All Seminars
| Title: More Galois Theory |
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| Graduate Student Seminar: Algebra |
| Speaker: Dr. Eric Brussel of Emory University |
| Contact: TBA |
| Date: 2009-04-22 at 4:00PM |
| Venue: MSC W201 |
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| Abstract: The study of objects defined as fixed points under a Galois action is a big part of the algebra program at Emory. We develop the basic setup, using nothing but 1st year graduate algebra. |
| Title: Patching Brauer groups II |
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| Seminar: Algebra |
| Speaker: Feng Chen of IIT Bombay and Emory University |
| Contact: R. Parimala, parimala@mathcs.emory.edu |
| Date: 2009-04-21 at 3:00PM |
| Venue: MSC W303 |
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| Abstract: |
| Title: On a problem from Crux Mathematicorum |
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| Seminar: Combinatorics |
| Speaker: Bill Sands of Math and Statistics, University of Calgary |
| Contact: Dwight Duffus, dwight@mathcs.emory.edu |
| Date: 2009-04-17 at 4:00PM |
| Venue: MSC W301 |
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| Abstract: Suppose you are given four cards, each containing four nonnegative real numbers, written one below the other, so that the sum of the numbers on each card is 1. You are allowed to put the cards in any order you like, then you write down the first number from the first card, the second number from the second card, the third number from the third card, and the fourth number from the fourth card, and you add these four numbers together. What is the smallest interval [a, b] so that, no matter which cards you are given, there is always an ordering of the cards so that the sum will lie in [a, b]? I will give the history of this problem and what I know about it. |
| Title: Surveying The Landscape Of Threats Facing Users In The Social Web |
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| Seminar: Computer Science |
| Speaker: Steve Webb, Ph.D. of Purewire, Inc. |
| Contact: Li Xiong, lxiong@mathcs.emory.edu |
| Date: 2009-04-16 at 10:00AM |
| Venue: W302 |
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| Abstract: The World Wide Web is rapidly evolving into a "social Web" that is dominated by user-generated content and user-centric social interactions. Although this evolution enhances the usability of the Web, it also presents a number of information security and privacy challenges. Some of these challenges are familiar such as malware and spam, while others are new and unique to the social Web such as fraudulent user profiles. In this talk, we survey the landscape of threats facing users in the social Web, and we explore interesting research challenges that arise when countering these threats. The threats facing social Web users can be broadly categorized into three distinct classes: traditional attacks, socially enhanced attacks, and social Web-specific attacks. In the talk, we will discuss each of these attack classes and examine numerous examples that have been observed over the past few years. These examples are real-world incidents that have already affected specific social Web environments (e.g., MySpace, Facebook, etc.), highlighting the practical importance of these attacks and their impact on millions of social Web users. We will also investigate various countermeasures for these threats and discuss important research questions that remain unanswered.\\ \\ Bio:\\ \\ Dr. Steve Webb is a research scientist at Purewire, Inc. and the chief architect of PurewireTrust.org, a free online portal that maintains portable reputations for people, places, and things. Dr. Webb has 10 years of experience in researching security threats that target information systems such as P2P networks, email systems, the World Wide Web, and social networking environments. He holds a Ph.D. in Computer Science from the Georgia Institute of Technology, where he published more than a dozen academic articles on various information security and privacy issues, including spam, phishing, and information warfare. |
| Title: The Role Mining Problem - A Formal Perspective |
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| Seminar: Computer Science |
| Speaker: Vijay Atluri of Rutgers University |
| Contact: Li Xiong, lxiong@mathcs.emory.edu |
| Date: 2009-04-10 at 3:00PM |
| Venue: MSC W301 |
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| Abstract: Role based access control is well accepted as the standard best practice for access control within applications and organizations. Role engineering, the task of defining roles and associating permissions to them, is essential to realize the full benefits of the role-based access control paradigm. The essential question is how to devise a complete and correct set of roles -- this depends on how you define goodness/interestingness (when is a role good/interesting?) We define the role mining problem (RMP) as the problem of discovering an optimal set of roles from existing user permissions. In addition to the above basic RMP, we introduce two different variations of the RMP, called the delta-approx RMP and the Minimal Noise RMP that have pragmatic implications. Our main contribution is to formally define RMP, analyze its theoretical bounds, and present heuristic solutions to find the optimal set of roles based on subset enumeration. We place this in the framework of matrix decomposition which is applicable to many other domains including text mining. \\ \\ Bio:\\ \\ Dr. Vijay Atluri received her Ph.D. in Information Technology from George Mason University, USA. She is currently a Professor of Computer Information Systems in the MSIS Department, and research director for the Center for Information Management, Integration and Connectivity (CIMIC) at Rutgers University. Dr. Atluri's research interests include Information Systems Security, Privacy, Databases, Workflow Management, Spatial Databases, Multimedia and Distributed Systems. Currently, she serves as a member of the Steering Committee and the secretary/treasurer for ACM Special Interest Group on Security Audit and Control (SIGSAC), and chair of the IFIP WG11.3 on Data and Application Security. |
