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Title: Taming the Big Data Elephant with Query Explanations
Colloquium: N/A
Speaker: Sudeepa Roy of University of Washington
Contact: Vaidy Sunderam, vss@emory.edu
Date: 2015-02-23 at 4:00PM
Venue: W303
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Abstract:
In recent years, the availability of big data has resulted in a growing number of users from a variety of backgrounds interested in identifying and interpreting the general trends and anomalies of large datasets. This presents an imminent requirement of sophisticated data analysis tools that can provide qualitative information based on query answers on such datasets. In this talk, I will describe my current research on developing a principled framework for explaining query answers in terms of intervention (explanations are changes in the database that change the observed query answers). I will present our solutions to core challenges in this task such as obtaining concise descriptions of explanations, handling inherent dependencies of database tuples, and achieving real-time efficiency in large explanation spaces. Then, I will briefly talk about my research in the areas of probabilistic databases, provenance, information extraction, and crowd sourcing. The unifying theme of this research is to address defining characteristics of modern datasets: uncertainty, unreliability, lack of structure, and the effects of human participation. I will conclude with my long-term vision of incorporating techniques to handle these challenges in the generic data explanation framework.
Title: Looking for Structure in Real-World Networks
Seminar: Computer Science
Speaker: Blair Sullivan of Department of Computer Science North Carolina State University
Contact: Michele Benzi, benzi@mathcs.emory.edu
Date: 2015-02-17 at 4:00PM
Venue: W306
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Abstract:
Graphs offer a natural representation of relationships within data -- for example, edges can be defined based on any user-defined measure of similarity (e.g. word frequencies, geographic proximity of observation, gene expression levels, or overlap in sample populations) or interaction (e.g. social friendship, communication, chemical bonds/protein bindings, or migration). As such, network analysis is playing an increasingly important role in understanding the data collected in a wide variety of social, scientific, and engineering settings. Unfortunately, efficient graph algorithms with guaranteed performance and solution quality are impossible in general networks (according to computational complexity).\\ \\ One tantalizing approach to increasing scalability without sacrificing accuracy is to employ a suite of powerful (parameterized) algorithms developed by the theoretical computer science community which exploit specific forms of sparse graph structure to drastically reduce running time. The applicability of these algorithms, however, is unclear, since the (extensive) research effort in network science to characterize the structure of real-world graphs has been primarily focused on either coarse, global properties (e.g., diameter) or very localized measurements (e.g., clustering coefficient) -- metrics which are insufficient for ensuring efficient algorithms.\\ \\ We discuss recent work on bridging the gap between network analysis and structural graph algorithms, answering questions like: Do real-world networks exhibit structural properties that enable efficient algorithms? Is it observable empirically? Can sparse structure be proven for popular random graph models? How does such a framework help? Are the efficient algorithms associated with this structure relevant for common tasks such as evaluating communities, clustering and motifs? Can we reduce the (often super-exponential) dependence of these approaches on their structural parameters? Joint work with E. Demaine, M. Farrell, T. Goodrich, N. Lemons, F. Reidl, P. Rossmanith, F. Sanchez Villaamil and S. Sikdar.
Title: Lattice point counting and the Hodge theory of degenerating hypersurfaces
Seminar: Algebra
Speaker: Eric Katz of Waterloo
Contact: David Zureick-Brown, dzb@mathcs.emory.edu
Date: 2015-02-17 at 4:00PM
Venue: W304
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Abstract:
Geometric properties of generic hypersurfaces in projective toric varieties are often determined by the combinatorics of their corresponding Newton polytopes, in particular, by the lattice point enumeration of dilates of the Newton polytope. Pioneering work of Danilov-Khovanskii gave combinatorial descriptions for certain topological and Hodge theoretic invariants in terms of combinatorics. In joint work with Alan Stapledon, we outline an alternative approach. Here, we degenerate the hypersurface into a union of linear subspaces and use the limit mixed Hodge structure to understand the cohomology. In addition, we discuss a theory of the combinatorics of subdivisions of polytopes to understand invariants of degenerating families of hypersurfaces.
