Specialist Areas
QUARC
The QUARC project (QUAntification of Reliability in Computer-based systems) is undertaken under contract to British Energy plc, and is part
of the Nuclear Safety Research Programme on C&I funded by the UK nuclear industry. The first project undetaken in 1995 was on reliability
quantification without dynamic testing (QUARC1), but subequent QUARC projects have extended the research to include information from program
structure, testing and the development process. QUARC 5 applied these reliability quantification concepts to industrial examples.
The main achievements of the QUARC project are:
- A methodology for the development and maintenance of a safety case. Many of the concepts have been included (under licence) in
our ASCAD - Adelard Safety Case Development Manual
- A theoretical study of the factors affecting reliability growth, which led to the development of a worst case bound model for placing
conservative bounds on software reliability on the basis of prior estimates of fault density and operating time (ISSRE 96 and IEEE Trans. Rel)
- Design methods to support a safety case (notably formal methods and fail-safe software implementation techniques. One novel concept was the use of reversible
computing to enhance fail-safety (ISSRE 97)
- Extension of the worst case bound theory to demand based systems and less pessimistic bounds (ISSRE 2002)
- Methods for estimating residual faults (Safecomp 2002, DSN 2002)
- A method for rescale a reliability bound for a new operational profile and a theory of "fair testing" that results in programs that are insensitive to change in
operational profile (ISSTA 2002)
- Application of residual fault, reliability bound estimation and fair testing theory to typical industrial logic (unpublished)