I dedicate this work to my son Simone, to my father Luigi, that always helps me from the heaven, to Silvia, the person I love and with whom I divided a beautiful life.


Thanks to my mother Giuliana who helps me and believes me, to my brothers and their sons: Umberto, Elena and Marco.


Special thanks to my friend Carla with whom I've worked with Quality Center. You have teached me to be accurate and be attention to the particular things. The period we worked together is one the best in my career.


Thanks to all my collegues, in special manner to Marilena(the chief), Massimo and Danilo, my collaborators.


Thanks also to all the others collegues in particular: Nino, Paolo, Biagio, Antonio, Angela, Danilo, Stefano, Samuele, Alessandro ed Elisabetta.


Thanks to my actual collegues, Leo and Angelo  that I respect and appreciate a lot and I feel very near.


Thank to all QC Forum Friends: Jan, John, Vladimir, Hanuman, Chris, Yordis and others HP R&D friends from Israel Koby, Jenny, Roy, Albert.


Thanks to Luca M. (txt), Diego and Francesco from whom I learn the good programming.


Thanks to all my friends, in particular manner: Paola, Flavio, Lale, Ricky, Andrea M., Andrea "Garpez" DB, Chicco, Zeta e Pimmy.