All Seminars

Show:
Title: Transversality defect of two lagrangians and ternary index. Application: Formulas of (non) additivity of signatures and of linking forms
Seminar: Algebra
Speaker: Jean Barge of Ecole polytechnique
Contact: David Zureick-Brown, dzb@mathcs.emory.edu
Date: 2014-04-29 at 4:00PM
Venue: W302
Download Flyer
Abstract:
(This is a common work with Jean Lannes) To a pair of lagrangians in a symplectic space, we associate a symetric bilinear form well defined up to the addition of non-degenerate forms and which is itself non-degenerate if and only if the two lagrangians are transversal. To a triple of lagrangians, we associate a ternary index which is a raffinement of the Leray-Kashiwara index and which generalizes for any (commutative) ring the index defined by Wall for fields. We will explain how these two invariants can be used to compute signatures and linking forms of manifolds obtained by gluing.
Title: Online Social Dynamics and Wellbeing
Seminar: Computer Science
Speaker: Munmun De Choudhury of Georgia Institute of Technology
Contact: Eugene Agichtein, eugene@mathcs.emory.edu
Date: 2014-04-25 at 3:00PM
Venue: W301
Download Flyer
Abstract:
Social networks, Facebook and Twitter are continually creating rich repositories of information relating to our activities, emotion and linguistic expression. By leveraging such trails of data and developing machine learning models, we can not only elucidate core aspects of human behavior, but can begin to solve a vista of problems relating to our health behaviors, which have traditionally been challenging. In this talk I will discuss the harnessing of social media in reasoning about behavioral health concerns experienced by populations around major disruptions in life. In a first study, I will present analyses and computational models that make automated inferences about the status and dynamics of postpartum depression in new mothers via postings made on Twitter and Facebook. In a second study, we will examine the affective responses in Twitter experienced by communities in Mexico embroiled in protracted armed conflict and how they might indicate desensitization to violence. Broadly, I will discuss how this new line of research bears potential in informing the design of early-warning systems and interventions to help individuals and policymakers be more proactive about health and wellbeing.\\ \\ Bio:\\ \\ Munmun De Choudhury is currently an assistant professor at the School of Interactive Computing, Georgia Tech. Munmun’s research interests are in computational social science, with a specific focus on reasoning about our health behaviors from social digital footprints. She has been a recipient of the Grace Hopper Scholarship, recognized with an IBM Emergent Leaders in Multimedia award, and recipient of ACM SIGCHI 2014 best paper award and ACM SIGCHI honorable mention awards in 2012 and 2013. Earlier, Munmun was a postdoctoral researcher at Microsoft Research, a research fellow at Rutgers, and obtained a PhD in Computer Science from Arizona State University in 2011.
Title: Truth Is Stranger Than Fiction: A Look At Some Improbabilities
Seminar: N/A
Speaker: Dr. Rick Durrett of Duke University
Contact: TBA
Date: 2014-04-24 at 4:00PM
Venue: MSC E208
Download Flyer
Abstract:
Probability is full of surprises and paradoxes, most of which result from doing the calculation incorrectly. We will illustrate this using some familiar old stories and new ones: the Monty Hall problem, cognitive dissonance in Monkeys, the birthday problem, lottery coincidences, the sad story of Sally Clark, the 2012 election, and Warren Buffet’s bracket challenge.
Title: Rational connectivity and analytic contractibility
Seminar: Algebra
Speaker: Tyler Foster of University of Michigan
Contact: David Zureick-Brown, dzb@mathcs.emory.edu
Date: 2014-04-22 at 5:00PM
Venue: W302
Download Flyer
Abstract:
Let K be an algebraically closed field of characteristic 0. A smooth projective K-variety X is rationally connected if each pair of points in X is connected by a rational curve inside X. Over a non-archimedean field K, each of these rational curves becomes a contractible Berkovich space, so X has lots of contractible subvarieties. In fact more is true: In this talk, I will discuss recent work with Morgan Brown in which we prove that over the non-archimedean field K=C((t)), the Berkovich space associated to any smooth projective, rationally connected variety X is contractible.
Title: What is Ramsey-equivalent to a clique?
