Affiliation: | a Venture Business Laboratory, Hiroshima University, 2-313 Kagamiyama, Higashi Hiroshima 739-8527, Japan b Faculty of Integrated Arts and Science, Hiroshima University, 1-7-1 Kagamiyama, Higashi Hiroshima 739-8521, Japan c Oita Research Center, Sunallomer Ltd, 2 Nakanosu, Oita 870-0189, Japan |