July 28, 2006

Turorial RDF, RDFS and SPARQL using CORESE

Semantic web tutorial gives a quick tour of RDF, RDFS, SPARQL and Rules. It was designed as a hand-on-keyboard introduction to the basics of RDF model, RDFS semantics for lightweight ontologies, SPARQL query language for RDF graph bases and production rules for knowledge factorisation in semantic web annotation bases. http://www-sop.inria.fr/acacia/soft/corese/tutorial.php Categories Applications and Demos | Ontology-based searching | XML and RDF | dissemination
Posted by fgandon at 01:03 PM | Comments (0)

December 22, 2004

Thank you and goodnight!

SWAD-Europe finally winds up this week as we send all our documents off to the Commission and settle down for a little rest.

Our reworked website will remain on the W3C site and now contains SVG and raster images of the postcard and tshirt design, which our designer Liz Turner has made available under a non-restrictive Creative Commons License for others to use. The site also contains our final report and complete text of all the deliverables. The wiki we used will stay put and this weblog will continue to be used by the SWBP working group.

We'd like to thank everyone who contributed to the project from the five partners W3C, ILRT, HP Labs, CCLC and Stilo or as contractors; and also everyone who joined in from the Semantic Web community, through the public and thesaurus mailing lists, the wiki and weblog, IRC discussions and workshops. You made the project successful and lots of fun to work on. We'd also like to thank Brian Macklin and Hans-Georg Stork at the European Commission for being patient and helpful.

A final word on tshirts: we've very much enjoyed playing semantic santa sending them all out but we know we missed people out who've done excellent work and we feel pretty bad about that. We have one or two left so if we offered you one and it didn't arrive, or you feel left out mail libby.miller@bristol.ac.uk and we'll see what we can do: but no promises, sorry.

All the best for the holidays,

Libby and Dan Categories dissemination
Posted by lmiller2 at 09:19 PM | Comments (0)

August 01, 2004

Multilingual Semantic Web work

Following the successful spanish-language workshop in Spain, the SWAD-E project will be taking advantage of an opportunity to participate in a workshop in Argentina in August. This continues the outreach to non-english speaking developers that is one of the goals of the project.

Categories dissemination

Thanks to the Universidad Kennedy of Buenos Aires, Diego Ferreyra of the Argentine government, Eva Méndez, Leandro Mariano López, and others, the workshop bring developers together to discuss their work, and examine how to learn from the SWAD-E project to further development of the Semantic Web. The workshop will take advantage of two conferences taking place in Buenos Aires bringing interested participants from around South America who will be able to participate in the workshop.

Further visibility of work being done in non-english languages, such as spanish and french, should increase the quality of work taking place across Europe, not just in the english-speaking countries of the world. The investment made by the SWAD-E project in this area has already shown important returns in increased dissemination of work in a number of languages, and in collaboration that has improved the quality of individual projects.

There are a number of presentations and documents in languages other than english linked from the project home page. Other resources include the recent workshop on "metadata in a multilingual world", and the geographic information project being developed primarily in french.

Posted by charles at 01:45 PM | Comments (0) | TrackBack

Le Web Semantique à Montréal...

An occasional meeting of W3Québec, a group who are interested in web standards in francophone Canada, was the opportunity to talk about the Semantic Web. It motivated some work on translation of existing resources, and hopefull also some more development by francophones, which can only help dissemination across Europe and particularly french-speaking Africa.

Categories dissemination

Material produced for the session included a french translation of Hera, a tool designed to help assess web accesibility and produce results in RDF, as well as a french version of my "Introduction to RDF via CWM" (I really should make an english version, although there is plenty of material in english already).

Thanks to all who participated, especially Karl Dubost of W3C for his lively explanations and re-explanations, Monique and Alex for logistics support, and above all Catherine Roy, who organised the whole thing.

Posted by charles at 05:12 AM | Comments (0)

June 29, 2004

Spanish Language Workshop

The first SWAD-E workshop in a language other than english took place in Madrid on 13 June, in Spanish. As well as José Kahan and I from SWAD-E, two of the people who signed up for the workshop presented their work - José Ramón Perez Agüera and Emmanuelle Gutiérrez y Restrepo.

