1965–1967 Scientific Officer, Applied Mathematics Division, Dept of Scientific and Industrial Research (DSIR), Wellington, New Zealand
1967–1972 Research Assistant and Teaching Assistant, Computer Science Dept, Stanford University; Graduate Study Leave (part salary) from DSIR
1972–1974 Scientific Officer, Applied Mathematics Division, DSIR, Wellington, New Zealand
1975–1976 Research Associate, Systems Optimization Laboratory, Dept of Operations Research, Stanford University
1977–1978 Scientist, Applied Mathematics Division, DSIR, Wellington, New Zealand
1979–1987 Senior Research Associate, Systems Optimization Laboratory, Dept of Operations Research, Stanford University
1987–2016 Professor (Research), Systems Optimization Laboratory, Depts of OR, EESOR, and Management Science and Engineering, Stanford University
2017–present Professor (Research) Emeritus, recalled to active duty, Management Science and Engineering, Stanford University
1972 (Oct) Visiting Research Fellow, Division of Numerical Analysis and Computing, National Physical Laboratory, Teddington, England
1981 (May–Jun) Visiting Scholar, Dept of Mathematics, University of Link¨oping, Link¨oping, Sweden
1990 (Jul–Aug) Visiting Fellow, Dept of Operations Research, University of Canterbury, Christchurch, New Zealand
1995–96 Visiting Scholar, IBM Almaden Research Center (2 days/week)
1998 (Jul–Oct) Visiting Professor, Dept of Engineering Science, University of Auckland, New Zealand (taught Master’s class on Nonlinear Optimization)
1999 (Aug) Visiting Professor, Institute of Mathematical Modelling (IMM), Technical University of Denmark, Lyngby, Denmark
2000 (Jul) Visiting Professor, Dept of Mathematics and Physics, M¨alardalen University, V¨aster˚as, Sweden
2001 (Aug) Visiting Professor, IMM, Technical University of Denmark