Yuichi Hattori Sozo Inoue Go Hirakawa Visualization for Activity Information Sharing System Using Self-Organizing Map. 537-542 2011 BWCCA http://doi.ieeecomputersociety.org/10.1109/BWCCA.2011.87 conf/bwcca/2011 db/conf/bwcca/bwcca2011.html#HattoriIH11