Masayuki Matsumoto Tadao Tsurumaki Satoru Kitamura Dai Watanabe Kinji Mori Assurance Evaluation Technology of Train Control System for Achieving Expansion during Operation . 71-78 2002 conf/hase/2002 HASE http://csdl.computer.org/comp/proceedings/hase/2002/1769/00/17690071abs.htm db/conf/hase/hase2002.html#MatsumotoTKWM02