All Seminars
| Title: Unitary descent properties |
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| Seminar: Algebra |
| Speaker: Eva Bayer of Swiss Federal Institute of Technology, Lausanne (EPFL) |
| Contact: R. Parimala, parimala@mathcs.emory.edu |
| Date: 2009-12-07 at 4:00PM |
| Venue: W306 |
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| Abstract: Let $k$ be a field of characteristic $\not = 2$, let $L/k$ be an odd degree extension and let $U$ be a unitary group defined over $k$. It is well--known that the natural map $H^1(k,U) \to H^1(L,U)$ is injective. Suppose that $L/k$ is Galois with group $G$. Is then $H^1(k,U) \to H^1(L,U)^G$ a bijection? This is true for orthogonal groups, and one of the main ingredients in the proof is a result of Rosenberg and Ware concerning a descent property for Witt rings of quadratic forms, namely that $W(L)^G \simeq W(k)$. This talk will present a generalization of the Rosenberg--Ware theorem to Witt groups of hermitian forms, as well as some applications of this result, in particular to the above mentioned Galois cohomology descent question. |
| Title: Learning With Changing Language Data |
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| Colloquium: Computer Science |
| Speaker: Mark Dredze of Johns Hopkins University and Human Language Technology Center of Excellence |
| Contact: Eugene Agichtein, eugene@mathcs.emory.edu |
| Date: 2009-12-04 at 2:00PM |
| Venue: MSC W301 |
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| Abstract: The information revolution has produced huge quantities of knowledge in the form of natural human language. This explosion of data has pushed natural language processing (NLP) research towards empirical data driven methods, which rely on statistical machine learning. This effort has produced numerous high quality tools for processing language, including knowledge extraction, information organization and automated translation of numerous languages. With more data and better statistical methods, the state of the art advances. Behind the success of this statistical movement is a reliance on statistical methods that are susceptible to changes in data, a particular problem for language data which naturally transitions between topical domains, genres, formats, dialects and languages. High performing systems fail with even subtle changes to language input, like a change in the topic domain. This talk will survey recent NLP successes in tackling complex natural language problems as well as challenges posed by changes in language data. I will present several approaches to solving domain change challenges that adapt a learned statistical model between one source domain and a new different target domain. I describe Confidence Weighted Learning, a streaming machine learning algorithm designed for the types of data distributions common in language tasks. I show how Confidence Weighted Learning both improves learning in NLP tasks and can be applied to confront the challenges associated with data shifts. BIO: Mark Dredze is as an Assistant Research Professor in the department of Computer Science and a Senior Research Scientist at the Human Language Technology Center of Excellence at The Johns Hopkins University. His research interests include machine learning, natural language processing and intelligent user interfaces. His focus is on novel applications of machine learning to solve language processing challenges as well as applications of machine learning and natural language processing to support intelligent user interfaces for information management. He earned his PhD from the University of Pennsylvania and has worked at Google, IBM and Microsoft. |
| Title: On $K_t$-saturated Graphs |
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| Seminar: Combinatorics |
| Speaker: Kinnari Amin of Emory University |
| Contact: Dwight Duffus, dwight@mathcs.emory.edu |
| Date: 2009-12-04 at 4:00PM |
| Venue: W306 |
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| Abstract: Let $H$ be a graph. An $H$-free graph $G$ is called $H$-saturated if the addition of any new edge to $G$ results in a subgraph isomorphic to $H$. The minimum size of an $H$-saturated graph on n vertices is denoted by sat($n$, $H$). The edge spectrum for the family of graphs with property $P$ is the set of all sizes of graphs with property $P$. In this talk, I will present new results about the edge spectrum of $ K_t$-saturated graphs. This is joint work with Jill Faudree and Ronald Gould. |
| Title: Meet Lie groups (and some of their applications and misapplications in physics) |
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| Graduate Student Seminar: N/A |
| Speaker: Skip Garibaldi of Emory University |
| Contact: Pascal Philipp, pphilip@emory.edu |
| Date: 2009-12-02 at 4:00PM |
| Venue: MSC W201 |
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| Abstract: You've met Lie groups already in your sophomore linear algebra class, in the sense that the n-by-n invertible matrices make up a Lie group. This talk will give some more examples of Lie groups, describe one of their classic applications to physics, and mention how they are being applied today. As part of the graduate student seminar series, this talk will be understandable to all mathematics graduate students. The talk should also be understandable by physics graduate students. |
| Title: From Droplets to Cloud: Towards Privacy-Preserving Integration of Distributed Heterogeneous Data |
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| Defense: Dissertation |
| Speaker: Pawel Jurczyk of Emory University |
| Contact: Pawel Jurczyk, pjurczy@emory.edu |
| Date: 2009-12-01 at 3:00PM |
| Venue: MSC W201 |
