Director of ICCS (ΕΠΙΣΕΥ) – Institute of Computer and Communication Systems os NTUA since 2009.
Professor Emeritus, School of Electrical and Computer Engineering, National Technical University of Athens.
Member of the Scientific Council of the Hellenic Parliament since 1987
He has served as Professor in the Department of Computer Science, University of Crete (1987-93) and Associate Professor in the Business School of New York University (Department of Information Systems) (1980-87). Director of the Institute of Informatics of the Foundation for Research and Technology Hellas (FORTH – ΙΤΕ), (1985-1991). Chairman of the Consultative Technical Council of The Ministry for Administrative Reform and Electronic Government (2013-2015). Vice-chair, School of Electrical and Computer Engineering, National Technical University of Athens (2006 – 2009). Director of the Knowledge and Data Base Laboratory at the National Technical University of Athens since 2008-2016. Chairman, Board of Directors of IDIKA, (1996-2003). Endowment Trustee of the Very Large Data Bases (VLDB) Foundation (1989 – 1995). Member of the Board of Directors (consultancy Body) of the European Commission for the Industrial Impact at a Pan-European level of the Research Projects for ESPRIT / IST (1993 – 1999). Member of the Scientific Committee for the Advancement of Sciences of the A. Onassis Foundation and the Foundation of Research and Technology Hellas (2000-2016).