The Internet provides a universal platform for large-scale distribution of information and supports inter-organizational services, system integration, and collaboration. Use of multimedia documents for dissemination and sharing of massive amounts of information is becoming a common practice for Internet-based applications and enterprises. With the rapid proliferation of multimedia data management technologies over the Internet, there is growing concern about security and privacy of information. Composing multimedia documents in a distributed heterogeneous environment involves integrating media objects from multiple security domains that may employ different access control policies for media objects. In this paper, we present a security model for distributed document management system that allows creation, storage, indexing, and presentation of secure multimedia documents. The model is based on a time augmented Petri-net and provides a flexible, multilevel access control mechanism that allows clearance-based access to different levels of information in a document. In addition, the model provides detailed multimedia synchronization requirements including deterministic and non-deterministic temporal relations and incomplete timing information among media objects.

We highlight major technical requirements for designing and developing future distributed multimedia information systems using Internet technology. The key requirements of this system are to allow users to access and search and to communicate multimedia documents consisting of text, audio, video and images. We emphasize the role of object-oriented technology for information management and real-time communication protocols to guarantee QoS. We present a reference architecture for a Web-based real-time distributed multimedia system which integrates enabling technologies including real-time streaming, multimedia indexing and searching and distributed object management.

We propose a dynamic bandwidth management scheme for asynchronous LANs that uses the concept of time division multiple access (TDMA). The scheme is to ensure quality of service (QoS) for multimedia applications. Significant performance improvement is observed through experimental results. In particular, the transmission rates for multimedia hosts improve significantly with low jitter variations in media streams. We also propose a framework for graceful degradation of play-out quality of multimedia objects in case the LAN's total capacity is not sufficient to meet the overall demand.

The authors present a multimedia management system that supports creation, storing, indexing and presentation of complex multimedia objects. An object-oriented data model is proposed to capture the content, spatial and temporal semantics of multimedia data. Based on this model, they design a query processor to perform multi-dimension search on multimedia data.