Building scalable hierarchical abstractions in the enriched robustness diagram with loop and time controls

The Robustness Diagram with Loop and Time Controls is a multidimensional workflow model that supports modeling of complex systems while representing all three workflow dimensions. It is built by extending the Robustness Diagrams defined by the Unified Modeling Language, where the number of robustness stereotypes and relationship types are very limited. This limitation has later on affected the Robustness Diagram with Loop and Time Control models since hierarchical abstractions, dependencies, and nesting structures cannot be represented in such models. An enrichment to the Robustness Diagram with Loop and Time Controls was conducted to partly address this problem, but there is still no representation of composition and aggregation, while the defined scalability does not include the reset-bound subsystems. Moreover, the Enriched Robustness Diagram with Loop and Time Controls was not formally defined as a whole. New arc types that explicitly represents the hierarchical abstraction structures are established in this study, where the composition structure is used to define a multilevel reset-bound subsystems. These are included in the established formal definition of the Enriched Robustness Diagram with Loop and Time Controls. Illustrations of system models comparing the upgraded enrichment to its previous model shown an improvement in terms of the model’s flexibility in modeling complex systems.