An abstract semantic model based on an augmented transition network (ATN) is developed for distributed multimedia systems. This model has the capabilities to model the multimedia presentations, multimedia database searching, multimedia browsing. Conditions/actions on each arc in an ATN are used to provide real-time control. The input for an ATN is a multimedia input string which provides an efficient means for iconic indexing of the temporal and spatial relationships of multimedia objects. An ATN and its subnetworks are used to represent the appearing sequence of multimedia objects. A probabilistic network-based mechanism that forms a distributed multimedia environment using information obtained from data mining techniques is developed. This distributed environment can organize heterogeneous data sources and utilize the data. Current and future research directions include:

• Data placement and retrieval for distributed multimedia systems.
• Data mining for the multimedia systems.
• Using middleware technologies (CORBA, DCOM, etc.) to construct distributed multimedia information systems.
• Multimedia communication protocol design.
• Multimedia server design.
• Synchronization for multimedia objects.
• Multimedia applications.