Formal analysis of fault tree using probabilistic model checking: A solar array case study

Abstract

Fault Tree Analysis (FTA) is a widespread technique used to assess the reliability of safety-critical systems. The traditional way of conducting FTA is either through paper and pencil proof or through computer simulation techniques, which are inefficient and prone to inaccuracy. In this paper, we propose the use of probabilistic model checking to automatically analyze fault trees of safety-critical systems. Our methodology consists in the probabilistic formalization of the gates used in a fault tree to a Discrete-Time Markov Chain (DTMC) and a Markov Decision Process (MDP), and the subsequent probabilistic verification using PRISM tool to quantitatively analyze the system. To illustrate the proposed approach we perform the fault tree analysis of a solar array system, used as power source for the DFH-3 satellite. The results show that harsh thermal environment is the main cause of system failures.

Maintenance of Smart Buildings using Fault Trees

“…However, these techniques neglect reliability measurements and focus only on synthesis of maintenance policies in the presence of degradation and faults. The current industrial standard for measuring a system's reliability is the use of Fault trees, where the focus is on nding the root causes of a system failure using a top-down approach and do not incorporate degradation of system components and maintenance action [1,20,23]. [22] presents the Fault Maintenance Tree (FMT) as a framework that allows to perform planning strategies for balancing total costs and reliability and availability of the system.…”

“…The choice on the type of maintenance depends on several factors, including the di erent costs of maintenance and failures, and the practical feasibility of performing maintenance. To this end, we aim to address the following maintenance questions: (1) what is the optimal maintenance strategy that minimises system failures? ; (2) what is the best trade-o between cost of inspections, operation and maintenance, vs the system's number of expected failures?…”