Seminar: Combinatorics
Speaker: Andrey Grinshpun of Massachusetts Institute of Technology
Contact: Dwight Duffus, dwight@mathcs.emory.edu
Date: 2014-04-21 at 4:00PM
Venue: W306
Download Flyer
Abstract:
TBA
Title: Image Recognition of Coronary Stents for Automatic Construction of Patient Specific Models
Honors Thesis: Applied Mathematics
Speaker: Shannon Buckley of Emory University
Contact: TBA
Date: 2014-04-16 at 1:00PM
Venue: E408
Download Flyer
Abstract:
Professor Veneziani and his team of graduate students have been working on the problem of modeling the effects that cardiovascular disease and the medical procedures employed to cure it have on the fluid dynamic process of the cardiovascular system. One of the newer solutions to this pressing disease is to insert a medical structure, called a stent, into the artery where a blockage is occurring. The modeling of this procedure requires the creation of a 3D model of the stent, which is then used in the algorithms. For real patients this data has previously been collected by manually recording the locations of the stent structures found in arthroscopic images of the patient’s arteries. To speed up this data collection process and provide more accurate data, we have created a MATLAB algorithm that uses image recognition software to automatically identify stent structures in the arthroscopic images and record their positions in the artery.
Title: Support Vector Machine Classification of Resting State fMRI Datasets Using Dynamic Network Clusters
Undergraduate Thesis Defense: Computer Science
Speaker: Hyo Yul Byun of Emory University
Contact: TBA
Date: 2014-04-15 at 10:30AM
Venue: E408
Download Flyer
Abstract:
TBA
Title: Quasirandom Discrete Structures and Powers of Hamilton Cycles
Seminar: Combinatorics
Speaker: Hiep Han of Emory University
Contact: Dwight Duffus, dwight@mathcs.emory.edu
Date: 2014-04-14 at 4:00PM
Venue: W306
Download Flyer
Abstract:
The aim of the talk is to give a gentle introduction into the topic of quasirandom discrete structures, putting emphasis on linear quasirandom hypergraphs and subsets of integers with small linear bias. We then continue with the study of the extremal behaviour of sparse pseudorandom graphs, a problem which has attracted the attention of many researchers in recent years. In particular, we shall discuss how to find powers of Hamilton cycles in sufficiently pseudorandom graphs.
Title: Live-Coding in Introductory Computer Science Education
Seminar: CS Undergraduate Honors Thesis Defense
Speaker: Amy Shannon of
Contact: Valerie Summet, valerie@mathcs.emory.edu
Date: 2014-04-04 at 10:00AM
Venue: W306
Download Flyer
Abstract:
Live-coding, an active learning technique in which students create code solutions during class through group discussion, is an under-used method in computer science education. However, this technique may produce greater learning gains than traditional lectures while requiring less time and effort from the instructor. We begin with a discussion of active learning techniques in STEM disciplines and then present a study to evaluate this instructional method in introductory Computer Science courses. While our results were inconclusive, we discuss several interesting and positive trends related to our live-coding results that deserve further investigation.
Title: Adaptive Approaches to Utility Computing for Scientific Applications
Defense: Dissertation
Speaker: Jaroslaw Slawinski of Emory University
Contact: Jaroslaw Slawinski, jaross@mathcs.emory.edu
Date: 2014-04-04 at 3:00PM
Venue: W306
Download Flyer
Abstract:
Coupling scientific applications to heterogeneous computational targets requires specialized expertise and enormous manual effort. To simplify the deployment process, we propose a novel adaptive approach that helps execute unmodified applications on raw computational resources. Our method is based on situation-specific “adapter” middleware that builds up target capabilities to fulfill application requirements, avoiding homogenization that may conceal platform-specific features. We investigate three dimensions of adaptation: performance, execution paradigm, and software deployment and propose the ADAPT framework as a methodology and a toolkit that automates execution-related tasks. For parallel applications, ADAPT matches logical communication patterns to physical interconnect topology and improves execution performance by reducing use of long-distance connections. In a proof-of-concept demonstration of application–platform paradigm transformation, ADAPT enables execution of unmodified MPI applications on the Map–Reduce Platform as a Service cloud by recreating and emulating missing MPI capabilities. To facilitate software deployment, ADAPT automatically provisions resources by applying soft-install adapters that dynamically transform target capabilities to satisfy application requirements. As a result of these types of transformations, a broader spectrum of resources can smoothly execute scientific applications, which brings the notion of utility computing closer to reality.