| Date | Place | Country | Occasion |
| November 16, 2011 | Utrecht University | Netherlands | Stochastics and Numerics Seminar |
| November 9, 2011 | KU Leuven | Belgium | Doctoral seminar |
| August 23, 2011 | Braunschweig | Germany | ILAS 2011 (Invited plenary) |
| July 16, 2010 | TU Chemnitz | Germany | Invitation Peter Benner and Patrick Kuerschner |
| June 28, 2010 | Berlin | Germany | 8th International Workshop on Accurate Solution of Eigenvalue Problems |
| June 17, 2010 | Lund | Sweden | BIT 50 (Invited plenary) |
| June 2, 2010 | Luminy | France | Inverse Problems: Computation and Applications (IPCA10) |
| April 23, 2010 | Utrecht | Netherlands | Dutch Math Congress 2010 |
| December 17, 2009 | Düsseldorf | Germany | Invitation Marlis Hochbruck |
| December 11, 2009 | Valencia | Spain | Invitation of Jose Roman |
| April 24, 2009 | Eindhoven | Netherlands | Voorjaarsbijeenkomst Werkgemeenschap Scientific Computing, |
| July 4, 2008 | Venice | Italy | WCCM8 / ECCOMAS 2008 |
| June 11, 2008 | Dubrovnik | Croatia | 7th International Workshop on Accurate Solution of Eigenvalue Problems |
| June 5, 2008 | Zeuthen | Germany | Householder Symposium XVII |
| May 22, 2008 | Rutherford Appleton Laboratory | England | Invitation of Jennifer Scott and Sue Dollar |
| March 12, 2008 | Ljubljana | Slovenia | Invitation Bor Plestenjak |
| June 19, 2007 | TU Braunschweig | Belgium | Invitation Heike Fassbender and Elias Jarlebring |
| June 4, 2007 | TU Freiberg | Germany | Invitation Michael Eiermann and Oliver Ernst |
| May 2, 2007 | Universite Catholique Louvain-la-Neuve | Belgium | Invitation Pierre-Antoine Absil |
| March 29, 2007 | Bedlewo | Poland | Workshop on Structured Perturbations, and Distance Problems in Matrix Computations |
| March 15, 2007 | Antwerpen University | Belgium | Invitation Karel in 't Hout |
| January 17, 2007 | KU Leuven | Belgium | Invitation Karl Meerbergen |
| July 26, 2006 | Düsseldorf | Germany | Joint GAMM/SIAM Conference on Applied Linear Algebra (2nd talk) |
| July 24, 2006 | Düsseldorf | Germany | Joint GAMM/SIAM Conference on Applied Linear Algebra (1st talk) |
| July 22, 2006 | Utrecht | Netherlands | Symposium in honor of Henk Van der Vorst |
| July 18, 2006 | Amsterdam | Netherlands | 13th International Linear Algebra Society conference |
| July 15, 2006 | Bremen | Germany | 8th Workshop on numerical ranges and numerical radii |
| May 22, 2006 | Penn State | USA | 6th International Workshop on Accurate Solution of Eigenvalue Problems |
| March 28, 2006 | Berlin | Germany | 77th GAMM meeting |
| March 22, 2006 | Eindhoven | Netherlands | Invitation Bob Mattheij |
| February 7, 2006 | Düsseldorf | Germany | Workshop exponential integrators |
| September 20, 2005 | Leiden | Netherlands | Workshop Model order reduction, coupled problems and optimization |
| July 29, 2005 | Birmingham | UK | Invitation Andreas Frommer |
| June 28, 2005 | Wuppertal | Germany | Invitation Roy Mathias |
| May 23, 2005 | Seven Springs | Pennsylvania | Householder Symposium XVI |
| May 5, 2005 | Toronto | Canada | 7th IMACS International Symposium on Iterative Methods in Scientific Computing |
| April 29, 2005 | Virginia Tech | USA | Invitation Chris Beattie |
| July 9, 2004 | Düsseldorf | Germany | Invitation Marlis Hochbruck |
| July 5, 2004 | Hamburg | Germany | Invitation Heinrich Voss |
| July 3, 2004 | Hagen | Germany | GAMM Workshop on Numerical Linear Algebra in Systems and Control |
| June 29, 2004 | Hagen | Germany | V International Workshop on Accurate Solution of Eigenvalue Problems |
| January 22, 2004 | Kent, Ohio | USA | Invitation Lothar Reichel |
| June 17, 2003 | Montreal | Canada | 2003 SIAM annual meeting |
| May 15, 2003 | Utrecht | Netherlands | General colloquium |
| May 7, 2003 | Zuerich | Switzerland | Invitation Peter Arbenz |
| March 29, 2003 | Denver, Colorado | USA | 6th IMACS International Symposium on Iterative Methods in Scientific Computing |
| January 31, 2003 | Cleveland, Ohio | USA | Invitation Daniela Calvetti |
| August 5, 2002 | Milovy | Czech Republic | Computational Linear Algebra with Applications |
| June 27, 2002 | Split | Croatia | 4th International Workshop on Accurate Solution of Eigenvalue Problems |
| June 18, 2002 | Edinburgh | Scotland | Householder Symposium XV |
| May 8, 2002 | Ljubljana | Slovenia | Invitation Bor Plestenjak |
| March 28, 2002 | Copper Mountain, Colorado | USA | 7th Copper Mountain Conference for Iterative Methods |
| May 28, 2001 | Düsseldorf | Germany | Invitation Marlis Hochbruck |
| February 8, 2001 | Dresden | Germany | Invitation Hubert Schwetlick |
| October 25, 2000 | Raleigh, North-Carolina | USA | 7th SIAM Conference on Applied Linear Algebra |
| July 5, 2000 | Hagen | Germany | 3rd International Workshop on Accurate Solution of Eigenvalue Problems |
| April 27, 2000 | Maastricht | Netherlands | 36th Dutch Mathematical Congress |
| April 6, 2000 | Copper Mountain, Colorado | USA | 6th Copper Mountain Conference for Iterative Methods |