All Seminars
| Title: The Spread of Rabies in Raccoons: Numerical Simulations of a Spatial Diffusion Model |
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| Defense: Honors Thesis |
| Speaker: Joshua Keller of Emory University |
| Contact: Alessandro Veneziani, ale@mathcs.emory.edu |
| Date: 2011-04-07 at 10:30AM |
| Venue: N215 |
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| Abstract: |
| Title: Spatial Optimization of 4-Poster Feeders for Tick-Borne Disease Management |
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| Defense: Honors Thesis |
| Speaker: James Nance of Emory University |
| Contact: James Nagy, nagy@mathcs.emory.edu |
| Date: 2011-04-06 at 4:00PM |
| Venue: W306 |
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| Abstract: Amblyomma americanum, the Lone Star tick, is the predominant tick species throughout the southeast United States. Its significance as a threat to human health was not realized until recently. Recognized as an important disease vector, Amblyomma carry a serious bacteria, Ehrlichia chaffeensis, that causes human monocytic ehrlichiosis. In 1995, eleven cases of ehrlichiosis due to E. chaffeensis were identied in Faireld Glade, a retirement golf community near Crossivlle, Tennessee. The placement of "4-poster" acaricide feeders has been demonstrated to be a highly effective control method for eliminating Amblyomma populations. Here we formulate an economic criterion to evaluate various feeder placement scenarios within Faireld Glade that that minimize infected ticks and that tend toward future projects in optimization of this system. |
| Title: Bartle-Dunford-Schwartz Integration of scalar functions with respect to measures taking values in arbitrary topological vector spaces |
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| Seminar: Analysis and Differential Geometry |
| Speaker: Professor Iwo Labuda of The University of Mississippi |
| Contact: Michal Karonski, michal@mathcs.emory.edu |
| Date: 2011-04-05 at 4:00PM |
| Venue: MSC W301 |
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| Abstract: Please see website for abstract. |
| Title: Subgraphs of large degree and large girth in graphs and digraphs |
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| Seminar: Combinatorics |
| Speaker: Daniel Martin of Universidade Federal do ABC |
| Contact: Dwight Duffus, dwight@mathcs.emory.edu |
| Date: 2011-04-01 at 4:00PM |
| Venue: W306 |
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| Abstract: In 1983 Carsten Thomassen conjectured that for all positive integers $k$ and $g$ there exists $d$ such that all graphs with average degree at least $d$ contain a subgraph of average degree at least $k$ and girth at least $g$. In this talk we discuss what is known about this problem and its relationship with other problems. We also give a proof that the analogous problem for directed graphs has an affirmative answer. |
| Title: Isoperiodic Deformations and Stability for Finite-Gap Vortex Filaments |
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| Seminar: Analysis and Differential Geometry |
| Speaker: Professor Thomas A. Ivey of College of Charleston |
| Contact: Vladmir Oliker, oliker@mathcs.emory.edu |
| Date: 2011-03-30 at 4:00PM |
| Venue: MSC W201 |
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| Abstract: The subject of this lecture concerns an integrable evolution equation for curves in R3, and the stability of some of its knotted solutions. |
| Title: EUMMA - Google PageRank |
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| Seminar: Mathematics |
| Speaker: Dr. Paul Horn of Emory University |
| Contact: Jodi-Ann Wray, jcwray@emory.edu |
| Date: 2011-03-30 at 6:00PM |
| Venue: MSC W301 |
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| Abstract: |
| Title: Zero cycles of degree one on principal homogeneous spaces |
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| Defense: Algebra |
| Speaker: Jodi Black of Emory University |
| Contact: R. Parimala, parimala@mathcs.emory.edu |
| Date: 2011-03-29 at 3:00PM |
| Venue: W306 |
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| Abstract: |
| Title: Numerical Methods for Optimal Experimental Design of Ill-posed Problems |
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| Defense: Dissertation |
| Speaker: Zhuojun Magnant of Emory Unviersity |
| Contact: Zhuojun Magnant, ztang4@emory.edu |
| Date: 2011-03-28 at 9:00AM |
| Venue: MSC E408 |
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| Abstract: The two goals of this thesis are to develop numerical methods for solving large-scale optimal experimental design problems efficiently and to apply optimal experimental design ideas to applications in regularization techniques and geophysics.\\ \\ The thesis can be divided into three parts. In the first part, we consider the problem of experimental design for linear ill-posed inverse problems. The minimization of the objective function in the classic A-optimal design is generalized to a Bayes risk minimization with a sparsity constraint. We present efficient algorithms for applications of such designs to large-scale problems. This is done by employing Krylov subspace methods for the solution of a subproblem required to obtain the experiment weights. The performance of the designs and algorithms is illustrated with a one-dimensional magnetotelluric example and an application to two-dimensional super-resolution reconstruction with MRI data.\\ \\ In the second part, we find the optimal regularization for linear ill-posed problems. We propose an optimal $L_2$ regularization approach enabling us to obtain inexpensive and good solutions to the inverse problem. In order to reduce the computational cost, several sparsity patterns are added to the regularization operator. Numerical experiments will show that our optimal $L_2$ regularization approach provides much better results than the traditional Tikhonov regularization.\\ \\ In the last part of the thesis, we design optimal placement of sources and receivers in a $CO_2$ injection monitoring. An optimal criteria is proposed based on a target zone and different treatments for placing sources and receivers are discussed. |
| Title: Coordinate Percolation |
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| Colloquium: Combinatorics |
| Speaker: Peter Winkler of Dartmouth College |
| Contact: Dwight Duffus, dwight@mathcs.emory.edu |
| Date: 2011-03-28 at 4:00PM |
| Venue: MSC W201 |
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| Abstract: Percolation is the study of random subgraphs of a graph. In coordinate percolation, the big graph is a grid of some kind, and inclusion of a vertex depends on random values associated with the lines that cross there. Coordinate percolation arises in scheduling problems (in contrast to independent percolation, intended originally as a model for porous material).\\ \\ We'll consider several examples, including one that is notoriously difficult, and another that becomes miraculously easy when (with Lizz Moseman, NIST) combinatorial methods are applied. |
| Title: Limits of translates of divergent geodesics and Integral points on one-sheeted hyperboloids |
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| Seminar: Algebra and Number Theory |
| Speaker: Nimish Shah of Ohio State |
| Contact: Ken Ono, ono@mathcs.emory.edu |
| Date: 2011-03-22 at 3:00PM |
| Venue: MSC E406 |
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| Abstract: For any uniform lattice $\Gamma$ in $SL_2(R)$, we describe the limit distribution of the orthogonal translates of a {\it divergent} geodesic in $\Gamma/SL_2(R)$. We consider an important application to the theory of quadratic forms. This is joint work with Hee Oh. |