Prior to July 1998, he was a faculty member at the Electrical and Computer Engineering department. His research interests are information assurance, computer security, fault diagnosis, fault tolerant computing, and VLSI Testing. He has authored or coauthored more than 150 articles in refereed journals and conferences in these areas. His current projects involve insider threat modeling, intrusion detection, security in wireless networks, and protection against Internet attacks. His research has been supported by the National Science Foundation, Rome Laboratory, the U.S. Air Force Office of Scientific Research, National Security Agency, IBM, and Cisco.