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Department of Mathematics

Applied Mathematics and Computation Seminars

Methane bubbles frozen in the ice of Lake Baikal

The AMC seminar is devoted to general topics in applied mathematics and computation. We welcome an interdisciplinary audience and speakers: faculty, researchers, and graduate students from mathematics, geosciences, computer science, engineering, atmospheric sciences, and other disciplines, to attend and present research talks in their fields as well as reaching across multiple fields. Both technical, tutorial, and expository presentations are welcome.

Attendees are encouraged to join the mailing list by sending an email to the organizer (M. Peszynska).

Students attending regularly are encouraged to sign up for (an appropriate section of) seminar credit under MTH 607. Non-OSU participants from outside academe are also encouraged to write an email to the organizers and provide their names and affiliation.

See below for upcoming seminars or access the seminar archive.

Organizers

Malgorzata Peszynska and Ralph E. Showalter.

Timing

Meetings are Fridays at noon.

Data-Driven Kernel Matrix Computations: Geometric Analysis and Scalable Algorithms

STAG 112

Speaker: Cai Difeng

ABSTRACT: Dense kernel matrices arise in a broad range of disciplines, such as potential theory, molecular biology, statistical machine learning, etc. To reduce the computational cost, low-rank or hierarchical low-rank techniques are often used to construct an economical approximation to the original matrix. In this talk, we consider general kernel matrices associated with possibly high dimensional data. We perform analysis to provide a straightforward geometric interpretation that answers a central question: what kind of subset is preferable for skeleton low-rank approximations. Based on the theoretical findings, we present scalable and robust algorithms for black-box dense kernel matrix computations. The efficiency and robustness will be demonstrated through experiments for various datasets, kernels, and dimensions, including benchmark comparison to the state-of-the-art packages for N-body simulations.BIO: Difeng Cai received his BS in math from University of Science and Technology… Read more.

Sink or Soar: the interplay between buoyant bubbles and sinking sediments inenergizing turbulence near the ice-ocean boundary

STAG 112

Speaker: Megan Wengrove

ABSTRACT: At the terminus of tidewater glaciers an interplay of connected processes result in the melt of ice. From both field and laboratory observations, it has been suggested that both bubbles and sediments could be important yet neglected contributors to ice melt at the submarine tidewater glacier terminus. In the laboratory it has been shown that as glacier ice melts, air trapped in pores inside of the ice is released creating flow transpiration at the boundary and buoyant bubble rise at the ice-ocean interface, leading to increased melt (Wengrove et al.,2023). Additionally, during separate laboratory experiments, sediments entrained in the subglacial discharge plume are shown to increase the entrainment of warm ocean water toward the ice leading to higher melt rates (McConnochie andCenedese, 2023). In July 2024, we made the first ever video observations of both bubbles rising and sediments mixing and falling from a stationary-bolted platform to an Alaskan tidewater glacier… Read more.