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Zeit:  Donnerstag, 28. April 2022, 10:30 Uhr
Ort:   Raum 9222, Geb. E3, 2. Etage, Informatikzentrum, Ahornstr. 55

Der Vortrag ist auch online über Zoom zu verfolgen:
https://rwth.zoom.us/j/99709768339?pwd=MndDQ1MxMVdQWVpYZGpvYSt4bmdKdz09
Meeting-ID: 997 0976 8339, Kenncode: 975390

Referent: Matthias Volk, M.Sc.
          (Lehrstuhl Informatik 2)

Thema: Dynamic Fault Trees: Semantics, Analysis and Applications


Abstract:

Safe and reliable systems are crucial in today’s society. Fault trees are a 
prominent and widely-used model to assess and improve the reliability of 
systems. Fault trees model how component failures propagate through a system and 
lead to a failure of the overall system. Dynamic fault trees (DFTs) are an 
extension of (static) fault trees and allow more modelling flexibility by 
introducing dynamic gates, spare management, functional dependencies and failure 
restrictions.

In this presentation, we investigate dynamic fault trees in detail and consider 
three main aspects: (1) the precise semantics of DFTs, (2) the analysis of DFTs 
by model checking techniques, and (3) the application of DFTs, for example in 
the railway domain.

We first specify the semantics of dynamic fault trees in terms of generalized 
stochastic Petri nets (GSPNs). We investigate multiple semantic questions 
resulting from the combination of DFT elements. Our resulting GSPN framework 
subsumes the major existing DFT semantics and allows to pinpoint their differences.

Secondly, we present analysis techniques for DFTs based on probabilistic model 
checking. We introduce several (orthogonal) optimisation techniques which 
exploit symmetries, irrelevant failures and independent subtrees to improve the 
state-space generation times. We also show an approximation algorithm based on 
partial state-space exploration. All presented approaches are implemented in the 
open-source model checker Storm and evaluated on a DFT benchmark suite. The 
evaluation shows that our tool Storm-dft is state-of-the-art for DFT analysis.

Third, we present the application of DFTs in the railway domain. The case study 
considers train routing options in railway station areas in terms of available 
infrastructure elements. We analyse how switch failures impact the potential 
train routes in a station and determine the most critical components.


Es laden ein: die Dozentinnen und Dozenten der Informatik