Academics

Hybrid projection methods for solution decomposition in large-scale Bayesian inverse problems

Time:August 19, 2025

Venue:C654, Shuangqing Complex Building

Organizer:Lingyun Qiu

Speaker:Jiahua Jiang

Jiahua Jiang

University of Birmingham

Jiahua Jiang received a BS degree in Applied Mathematics from the University of Science and Technology of China in 2013, and a PhD in Engineering and Applied Science from the University of Massachusetts Dartmouth in 2018. After her PhD degree, Jiahua did postdoctoral research at Virginia Tech. She subsequentially worked at ShanghaiTech University (assistant professor, 2020–2021). She joined the University of Birmingham as an assistant professor in 2022.

Organizer

邱凌云

Time

Tuesday, 9:00-10:00 am

August 19, 2025

Venue

C654, Shuangqing Complex Building

Abstract

We develop hybrid projection methods for computing solutions to large-scale inverse problems, where the solution represents a sum of different stochastic components. Such scenarios arise in many imaging applications (e.g., anomaly detection in atmospheric emissions tomography) where the reconstructed solution can be represented as a combination of two or more components and each component contains different smoothness or stochastic properties. In a deterministic inversion or inverse modeling framework, these assumptions correspond to different regularization terms for each solution in the sum. Although various prior assumptions can be included in our framework, we focus on the scenario where the solution is a sum of a sparse solution and a smooth solution. For computing solution estimates, we develop hybrid projection methods for solution decomposition that are based on a combined flexible and generalized Golub–Kahan process. This approach integrates techniques from the generalized Golub–Kahan bidiagonalization and the flexible Krylov methods. The benefits of the proposed methods are that the decomposition of the solution can be done iteratively, and the regularization terms and regularization parameters are adaptively chosen at each iteration. Numerical results from photoacoustic tomography and atmospheric inverse modeling demonstrate the potential for these methods to be used for anomaly detection.

DATEAugust 16, 2025
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