1. Philips Research USA, 345 Scarborough Road, Briarcliff Manor, NY 10510
2. Department of Mechanical Engineering, Lamar University, Beaumont, TX 77710
3. Philips-CFT, P.O. Box 218, 5600 MD Eindhoven, The Netherlands
4. Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands