Symbolic verification and analysis of discrete timed systems

This paper presents a novel approach for real-time model checking. It combines the efficiency of traditional symbolic model checking with possibilities to describe and specify real-time systems. Using multi-terminal binary decision diagrams to represent time and time intervals, it becomes possible to transfer efficient algorithms and optimization heuristics known from standard CTL model checking to real-time applications. By introducing a new variant of models called I/O-interval structures we can describe systems in a modular way. Interval structures allow model composition of real-time structures such that state explosion effects are greatly reduced. Besides model checking we also present analysis algorithms which allow to compute key properties like system latencies and minimal response times from the structures describing the system. The practical applicability is proven by experimental results, computed by the verification system RAVEN, which implements all described algorithms, including counterexample generation and waveform visualization.