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Protocol for Web Description Resources (POWDER): POWDER-S Vocabulary (WDRS)

Protocol for Web Description Resources (POWDER): POWDER-S Vocabulary (WDRS)

8 November 2010

Editors:
Andrea Perego, Università degli Studi dell'Insubria
Stasinos Konstantopoulos, Institute of Informatics & Telecommunications (IIT), NCSR
Phil Archer, Institute of Informatics & Telecommunications (IIT), NCSR (formerly at FOSI)

This document is also available as a non-normative RDF Schema.

Copyright © 2007 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark and document use rules apply.


Abstract

This is the namespace document for the POWDER-S vocabulary, part of the Protocol for Web Description Resources. Although this document sets out the domain and range of each term, their full definitions are to be found in other documents in the set, notably the Description Resources document [DR] and the Formal Semantics document [FORMAL].

Status of this document

This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.

This document describes the POWDER-S schema which has the namespace http://www.w3.org/2007/05/powder-s#. It was developed by the POWDER Working Group which does not expect to publish further updates. However, this document has no formal status (it is neither a W3C Recommendation nor a Working Group Note) and future changes, typically in the form of corrections, are possible. Such a correction has been made. Previously (a version dated 30 April 2009) an erroneous range restriction was applied to the describedby property. This has been removed.

Please send comments about this document to [email protected] (with public archive).

Publication of this document does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.

Table of Contents

1 Introduction
1.1 Namespaces
2 The Vocabulary Terms
2.1 Classes
2.1.1 Class Document
2.1.2 Class Processor
2.2 Properties
2.2.1 Property text
2.2.2 Property issuedby
2.2.3 Property matchesregex
2.2.4 Property notmatchesregex
2.2.5 Property hasIRI
2.2.6 Property tag
2.2.7 Property notknownto
2.2.8 Property describedby
2.2.9 Property authenticate
2.2.10 Property validfrom
2.2.11 Property validuntil
2.2.12 Property logo
2.2.13 Property sha1sum
2.2.14 Property certified
2.2.15 Property certifiedby
2.2.16 Property supportedby
2.2.17 Property data_error
2.2.18 Property proc_error
2.2.19 Property error_code
Acknowledgements
References

1 Introduction

The Protocol for Web Description Resources (POWDER) allows metadata to be associated with groups of resources such as those found on a Web site. Its main 'unit of information' is the Description Resource (DR), one or more of which are contained in a POWDER document. Processing such a document yields RDF triples describing the resources that are within the scope of the DRs. POWDER documents are written in XML and have relatively loose semantics, however, a GRDDL transform, associated with the root namespace, renders the data in RDF/OWL with more formal semantics.

An RDF vocabulary is defined to support Semantic POWDER, or POWDER-S encoding, of Description Resources. This is the namespace document for that vocabulary. Although this document sets out the domain and range of each term, their full definitions are to be found in other documents in the set, notably the Description Resources document [DR] and the Formal Semantics document [FORMAL].

1.1 Namespaces

The POWDER-S vocabulary namespace is http://www.w3.org/2007/05/powder-s# for which we use the prefix wdrs. All prefixes used in this document, together with their associated namespaces, are shown in the table below.

PrefixNamespacewdrs http://www.w3.org/2007/05/powder-s# rdf http://www.w3.org/1999/02/22-rdf-syntax-ns# rdfs http://www.w3.org/2000/01/rdf-schema# owl http://www.w3.org/2002/07/owl# dcterms http://purl.org/dc/terms/ xsd http://www.w3.org/TR/xmlschema-2/

2 The Vocabulary Terms

2.1 Classes

2.1.1 Class Document

RDFS Class

Label: POWDER document

Subclass of: http://www.w3.org/2002/07/owl#Ontology

In domain of: data_error

Defined in: http://www.w3.org/TR/powder-dr/#structure

A POWDER document.

2.1.2 Class Processor

RDFS Class

Label: POWDER processor

Subclass of: http://purl.org/dc/terms/Agent

In domain of: proc_error

In range of: notknownto

Defined in: http://www.w3.org/TR/powder-dr/#powderprocessor

A software agent able to process POWDER documents.

2.2 Properties

2.2.1 Property text

RDF Property

Label: text that may be displayed

Type: http://www.w3.org/2002/07/owl#AnnotationProperty

Defined in: http://www.w3.org/TR/powder-dr/#line13

This property provides a summary of the descriptorset that it annotates, suitable for display to end users.

2.2.2 Property issuedby

RDF Property

Label: issued by

Type: http://www.w3.org/2002/07/owl#AnnotationProperty

Defined in: http://www.w3.org/TR/powder-dr/#line3

This property denotes the author of a POWDER document.

2.2.3 Property matchesregex

RDF Property

Label: matches regular expression

Type: http://www.w3.org/2002/07/owl#DatatypeProperty

Domain: http://www.w3.org/2000/01/rdf-schema#Resource

Range: http://www.w3.org/2001/XMLSchema#string

Defined in: http://www.w3.org/TR/powder-formal/#regexSemantics

See also: http://www.w3.org/TR/xpath-functions/#regex-syntax

This is the key 'include' property for IRI set definitions in POWDER-S. It is necessary to take account of the POWDER Semantic Extension to process this fully. The value is a regular expression that is matched against an IRI.