Title: Data-Intensive Scientific Discovery in the Big Data Era
Colloquium: N/A
Speaker: James Faghmous of University of Minnesota
Contact: Vaidy Sunderam, vss@emory.edu
Date: 2015-02-13 at 3:00PM
Venue: W303
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Abstract:
Data science has become a powerful tool to extract knowledge from the large data. However, despite massive data growth in the sciences, it remains unclear whether Big Data can lead to scientific breakthroughs. I will introduce a new knowledge discovery paradigm -- theory-guided data science -- that brings together novel data analysis methods and powerful scientific theory to extract knowledge from complex spatio-temporal data. The principles of this paradigm will be demonstrated with a data mining application to monitor the global ocean system.\\ \\ Bio:\\ James Faghmous is a Research Associate at the University of Minnesota where he develops new data science methods for data-intensive scientific discovery. In 2015, James received an inaugural NSF CRII Award for junior faculty and his doctoral dissertation received the "Outstanding Dissertation Award" in Science and Engineering at the University of Minnesota. James received his Ph.D. from the University of Minnesota in 2013 where he was part of a 5-year \$10M NSF Expeditions in Computing project to understand climate change from data. He graduated Magna Cum Laude in 2006 with a B.Sc. in computer science from the City of College of New York where he was a Rhodes and a Gates Scholar nominee.
Title: Text Analytics-from small to BIG-Challenges and Ideas
Seminar: Computer Science
Speaker: John Kuriakose of Infosys Labs
Contact: Jinho Choi, choi@mathcs.emory.edu
Date: 2015-02-06 at 3:00PM
Venue: W303
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Abstract:
This talk will explore issues and challenges faced in Text Analytics through the lens of real-world use-cases. I will show a demo of our existing News analytics system that leverages Entity and Event extraction and then describe 5 major challenges that we want to address.
Title: Pencils of quadrics and the arithmetic of hyperelliptic curves
Colloquium: Number Theory
Speaker: Jerry Wang of Princeton University
Contact: David Borthwick, davidb@mathcs.emory.edu
Date: 2015-02-05 at 4:00PM
Venue: W303
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Abstract:
Finding integral and rational solutions to polynomial equations with integer coefficients has always been a fascinating subject to mathematicians. In this talk we will look at the hyperelliptic equations y^2 = f(x) and discuss how many solutions they have typically. There has been several results on this recently by Manjul Bhargava and his collaborators via the study of rational orbits of certain representations of reductive groups and by applying the techniques of geometry of numbers to count these orbits. We will discuss our recent joint work with Manjul Bhargava and Benedict Gross on solutions to the hyperelliptic equations over odd degree field extensions of Q and see how the geometry of pencils of quadrics plays a pivotal role in this work.
Title: Umbral Moonshine
Colloquium: Number Theory
Speaker: John Duncan of Case Western Reserve University
Contact: David Borthwick, davidb@mathcs.emory.edu
Date: 2015-02-03 at 4:00PM
Venue: W303
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Abstract:
Umbral moonshine is a new and rapidly developing field at the intersection of number theory, group theory and mathematical physics. I will introduce the subject, describe its main challenges, and present some recent progress, including joint work with Michael Griffin and Ken Ono.
Title: Helioseismology from South Pole
Seminar: Numerical Analysis and Scientific Computing
Speaker: Stuart Jefferies of University of Hawaii
Contact: James Nagy, nagy@mathcs.emory.edu
Date: 2015-01-30 at 12:00AM
Venue: W306
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Abstract:
This talk will describe work on helioseismic observations from South Pole. The observations play a significant role in improving our understanding of the Sun's interior, not only with fundamental measurements such as the determination of the internal sound speed and rotational profiles, but also with the development of important techniques such as time-distance analysis. I will finish with a travel log of a typical expedition to South Pole.
Title: Descent and base change with view towards the Artin conjecture
Colloquium: Number Theory
Speaker: Jayce Getz of Duke University
Contact: David Borthwick, davidb@mathcs.emory.edu
Date: 2015-01-27 at 4:00PM
Venue: W303
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Abstract:
The Langlands functoriality conjecture is a powerful unifying force in mathematics, illuminating connections between (at least) number theory, representation theory, mathematical physics, and algebraic geometry. It has only been established in limited, though important cases. In this talk we focus on a particular consequence of Langlands functoriality, namely the Artin conjecture, and use it as a touchstone to explain what is known and a new approach to move beyond it.
Title: Relative trace formulae with applications to arithmetic, geometry, and spectral theory
Colloquium: Number Theory
Speaker: Heekyoung Hahn of Duke University
Contact: David Borthwick, davidb@mathcs.emory.edu
Date: 2015-01-26 at 4:00PM
Venue: W303
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Abstract:
Relative trace formulae are arguably the most versatile and general tools available in the modern theory of automorphic forms. Starting with the oldest unsolved problem in mathematics and moving to Millennium prize problems we will explain concrete applications and motivation for relative trace formulae in low-dimensional cases. We will then explain our work on extending the relative trace formula to its natural level of generality with a view towards specific problems in arithmetic, geometry, and spectral theory.