| July 2002 - present | Queen's Research Chair in Biomedical Computing |
| School of Computing | |
| Queen's University | |
| September 2003 - April 2004 | Elected Visiting Research Fellow |
| Institute of Advanced Studies | |
| University of Bologna, Italy | |
| July 1997 - June 2002 | Head |
| Department of Computing and Information Science | |
| Queen's University | |
| March 1995 - May 1995 | Visiting Scientist |
| Cambridge Crystallographic Data Center | |
| Cambridge University, England | |
| July 1993 - June 1997 | Professor |
| Department of Computing and Information Science | |
| Queen's University | |
| July 1986 - 1993 | Associate Professor |
| (tenured 1987) | Department of Computing and Information Science |
| Queen's University | |
| 1981 - 1986 | Assistant Professor |
| Department of Computing and Information Science | |
| Queen's University | |
| 1974 - 1980 | Research Assistant, Teaching Assistant and Lecturer |
| Department of Computer Science | |
| University of Waterloo |