Online synchronization of replicated models

This paper reports about our use of model versioning mechanisms in the industrial project ConfNet. The ConfNet software is used to organize sessions and talks for medical conferences. In these medical conferences, the presenters come with PowerPoint files on USB memory sticks. The technical team checks the PowerPoint files for external references e.g. to images or videos and converts each presentation to a ppsx file. ppsx files are self contained and PowerPoint opens them in presentation mode directly. Presentations happen in parallel sessions in different rooms, cf. Fig. 1. For each session, ConfNet provides an HTML page listing the talks. This HTML page is shown in full screen mode. By clicking on a talk, the corresponding PowerPoint presentation is opened (directly in presentation mode) and after the talk we fall back to the session overview page. Each room has its own laptop and video projector. In principle, all rooms are connected to a site local network. However, as these conferences run in large hotels or conference centers, the network infrastructure is regularly subject to failures, e.g. when the hotel technician reconfigures some network switches because some guest has problems with internet access in some room. To deal with such network failures, the presentation laptops do not rely on a central server but all presentation files and all session HTML files are copied to the corresponding presentation laptops. The HTML page and the presentations are then accessed from the local disk.