2016-2019 Division Director, Computer and Network Systems, Directorate for Computer and Information Science and Engineering, National Science Foundation
2012–2014 Interim Director, Center for Visualization and Virtual Environments, University of Kentucky
2007–2013 Chairman, Computer Science Department, University of Kentucky
2007–present Professor, Computer Science, University of Kentucky
2004–2005 Acting President, Lumenware, LLC, Lexington, KY (Sabbatical)
1998–2007 Associate Professor, Computer Science, University of Kentucky
1991–98 Assistant Professor, College of Computing, Georgia Tech
1984–91 Research Fellow/Assistant, University of Texas at Austin
1979–84 Member of Technical Staff, Bell Telephone Laboratories, Holmdel, NJ
Ph.D. 1991 University of Texas at Austin Computer Sciences
M.S. 1980 Stanford University Computer Science
S.B. 1979 M. I. T. Computer Science and Engineering
Next-Generation Computer Network Protocols and Architectures
Active Networks
Network Security
Formal Methods