Protocol for Web Description Resources (POWDER) Working Group - Publications
The purpose of the Protocol for Web Description Resources (POWDER) is to provide a means for individuals or organizations to describe a group of resources through the publication of machine-readable metadata, as motivated by the POWDER Use Cases [USECASES]. This document details the creation and lifecycle of Description Resources (DRs), which encapsulate such metadata. These are typically represented in a highly constrained XML dialect that is relatively human-readable. The meaning of such DRs are underpinned by formal semantics, accessible by performing a GRDDL Transform.
This document underpins the Protocol for Web Description Resources (POWDER). It describes how the relatively simple operational format of a POWDER document can be transformed through two stages: first into a more tightly constrained XML format (POWDER-BASE), and then into an RDF/OWL encoding (POWDER-S) that may be processed by Semantic Web tools. Such processing is only possible, however, if tools implement the semantic extension defined within this document. The formal semantics of POWDER are best understood after the reader is acquainted with the Description Resources [DR] and Grouping of Resources [GROUP] documents.
The Protocol for Web Description Resources (POWDER) facilitates the publication of descriptions of multiple resources such as all those available from a Web site. This document describes how sets of IRIs can be defined such that descriptions or other data can be applied to the resources obtained by dereferencing IRIs that are elements of the set. IRI sets are defined as XML elements with relatively loose operational semantics. This is underpinned by the formal semantics of POWDER which include a semantic extension, defined separately. A GRDDL transform is associated with the POWDER namespace that maps the operational to the formal semantics.
This document sets out the use cases and requirements that have motivated the development of the Protocol for Web Description Resources (POWDER). The use cases address social and commercial needs to provide information about groups of Web resources, such as those available from a Web site, to aid the annotation and/or personalization of content for end users in varying delivery contexts.
POWDER — the Protocol for Web Description Resources — provides a mechanism to describe and discover Web resources and helps the users to make a decision whether a given resource is of interest. There are a variety of use cases: from providing a better means to describing Web resources and creating trustmarks to aiding content discovery, child protection and Semantic Web searches.
There are two varieties of POWDER: a complex, semantically rich variety, called POWDER-S, and a much simpler version, just called POWDER, which is intended as the primary transport mechanism for Description Resources. POWDER-S can be generated automatically from POWDER.
The document describes and presents test cases for the Protocol for Web Description Resources (POWDER). The test cases aim to indicate the correct formats of POWDER documents and illustrate various crucial aspects on the usage of POWDER documents, such as locating a document and infering information from it.