Advanced hierarchical event-stream model and the real-time calculus

Abstract

Analyzing future distributed real-time systems, automotive and avionic systems requires compositional real-time analysis techniques. Well known established techniques as Sympta/S and the real-time calculus are candidates for solving the mentioned problem. However, both techniques use quite simple event models. Sympta/S is based on discrete events, the real-time calculus on continuous functions. Such simple models have been chosen because of the computational complexity of the considered mathematical operations required for real-time analysis. Advances in approximation techniques are allowing the consideration of more expressive descriptions of events. In this paper such a new expressive event model and its analysis algorithm are described. It integrates the models of both techniques. This also allows to propagate the approximation through the analysis of a distributed system leading to a much more efficient analysis. We will also show the integration of the hierachical event-stream model and therefore the event driven real-time analysis, the periodic, and the sporadic task model with the real-time calculus. For the event-driven real-time analysis, flexible approximative analysis approaches are proposed to allow an efficient real-time analysis. We will provide an easy but powerful approximative description model for the real-time calculus. In contrary to the existing description model the degree of approximation is choosable allowing a more accurate description.