Currently the IRREAL senders transmit formatted text and vector graphics which may contain hyperlinks to each other (hypertext, hypergraphics). Information is structured as a directed acyclic graph of hyperdocuments and in each graph there is a specific starting point or root node. Figure 1 shows a screenshot of our hyperdocument authoring tool. One sender can send several hyperdocuments each of which has a list of user or group IDs assigned to it. Links can lead to elements (text or graphics) within the same document or to the root node of another document. In this way it is possible to broadcast information in different languages or, more generally, for different user profiles. Elements of one document can be reused in in all other documents which prevents the wasting of bandwidth by duplicating data, such as language independent graphics. All the documents are broadcast in a cycle and the relative probability of every element being broadcast is controlled by its relative importance value. A more detailed description of this probabilistic broadcasting scheme can be found in [2].
Figure 2: Screenshot of the hyperdocument browser software BrowsIR. The initial presentation only contains the floor plan with the exhibit in question. Then additional exhibits are displayed gray and as information comes in they turn black to signal that they are clickable. A perspective view of the current location can be chosen by selecting your own position (black dot).
Figure 2 shows some screenshots of a Palm Pilot simulator (Xcopilot) running our client software 'BrowsIR'.