Parameterised Argument Structure for GSN Patterns

GSN (Goal Structuring Notation) is a graphical notation widely used to construct assurance cases, which are required for the system assurance of safety critical systems. Patterns and their supporting constructs are proposed in GSN, which include parameterized expressions in order to facilitate the reuse of existing assurance cases. Unfortunately the current GSN does not provide the precise account of parameterized expressions, thereby it is hard to automate their consistency check. The aim of this paper is to present a new proposal towards parameterisation of patterns in GSN and to show its formal background. We will present a new parameterised expressions with types, their scoping rules and type checking mechanism, which provide the safeguard to misuses of parameterised patterns and the means to automate checking their type consistency.