1. Institute for Biomedical Informatics, University of Pennsylvania, 3700 Hamilton Walk, Philadelphia, PA 19104, USA
2. Department of Automatics and Robotics, AGH University of Science and Technology, al. A. Mickiewicza 30, Kraków 30-059, Poland
3. Department of Computer Science, AGH University of Science and Technology, al. A. Mickiewicza 30, Kraków 30-059, Poland