Seminars and Colloquia by Series

Feature Based Fusion of Multimodal Data for Object Classification

Series
Applied and Computational Mathematics Seminar
Time
Monday, October 4, 2010 - 13:00 for 1 hour (actually 50 minutes)
Location
Skiles 002
Speaker
Michael Burkhart – Gatech, Math
The over-abundance of remotely sensed data has resulted inthe realization that we do not have nor could ever acquire asufficient number of highly trained image analysts to parse theavailable data.  Automated techniques are needed to perform low levelfunctions, identifying scenarios of importance from the availabledata, so that analysts may be reserved for higher level interpretativeroles. Data fusion has been an important topic in intelligence sincethe mid-1980s and continues to be a necessary concept in thedevelopment of these automated low-level functions. We propose anapproach to multimodal data fusion to combine images of varyingspatial and spectral resolutions with digital elevation models.Furthermore, our objective is to perform this fusion at the imagefeature level, specifically utilizing Gabor filters because of theirresemblance to the human visual system.

The effects of small noise random perturbation for some problems without unique solutions.

Series
Probability Working Seminar
Time
Friday, October 1, 2010 - 15:05 for 1.5 hours (actually 80 minutes)
Location
Skiles 249
Speaker
Sergio Almada – School of Math, Georgia Tech
We consider the small noise perturbation (in the Ito sense) of a one dimensional ODE. We study the case in which the ODE has not unique solution, but the SDE does. A particular setting of this sort is studied and the properties of the solution are obtained when the noise level vanishes. We relate this to give an example of a 1-dimensional transport equation without uniqueness of weak solution. We show how by a suitable random noise perturbation, the stochastic equation is well posed and study what the limit is when the noise level tends to zero.

Heegaard-Floer Theory by examples

Series
Geometry Topology Working Seminar
Time
Friday, October 1, 2010 - 14:00 for 2 hours
Location
Skiles 171
Speaker
John Etnyre and/or Amey Kaloti – Ga Tech
In this talk we will give an introduction of Heegaard-Floer theory through examples. By exploring several explicit examples we hope to show that various aspects of the definitions that seem complicated, really aren't too bad and it really is possible to work with these fairly abstract things. While this is technically a continuation of last weeks talk, we will review enough material so that this talk should be self contained.

A Stochastic Differential game for the inhomogeneous infinity-Laplace equation

Series
Stochastics Seminar
Time
Thursday, September 30, 2010 - 15:05 for 1 hour (actually 50 minutes)
Location
Skiles 002
Speaker
Amarjit Budhiraja – University of North Carolina at Chapel Hill
A two-player zero-sum stochastic differential game, defined in terms of an m-dimensional state process that is driven by a one-dimensional Brownian motion, played until the state exits the domain, is studied.The players controls enter in a diffusion coefficient and in an unbounded drift coefficient of the state process. We show that the game has value, and characterize the value function as the unique viscosity solution of an inhomogeneous infinity Laplace equation.Joint work with R. Atar.

Introduction to infinite matroids

Series
Graph Theory Seminar
Time
Thursday, September 30, 2010 - 12:05 for 1 hour (actually 50 minutes)
Location
Skiles 114
Speaker
Luke Postle – Math, GT
Rota asked in the 1960's how one might construct an axiom system for infinite matroids. Among the many suggested answers were the B-matroids of Higgs. In 1978, Oxley proved that any infinite matroid system with the notions of duality and minors must be equivalent to B-matroids. He also provided a simpler mixed basis-independence axiom system for B-matroids, as opposed to the complicated closure system developed by Higgs. In this talk, we examine a recent paper of Bruhn et al that gives independence, basis, circuit, rank, and closure axiom systems for B-matroids. We will also discuss some open problems for infinite matroids.

Analysis in constructions of low discrepancy sets

Series
Analysis Seminar
Time
Wednesday, September 29, 2010 - 16:30 for 1 hour (actually 50 minutes)
Location
Skiles 269
Speaker
Dmitriy Bilyk – University of South Carolina
Low discrepancy point distributions play an important role in many applications that require numerical integration. The methods of harmonic analysis are often used to produce new or de-randomize known probabilistic constructions. We discuss some recent results in this direction.

Applications of diffusion models to sequential decision making

Series
Research Horizons Seminar
Time
Wednesday, September 29, 2010 - 12:00 for 1 hour (actually 50 minutes)
Location
Skiles 171
Speaker
Yuri Bakhtin – School of Mathematics - Georgia Institute of Technology

Please Note: Hosts: Yao Li and Ricardo Restrepo

I will consider mathematical models of decision making based on dynamics in the neighborhood of unstable equilibria and involving random perturbations due to small noise. I will report results on the vanishing noise limit for these systems, providing precise predictions about the statistics of decision making times and sequences of unstable equilibria visited by the process. Mathematically, the results are based on the analysis of random Poincare maps in the neighborhood of each equilibrium point. I will discuss applications to neuroscience and psychology along with some experimental data.

Network Models for Infectious Disease Dynamics

Series
Mathematical Biology Seminar
Time
Wednesday, September 29, 2010 - 11:00 for 1 hour (actually 50 minutes)
Location
Skiles 169
Speaker
Shweta Bansal – Center for Infectious Disease Dynamics, Penn State
Many infectious agents spread via close contact between infected and susceptible individuals. The nature and structure of interactions among individuals is thus of fundamental importance to the spread of infectious disease. Heterogeneities among host interactions can be modeled with contact networks, and analyzed using tools of percolation theory. Thus far, the field of contact network epidemiology has largely been focused on the impact of network structure on the progression of disease epidemics. In this talk, we introduce network models which incorporate feedback of the disease spread on network structure, and explore how this feedback limits the potential for future outbreaks. This has implications for seasonal diseases such as influenza, and supports the need for more adaptive public health policies in response to disease dynamics.

Analytification is the Limit of All Tropicalizations

Series
Tropical Geometry Seminar
Time
Wednesday, September 29, 2010 - 10:05 for 1 hour (actually 50 minutes)
Location
Skiles 114
Speaker
Ye Luo – Georgia Tech
We introduce extended tropicalizations for closed subvarieties of toric varieties and show that the analytification of a quasprojective variety over a nonarchimedean field is naturally homeomorphic to the inverse limit of the tropicalizations of its quasiprojective embeddings. This talk is based on a paper of Sam Pyane with the same title.

Turbulence: a walk on the wild side

Series
PDE Seminar
Time
Tuesday, September 28, 2010 - 15:00 for 1 hour (actually 50 minutes)
Location
Skiles 255
Speaker
Prof. Predrag Cvitanović – Physics, Georgia Institute of Technology –
In the world of moderate Reynolds number, everyday turbulence of fluids flowing across planes and down pipes a velvet revolution is taking place. Experiments are almost as detailed as the numerical simulations, DNS is yielding exact numerical solutions that one dared not dream about a decade ago, and dynamical systems visualization of turbulent fluid's state space geometry is unexpectedly elegant. We shall take you on a tour of this newly breached, hitherto inaccessible territory. Mastery of fluid mechanics is no prerequisite, and perhaps a hindrance: the talk is aimed at anyone who had ever wondered why - if no cloud is ever seen twice - we know a cloud when we see one? And how do we turn that into mathematics? (Joint work with J. F. Gibson)

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