Seminars and Colloquia by Series

Series: Other Talks
Saturday, February 20, 2016 - 09:00 , Location: Mathematics and Science Center, Emory University , various , various , Organizer: Annette Rohrs
The Georgia Scientific Computing Symposium (GSCS) is a forum for professors, postdocs, graduate students and other researchers in Georgia to meet in an informal setting, to exchange ideas, and to highlight local scientific computing research. The symposium has been held every year since 2009 and is open to the entire research community. This year, the symposium will be held at Emory University. The format of the day-long symposium is a set of invited presentations, poster sessions and a poster blitz, and plenty of time to network with other attendees. Invited speakers include: Michele Benzi, Mathematics and Computer Science, Emory University; Steven Hamilton, Radiation Transport Group, Oak Ridge National Laboratory; Alexandra Smirnova, Mathematics and Statistics, Georgia State University; Phanish Suryanarayana, School of Civil & Environmental Engineering, Georgia Institute of Technology; Molei Tao, Mathematics, Georgia Institute of Technology; Qing Zhang, Mathematics, University of Georgia. Poster sessions will be held during the lunch and afternoon breaks.
Series: Other Talks
Thursday, February 18, 2016 - 13:30 , Location: John and Joyce Caddell Building Flex Space , S. Rutt Bridges , Georgia Tech, Geosciences, Alumni , Organizer: Prasad Tetali
Series: Other Talks
Wednesday, February 17, 2016 - 13:05 , Location: Skiles 006 , Max Fathi , Department of Mathematics, UC Berkeley , Organizer: Prasad Tetali
In this talk, I will explain how the gradient flow structure of reversible Markov chains (that was discovered by Maas and Mielke independently in 2011) and the Sandier-Serfaty approach to convergence of gradient flows can be combined to study scaling limits for interacting particle systems on lattices. The exposition will be focused on the case of the simple exclusion process on the discrete torus. Joint work with Marielle Simon (INRIA Lille). 
Series: Other Talks
Monday, February 15, 2016 - 14:00 , Location: Skiles 270 , John Dever , Ga. Tech , Organizer: John Dever
Topics: local Hausdorff dimension, local Hausdorff measure, diffusion on compact metric spaces, prospective further research.
Series: Other Talks
Saturday, January 16, 2016 - 09:00 , Location: Skiles 006 , Karim Adiprasito, June Huh, Eric Katz , Various , Organizer: Josephine Yu
A one day workshop on the proof of Rota's conjecture on the log concavity of coefficients of the characteristic polynomial of a matroid.   Please register: 
Series: Other Talks
Monday, November 30, 2015 - 15:05 , Location: Howey L3 , Kenneth Showalter , West Virginia University , Organizer:

Hosted by Roman Grigoriev, School of Physics

We have studied large, heterogeneous populations of discrete chemical oscillators (~100,000) to characterize two different types of density-dependent transitions to synchronized behavior, a gradual Kuramoto synchronization and a sudden quorum sensing synchronization. We also describe the formation of phase clusters, where each cluster has the same frequency but is phase shifted with respect to other clusters, giving rise to a global signal that is more complex than that of the individual oscillators. Finally, we describe experimental and modeling studies of chimera states and their relation to other synchronization states in populations of coupled chemical oscillators.
Series: Other Talks
Monday, November 23, 2015 - 11:05 , Location: Skiles 006 , Sergey Bobkov , University of Minnesota, Minneapolis , Organizer: Prasad Tetali
We will discuss an extension of the entropy power inequality in terms of the Renyi entropy to sums of independent random vectors (with densities). Joint work with G. Chistyakov.
Series: Other Talks
Sunday, November 15, 2015 - 09:00 , Location: Skiles 006 , Noga Alon , Tel Aviv University and IAS, Princeton , Organizer: Xingxing Yu

Second featured lecture in the Atlanta Lecture Series in Combinatorics and Graph Theory mini-conference

The study of graphs with high girth and high chromatic number had a profound influence on the history of Combinatrics and Graph Theory, and led to the development of sophisticated methods involving tools from probability, topology, number theory, algebra and combinatorics. I will discuss the topic focusing on a recent new explicit construction of graphs (and hypergraphs) of high girth and high chromatic number, in joint work with Kostochka, Reiniger, West and Zhu.
Series: Other Talks
Saturday, November 14, 2015 - 13:00 , Location: Skiles 006 , Noga Alon , Tel Aviv University and IAS, Princeton , Organizer: Xingxing Yu

First featured lecture in the Atlanta Lecture Series in Combinatorics and Graph Theory mini-conference

I will describe several old and new applications of topological and algebraic methods in the derivation of combinatorial results. In all of them the proofs provide no efficient solutions for the corresponding algorithmic problems.
Series: Other Talks
Monday, October 26, 2015 - 13:30 , Location: Skiles 168 , Raphael Hauser , Mathematical Institute, University of Oxford , Organizer: Heinrich Matzinger
We propose a term structure power price model that, in contrast to widely accepted no-arbitrage based approaches, accounts for the non-storable nature of power. It belongs to a class of equilibrium game theoretic models with players divided into producers and consumers. The consumers' goal is to maximize a mean-variance utility function subject to satisfying an inelastic demand of their own clients (e.g households, businesses etc.) to whom they sell the power. The producers, who own a portfolio of power plants each defined by a running fuel (e.g. gas, coal, oil...) and physical characteristics (e.g. efficiency, capacity, ramp up/down times...), similarly, seek to maximize a mean-variance utility function consisting of power, fuel, and emission prices subject to production constraints. Our goal is to determine the term structure of the power price at which production matches consumption. We show that in such a setting the equilibrium price exists and discuss the conditions for its uniqueness. The model is then extended to account for transaction costs and liquidity considerations in actual trading. Our numerical simulations examine the properties of the term structure and its dependence on various model parameters. We then further extend the model to account for the startup costs of power plants. In contrast to other approaches presented in the literature, we incorporate the startup costs in a mathematically rigorous manner without relying on ad hoc heuristics. Through numerical simulations applied to the entire UK power grid, we demonstrate that the inclusion of startup costs is necessary for the modeling of electricity prices in realistic power systems. Numerical results show that startup costs make electricity prices very spiky. In a final refinement of the model, we include a grid operator responsible for managing the grid. Numerical simulations demonstrate that robust decision making of the grid operator can significantly decrease the number and severity of spikes in the electricity price and improve the reliability of the power grid.