Abstract: A model based on extended UML sequence diagram was given, for modeling operational event trace descrip- lion, which is one of the productions of Dol)八F. The model includes graphics and formal description. The lifeline of se- qucnce diagram was defined as time message, and the homologous relationship between sequence diagram and petrinets was studied, and then the arithmetic of sectuence diagram mapping to petrinets was given. After that, the arithmetic of extended sequence diagram mapping to object-based petrinets was studied. And the self-message was considered as spe- cial. At last, an example was given based on the air defense process.

Key words: Object-based petrinets,Operational event trace description,Validation and evaluation