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This Week’s Semantic Web

23rd June 2008, 07:14 pm by Danny Ayers In: This Week's Semantic Web 0

Selected links related to Semantic Web technologies for the week ending 2008-06-23, all weeks. Also available in RDF as linked data or via GRDDL (this might not be fully functional right now, we just migrated to WordPress and it may be that not eveything is in place yet).

Only a minimal offering this week, a tiny fraction of the things that have been happening recently, but hopefully better than nothing (just to get back into the saddle - I’m still catching up after several week’s travel/holiday time). If you know of something from the last few weeks that simply must appear, please mail me and I’ll include it next week - Danny

In the Media

Docs

Software News

Events etc.

Miscellany

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Sources include Planet RDF, various other blogs, Semantic Web Interest Group IRC Chatlogs & Scratchpad, ESW Wiki, SemWebCentral, Sweet Tools, W3C Semantic Web Activity, mailing lists, personal emails etc etc. If you see anything suitable this coming week, please mail meor use the del.icio.us tag “TWSW” - thanks!

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First impressions of “Semantic Web for the Working Ontologist”

2nd June 2008, 01:55 pm by Danny Ayers In: Uncategorized 1

Semantic Web for the Working Ontologist

Semantic Web for the Working Ontologist Effective Modeling in RDFS and OWL is a new book authored by Dean Allemang and Jim Hendler. I can offer a quick summary by teasing apart the title. For starters, the Semantic Web it discusses is generally in line with the current consensus view of the developer community, though with a lean in the direction of the ‘O’ word. The emphasis in the book is very much on Working and Modeling. It is practically oriented, and while it covers most of the technologies associated with the Semantic Web, its focus is on how to describe things using RDF, RDFS and OWL.

There’s a serious shortage of approachable books in the Semantic Web space - if you check the ESW Wiki list, there are only a handful that aren’t heavy duty academic works. Aside from the issue of convincing publishers there’s a market for such material (a problem that’s no doubt evaporating), there’s the difficult problem of what to write about. In the 2003 book Practical RDF, Shelley Powers used the parable of the Blind Men and an Elephant to suggest how RDF has many different aspects and can mean different things to different people - and RDF is just one Semantic Web technology (though arguably the most important). What’s more the elephant changes over time and is lavishly decorated: while the core standards solidified in 2004, since then we’ve seen various auxiliary specifications come along: the SPARQL query language, Turtle/N3 syntax, RDFa, GRDDL and so on. Ideas on best practices have also developed considerably over the years. This book is scoped to modeling with RDF, RDFS and OWL, and covers that ground admirably.

Allemang and Hendler are known experts, well-versed in the subject matter, but what’s more they have spent considerable time teaching courses on the Semantic Web, and this experience shows. The writing is clear and the book’s full of well-illustrated examples, along with a short but very handy FAQ at the end. The practical side is hinted at in their decision to devote significant space to the SKOS Simple Knowledge Organization System and FOAF Friend of a Friend vocabularies. The syntax used throughout is N3/Turtle, which makes a refreshing change from the eyestrain of RDF/XML.

There aren’t any programming (as in running code) examples, and the coverage of things like HTTP and the use of these technologies on the Web is really confined to illustrated prose. I must admit I was disappointed by the limited coverage of SPARQL, I do think this has relevance to modeling decisions. Given the rise of Linked Data in the wild, I would also have expected maybe a chapter devoted specifically to this approach (the ideas are all there in the text, but they don’t jump out).

On the other hand the coverage of reasoning with Semantic Web languages is excellent, material that can be very hard to get a handle on is here presented in an easily digestable form. Similarly the fundamental theory is explained in simple terms without recourse to arcane notation, and common misconceptions around the Semantic Web are disposed of without malice.

Contents

  1. What is the Semantic Web?
  2. Semantic Modeling
  3. RDF – the Basis of the Semantic Web
  4. Semantic Web Application Architecture
  5. RDF and Inferencing
  6. RDF Schema Language
  7. RDFS-Plus
  8. Using RDFS-Plus in the Wild
  9. Basic OWL
  10. Counting and Sets in OWL
  11. Using OWL in the Wild
  12. Good and Bad Modeling Practices
  13. OWL Levels and Logic
  14. Conclusions
  15. Frequently Asked Questions

RDFS-Plus is RDFS with the addition of some handy bits of OWL (IFPs etc).

In conclusion, this is an approachable book for anyone with interest in the field, and gives excellent coverage of the Semantic side of the Semantic Web, as it pertains to modeling the real world. With the caveat that this is the scope of this book, I’d personally strongly recommend it. I do intend to read this book cover to cover thoroughly, it is insightful writing, and as an occasional OWL user I’ll be keeping it on hand for the recipes.

