Seminars and Colloquiums
for the week of February 23, 2009
Speakers:
Mr. Michael Lawton, Monday
Dr. Jin Xu, Assistant Computational Scientist/Physicist, MCS, Argonne Laboratory, Tuesday
Assistant Professor Remus Nicoara, Wednesday
Professor Jerzy Dydak, Wednesday
Professor Leonid Mytnik, Israel Institute of Technology, Technion. , Thursday
Dr. Amy Szczepanski, Thursday
Dr. Yi Sun, Courant Institute, NYU, Friday
Monday, February 23
MATH ECOLOGY SEMINAR
TIME: 11:15 – 12:05 p.m.
ROOM: Dabney 575
SPEAKER: Mr. Michael Lawton
TITLE: “Birds and Social Networks”
Tuesday, February 24
MATHEMATICS COLLOQUIUM
TIME: 3:35 – 4:25 p.m.
ROOM: HBB 102
SPEAKER: Dr. Jin Xu, Assistant Computational Scientist/Physicist, MCS, Argonne Laboratory
TITLE: "Scientific Computing with High Order Methods "
ABSTRACT: Scientific computing now becomes more and more important in science and engineering. The essential to its success is the efficient numerical methods. In this talk, researches on developing efficient numerical methods, especially high order methods, to solve various partial differential equations will be presented. These methods, as well as scalable parallel models, have been applied to different fields, such as fluid dynamics, beam dynamics and electromagnetics, etc. High order methods have demonstrated their power and advantages than other methods. Both traditional and newly emerged high order methods will be discussed. Physical models, simulation results and challenges in these fields will be presented and discussed. Developing more efficient numerical methods has great value in academia and applying them to current and new scientific area has great prospect.
Wednesday, February 25
ANALYSIS SEMINAR
TIME: 3:35 – 4:25 p.m.
ROOM: AC 113A
SPEAKER: Professor Remus Nicoara
TITLE: “Continuous deformations of commuting squares and subfactors, I"
ABSTRACT: In the early 80's V. Jones introduced the theory of subfactors, as a Galois theory for inclusions of von Neumann algebras. A subfactor can be viewed as a group-like object that encodes the symmetries of a quantum physical or mathematical situation. In this first talk I will give a general introduction to subfactors and their invariants. In the next talks I will present a deformation theory for commuting squares, squares of *-algebras which arise as invariants and construction data for subfactors.
TOPOLOGY SEMINAR
TIME: 3:35 – 4:25 p.m.
ROOM: AC 113
SPEAKER: Professor Jerzy Dydak
TITLE: “A combinatorial approach to coarse geometry II"
ABSTRACT: This is joint work with M.Cencelj, A.Vavpetic, and Z.Virk. We introduce the anti-barycentric subdivision A(K) of simplicial complexes K. This leads to the concept of a coarse simplicial complex and allows to introduce coarse structures and uniform structures in a manner much simpler than the classical definitions.
Thursday, February 26
Probability Seminar
Time: 12:40-1:30
Place: HBB 132
Speaker: Professor Leonid Mytnik, Israel Institute of Technology, Technion.
Title: Pathwise uniqueness for stochastic heat equations with H\"{o}lder
continuous coefficients
JUNIOR COLLOQUIUM
TIME: 3:40 – 4:25 p.m.
ROOM: HBB 102
SPEAKER: Dr. Amy Szczepanski
TITLE: “Untangled Threads: Mathematical Knitting"
ABSTRACT: Not only can mathematics be used to design knitting patterns, but knitting patterns can be designed that describe mathematics. One example of this is the relationship between knitted cable patterns and the mathematics of the braid
group. In this talk, I'll introduce a bit about both knitted cables and the braid group, describe some relationships between them, and demonstrate how elements of the mathematical group can be represented in knitting. Additionally, I'll talk a little bit about how similar ideas can be applied to design knitted representations of some of the classic sorting algorithms from computer science.
This work is based, in part, on "(K)Not Cables, Braids" by Sarah-Marie Belcastro, Amy Szczepanski, and Carolyn Yackel, from the book Making Mathematics with Needlework.
Friday, February 27
MATHEMATICS COLLOQUIUM
TIME: 3:35 – 4:25 p.m.
ROOM: HBB 102
SPEAKER: Dr. Yi Sun, Courant Institute, NYU
TITLE: “Network dynamics of Hodgkin-Huxley neurons”
ABSTRACT: The reliability and predictability of neuronal network dynamics is a central question in neuroscience. We present a numerical analysis of the dynamics of all-to-all pulsed-coupled Hodgkin-Huxley (HH) neuronal networks. Since this is a non-smooth dynamical system, we propose a pseudo-Lyapunov exponent (PLE) that captures the long-time predictability of HH neuronal networks. The PLE can capture very well the dynamical regimes of the network. Furthermore, we present an efficient library-based numerical method for simulating HH neuronal networks. Our pre-computed high resolution data library can allow us to avoid resolving the spikes in detail and to use large numerical time steps for evolving the HH neuron equations. By using the library-based method, we can evolve the HH networks using time steps one order of magnitude larger than the typical time steps used for resolving the trajectories without the library, while achieving comparable resolution in statistical quantifications of the network activity. Moreover, our large time steps using the library method can overcome the stability requirement of standard ODE methods for the original dynamics.
If you are interested in giving or arranging a talk for one of our seminars or colloquiums, please review our calendar.
If you have questions, or a date you would like to confirm, please contact Dr. Steve Wise.
Week of:
Past notices:
Seminars from 2007-2008 academic year
Seminars from 2006-2007 academic year