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).

The recent demand in Europe and the United States for a higher level of safety in the development and operations of systems is so much so that one has come to think of it as obligatory to report system safety related cases.At D-Case we base our research and development on these reported safety cases.A safety case is a document that discusses the safety of a system based on the test results and validation results and is used as a gurantee or as an assuarance for users and system certifiers.In recent years D-Case is used not only for safety issues but also for security and dependability as well.These cases are known as security cases and dependability cases respectively.Using a more generalized term the above mentioned cases are also known as assuarance cases. In order to achieve the dependability of open systems, the concept of evidence based discussion and guarantee is deemed important.And thus Dcase was born to develop safety cases in accordance with the open system dependability concept.

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.

 In addition to the basic research and development up to now, the D-Case team is in full swing to popularize D-Case among a vast majority of Japanese company personnel.