17.7 Dynamic Linking with CYBERMAP
The CYBERMAP approach implements linking by similarity as described in chapter 10. Depending on the needs of the user new links are calculated as the CYBERMAP is updated after either a modification of the user profile or the original document base. CYBERMAP complements the existing linking structure to offer another perspective to a user-specified subset of cyberspace. It is in this sense complimentary to tools that visualize the linking structure such as our own Hiermap described in chapter 14, and most of the mapping tools described in chapter 11.
CYBERMAP does not make direct use of static links available in prefabricated hyperdocuments. These links are not used for the generation of the CYBERMAP for three reasons:
- The implementation of links is extremely system dependent. Every system implements its links different. For example, it is almost impossible to write a filter procedure that extracts all hard- and soft-wired links from any HyperCard stack because there are too many possibilities to implement linking in HyperCard. Systems like Hyper-G make this task much easier, because they store the links in external databases. On the web, there are many different ways to implement links, and the use of CGI scripts and Imagemaps makes it also near to impossible to extract all links automatically. As linking is now done on a world-wide scale, it also becomes prohibitively hard to keep a link database locally accessible and globally updated all the time.
- In order to offer a dynamically updated user dependent view of the document, the CYBERMAP structure is based on the concept of dynamic links.
- Because CYBERMAP does not directly use the link structure of the hyperdocument, the CYBERMAP concept is equally usable for hypertext documents and non-hypertext-documents.
The current web CYBERMAP implementation makes use of linking information in that keywords within the <A HREF> tag can be weighted much higher to compute the similarities.
Of course, the reader is free to dispense with the CYBERMAP navigation mechanism at any time and to browse in a hyperdocument using the original linking mechanisms of the hyperdocument.