Panagiotis (Pete) Manolios
Khoury College of Computer and Information Sciences
Northeastern University

A Model-Based Framework for Analyzing the Safety of System Architectures

Panagiotis Manolios, Kit Siu, Michael Noorman and Hongwei Liao.
RAMS, 2019 © IEEE


We introduce a compositional, model-based framework for modeling, visualizing and analyzing the safety of system architectures for safety-critical cyber-physical systems. Our work provides a unified, end-to-end, framework that encompasses high-level models, fault trees and qualitative and quantitative safety analyses in one semantically coherent framework. Our framework enables the rapid development, modification and evaluation of architectures for complex systems.

Our framework includes a modeling language for defining libraries of component models that include information on component reliability, connectivity and fault propagation. System architectures consist of a sequence of component instantiations, component connections, and the identification of top-level faults. Our framework includes algorithms for automatically synthesizing and reducing fault trees from architectures and library models. The generated fault trees are then automatically analyzed to determine cutsets and the probability of top-level faults. Finally, our framework includes visualization algorithms that depict fault trees and architectures at various levels of abstraction. We provide a case study of a model inspired by the Boeing 777 IMA architecture.

The framework is compositional because safety engineers only need to define reliability and fault propagation aspects at the component level. This is in contrast with current methods used in the field of avionics, where safety engineers directly construct system-level fault trees. Defining such fault trees requires significant expertise, time and care. Small changes to architectures can result in significant changes to fault trees. All of this makes analyzing a collection of architectures error- prone and prohibitive both in terms of time and money. We developed an open source tool that implements our framework, and provide an experimental evaluation consisting of the modeling and analysis of a collection of architectures. Our model-based framework provides a new paradigm, allowing significant automation in the area of safety analysis of architectures for complex avionics systems.
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