He received his Ph.D. degree in 2000 from the Department of Computer Science, UCLA. His research areas include CSCW, Middleware, Programming Languages, Logic Programming, and Database Systems, with a focus on collaboration modeling and infrastructure support. He chaired the second international workshop on collaborative editing systems in the CSCW'00 conference. He is on the papers committee of CSCW'02. He received an NSF CAREER award in 2003. His PhD thesis developed COCA which is a framework for modeling synchronous collaboration. His recent work includes end-user programming of collaboration protocols and developing collaborative editing systems through transparent sharing of familiar single-user editors.