All Seminars
| Title: (Re-) Discovering Lost Web Pages |
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| Seminar: Computer Science |
| Speaker: Michael Nelson of Old Dominion University |
| Contact: Joan Smith, jsmit52@emory.edu |
| Date: 2009-10-02 at 3:00PM |
| Venue: MSC W301 |
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| Abstract: Missing web pages (pages that return the "404 Page Not Found" error) are part of the browsing experience. So too are pages whose owners failed to renew their domain and whose old URls now have unexpected content. Users that encounter a missing page or unexpected page may try to use search engines to discover either the same page at a new location or a similar, "good enough" page to satisfy their information needs, but this can be laborious. To address this need, we are developing a semi-automated framework to assist users to first discover the topic of the missing page, and then locate the same or similar page at a new URl.\\ \\ We have been investigating a number of techniques to discover the "aboutness" of an unknown web page. If the page is in the internet Archive's Wayback Machine or in a search engine cache, the user may be satisfied with the old copy. If an old copy is insufficient, we can use either the page's title or generate a lexical signature to serve as a queiry to a search engine to find the resource. A lexcial signature is a 5-7 word "abstract" of a document that is suitable for using as a queiry to a search engine. The performance of titles and lexcial signatures are comparable, with both achieving over 60 percent success. The combination of titles and lexical signatures from link neighborhoods as well as using tags from del.icio.us, but at this point neither method performs well.\\ \\ Speaker Bio:\\ Michael L. Nelson is an associate professor of computer science at Old Dominion University. Prior to joining ODU, he worked at NASA Langley Research Center from 1991-2002. He is co-editor of the OAI-PMH and OAI-ORE specifications and is a 2007 recipient of an NSF CAREER award. In 2008, Dr. Nelson was named a "Digital Preservation Pioneer" by the Library of Congress. He has developed many digital libraries, including the NASA technical Report Server. His research interests include repository-object interaction and alternative approaches to digital preservation. More information about Dr. Nelson can be found at http://www.cs.odu.edu/~min/ |
| Title: Vertex-coloring edge-weightings |
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| Seminar: Combinatorics |
| Speaker: Michal Karonski of Mathematics and Computer Science, Emory University and Faculty of Mathematics and Computer Science, Adam Mickiewicz University |
| Contact: Dwight Duffus, dwight@mathcs.emory.edu |
| Date: 2009-10-02 at 4:00PM |
| Venue: W306 |
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| Abstract: A weighting of the edges of a graph with integer weights gives rise to a weighting of the vertices, the weight of a vertex being the sum of the weights of its incident edges. It is natural to consider edge weighting where we require that adjacent vertices have different weights, that is, that the vertex weighting induce a proper coloring of the graph.\\ \\ Conjecture [Karonski, Luczak and Thomason, 2001]. Edges of every graph that does not contain a component isomorphic to an edge can be weighted with the integers {1,2,3} such that the resultant vertex weighting is a proper coloring.\\ \\ In my talk I will discuss some recent developments regarding the above conjecture. |
| Title: CAT(0) Cubical Complexes in Group Theory |
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| Seminar: Topology |
| Speaker: Professor Michah Sageev of Technion University |
| Contact: Emily Hamilton, emh@mathcs.emory.edu |
| Date: 2009-09-29 at 3:00PM |
| Venue: MSC E408 |
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| Abstract: |
| Title: The Near-Field Single Reflector Problem, a Generalized Legendre Transform and Breaking of the Monge-Kantorovich Optimality Property |
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| Seminar: Analysis and Differential Geometry |
| Speaker: Tobias Graf of Emory University |
| Contact: Vladimir Oliker, oliker@mathcs.emory.edu |
| Date: 2009-09-29 at 4:00PM |
| Venue: MSC W301 |
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| Abstract: In recent years, the framework of Monge-Kantorovich optimal transport has proven quite successful in the design of innovative optical systems. A major improvement from a theoretical point of view as well as for practical applications is the design of free-form lenses and mirrors. The optimal transport approach has been applied to a variety of design problems for systems consisting of one or two lenses or reflectors. A classical problem in optical design is the so-called illumination or near-field single reflector problem. In this problem, one needs to design a reflecting surface such that the rays emitted from a non-isotropic source are reflected in such a way to create a prescribed in advance illumination pattern on a given target set at a finite distance. In this talk, we will discuss how the near-field problem fits into a generalized optimal transport framework and how solutions to this transport problem are related to solutions of the near-field problem. |
