The growing popularity of sequence charts, first of all Message Sequence Charts and UML Sequence Diagrams, for the description of communication behavior has evoked criticism regarding the semantics of the charts which led to extensions of these standardized visual formalisms. One such extension are Live Sequence Charts which allow to distinguish mandatory and possible behavior in protocol specifications. In the original language definition for LSCs the semantics are only described informally, although a sketch for a possible formalization has been provided as well. In this paper we intend to fill in the semantic blanks of the original LSC definition. Following the sketched path we define the semantics of an LSC by deriving a Timed Büchi Automata from it. We also consider qualitative and quantative timing aspects. We finally show how LSCs are integrated into a verification tool set for Statemate designs.

Live Sequence Charts (LSCs) are an established visual formalism for requirements in formal, model-based development, in particular aiming at formal verification of the model. The model-checking problem for LSCs is principally long solved as each LSC has an equivalent LTL formula, but even for moderate sized LSCs the formulae grow prohibitively large. In this paper we elaborate on practically relevant subclasses of LSCs, namely bonded and time bounded, which don't require the full power of LTL model-checking. For bonded LSCs, a combination of observer automaton and fixed small liveness property and for additionally time bounded LSCs reachability checking is sufficient.

The Statemate Verification Environment supports requirement analysis and specification development of embedded controllers as part of the Statemate product offering of I-Logix, Inc. This paper discusses key enhancements of the prototype tool reported in [2,5] in order to enable full scale industrial usage of the tool-set. It thus reports on a successfully completed technology transfer from a prototype tool-set to a commercial offering. The discussed enhancements are substantiated with performance results all taken from real industrial applications of leading companies in automotive and avionics.

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