Reactive process networks

Data flow process networks are a good model of computation for streaming multimedia applications incorporating audio, video and/or graphics streams. Process networks are concurrent processes communicating streams of data through FIFO channels. They can be executed efficiently and determinately on multiprocessor platforms. However, such stream processing applications are becoming more dynamic, often requiring run-time reconfigurations. Moreover, stream processing is not always an application on its own, but may be a component of a larger application. This application, e.g. a game application, may be control oriented and event driven; events may interact with the streaming component and (re)configure it. In order to capture the interaction between reactive and streaming components as well as reconfiguration in dynamic stream processing, we introduce in this paper a formal, operational and compositional semantics of so-called reactive process networks. This operational semantics can serve as the basis for programming models that allow the programming of streaming components interacting with reactive system components and their reconfigurations. It also supports the construction of analysis and synthesis tools for dynamic streaming multimedia applications. It allows the integration of reactive behaviour in process networks as general as Kahn process networks, but it is also suitable for more restricted and efficient classes of process networks