Automatic verification of hybrid systems: an audio control protocol

The work is concerned with formal approaches to specification and verification for a better development in systems design. Automatic verification is a solution for validating highly critical systems, like controlling robots or supervising electronical devices. Important efforts have been realized in industry and education for supporting its development. Nevertheless, technical problems keep arising due to the size of specifications, in some cases requiring too much effort to obtain some results. We present the specification of the EEL communication protocol, used by Phillips in its audio components. This protocol verifies the correct communication between an audio system and its remote control, and is a typical case for studying hybrid systems. Hybrid systems are specified by finite automata enriched with a set of real variables. Properties to prove are usually written in some temporal logic. Automatic verification tools solve the "model checking" problem: does property /spl pi/ hold in system S?. To solve difficulties associated to the size of systems, different tools have implemented techniques such as symbolic model checking, "on the fly" analysis, modularization and clock reduction. We believe that there are still ways to improve these tools: diminish redundancy in modelling, optimization for data management and storage, randomization of algorithms.