• Southeastern Combinatorics Conference, 2022.
• SIAM Matrix Theory, 2020.
• AIM Workshop on Zero Forcing and Minimum Rank, 2016.
• Southeastern Combinatorics Conference, 2014.
• Hamilton Conference on Nonnegative Matrices, Maynooth, Ireland 2006
• MAA Regional meeting, Grand Junction, Colorado, 2006
• International Linear Algebra Society Meeting, Regina, Canada, 2005
• Haifa Matrix Theory meeting, Haifa, Israel, 2005
• Missouri Sectional MAA meeting, 2005
• SIAM Linear Algebra and Applications Meeting, Williamsburg, VA, 2003
• Kansas Sectional MAA meeting, Hays, KS, 2003
• Combinatorial Matrix Theory, Postech, S. Korea, 2002
• International Linear Algebra Society Meeting, Atlanta, GA, 2002
• Rocky Mountain Mathematics Consortium, Laramie, WY, 2002
• Algebraic Graph Theory, Int’l Centre for Mathematical Sciences, Edinburgh, Scotland, 2001
• Western Canada Linear Algebra Meeting, Winnipeg, Canada, 2000. Topology and Geometry
• Research Center of S. Korea, Kyungpook, 1995

Meetings co-organized

• UW-NCAR Days, University of Wyoming October 2018.
• Workshop on Zero Forcing and Minimum Rank, American Institute of Mathematics, 2016.
• Special session on Graphs and Matrices, Joint Math Meetings, 2016, 2017, 2018.
• Workshop on Spectral Graph and Combinatorial Matrix Theory, American Inst. of Math, 2006.
• Special Session on Combinatorial Matrix Theory, AMS Sectional meeting, Lincoln, 2005
• 2005 Brualdi-fest, Madison, Wisconsin,
• 2005 BIRS Workshop on Combinatorial Matrix Theory, Banff Canada,
• 2004 International Linear Algebra Society Conference, Coimbra, Portugal,
• 2004 Rocky Mountain Discrete Math Day,
• 2002 Rocky Mountain Regional MAA meeting, Laramie, WY,
• 2002 Minisymposium at ILAS Conference, Barcelona, Spain, 1999
• Minisymposium at Centennial PhD Conference, Madison, 1998
• AIM Workshop on Zero Forcing and Minimum Rank, 2016.
• Hamilton Conference on Nonnegative Matrices, Maynooth, Ireland 2006