Integrating Product-Line Fault Tree Analysis into AADL Models

Fault tree analysis (FTA) is a safety-analysis technique that has been extended recently to accommodate product-line engineering. This paper describes a tool-supported approach for integrating product-line FTA with the AADL (architecture analysis and design language) models and associated AADL Error Models for a product line. The AADL plug-in we have developed provides some automatic pruning and adaptation of the fault tree for a specific product from the product-line FTA. This work supports consistent reuse of the FTA across the systems in the product line and reduces the effort of maintaining traceability between the safety analysis and the architectural models. Incorporating the product-line FTA into the AADL models also allows derivation of basic quantitative and cut set analyses for each product-line member to help identify and eliminate design weaknesses. The tool-supported capabilities enable comparisons among candidate new members to assist in design decisions regarding redundancy, safety features, and the evaluation of alternative designs. Results from a small case study illustrate the approach.