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

On 7/25/14 12:30 PM, Dan Brickley wrote:
> On 25 July 2014 04:48, Pat Hayes<phayes@ihmc.us>  wrote:
>> >
>> >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 tohttp://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.
> Beyond those findings in "Everything You Always Wanted to Know About
> Blank Nodes", we can add 6M+ internet domains publishing billions of
> entity descriptions using schema.org, an RDF vocabulary. The vast
> majority of this data shows up as bnodes in RDF. There are a few
> tricks for data merging such as ahttp://schema.org/sameAs  property
> which points to indicative documents, e.g. see
> https://support.google.com/webmasters/answer/4620133?hl=en  rather than
> trying to have the http-range-14 conversation with mainstream
> webmasters.
>
> The Linked Data thing began as TimBL expressing a concern that FOAF
> data was needlessly bnodey - hence
> http://www.w3.org/DesignIssues/LinkedData  - and I think we're finally
> settling into a kind of scruffy and pragmatic consensus that both
> styles of graph have a role. High quality professionally published
> Linked Data may lean more towards "well known URIs for all entities in
> the graph", whereas mainstream markup will often use a bnode
> formulation instead. Taking the Music Artists example from my google
> link above, the JSON-LD schema.org triples tell you something like
> this (subsetting for brevity):
>
> A "MusicEvent" with "name" "B.B. King with Jonathon 'Boogie' Long" has
> a "location" (which is a "Place" with "name" "Lupo's Heartbreak
> Hotel"). That "Place" has an "address" that is a "PostalAddress",
> which has such-and-so streetAddress, postalCode etc. The "MusicEvent"
> has a "performer" that is a "MusicGroup". The "name" of that
> "MusicGroup" is "Jonathon 'Boogie' Long". This same "MusicEvent" has
> an "eventStatus" of "EventRescheduled", and a  "previousStartDate" of
> "2013-09-30T19:30".
>
> This seems to me (and to numerous publishers) to be reasonably
> actionable and interpretable information, particularly since it is
> also linked to well known Wikipedia and homepage URLs.
>
> My preference is that we all stop trying to tell publishers how
> exactly to manage their sites and databases, and deal with the fact
> that they'll often have partial information without nice well known
> URIs everywhere.
>
> Dan
>
>
Dan,

I agree with most of what you've outlined above, but there are two 
points of concern, bearing in my preoccupation with RDF and Linked Data 
narrative clarity as a mechanism for quelling a lot of the confusion 
that ultimately introduces roadblocks to RDF comprehension, 
appreciation, and adoption:

1. Linked Data isn't about FOAF and bnodes, TimBL simply used FOAF 
(which was a significant RDF collective) as an anecdote -- HTTP URIs 
have always been instruments of denotation in regards to the World Wide Web

2. Use of schema:sameAs to solve a problem that requires a touch the 
kind of wisdom outlined in the "Judgement of Solomon" story -- we want 
to bridge the requirements of structured data, open data, linked open 
data, and the semantic web, and I don't sense that in schema:sameAs when 
schema:id, schema:denotedBy, schema:identifiedBy, and 
*schema:manyOtherLessProblematicHumanFirstOrientedRealtions* would 
achieve the goal without ruffling the feathers of any of the 
aforementioned audience profiles.

We need to build bridges. Appeasing one community at the expense of the 
other doesn't achieve that goal. We can fix this problem, in a less 
problematic way i.e., nobody has to lose out or be ticked off en route 
to a workable solution.

Links:

[1] http://bit.ly/10Y9FL1 -- Linked Data and the Original World Wide Web 
proposal
[2] http://bit.ly/WAJGCp -- HTTP URI based Entity Denotation in a Single 
Slide
[4] http://bit.ly/get-yourself-a-uri -- post about HTTP URIs that denote 
Agents (where FOAF is used to demonstrate why)
[5] http://en.wikipedia.org/wiki/Judgment_of_Solomon -- Judgement of 
Solomon .



-- 
Regards,

Kingsley Idehen 
Founder & CEO
OpenLink Software
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