2.2.4 Property notmatchesregex

RDF Property

Label: matches regular expression

Type: http://www.w3.org/2002/07/owl#DatatypeProperty

Domain: http://www.w3.org/2000/01/rdf-schema#Resource

Range: http://www.w3.org/2001/XMLSchema#string

Defined in: http://www.w3.org/TR/powder-formal/#regexSemantics

See also: http://www.w3.org/TR/xpath-functions/#regex-syntax

This is the key 'exclude' property for IRI set definitions in POWDER-S. It is necessary to take account of the POWDER Semantic Extension to process this fully. The value is a regular expression that is matched against an IRI.

2.2.5 Property hasIRI

RDF Property

Label: has IRI

Type: http://www.w3.org/2002/07/owl#DatatypeProperty

Domain: http://www.w3.org/2000/01/rdf-schema#Resource

Range: http://www.w3.org/2001/XMLSchema#anyURI

Defined in: http://www.w3.org/TR/powder-formal/#oxRegexSemantics

This property is meant to be used in OWL2 instead of wdrs:matchesregex. It denotes the string data range corresponding to a set of IRIs.

2.2.6 Property tag

RDF Property

Label: tag

Type: http://www.w3.org/2002/07/owl#DatatypeProperty

Range: http://www.w3.org/2001/XMLSchema#token

Defined in: http://www.w3.org/TR/powder-dr/#tags

Property linking to a free-text tag which may include spaces.

2.2.7 Property notknownto

RDF Property

Label: not known to

Range: #Processor

Defined in: http://www.w3.org/TR/powder-dr/#powderprocessor

Property used in results returned from a POWDER Processor that has no data about the candidate resource. The value is the IRI of the processor.

2.2.8 Property describedby

RDF Property

Label: described by

Defined in: http://www.w3.org/TR/powder-dr/#semlink

An RDF property to exactly match the describedby relationship type introduced in [www.w3.org] and formally defined in appendix D of the same document, i.e. the relationship A 'describedby' B asserts that resource B provides a description of resource A. There are no constraints on the format or representation of either A or B, neither are there any further constraints on either resource.

2.2.9 Property authenticate

RDF Property

Label: authenticate

Defined in: http://www.w3.org/TR/powder-dr/#discover

A pointer to a document that describes how Description Resources created by a FOAF Agent or a DC Terms Agent may be authenticated

2.2.10 Property validfrom

RDF Property

Label: valid from

Type: http://www.w3.org/2002/07/owl#AnnotationProperty

Defined in: http://www.w3.org/TR/powder-dr/#certification

Provides a timestamp that a POWDER Processor may use when assessing trustworthiness of a POWDER document. Informally, a POWDER Processor should normally ignore data in the document before the given date.

2.2.11 Property validuntil

RDF Property

Label: valid until

Type: http://www.w3.org/2002/07/owl#AnnotationProperty

Defined in: http://www.w3.org/TR/powder-dr/#certification

Provides a timestamp that a POWDER Processor may use when assessing trustworthiness of a POWDER document. Informally, a POWDER Processor should normally ignore data in the document after the given date.

2.2.12 Property logo

RDF Property

Label: logo

Type: http://www.w3.org/2002/07/owl#AnnotationProperty

Defined in: http://www.w3.org/TR/powder-dr/#line13

Points to a graphic summary for the resources in a given class. Typically, it is a logo denoting conformance of a given (set of) resource(s) to a given set of criteria.

2.2.13 Property sha1sum

RDF Property

Label: SHA-1 sum

Range: http://www.w3.org/2001/XMLSchema#base64Binary

Defined in: http://www.w3.org/TR/powder-dr/#certification

Links to a Base64-encoded binary SHA-1 hash of the described resource. May be used by POWDER Processors when assessing trustworthiness of a DR.

2.2.14 Property certified

RDF Property

Label: certified

Range: http://www.w3.org/2001/XMLSchema#boolean

Defined in: http://www.w3.org/TR/powder-dr/#certification

A property that takes a Boolean value to declare whether the author of the data certifies the described resource.

2.2.15 Property certifiedby

RDF Property

Label: certified by

Type: http://www.w3.org/2002/07/owl#AnnotationProperty

Defined in: http://www.w3.org/TR/powder-dr/#certification

A property that links a resource to a POWDER document that certifies it.

2.2.16 Property supportedby

RDF Property

Label: supported by

Type: http://www.w3.org/2002/07/owl#AnnotationProperty

Defined in: http://www.w3.org/TR/powder-dr/#supportedBy

A property that links a POWDER document to some other data source that supports the descriptions provided.

2.2.17 Property data_error

RDF Property

Label: data error

Domain: #Document

Defined in: http://www.w3.org/TR/powder-dr/#ppErrorhandling

A property denoting a description of the specific error found in a given POWDER document.

2.2.18 Property proc_error

RDF Property

Label: processing error

Domain: #Processor

Defined in: http://www.w3.org/TR/powder-dr/#ppErrorhandling

A property denoting a description of the specific software error.

2.2.19 Property error_code

RDF Property

Label: error code

Range: http://www.w3.org/2001/XMLSchema#nonNegativeInteger

Defined in: http://www.w3.org/TR/powder-dr/#ppErrorhandling

A property denoting the code of any error encountered by the POWDER processor.

References

[FORMAL]
Protocol for Web Description Resources (POWDER): Formal Semantics, S. Konstantopoulos, P. Archer. This document is at http://www.w3.org/TR/powder-formal/
[DR]
Protocol for Web Description Resources (POWDER): Description Resources, P Archer, K. Smith, A Perego. This document is at http://www.w3.org/TR/powder-dr/

Acknowledgements

The editors duly acknowledge contributions made by all members of the POWDER Working Group.