Informatisches Kolloquium WiSe 2001/2002

Prof. Dr. Kaj Grønbæk
Universität Århus

Open Hypermedia: Supporting Users to Link, Annotate and Organize the Web

This talk discusses an open hypermedia approach to provide external links, annotations, collections and guided tours to provide meta-data and structures for arbitrary Web resources. The talk gives a quick overview of open hypermedia research. Then it presents the open hypermedia work at University of Aarhus, which has materialized in a number of prototoypes such as Devise Hypermedia, WebVise, Arakne, Ariadne, Open Fluid Annotations, Manufaktur/Topos. A common basis for the prototypes that operate on the Web is an XML based data format, called Open Hypermedia Interchange Format - OHIF, representing open hypermedia structures. OHIF resembles Xlink with respect to its representation of out-of-line links, but it goes beyond XLink with a more rich set of structuring mechanisms, including e.g. composites. Moreover OHIF includes an addressing mechanisms (LocSpecs) that goes beyond XPointer and URL in its ability to locate non-XML data segments. With e.g. the Webvise system, OHIF structures can be authored, imposed on Web pages, and finally linked on the Web as any ordinary Web resource. Following a link to an OHIF file automatically invokes a Webvise download of the hypermedia structures and related Web content decorated with external notes and links will be displayed in the browser. The Webvise system also provides support for users to create, manipulate, and share the OHIF structures together with custom made web pages and MS Office 2000 documents on WebDAV servers. The talk will present the Webvise system and discuss some use experiences.