1974-75 Post Doctoral Fellow, Dalhousie
1975-76 Lecturer and Research Associate, Dalhousie
1976-80 Assistant Professor, Dalhousie
1980-82 Associate Professor with Tenure (On Leave), Dalhousie
1980-81 Assistant Professor, Carnegie-Mellon University
1981-82 Associate Professor, Carnegie-Mellon University
1982-84 Associate Professor, Dalhousie University
1984/03-1993 Full Professor, Dalhousie University
1985 (3/1-7/31) French National Fellowship, Limoges, Prof Invité
1986 (1/1-7/31) Distinguished Visiting Professor, Centre de Récherches Mathématiques, Univ. of Montreal
1987-88 Senior Killam Fellow, Dalhousie University
1988 (6/1-9/30) Australian Research Grant Council Fellowship, ANU/Newcastle (offered for year)
1990 (5/1-6/30) Visitor at Technion (during term of specialization on Nonlinear Analysis)
1991 (4/1-5/30) French National Fellowship, Limoges, Prof Invité
1991-93 Professor, Dept of Combinatorics and Optimization, Waterloo on leave from Dalhousie.
1993/06-98/09 Shrum Professor of Science, Department of Mathematics and Statistics, Simon Fraser University
1993-96 Adjunct Professor, Department of Mathematics, Statistics and Computing, Dalhousie
1994-2006 Associate Member, School of Computer Science, Simon Fraser University
1994-2000 Member, Institute for Applied Algorithms & Optimization, Simon Fraser University
1997 Offered and ultimately declined position of Dean of Faculty of Mathematics, University of Waterloo, Ontario, Canada.
1998-2004 Gordon M. Shrum Professor of Science, Departments of Mathematics and Statistics, Simon Fraser University.
2001-03/12 Canada Research Chair in Information Technology at Simon Fraser University.
2002-03/11 Distinguished NewMIC Fellow, New Media Innovation Centre, Vancouver.
2004/01- Distinguished Research Adjunct Professor, Department of Mathematics, Simon Fraser University.
2004/01-2009/06 Research Professor, Faculty of Computer Science, Dalhousie University.
2004-2009 Canada Research Chair in Collaborative Technology at Dalhousie University.
2009- Laureate Professor, School of Mathematical and Physical Sciences, University of Newcastle, NSW, Australia.
2009/07-2014/06 Adjunct appointments at Dalhousie University, Canada in both the Faculty of Computer Science and the Department of Mathematics & Statistics.
2011-2013 Distinguished Professor, King Abdulaziz University, Jeddah, Saudi Arabia.
2016 The Distinguished Scholar in Residence (April-July), Western University, London Ontario, Canada.
2013- Adjunct Professor, Department of Economics, Chiang Mai University, Thailand.