  We propose here a framework to model real-time components consisting of
concurrent real-time tasks running on a single processor, using parametric
timed automata. Our framework is generic and modular, so as to be easily
adapted to different schedulers and more complex task models. We first perform
a parametric schedulability analysis of the components using the inverse
method. We show that the method unfortunately does not provide satisfactory
results when the task periods are consid- ered as parameters. After identifying
and explaining the problem, we present a solution adapting the model by making
use of the worst-case scenario in schedulability analysis. We show that the
analysis with the inverse method always converges on the modified model when
the system load is strictly less than 100%. Finally, we show how to use our
parametric analysis for the generation of timed interfaces in compositional
system design.
