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Differential Equations Seminar: Paul Manns, TU Dortmund, Germany, On total variation regularization for PDE-constrained optimization with integer controls

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We study the effect of total variation regularization on PDE-constrained optimization problems, where the control input functions may only attain finitely many integer values. The regularization helps to avoid undesirable effects such as chattering behavior. In particular, the weak-* compactness of the feasible set in the space of functions of bounded variation allows to derive…

Numerical Analysis Seminar: Brendan Keith, Brown University, Adaptive sampling for constrained optimization under uncertainty

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Stochastic optimization problems with deterministic constraints commonly appear in machine learning, finance, and engineering applications. This talk presents a new adaptive solution strategy for this important class of problems. The aim is to decrease the computational cost while maintaining an optimal convergence rate. The guiding principle is to adjust the batch size (or sample size)…

SIAM Bootcamp Series #2 – MATLAB

Poe Hall 211

We are excited to announce that SIAM is hosting another bootcamp: a two-part series that introduces you to MATLAB. Both graduate and undergrads are welcome, so please spread the word! You’re encouraged to have Matlab installed, which is free for NCSU students. For a detailed instruction on how to download and install Matlab to your computer,…

Biomath Seminar: Justen Geddes, NC State, Modeling and Data Analysis of Postural Orthostatic Tachycardia Syndrome

Cox 306

Postural Orthostatic Tachycardia Syndrome (POTS) is characterized by an increase of heart rate of 30 beats per minute (40 bpm in patients aged 12-19 years) upon a postural change, combined with the presence of orthostatic symptoms. In addition to these criteria, recent studies have shown that POTS patients exhibit large low frequency ~0.1 Hz heart…

Geometry and Topology Seminar: Yaoye Hong, NC State, ECE Department, Programmable morphologies of kirigami sheets and applications.

SAS 4201

Shape-shifting materials from 2D thin sheets to 3D shapes are attractive for broad applications in programmable machines and robots, functional biomedical devices, and four-dimensional printing. Kirigami, the art of paper cutting, has recently emerged as a promising approach for shape morphing structures and materials due to its new properties such as auxeticity, stretchability, conformability, multistability, and optical chirality. In this talk,…

Differential Equations/Nonlinear Analysis Seminar: Michael Malisoff, LSU, Event-Triggered Control Using a Positive Systems Approach

SAS 4201

Control systems are a class of dynamical systems that contain forcing terms. When control systems are used in engineering applications, the forcing terms can represent forces that can be applied to the systems. Then the feedback control problem consists of finding formulas for the forcing terms, which are functions that can depend on the state…

Applied Math Graduate Student Seminar: Introductory and Organizational Meeting

SAS 4201

If you are interested in learning more about applied math research from your fellow students, or you want a friendly and constructive environment to practice presenting your own applied math research, AMGSS is for you! This is an informational and sign-up meeting, so come to learn more about AMGSS and/or to sign up to present…

Numerical Analysis Seminar: Jamie Haddock, Harvey Mudd College, Connections between Iterative Methods for Linear Systems and Consensus Dynamics on Networks

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There is a well-established linear algebraic lens for studying consensus dynamics on networks, which has yielded significant theoretical results in areas like distributed computing, modeling of opinion dynamics, and ranking methods.  Recently, strong connections have been made between problems of consensus dynamics on networks and classical iterative methods in numerical linear algebra.  This talk will…

SIAM Bootcamp Series #2 – MATLAB

Poe Hall 211

We are excited to announce that SIAM is hosting another bootcamp: a two-part series that introduces you to MATLAB. Both graduate and undergrads are welcome, so please spread the word! You’re encouraged to have Matlab installed, which is free for NCSU students. For a detailed instruction on how to download and install Matlab to your computer,…

Biomath Seminar: Zixuan Cang, NC State, Spatiotemporal analysis of single-cell and spatial genomics data

Cox 306

The emerging single-cell and spatial genomics techniques allow us to elucidate the governing rules of multicellular systems with unprecedented resolution and depth. These datasets are often high-dimensional, complex, and heterogeneous. Mathematical tools are needed to extract biological insights from such data. In this talk, we will discuss several mathematical and machine learning methods for exploring…

Geometry and Topology Seminar: Ian Zemke, Princeton, Bordered aspects of the Heegaard Floer surgery formulas

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In this talk, we will discuss bordered aspects of the Heegaard Floer surgery formulas of  Ozsvath--Szabo and Ozsvath--Manolescu. In particular, we will explain how their theories naturally define bordered invariants for manifolds with toroidal boundary components. Time permitting, we will discuss applications of the theory. One application is a proof of the equivalence of lattice…

Differential Equations/Nonlinear Analysis Seminar: Maria Teresa Chiri, Queen’s University, Controlling the spread of invasive biological species

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We consider a controlled reaction-diffusion equation, modeling the spreading of an invasive population. Our goal is to derive a simpler model, describing the controlled evolution of a contaminated set. We first analyze the optimal control of 1-dimensional traveling wave profiles. Using Stokes’ formula, explicit solutions are obtained, which in some cases require measure-valued optimal controls.…

Applied Math Graduate Student Seminar: William Anderson, NC State, Efficient computation of reduced-order nonlinear solutions for PDEs

SAS 4201

In this talk we develop a method for efficient computation of reduced-order nonlinear solutions (RONS). RONS is a framework to create reduced-order models for time-dependent partial differential equations (PDEs) where the reduced-order solution has nonlinear dependence on time-varying parameters. With RONS we obtain an explicit set of ordinary differential equations (ODEs) to evolve the parameters.…

Pure Math Grad Student Seminar: Emily McGovern, NC State, Module categories for \text{Tilt}(SL_{2k+1}) from \tilde{A}_{n-1}-buildings

SAS 2235

We show that the category of vector bundles over the vertices of a locally finite \tilde{A}_{n-1} building \Delta, Vec(\Delta), has the structure of a Tilt(SL_{2k+1}) module category. This module category is the q-analogue of the Tilt(SL_{2k+1}) action on vector bundles over the sl_n weight lattice. Our construction of the Tilt(SL_{2k+1}) action on Vec(\Delta) extends to…

Numerical Analysis Seminar: Themis Sapsis, MIT, Likelihood-weighted active learning with application to Bayesian optimization, uncertainty quantification, and decision making in high dimensions

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Analysis of physical and engineering systems is characterized by unique computational challenges associated with high dimensionality of parameter spaces, large cost of simulations or experiments, as well as existence of uncertainty. For a wide range of these problems the goal is to either quantify uncertainty and compute risk for critical events, optimize parameters or control…

Biomath Seminar: Dr. Archana Timsina and Evan Curcio, NC State, Identifiability and optimal control analysis of HIV infection and opioid addiction model / How do tension ratios determine morphometry in physical models of notochord cell packing?

Cox 306

Dr. Timsina's Talk: Identifiability and optimal control analysis of HIV infection and opioid addiction model. Abstract: In a compartmental model of HIV infection and opioid addiction, dynamics such as equilibria, basic reproduction number, and invasion numbers are presented. Identifiability and estimation of the parameters of the model are highlighted. Moreover, the effect of four distinct controls such…

Geometry and Topology Seminar: Jiahua Zou, Brown University, Free boundary minimal surfaces in the Euclidean three-ball close to boundary

SAS 4201

I will talk about the new construction of genus-zero free boundary minimal surfaces embedded in the unit ball in the Euclidean three-space which are compact and lie arbitrarily close to the boundary unit sphere with an arbitrarily large number of connected boundary components. The construction is by PDE gluing methods and the surfaces are desingularizations…