Service Dependability with Continuously Revised Assurance Cases by Multiple Stakeholders: A Case Study

Recently, assurance cases have received much attentions in the field of software-based computer systems and IT services. However, software very often changes and there are no strong regulations for software. These facts are main two challenges to be addressed in software assurance cases. We propose a development method of assurance cases by means of continuous revision at every stage of the system lifecycle, including in-operation and service recovery in failure cases. The quality of dependability arguments are improved by multiple stakeholders who check with each other. This paper reported our experience of the proposed method in a case of the ASPEN education service. The case study demonstrate that the continuos updates create a significant amount of active risk communications between stakeholders. This gives us a promising perspective for the long-term improvement of service dependability with the lifecycle assurance cases.