Hypermedia – Introduction
1 Introduction
The issue of incorporating semantics into a hypertext network has been addressed before [Collier, 1987][Trigg & Weiser, 1986]. Rao and Turoff had proposed a general framework for hypertext functionality based on Guilford’s Structure of the Intellect Model [Rao & Turoff, 1990]. They had observed that as hypertext databases grow in size, they suffer from a lack of coherence due to ambiguity in meanings assigned to nodes and links. Hence, they proposed a framework which classified nodes into six different semantic types and links into twelve different types. Such a comprehensive framework would help designers develop better design metaphors and implementation models for hypertext systems. A first step in this direction is to develop an appropriate user interface which would reduce functional and system opacities.
A number of tools have been developed for hypertext navigation since Conklin addressed the issues of disorientation and cognitive overhead [Conklin, 1987]. These include graphical browsers, overview diagrams, web views, paths, trails, guided tours and tabletops, history lists, timestamps, footprints, bookmarks, backtracks, queries, embedded menus, fisheye views and roam and zoom techniques [Beard, 1987][Collier, 1987][Halasz, 1988b][Koved & Shneiderman, 1986][Nielsen, 1990a][Trigg, 1988][Utting & Yankelovich, 1989][Zellweger, 1989]. Authoring guidelines have also been proposed for the organization of information in a hypertext system [Thuring et al., 1991]. However, there has been no systematic and comprehensive approach towards the design of user interfaces for hypertext systems. This paper attempts to explore the application of a set of user interface design guidelines to the aforementioned hypertext framework.