Department of Informatics, University of Piemonte Orientale Amedeo Avogadro, Spalto Marengo 33, Alessandria, Italy.|Department of Informatics, University of Piemonte Orientale Amedeo Avogadro, Spalto Marengo 33, Alessandria, Italy.|Department of Informatics, University of Piemonte Orientale Amedeo Avogadro, Spalto Marengo 33, Alessandria, Italy.|Department of Informatics, University of Piemonte Orientale Amedeo Avogadro, Spalto Marengo 33, Alessandria, Italy.|Department of Informatics, University of Piemonte Orientale Amedeo Avogadro, Spalto Marengo 33, Alessandria, Italy.