XML News from Friday, September 28, 2007

The W3C POWDER working group has published three new working drafts:

According to the first,

The Protocol for Web Description Resources (POWDER) facilitates the publication of descriptions of multiple resources such as all those available from a Web site. These descriptions are attributable to a named individual, organization or entity that may or may not be the creator of the described resources. This contrasts with more usual metadata that typically applies to a single resource, such as a specific document's title, which is usually provided by its author.

This document sets out how Description Resources (DRs) can be created and published, whether individually or as a bulk data, how to link to DRs from other online resources, and, crucially, how DRs may be authenticated. The aim is to provide a platform through which opinions, claims and assertions about online resources can be expressed by people and exchanged by machines. POWDER has evolved from the data model developed for the final report [XGR] of the Web Content Label Incubator Group [WCL-XG] from which we define a Description Resource as: "a resource that contains a description, a definition of the scope of the description and assertions about both the circumstances of its own creation and the entity that created it."

The method of defining the scope of a DR, that is, defining what is being described, is provided in a separate document: Grouping of Resources [GROUP]. Companion documents describe the RDF/OWL vocabulary [VOC] and XML data types [WDRD] that are derived from the Grouping of Resources document and this document, with each term's domain, range and constraints defined. As each term is introduced in this document, it is linked to its description in the vocabulary document. The POWDER vocabulary namespace is http://www.w3.org/2007/05/powder# for which we use the QName wdr.

POWDER takes a very broad approach so that it is possible for both the resource creator and third parties to make assertions about all kinds of things, with no architectural limits on the kind of thing they are making claims about. For example, medically proficient organizations might be concerned with properties of the agencies and processes that produce Web content (e.g.. companies, people, and their credentials). Equally, a 'Mobile Web' application might need to determine the properties of various devices such as their screen dimensions, and those device types might be described with such properties by their manufacturer or by others. Although the broad approach is supported, we have focused on Web resources rather than trying to define a universal labeling system for objects.