- Keynote talk, EASIAM 2012, Taipei, Taiwan
- Invited talk, DOE Applied Math Workshop, Reston, VI, October 2011
- Plenary talk,
MSDL Conference on Modelling Storage in Deep Layers, Schwetzingen, October, 2011
- Plenary talk, Simulation of Flow in Porous Media and Applications in Waste Management and CO2 Sequestration, October 2011
- Plenary talk,
Splitting and Multiscale Methods for Computational PDEs, Baylor University,  September 2011
- Invited talk,  Stochastic Modeling and Uncertainty Quantification, Rio de Janeiro, August, 2011
- Colloquim talk, College de France, June 2011
- Invited 25 min minisymposium talk, Applied Inverse Problem Conferencem Texas A&M University, May 2011
- Invited 25 min minisymposium talk, Interpore 2011, Bordeaux, France, April, 2011
- Invited 1 hour talk,
MATCH Symposium on Analytical and Numerical Methods for Multiscale Systems, Heidelberg, February, 2011
- Invited 1 hour talk, Highly Oscillatory Problems, Newton Institute, Cambridge 2011
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Plenary talk, SIAM  Geosciences, 2011
- Invited 1 hour talk, Felix Klein Summer School, Kaiserslautern, Germany, September 2010
- Peaceman Lecture on Numerical Mathematics, Rice University, Feb., 2010
- Invited talk, Novel multi-scale methods for multi-phase porous media flow, Edinburgh, 2010
- Invited talk, International conference on sparse representation of multiscale data and images, Singapore, December, 2009
-Plenary talk, Multiscale methods for porous media flows, Qingdao, China, Nov. 2009
- Colloquium, Caltech, Nov., 2009
- Invited talk, HPCA 2009, Shanghai, Aug., 2009
- Invited talk, LSSC, Sozopol, Bulgaria, June 2009

- Invited talk,  Tenth Workshop in Partial Differential Equations, August 6-10, IMPA, Rio de Janeiro, Brazil, 2007

- Invited talk, ``Upscaling workshop'', University of Bergen and CIPR, Bergen,  Norway, April 20-22.

- Invited talk,  LMS-EPSRC Short Course, University of Warwick, UK, 15th-20th April 2007.

- Invited talk, ``The Theory of Highly Oscillatory Problems'', Newton Institute, Cambridge, March 26-30.

- Invited talk, International Workshop on Multiscale Analysis and Applications, Singapore, December, 2006

- Invited talk, Multiscale Problems: Modeling, Adaptive Discretization, Stabilization, Solvers Cortona, Italy, September 18-22, 2006

- Talk in summer school, Summer School GDR-CNRS GRIP on Multiscale Transport Phenomena, Centre International de Sejours, Seix, France, June 11-18, 2006

- Invited talk (three 1 hour lectures) Workshop on numerical, mathematical and modeling analysis related to fluid dynamics in hydrogen fuel cells, University of Ottawa, May 9-12, 2006

- Talk in summer school (three 1.5 hours lectures), Summer School GDR-CNRS GRIP on Multiscale Transport Phenomena, Centre International de Sejours, Seix, France, June 11-18, 2006


-  Invited talk (50 minutes), Ninth Workshop in Partial Differential Equations, July 18-25, IMPA, Rio de Janeiro, Brazil, 2005. Title of the talk: "Multiscale modeling and simulations of porous media flows"


- Invited talk (50 min), "Integrative Multiscale Modeling and Simulation in Materials Science, Fluids and Environmental Science" from May 10-13, 2005, in CRM,  Universite de Montreal, Canada, Title of the talk: "Multiscale finite element methods for flows in heterogeneous porous media"

- Invited talk (50 min), "Workshop on Multiscale Finite Element Methods" from May 5-7, 2005, in UT Austin, "Multiscale finite element methods for nonlinear partial differential equations"
       

- Invited talk, "Upscaling og geocellular models in heterogeneous porous media", IMA Workshop in Grand Challenges in Multiscale modeling and simulation, November, 18-20, 2004

- Keynote Speaker, ``Multiscale modeling, and applications in fluid flow and material science'', October 18-20, 2004, Oslo, Norway. Title of the talk: ``Multiscale finite element methods for nonlinear problems and their applications''

-  Invited talk (50 min), Eights Workshop in Partial Differential Equations, July 21-25, IMPA, Rio de Janeiro, Brazil, 2003. Title of the talk: "Homogenization and numerical homogenization of nonlinear parabolic equations"


- Many minisymposia invited talks and organized many sessions (minisymposia) in major conferences