author: Bart van den Pol
title: Smarter semantics for maintainable fault trees
topics: Dependability, security and performance
committee: Enno Ruijters
end: January 2016


Fault Tree Analysis is an industry-standard tool for analyzing the reliability of systems that are critical for safety or business, such as power stations and data centers. The tool DFTCalc has been developed at the UT for the analysis of Fault Maintenance Trees, which extend the analysis by including the effects of maintenance on system reliability.

The current analysis methods suffer from a state-space explosion problem, where intermediate stages of analysis consume so much memory they cannot be analyzed. A previous bachelor project by Jip Spel has reduced this problem by identifying situations where smaller models can be used for analysis without affecting the results, but this work focused on non-maintainable FTs.

This project will search for smaller models that can be used to analyze Fault Maintenance Trees, and implement a method to automatically select the smaller models when possible.


  1. W.E. Vesely, F.F. Goldberg, N.H. Roberts, D.F. Haasl, Fault Tree Handbook, Office of Nuclear Regulatory Research, US Nuclear Regulatory Commision, 1981 (
  2. Boudali, H. and Crouzen, P. and Stoelinga, M.I.A. (2007) Dynamic Fault Tree analysis using Input/Output Interactive Markov Chains. In: Proceedings of the 37th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN), pp. 708-717. (

Additional Resources

  1. The paper