Quiescence in Timed Automata

title:Quiescence in Timed Automata
contact:M. Gerhold MSc & dr. M.I.A. Stoelinga
to be started:any time


Quiescence, or the absence of outputs is  an important notion in model-based testing. A system-under-test (SUT) must fail a certain test case if an output is required, but the SUT does not provide one. Therefore, absence of outputs if often labeled via a special quiescence label, delta.

In practice, it is difficult (and even impossible) to determine if a required output will never be given. Therefore, it is implemented by a time out: if no output occurs after M seconds, then it is assumed that no output will occur anymore.

Therefore, it makes sense to investigate the notion of quiescence by means of timed automata: suppose that we model everything (ie the SUT and the requirements) by means of timed automata, do we then get the same results as before, with the delta-labeling approach?


- study the concept of quiescence

- study timed automata, and the tool Uppaal (see www.uppaal.org)

- transform delta-labeled automata into timed automata

- compare the results