Formal models for the description of timed behaviors of multimedia and hypermedia distributed systems

This paper presents two modeling approaches that can be used as a formal basis for designing distributed multimedia and hypermedia systems. Using these approaches, users and designers are able to express formally their multimedia and hypermedia synchronization and time requirements. The two different models considered are Hierarchical Time Stream Petri Nets and RT-LOTOS. It will be shown that both models, starting from a different formal basis, are of interest as they possess complementary advantages and can then be used at different stages of the system life cycle. For instance, HTSPN provides an user-friendly graphical specification framework, whereas RT-LOTOS offers an extensive simulation and validation framework applicable to specifications derived from HTSPN.