1. Information and Telecommunication Technology Center, Department of Electrical Engineering and Computer Science, The University of Kansas, Lawrence, Kansas
2. Information and Telecommunication Technology Center, Department of Electrical Engineering and Computer Science, The University of Kansas, Lawrence, Kansas and School of Computing and Communications (SCC) and InfoLab21, Lancaster University, UK and The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong