17.3 Application Structure

As has been mentioned before CYBERMAP is used for two purposes:

• The map is always in relation to the actual location of the user in the hyperdocument, i.e., it shows users where they are in the document. This can easily be implemented by highlighting the actual hyperdrawer.
• It shows the user where to go[18]. Based on the interests of the user CYBERMAP shows the user other nodes of potential interest. Using a DOI-function (DOI = Degree Of Interest [19]) the most interesting subset of nodes is selected.

The content analysis of the document is based on an index. Ideally an index is already available in the document. Otherwise an index is generated using automatic indexing techniques as described in chapter 1.

Figure I.90 Overview of the CYBERMAP system architecture

The algorithm for the generation of the overview map has to satisfy the following basic requirements:

• Every node must have its place in the overview map. If the user jumps from any node to the CYBERMAP, there must be a well defined place for the representation of this node on the map.
• Based on a contents analysis of the nodes related nodes are grouped together into the same hyperdrawer.
• Because of ergonomic and cognitive aspects the distribution of the nodes into the hyperdrawers has to be approximately well-balanced. Every hyperdrawer must have approximately the same number of nodes.
• Repeated runs of the algorithm must deliver the same CYBERMAP representation for the same set of boundary conditions (repeatability). The algorithm must also be resistant to small changes in the boundary conditions (stability). Small changes to the user profile should only result in small changes to the CYBERMAP.