A layered metamodel for hierarchical modeling in UML

As software is becoming larger and more complex, it is increasingly important to use the hierarchical modeling approach. Unfortunately, however, UML does not specify each metamodel with hierarchy for model by modeling phase. Thus, most UML-baaed methodologies do not address the hierarchical modeling for model. As a method for supporting hierarchical modeling on UML, this paper proposes a layered metamodel which defines hierarchically modeling elements of model according to the modeling phase. We describe each metamodel with hierarchy for models in UML, then present the hierarchical integrated metamodel combined with each metamodel by three modeling phases (conceptual phase, specific phase, and concrete phase). Therefore, designers are able to construct the hierarchical model by applying the metamodel with hierarchy. Using the hierarchical metamodel enables designers to improve the usability of UML and reusability of application model.