Software Engineering Institute

Components in an AADL (Architecture Analysis and Design Language) model can have modes that determine which subcomponents and connections are active. Transitions between modes are triggered by events originating from the modeled system’s environment or other components in the model. Modes and transitions can occur on any level of the component hierarchy. The combinations of component modes (called system operation modes or SOMs) define the system’s configurations. It is important to know which SOMs can actually occur in the system, especially in the area of system safety, because a system may contain components that should not be active simultaneously, for example, a car’s brake and accelerator. This report presents an algorithm that constructs the set of reachable SOMs for a given AADL model and the transitions between them.