M. Trapp, B. Schürmann, T. Tetteroo
Analyzing the Behavior of Embedded Systems concerning Graceful Degradation
To be published in: Journal "Parallel and Distributed Computing Practices". Nova Science Books and Journals . Hauppauge, NY (USA), 2002 ,
Abstract
Reliability is a crucial aspect of embedded systems. Achieving reliable systems
is based on fault-tolerance covering hardware failures and an adequate design pr
ocess that minimizes development faults. E.g., model checking may be used to ver
ify small and medium sized systems.
However, we are interested in designing large distributed embedded systems with
weak safety requirements like building automation systems or automotive comfort
systems. Such systems confront hardware failures by graceful degradation instead
of using redundant stand-by systems. Nevertheless, during system development we
also need to analyze the failure behavior of our systems to achieve predictable
gradations of their functionality.
Today, the analysis will usually be done by standard methods like FTA and FMEA c
onsidering the existence of faults, only. Gradations of errors, as we are intere
sted in, are not regarded. We therefore developed an advanced failure behavior a
nalysis method which yields more sophisticated and graded results. We obtain com
prehensive results by assigning a quality description to all the information in
a system and extending the pure information flow to an information quality flow,
that models system failure behavior, too. This article gives a detailed overvie
w of that analysis method.
