Xspect: Bridging Open Hypermedia and XLink

This paper evaluates the XLink format in comparison with other linking formats. The comparison is based on Xspect, an implementation of XLink. Xspect handles transformation between an open hypermedia format (OHIF) and XLink, and the paper discusses this isomorphic transformation and generalises it to include another open hypermedia format, FOHM. The Xspect system, based on XSLT and Javascript, provides users with an interface to browse and merge linkbases. Xspect supports navigational hypermedia in the form of links inserted on the fly into Web pages, as well as guided tours presented as SVG. Xspect has two implementations: one server-side and one running on the client. Both implementation provide the user with an interface for the creation of annotations. The main result of the paper is a critique of XLink. XLink is shown to be a format well suited for navigational hypermedia, but lacking in more advanced constructs. More problematic are the issues regarding large-scale use, such as evaluating validity and credibility of linkbases, and ensuring general support for a format as flexible as XLink.