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Department of Mathematics

Upcoming Events

Branwen Purdy at her stall during OMSI meet-a-scientist day.

Branwen Purdy prepares hands-on activities for kids at the OMSI Meet-A-Scientist Day in Portland, to share hands-on learning experiences about her research in topological data analysis.

Join us for these events hosted by the Department of Mathematics, including colloquia, seminars, graduate student defenses and outreach, or of interest to Mathematicians hosted by other groups on campus.

Access our archive of events

Math Matters: Multi-* Modeling, Analysis and Simulation

Memorial Union Horizon Room
External

Speaker: Małgorzata Peszyńska

Abstract: We describe our research on multi-scale multi-physics systems modeled with multi-valued operators: a complex blend of beauty, truth and utility of computational and applied mathematics inspired by real life applications. We travel from nano- to pore- to lab- and field scale of porous media filled with fluids and materials in multiple phases to discover and predict the response of these systems to the external changing world. Along the way we show the indispensable role of abstract elegant mathematics to innovate, analyze the accuracy and efficiency of the algorithms and models, and to serve as a universal language. We also show how essential it is to build the bridges within the local Oregon State University community and external partners enabling interdisciplinary collaborations to help our students to "choose the complex and challenging over the easy and simple."Register at https://oregonstate.qualtrics.com/jfe/form/SV_emMiMlaHgrRRtSm Read more.

Improving the representation of snowpack processes and distribution with model-data fusion

STAG 112
Applied Mathematics and Computation Seminar

Speaker: Mark Raleigh

ABSTRACT:Seasonal snowpack is the largest areal component of the global cryosphere and is a major source of summer water supply in regions such as western North America and High Mountain Asia. The amount of water stored in winter snowpack (snow water equivalent, SWE) can vary significantly in space and time due to heterogeneous climate and landscape processes that influence snow accumulation and melt processes. This critical water resource is under monitored due to sparse ground-based observational networks, and a lack of satellite remote sensing system that can measure SWE across all global snow types and conditions. However, emerging remote sensing techniques and new capabilities with model-data fusion offer the potential to improve our understanding and prediction of snow water resources. In this seminar, I will highlight how we can improve representation of SWE and related snowpack processes through the integration of numerical snowpack models and observations using data… Read more.

The Association for Women in Math - 2024 Int'l Women in Math Day

Kelley Engineering Building 1003
Conference

Speaker: Kathryn Nyman

About International Women in Math DayInternational Women in Math Day was formally conceived in 2018 at the World Meeting for Women in Mathematics, (WM)². The date, May 12th, was chosen as a tribute to Dr. Maryam Mirzakhani - the first Iranian, and the first woman to win a Fields Medal for her groundbreaking work on the dynamics and geometry of Riemann surfaces. Dr. Mirzakhani tragically passed away in 2017, at just 40 years old. The purpose of International Women in Math Day is to celebrate women and their contributions to mathematics, and to promote inclusivity within the broad fields of science and mathematicsAWM at OSU - Why do we do this every year?The Association for Women in Mathematics at Oregon State University aims to build a welcoming and inclusive mathematical community which promotes gender equity in the field, among other Diversity, Equity, and Inclusivity (DEI) values. Throughout this event, we choose to highlight the work of local women mathematicians and encourage… Read more.

On the 'resolving power' of complete interpolating sequences

Kidder 237
Analysis Seminar

Speaker: Adel Faridani

Square-integrable functions whose Fourier transforms have compact support in the interval [-pi, pi] can be recovered from their samples on a set of points called a complete interpolating sequence (CIS). A CIS is a minimal set in the sense that it has minimal density and recovery fails if a single point is removed from the CIS. The integers are the best-known example of a CIS, leading to uniform sampling and the classical Sampling Theorem. We investigate whether all CISs are 'created equal', or if some CISs can 'resolve' larger spaces of bandlimited functions than others. Read more.

