A new modeling approach to the safety evaluation of N-modular redundant computer systems in presence of imperfect maintenance

• A large number of safety-critical control systems are based on N-modular redundant architectures, using majority voters on the outputs of independent computation units. In order to assess the compliance of these architectures with international safety standards, the frequency of hazardous failures must be analyzed by developing and solving proper formal models. Furthermore, the impact of maintenance faults has to be considered, since imperfect maintenance may degrade the safety integrity level of the system. In this paper, we present both a failure model for voting architectures based on Bayesian networks and a maintenance model based on continuous time Markov chains, and we propose to combine them according to a compositional multiformalism modeling approach in order to analyze the impact of imperfect maintenance on the system safety. We also show how the proposed approach promotes the reuse and the interchange of models as well the interchange of solving tools. © 2009 Elsevier Ltd. All rights reserved.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Inbäddad systemteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Embedded Systems (hsv//eng)

Nyckelord

Bayesian Networks

Imperfect maintenance

Multiformalism modeling

N-modular redundancy

Safety

Continuous time Markov chain

Failure model

Formal model

International safety standards

Maintenance models

Majority voter

Modeling approach

Redundant architecture

Safety evaluations

Safety integrity levels

Safety-critical control systems

System safety

Distributed parameter networks

Docking

Inference engines

Intelligent networks

Interchanges

Knowledge based systems

Maintenance

Markov processes

Quality assurance

Redundancy

Regulatory compliance

Speech analysis

Standardization

Systems engineering

Software Technology

Programvaruteknik

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)