SGSN: Tool Support for GSN Development

Graphical argument structures such as Goal Structuring Notation (GSN) are increasingly being used in practice as a means to provide safety assurance to stakeholders, such as regulatory authorities, regarding the dependability and safety of a system. These argument-based assurance cases are utilized in practice to demonstrate that a system is suitable for its intended use. In this paper, we present Structured GSN (SGSN), an open-source tool to create and edit assurance cases. In addition to basic functionalities related to the creation of GSN, we added two types of analysis, syntactic analysis which checks if the developed GSN satisfies structured criteria, and semantic analysis which checks compartmental properties. For the semantic analysis, we mapped the GSN to a formal model i.e., Markov Decision Process (MDP), and checked properties expressed in PCTL using a probabilistic model-checker.