1. 1 Wroclaw University of Technology, Faculty of Microsystem Electronics and Photonics, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland, phone (fax): +48-71-3554822; e-mail: leszek.golonka@pwr.wroc.pl
2. 2Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Trojdena 4, 02-109 Warsaw, Poland