1. Department of Civil Engineering and Architecture, University of the Ryukyus , 1 Senbaru, Nishihara, Okinawa, Japan
2. Prometech Software, Inc. , 7-3-1 Hongo, Bunkyo-ku Tokyo, Japan
3. Department of Systems Innovation, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku Tokyo, Japan