Formal verification of uml statecharts with real-time extensions

Abstract

We present a framework for formal verification of a real time extension of UML statecharts. For clarity, we restrict ourselves to a reasonable subset of the rich UML state chart model and extend this with real-time constructs (clocks, timed guards, and invariants). We equip the obtained formalism, called hierarchical timed automata (HTA), with an operational semantics. We outline a translation of one HTA to a network of flat timed automata, that can serve as input to the real-time model checking tool UPPAAL. This translation can be used to faithfully verify deadlock-freedom, safety, and unbounded response properties of the HTA model. We report on an XML-based implementation of this translation, use the well-known pacemaker example to illustrate our technique, and report run-time data for the formal verification part.