This award is made as part of the FY 2016 Mathematical Sciences Postdoctoral Research Fellowships Program. Each of the fellowships supports a research and training project at a host institution in the mathematical sciences, including applications to other disciplines, under the mentorship of a sponsoring scientist. The title of the project for this fellowship to Jason Xu is ?Statistical Analysis of Partially Observed Interacting Particle Systems.? The host institution for the fellowship is the University of California-Los Angeles, and the sponsoring scientist is Kenneth Lange.