C. Bekas has moved

Scientific Computing, Numerical Linear Algebra, Distributed Computing and OpenMP Parallel Computation, Multithreaded Libraries, Problem Solving Environments

Research top

Post-doc Research

· Domain decomposition methods for large scale eigenvalue problems, Automated Multilevel Substructuring

· Numerical methods for mining of high dimensional data

· Parallel preconditioned linear solvers

· Multithreaded libraries for parallel numerical linear algebra

· Problem solving environments for scientific computation

Ph.D. Research

· Algorithms for the efficient and parallel computation of matrix Pseudospectra

· Iterative Methods for the computation of a few singular values of large and sparse matrices

· MATLAB, MPI based parallel toolbox for the computation of matrix Pseudospectra

Education top

University of Patras, Greece, 1993-2003

· PhD in Computer Science, June 2003.

Thesis title: "Efficient Computation of Matrix Pseudospectra, Methods and Software Tools (in Greek)"

Supervisor: Prof. E. Gallopoulos.

· Master in Computer Engineering and Informatics, May 2001

Thesis title: "Towards the Efficient Computation of Matrix Pseudospectra"

Supervisor: Prof. E. Gallopoulos

· Diploma in Computer Engineering & Informatics, July 1998

Awards, Distinctions top

Bodossaki Foundation Graduate Fellowship, 1999 - 2003
(extension of 6 months beyond maximum of 3 years).
Technical Chamber of Greece award for excellence, 2000.
Computer Engineering & Informatics Dept. Graduate Fellowship
(awarded to first year graduate students only) 1998-1999.

Publications top

Submitted

C. Bekas, E. Gallopoulos and V. Simoncini: “Pseudospectra Computation of Large Matrices”. Jan. 2004. (link to article) (software))

C. Bekas, E. Kokiopoulou and Y. Saad. "Polynomial filtered Lanczos iterations with applications in Density Functional Theory ". July 2005. (link to article) MSI Tech. Report 2005-xxx

Refereed Journal Papers

1. C. Bekas and E. Gallopoulos. "Cobra: Parallel Path Following for Computing the Matrix Pseudospectrum." Parallel Computing, v. 27, pp. 1879-1896, 2001 ( link to article)

2. C. Bekas and E. Gallopoulos. "Parallel Computation of Pseudospectra by Fast Descent" Parallel Computing, v. 28, pp. 223-242, 2002 (link to article)

3. E. Kokiopoulou, C. Bekas and E. Gallopoulos, "Computing Smallest Singular Triplets with Implicitly Restarted Lanczos Bidiagonalization". J. Appl. Num. Mathematics, 49(1), 2004, pages 39-61. (link to article)

4. C. Bekas, E. Kokiopoulou and E. Gallopoulos, "The Design of a Distributed PSE for Computing Pseudospectra". Future Generation Computer Systems, 21(6), pages 930-941, Elsevier, 2005 (link to article )

5. C. Bekas and Y. Saad: “Computation of Smallest Eigenvalues using Spectral Schur Complements”. To appear in SIAM J. Scient. Comp., 2005 (link to article )

6. C. Bekas, Y. Saad, M. Tiago and J. Chelikowsky. "Computing Charge Densities with Partially Reorthogonalized Lanczos". March 2005. To appear in Comp. Phys. Comm. (link to article)

7. C. Bekas, E. Kokiopoulou and Y. Saad . "An estimator for the diagonal of a matrix". Febr. 2006. To appear in Appl. Num. Math. (link to article)

Refereed Conference Papers

1. C. Bekas, E. Kokiopoulou, I. Koutis and E. Gallopoulos. "Towards the effective parallel computation of matrix pseudospectra," ACM, ICS 2001, Sorrento, Italy, pp 261-270. (link to article)

2. C. Bekas, E. Kokiopoulou, E. Gallopoulos and V. Simoncini: "Parallel Computation of Pseudospectra Using Transfer Functions on a MATLAB-MPI Cluster Platform", 9th EuroPVM/MPI, September 29th - October 2nd, 2002, Linz Austria (link to article)

