Fault Trees vs. Component Fault Trees: An Empirical Study
When dealing with structural safety analysis, one of the most popular methodologies is Fault Tree Analysis (FTA). However, one major critique is the rapid increasing of the complexity, and therefore incomprehensibility, when dealing with realistic systems. One approach to overcome this are Component Fault Trees (CFT), presenting an extension to standard FT, allowing the separation of the analysis into less complex parts on the level of system components. CFTs are proposed to be more structured and partly reusable and therefore also claimed to be more straightforward to use by engineers with little safety domain experience.
In this work, we aim at getting an idea of the validity of presented theses and started an initial experiment with 13 computer science students, being asked to execute CFT or FT method on a given case study. Due to the number of participants, we focused on their empirical statements, the analysis solutions, and empirical results collected using a questionnaire.
Although the empirical impression has been that the resulting CFT models are better to use and more comprehensible than the FT models, the qualitative results have not supported this. Moreover, the component-wise modeling seams to mislead the students such that they have overseen failures outside the component structure, e. g., Common-Cause, Cross-Component, or external failures.
Parts of the work leading to this paper was funded by the Framework Programs for Research and Innovation Horizon 2020 under grant agreement n.732242 (DEIS).
- 1.Filax, M., Gonschorek, T., Ortmeier, F.: Building models we can rely on: requirements traceability for model-based verification techniques. In: Bozzano, M., Papadopoulos, Y. (eds.) IMBSA 2017. LNCS, vol. 10437, pp. 3–18. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-64119-5_1CrossRefGoogle Scholar
- 2.Höfig, K., Joanni, A., Zeller, M., Montrone, F., Rothfelder, M., Amarnath, R., Munk, P., Nordmann, A.: Model-based reliability and safety: reducing the complexity of safety analyses using component fault trees. In: RAMS (2018)Google Scholar
- 3.INCOSE: Systems Engineering Handbook: A Guide for System Life Cycle Processes and Activities. John Wiley & Sons (2015)Google Scholar
- 4.International Electrotechnical Commission (IEC): IEC 61025: Fault Tree Analysis (FTA) (1990)Google Scholar
- 5.International Electrotechnical Commission (IEC): IEC 61508: Functional safety of electrical/electronic/programmable electronic safety related systems (1998)Google Scholar
- 6.International Organization for Standardization (ISO): ISO 26262: Road vehicles - Functional safety (2011)Google Scholar
- 7.Joshi, A., Miller, S.P., Whalen, M., Heimdahl, M.P.: A proposal for model-based safety analysis. In: 24th DASC (2005)Google Scholar
- 8.Jung, J., Jedlitschka, A., Höfig, K., Domis, D., Hiller, M.: A controlled experiment on component fault trees. In: Bitsch, F., Guiochet, J., Kaâniche, M. (eds.) SAFECOMP 2013. LNCS, vol. 8153, pp. 285–292. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-40793-2_26CrossRefGoogle Scholar
- 9.Kaiser, B., Liggesmeyer, P., Mäckel, O.: A new component concept for fault trees. In: Proceedings of the 8th Australian Workshop on Safety Critical Systems and Software (2003)Google Scholar
- 10.Lisagor, O., McDermid, J., Pumfrey, D.: Towards a practicable process for automated safety analysis. In: ISSC 24 (2006)Google Scholar
- 11.McDermid, J., Kelly, T.: Software in safety critical systems: achievement and prediction. University of York, UK (2006)Google Scholar
- 14.Vesely, W.E., Goldberg, F.F., Roberts, N.H., Haasl, D.F.: Fault Tree Handbook. US Nuclear Regulatory Commission (1981)Google Scholar
- 15.Yin, R.K.: Case Study Research and Applications: Design and Methods. Sage Publications, Thousand Oaks (2009)Google Scholar