Department of Informatics, University of Bergen, HIB, N5020 Bergen, Norway. trondb@ii.uib.no|Department of Informatics, University of Bergen, HIB, N5020 Bergen, Norway. trondb@ii.uib.no|Department of Informatics, University of Bergen, HIB, N5020 Bergen, Norway. trondb@ii.uib.no|Department of Informatics, University of Bergen, HIB, N5020 Bergen, Norway. trondb@ii.uib.no