THE AMSTERDAM HYPERMEDIA MODEL

This chapter presents the Amsterdam hypermedia model (AHM), a general framework that can be used to describe the basic constructs and actions common to a wide range of hypermedia systems. The AHM is presented in the context of the Dexter model's hypertext technology and terminology. This is done because hypertext is—in the time scale of information technology—a relatively mature discipline, with a well-defined model of general system behavior. The AHM is developed as an extension to the Dexter model to capitalize on its contributions to understanding hypertext systems. The AHM extends the Dexter model by adding to it the notions of time, high-level presentation attributes, and link context. A portion of this extension is based on the basic aspects of the CMIF multimedia document model. By combining the relevant aspects of the Dexter and CMIF models, the existing notions of hypertext presentations are taken and the implementation-independent behavior model of multimedia found in CMIF are added to these. Through the use of the CMIFed editor, a collection of hypermedia presentations have been created that approximate the richness of the full model, and researchers continue to investigate new ways of providing better implementation support for hypermedia. The novelty of the CMIFed supported approach to hypermedia is that the underlying structure can be freely manipulated, unlike many current multimedia authoring systems. This allows for quick and easy creation, copying, and altering of presentations.