@techreport{weko_50265_1, author = "KEN-ICHIFUKUI and KAZUMI,SAITO and MASAHIRO,KIMURA and MASAYUKI,NUMAO", title = "SBSOM : Self - Organizing Map for Visualizing Structure in the Time Series of Hot Topics", year = "2004", institution = "Dept. of Information Science and Technology Osaka University, NTT Communication Science Laboratories, NTT Communication Science Laboratories, The Institute of Scientific and Industrial Research Osaka University", number = "125(2004-ICS-138)", month = "dec" }