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  • Oct
    29

    Appl Math: Pedram Hassanzadeh on "Integrating the Spectral Analyses of Neural Networks and Nonlinear Physics for Explainability, Generalizability, and Stability"

    McCormick-Engineering Sciences and Applied Mathematics (ESAM)

    11:15 AM M416, Technological Institute

    EVENT DETAILS

    Title: Integrating the Spectral Analyses of Neural Networks and Nonlinear Physics for Explainability, Generalizability, and Stability

    Speaker: Pedram Hassanzadeh, The University of Chicago

    Abstract: In recent years, there has been substantial interest in using deep neural networks (NNs) to improve the modeling and prediction of complex, multiscale, nonlinear dynamical systems such as turbulent flows and Earth’s climate. In idealized settings, there has been some progress for a wide range of applications from data-driven spatio-temporal forecasting to long-term emulation to subgrid-scale modeling. However, to make these approaches practical and operational, i.e., scalable to real-world problems, a number of major questions and challenges need to be addressed. These include 1) instabilities and the emergence of unphysical behavior, e.g., due to how errors amplify through NNs, 2) learning in the small-data regime, 3) interpretability based on physics, and 4) out-of-distribution generalization (e.g., extrapolation to different parameters, forcings, and regimes) which is essential for applications to non-stationary systems such as a changing climate. While some progress has been made in addressing (1)-(4), e.g., doing transfer learning for generalization, these approaches have been often ad-hoc, as currently there is no rigorous framework to analyze deep NNs and develop systematic and general solutions to (1)-(4). In this talk, I will discuss some of the approaches to address (1)-(4), for example, once we identify spectral bias as the cause of instabilities in state-of-the-art weather models like Pangu-weather, GraphCast, and FourCastNet. Then I will introduce a new framework that combines the spectral (Fourier) analyses of NNs and nonlinear physics, and leverages recent advances in theory and applications of deep learning, to move toward rigorous analysis of deep NNs for applications involving dynamical systems. For example, this approach can guide and explain transfer learning and pruning in such applications. I will use examples from turbulence modeling and weather/climate prediction to discuss these methods and ideas.

    Zoom: https://northwestern.zoom.us/j/99466696080

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    TIME Tuesday, October 29, 2024 at 11:15 AM - 12:15 PM

    LOCATION M416, Technological Institute    map it

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    CONTACT Ted Shaeffer    ted.shaeffer@northwestern.edu EMAIL

    CALENDAR McCormick-Engineering Sciences and Applied Mathematics (ESAM)

  • Sep
    8

    Welcome & Breakfast for New McCormick PhD Students

    McCormick School of Engineering and Applied Science

    9:00 AM LR2 & Tech East Plaza, Technological Institute

    EVENT DETAILS

    TIME Monday, September 8, 2025 at 9:00 AM - 10:00 AM

    LOCATION LR2 & Tech East Plaza, Technological Institute    map it

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    CONTACT Andi Joppie    andi.joppie@northwestern.edu EMAIL

    CALENDAR McCormick School of Engineering and Applied Science

  • Sep
    12

    New Undergraduate Fall 2025 Registration

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Friday, September 12, 2025

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    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar

  • Sep
    15

    Welcome & Luncheon for New Full-time Graduate Students

    McCormick School of Engineering and Applied Science

    11:00 AM Ryan Auditorium & Tech East Plaza, Technological Institute

    EVENT DETAILS

    TIME Monday, September 15, 2025 at 11:00 AM - 12:30 PM

    LOCATION Ryan Auditorium & Tech East Plaza, Technological Institute    map it

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    CONTACT Andi Joppie    andi.joppie@northwestern.edu EMAIL

    CALENDAR McCormick School of Engineering and Applied Science

  • Sep
    16

    Fall Classes Begin. Change of Registration (Drop/Add) Late registration for returning students begins

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Tuesday, September 16, 2025

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    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar