Synthesis and stochastic assessment of schedules for lacquer production

The Modest modeling language pairs modeling features from stochastic process algebra and from timed and probabilistic automata with light-weight notations such as exception handling. It is supported by the Motor tool, which facilitates the execution and evaluation of Modest specifications by means of the discrete event simulation engine of the Mobius tool. This paper describes the application of Modest, Motor and Mobius to a highly nontrivial case. We investigate the effect of faulty behavior on a hard real-time scheduling problem from the domain of lacquer production. The scheduling problem is first solved using the timed model-checker Uppaal. The resulting schedules are then embedded in a Modest failure model of the lacquer production line, and analyzed with the discrete event simulator of Mobius. This approach allows one to assess the quality of the schedules with respect to timeliness, utilization of resources, and sensitivity to different assumptions about the reliability of the production line.