What is D-Case
1. D-Case 'Outline'
DCase is a tool and technique intended for people involved with a system (stakeholders) to
mutually comprehend the “dependability of a system” and to inform the public about the
aforementioned dependability in a responsible manner.Furthermore research is being conducted
to achieve open systems dependability with DScript in the
DEOS process(Fig.1).

Although safety cases are currently used for communication between system suppliers, third party consultants and system users (Ministry of Defence etc.) it is primarily used as a document that is submitted for certification.In addition to basic research through experiments and discussion with companies in the DEOS so far, the following three points are important for practical use.
1. The development of training and easy-to-understand introductory book
Safety cases until now has been put together by consultants with advanced expertise in
systems of high level safety requirements.Therefore safety case guidebooks were assumed
to include only advanced expertise such as safety analysis.For open systems dependability to
achieve its goal, it is essential that a large number of company personnel participate in the
process.In order to get a large number of company personnel to participate, it is necessary
to have an easy-to-understand introductory book and training.
2. Development of user-friendly tools that meet the necessary requirements
Since safety cases started spreading, there were only a few available tools such
as the ASCE from Adelard UK.But the ASCE is a tool that is mainly used for creating
certification documents.Hence a better tool tailored for the actual needs of companies was required.
3. Increase in publically available examples
One of the problems of safety cases is that actual examples are not available
because they contain important information regarding the companies.Therefore it is difficult for company personnel (specially Japanese company personnel) to grasp the concept of safety case.Hence easy-to-understand description examples and application examples has
become a necessary requirement.