Neutrinos are very weakly interacting particles that have unique properties that allow indirect measurements that cannot be realized with any other particle or field. I will give an introduction to neutrino physics and describe two inverse problems with neutrinos. This is based on joint work with Gunther Uhlmann. https://ncsu.zoom.us/j/94955574178?pwd=cFpRUlZScXRmdGFscE5FZEhIb1NWdz09 Meeting ID: 949 5557 4178 Passcode: 301451
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…
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,…
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)…
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…
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,…
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…
A panel of experienced instructors will share their thoughts on writing effective exams for undergraduate courses. The panel is timed to precede the first round of midterms for lower-division courses. The panelists will take questions from the moderators and audience. Moderators: Kylan Schatz, Ashley Tharp (NC State) Zoom Meeting: Link
I will provide an overview of how to apply for different graduate research fellowships. These can be very valuable as they provide lots of time to get research done, which can help get better academic or non-academic jobs. I will focus on the NSF Graduate Research Fellowship. Note that the NSF GRFP is limited to…
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…
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,…
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…
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…
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…
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.…
I will describe---using anecdotes, excerpts from textbooks, and thought experiments---various approaches to creating a narrative voice when teaching a calculus class. Zoom Meeting: Link
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…
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.…
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…
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…
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…
Lascoux polynomials are K-theoretic analogues of the key polynomials. They both have combinatorial formulas involving tableaux: reverse set-valued tableaux (RSVT) rule for Lascoux polynomials and reverse semistandard Young tableaux (RSSYT) rule for key polynomials. Besides, key polynomials have a simple algorithmic model in terms of Kohnert diagrams, which are in bijection with RSSYT. Ross and…
Classification is a fundamental task in data science and machine learning, and in the past ten years there have been significant improvements on classification tasks (e.g. via deep learning). However, recently there have been a number of works demonstrating that these improved algorithms can be “fooled” using specially constructed adversarial examples. In turn, there has been increased…
For any metric space, the metric gives deep insight into the space such as geometry and topology of the space. Rather than directly studying a specific space, one may wish to study a sequence of spaces with nice properties and then show that desired properties hold in the limit. To study such a sequence of…
We consider sensitivity analysis of Bayesian inverse problems with respect to modeling uncertainties. To this end, we consider sensitivity analysis of the information gain, as measured by the Kullback-Leibler divergence from the posterior to the prior. This choice provides a principled approach that leverages key structures within the Bayesian inverse problem. Also, the information gain…
Mean field games (MFGs) study strategic decision-making in large populations where individual players interact via specific mean-field quantities. They have recently gained enormous popularity as powerful research tools with vast applications. For example, the Nash equilibrium of MFGs forms a pair of PDEs, which connects and extends variational optimal transport problems. This talk will present…
Jointly in person and virtually on Zoom. SAS 2225 for in-person participation. The Zoom link is sent out to the Algebra and Combinatorics mailing list, please contact Corey Jones at cmjones6@ncsu.edu to be added. Speaker’s webpage: https://www.wm.edu/as/mathematics/faculty-directory/russoniello_n.php
In this talk, I want to present some of the ideas behind the theory of embodied cognition, which is a theory that tries to understand how our teaching and learning experiences are affected by our gestures. I will share how research is done in Math Education and my experience collaborating on a project lead by…