I gratefully acknowledge Professors Emeritus T. Nakamura, M. Baba and Professor Y. Sakemi for helpful discussions and support for the database on nuclear reactions and high-energy neutron experiments at CYRIC, Tohoku University. We also acknowledge Dr Alexander Prokofiev for cordial support in high-energy neutron experiments at TSL, Uppsala University. Communicative discussions with Drs. C. Slayman, S.-J. Wen of Cisco Systems Inc., N. Seifert of Intel, R. Baumann of TI, M. Nicolaidis of TIMA Laboratory, D. Alexandrescu and A. Evans of iRoc, T. Uemura of Fujitsu Laboratory and H. Kobayashi of SONY are deeply acknowledged. I am also grateful to Professors K. Kobayashi of Kyoto Institute of Technology, H. Onodera of Kyoto University, Drs. M. Yoshimura and Y. Matsunaga of Kyushu University for giving valuable information on SEU tolerant flip-flops and EDA tools. Invaluable discussions and information are given by Drs. Kuboyama, and D. Kobayashi of JAXA, Professor Y. Takahashi of Nippon University, and Ms. A. Makihara of HIREC.