Department of Computer Science and Artificial Intelligence of the University of Granada, E.T.S.I.I.T., C- Periodista Daniel Saucedo Aranda s-n, 18071 Granada, Spain;Department of Computer Science and Artificial Intelligence of the University of Granada, E.T.S.I.I.T., C- Periodista Daniel Saucedo Aranda s-n, 18071 Granada, Spain;Department of Computer Science and Artificial Intelligence of the University of Granada, E.T.S.I.I.T., C- Periodista Daniel Saucedo Aranda s-n, 18071 Granada, Spain