TEDE Coleção:http://www.bdtd.uerj.br/handle/1/37012024-03-29T14:24:09Z2024-03-29T14:24:09ZIdentificação de parâmetros e funções via abordagem bayesiana para detecção de melanomasNogueira, Adson Rodrigo Bragahttp://www.bdtd.uerj.br/handle/1/210642024-03-26T16:51:17Z2023-12-26T00:00:00ZTítulo: Identificação de parâmetros e funções via abordagem bayesiana para detecção de melanomas
Autor: Nogueira, Adson Rodrigo Braga
Primeiro orientador: Abreu, Luiz Alberto da Silva
Abstract: This work focuses on solving inverse problems in heat transfer, exploring their
application in estimating parameters and functions for detecting melanoma skin tumors.
Grounded in Bayesian methodologies, specifically Markov Chain Monte Carlo (MCMC),
which has played a crucial role in advancing engineering, it opens new possibilities for
tumor identification and treatment using the classical heat biotransfer equation. Heat
transfer in living tissues, particularly in tumor detection, poses a multidisciplinary challenge. The classical Pennes model stands out, allowing for the estimation of distinctive
thermal properties between healthy and unhealthy cells. However, the computational
implementation of these models faces challenges due to their complexity, resulting in considerable computational costs. In response, this dissertation proposes a two-dimensional inverse problem for the thermal characterization of melanoma tumors. The focus is on
considering realistic geometries and applying methodologies aimed at reducing computa tional costs. The use of Bayesian approaches is explored for their effective handling of uncertainties, providing a robust perspective for analysis. In conclusion, the relevance and consistency of the adopted approaches are highlighted, demonstrating the convergence of results obtained through different computational techniques, such as Wolfram Mathematica and COMSOL Multiphysics. The MCMC method proved consistent throughout the dissertation, successfully detecting tumor regions and providing information about the affected tissue’s geometry. Mesh refinement and uncertainty analysis proved essential for obtaining reliable estimates. The resulting distributions, mainly Gaussian and Gamma, offered valuable insights into parameters in healthy and tumor domains.
Instituição: Universidade do Estado do Rio de Janeiro
Tipo do documento: Dissertação2023-12-26T00:00:00ZSimulação do transporte de microplástico em zona costeira empregando a Plataforma MOHID: Estudos de caso no Estuário do Rio Macaé e na Baía de GuanabaraFigueira, Luana Ximeneshttp://www.bdtd.uerj.br/handle/1/203692024-02-27T18:26:37Z2022-02-15T00:00:00ZTítulo: Simulação do transporte de microplástico em zona costeira empregando a Plataforma MOHID: Estudos de caso no Estuário do Rio Macaé e na Baía de Guanabara
Autor: Figueira, Luana Ximenes
Primeiro orientador: Silva Neto, Antônio José da
Abstract: A microplastic environment contaminate has received attention from researchers, and
environmentalists. Currently, there are few models that simulate the trajectory of plastic debris. These models are used in order to predict the accesses and how they work according to the atmosphere. In this context, the objective of this work was to apply the hydrodynamic model, MOHID, with its Lagrangian module for a simulation of microplastics transport in the Macaé River Estuary and in the Guanabara Bay region. The platform used in the research has been elaborated in several processes that occur in estuaries, seas and oceans obtained, starting from field data for an adjustment of real models. It was concluded that the particle tracking module proved to be a significant tool for the study of the circulation of microplastics in the Macaé River and Guanabara Bay. The results extend to a lower level, since in both proportions they were more plastic, with the advance towards the sea, justifying the reason for the elevated Guanabara Bay. Finally, other simulations are published taking into account other factors, such as meteorological forces in the study region.
Instituição: Universidade do Estado do Rio de Janeiro
Tipo do documento: Dissertação2022-02-15T00:00:00ZSolução de problemas inversos do modelo Bevilacqua-Galeão de difusão anômala com dependência espacialMattos, Sulivan Carlos Xavierhttp://www.bdtd.uerj.br/handle/1/170012024-02-27T18:26:36Z2021-08-09T00:00:00ZTítulo: Solução de problemas inversos do modelo Bevilacqua-Galeão de difusão anômala com dependência espacial
Autor: Mattos, Sulivan Carlos Xavier
Primeiro orientador: Silva Neto, Antônio José da
Abstract: The main objective of this dissertation is the formulation and solution of the direct and inverse problem for the anomalous diffusion bi-flux model proposed by Bevilacqua and Galeão. To solve both problems, a spatial variation for some model parameters was used. It was considered the free substances, that is, the fraction of available substance for the diffusion and also the parameter known as reactivity coefficient, with spatial variation. In relation to the direct problem, it was presented a monodimensional solution to the model using the Finite Difference Method, seeking to evidence the difference in the concentration profile of the solutions, comparing to the model results using variable and constant parameters. An inverse problem for parameters estimation, with spatial variation, was formulated and solved employing the Modified Luus-Jaakola (MLJ), Differential Evolution (DE) and Firefly (FF) stochastic methods. A sensitivity analyses was performed for each of the parameters, whose purpose was to identify optimal experimental conditions to enable the solution of the inverse problem. Through the results obtained in each case, it is possible to verify that the spatial variation of parameters directly affects the diffusion velocity. In relation to estimation of these parameters, the efficiency of each method used was observed, especially when the experimental data were noiseless. New formulations proposed by Bevilacqua were also discussed in this work.
Instituição: Universidade do Estado do Rio de Janeiro
Tipo do documento: Dissertação2021-08-09T00:00:00ZEstimação de energia baseada em filtragem casada para um calorímetro operando em condições de empilhamento de sinaisRocha, Geovane Pacheco dahttp://www.bdtd.uerj.br/handle/1/169962024-02-27T18:26:37Z2021-10-27T00:00:00ZTítulo: Estimação de energia baseada em filtragem casada para um calorímetro operando em condições de empilhamento de sinais
Autor: Rocha, Geovane Pacheco da
Primeiro orientador: Peralva, Bernardo Sotto-Maior
Abstract: The description and reproduction of physical phenomena are a common challenge in the field of computational modeling. In the context of high-energy calorimetry, the particle energy produced from collisions is absorbed and sampled in the form of a digitized signal. In a high event-rate and luminosity conditions, the signal pile-up effect may arise due to the high occupancy of the detector’s readout channels, causing the distortion of the expected signal. In this context, this work evaluates the performance of the method known as Matched Filter, by applying it in two distinct approaches called Deterministic Matched Filter and Stochastic Matched Filter. These approaches will be compared to the current method applied in the ATLAS Tile Calorimeter (TileCal), known as Optimal Filter. For the efficiency analysis, an computational environment was created to contain simulated data considering different signal pile-up conditions in the TileCal. Furthermore, a hybrid environment was also created, consisting in signals whose amplitudes are previously known and added to different conditions of pile-up noise. For both analysis, different signal-noise ratio conditions were considered. The results show that the Stochastic Matched Filter presented high accuracy in estimating the amplitude, becoming an alternative for the TileCal energy estimation task.
Instituição: Universidade do Estado do Rio de Janeiro
Tipo do documento: Dissertação2021-10-27T00:00:00Z