Enhancing Metamodels with Scenarios: Plug-&-Simulate Extensions for Model Developers

In a previous work, we presented the concept of metamodels, an extension to system dynamics that allows the development and specialization of domain models. A domain model provides a high-level representation for the elements that compose a knowledge area. Specific models developed for the domain are based on these elements, inheriting their behavior from the domain model. Traditional system dynamics constructors (stocks, rates, and processes) describe the behavior of domain elements. Domain models are believed to simplify model development within a knowledge area. In this paper, we present scenario models, which act as “plug-&-simulate” extensions to domain models. A scenario model allows a developer to change the behavior of domain elements without direct and error-prone intervention in the domain model equations. While analyzing a model, a developer can select relevant scenarios and activate them upon the model components. The model behavior is adjusted for the selected scenarios, presenting their impact upon the original model behavior. We present the system dynamics metamodel, the structure of scenario models, and their integration with specific models.