1. Acoustic sensors;Nakamura;Trans IEE Japan,2002
2. Optical measurement of noise and vibration distribution;Nakamura;Kougaku,2000
3. For example, published Japanese translation of PCT application 2001‐508280 (P2001‐508280A): Linear power generator, application filing date 10/01/1998, or published unexamined patent application 2002‐281727 (2002‐281727A): Vibration‐based generator and light emitting device, publication date 9/27/2002.