1. DIANA-Lab, Department of Electrical and Computer Engineering, Univ. of Thessaly, 38221 Volos, Greece
2. Hellenic Pasteur Institute, 11521 Athens, Greece
3. Department of Computer Science and Biomedical Informatics, Univ. of Thessaly, 351 31 Lamia, Greece
4. Department of Informatics and Telecommunications, Postgraduate Program: ‘Information Technologies in Medicine and Biology’, University of Athens, 15784 Athens, Greece