Affiliation: | Department of Computer Science, Katholieke Universiteit Leuven Celestijnenlaan 200A, B-3001 Heverlee, Belgium E-mail: Luc.DeRaedt{at}cs.kuleuven.ac.be Department of Intelligent Systems, Joef Stefan Institute Jamova 39, 1001 Ljubljana, Slovenia E-mail: Nada.Lavrac{at}ijs.si |