MIRA KAJKO-MATTSSON1, RAMIN KARIM2, and ANITA MIRJAMDOTTER3
1 School of Information and Communication Technology, KTH Royal Institute of Technology, Sweden 2 Division of Operation and Maintenance Engineering, Lule? University of Technology, SE-971 87 Lule?, Sweden 3 Informatics, School of Computer Science, Physics and Mathematics, Linnaeus University, V?xj?/Kalmar, Sweden