Open and Reconfigurable Hypermedia Systems: A Filter-Based Model

The need for open hypermedia systems has been well-argued by various authors. In this paper we discuss the Microcosm model for open hypermedia and show how filters have been used to extend this model both for greater efficiency and to make it totally reconfigurable. This enables users to tailor the functionality of the system to meet their own requirements, for example to select different sets of links, or to add navigation tools. The implementation of a management system for filters is described, and examples of how it has been used to extend the functionality of the model are presented, in particular the use of filters to design and implement a set of navigation tools for Microcosm. This latter case study demonstrates the power and flexibility of the filter-based model since all navigation tools for the system can be implemented as filters. The filter technology is discussed in the context of Microcosm but can be generalised to other hypermedia systems.