4TH-GENERATION HYPERMEDIA - SOME MISSING LINKS FOR THE WORLD-WIDE-WEB

World Wide Web authors must cope in a hypermedia environment analogous to second-generation computing languages, building and managing most hypermedia links using simple anchors and single-step navigation. Foll owing this analogy, sophisticated application environments on the Worl d Wide Web will require third- and fourth-generation hypermedia featur es. Implementing third- and fourth-generation hypermedia involves desi gning both high-level hypermedia features and the high-level authoring environments system developers build for authors to specify them. We present a set of high-level hypermedia features including typed nodes and links, link attributes, structure-based query, transclusions, warm and hot links, private and public links, hypermedia access permission s, computed personalized links, external link databases, link update m echanisms, overviews, trails, guided tours, backtracking and history-b ased navigation. We ground our discussion in the hypermedia research l iterature, and illustrate each feature both from existing implementati ons and a running scenario. We also give some direction for implementi ng these on the World Wide Web and in other information systems. (C) 1 997 Academic Press Limited.