1. Department of Electrical and Computer Engineering, University of Michigan, Ann Arbor, MI, USA
2. Department of Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, MI, USA
3. Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA
4. Department of Computational Mathematics, Science and Engineering, and the Department of Biomedical Engineering, Michigan State University, East Lansing, MI, USA