1. Department of Informatics, University of Minho, Campus of Gualtar, Braga, Portugal
2. Department of Physics, University of Minho, Campus of Gualtar, Braga, Portugal
3. High-Assurance Software Laboratory, INESC TEC, Department of Informatics, University of Minho, Campus of Gualtar, Braga, Portugal
4. International Iberian Nanotechnology Laboratory, Braga, Portugal
5. Centro de Física, Universidade do Minho, Campus de Gualtar, Braga, Portugal