Seminars and Colloquia by Series

Wednesday, September 13, 2017 - 12:10 , Location: Skiles 006 , Howie Weiss , GA Tech , Organizer: Timothy Duff
Antibiotics have greatly reduced morbidity and mortality from infectious diseases. Although antibiotic resistance is not a new problem, it breadth now constitutes asignificant threat to human health. One strategy to help combat resistance is to find novel ways of using obsolete antibiotics.  For strains of E. coli and P. aeruginosa, pairs of antibiotics have been found where evolution of resistance to one increases, sometimes significantly, sensitivity to the other. These researchers have proposed cycling such pairs to treat infections. Similar strategies are being investigated to treat cancer. Using systems of ODEs, we model several possible treatment protocols using pairs and triples of such antibiotics, and investigate the speed of ascent of multiply resistant mutants. Rapid ascent would doom this strategy. This is joint work with Klas Udekwu (Stockholm University).
Wednesday, September 6, 2017 - 12:10 , Location: Skiles 006 , Virginia Ahalt , DoD , Organizer: Timothy Duff
SPORT is a 12-week *PAID* summer internship offered by the National Security Agency (NSA) that provides 8 U.S. Citizen graduate students the opportunity to apply their technical skills to current, real-world operations research problems at the NSA.  SPORT looks for strong students in operations research, applied math, computer science, data science, industrial and systems engineering, and other related fields. Program Highlights: -- Paid internship (12 weeks, late May to mid-August 2018) -- Applications accepted September 1 - October 31, 2017 -- Opportunity to apply operations research, mathematics, statistics, computer science, and/or engineering skills -- Real NSA mission problems -- Paid annual and sick leave, housing available, most travel costs covered -- Flexible work schedule -- Opportunity to network with other Intelligence Agencies
Wednesday, April 19, 2017 - 12:05 , Location: Skiles 006 , Lutz Warnke , Georgia Tech , Organizer: Justin Lanier
In Fall 2017 I will teach Random Discrete Structures', which is an advanced course in discrete probability and probabilistic combinatorics. The goal of this informal lecture is to give a brief outline of the topics we intend to cover in this course. Buzz-words include Algorithmic Local Locasz Lemma, Concentration Inequalities, Differential Equation Method, Interpolation method and Advanced Second Moment Method.
Wednesday, April 12, 2017 - 12:05 , Location: Skiles 006 , Jen Hom , Georgia Tech , Organizer: Justin Lanier
Defined in the early 2000's by Ozsvath and Szabo, Heegaard Floer homology is a package of invariants for three-manifolds, as well as knots inside of them. In this talk, we will describe how work from Poul Heegaard's 1898 PhD thesis, namely the idea of a Heegaard splitting, relates to the definition of this invariant. We will also provide examples of the kinds of questions that Heegaard Floer homology can answer. These ideas will be the subject of the topics course that I am teaching in Fall 2017.
Wednesday, April 5, 2017 - 12:05 , Location: Skiles 006 , Chi Ho Yuen , Georgia Tech , Organizer: Justin Lanier
I will continue the discussion on the group actions of the graph Jacobian on the set of spanning trees. After reviewing the basic definitions, I will explain how polyhedral geometry leads to a new family of such actions. These actions can be described combinatorially, but proving that they are simply transitive uses geometry in an essential way. If time permits, I will also explain the following surprising connection: the canonical group action for a plane graph (via rotor-routing or Bernardi process) is related to the canonical tropical geometric structure of its dual graph. This is joint work with Spencer Backman and Matt Baker.
Wednesday, March 15, 2017 - 12:05 , Location: Skiles 006 , Matt Baker , Georgia Tech , Organizer: Justin Lanier
Every graph G has canonically associated to a finite abelian group called the Jacobian group.  The cardinality of this group is the number of spanning trees in G.  If G is planar, the Jacobian group admits a natural simply transitive action on the set of spanning trees.  More generally, for any graph G one can define a whole family of (non-canonical) simply transitive group actions.  The analysis of such group actions involves ideas from tropical geometry. Part of this talk is based on joint work with Yao Wang, and part is based on joint work with Spencer Backman and Chi Ho Yuen.
Wednesday, February 22, 2017 - 12:00 , Location: Skiles 006 , Hua Xu , Gimmie Games , Organizer: Timothy Duff
In this talk, we will have an overview of: the Gaming Industry, specifically on the Video Slot Machine segment; the top manufactures in the world; the game design studio Gimmie Games, who we are, what we do; what is the process of making a video slot game; what is the basic structure of the math model of a slot game; current strong math models in the market; what is the roll of a game designer in the game development process; the skill set needed to be a successful Game Designer. Only basic probability knowledge is required for this talk.
Wednesday, January 18, 2017 - 12:00 , Location: Skiles 006 , , Georgia Institute of Technology , Organizer: Timothy Duff
On the two-dimensional square grid, remove each nearest-neighbor edge independently with probability 1/2 and consider the graph induced by the remaining edges. What is the structure of its connected components? It is a famous theorem of Kesten that 1/2 is the `critical value.'' In other words, if we remove edges with probability p \in [0,1], then for p < 1/2, there is an infinite component remaining, and for p > 1/2, there is no infinite component remaining. We will describe some of the differences in these phases in terms of crossings of large boxes: for p < 1/2, there are relatively straight crossings of large boxes, for p = 1/2, there are crossings, but they are very circuitous, and for p > 1/2, there are no crossings.
Wednesday, November 30, 2016 - 12:00 , Location: Skiles 006 , , Georgia Institute of Technology , Organizer: Timothy Duff
I will start with a brief presentation of the Probability activities in SOM. I will continue by presenting results obtained in SOM, over the past ten years, answering long standing questions insequences comparison.
Wednesday, November 16, 2016 - 12:00 , Location: Skiles 006 , , Georgia Institute of Technology , Organizer: Timothy Duff
A matroid is a combinatorial abstraction of an independence structure, such as linear independence among vectors and cycle-free-ness among edges of a graph.  An algebraic variety is a solution set of a system of polynomial equations, and it has a polyhedral shadow called a tropical variety.  An irreducible algebraic variety gives rise to a matroid via algebraic independence in its coordinate ring.  In this talk I will show that the tropical variety is compatible with the algebraic matroid structure.  I will also discuss some open problems on algebraic matroids and how they behave under operations on tropical varieties.