Upcoming MAMS Seminar Series

Spring 2024

3/6/2024, Wed. 4-5 pm in Sears 439
Speaker: Dr. Weihong Guo
Title: Nonnegative and Nonlocal Sparse Tensor Factorization Based Hyperspectral Image Super-Resolution
Abstract: Hyperspectral image (HSI) super-resolution refers to enhancing the spatial resolution of a 3-D image with many spectral bands (slices). It is a seriously ill-posed problem when the low-resolution (LR) HSI is the only input. It is better solved by fusing the LR HSI with a high-resolution (HR)  multispectral image (MSI) for a 3-D image with both high spectral and spatial resolution. In this talk, we propose a novel nonnegative and nonlocal 4-D tensor dictionary learning-based HSI super-resolution model using group-block sparsity. By grouping similar 3-D image cubes into clusters and then conduct super-resolution cluster by cluster using 4-D tensor structure, we not only preserve the structure but also achieve sparsity within the cluster due to the collection of similar cubes. We use 4-D tensor Tucker decomposition and impose nonnegative constraints on the dictionaries and group-block sparsity. Numerous experiments demonstrate that the proposed model outperforms many state-of-the-art HSI super-resolution methods.

1/31/2024, Wed. 4-5 pm in Sears 439
Speaker: Dr. Anuj Abhishek
Title: An operator learning framework for an inverse problem in Electrical Impedance Tomography
Abstract: Neural network architectures such as Fourier Neural Operators (FNO) and Deep Operator Networks (Deep-O-Net) have been shown to be fairly useful in approximating an operator between two function spaces. In this talk, we will briefly review an inverse problem that arises in Electrical Impedance tomography as well as review such operator learning network architectures. We will then see how we might use similar network architectures to learn (or, approximate) a map that takes in as its input the Dirichlet to Neumann operator and outputs the corresponding conductivity function. This is based on an unfinished ongoing work with my collaborator, Thilo Strauss (Xi’an Jiaotong-Liverpool University).

Spring 2024

3/6/2024, Wed. 2:15-3:15 pm in Olin 314
Speaker: Dr. David Singer
Title: Confocal Families of Conics in the Hyperbolic Plane
Abstract: Conics in the hyperbolic plane exhibit much more variety than those in the Euclidean plane. Depending on the author, they have been classified as occurring in nine, eleven, or twelve forms. I will describe a classification of confocal families of conics, where a focus can be understood as a source of rays from a point in the plane, an ideal point, or an ultra-ideal point. The presentation will be on an expository level; previous experience with hyperbolic geometry will not be vital for understanding the talk (I hope!)