Semantic Web Activity News

Stefan Schumacher has published a German translation of the RDFa Primer.

W3C launched today the RDFa Working Group, whose mission is to support the use of RDFa, a format for embedding structured data in Web documents. The Working Group's goals include making it easier to author RDFa, promoting continued adoption of the technology in HTML, XHTML, and XML, and helping developers create RDFa applications. The group is chartered to extend and enhance RDFa 1.0, including the specification of an API. The Working Group will also support the HTML Working Group in its work on incorporating RDFa in HTML5 and XHTML5 (as a followup on the the currently published Working Draft for RDFa 1.0 in HTML5).

The BBC has provided a W3C Semantic Web Use Case on how Semantic Web Technologies are used on some of the BBC’s Web Sites. The main characteristics of the BBC’s approach is to use the Web as a Content Management System. Sites like the BBC Music, BBC Programmes, or the BBC Wildlife Finder rely on external, publicly available datasets like Musicbrainz or Wikipedia; the BBC sites themselves show an aggregated view of this information, put in a BBC context. Furthermore, the BBC also creates Web identifiers for every item it has interest in; RDF representations of these Web identifiers allow developers to use the BBC’s data to build applications.

The W3C SPARQL Working Group has published a First Public Working Draft of SPARQL 1.1 Property Paths, which defines a more succinct way to write parts of basic graph patterns and also extend matching of triple pattern to arbitrary length paths. The group also published six updates, namely:

• SPARQL 1.1 Query adds support for aggregates, subqueries, projected expressions, and negation to the SPARQL query language.
• SPARQL 1.1 Update defines an update language for RDF graphs.
• SPARQL 1.1 Protocol for RDF defines an abstract interface and HTTP bindings for a protocol to issue SPARQL Query and SPARQL Update statements against a SPARQL endpoint.
• SPARQL 1.1 Service Description defines a vocabulary and discovery mechanism for describing the capabilities of a SPARQL endpoint.
• SPARQL 1.1 Uniform HTTP Protocol for Managing RDF Graphs describes the use of the HTTP protocol for managing named RDF graphs on an HTTP server.
• SPARQL 1.1 Entailment Regimes defines conditions under which SPARQL queries can be used with entailment regimes such as RDF, RDF Schema, OWL, or RIF.

W3C is organizing a Workshop on the Next Steps for RDF around June 2010; we will announce the exact dates and location as soon as possible.

Since its publication in 2004, the Resource Description Framework (RDF) has become the core architectural block of the Semantic Web. The standard is now widely deployed in terms of tools and applications. Due to this wide deployment, additional R&D activities, and the publication of newer standards (e.g., SPARQL, OWL, POWDER, and SKOS), a number of issues regarding RDF have come to the fore. Workshop articipants will discuss these issues and help determine whether it is time for a new version of RDF. W3C Membership is not required to participate in the Workshop, but each participant must be associated with an accepted position paper. The deadline for position papers is 29 March 2010; see the Call for Participation for more information.

Updates (including the exact date and location of the Workshop) will be added to the Call for Participation and will be announced on the Semantic Web Activity News Blog.

A new public wiki site has been set up at W3C, nicknamed “Semantic Web Standards Wiki” or SWSWiki. It is not the goal of this wiki to supersede other community wikis like Semanticweb.org or OWLED Wiki; instead it is to provide a “first stop” for more information on Semantic Web technologies, in particular on Semantic Web Standards published by the W3C. Communities around such standards are also welcome to use the Wiki for their purpose; as an example, and thanks to Antoine Isaac, the SKOS community has already begun creating its own specific pages. Essentially, the role of this Wiki is to be an alternative (and, at some point in the future, maybe a replacement) to the ESW Wiki at W3C, but concentrating on Semantic Web only and using Semantic Media Wiki as an underlying technology.

Some pages from the ESW wiki have already been copied to ESWWiki. For example, the old book list has been copied to SWSWiki Book page. The old ESW list of tools, as well as some related pages like the Commercial Product have also been copied; however, and in contrast to the book list, this was not simply a copy of the pages but a new structure was also created, making use of the possibilities of Semantic Media Wiki. As a result, each tool has its own, separate page (produced by a template) and different types of searches can be performed on the tool list to find the ones usable from, say, Python and relevant to OWL development. See the new tools‘ list for further details and the contributors‘ page if you also want to contribute. (No major change on the content of the tool descriptions have been made during this copy, although, in some cases, different texts referring to the same tool have been merged. Apologies if some mistakes have been made along the line.) Each tool also gained an automatic RDF description, thanks again to the possibilities offered by the Semantic Media Wiki.

This is an evolving Wiki. Evolving, meaning that new pages and new features will be added as time goes by; and Wiki, meaning that it relies on community contributions. Anybody having a W3C account (member or public) can and is welcome to contribute to the pages. General comments are also welcome (best is to send them to the Semantic Web Activity Lead, Ivan Herman, or discuss it on the SW IG).

W3C has published a set of URI-s to uniquely identify OWL 2 Profiles. These URI-s are needed for the upcoming SPARQL specification, but their usage can be more general and not bound to specific technologies.

The URI-s for the OWL 2 Profiles are:

• OWL 2 DL: http://www.w3.org/ns/owl-profile/DL
• OWL 2 EL: http://www.w3.org/ns/owl-profile/EL
• OWL 2 QL: http://www.w3.org/ns/owl-profile/QL
• OWL 2 RL: http://www.w3.org/ns/owl-profile/RL

Each of these URI-s can return, depending on content negotiations, XHTML+RDFa, RDF/XML, or Turtle content; the URI-s above with html, rdf, or ttl suffixes, respectively, can also be used to get to those versions directly.

W3C has published a set of URI-s to uniquely identify Semantic Web entailment regimes. These URI-s are needed for the upcoming SPARQL and RIF specifications, but their usage can be more general and not bound to specific technologies.

The URI-s for the various entailment regimes are:

• Simple Entailment: http://www.w3.org/ns/entailment/Simple
• RDF Entailment: http://www.w3.org/ns/entailment/RDF
• RDFS Entailment: http://www.w3.org/ns/entailment/RDFS
• D Entailment: http://www.w3.org/ns/entailment/D
• OWL Entailment with Direct Semantics: http://www.w3.org/ns/entailment/OWL-Direct
• OWL Entailment with RDF Based Semantics: http://www.w3.org/ns/entailment/OWL-RDF-Based
• RIF Entailment: http://www.w3.org/ns/entailment/RIF

Each of these URI-s can return, depending on content negotiations, XHTML+RDFa, RDF/XML, or Turtle content; the URI-s above with html, rdf, or ttl suffixes, respectively, can also be used to get to those versions directly.