Virtual documents are hypermedia documents that are generated on demand in response to reader input. This paper describes a virtual document application that generates natural language explanations about the structure and behavior of electromechanical systems. The application, called DME, structures the interaction with the reader as a question-answer dialog. Each page of the hyperdocument is the answer to a question, and each link on each page is a follow-up question that leads to another answer. DME is a model-based virtual document generator; unlike conventional database front-ends that provide views onto data, DME dynamically constructs the document's content (i.e. coherent explanations in English) from underlying mathematical and symbolic models. DME-based virtual documents have been running on the WWW since late 1993. They are used to document engineered systems in support of collaborative design and simulation-based training.
In this paper we describe and demonstrate the DME application (with examples that run), and describe how it generates virtual documents on the web. We discuss the impact that model-based virtual documentation can have on the way technical documentation is authored and delivered.
1997 Academic Press Limited
1. Model-based virtual documentation
Virtual documents are hypermedia documents that are generated on demand from underlying information sources, in response to user (reader) input. Virtual documents look like conventional web documents; they can be displayed using standard document viewers and they can be embedded into other documentation webs. Once generated, they may be indistinguishable from hand-crafted webs. However, virtual documents go beyond static documents in several respects. As they are generated from the underlying information sources, they can provide answers to a wide range of potential information which need not be enumerated in advance (e.g. plethora of questions bounded by a query language and domain vocabulary). Virtual documents can present up-todate information in domains where static documents quickly become obsolete. Because they are dynamically created in response to input, they can adapt the presentation to the reader's particular information and communication needs. Neil Stephenson's A Β½oung ΒΈady's Illustrated Primer (Stephenson, 1994) is an example of a virtual document.