The feedback suggests that it was a success, and it would be nice to see more developer workshops taking pace in different languages. It seems particularly important to me, since many people who live in a non-english-speaking country do a lot of work in english. This can help promote development in english, but it can also make experienced developers seem inaccessible to people who are their natural colleagues.

Categories dissemination | trip report

A formal report in english (also published in spanish) describes the detail of the presentations that were given. I thought a highlight was the review of SKOS against other thesaurus systems, and explanation of why it made a good choice, combined with the "happy customer" explanation of how to implement it with Jena.

But then, for me the highlight was actually getting the day to happen. Many thanks are due to many people - as well as those named, Eva, Inkel, Ismael, and Javier all deserve a special mention for their efforts to make sure that their work build bridges between communities who might otherwise be divided by the languages they happen to speak. More than simply teaching everyone Esperanto, there are clear and obvious benefits from this little bit of motivation already appearing.

Posted by charles at 02:12 AM | Comments (0) | TrackBack

June 11, 2004

ADTF: Creative Commons

URL: http://creativecommons.org/
Date created: 2001

Description:
Creative Commons has developed a Web application that helps people dedicate their creative works to the public domain or retain their copyright while licensing them as free for certain uses, on certain conditions. Creative Commons are designed for a variety of creative works: websites, scholarship, music, film, photography, literature, courseware, etc. To this end, they have developed metadata that can be used to associate creative works with their public domain or license status in a machine-readable way. These metadata enable applications to find, for example, photographs that are free to use provided that the original photographer is credited, or songs that may be copied, distributed, or sampled with no restrictions whatsoever. They provide an RDF Schema (http://creativecommons.org/technology/metadata/implement) with two major parts: a work description, and a license description. The work description uses Dublin Core properties to provide information about the work. Finally they provide online tools to generates the metadata describing your resources (http://creativecommons.org/license/)

Usecase:
"Too often the debate over creative control tends to the extremes. At one pole is a vision of total control - a world in which every last use of a work is regulated and in which 'all rights reserved' (and then some) is the norm. At the other end is a vision of anarchy - a world in which creators enjoy a wide range of freedom but are left vulnerable to exploitation. Balance, compromise, and moderation - once the driving forces of a copyright system that valued innovation and protection equally - have become endangered species. Creative Commons is working to revive them. We use private rights to create public goods: creative works set free for certain uses. Like the free software and open-source movements, our ends are cooperative and community-minded, but our means are voluntary and libertarian. We work to offer creators a best-of-both-worlds way to protect their works while encouraging certain uses of them - to declare 'some rights reserved.' "

Author:
Creative Commons non-profit corporation

More information:
Information for creators and developers

Categories Applications and Demos | Licenses and Copyrights | Ontology-based searching | dissemination
Posted by fgandon at 08:43 AM | Comments (0)

January 27, 2004

w3photo image annotation work

As part of SWAD-Europe's dissemination efforts, and continuing on the the theme of Image annotation from the workshop we held in June 2002, we have been collaborating with a number of other groups a project to annotate photos from the WWW series of conferences. Also involved are Greg Elin, who came up with the idea; members of the Mindswap group from Maryland, members of the IAM group from Southampton, and others including Jim Ley, Morten Frederiksen, Masahide Kanzaki and Benjamin Nowack. There is a mailing list, semantic-photolist@unitboy.com, that anyone can join, currently archived at www-archive@w3.org archives), and we have held several IRC meetings on the #rdfig channel on freenode.

From the point of view of the SWAD-Europe project, our interests are:

  • discussing and improving vocabularies for annotating parts of an image
  • experimenting with using several different vocabularies together, for example an image vocabulary with a geographical one, a vocabulary describing people, another describing events.

More information about meetings is on the ESW wiki WWW2004; the specification is at W3PhotoSpec, the vocabularies used are documented at: W3PhotoVocabs.

Categories dissemination

Annotating parts of an image

There are several tools for annotating parts of an image, for example Jim Ley's SVG tool and RDFPic as demonstrated at the SWAD-E image annotation workshop; also Greg Elin's fotonotes, Masahide Kanzaki's javascript image annotator, and a java tool called Photostuff from the Mindswap group.

