Markus Baumeister

Abstract of "An object model for representation and re-use of chemical engineering process models" (dt.: Ein Objektmodell zur Repräsentation und Wiederverwendung verfahrenstechnischer Prozeßmodelle)

Development of new chemical processes and improvement of old ones is one task of chemical engineering. This is often supported by modeling these processes in mathematical terms. Due to the required abstraction from the complexity of the real world building such mathematical models is a design process in itself. To improve speed and quality of the modeling final and intermediate results of the design process should be re-used if possible. But re-use causes the well-known problems of finding and adapting model parts. The latter is worsened in chemical process engineering since the actual plants to be modeled are already one of a kind. Known solutions - neither from within chemical engineering nor from outside - can't solve both finding and adapting easily at the same time.

This work therefore inspects possible object models and operations on them to develop - based on the modeling language VeDa - an object model for storing and re-using chemical process models. It can be shown that the two problems of re-use - finding and adapting - fall together with the class-based and the prototype-based object oriented paradigm and that its is not possible to simply merge these paradigms to get the best of both worlds. But a merge of their features can be achieved by emulating prototype-based behaviour on top of a class-based object model. The number of intersection classes, which would normally rise sharply, can be limited by introducing a mechanism for multiple instantiation called 'Aspects'. To handle meta classes coherently in the same scheme a method is proposed which can replicate all required functions of the meta levels in a two-layered object model.