| 1999- | School of Computer Science, University of Oklahoma, Norman, Oklahoma, Professor |
| 1999- | INDEC Systems, Capitola, California, Consulting Member of Technical Staff |
| 1997-1999 | Eclipse International, Mountain View, California, Senior Member of Technical Staff |
| 1994-1997 | School of Computer Science, University of Oklahoma, Norman, Oklahoma, Director and Professor |
| 1982-1994 | Amoco Production Company, Business Processes Reengineering, Houston (1993-1994), Research Supervisor, Tulsa Research Center (1982-1993) |
| 1988-1992 | Department of Mathematical and Computer Sciences, University of Tulsa, Tulsa, Oklahoma, Adjunct Professor |
| 1970-1982 | Department of Computer Science, Colorado State University, Fort Collins, Colorado, Professor( 1981-1982), Associate Professor (1975-1981), Assistant Professor (1970-1975) |
Software Engineering I and II, concentrates on software engineering processes, design, and quality, integrates the use of mechanical logic into the practice of software design and implementation, leading to software with correctness properties known to a mathematical certainty, course development supported by a two-year grant from the National Science Foundation, working in collaboration with Matthias Felleisen at Northeastern University, who is supported by a separate, concurrent grant
Faculty advisor for Programming Competition Team, which participates annually in the ACM International Programming Contest, 1994-1997, 2007 (won South Central Region 1996, team then went on to the top-level, international competition)
Advisor for numerous undergraduate honors theses, MS theses, and exchange student projects