1994 - Present: Associate Professor, Department of Computer Science, University of Rochester.
1988 - 1994: Assistant Professor, Department of Computer Science, University of Rochester.
1985 - 1988: Research Assistant, University of Maryland, Computer Vision Laboratory. Research on computer vision and visual navigation.
1984 - 1985: Research assistant, University of Maryland, Center for Automation Research. Developed data structures and software for Geographic Information System based on hierarchical data structures.
1983 - 1984: Teaching assistant, University of Maryland, Department of Computer Science.
1981 - 1982: Teaching assistant, Dartmouth College, Department of Physics.
1980: Research assistant under NSF Undergraduate Research Participation Program at Rensselaer Polytechnic Institute, Department of Physics and Astronomy. Worked with computer models for radiative transport in astronomical infrared sources.