See also: Henry’s [p]review

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This Week’s Semantic Web

12th May 2008, 06:40 pm by Danny Ayers In: This Week's Semantic Web 0

Selected links related to Semantic Web technologies for the week ending 2008-05-12, all weeks. Also available in RDF as linked data or via GRDDL.

Another burst of activity this week around the general area of DataPortability, with announcements from MySpace, Facebook and Google regarding the opening up of social network data. While it isn’t yet clear how much better these systems will at meshing with the Giant Global Graph, it certainly seems a step in the right direction.

In the Media

Docs

Software News

Events etc.

Miscellany

Quote of the Week

the semantic web is already here if you know where to look

- Julian Higman

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Sources include Planet RDF, various other blogs, Semantic Web Interest Group IRC Chatlogs & Scratchpad, ESW Wiki, SemWebCentral, Sweet Tools, W3C Semantic Web Activity, mailing lists, personal emails etc etc. If you see anything suitable this coming week, please mail meor use the del.icio.us tag “TWSW” - thanks!

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DataPortability: In-Motion Podcast

10th May 2008, 08:16 pm by Danny Ayers In: Podcast 0

I just had the pleasure of being a guest on DataPortability: In-Motion Podcast - Episode 7. Trent has show notes over there. It’s got quite a bit of discussion about the role of Semantic Web technologies in DataPortability, some argument about the role of microformats (a transitional technology, or an end in themselves?), some stuff on business aspects of the Web (not exactly my forte) a little handwaving about Talis (should have been better prepared for that - but I often forget we’re a commercial entity :-)

Notable quote (not from me, more’s the pity):

Doesn’t matter how big you are, the Web is always bigger

The interview part is preceded by a segment on some legal aspects to DP, along with the news of MySpace and others announcing they are further opening up their systems. The news came after the interview was recorded, in case it seems strange it wasn’t mentioned.

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This Week’s Semantic Web

6th May 2008, 08:08 pm by Danny Ayers In: This Week's Semantic Web 0

Selected links related to Semantic Web technologies for the week ending 2008-05-06, all weeks. Also available in RDF as linked data or via GRDDL.

A little later and shorter than usual this week due to public holiday and rsi…normal service will be resumed next week.

In the Media

Docs

Software News

Events etc.

Miscellany

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Sources include Planet RDF, various other blogs, Semantic Web Interest Group IRC Chatlogs & Scratchpad, ESW Wiki, SemWebCentral, Sweet Tools, W3C Semantic Web Activity, mailing lists, personal emails etc etc. If you see anything suitable this coming week, please mail meor use the del.icio.us tags “semweb weekly” - thanks!

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This Week’s Semantic Web

21st April 2008, 04:29 pm by Danny Ayers In: This Week's Semantic Web 0

Selected links related to Semantic Web technologies for the week ending 2007-04-21, all weeks. Also available in RDF as linked data or via GRDDL.

How the Web Works

- source: danbri on Flickr, CC
license

A fairly random mix this week. Above you can see Dan Brickley’s revision of the imagery that first saw light in Tim Berners-Lee’s slides in 1994. The original slides showed the connection between Web documents and things in the real world. Danbri’s added a nice twist in the thoughts of the people in the diagram - they don’t necessarily see the world in the same way. Fortunately Semantic Web technologies offer ways of saying things which allows for differing perspectives, and means to make use of coincidences between things different people have said. In recent months DBpedia has played a key role in the Linking Open Data cloud by providing common reference points derived from Wikipedia (check the podcast with Richard Cyganiak). This week sees the announcement of a set of new services around UMBEL, an upper-ish ontology which aims to provide a similar role.

There are a few more offerings for further up the Semantic Web stack from the W3C, and to demonstrate that such things aren’t necessarily incompatible with regular RDF development, Jim Hendler points to an OWL 2 profile that should be of interest to even the most web-fetishist audience: Towards RDFS 3.0 (or OWL 2 R Full).

A little trivia: subscribers to Planet RDF (one of the main sources for material here) may have noticed my personal blog hasn’t appeared recently, I’ve still got a few things to fix up after a bad server crash. This blog may not appear over there either for a little while as the Talis blogs are migrated over to being
WordPress-based. So the only conduit from Talis to Planet RDF this week is Ian’s blog, latest offering: The Terrible And Tragic Tale Of Brian The Snail. I suppose there’s always the magazine…

In the Media

Docs

Software News

Events etc.

Miscellany

~

Sources include Planet RDF, various other blogs, Semantic Web Interest Group IRC Chatlogs & Scratchpad, ESW Wiki, SemWebCentral, Sweet Tools, W3C Semantic Web Activity, mailing lists, personal emails etc etc. If you see anything suitable this coming week, please mail meor use the del.icio.us tag “twsw” - thanks!

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