Invited Conference Papers

1. C. Bekas, E. Kokiopoulou, I. Koutis and E. Gallopoulos. "Developing a Cluster Based MATLAB Environment for Computing Pseudospectra", GRACM Congress on Computational Mechanics, June 27-29, 2002, Patras , Greece

Conference Presentations (refereed)

1. C. Bekas and E. Gallopoulos. "Cobra: A hybrid method for computing the matrix pseudospectrum." In Proc. Copper Mountain Conference on Iterative Methods, vol. 1 April, 1998

2. C. Bekas, O. Bertrand, E. Gallopoulos and B. Philippe. "New Continuation Methods for the Computation of the matrix Pseudospectrum" HERCMA 98, Athens University of Economics and Business.

3. C. Bekas, E. Gallopoulos and V. Simoncini. "On the Computational Effectiveness of Transfer Function Approximations to the Matrix Pseudospectrum". In Proc. Copper Mountain Conference on Iterative Methods, Vol. ΙΙ, April 2000

4. C. Bekas, E. Gallopoulos. "Computing Pseudospectra by Fast Descent". PMAA 2000, August 18-21, 2000, Neuchatel, Switzerland.

5. C. Bekas, I. Koutis, E. Kokiopoulou, A. Sidiropoulos and E. Gallopoulos. "Parallel Methods for the Computation of Matrix Pseudospectra", 5th IMACS Conference on Iterative Methods in Scientific Computing, May 28-31, 2001

6. I. Koutis , C. Bekas, E. Kokiopoulou and E. Gallopoulos. "Advances in the Theory and Computation of Pseudospectra", SIAM Annual Meeting, July 8-12, 2002, Philadephia, USA.

7. E. Kokiopoulou, C. Bekas and E. Gallopoulos, "Implicitly Restarted Harmonic Lanczos Bidiagonalization for the Computation of the Smallest Singular Values of Large Sparse Matrices", 2nd International Workshop on Parallel Matrix Algorithms and Applications (PMAA'02), 9-10 November 2002, Neuchatel, Switzerland

8. C. Bekas, E. Gallopoulos and V. Simoncini, "Transfer Functions and Path Following for Computing Pseudospectra". Extended abstract in the (electronic) Proc. SIAM Conf. in Applied Linear Algebra, July 2003.

9. C. Bekas and Y. Saad. "AMLS and Spectral Schur Complements ". In Proc. Copper Mountain Conference on Iterative Methods, March, 2004.

10. C. Bekas K. Petrakos and E. Gallopoulos. "Towards Computing Pseudospectra of Parameter Dependent Matrices ". In Proc. Copper Mountain Conference on Iterative Methods, March, 2004.

Invited Talks

AMLS, Spectral Schur Complements and Iterative Computation of Eigenvalues, Scientific Computing Seminar, Lawrence Berkeley National Laboratory, Jan. 18, 2005. (power point)
Large Scale Computational Challenges in Materials Science, Computer Science Department Colloquium, The College of William and Mary, Jan 28, 2005. (power point)

Research Projects top

January 1997 - December 1998, European Scientific Project STABLE "Study of Stability of Physical Systems Using Parallel Computers"
Partners: IRISA Rennes, IMN Novosibirsk, MISAS Bratislava, CLPP Sofia, LHPCA Patras, LIMSI Orsay
January 2000 - August 2001, Greek Secretariat of Research and Development, PENED -97 "Developing a new Generation of simulators for Chemical Reactors" Partners: LHPCA Patras,Chemical Eng. NTUA, Math. Depart. University of Crete

Professional Experience top

· System Administrator: University of Patras, Origin 2000 parallel system

· Member of Technical Chamber of Greece, SIAM (Linear Algebra, Supercomputing)

Foreign Languages top

Cambridge, Certificate of Proficiency in English
German, basic

Last Revision: May 2005