I'm currently working with Prof. R. Ravi on approximation algorithms for graphic TSP in bipartite graphs. Here's a link to a recent paper (as of September 3, 2013) proving a sub-4/3 approximation for k-regular bipartite graphs.
In the fall of 2012, I wrote a paper on pricing and queueing with Prof. Mor Harchol-Balter, Sherwin Doroudi, Christian Borgs, Jennifer Chayes, and Prof. Mustafa Akan. You can view a draft of this paper here.
You can email me at jkarp AT andrew.cmu.edu