1. Department of Electric, Electronics and Computer Engineering, University of Catania, V.le A. Doria 6, 95125 Catania, Italy
2. Department of Mathematics and Computer Science, University of Catania, V.le A. Doria 6, 95125 Catania, Italy
3. Department of Drug Sciences, University of Catania, V.le A. Doria 6, 95125 Catania, Italy