Towards Argumentation Schemes for Open Systems Dependability

A communication gap between developers and operators can lead to serious problems on system service continuity, especially for open systems with constant changes of stakeholders´ requirements and operating environment. In order to break down such communication barriers, this paper gives general patterns of reasoning, called argumentation schemes, for open system dependability. The schemes are defined in terms of system lifecycle taking into account an iterative developing and operating processes for service continuity. They are used to embody assurance cases written in a form of the goal structuring notation. A collaborative experiment with a software developer shows that the schemes promote communication between developers and operators in such a way that dependable operating measures considered in development phases improve the next operation and dependable developing measures obtained in operation phases improve the next development. Moreover, the schemes contribute to find flaws of development processes taken by the software developer.