| Title: Motives of quadrics II |
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| Seminar: Algebra |
| Speaker: V. Suresh of Emory University and University of Hyderabad |
| Contact: R. Parimala, parimala@mathcs.emory.edu |
| Date: 2009-09-29 at 4:00PM |
| Venue: MSC W303 |
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| Abstract: |
| Title: Polynomials non-negative on non-compact semialgebraic sets |
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| Seminar: Algebra |
| Speaker: Ha Nguyen of Emory University |
| Contact: Vicki Powers, vicki@mathcs.emory.edu |
| Date: 2009-09-28 at 4:00PM |
| Venue: MSC W303 |
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| Abstract: Recently, M. Marshall answered a long-standing question in real algebraic geometry by showing that if $f(x,y) \in \mathbf{R}[x,y]$ and $f(x,y) \geq 0$ on the strip $[0,1] \times \mathbf{R}$, then $f$ has a representation $f = \sigma_0 + \sigma_1 x(1 - x)$, where $\sigma_0, \sigma_1 \in \mathbf{R}[x,y]$ are sums of squares. In this talk, we give the background to this result, which goes back to Hilbert's 17th problem, and our generalizations to other non-compact basic closed semialgebraic sets of $\mathbf{R}^2$ which are contained in strip. We also give some negative results. |
| Title: Record Linkage: Concepts and Practice with FRIL |
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| Seminar: Computer Science |
| Speaker: Pawel Jurczyk of Emory University |
| Contact: James Lu, jlu@mathcs.emory.edu |
| Date: 2009-09-25 at 3:00PM |
| Venue: MSC W301 |
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| Abstract: Record Linkage is the task of finding entries that refer to the same entity in two or more data sets. It is useful for joining and cleaning data sets that do not have unique common keys, and is important in many studies in business, public health, sociology and psychology, where reconciling independently collected data sets is often the most important and time-consuming first step. In this talk, we describe the basic concepts of automated record linkage and demonstrate FRIL, an open-source software collaboratively developed at Emory and the CDC that facilitates fast and accurate linkages. FRIL implements an array of standard record matching algorithms as well as a large number of user tunable parameters for improving efficiency and precision. It provides a friendly, easy to use interface and a set of useful visualization tools for quick user feedbacks. Since its release in 2008, FRIL has been widely adopted, including uses by research groups at the National Center on Addiction and Substance Abuse, the Harvard Business School and the NIH. This talk should be of interest to faculty and graduate students whose research involve data collection, integration, and cleansing. Pawel Jurczyk is a Ph.D. Candidate in the Computer Science and Informatics Program at Emory University. His interest includes distributed computing, distributed database query processing, and data/information privacy. He has been an ORISE fellow at the CDC since 2007, and has taught courses in Introduction to Computer Science and Databases. |
| Title: Partitions of the Subset Lattice into Intervals |
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| Seminar: Combinatorics |
| Speaker: William T. Trotter of School of Mathematics, Georgia Tech |
| Contact: Dwight Duffus, dwight@mathcs.emory.edu |
| Date: 2009-09-25 at 4:00PM |
| Venue: W306 |
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| Abstract: |
| Title: Motives of quadrics, I |
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| Seminar: Algebra |
| Speaker: V. Suresh of University of Hyderabad and Emory University |
| Contact: Parimala, parimala@mathcs.emory.edu |
| Date: 2009-09-22 at 4:00PM |
| Venue: MSC W303 |
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| Abstract: |
| Title: Counting Resonances in Hyperbolic Space |
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| Seminar: Analysis and Differential Geometry |
| Speaker: David Borthwick of Emory University |
| Contact: David Borthwick, davidb@mathcs.emory.edu |
| Date: 2009-09-22 at 4:00PM |
| Venue: MSC W301 |
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| Abstract: I'll introduce some basic techniques for estimating determinants of operators. Then I'll show how these techniques are applicable to the problem of counting resonances for perturbations of the hyperbolic plane. |