Web team builds links

An award-winning university research team has linked with a hypermedia company to develop its prototype of an industrial strength system to open up the closed domain of the World Wide Web.

The Southampton University team and Multicosm Ltd, based at Chilworth Research Centre near the university, believe they have the solution to the Web's fundamental problems. The system they are developing can be used in both Internet and Intranet environments.

The problem with the Web is that an HTML document has a fixed set of links - in effect it is a closed hypermedia system. To provide other sets of links from the document for different applications, or even a view that changes within a single application, multiple versions of the document must be maintained, according to David De Roure who leads the distributed hypermedia team in the Multimedia Research Group in the department of electronics and computer science.

Also if a document being pointed to is changed or deleted, all documents that contain links to that document must be modified. All over the Internet there are thousands of dead links. And HTML is the only text document format that supports links. It is not possible to make links that come from other formats. A user can follow links through documents only as long as the links are there.

The team has built the Distributed Links Service, based on the multiple award-winning Microcosm application to address this problem. The power of the service comes from its ability to allow the user to improve the Web page they request by adding their own configured links.

The service functions as a proxy server where the user requests a page from any site on the Web using a standard browser. The DLS pulls back the page and adds links on the fly from "link databases" before sending it to the user. When a Web server hosting the DLS software receives, for example, a "followlink" request for a text selection they have made, a CGI script gathers together a number of link databases to try to satisfy the request.

The DLS can be used to add value to the personal work of a user in an Intranet by allowing links to be followed from word-processor documents, spreadsheets or databases.

The DLS provides flexibility in specifiying a "source anchor": this means that a single link to a destination may appear in many places at once, which adds useful features for the hypertext author.

Future DLS servers will feature text retrieval facilities, the ability to use a custom configuration of link databases, improved concurrency control, and better support for personal link databases where users may store their own links.

Peter McManus, Multicosm director, said: "We are making an early commitment to this ongoing university research project to underline its potential and we will be looking for other partners to further develop the service which we believe has great potential, particularly in Intranet environments."

An online tutorial and a version of the DLS are available for download at http://wwwcosm. ecs.soton.ac.uk/ dls/dls.html.