Distributed virtual reality (VR) is a powerful technology that could accelerate aeronautical and space research. VR software that is accessible remotely by NASA researchers would allow them to interactively build and manipulate complex scientific models and merge these models with data. However, several technical problems must be resolved. Current communications protocols and VR platforms do not adequately synchronize multiple data streams, originated from multiple distributed sources. The synchronization problem occurs at three points: l) cell jitter at layer two in the OSI protocol stack, 2) network delay of communication links, and 3) establishment of temporal relationships for presentation of information. Asynchronous Transfer Mode (ATM) has been identified as the preferred protocol for the real-time, high bandwidth, mixed-traffic type transmissions inherent in distributed VR applications. But ATM network specifications are insufficient for synchronization of aggregated, mixed streams of data. A middleware system for a distributed VR application will be designed to provide this synchronization function. Research effort will focus the network delay associated with communications protocols. Overlays to these protocols will be the core of the middleware system. This system will synchronize data streams among multiple locations to support remote access to VR software and collaborative conferences.NASA researchers will be able to interactively conduct design and simulations activities remotely. Large databases such as those containing complex scientific modeling data will more accessible and can be use effectively for simulations of atmospheric conditions. The middleware synchronization system will support a wide variety of distributed VR, telerobotic, and multimedia applications for research, training, business, and entertainment. The middleware will also decrease the costs associated with the transmission of real time, high bandwidth, interactive applications like VR. Experts estimate the number of potential VR users at 140 million plus.
Keywords: Phase_I, NASA, Abstract, FY94
