1. Computer Science and Engineering Department, University of Ioannina, Ioannina, Greece
2. Department of Applied Informatics, University of Macedonia, Thessaloniki, Greece
3. Institute of Technology (TU Berlin), Berlin, Germany
4. Foundation for Research and Technology Hellas (FORTH), Heraklion, Greece
5. School of Electrical and Computer Engineering, Technical University of Crete, Chania, Greece
6. Computer Science Department, University of Cyprus, Nicosia, Cyprus
7. Berlin Institute of Technology (TU Berlin), Berlin, Germany
8. Truva Inc., Alpharetta, GA, USA