A semiclassical approach to Kerov's CLT

KIDD 236
Probability and Data Science Seminar

Speaker: Alexander Moll

Abstract. Spatially-periodic solutions v(x,t) of the Hopf equation (also known as the inviscid Burgers equation) in one spatial dimension admit an explicit classical hierarchy of conserved quantities. In 2016, Dubrovin gave a remarkable new characterization of Schur polynomials as eigenfunctions of an integrable quantization of these conserved quantities. In joint work with Robert Chang (Reed College), we show that a special property of Dubrovin's quantization - its "Wick-remainder decomposition'' - combined with the theory of coherent states enables a streamlined semiclassical proof of Kerov's central limit theorem for Plancherel measures. In this talk, I will present Dubrovin's quantization from a combinatorial point of view, then illustrate the key ideas in the proof of our semiclassical CLT in the case of a single quantum harmonic oscillator. Read more.

Lonseth Lecture: Inverse Problems and Harry Potter's Cloak

Construction & Engineering Hall at the LaSells Stewart Center
Lonseth Lecture

Speaker: Gunther Uhlmann

Abstract: Inverse problems arise in all fields of science and technology where causes for a desired or observed effect are to be determined. By solving an inverse problem is in fact how we obtain a large part of our information about the world. An example is human vision: from the measurements of scattered light that reaches our retinas, our brains construct a detailed three-dimensional map of the world around us. In the first part of the talk we will describe several inverse problems arising in different contexts.In the second part of the lecture we will discuss invisibility. Can we make objects invisible? This has been a subject of human fascination for millennia in Greek mythology, movies, science fiction, etc including the legend of Perseus versus Medusa and the more recent Star Trek and Harry Potter. In the last 20 years or so there have been several scientific proposals to achieve invisibility. We will describe in a non-technical fashion a simple and powerful proposal, the so-… Read more.

Journey to the Center of the Earth

Colloquium

Speaker: Gunther Uhlmann

We will consider the inverse problem of determining the sound speed or index of refraction of a medium by measuring the travel times of waves going through the medium. This problem arises in global seismology in an attempt to determine the inner structure of the Earth by measuring travel times of earthquakes. It also has several applications in optics and medical imaging among others.The problem can be recast as a geometric problem: Can one determine the Riemannian metric of a Riemannian manifold with boundary by measuring the distance function between boundary points? This is the boundary rigidity problem. We will survey some of the known results about this problem.No previous knowledge of differential geometry will be assumed. Read more.

Investigating Gender Bias in the OpenStax Ebook, College Algebra 2e: An Addition to an Ongoing Conversation

Virtual
M.S. Defense

Speaker: Kaitlynn Spiker

The purpose of this thesis is to investigate gender bias in the OpenStax online textbook, College Algebra 2e. First, I provide a literature review that details how textbooks have historically been gender-biased, and how this is particularly disheartening for students in science, technology, engineering, and mathematics (STEM) fields. I then summarize research that illustrates the importance of representation in STEM fields. To study whether bias was present in the College Algebra textbook, I created a database of all the applied problems in the textbook and coded them based on different criteria. Next, I aggregated the data into summary tables for each category and created proportions for each of the categories. Finally, I used confidence intervals and Fisher’s Exact Test to compare the different proportions. I did not find evidence of gender bias in the problems, but I did find a lack of representation in the historical figures mentioned in the textbook. This shows improvements from… Read more.

Digital Twins for Time Dependent Problems

STAG 112
Applied Mathematics and Computation Seminar

Speaker: Juan Restrepo

ABSTRACT: A digital twin is a set of algorithms that connect the virtual world to the physical worl in a fully bi-directional way: for example, a predictive digital twin will use physics models, machine learned models, constraints as well as observations to make forecasts. A digital twin used as a controller would yield a virtual prescription, taking into account observations, that prescribes changes in the real world aimed at obtaining a certain desired real world outcome. I will describe ongoing work on developing a digital twin that will become central to an artificial intelligence framework for large scale electric grid resilience via adaptation. BIO: Juan M. Restrepo is a Distinguished Member of the R&D staff and the section head of the mathematics in computation section at Oak Ridge National Laboratory. His research concerns foundational aspects of machine learning and the development of new artificial intelligence algorithms for science. He is a Fellow of the Society of… Read more.