Extending Express for Process Modeling and Monitoring

The upcoming ISO standard EXPRESS has been de-ned as a data speciication language for the use within STEP. EXPRESS supports the modeling of static structural relationships and consistency constraints whereas the applicability of EXPRESS for the modeling of behavior is very limited. Thus, at present there is an ongoing discussion by which means EXPRESS should be extended with. In this paper, we present EXPRESS-P. EXPRESS-P is an extension of EXPRESS by the concepts of the formal languages SDL (CCITT Standard), Estelle (ISO Standard), and GRAPES-86. Within these approaches a system is described as a network of communicating concurrent agents. In addition to the language, we introduce graphical means for this extension (System and Process Diagrams). Finally, we give a practical example by modeling an injection molding process in order to demonstrate the applicability of EXPRESS-P.