Prior to that, he was a junior researcher at the Institute for the Management of Information Systems of the "Athena" Research Center in Athens, Greece since 2009. During 2009-2011, he was a Marie Curie fellow at the Hong Kong University of Science and Technology (HKUST). He finished his PhD in Computer Engineering in 2008 under the supervision of professor T. Sellis at the National Technical University of Athens (NTUA), his MSc in Computer Science in 2004 at the University of Southern California (USC), and his Dipl.Ing. in Computer Engineering in 2001 at NTUA.