Takayuki Itoh Hiroki Takakura Atsushi Sawada Koji Koyamada Hierarchical Visualization of Network Intrusion Detection Data. 40-47 2006 26 IEEE Computer Graphics and Applications 2 http://doi.ieeecomputersociety.org/10.1109/MCG.2006.34 db/journals/cga/cga26.html#ItohTSK06