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Seminars

Applied Math Seminars

This seminar series is co-coordinated by Jong Soo Lee (JongSoo_Lee@uml.edu), Hung Phan (Hung_Phan@uml.edu) and Min Hyung Cho (MinHyung_Cho@uml.edu). Contact any of them if you would like to speak as part of this seminar.


Fall 2019 Seminar Series

Stochastic superparameterization through local data generation.

  • Yoonsang Lee, Department of Mathematics, Dartmouth College
  • Wednesday, September 11, 3:30 p.m., Olney 430

Stochastic superparameterization is a class of multiscale methods that approximate large-scale dynamics of complex dynamical systems such as turbulent flows. Unresolved sub-grid scales are modeled by a cheap but robust stochastic system that mimics the true dynamics of the sub-grid scales, which is crucial to model non-trivial and non-equilibrium dynamics. In this talk, we propose a numerical procedure to estimate the modeling parameters, which avoids the use of climatological data.

Hardness results for sampling connected graph partitions with applications to redistricting

  • Daryl Deford, MIT
  • Wednesday, September 18, 4 p.m., Olney 430

The problem of constructing ”fair'' political districts and the related problem of detecting intentional gerrymandering has received a significant amount of attention in recent years. A key problem in this area is determining the expected properties of a representative districting plan as a function of the input geographic and demographic data. A natural approach is to generate a comparison ensemble of plans using MCMC and I will present successful applications of this approach in both court cases and legislative reform efforts. However, our recent work has demonstrated that the commonly used boundary-node flip proposal can mix poorly on real-world examples. In this talk, I will present some new proposal distributions for this setting and discuss some related open problems concerning mixing times and spanning trees. I will also discuss some generic hardness results for sampling problems on partitions of planar graphs.

Topic to be determined

  • Zheng Chen, Department of Mathematics, UMass Dartmouth
  • Thursday, October 3, 2 p.m., Olney 430

Topic to be determined

  • Samuel Isaacson, Department of Mathematics and Statistics, Boston University
  • Wednesday, November 6, 4 p.m., Olney 430