Specification of (Parts of) a Lip-Sync Protocol Using HyCharts

This paper presents the specification of some parts of a lip-synchronization protocol using HyCharts [GSB98]. The specification is based on a timed automata model for the protocol presented in [BFK + 98]. The primary motivation of this work is to examine the utility of HyCharts for problems in the multimedia field, in particular in comparison to timed automata [AD94]. 1 Introduction HyCharts consist of two modular, visual description techniques for the specification of hybrid, i.e. mixed discrete and continuous, systems. HyACharts are used for the specification of the system architecture and HySCharts specify the components' behavior. HySCharts can be seen as a hybrid extension of the Statechart variant ROOMcharts [SGW94]. The basic step of this extension is to annotate every state with an activity which specifies how continuous variables evolve when control is in the respective state. [GSB98] introduces HyCharts and [GS98] presents the underlying theory in more detail. The pu..