Mediaware: a distributed multimedia computing environment and formalism based on interoperable Petri net

With increasing frequency, distributed Multimedia (MM) computing environments and applications are being introduced into different disciplines. In order to maximize the utilization of multimedia resources, multimedia environment needs to be architectured as an open system of distributed and interoperable media objects. Systems of this kind are becoming increasingly large and complex. Formal models are therefore highly desirable, however, the formalization of multimedia environments has not been adequately addressed to date. In this dissertation, I am proposing: MediaWare as a distributed multimedia computing environment architecture based on state-of-the-art distributed object computing, Interoperable Petri Nets (IPN) as an extension to the high level Petri nets with interoperability notion and the interface construct, and finally, MediaWare as a formalization of distributed multimedia environment based on IPN. The distributed object computing (DOC) paradigm, as specified by the Object Management Group's Common Object Request Broker Architecture (OMG-CORBA), is adopted as a basis of MediaWare architecture. MediaWare, as a multimedia environment, is architectured as a layered approach with seven layers. These layers are: Multimedia Application layer, Quality-of-Connection (QoC) layer which consists of user interaction, Quality-of-Service (QoS) and synchronization requirements, Interoperable Virtual Connection Protocol (IVCP) layer, Objects Database layer, Object Request Broker (ORB) layer, Interface Definition Language (IDL) Mapping layer, and finally, the Object Implementation layer. MediaWare features interoperable media objects through the virtual connection protocol. As such, MediaWare supports interactive, synchronized, and timed-based media in a heterogeneous environment. Interoperability as a distinct feature of MM applications has not been addressed in the context of Petri nets. Therefore, this dissertation defines the Interoperable Petri Net (IPN) as a new extension to the High-Level Petri Net (HLPN). In particular, it provides a formal definition of IPN, the mapping from IPN into HLPN algorithms, and the Virtual Connection Protocol (VCP), which adds the interoperability among IPN (media) objects. By mapping IPN into HLPN, the hierarchical reachability graph can be obtained. Furthermore, in this dissertation, I will show that the IPN can be considered as an object-oriented extension to HLPN. IPN is used to model MediaWare. MediaWare, as a distributed multimedia computing environment formalism, includes the formalization of: inter-stream and intra-stream synchronization, temporal relations among media objects' intervals, user interactions, Quality-of-Services (QoS), and MediaWare's object life cycle. We believe that MediaWare is one step toward analyzing, formalizing and standardizing the distributed MM environments. Furthermore, we believe that IPN can easily be used to model several emerging technologies such as: Concurrent Object Computing, Heterogeneous Computing (HC), Concurrent Engineering (CE) and Computer-Supported Cooperative Work (CSCW) and Groupware applications.