# MSCS Seminar Calendar

Monday August 7, 2017

**Statistics Seminar**

Semi-parametric method for non-ignorable missing in longitudinal data using refreshment samples

Dr. Lan Xue (Oregon State University)

3:00 PM in SEO 636

Missing data is one of the major methodological problems in longitudinal studies. It not only reduces the sample size, but also
can result in biased estimation and inference. It is crucial to correctly understand the missing mechanism and appropriately
incorporate it into the estimation and inference procedures. Traditional methods, such as the complete case analysis and imputation
methods, are designed to deal with missing data under unverifiable assumptions of MCAR and MAR. The purpose of this talk is to identify
and estimate missing mechanism parameters under the non-ignorable missing assumption utilizing the refreshment sample. In particular, we
propose a semi-parametric method to estimate the missing mechanism parameters by comparing the marginal density estimator using Hirano?s
two constraints (Hirano et al. 1998) along with additional information from the refreshment sample. Asymptotic properties of semi-parametric estimators are developed. Inference based on bootstrapping is proposed and verified through simulations.

Wednesday August 30, 2017

**Algebraic Geometry Seminar**

Schlesinger equations in positive characteristic

Daniel Litt (Columbia University)

4:00 PM in SEO 427

Let X be a complex manifold and E a vector bundle with flat connection on X. Then given a deformation of X, one obtains a canonical "isomonodromic" deformation of E, which, as the name suggests, preserves the monodromy of E. In the case X is the projective line minus a collection of points, these deformations are controlled by the Schlesinger equations. We define and study the analogous situation in positive characteristic.

Friday September 1, 2017

Monday September 11, 2017

Monday September 18, 2017

Friday September 22, 2017

Wednesday September 27, 2017

Friday October 13, 2017

Monday November 6, 2017

Monday November 13, 2017