We present DFTSim, a simulation tool for dynamic fault trees (DFT). The simulation is carried out by directly sampling the failure distributions attached to the leaves (called basic events) of the tree and propagating the failure times upwards in the tree. Sampling the distributions of the DFT leaves is however not obvious. To sample from the correct distributions, the analytical expression of the failure distributions of all basic events (BE) must be known. These are indeed known for non-spare BEs; but for spare BEs, they become conditional on the failure of other BEs. Hence, the derivation of the analytical expression of the spares’ failure distributions and their sampling is not a trivial task. We evaluate DFTSim by applying it on an extensive benchmark comprised of seven case studies. We compare its results to two other DFT-based reliability tools (namely Galileo and Coral) that, rather than giving simulation-based estimates, compute exact measures. Our simulation-based approach is, in particular for large DFTs, much faster than the existing approaches. In fact, the computation time of the exact solution methods is exponential in the number of DFT leaves, whereas simulation time is linear in the number of leaves. Moreover, DFTSim (and simulation in general) allows to simulate a wide range of distributions and evaluate Markovian as well as non-Markovian models.
|Title of host publication||Proceedings of the 42nd Annual Simulation Symposium (ANSS 2009)|
|Editors||G.A. Wainer, C.A. Shaffer, R.M. McGraw, M.J. Chinni|
|Place of Publication||San Diego|
|Publisher||Association for Computing Machinery (ACM)|
|Number of pages||8|
|Publication status||Published - Mar 2009|
|Publisher||Society for Modeling and Simulation International|
- Dynamic Fault Trees
- EC Grant Agreement nr.: IST-004527
- EC Grant Agreement nr.: FP7-ICT-2007-1
- reliability benchmark
- dependability analysis
- EC Grant Agreement nr.: FP7/214755
Boudali, H., Nijmeijer, A., Nijmeijer, A. P., & Stoelinga, M. I. A. (2009). DFTSim: A Simulation Tool for Extended Dynamic Fault Trees. In G. A. Wainer, C. A. Shaffer, R. M. McGraw, & M. J. Chinni (Eds.), Proceedings of the 42nd Annual Simulation Symposium (ANSS 2009) (pp. 31). San Diego: Association for Computing Machinery (ACM).