to an equivalent orthogonal fracture system.The following new contributions were made in this dissertation to advance the existing state-of-art on the dissertation topic: (a) A new, unique methodology as shown in Fig. 1.1 incorporating the following aspects was used to develop a new 3-D coal mass strength criterion: a complete set of geomechanical property tests, fracture network detection and quantification, polyaxial compression tests, numerical decomposition techniques; (b) A new procedure was developed to construct the fracture network in the coal cubes starting from CT scans to perform numerical modeling using 3DEC. In this procedure, a modified fictitious joint framework was also proposed to extend the applicability of the original fictitious joint framework, which allows incorporating a large quantity of non-persistent joints with acceptable numerical calculation effort; (c) A new 3-D coal mass strength criterion was developed to incorporate the fracture network and 3-D confining stress system to capture the anisotropy and scale effect of coal mass strength. The proposed criterion not only includes the influence of the intermediate principal stress, which is ignored by some existing strength criteria, but also includes the intensity and orientation and size probability distributions of the fracture system explicitly by a fracture tensor based methodology, which is far more advanced than most of the current criteria that are based on rock mass classification systems having only scalar indices; (d) A modified grid search procedure was proposed and used to evaluate the applicability of nine different intact rock strength criteria. The best intact rock strength criteria applicable for the intact coal data obtained through PFC^3D modeling were found by performing the most detailed intact rock strength criteria evaluation incorporating σ₁ - σ₂ - σ₃ plots and behaviors on the deviatoric and meridian planes, which improves the understanding of the available intact rock strength criteria.

<p>Failure of bi-material interfaces is studied with the aim to quantify the influence of the induced stress concentrations on the strength of the interfaces. A simple point-stress criterion, used in conjunction with finite element calculations, is evaluated to provide strength predictions for bi-material bonded joints and inserts in polymer foam. The influence of local stress concentrations on the initiation of fracture at open and closed wedge bi-material interfaces is investigated. The joint combinations are analysed numerically and the strength predictions obtained from the point-stress criterion are verified in experiments. </p><p>The predictions are made using a simple point-stress criterion in combination with highly accurate finite element calculations. The point-stress criterion was known from earlier work to give accurate predictions of failure at cracks and notches but had to be slightly modified to become applicable for the studied configurations. The criterion showed to be generally applicable to the bi-material interfaces studied herein. Sensible predictions for the tendentious strength behaviour could be made with reasonable accuracy, including the prediction of crossover from local, joint-induced failure to global failure. </p><p>To study the micromechanical properties of a cellular solid with arbitrary topology, various models of a closed-cell foam are created on the basis of random Voronoi tessellations. The foam models are analysed using the finite element method and the effective elastic properties of the model cellular solids are determined. The calculated moduli are compared to the properties of a real reference foam and the numerical results show to be in very good agreement. </p><p>The mechanical properties of closed-cell, low-density cellular solids are governed by the stiffnesses of the cell edges and the cell faces. Models of idealised foam models with planar cell faces, cannot account for the curved faces found on some metal and polymer foams. Finite element models of closed-cell foams were created to analyse the influence of cell face curvature on the stiffness of the foam. By determining the elastic modulus for foams with non-planar cell faces, the effect of cell face curvature could be analysed as a function of the relative density and the distribution of solid material between cell edges and faces. </p><p>Foam models were generated from disturbed point distribution lattices and compared to models obtained from random distributions. The aim was to analyse if and how the geometry of the cells and their spatial arrangement influences the mechanical properties of a foam. The results suggest that the spatial arrangement and the geometry of the cells have significant influence on the properties of a foam. The elastic properties calculated for models from disturbed foam structures underestimated the elastic moduli of the foam, whereas models from random structures provided results which were in very good agreement with a reference foam.</p>

The costs of developing new pharmaceuticals have increased dramatically during the past decades. Contributing to these increased expenses are the increasingly extensive and more complex clinical trials required to generate sufficient evidence regarding the safety and efficacy of the drugs.  It is therefore of great importance to improve the effectiveness of the clinical phases by increasing the information gained throughout the process so the correct decision may be made as early as possible.   Optimal Design (OD) methodology using the Fisher Information Matrix (FIM) based on Nonlinear Mixed Effect Models (NLMEM) has been proven to serve as a useful tool for making more informed decisions throughout the clinical investigation. The calculation of the FIM for NLMEM does however lack an analytic solution and is commonly approximated by linearization of the NLMEM. Furthermore, two structural assumptions of the FIM is available; a full FIM and a block-diagonal FIM which assumes that the fixed effects are independent of the random effects in the NLMEM. Once the FIM has been derived, it can be transformed into a scalar optimality criterion for comparing designs. The optimality criterion may be considered local, if the criterion is based on singe point values of the parameters or global (robust), where the criterion is formed for a prior distribution of the parameters.  Regardless of design criterion, FIM approximation or structural assumption, the design will be based on the prior information regarding the model and parameters, and is thus sensitive to misspecification in the design stage.  Model based adaptive optimal design (MBAOD) has however been shown to be less sensitive to misspecification in the design stage.   The aim of this thesis is to further the understanding and practicality when performing standard and MBAOD. This is to be achieved by: (i) investigating how two common FIM approximations and the structural assumptions may affect the optimized design, (ii) reducing runtimes complex design optimization by implementing a low level parallelization of the FIM calculation, (iii) further develop and demonstrate a framework for performing MBAOD, (vi) and investigate the potential advantages of using a global optimality criterion in the already robust MBAOD.