Ciclo de Palestras – Primeiro Semestre de 2025
Coordenação: Professora Maria Eulalia Vares e Widemberg da Silva Nobre
As palestras ocorrem de forma presencial às quartas-feiras às 15h30 na sala I-044-B, a menos de algumas exceções devidamente indicadas.
Lista completa (palestras previstas para datas futuras podem sofrer alterações)
Nesta apresentação, exploramos diversos aspectos da inferência Bayesiana aplicada. Abordamos a importância da distribuição a priori como uma função de regularização/penalidade, sua utilidade no tratamento de observações aberrantes e como ela pode ajudar a mitigar o viés de estimadores. Esses conceitos são exemplificados por meio de alguns resultados obtidos no passado com ex-alunos e colaboradores. Além disso, duas aplicações interessantes que motivam nossa atual agenda de pesquisa, serão apresentadas: Problemas Inversos em Equações Diferenciais Parciais (EDP) e Modelagem de Insolvência em Fundos de Pensão (FP).
This study introduces the effect of measurement error on Binary Randomized Response
Technique (RRT) models. We discuss a method for estimating and accounting for measurement
error in two basic RRT models (Warner and Greenberg models) and one more comprehensive
RRT model (Lovig et al. mixture model). Both theoretical and empirical results show that not
accounting for measurement errors leads to inaccurate estimates. We introduce estimators that
account for the effect of measurement errors. Furthermore, we introduce a new measure of model
privacy using an odds ratio statistic which offers better interpretability than traditional methods.
The cancer atlas edited by several countries is the main resource for the analysis of the geographic variation of cancer risk. Correlating the observed spatial patterns with known or hypothesized risk factors is time-consuming work for epidemiologists who need to deal with each cancer separately, breaking down the patterns according to sex and race. The recent literature has proposed to study more than one cancer simultaneously looking for common spatial risk factors. However, this previous work has two constraints: they consider only a very small (2–4) number of cancers previously known to share risk factors. In this article, we propose an exploratory method to search for latent spatial risk factors of a large number of supposedly unrelated cancers. The method is based on the singular value decomposition and nonnegative matrix factorization, it is computationally efficient, scaling easily with the number of regions and cancers. We carried out a simulation study to evaluate the method’s performance and apply it to cancer atlas from the USA, England, France, Australia, Spain, and Brazil. We conclude that with very few latent maps, which can represent a reduction of up to 90% of atlas maps, most of the spatial variability is conserved. By concentrating on the epidemiological analysis of these few latent maps a substantial amount of work is saved and, at the same time, high-level explanations affecting many cancers simultaneously can be reached. The work was partially supported by FAPEMIG and CNPq. Joint work with Mônica De Castro, Renato Assunção and Thais Menezes
See details in: Menezes, T. P. and Prates, M. O. and Assunção, R. and de Castro, M. S. M.. Latent Archetypes of the Spatial Patterns of Cancer. Statistics in Medicine, 43, 5115-5137, 2024