Acknowledgments
The authors thank anonymous referees, Hiroaki Miyamoto,
Bondan Winarno, Toni Kuspuja and Ratih Madya for their comments,
advice and supports. We are also grateful to the financial
supports from the Japanese Society for the Promotion of Science as the Grant-in-Aid for Scientific Research C, Promotion Mutual Aid
Cooperation for Private Schools of Japan and Kochi University of
Technology.