## Seminars

## Nonlinear Waves Seminar - Justin Cole

Oct. 29, 2019

Justin Cole Department of Applied Mathematics, University of Colorado Boulder Soliton Dynamics in the Korteweg-de Vries Equation with Nonzero Boundary Conditions Inspired by recent experiments, the Korteweg-de Vries equation with nonzero Dirichlet boundary conditions is considered. Two types of boundary data are examined: step up (which generates a rarefaction wave)...

## Applied Math Colloquium - Maria Kazachenko

Oct. 25, 2019

Maria Kazachenko Department of Astrophysics and Planetary Science (National Solar Observatory), University of Colorado Boulder Data-driven Models of the Solar Corona Magnetic Fields: Present and Future The most violent space weather events, eruptive solar flares and coronal mass ejections, are driven by the release of free magnetic energy stored in...

## Applied Math Colloquium - Steve Sain

Oct. 11, 2019

Steve Sain Jupiter Intelligence, Boulder CO Data Science @ Jupiter In 2017, the US faced over $300 billion in loses from hurricanes, severe weather, flooding, drought, fire, etc. These national catastrophes are placing an increasing burden on the public and are projected to worsen in the future. Jupiter Intelligence provides...

## Nonlinear Waves Seminar - Patrick Weidman

Oct. 8, 2019

Patrick Weidman Department of Mechanical Engineering, University of Colorado Boulder Steady flow of one uniformly rotating fluid layer above another immiscible uniformly rotating fluid layer. The steady laminar flow of two immiscible, uniformly rotating fluid layers is studied and exact similarity solutions of the axisymmetric Navier-Stokes equations in cylindrical polar...

## Applied Math Colloquium - Andreas Kloeckner

Oct. 4, 2019

Andreas Kloeckner Department of Computer Science, University of Illinois Fast Algorithms for the Evaluation of Layer and Volume Potentials I will present new, asymptotically fast algorithms with high-order error bounds for the evaluation of layer and volume potentials in two and three dimensions. The efficient evaluation of both types of...

## Complex/Dynamical Systems Seminar - Bernd Kraukopf and Hinka Osinga

Oct. 3, 2019

Bernd Krauskopf and Hinka Osinga Department of Mathematics, University of Auckland Hetero-dimensional Cycles and Blenders Recent theoretical work on partially hyperbolic systems by Bonatti and Diaz (and others) has shown that chaotic dynamics may occur C1-robustly in diffeomorphisms of dimension at least three. More specifically, the existence of hetero-dimensional cycles...

## Math Bio Seminar - Erin Ellefsen

Oct. 1, 2019

Erin Ellefsen Department of Applied Mathematics University of Colorado Boulder Efficiently finding steady states of nonlocal territorial models in Ecology There are certain populations of animals that tend to move in social groups. We investigate territory development of these social groups by studying a system of non-local continuum equations. However,...

## Stats, Optimization, and Machine Learning Seminar - Yury Makarychev

Oct. 1, 2019

Yury Makarychev Toyota Technological Institute at Chicago (TTIC) Performance of Johnson-Lindenstrauss Transform for k-Means and k-Medians Clustering Consider an instance of Euclidean k-means or k-medians clustering. We show that the cost of the optimal solution is preserved up to a factor of (1+ε) under a projection onto a random O(log(k/ε)/ε^2)-dimensional...

## Applied Math Colloquium - Rebecca Morrison

Sept. 27, 2019

Rebecca Morrison Department of Computer Science, University of Colorado Boulder Representing model error in reduced models of interacting systems In many applications of interacting systems, we are only interested in the dynamic behavior of a subset of all possible active species. For example, this is true in combustion models (many...

## Joint APPM/MATH Colloquium - Catherine Sulem

Sept. 24, 2019

Catherine Sulem Department of Mathematics, University of Toronto Bloch theory and spectral gaps for linearized water waves We consider the movement of a free surface of a two-dimensional fluid over a variable bottom. We assume that the bottom has a periodic prole and we study the water wave system linearized...