The products and results of this work include general models, specific software for implementing these models, a set of demonstrational interconnections for demonstrating the capabilities of the models, evaluation of the research, and videos/reports describing the above.
As mentioned before, we will develop data, user-interface, coupling, real-time, replication/migration, and bus control models. The data model will include capabilities to define and translate between the data objects of the bus clients (that is, the interoperating applications). In particular, it will include capabilities to support user-defined types and inheritance. It will be portable in that will be supported on multiple heterogeneous operating systems and hardware. As mentioned before, we currently plan to use the Java data model as the basis of our work. The user-interface model will define and translate between the user interfaces of the bus clients. It will include capabilities to define not only traditional user-interface objects such as text buffers, forms, and tables but also non-traditional VE user-interfaces.
The coupling model will link single and multiuser interactive applications so that their users can collaborate with each other. It will include a variety of submodels including session management, awareness, sharing, concurrency control, and access control models. Session management will allow users to enter into joint sessions and will keep track of the various sessions in the system. Awareness will allow users to share information about each other using textual/audio/video streams. Sharing will allow semantic and view objects created for different users to exchange state. Concurrency and access control will protect users from executing inconsistent/unauthorized actions.
All of these models will support a wide range of policies -in particular they will define the policies supported by the target clients we propose to interface. It will support various degrees of sharing including sharing of semantic data, user-interface views, and positions of users within VE views. Moreover, these models will create global policies out of local client-specific policies. For instance, the session management objects will create global session management out of local session management provided by the interfacing clients.
The real-time model and replication/migration models will enable real-time collaboration. The real-time model will perform network and OS scheduling to ensure that real-time coupling needs of multimedia and VE environments are met. This replication/migration model will dynamically replicate/migrate portions of the bus and clients at the sites of users accessing them. For instance, it will replicate real-time services at the sites of the interacting users and migrate a lock object to the site of the user with the lock.
The bus security model will protect the operations on the bus. In particular, it will determine which clients can connect to the bus, which bus services they can use, and which services they can extend.