Context-Aware Digital Documents Described in a High-Level Petri Net-Based Hypermedia System

As mobile computing becomes widespread, so will the need for digital document delivery by hypertextual means. A further trend will be the provision of the ability for devices to determine where they are, e.g., through the inclusion of GPS sensors, as will the need for devices to operate on heterogeneous networks. Consequently, hypertext systems supporting these devices will benefit if they also can become context-aware. In this research, we introduce caT (for Context-Aware Trellis), a context-aware hypertext model and associated tools, which supports flexible user (or agent) adaptation to changes in environmental information, such as time, location, bandwidth/cost, etc. Firstly a context-aware hypertext model is proposed by incorporating both high-level Petri net features and user-modeling into the previously-described Trellis hypertext model. Major features of the high-level Petri net that are being explored are structured tokens and flexible net description. Fuzzy knowledge (context) handling is supported by the integration of a fuzzy logic tool with the Petri net, and a flexible information presentation tool has been designed to support Web-based browsing of documents specified in the caT model. Additionally, authoring and analysis issues are explored to support structured authoring and verification of application models, respectively. A simple example, a university digital library, is introduced in the paper to explain the concept of the caT model.