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| Abstract: With the trend of cloud computing, data and computing are moved away from desktop and are instead provided as a service from the cloud. Data-as-a-service enables access to a wealth of data across distributed and heterogeneous data sources in the cloud. It remains a challenge, however, to ensure the privacy, interoperability, and scalability for such services.\\ \\ We designed and developed DObjects, a general-purpose P2P-based query and data operations infrastructure that can be deployed in the cloud and provides access to heterogeneous data sources. The system builds on top of a distributed mediator-wrapper architecture where individual system nodes serve as mediators and/or wrappers and interact with each other in a P2P fashion what guarantees good scalability. As an analogy, the system nodes can be considered as droplets, small elements that provide similar functionality in the cloud. Just as thousands or millions of droplets form a single drop in nature, in cloud computing, groups of droplets that provide similar functionality can form a micro-cloud. Micro-clouds are an integral part of the whole cloud computing system and can provide specific services to users.\\ \\ The dissertation also discusses the novel dynamic query execution engine within the data query infrastructure that dynamically adapts to network and node (or droplet) conditions. The query processing is capable of fully benefiting from all the distributed resources to minimize the query response time and maximize system throughput. In addition to leveraging the traditional distributed query optimization techniques, the (sub)queries are deployed and executed on droplets in a dynamic and iterative manner in order to guarantee the best reaction to network and resource dynamics.\\ \\ Finally, the dissertation presents an extension to the basic DObjects model that enables access to private data that is distributed and needs anonymization. The extension enables droplets to form virtual groups in order to addresses two important privacy issues for the sensitive data: privacy of data subjects and confidentiality of data providers. The dissertation discusses decentralized protocols that enable data sharing for horizontally partitioned databases given these constraints. These protocols can be run by the groups of droplets. Concretely, given a query spanning multiple databases, the query results do not contain individually identifiable information. In addition, institutions do not reveal their databases to each other apart from the query results. |
| Title: Brauer-Manin obstructions on K3 surfaces |
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| Seminar: Algebra |
| Speaker: Patrick Corn of Emory University |
| Contact: Skip Garibaldi, skip@mathcs.emory.edu |
| Date: 2009-12-01 at 4:00PM |
| Venue: MSC W303 |
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| Abstract: There has been a great deal of recent research on the arithmetic of K3 surfaces, some of which has centered around the Brauer-Manin obstruction to the Hasse principle. In this talk, I'll give some background and discuss some of the results and open questions in this area. |
| Title: Chow motives II |
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| Seminar: Algebra |
| Speaker: V. Suresh of University of Hyderabad and Emory University |
| Contact: R. Parimala, parimala@mathcs.emory.edu |
| Date: 2009-11-23 at 4:00PM |
| Venue: MSC E408 |
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| Abstract: |
| Title: Automatic Modeling of Procedural Knowledge and Feedback Generation in Tutoring System for Computer Science |
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| Seminar: Computer Science |
| Speaker: Davide Fossati of Georgia Tech, College of Computing |
| Contact: James J. Lu, jlu@mathcs.emory.edu |
| Date: 2009-11-20 at 3:00PM |
| Venue: MSC W301 |
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| Abstract: This research takes place in the larger context of the study of one-on-one tutoring, a form of instruction that has been shown to be very effective. We conducted a study of human tutoring in the domain of Computer Science data structures, to understand which features and strategies of human tutoring are important for learning. We developed an Intelligent Tutoring System, iList, that helps students learn linked lists. One of the main advancements in iList is the presence of a Procedural Knowledge Model automatically extracted from student data. This model allows iList to provide effective reactive and proactive procedural feedback while a student is solving a problem. We tested five different versions of iList, differing in the level of feedback they can provide, in multiple classrooms, with a total of more than 200 students. The evaluation study showed that iList is effective in helping students learn; students liked working with the system; and the feedback generated by the most sophisticated versions of the system is helpful in keeping the students on the right path. \\ Davide Fossati (http://www.fossati.us) received his Ph.D. in Computer Science at the University of Illinois at Chicago in summer 2009. He also holds an M.Sc. degree in Computer Engineering from the Politecnico di Milano, Italy (2004), and an M.Sc. in Computer Science from the University of Illinois at Chicago (2003). His research focuses on applications of Artificial Intelligence in education, such as Intelligent Tutoring Systems, and computational models and tools to support formative assessment in Computer Science education. |
| Title: Geometric Methods in Group Theory and Graph Theory |
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| Seminar: Combinatorics |
| Speaker: Praphat Fernandes of Emory University |
| Contact: Dwight Duffus, dwight@mathcs.emory.edu |
| Date: 2009-11-20 at 4:00PM |
| Venue: W306 |
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| Abstract: I will introduce some basic notions from "large scale geometry" and carry out a brief survey of some of the applications to group theory and graph theory. I will mostly be concerned with infinite groups and graphs. |
| Title: Riemann's zeros and the rhythm of the primes |
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| 150th anniversary of the Riemann Hypothesis: Celebration of the |
| Speaker: David Borthwick of Emory University |
| Contact: Skip Garibaldi, skip@mathcs.emory.edu |
| Date: 2009-11-18 at 4:00PM |
| Venue: MSC W201 |
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| Abstract: Exactly 150 years ago, Riemann published a short paper (in German) called "On the Number of Primes Less Than a Given Magnitude." In it, he speculated that the zeros of the zeta function all lie on a certain line called the critical strip. This conjecture, now called the Riemann Hypothesis, is the greatest unsolved problem in all of mathematics. In this talk we'll introduce the Hypothesis and try to explain why mathematicians find this arcane-sounding problem so compelling. |