RATAD, Reliability And Timing Analysis of Distributed systems
Project no: 0005-19
Hans Hansson and Christer Norström
Mälardalen University, Computer Engineering Department, MRTC
Application, support letter 1 from ABB Automation Products AB and support letter 2 from Datex-Ohmeda
Comments by evaluators.
Support: 1 PhD student for 2 years decided 00-06-16.
Start: 2000-11-01 with Thomas Nolte as PhD student.
Reports: First-year-report

Industry contact

Mårten Larsson
Datex-Ohmeda AB
Project 1: TATOO Test And Testability Of Distributed Real-time Systems
Project 2: RATAD, Reliability And Timing Analysis of Distributed systems
Krister Hagman,
ABB Automation Products AB
Project: RATAD, Reliability And Timing Analysis of Distributed systems


Modelling and analysis are important tools in the development of safety critical real-time systems. The introduction of state-of-the-art analysis techniques in industry is however rather slow. One reason for this is the pessimism in models and analysis, e.g., schedulability analysis for realistic systems are typically based on simplifying assumptions which leads to pessimism that forces designers to make costly overdesigns, dimensioning the system for worst-case situations that may never occur. At the same time, the over all system requirement is to satisfy a reliability measure of, say, at most 10-9 faults per hour.

This project proposes a reliability analysis method that considers the effects of faults and timing parameter distributions (including execution time distributions, jitter distributions, and sporadic task inter-arrival time distributions) on schedulability analysis. The goal is to provide designers with well founded support that allow them to make trade-offs between timing guarantees and reliability, i.e. by allowing occasional deadline misses a less costly implementation may be used, while still satisfying the over all reliability requirement.




  1. Nolte, T., Reducing Pessimism and Increasing Flexibility in the Controller Area Network. Licenciate thesis, Mälardalen University May 12, 2003.
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