Iñigo Perona Ibai Gurrutxaga Olatz Arbelaitz José Ignacio Martín Javier Muguerza Jesús M. Pérez Service-independent payload analysis to improve intrusion detection in network traffic. 171-178 2008 AusDM http://crpit.com/abstracts/CRPITV87Perona.html conf/ausdm/2008 db/conf/ausdm/ausdm2008.html#PeronaGAMMP08