1. Ph.D. Student, Dept. of Civil Engineering, Univ. of Coimbra, Pólo II, Coimbra 3030-788, Portugal (corresponding author).
2. Professor, Dept. of Civil Engineering, Univ. of Minho, Braga 4800-058, Portugal.
3. Professor, Dept. of Civil Engineering, Univ. of Coimbra, Pólo II, Coimbra 3030-788, Portugal.
4. Professor, Dept. of Informatics Engineering, Univ. of Coimbra, Pólo II, Coimbra 3030-788, Portugal.
5. Professor, Dept. of Computer Science, Katholieke Universiteit Leuven, Celestijnenlaan 200a, P.O. Box 2402, Leuven 3001, Belgium.