1. Department of Computer Science, Universidad Industrial de Santander, Bucaramanga, Colombia
2. Department of Electronics Engineering, Universidad Industrial de Santander, Bucaramanga, Colombia
3. Department of Computer Science and Engineering, Washington University in St. Louis, St. Louis, MO, USA
4. Department of Electrical and System Engineering and the Department of Computer Science and Engineering, Washington University in St. Louis, St. Louis, MO, USA
5. Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA