The CASCADE project focuses on the assessment and certification of safety-critical systems.
The need for system assessment is driven by the increasingly sophisticated uses to which computer-based control systems are being put (many of which would not be possible without the use of software), and the economic and technical advantages of systems incorporating such components. Because of the safety implications, there is an emerging requirement to either develop the system so that it complies with internationally recognised standards, or to purchase the system that complies with these standards. In particular, users require independent assessment of conformance that is cost-effective, objective, and which constrains liability in the event of failure. The suppliers of assessment services require that their offerings be objective (repeatable), cost effective, technically sound, generic in so far as different technical solutions chosen by implementors can be accommodated, and risk-limiting in both a technical and a legal sense.
The CASCADE project's view of system assessment is that it involves identifying a set of properties that the system must exhibit and seeking evidence supporting the existence of these properties. The technical work of how current methods, techniques, tools and management practices provide evidence to support the assessment judgement. A number of interesting technical questions will arise as the project tries to address this problem:
- How do we classify systems and determine what development and assessment methods are appropriate to these different classes of systems?
- Can we build on the assessment history of system components when we reuse them? How do we secure objective measures?
- How important are the contributions from product and process assessment?
- What constitutes an adequate audit trail for the development of safety related systems and what data should be collected to support assessment judgements?
- How can standards and technical guidelines be written so that compliance can be objectively established?
- How should we approach the development and assessment of tools which are themselves used for the development of safety related systems?
- How can formal and semi-formal methods be effectively deployed in the development of safety critical systems?
Solutions to these questions will be derived from the existing employed by the members of the project and from the results of current research being undertaken by the partners.
The project will produce a generalised framework for the assessment of systems that will be deployed by the assessors and trusted by the users. From the experience gained in the applications, the project will also produce guidelines for the development and procurement of safety critical systems, to be deployed by the users.
The results of the project will be exploited immediately both by the users and the assessors. Assessor partners will migrate the findings of the project directly into their commercial assessment work. User partners will be in a position to deploy the development guidelines in their practical development work and will be able to have their own or third party systems, assessed in accordance with the framework. Results from the project will be made available to standards organisations and the individual members of the project already represented on standards bodies will be able to make use of the work through those bodies.
CV35 0BL Warwick
GU9 7EO Farnham