- NSERC committee to evaluate research grants, 2012 - 2014
- Program Committees:
- co-chair, Symposium on Computational Geometry (SoCG) 2016
- co-chair, Graph Drawing 2015
- SODA (Symposium on Discrete Algorithms) 2012
- SoCG (Symposium on Computational Geometry) 2011, 2004, 1999
- GD (Graph Drawing) 2019, 2017, 2014, 2012, 2002, 1998, 1995
- ISAAC (International Symposium on Algorithms and Computation) 2008
- LATIN 2014
- CCCG (Canadian Conference on Computational Geometry) 2018, 2017, 2013, 2011, 2010, 2009, 2004, 2001, 2000, 1992
- IWOCA (International Workshop on Combinatorial Algorithms) 2011
- FWCG (Fall Workshop on Computational Geometry) 2009
- co-chair, CCCG (Canadian Conference on Computational Geometry) 1993