Metadata

DESIRE: Development of a European Service for Information on Research and Education

Link Rater

The aim is to make relevant third-party quality ratings available to a user whatever resources they are accessing on the web. Currently such ratings are not widely available but it is hoped that demonstrations such as this will speed their creation. For example, we might expect a research institute to make quality statements about the numerous search engines available on the Web, when selecting a search engine for a particular purpose such quality statements could be made available to the user. The ratings would be available whether the user was viewing an actual search engine, an independently compiled list of search engines, or a list of the search engines used by a meta search engine.

The approach described here allows ratings to be made available at the click of a personal toolbar button. After turning the feature on, the user simply moves the mouse over a resource to get a rating for that resource which appears in another window. As browsers become more configurable (e.g. Netscapes use of XML to describe graphical components) it will be possible to display ratings within the browser window rather than in a separate window.

Getting Ratings in a Displayable Format

In order to be able to display ratings in a web browser window they must be converted into a displayable form. With browsers that support XML with style sheets it will be possible to display RDF/XML ratings directly.

Currently, the simple approach of converting ratings to HTML is used. The script used to retrieve RDF/XML ratings via HTTP in ROADS for metadata management [GATEWAY] is also used here, it is called by a particular name to indicate that a displayable HTML page is the required result.

Requests of the form:

http://roads.ukoln.ac.uk/qualityratings/cgi-bin/metadataashtmlpage?http://www.ukoln.ac.uk

will return a displayable HTML page containing a rating of the resource if it is available from the contacted ratings bureau.

Accessing Ratings from Existing Resources

Once ratings are available as displayable HTML the next task is to make those ratings available.

This is achieved using a simple piece of Javascript in a personal toolbar button. The Javascript captures and processes events from the current document so that an action can be performed as the user moves over a hyperlink. In this way users can access quality information about a resource before they decide whether or not to visit the resource. The examples given have been tested using the Netscape 4.5 browser but a similar approach should apply to Internet Explorer.

The following Javascript has the required behaviour:

javascript:
function doMouseOver(e)
{
   window.open('http://roads.ukoln.ac.uk/qualityratings/cgi-bin/metadataashtmlpage?' 
   + escape(e.target.href),'Rating', 
   'width=500,height=300,toolbar=no,dependent=yes,alwaysraised=yes,
   directories=no,location=no,status=no,menubar=no,resizable=yes,
   scrollbars=yes');
};
document.captureEvents(Event.MOUSEOVER);
void(document.onmouseover=doMouseOver);

The above Javascript is broken over several lines for readability, it must actually appear within the 'Location' attribute of a bookmark, which may be a personal toolbar button.

To add this functionality to your (Netscape) browser drag the following link onto your personal toolbar:

Ratings

Or this one, to get have the ratings window raised when a rating is loaded:

Ratings

Click on the button to activate ratings for the page you are currently viewing. Move over a link to get a rating for that resource. Obviously, you will only get a rating if it is available. The ratings bureau you are accessing contains ratings for many of the resources that result from a search for the term 'cognitive' within the SOSIG Information Gateway. Note that this behaviour is completely independent of SOSIG and does not require any intervention at the SOSIG end.

Applications of Technique

The technique outlined above could be coupled with a mechanism for creating quality statements using ROADS to develop a personal database of quality information. As a user browses the web they make quality statements about resources which can later be viewed when they come across a link to a previously visited resource.

The above technique could be expanded to provide a group database, drawing on quality statements made by other members of a project group or organisation.

The technique could be used to provide accessibility information about resources. For example, an international society for the blind might make a database available describing the suitability of resources for the partially sighted. Rather than moving the mouse over a resource to get a quality rating the user might 'tab' to that resource and rather than displaying the rating in a window the rating might be spoken.

In all of the above scenarios, placing ratings in a ratings bureau makes those ratings accessible to other applications. For example, a particular quality attribute might be used to determine whether a resource should be added to a directory of resource for a particular research area.

References

[GATEWAY] - ROADS for Web Site Metadata Management - http://www.ukoln.ac.uk/metadata/roads/metadata-mgmt/mdmgmt.html

[Up to: DESIRE: Quality Ratings Implementation ]

Maintained by: Tracy Gardner of UKOLN, the UK Office for Library and Information Networking, University of Bath.
Document created: 19-Apr-1999.
Last updated: 15-Jun-1999.

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