1. UNESP—São Paulo State University, School of Technology and Sciences, 19060-900 Presidente Prudente, Brazil
2. School of Electronic Engineering, Bangor University, LL57 2DG Bangor, Gwynedd, Wales, U.K.
3. UNESP—São Paulo State University, Institute of Geosciences and Exact Sciences, 13506-900 Rio Claro, Brazil