Abstract: In this talk, I will start with a review of the characteristics of classical inverse problems before moving into Bayesian methods for inverse problems. The first Bayesian methodology I will discuss is the use of Gaussian Markov random fields (GMRFs) for modeling the prior. Then, with the prior in hand, I will proceed to the main part of the talk, which focuses on the problem of sampling from the posterior density function (or simply the posterior). I will assume that both the measurement error and prior variances are unknown and place hyper-prior probability density functions on these scalar parameters. The resulting hierarchical Bayesian posterior is non-Gaussian, but lends itself well to the use of the Gibbs sampler. I will present this Gibbs sampler and then discuss its drawbacks in terms of algorithmic performance. I will then present two alternative MCMC methods, both of which make use of marginalization, and which have better performance characteristics than the Gibbs sampler.
"MCMC Methods for Hierarchical Models in Bayesian Inverse Problems"
4 November 2016
12:00 pm to 1:00 pm
"MCMC Methods for Hierarchical Models in Bayesian Inverse Problems"
Johnathan Bardsley
University of Montana