· June 1973 - July 1976. Reserch student giving tutorials and lectures to undergraduates at Bradford University (UK), in Fortran, Basic, Algol 60, Algol 68 and System Analysis.
· September 1976 - June 1978. Lecturer at Al-Fateh University in Tripoli, Libya, teaching Introduction to Computer Science, Data Structures, Data Processing, Programming Languages and System Software.
· October 1981 - April 1984. Visiting Scientist with the Department of Computer Engineering at Patras Hellas (Introduction to Computers, Fortran, Logical Design, System Programming).
· April 1987 - Febr. 1991. Assistant Professor with the Department of Computer Engineering at Patras University (Software Engineering, Compiler Design, Operating Systems).
· February 1991 - March 1997. Associate Professor with the Department of Mathematics, Sector of Applied Mathematics and Informatics, University of Patras (Software Engineering, Compiler Design).
. March 1997-Today. Professor of Computer Science with the Department of Mathematics, Division of Computational Mathematics and Informatics, University of Patras.
· September 91- August 2001. Head of the Computational Mathematics and Informatics Section within the Department of Mathematics of Patras University.