Re: Converting RDF to JSON-LD : shared lists between graphs

On Jul 23, 2014, at 2:21 PM, David Booth <david@dbooth.org> wrote:

> Hi Kingsley,
> 
> On 07/23/2014 10:13 AM, Kingsley Idehen wrote:
>> On 7/23/14 6:46 AM, Dan Brickley wrote:
>>>> How so?  It seems to me that there is an inherent tension between
>>>> being nice
>>>> >to RDF consumers (by using URIs for things that other might want to
>>>> refer
>>>> >to, as AWWW recommends) and author convenience, which leads to bnode
>>>> use.
>>> Yes, that's a real tension, although bnodes are just one aspect. My
>>> point was to question the "clearly" in  "the use of blank nodes
>>> clearly violates the web architectural good practice that anything of
>>> importance should be given a URI". Using bnodes is consistent with the
>>> things the bnodes represent having URIs, so nothing is violated. The
>>> reason btw we renamed them "bnodes" instead of the earlier (1997-2000
>>> e.g.http://www.w3.org/2000/03/rdf-tracking/#rdfms-identity-anon-resources)
>>> 
>>> phrase "anonymous nodes" was this point: the things are not anonymous
>>> / nameless. Only particular descriptions of them.
>>> 
>> 
>> +1
>> 
>> Using pronouns (from natural language) to explain the nature of blank
>> nodes helps a lot.
> 
> Maybe, but pronouns are used *very* differently than blank nodes, so it really isn't an accurate comparison.  Normally when a pronoun is used, the corresponding noun is *also* used, so the reader can easily determine the intended noun.  ("When *Jack* got to the bank, *he* stopped.")  But that is not usually the case with blank nodes.  Usually if a blank node is used in an RDF document, no equivalent URI is given for that node.  But still, I can see how the analogy could help sometimes.

The correct analogy is with indefinite pronouns like "someone" or "something". But many uses of blank nodes are in fact more like indefinite noun phrases, eg a bnode with an rdf:type link to http://dbpedia.org/ontology/tree is almost an exact rendering of the English phrase "a tree". 

BTW, recent work crawling the actual existing semantic web shows that about 40% of deployed RDF uses blank nodes. So apparently this "confusing" aspect of RDF is not confusing to a fair number of users. IMO all this noise about 'good' vs. 'bad' RDF is just that, noise. Actual users of RDF, as opposed to writers of technical blogs, seem to be able to handle RDF quite well.

>> 
>> Over the years there's been a tendency to tag vital aspects of RDF as
>> bad, for a variety of reasons that always boil down to assuming that
>> users (end-users and developers) can't figure this stuff out.
> 
> I think we have quite a lot of experience indicating that that is the case.  Even though the basic idea of triples representing simple assertions is easy -- and David Wood has a really nice Dr Seuss-inspired introduction
> http://www.slideshare.net/3roundstones/rdf-explained-by-suess-and-me
> -- RDF also has subtleties that cause complexity and grief in practice and IMO inhibit adoption.  Blank nodes are prime culprits here.  

Do you have any actual evidence for this claim, David? I have never seen any. Most of the noise about blank nodes seems to have been generated by people who dislike them and write a lot. People who understand them and use them easily seem to just get on with the job and don't write spleenish complaints about them.

> And my main argument in this paper
> http://dbooth.org/2013/well-behaved-rdf/Booth-well-behaved-rdf.pdf
> is that if we constrain how blank nodes are used, by eliminating explicit blank nodes while retaining implicit blank nodes, we can simplify RDF usage while retaining the main benefits of blank nodes -- getting the best of both.
> 
>> In my
>> experience, a little flexibility on the narrative and anecdotes front
>> can leads to clarity, appreciation, and adoption.
> 
> Yes, that definitely helps too.  And I appreciate all the work you have done over the years to ease that path.  But I still think RDF is harder than it should be, because of these complexities, and we would gain more adoption if we made it simpler.

"We" are not going to change it at all in the forseeable future, after getting RDF 1.1 done. Writing papers recommending that people stop using it properly according to its specs, the way that it is already being used, do not achieve anything very positive, IMO.

Pat


> 
> David
> 
>> 
>> Here are two important aspects of RDF that typically end up being
>> labeled as problematic:
>> 
>> [1] blank nodes -- pronouns
>> [2] statement reification -- statements are things too!
>> 
>> The items above enable important bridging across:
>> 
>> 1. Open Data -- basic structured data
>> 2. Linked Open Data -- structured data constructed using Linked (Open)
>> Data principles
>> 3. Semantically enhanced Linked Open Data -- structured data constructed
>> using RDFS, OWL, etc., in conjunction with Linked Open Data principles.
>> 
>> 
>> In most cases, rather than reification, RDF user agents will leverage
>> blank nodes as objects of relations that associate embedded structured
>> data with their container documents.
>> 
>> Example:
>> 
>> [1]
>> http://linkeddata.uriburner.com/about/id/entity/http/thenextweb.com/apple/2014/07/23/apple-release-information-ios-response-claims-backdoor-data-collection/
>> -- Statements are reified en route to creating an RDF based Linked Data
>> document that's close to self-explanatory re. follow-your-nose pattern
>> 
>> [2] http://bit.ly/rdf-statement-reficiation-fyn  -- alternative view for
>> deeper follow-your-nose exploration
>> 
>> [3] https://twitter.com/thalhamm/status/471994633573380096 -- tweet
>> about blank node use that's also a segue to a usecase demo.

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Received on Friday, 25 July 2014 03:49:25 UTC