Discussions on IRC have centred around the requirements for a vocabulary for describing parts of images, which would include

  • simple mapping to SVG and image maps;
  • extensibility to other forms of media later;
  • consistent with being able to describe what a region depicts (compared to what an entire image depicts);
  • ability to assign uris to parts of an image;
  • taking into account vocabularies such as Jim Ley's vocab, Mindswap vocab

An email from Morten Frederiksen outlines the descisions made and the reasons for those decisions. It is hoped that a home for the RDF/OWL vocabulary can be found on the W3C site. Further discussions are likely to occur on the w3photo list and perhaps on a proposed new list

Mixing vocabularies for image annotation

Discussions about mixing vocabularies for image annotation have sometimes occured on the FOAF mailing list as part of the codepiction project and similar efforts by independent programmers. They have often centred around adding geographical information to photos, but also mixing in event information and Dublin Core data, as well as the core 'depicts/depiction' information about who or what is depicted in the photo, using FOAF and Wordnet classes and properties. The w3photo project is also concerned with rights and licensing of the metadata and images for use as sample data for different systems.

Two very interesting issues have come up, at least one of which deserves its own FAQ entry (although at the moment the answer is unlear). The first is:

When you are using terms from another vocabulary, should you use them directly, or create aliases to them using owl:sameClassAs?

This is a very difficult question but I will try to summarise the main points here. Essentially it has to do with technological maturity, processing power, and backwards compatibility. Creating a new OWL ontology with links back to other existing vocabularies means that you get a nice neat description of the vocabulary you want to use, which you can control should the existing vocabularies disappear or redefine their terms. From an OWL point of view, using owl:sameClassAs means there is no difference between using the external classes and properties directly and using the newly defined versions.

However, many tools cannot handle OWL structures; nor even RDFS structures, and so where there is substantial existing data using a pre-existing vocabularies, creating a whole new one reduces interoperability. Even for tools which can handle OWL, extra processing is required to perform the reasoning to link the new terms to the old ones, and so the result of creating a new vocabulary is slower applications. The ESW wiki has a page for notes on this topic.

Supplementary questions include:

  • For a new schema, should I create two schemas (one RDFS, one OWL) for any given vocabulary, or will one do? what would it look like? should it be OWL DL, or OWL Full (or OWL Lite?)
  • How can I describe somewhere the links between existing schemas that I'm making if I don't use owl:sameClassAs or reciprocal rdfs:subClassOf? and relatedly, the second main question:
How can you validate RDF for a particular tool to use?

RDF is not generally concerned with document-level validation, but nevertheless it is very useful to have this level of validation in certain cases. In the w3photo project the aim is to have several different applications which create RDF describing photos, and several different applications which will consume it for display, and document-level validation will be useful for this.

At the document level, decisions need to be made about the minimal set of properties and classes needed so that the consumers can display what is produced: if a consumer can expect that a typical document has no required parts, the effort expended in API calls or queries will be expensive.

Another reason for using document-level validation is the need for 'referential integrity', or at least the hope that at least some references - to people, events - will be consistent between annotations. If I state that this is a picture of 'Bob Smith', that's not a good identifier for the Bob I'm talking about, even within the limited context of the attendees of the WWW2003 Web Conference. If I state that this picture was taken at the conference with the name 'WWW2003', that might normally disambiguate it, but in some circumstances may not (for example there were two conferences with the acronym 'ISWC' going on at the same time in 2003). Where URIs are not directly used to identify things in the world (like people), identity reasoning depends on the presence of particular properties. In this case, identification of any references to individuals - people or conferences - needs to be at the document level.

A final reason is that for the purposes of w3photo project, licenses are essential, and these need to be present for both the metadata itself (the descriptions of the people for example), as well as for the image. These don't need to to be in the same document (because they reference an Image and a metadata document both by their URL) but it is useful in a distributed project like this one to do the checking at the document level, so that the use of any particular server to access the collection of data will produce consistent results.

So, how can you validate RDF documents like this?

Perhaps the simplest way (implemented here) is to use a 'Schemarama'-like system - a set of RDF queries mixed with if-then blocks. For example an Image MUST be present, and MUST have a dc:description. Or a foaf:depicts property MAY be present, and if one is found, it MUST have some identifier for the person depicted, either a hashed version of their email address, or their homepage, or something else.

An interesting question is whether it is possible to use OWL to specify these kinds of document-level constratints. We are hoping that this and some of the other questions discussed here can be anwsered in due course.

Posted by lmiller2 at 03:34 PM | Comments (0)