Seminars and Colloquiums
for 2010-2011
Week of September 27, 2010
Speaker:
Professor Vasileios Maroulas, Monday
Mr. Jacob Ogle, Monday
Mr. Nick Gewecke, Tuesday
Dr. Ross Cressman, Tuesday
Mr. Keith Penrod, Wednesday
Professor Joan Lind, Wednesday
Mr. Zhen Guan, Thursday
Professor Mohammad Ghomi, Georgia Tech, Friday
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. Fernando Schwartz.
Monday, September 27
PROBABILITY SEMINAR
TIME: 10:10 – 11:00 am
ROOM: Temple 303
SPEAKER: Professor Vasileios Maroulas
TITLE: "Improved particle filters and an application in the problem of multi-target tracking-Part II"
ABSTRACT: A novel approach for improving particle filters is presented. The suggested approach is based on Girsanov's change of measure theorem for stochastic differential equations. Girsanov's theorem is used to design a Markov Chain Monte Carlo step which is appended to the particle filter and aims to bring the particle filter samples closer to the observations. The proposed approach is applied in the problem of multi-target tracking for both linear and nonlinear observation models. Also, a simple Metropolis Monte Carlo algorithm for tackling the target-observation association problem is presented. The numerical results show that the suggested approach can improve significantly the performance of a particle filter. The talk will be based on joint works with P. Stinis.
ALGEBRA SEMINAR
TIME: 3:35 – 4:25 pm
ROOM: AC 113A
SPEAKER: Jacob Ogle
TITLE: When is $k[f]$ the ring of constants of a derivation? (Part 3)
ABSTRACT: We will begin with a brief introduction to derivations. Next, we consider $k[f]$, a subdomain of a polynomial ring over a field $k$, and consider some necessary conditions for
$k[f]$ to be the field of constants of some derivation. When these conditions are fulfilled, we will demonstrate a construction of the desired derivation.
Tuesday, September 28
MATH BIOLOGY SEMINAR
TIME: 9:30 – 10:20 a.m.
ROOM: NIMBioS Classroom
SPEAKER: Nick Gewecke, Math Department, UTK
TITLE: "Controlling the spread of plant invasions: the importance of nascent foci"
NIMBIOS SEMINAR
TIME: 3:30 pm
ROOM: 403, Blount Hall, 1534 White Ave.
SPEAKER: Dr. Ross Cressman, Department of Mathematics, Wilfrid Laurier University
TITLE: "Game experiments on cooperation through punishment and/or reward"
ABSTRACT: We report results from two different experiments that test the effects of punishment and/or reward schemes on the cooperative behavior of players in repeated Prisoner's Dilemma (PD) and Public Goods (PGG) games. In the two-player PD experiment, each player has the third option of punishing his opponent at a cost to himself (i.e. the player chooses between cooperation (C), defection (D) and costly punishment (P)) in each round based on payoffs observed and strategies used in previous rounds. In the four-player PGG experiment, an outside agency rewards, punishes, or rewards and punishes players between rounds based on their contributions to the public good. Subjects for both game experiments were university students in Beijing. For our PD experiment, costly punishment does not increase the average level of cooperation compared to the control experiment where this option is not available. This result contrasts with several similar experiments conducted in Western societies. In our PGG control experiment (i.e. the standard repeated PGG without reward or punishment), the average contribution levels to the public good match closely those found in the same experiment conducted in Boston. On the other hand, in contrast to these experiments in Boston that exhibited little difference in contribution level when players rewarded and/or punished each other between rounds, our PGG experiment shows that our combined reward and punishment scheme is the most effective in increasing contributions, followed by punishment on its own and that reward on its own has little effect on contributions. These results are discussed in relation to cultural differences in attitudes to a player's reputation and to institutional incentive schemes designed to increase the cooperative behavior of its members. They are also discussed in relation to the Nash equilibrium structure of the corresponding single-stage games.
*Join us for refreshments in the NIMBioS Lobby at 3 pm.
Wednesday, September 29
TOPOLOGY SEMINAR
TIME: 12:20 – 1:10 pm
ROOM: BEC 202
SPEAKER: Keith Penrod
TITLE: "Infinite Product Spaces"
ANALYSIS SEMINAR
TIME: 3:35 – 4:25 p.m.
ROOM: AC 113
SPEAKER: Professor Joan Lind
TITLE: "A look at SLE and its significance"
ABSTRACT: Since its introduction 10 years ago, Schramm Loewner Evolution (SLE) has garnered much attention, and two of the researchers in this area, Wendelin Werner and Stas Smirnov, have won Fields Medals for their work in this field. We will take an introductory look at SLE and discuss its significance.
Thursday, September 30
APPLIED/COMPUTATIONAL MATH SEMINAR
TIME: 5:10 – 6:00 p.m.
ROOM: AC 113
SPEAKER: Zhen Guan, Math Department, UTK,
TITLE: "An Unconditionally Energy Stable Spectral Method for Phase Separation
Models Derived from a Nonlocal Energy"
ABSTRACT: We present an unconditionally energy stable spectral method for a family of phase separation models. The free energy of these models include both local and nonlocal terms. We prove that both the local and global terms can be rewritten as the sum of convex and concave functionals. Our scheme is semi-implicit in time, where the contribution from the convex energy is treated implicitly and that from the concave part is treated explicitly. Based on this splitting we prove both the unconditional solvability and unconditional stability of our scheme. We present some numerical examples to demonstrate the feasibility of the scheme.
Friday, October 1
COLLOQUIUM
TIME: 3:35 – 4:25 pm
ROOM: HBB 102
SPEAKER: Professor Mohammad Ghomi, Georgia Tech
TITLE: "The space of unbounded convex bodies"
ABSTRACT: We show that every unbounded convex body in Euclidean space, whose boundary is a topological hyperplane, may be canonically deformed to a half-space, through a continuous family of unbounded convex bodies. In particular it follows that the space of unbounded positively curved hypersurfaces of Euclidean space is not contractible, which settles a question of Harold Rosenberg. These results are obtained with respect to a natural topology on the space of unbounded convex bodies, which we devise to ensure the continuity of the total curvature function during our deformations.
Join us for refreshments available at 3:15 in AC113.
Past notices:
Seminars from 2009-2010 academic year
Seminars from 2008-2009 academic year
Seminars from 2007-2008 academic year
Seminars from 2006-2007 academic year