Structured Authoring in a Unified Net-based Hypertext Model

作者先前基于Petri网的形式主义开发了超文本模型，称为Trellis。与其他超文本模型一样，Trellis表示信息片段以及将这些片段连接在一起的关系。Trellis的一个重要前提是，浏览超文本的行为应该被正式表示。浏览的正式描述不仅允许对文档的动态属性进行分析和验证，而且还通过提供简洁、明确和独立于实现的行为定义来标准化浏览的语义。在它的符号框架内，Trellis提供了通过超文本同步同时遍历不同路径的能力，并提供了将访问考虑因素合并到超文本中的能力，指定了可以证明仅对某些类型的浏览器可见的节点。Trellis是一个定时模型，允许指定事件延迟和持续时间以及系统生成的调用。研究者在这项研究中进行了两个主要项目。两者都是基于已经完成的Trellis超文本工作。首先是抽象表示方法的开发，这些方法允许将单一的统一超文本规范映射到适合许多不同超文本系统的文档中。这反过来又会导致基于在统一模型中转换和转换的不同超文本系统的交换方法。第二个是编写语言“实验室”，允许对超文本编写语言进行快速规范和评估。这些项目将产生既有理论意义又有实际意义的结果。

The authors have previously developed a model of hypertext, called Trellis, based on the formalism of Petri nets. As in other hypertext models, Trellis represents information fragments and the relationships that tie the fragments together. An important premise underlying Trellis is the claim that the actions of browsing a hypertext should be formally represented. A formal description of browsing not only permits analysis and verification of the dynamic properties of a document, but also standardizes the semantics of browsing by providing a succinct, unambiguous, and implementation-independent definition of behavior. Within its notational framework, Trellis provides the ability to synchronize simultaneous traversals of separate paths through the hypertext and the ability to incorporate access considerations into the hypertext, specifyingnodes that can be proven to be visible only to certain classes of browsers. Trellis is a timed model, permitting specification of event delays and durations as well as system-generated invocations. The investigators conduct two main projects under this research. Both are based on the Trellis hypertext work already accomplished. The first is the development of abstract representation methods that permit the mapping of a single unified hypertext specification into documents suitable for each of many different hypertext systems. This, in turn, can reesult in interchange methods for different hypertext systems based on translation into and out of the unified model. The second is an authoring language "laboratory" to allow the rapid specification and evaluation of hypertext authoring languages. The projects will produce results of both theoretical and practical interest.