Model Refactorings as Rule-Based Update Transformations Ivan Porres TUCS Turku Center for Computer Science Åbo Akademi University Lemminkäinsenkatu 14A, FIN-20520 Turku, Finland e-mail:ivan.porres@abo.fi Turku Centre for Computer Science TUCS Technical Report No 525 April 2003 ISBN 952-12-1163-6 ISSN 1239-1891