1. Faculty of Economics, Shiga University, Hikone, Shiga 522, Japan
2. Department of Physics, Nagoya University, Nagoya 464-01, Japan
3. Chubu Polytechnic Center, Komaki, Aichi 485, Japan
4. Faculty of General Education, Aichi University, Toyohashi, Aichi 441, Japan
5. Faculty of Political Science and Economics, Matsusaka University, Matsusaka, Mie 515, Japan