Probabilistic Model-Based Safety Analysis

TL;DR

This paper demonstrates how probabilistic model-based safety analysis using functional models with synchronous semantics can provide precise, early-stage safety assessments of complex systems, overcoming computational limitations of previous methods.

Contribution

It introduces a method to reuse functional models for quantitative safety analysis with probabilistic failure modeling, enhancing early design safety assessment.

Findings

Effective probabilistic failure modeling demonstrated

Reusability of functional models for safety analysis shown

Improved accuracy in early safety assessment achieved

Abstract

Model-based safety analysis approaches aim at finding critical failure combinations by analysis of models of the whole system (i.e. software, hardware, failure modes and environment). The advantage of these methods compared to traditional approaches is that the analysis of the whole system gives more precise results. Only few model-based approaches have been applied to answer quantitative questions in safety analysis, often limited to analysis of specific failure propagation models, limited types of failure modes or without system dynamics and behavior, as direct quantitative analysis is uses large amounts of computing resources. New achievements in the domain of (probabilistic) model-checking now allow for overcoming this problem. This paper shows how functional models based on synchronous parallel semantics, which can be used for system design, implementation and qualitative safety analysis, can be directly re-used for (model-based) quantitative safety analysis. Accurate modeling of different types of probabilistic failure occurrence is shown as well as accurate interpretation of the results of the analysis. This allows for reliable and expressive assessment of the safety of a system in early design stages.