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  • Apr
    15

    Appl Math: Dan Wilson on "Phase-Amplitude-Based Techniques for Control and Analysis of Strongly Perturbed Limit Cycle Oscillators"

    McCormick-Engineering Sciences and Applied Mathematics (ESAM)

    11:15 AM M416, Technological Institute

    EVENT DETAILS

    Title: Phase-Amplitude-Based Techniques for Control and Analysis of Strongly Perturbed Limit Cycle Oscillators

    Speaker: Dan Wilson, University of Tennessee, Knoxville

    Abstract: While phase-based reduction techniques have a rich history in the analysis and control of oscillatory dynamical systems, the overwhelming majority of theoretical analysis in this field has been performed in the weakly perturbed limit. Comparatively very little is understood about limit cycle oscillators in response to strong and/or long-lasting perturbations, mostly due to the lack of viable reduction strategies that are valid when considering strong perturbations. In this presentation, I will discuss the use of isostable coordinates, which characterize level sets of the slowest decaying eigenmodes of the Koopman operator in conjunction with phase-based techniques to yield analytically tractable reduced order models that are valid in the strongly perturbed regime. Applications involving phase resetting of circadian rhythms following rapid travel across multiple time zones illustrate the utility of these new methods in situations where standard, phase-only techniques fail. I will also discuss related work motivated by experimental and detailed computational studies finding that coupled circadian oscillators with decreased levels of synchronization are able to more rapidly adjust to changes in circadian time. Theoretical analysis reveals the dynamics of mean-field coupled oscillators can be considered in the context of a supercritical Hopf bifurcation, ultimately providing an explanation for the fundamental relationship between synchronization and phase resetting efficiency. In the context of jet-lag recovery strategies, further analysis reveals that transient desynchronization facilitates phase resetting when the relaxation rate of the population limit cycle is sufficiently slow relative to the natural frequency of the population oscillation.

    Zoom: https://northwestern.zoom.us/j/91324444590

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    TIME Tuesday, April 15, 2025 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)

  • Jun
    15

    2024-2025 Commencement Ceremony

    University Academic Calendar

    All Day

    EVENT DETAILSmore info

    TIME Sunday, June 15, 2025

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

    CALENDAR University Academic Calendar

  • Jun
    16

    Northwestern Engineering PhD Hooding and Master's Degree Recognition Ceremony

    McCormick School of Engineering and Applied Science

    9:00 AM 2705 Ashland Ave

    EVENT DETAILS

    TIME Monday, June 16, 2025 at 9:00 AM - 11:00 AM

    LOCATION 2705 Ashland Ave   

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    CONTACT Northwestern Engineering Events    northwestern-engineering-events@northwestern.edu EMAIL

    CALENDAR McCormick School of Engineering and Applied Science

  • Jun
    16

    Northwestern Engineering Undergraduate Convocation

    McCormick School of Engineering and Applied Science

    2:00 PM 2705 Ashland Ave

    EVENT DETAILSmore info

    TIME Monday, June 16, 2025 at 2:00 PM - 4:00 PM

    LOCATION 2705 Ashland Ave   

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    CONTACT Northwestern Engineering Events    northwestern-engineering-events@northwestern.edu EMAIL

    CALENDAR McCormick School of Engineering and Applied Science

  • Jun
    23

    Summer classes begin

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Monday, June 23, 2025

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

    CALENDAR University Academic Calendar

  • Sep
    16

    Fall 2025 Classes Begin

    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