Events
Suzanne M. O’Regan, North Carolina A&T State University, Early warning signals of critical transitions: new theoretical directions
Cox 306Anticipating abrupt changes in ecosystem state is key for ecosystem management and preservation. Detailed knowledge of ecological mechanisms behind a critical transition is often difficult to attain, and the theory of resilience - assessment of the ability of a system to withstand disturbances - provides a pathway to circumvent this problem. Loss of system resilience…
Jo-Ann Cohen, NC State, Diversity Statements
SAS 4201Target Audience: Third, Fourth, and Fifth Years
Darij Grinberg, University of Minnesota, Multiline queues and their generating functions
SAS 4201Multiline queues were introduced by Ferrari and Matrin as a tool for understanding the steady state of the Totally Asymmetric Simple Exclusion Process (TASEP) on a ring. Since then, they have attracted independent interest as combinatorial objects. A queue can be described as a transformation of words by a combinatorial rule (related to the Lascoux-Schützenberger action of the symmetric group). A…
Helen Cleaves, NC State, Global Sensitivity Analysis for function-valued random parameter
SAS 4201We address global sensitivity analysis for models with high-dimensional inputs and function-valued (functional) outputs. Variance-based global sensitivity approaches based on Sobol' indices have been proven useful in a wide range of outputs. However, Sobol' indices can be challenging to compute for computationally intensive models with a large number of parameters. We propose derivative based global…
Adam Lowrance, Vassar College, Gordian distance and spectral sequences in Khovanov homology
The Gordian distance between two knots is the fewest number of crossing changes necessary to transform one knot into the other. Khovanov homology is a categorification of the Jones polynomial that comes equipped with several spectral sequences. In this talk, we show that the page at which some of these spectral sequences collapse gives a…
Nicolas Buchler, NC State, Evolution and interaction of oscillators in a noisy cell
Cox 306Gene expression is a biochemical process driven by the chance collisions of molecules, which can result in strong stochastic signatures and cell-to-cell variability in gene network dynamics (e.g. oscillation). Biological oscillators co-exist in the same cell and can interact directly or indirectly through shared resources. Our lab uses modeling and experiments to understand how these…
Min Hoon Kim, Korea Institute for Advanced Study, A family of freely sliced good boundary links
The still open topological surgery conjecture for 4-manifolds is equivalent to the statement that all good boundary links are freely slice. In this talk, I will show that every good boundary link with a pair of derivative links on a Seifert surface satisfying a homotopically trivial plus assumption is freely slice. This subsumes all previously…
Khai Nguyen, NC State, Recent Results on Compactness Estimates for Nonlinear PDEs
SAS 4201This talk will be devoted to a fundamental question on the compactness of sets of solutions. The key concept in this study is the Kolmogorov epsilon-entropy which is the logarithm of the minimum number of elements in an epsilon-covering of a given (totally bounded) set. I will use this concept to provide a sharp estimate…
Ben Freedman, NC State, Nonlinear differential equations subject to generalized boundary conditions
In this talk, we analyze nonlinear differential equations subject to generalized boundary conditions. More specifically, I will provide a framework from which we can provide conditions, which are straightforward to check, for the solvability of a large number of nonlinear scalar boundary value problems. I will begin by giving the general strategy which involves a reformulation of our…
SIAM Student Chapter Industry Series: Steven Hamilton, Oak Ridge National Laboratory, The Department of Energy Exascale Computing Project
This will be the first seminar in the SIAM Industry series, which is focused on presenting information about research opportunities in business, industry, and government jobs. Speakers will discuss their career paths and speak on projects they have worked on at their current industrial institution. The DOE Exascale Computing Project (ECP), a collaborative effort between…
Colloquium Tea
SAS 4104Benedetto Piccoli, Rutgers University, Control Problems for Measure Evolutions
SAS 1102Classical control theory deals with controlled ODEs and PDEs. An interesting setting, where both ODE and PDE control appear naturally, is that of multi-agent systems and crowd dynamics. Recently, control problems involving measure-valued solutions attracted a lot of attention as a tool to deal with such systems. The measure can serve as the probabilistic representation…
SIAM Student Chapter Internship Panel: Ariel Nikas, Zack Morrow, Mallory McMahon, Ryan Vogt, and Dan Reich, NC State
SAS 4201This seminar will be an informal panel of some of our fellow graduate students speaking on their experiences with applying to and participating in internships in business, industry, and government. This will be an opportunity for graduate students to hear testimonies about the benefits and types of problems that are addressed when doing an internship…
Rekha Biswal, Laval University, Affine structure and tableaux models for E_7 crystals
SAS 4201A Kirillov-Reshetikhin(KR) module is a certain finite dimensional U_q'(\mathfrak{g}) module that is determined by its Drinfeld polynomials. KR modules are an important class of modules for quantum groups with many applications to Mathematical physics. KR modules are conjectured to have many nice properties, one of which is the existence of a crystal basis. In this talk, we will give a…
Ryan Vogt, NC State, A MIPDECO Formulation for Robust Electromagnetic Cloaking
SAS 4201We propose a Mixed Integer Partial Differential Equation Constrained Optimization (MIPDECO) formulation of the topological optimization for electromagnetic cloaking. Our formulation introduces binary variables to indicate the presence/absence of metamaterial at a given location within the cloaking device. The cloaking device is discretized on a 20x20 and 40x40 domain of squared material locations, and has two to…
Jianfeng Lu, Duke University, Solving large-scale leading eigenvalue problem
SAS 4201The leading eigenvalue problems arise in many applications. When the dimension of the matrix is super huge, such as for applications in quantum many-body problems, conventional algorithms become impractical due to computational and memory complexity. In this talk, we will describe some recent works on new algorithms for the leading eigenvalue problems based on randomized and coordinate-wise methods (joint work with…