Combining Various Solution Techniques for Dynamic Fault Tree Analysis of Computer Systems
HASE '98 The 3rd IEEE International Symposium on High-Assurance Systems Engineering
The Galileo Fault Tree Analysis Tool
FTCS '99 Proceedings of the Twenty-Ninth Annual International Symposium on Fault-Tolerant Computing
Dynamic Fault Tree Analysis Using Input/Output Interactive Markov Chains
DSN '07 Proceedings of the 37th Annual IEEE/IFIP International Conference on Dependable Systems and Networks
Simulation and the Monte Carlo Method (Wiley Series in Probability and Statistics)
Simulation and the Monte Carlo Method (Wiley Series in Probability and Statistics)
A compositional semantics for dynamic fault trees in terms of interactive Markov chains
ATVA'07 Proceedings of the 5th international conference on Automated technology for verification and analysis
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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.