1. Department of Computer Science and Engineering, University of Bologna, Cesena, Italy
2. Department of Sciences and Methods of Engineering, University of Modena and Reggio Emilia, Urbino, Italy
3. Department of Pure and Applied Sciences, University of Urbino Carlo Bo, Reggio Emilia, Itay
4. Department of Sciences and Methods of Engineering, University of Modena and Reggio Emilia, Reggio Emilia, Itay