- 2000 - -早稲田大学大学院国際情報通信学科(GITS)教授・委員長
- 2000 - -Professor , Graduate School of Global Information and Telecommunication Studies GITS,
- 1998 - - 早稲田大学国際情報通信研究センター(GITI)所長
- 1998 - -Director,Global Information and Telecommunication Institute,
- 1990 - 1996 郵政省郵政研究所研究官
- 1990 - 1996 Institute for Posts and Telecommunications Policy,
- 1978 - 1979 英国エセックス大学訪問教授
- 1978 - 1979 University of Essex, Visiting Professor
- 1976 - 1978 東北大学電気通信研究所流動研究員
- 1976 - 1978 Study Groups on Electrical Communication,
- 1971 - 1976 Waseda University School of Science and Engineering
- 1971 - 1976 Waseda University, Associate Professor
- 1976 - - 早稲田大学理工学部教授
- 1976 - - Waseda University, Professor
- 1964 - 1971 日本電信電話公社勤務
- 1964 - 1971 Nippon Telegraph and Telephone corporation
- Waseda University,
- Researcher
- Tohoku University, Researcher
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