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A CASE STUDY IN ASSURANCE CASE DEVELOPMENT FOR SCIENTIFIC SOFTWAR

Assurance Cases have been effectively used for improving the safety of real-time safety systems. However, until now, Assurance Case techniques have not been applied to building confidence in the correctness of Scientific Computing (SC) software.
Our approach is to employ Assurance Case techniques to the case of a specific medical image analysis software, 3dfim+, and then generalize the results/template for other medical and SC software. Using the Goal Structuring Notation (GSN), we develop an Assurance Case to support the top goal that "Program 3dfim+ delivers correct outputs when used for its intended use/purpose in its intended environment." This claim is supported by several sub-claims, including the claims that high-quality requirements exist and that the implementation complies with the requirements. The full argument decomposes each sub-claim further until at the bottom level evidence is provided. The evidence provided includes the requirements documentation, test cases and expert review. To simplify the Assurance Case diagram, a new generic module, parameterized over quality, was developed to argue that each quality has been achieved. Evaluation of the full Assurance Case shows that this approach is feasible for building confidence in SC software, even in the practical situation where confidence is sought, but redesign and reimplementation are not possible. The exercise uncovered issues with the original documentation for 3dfim+, including missing assumptions, and ambiguity with the chosen sign convention. Furthermore, although no errors in output were found, the Assurance Case highlights that confidence in the original 3dfim+ software could be improved through additional checks for input validity. / Thesis / Master of Science (MSc)

Identiferoai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/23075
Date January 2017
CreatorsSayari Nejad, Mojdeh
ContributorsSmith, Spencer, Computing and Software
Source SetsMcMaster University
LanguageEnglish
Detected LanguageEnglish
TypeThesis

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