1. Tsuchiura Research Laboratory, Research & Development Group, Hitachi Plant Technologies, Ltd., 603 Kandatsu–machi, Tsuchiura–shi, Ibaraki–ken 300–0013, Japan
2. Department of Mechanical Engineering, National Defense Academy, 1–10–20 Hashirimizu, Yokosuka–shi, Kanagawa–ken 239–8686, Japan
3. Development Department, Shinkawa Sensor Technology, Inc., 4–22 Yoshikawa Kogyodanchi, Higashihiroshima–shi, Hiroshima–ken 739–0153, Japan
4. Tsuchiura Works, Hitachi Plant Technologies, Ltd., 603 Kandatsu–machi, Tsuchiura–shi, Ibaraki–ken 300–0013, Japan