| Title: Ramification in bad characteristics |
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| Seminar: Algebra |
| Speaker: David Saltman of Center for Communications Research, Princeton |
| Contact: R. Parimala, parimala@mathcs.emory.edu |
| Date: 2009-04-07 at 4:00PM |
| Venue: MSC W303 |
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| Abstract: Let $C$ be a curve over a $p-$adic field $F$ and $K = F(C)$. For division algebras of exponent prime to $p$, it is known that index divides the square of the exponent and division algebras of prime degree are cyclic. Both results avoid the prime $p$ because in that case there is no good theory of ramification of Brauer group elements. However, one can try and avoid this obstacle by defining the ramification group of a discrete valued field $K$ with valuation ring $R$ as the quotient of Brauer groups $Br(K)/Br(R)$ and then study the functorial properties of this quotient. One is then led to the complete case and to consider the paper ``A generalization of local class field theory by using K groups I'' by Kazuya Kato (J Fac Sci Sec. IA 26, 2 303-376). We will discuss the progress we have made on this problem using Kato's work. |
| Title: Contact geometry, open books and monodromy |
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| Colloquium: Topology |
| Speaker: John Etnyre of Georgia Tech |
| Contact: Aaron Abrams, abrams@mathcs.emory.edu |
| Date: 2009-04-06 at 3:00PM |
| Venue: W306 |
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| Abstract: Recall that an open book decomposition of a 3-manifold M is a link L in M whose complement fibers over the circle with fiber a Seifert surface for L. Giroux's correspondence relates open book decompositions of a manifold M to contact structures on M. This correspondence has been fundamental to our understanding of contact geometry. An intriguing question raised by this correspondence is how geometric properties of a contact structure are reflected in the monodromy map describing the open book decomposition. In this talk I will show that there are several interesting monoids in the mapping class group that are related to various properties of a contact structure (like being Stein fillable, weakly fillable, . . .). I will also show that there are open book decompositions of Stein fillable contact structures whose monodromy cannot be factored as a product of positive Dehn twists. This is joint work with Jeremy Van Horn-Morris and Ken Baker. |
| Title: Density of isoperimetric spectra |
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| Colloquium: Topology |
| Speaker: Noel Brady of University of Oklahoma |
| Contact: Aaron Abrams, abrams@mathcs.emory.edu |
| Date: 2009-04-06 at 4:00PM |
| Venue: W306 |
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| Abstract: |
| Title: Digital Identity Management and Protection |
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| Seminar: Computer Science |
| Speaker: Elisa Bertino of CS Department, CERIAS, Purdue University |
| Contact: Li Xiong, lxiong@mathcs.emory.edu |
| Date: 2009-04-03 at 3:00PM |
| Venue: MSC W301 |
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| Abstract: \small Digital identity management (DIM) has emerged as a critical foundation for supporting successful interaction in today's globally interconnected society. It is crucial not only for the conduct of business and government but also for a large and growing body of electronic or online social interactions. Digital identity management is usually coupled with the notion of federation. The goal of federations is to provide users with protected environments to federate identities by the proper management of identity attributes. Federations provide a controlled method by which federation members can provide more integrated and complete services to a qualified group of individuals within certain sets of business transactions. By controlling the scope of access to participating sites, and by enabling secure, cross-domain transmission of user's personal information, federations can make the perpetration of identity frauds more difficult, as well as reduce their frequency, and their potential impact. In this talk we will first discuss basic digital identity concepts and requirements towards DIM solutions and we will overview relevant initiatives currently undergoing in academia and industry. We will then focus on the problem of identity theft and discuss an initial solution to the problem of establishing and protecting digital identity.\\ \\* \textbf{Biography:} Elisa Bertino is professor of Computer Science at Purdue University and serves as Research Director of the Center for Education and Research in Information Assurance and Security (CERIAS). Previously she was a faculty member at Department of Computer Science and Communication of the University of Milan where she directed the DB and SEC laboratory. She has been a visiting researcher at the IBM Research Laboratory (now Almaden) in San Jose, at the Microelectronics and Computer Technology Corporation, at Rutgers University, at Telcordia Technologies. Elisa Bertino is a Fellow member of IEEE and a Fellow member of ACM. She received the 2002 IEEE Computer Society Technical Achievement Award for "For outstanding contributions to database systems and database security and advanced data management systems" and the 2005 IEEE Computer Society Tsutomu Kanai Award "For pioneering and innovative research contributions to secure distributed systems". \\ |
| Title: On Graphs with a Given Endomorphism Monoid |
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| Defense: Dissertation |
| Speaker: Benjamin Shemmer of Emory University |
| Contact: Benji Shemmer, bshemmer@emory.edu |
| Date: 2009-04-02 at 4:00PM |
| Venue: MSC W201 |
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| Abstract: Hedlin and Pultr proved that for any monoid M there exists a graph G with endomorphism monoid isomorphic to M. We will give a construction G(M) for a graph with prescribed endomorphism monoid M. Using this construction we derive bounds on the minimum number of vertices and edges required to produce a graph with a given endomorphism monoid for various classes of finite monoids. |