Model transformation of dependability-focused requirements models

Recent research has focused on extending standard requirements elicitation processes to address potential abnormal situations that can interrupt normal system interaction at run-time. We proposed a process, DREP, that extends use case-driven modelling with elements that allow the modelling of system behaviour in exceptional situations. This paper discusses the challenge of using the notions of exceptional behaviour and outcomes defined in use cases within a MDE process. In order to create a more formal specification model with activity diagrams, the use cases have to be well-formed to begin with. We describe precise transformation rules to systematically create an activity diagram corresponding to each use case. Special stereotypes are introduced to document partial or degraded outcomes and handling activities. The model resulting from the transformation unambiguously specifies the system interactions required to satisfy the user, as well as exceptional interactions that can lead to degraded service provision.