1. TU e technische universiteit eindhoven / department of mathematics and computer science Information Systems Group – http://wwwis.win.tue.nl/~hera – hera@win.tue.nl – +31 40 247 27 33 HERA METHODOLOGY The Hera methodology distinguishes the following phases in the design of Web Information Systems (WIS) that automatically generate hypermedia presentations: Conceptual and integration design, where the Conceptual Model (CM) and Integration Model (IM) are constructed. CM specifies a unified (schema) view over the data (local sources). IM describes how to relate source data to CM. Both models are the core models of the Semantic Layer of the system. Application and adaptation design, where the Application Model (AM) defining the navigation view over CM and its adaptation behavior is constructed. AM is the core model of the Application Layer of the system. Presentation design, where the Presentation Model (PM) specifying the spatial layout and rendering of hypermedia presentations is constructed. PM is the core model of the Presentation Layer of the system. All models describe different aspects of the designed hypermedia presentation and are used by the HPG software for the automated generation of hypermedia presentations. Hypermedia Presentation Generation in WIS AUTOMATED PRESENTATION GENERATION In the HPG software the automated process of the presentation generation is based on the instantiation of the Hera models. It is started by a query on CM, and it consists of the main phases: Data retrieval and creation of a CM instance, which includes: generation and re-distribution of queries to local sources, and retrieval of local data and its integration into a CM instance. Presentation generation, which includes: unfolding and adapting the AM template (empty AM instance), generating an XSL stylesheet used in the following step for the instantiation of AM, instantiating the AM template with data from the CM instance, instantiating the PM template with data from the AM instance, and transforming the generated PM instance into a hypermedia presentation in end-user format (HTML or WML). SOFTWARE TOOLS AND IMPEMENTATION The presentation generation is implemented in the HPG tool that allows stepping and customizing (choosing CM, AM, changing user profile, etc.) the presentation generation process. The first generation tool is based on Java and XSL transformations (Saxon XSLT processor). The second generation HPG tool supports dynamic navigation (richer functionality) and it is implemented using a Java RDF API (HP Jena). CM Builder is a Visio solution that facilitates the construction of CM in a graphical way and exports it to RDFS. AM Builder is another Visio solution that supports the building of AM in a graphical way using the Hera graphical notation (similar to RMM). An AM diagram can be exported to RDFS. The diagram of the process of presentation generation within the system layers The designer can use the Visio based CM Builder (left) and AM Builder (right) An adaptation specification example within AM The user interface of HPG Generated presentations in HTML and in WML A presentation model example Hera