Research Day 2025: Friday, October 31

Welcome and Short (10-minute) Presentations
11:30-12:35

Lunch Break: Pizza and Mingling
12:35-1:15

Second Set of Short Presentations
1:15-2:15

Break
2:15-2:35

Third Set of Short Presentations
2:35-3:25

Reception for Colloquium
3:30-4:00

Colloquium
4:00-5:00

Dr. Mirjeta Pasha

Assistant Professor
Department of Mathematics

Title: From Deterministic Modeling to Bayesian Inference: A Computational Journey through Large-Scale Inverse Problems

Abstract: Rapidly-growing fields such as data science, uncertainty quantification, and machine learning rely on fast and accurate methods for inverse problems. Three emerging challenges on obtaining relevant solutions to large-scale and data-intensive inverse problems are ill-posedness of the problem, large dimensionality of the parameters, and the complexity of the model constraints. Tackling the immediate challenges that arise from growing model complexities (spatiotemporal measurements) and data-intensive studies (large-scale and high-dimensional measurements collected as time-series), state-of-the-art methods can easily exceed their limits of applicability. In this talk we discuss efficient methods for computing solutions to dynamic inverse problems, where both the quantities of interest and the forward operator may change at different time instances.

We consider large-scale ill-posed problems that are made more challenging by their dynamic nature and, possibly, by the limited amount of available data per measurement step. In the first part of the talk, to remedy these difficulties, we apply efficient regularization methods that enforce simultaneous regularization in space and time (such as edge enhancement at each time instant and proximity at consecutive time instants) and achieve this with low computational cost and enhanced accuracy. In the remainder of the talk, we focus on designing spatio-temporal Bayesian Besov priors for computing the MAP estimate and quantifying the uncertainties in large-scale and dynamic inverse problems. Numerical examples from a wide range of applications, such as biomedical applications, tomographic reconstruction, image deblurring, and multichannel dynamic tomography are used to illustrate the effectiveness of the described approaches.