1. Institute of Informatics and Telecommunications, NCSR 'Demokritos', Greece
2. Institute of Informatics and Telecommunications, NCSR 'Demokritos', Greece and Department of Informatics and Telecommunications, National and Kapodistrian University of Athens, Greece
3. Department of Maritime Studies, University of Piraeus, Greece and Institute of Informatics and Telecommunications, NCSR 'Demokritos', Greece