Past Events
Scientific, Seminar
Scientific Computing, Applied and Industrial Mathematics (SCAIM) Seminar: Bas Peters
October 29, 2019
University of British Columbia
Different from most deep learning settings, we focus on the situation where we have only one or a few large-scale examples. We also assume that only partial labels are available. Examples include video segmentation and segmentation of 3D geophysical...
Scientific, Seminar
Lethbridge Number Theory and Combinatorics Seminar: Quanli Shen
October 28, 2019
University of Lethbridge
In this talk, I will talk about the fourth moment of quadratic Dirichlet L-functions. Under the generalized Riemann hypothesis, we showed an asymptotic formula for the fourth moment. Unconditionally, we established a precise lower bound.
Scientific, Distinguished Lecture
PIMS - UVictoria Public Lecture: Caroline Colijn
October 25, 2019
University of Victoria
New kinds of data are giving rise to exciting new opportunities in public health. The recent revolution in DNA sequencing means that for the first time, we can read the sequences of viruses and bacteria that cause human disease. This allows us to...
Scientific, Seminar
PIMS - AMI Seminar: Wenyuan Liao
October 25, 2019
University of Alberta
Recently, the optimal transport distance, or so-called Wasserstein distance has been introduced to full waveform inversion to compute the misfit between two seismograms. This measure has great potential to account for time and space shifts of events...
Scientific, Seminar
UBC Math Department Colloquium: Liam Watson
October 25, 2019
University of British Columbia
Mutation is a process that makes a non-trivial local change to a knot; the distinction between the resulting pair of knots is difficult to detect. I will present a vaguely historical account of why mutant pairs are difficult to distinguish. This will...
Scientific, Distinguished Lecture
PIMS - SFU Computational Mathematics Seminar: James Scott
October 25, 2019
Simon Fraser University
We consider the Dirichlet problem for a strongly-coupled nonlocal system of equations motivated by peridynamics, a model in continuum mechanics. The strain energy densities involve the magnitude of projected "directional" difference quotients of the...
Scientific, Distinguished Lecture
PIMS- UVictoria Distinguished Lecture: Caroline Colijn
October 24, 2019
University of Victoria
Improvements in sequencing technology mean that we have rich data on how infections evolve and spread. In this talk I will describe two settings where this calls for new mathematics. Trees -- in the sense of graphs with no cycles -- are a cornerstone...
Scientific, Seminar
Probability Seminar: Thomas Budzinski
October 23, 2019
University of British Columbia
What is the minimal possible diameter of a hyperbolic surface (i.e. with constant curvature equal to -1) of genus g? We will prove that it is asymptotic to log(g). While the lower bound follows from a simple volume growth argument, the upper bound is...
Scientific, Seminar
PIMS / AMI Seminar / IGR (Institute for Geophysical Research): Paul Williams
October 23, 2019
University of Alberta
The second-order centered (leapfrog) time-stepping scheme is commonly used in numerical models of weather and climate. The unstable computational mode is damped by applying a Robert–Asselin filter, which introduces first-order numerical errors...
Scientific, Seminar
PIMS - AMI Seminar: Hugo Lavenant
October 23, 2019
University of Alberta
Among modern numerical methods to solve the optimal transport problem, dynamical optimal transport (a.k.a. fluid dynamic formulation or Benamou-Brenier formulation) is one of the oldest: it consists in rewriting the problem in terms of convex...