Don't feed the semantic black holes

If I remember correctly it was at Knowledge Technologies 2001. Ann Wrightson explained us, during the informal RDF-Topic Maps session, how to build a semantic virus for Topic Maps, through abuse of subject indicator. At the time OWL and its now infamous owl:sameAs were not yet around, but the idea was identical : if several "topics" A, B, C, ... indicate the same "subject" X, then they should be merged into a single topic. In linked data land ten years after it's the same story : if RDF descriptions A, B, C ... declare a owl:sameAs link to X, then A and B are merged together with the current description of X.

FRBR in LOV : A Vocabulary is a Work

Along with the migration of LOV to OKFN, as announced in the previous post and now on the OKFN blog, we introduced the version history of vocabularies. The first obvious aspect is a cool visualization, see for example the Geonames Ontology History complete with timeline and links to downloadable versions when available. What's under the hood? It's FRBR all the way down.

LOV moves to OKFN

The LOV story enters a new area today. Pierre-Yves and myself are pleased to announce that the Linked Open Vocabularies (LOV) project is now hosted at OKFN. Many thanks to the Open Knowledge Foundation team which provides the technical support which will help to ensure a sustainable future for this project and the Vocabulary Commons at large.

Pierre-Yves has done a tremendous technical work, not only to ensure a smooth migration from former Mondeca Labs hosting, but also to add a new vocabulary versions and history feature. See for example Dublin Core or SKOS. Versions are displayed on a timeline and the version files and change notes are available as long as we could put our hands on them. Thanks also to all creators and publishers who helped us to sort out the history of their vocabularies. This is far from done for all vocabularies, but we hope the examples already there will push other publishers to make this history available. 

schema.org Tree and the Vocabulary Forest

My feelings about schema.org from the very beginning have been so mixed that I read a lot about it and wrote nothing, until a while ago at the end of the first of LOV stories. Following Dan Brickley's introduction of schema.org to BBC about two weeks ago, Phil Archer is wondering if we should follow Danbri, which means move towards enthusiastic adoption of schema.org as the first general vocabulary of the Semantic Web, covering 50% of our needs, and calling more specific vocabularies long tail for more specialized use. I am more keen to follow Kerstin Forsberg's cautious approach, and started to wonder aloud about it on Google+, attracting a quick answer from Danbri. A sensible and pragmatic one (as usual) but which did not completely convince me to follow him (at least not in the sense proposed by Phil Archer).

LOV stories, Part 3: Vocabularies as Heritage

In previous posts we introduced the Vocabulary Commons, following some of its Gardeners. Let's now  try to imagine how they can turn into a sustainable and resilient ecosystem. In the current state of affairs they look more like a young forest pionneering a new land. A lot of opportunist species have invaded the landscape, some are conspicuous and seem here to stay, some look like they have no future, others have set up in small niches, all kind of interactions and dependencies have emerged.

Should we let the invisible hand of natural selection operate, and let the fittest survive? Do we want those commons to become a wild messy jungle, or rather a pleasant, useful and sustainable garden that we, our children and their children will enjoy? It's certainly how to achieve the latter the DCMI Vocabulary Management Community group has in mind. This group will hold its kick-off meeting on the first day of the London Seminar : Five Years On at the end of this month.

Beyond httpRange-14 addiction

After years of armed peace we get another round of this old debate. Everybody says it's enough and they don't want to hear about it any more but nobody can resist the temptation to jump in once again. Trying to follow the various running threads about it, with cross-postings and forkings is a pain. Nevertheless I added my pinch of salt yesterday, without much feedback so far, except from Mike Bergman who in a personal answer suggests I should turn this into (yet another) formal change proposal. Suggestion much appreciated, coming from a man with one of the deepest understanding of the issue, and thinking along lines similar to the ones developed here for years. That said,  not sure I want to add to the noise, and not sure such a proposal would gain much traction. Moreover the deadline of the call for proposals is now pretty close (only two days). And actually what I have in mind currently would not amend the current "httpRange-14 resolution", but proposes a radical move to escape the non-issues net in which it is entangled.

LOV stories, Part 2 : Gardeners and Gatekeepers

In the previous post, we have seen why Linked Open Vocabularies should be managed following the principles and rules of the commons : shared resources in which each stakeholder has an equal interest. 

Which means that in theory at least, all stakeholders of the commons should be both users and gardeners. In the vocabularies commons the stakeholders (and hence potential gardeners) are as various as can be, actually they encompass all the actual or potential providers, curators or users of linked data, since there is no quality linked data without quality linked vocabularies, as we have explained in a recent post. But let's look at who are the actual current gardeners of the vocabulary commons.

LOV stories, Part 1 : The Commons

It's now been about one year of work with my colleague Pierre-Yves Vandenbussche on the Linked Open Vocabularies (LOV) project. I've already mentioned it lately here on this blog and in various conversations on Google+. This is the first on a series of posts where I will elaborate a little more about the general vision and philosophy of this project, lessons learned so far, and explore possible roadmap towards its sustainable future. 

The philosophy of LOV in a nutshell is the Philosophy of the Commons.

On usage of empty fridges

It's been a while since we've not revisited here our favourite Tao Te Ching chapter, the one from which the title of this blog is derived. Yesterday I found it was a mandatory answer to Danny Ayers' post on Google+, quoting a quite old (2003) but still relevant post by Dan Brickley "Missing is not broken". Worth re-reading indeed, as well as Danny's comment : an empty fridge is still a fridge. And even more useful so according to 老子. The usage of a fridge is allowed by this very emptiness. Whoever came back once from the supermarket to find the fridge already full has understood that a full fridge is useless until you start to empty it. Granted, by Laozi times, fridges and supermarkets were barely concepts, but useful empty clay pots did the trick.

Protagoras and foaf:Person

πάντων χρημάτων μέτρον έστιν άνθρωπος,
των μεν όντων ως έστιν,
των δε ουκ όντων ως ουκ εστίν

About 2,500 years later, does the famous Protagoras aphorism still apply to things (χρήματα) in the Linked Data universe? The usual translation "Man is the measure of all things" could be misleading when put in parallel with the RDF motto "Everything is a Thing". The ancient Greek χρήμα has actually a more restrictive and pragmatic meaning, namely those things that one actually either holds and uses or badly needs, hence goods, possessions, money. And with this meaning in mind, the Protagoras aphorism is much less mysterious. Man(kind) is or should be the measure of what is needed and useful to mankind, either what one holds (things which are) or what one lacks (things which are not).

In the Linked Data universe, if everything is a thing, not everything is used or even useful.

Is your linked data vocabulary 5-star?

You have created and published on the Web linked data following the best practices and you think they are now 5-star data. But are the vocabularies, RDFS or OWL classes and properties your dataset is using, also 5-star? At the above link one can read some kind of wishful thinking expressed by Tim Berners-Lee:

The third rule, that one should serve information on the web against a URI, is, in 2006, well followed for most ontologies … One can, in general, look up the properties and classes one finds in data, and get information from the RDF, RDFS, and OWL ontologies including the relationships between the terms in the ontology. 

Unfortunately, even in 2012, this is yet far from being true in general.