MODELING OF MULTIMEDIA SERVICES USING THE TMO MODEL

This paper presents an approach to the implementation of networked mul timedia services using a real-time object model, named the time-trigge red message-triggered (TMO) model. The TMO (previously called RTO.k) m odel formalized earlier by Kim and Kopetz as a timeliness-guaranteed c omputing model has built up the foundation of our design methodology. We identified a generic structure of a multimedia service object syste m (MSOS) as a multimedia service programming paradigm. In the MSOS, th ere are two kinds of TMO's: Scenario-TMO and Protocol-TMO. Each Scenar io-TMO in an MSOS controls the flow of multimedia streams. A scenario is composed of a set of (time/message-triggered) methods. Communicatio ns between MSOS's are handled by the Protocol-TMO. To provide an MSOS execution environment, we have developed a middleware named the window s time-triggered message-triggered object system (WTMOS) on the top of the Windows 95/NT and the MuX platform. The MuX was developed by ETRI in Korea to support basic multimedia service interfaces in heterogene ous distributed systems. This approach facilitates the development of multimedia services by easy formalization of services and parameterize d service generation. In this paper, we describe the structure of the MSOS and the WTMOS.