Events
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Math Doesn’t Bug Me
11 West Jones Street, Raleigh, NC, 27601, United StatesDiscover the beauty of mathematics and its wide applicability in everyday life. Enjoy math games and poster presentations, and interact with NCSU mathematicians
Leonardo Mihalcea, Chern-Schwartz-MacPherson classes for Schubert cells: geometry and representation theory
SAS 4201A compact manifold has a tangent bundle, and a natural question is to find a replacement for the Chern classes of the tangent bundle, in the case when the space is singular. The Chern-Schwartz-MacPherson (CSM) classes are homology classes which ``behave like" the Chern classes of the tangent bundle, and are determined by a functoriality…
Shu-Cherng Fang, NC State ISE, Linear Reformulation of Polynomial Discrete Programming for Fast Computation
SAS 4201Optimization models involving a polynomial objective function and multiple polynomial constraints with discrete variables are often encountered in engineering, management and systems. Treating the non-convex cross-product terms is the key. State-of- the-art methods usually convert such a problem into a 0-1 mixed integer linear programming problem, and, then adopt a branch-and- bound scheme to find…
Erdal Imamoglu, NC State, Algorithms for Solving Linear Differential Equations with Rational Function Coefficients
SAS 4201We present two algorithms for computing hypergeometric solutions of a second order linear differential equation with rational function coefficients. Our first algorithm uses quotients of formal solutions, modular reduction, Hensel lifting, and rational reconstruction. Our second algorithm first tries to simplify the input differential equation using integral bases and then uses quotients of formal solutions.
Juanita Pinzon-Caicedo, NC State, Crunched Charms: A Short Intro to Knot Theory
Knot theory is the subarea of topology that studies math- ematical knots or different ways of placing a circle inside 3- dimensional space. Proving that two knots are distinct (or equivalent) is the main problem knot theorists deal with. In the talk, we will discuss methods used to distinguish knots. For a simple introduction click…
Amy Ward, University of Southern California, Scheduling in a Many-Server, Multi-Class System: The Impact of the Customer Patience Distribution
Withers 232AThe study of scheduling problems has a long history in the academic literature. However, many classic models used to study scheduling problems do not incorporate customer impatience. Furthermore, many of the ones that do assume the time a customer is willing to wait for service is exponentially distributed. The issue is that that assumption can…
Hoon Hong and Lorena Bociu
SAS 4201Math Department Picnic
Pullen Park, Shelter #4 RaleighThe department provides hamburgers, hot dogs, veggie burgers, buns, fixings, utensils, etc. We will send out an invitation and sign up sheet for volunteering to help-out or bring drinks, desserts, side dishes, etc. in the first or second week of September.
Heekyoung Hahn, Duke University, Langlands’ beyond endoscopy proposal and related questions on algebraic groups and combinatorics
SAS 4201Langlands' beyond endoscopy proposal for establishing functoriality motivates the study of irreducible subgroups of $\mathrm{GL}_n$ that stabilize a line in a given representation of $\mathrm{GL}_n$. Such subgroups are said to be detected by the representation. In this talk we present a family of results when the subgroup is a classical group in the important special…
Sung Ha Kang, Georgia Tech, Variational image processing and computational challenges
SAS 4201Starting with an introduction to variational/PDE based image processing, this talk will focus on new developments of fast algorithms for higher order variational imaging models. For example, recent developments of fast algorithms, based on operator splitting, augmented Lagrangian, and alternating minimization, enabled us to revisit some of the variational image models, such as Euler's Elastica…
Chris Tralie, Duke University, From Musical Rhythms To Vibrating Vocal Folds: Geometric (Quasi)Periodicity Quantification in Multimedia Time Series
SAS 4201A large variety of multimedia data inference problems require analysis of repeated structures. In audio, for instance, the rhythm, or ``pulse'' of the music, occurs in a periodic pattern, and understanding this pattern is an important preprocessing step in music information retrieval. In medical video analysis, there is interest in determining heart pulse rate in…
Kristen Boyle, NC State, On derivations of Leibniz algebras
Leibniz algebras are a generalization of Lie algebras. In this talk I will discuss some results on characteristic ideals, which are analogs of known results from Lie algebra. I will use these results to prove that the radical of a Leibniz algebra is a characteristic ideal. We will also explore the derivation algebra of cyclic…
Garrett Nieddu, Montclair State University, Rare Events in Stochastic Population Models
Cox 306Noise can play a critical role in a wide array of physical and biological dynamical systems. The noise may be internal or external to the system. Internal noise is intrinsic to the system itself, and in stochastic population models, arises due to the random interactions of discrete agents in the system. On the other hand,…
Joshua Hallam, Wake Forest University, Whitney duals of graded partially ordered sets
SAS 4201To each graded poset one can associate two sequences of numbers; the Whitney numbers of the first kind and the Whitney numbers of the second kind. One sequence keeps track of the Möbius function at each rank level and other keeps track of the number of elements at each rank level. We say two posets…
Slava Krushkal, University of Virginia, Flow and Yamada polynomials, planar triangulations, and TQFT
SAS 1102In the 1960s Tutte observed that the value of the chromatic polynomial of planar triangulations at (golden ratio +1) obeys a number of remarkable properties. In this talk I will explain how TQFT gives rise to a conceptual framework for studying planar triangulations. I will discuss several extensions of Tutte's results and applications to the…
Murthy Gudatti, NC State, Efficient Forward and Inverse Algorithms for Guided Wave Inversion
SAS 4201Guided waves are widely utilized in the fields of nondestructive testing and geophysical inversion, to estimate the medium properties through inversion of the dispersion curves. In this talk, we present improved methodologies for computing both dispersion curves and their derivatives, the two main ingredients of guided wave inversion. Specifically, a novel discretization approach based on Pade Approximants, named complex-length finite element…
The Storm Next Time: Hurricanes and Climate Change
Genome Sciences Building, G100 Auditorium at UNC Chapel Hill" The recent tragedies of Hurricanes Harvey and Irma, together with earlier extreme events such as Hurricanes Katrina and Sandy, has raised the question whether the apparent increasing severity of such events can be attributed to the human influence on greenhouse gas warming. Dr. Emanuel will review the growing consensus that the incidence of the…
Sercan Yildiz, SAMSI,Polynomial Optimization with Sums-of-Squares Interpolants
Sums-of-squares certificates define a hierarchy of relaxations for polynomial optimization problems which are parametrized with the degree of the polynomials in the sums-of-squares representation. Each level of the hierarchy generates a lower bound on the true optimal value, which can be computed in polynomial time via semidefinite programming, and these lower bounds converge to the…