Yunfeng graduated in 2018 with his PhD under my direction, with Bala Krishnamoorthy as his co-advisor. His dissertation was focused on the use of the flat norm as a tool to get median shapes. The main paper, the result of a collaboration between Yunfeng, Bala and myself with important contributions from two others can be found here. After graduating he was hired at the technical lead in data science at EMSI in Moscow, Idaho. (Though that was not his official title, it was what he was actually doing.) In Fall 2019, he accepted an offer to join a research team at Amazon, in Seattle, which is where he has worked since there.
