Machine learning and statistical methods for physical systems

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Abstract/Contents

Abstract
Physical systems often exhibit highly complex, non-linear behaviors, making their characterization without a profound understanding of underlying dynamics a challenging endeavor. In this presentation, I will explore several methodologies for integrating valuable prior knowledge into machine learning-based and statistical methods, aimed at predicting physical system behaviors and bolstering the control of engineering systems. The talk will be divided into three main parts. In the first part, I will present several deep-learning-based interpolation methods for estimating nearshore bathymetry with sparse measurements. By applying deep learning-based models from a Bayesian perspective, we provide uncertainty quantification for the underlying bathymetry profile and compare our predictions with those from Gaussian Process Regression (GPR). Results show that our approach provides more accurate posterior estimates, particularly when encountering patterns with sharp gradients, such as those found around sandbars and submerged objects. In the second part, I will introduce a novel framework, namely physics-based Parameterized Neural Ordinary Differential Equations, for predicting laser ignition inside a rocket combustor. A 0D reacting flow model is combined with neural ordinary differential equations to deliver accurate solutions, even with limited training samples, that adhere to physical constraints. We validate our physics-based PNODE using solution snapshots of high-fidelity Computational Fluid Dynamics (CFD) simulations, demonstrating its capability to accurately learn complex combustion dynamics with high-dimensional parameters of laser ignition. In the third part, we consider the use of a periodic Martingale Model for Forecast Evolution (MMFE) to integrate weather forecasts into decision-making processes for energy system controls. We demonstrate that, when combined with a linear state space model, our periodic MMFE yields computationally tractable Markov Decision Processes (MDPs) with low-dimensional state variables. We provide algorithms for the maximum likelihood estimation of model parameters for our periodic MMFE and showcase the corresponding asymptotic convergence. Furthermore, we validate the generative power of our framework for weather forecast errors by calibrating our periodic MMFE using real data collected from hourly commercial weather forecasts.

Description

Type of resource text
Form electronic resource; remote; computer; online resource
Extent 1 online resource.
Place California
Place [Stanford, California]
Publisher [Stanford University]
Copyright date 2023; ©2023
Publication date 2023; 2023
Issuance monographic
Language English

Creators/Contributors

Author Qian, Yizhou
Degree supervisor Darve, Eric
Thesis advisor Darve, Eric
Thesis advisor Glynn, Peter W
Thesis advisor Kitanidis, P. K. (Peter K.)
Degree committee member Glynn, Peter W
Degree committee member Kitanidis, P. K. (Peter K.)
Associated with Stanford University, School of Engineering
Associated with Stanford University, Institute for Computational and Mathematical Engineering

Subjects

Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Yizhou Qian.
Note Submitted to the Institute for Computational and Mathematical Engineering.
Thesis Thesis Ph.D. Stanford University 2023.
Location https://purl.stanford.edu/yx222yd2245

Access conditions

Copyright
© 2023 by Yizhou Qian
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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