Collaborative multimedia environments for problem-solving

A new method of designing collaborative multimedia environments for computer assisted problem solving is described. These environments support computer mediated interaction between multiple physically separated users joined by a communication network. Users interact using application specific models and objects, text, audio, video and graphics. Computer mediation enables both synchronous and asynchronous interaction, empowering users to transcend barriers of space and time. Proliferation of high performance multimedia workstations and high speed and capacity networks provides us with the mechansim to realize real-time multi-user tools for computer-supported cooperative work. However, development and deployment of groupware, and consequent popular adoption, has been impeded by the absence of general models and enabling infrastructures. This thesis is a step towards developing formalisms for designing and implementing collaborative systems and groupware. Requirements for the infrastructure from the developer\u27s and the user\u27s perspectives are identified and previous work is surveyed to highlight lessons learned, and to isolate desired features that are lacking. Application models that are amenable to distributed and collaborative operation on heterogeneous platforms are then developed. In these models, software tools consist of contexts that are characterized by a state that is modified by events and can be thought of as event driven distributed data flow machines. These models are used to build an enabling infrastructure for rapid prototyping of real-time groupware. Mechanisms for routing events to different states and contexts are provided, as are mechanisms for distribution functionality like synchronous and asynchronous remote procedure calling, and collaboration functionality like session control, interaction control, and high level access regulation. Identified shortcomings of extant work are overcome and mechanisms to implement policies derived from related research efforts are provided. The solution is justified from the technical and human factors viewpoints. In this dissertation, the models and the infrastructure are described. Details of an implemented collaborative multimedia environment are presented, demonstrating the viability of the infrastructure. Possible applications of this technology are identified, and the facilitation of groupware prototyping by the model and infrastructure is described. Open issues and possible research directions are identified