KERMIT, Research Unit Knowledge-based Systems, Ghent University, Coupure links 653, Ghent, Belgium. Bram.Slabbinck@UGent.be|KERMIT, Research Unit Knowledge-based Systems, Ghent University, Coupure links 653, Ghent, Belgium. Bram.Slabbinck@UGent.be|KERMIT, Research Unit Knowledge-based Systems, Ghent University, Coupure links 653, Ghent, Belgium. Bram.Slabbinck@UGent.be|KERMIT, Research Unit Knowledge-based Systems, Ghent University, Coupure links 653, Ghent, Belgium. Bram.Slabbinck@UGent.be|KERMIT, Research Unit Knowledge-based Systems, Ghent University, Coupure links 653, Ghent, Belgium. Bram.Slabbinck@UGent.be