- From: David Booth <david@dbooth.org>
- Date: Sun, 28 Apr 2013 22:30:42 -0400
- To: Bo Ferri <zazi@smiy.org>
- CC: public-rdf-comments@w3.org
On 04/27/2013 05:49 PM, Bo Ferri wrote: > Hi all, > > On 4/24/2013 8:33 PM, David Wood wrote: >> Hi David, >> >> Just so you hear another viewpoint on this topic, I consider any >> reference to Linked Data to be an (indirect) reference to RDF. Linked >> Data explicitly uses the RDF data model. > > I object to this a bit and I think other people out there as well ... ;) > > see also "A generalisation of the Linked Data publishing guideline" [1]. > so the Linked Data definition in the JSON-LD spec is just fine. AFAICT you are proposing that the term "Linked Data" be co-opted and redefined for a different purpose than it was originally intended, as it very clearly was -- and has been for several years -- inextricably linked to RDF (the Semantic Web). I would vehemently disagree with any proposal to change its meaning in such a fundamental way, as doing so would be quite harmful to the Semantic Web community. If you wish to refer to a different, non-RDF, non-Semantic-Web notion of data interconnection, please coin a new term rather than name squatting on an established term that is so important to the Semantic Web community. David Booth > > Cheers, > > > Bo > > > [1] > http://smiy.org/2011/02/17/a-generalisation-of-the-linked-data-publishing-guideline/ > > >> >> (chair hat "off") >> >> Regards, >> Dave >> -- >> http://about.me/david_wood >> >> >> >> On Apr 24, 2013, at 10:52, David Booth <david@dbooth.org> wrote: >> >>> Hi Manu, >>> >>> Thanks for your remarks. I don't agree with all of them, and just >>> for completeness I'll note in-line below which ones and why, but >>> rather than focus on those details I think it would be better to >>> discuss this at a higher level, because you brought up a very >>> interest point about potentially skolemizing blank nodes, and I think >>> that raises the possibility of a different path for addressing the >>> issue that JSON-LD should be an RDF syntax. >>> >>> To my mind, the central problem that needs to be addressed is that, >>> at present, the draft of JSON-LD >>> http://dvcs.w3.org/hg/json-ld/raw-file/default/spec/latest/json-ld/index.html >>> >>> reads as an attempt to divorce Linked Data (and JSON-LD) from RDF. >>> This is evidenced in several places throughout the document. For >>> example, the definition of Linked Data in the introduction fails to >>> mention RDF at all: >>> [[ >>> Linked Data is a technique for creating a network of inter-connected >>> data across different documents and Web sites. In general, Linked >>> Data has four properties: 1) it uses IRIs to name things; 2) it uses >>> HTTP IRIs for those names; 3) the name IRIs, when dereferenced, >>> provide more information about the thing; and 4) the data expresses >>> links to data on other Web sites. >>> ]] >>> >>> I suggest fixing that omission by inserting the words "based on RDF" >>> into the first sentence, to read: "Linked Data is a technique, based >>> on RDF, for creating a network of inter-connected data across >>> different documents and Web sites." >>> >>> The same sentiment of divorcing JSON-LD from RDF is evidenced in >>> other places in the document as well, such as in phrases like >>> "converted to RDF", and in the definition of a JSON-LD data model >>> that is completely separate from the standard RDF data model, >>> complete with parallel terms such a "blank node" and "blank node >>> identifier". Left as is, the world would have parallel and competing >>> standards for Linked Data: those based on JSON-LD and its data model, >>> blank nodes, etc., and those based on RDF and its data model, blank >>> nodes, etc., because JSON-LD is *not* RDF. >>> >>> One might claim that JSON-LD *can* be used as a serialization of RDF, >>> and therefore JSON-LD *is* already based on RDF. But that argument >>> does not hold water, because that same claim can be made of *any* >>> language! *Any* language can be viewed as a serialization of RDF, >>> given an appropriate mapping. Indeed, the whole purpose of GRDDL was >>> to enable such mappings to be easily defined from XML and HTML. Many >>> people have defined mappings from CSV to RDF, and from many other >>> things to RDF. We do not need a JSON syntax that *can* be mapped to >>> RDF. We need a JSON syntax that *is* a standard serialization of >>> RDF, based on the RDF data model and RDF semantics -- not a parallel >>> (but subtly different) data model, terminology and semantics. >>> JSON-LD at present defines a parallel universe that looks confusingly >>> similar to RDF -- even co-opting terms such as "blank node". >>> >>> I am sympathetic to -- and fully support -- the goal of making >>> JSON-LD easy for people to use, **without knowing anything more about >>> RDF than what they learn about JSON-LD,**. But I also think it is >>> critical that JSON-LD still be normatively based on RDF and grounded >>> in the RDF data model and semantics. And I think it is also pretty >>> clear in the charter >>> http://www.w3.org/2012/ldp/charter >>> that the work of the group was intended to be **based on RDF** -- not >>> "inspired by RDF" or "similar to RDF" or "addressing the same goals >>> as RDF". In other words, the LD working group should define a >>> JSON-based "RDF serialization syntax", as the charter calls it. >>> >>> Can the group achieve both of these aims? I think so. And I think >>> one way to achieve it would be to define a normative mapping between >>> the JSON syntax and the RDF abstract syntax, by using skolemization >>> in places where prohibited blank nodes would otherwise appear, such >>> as in the predicate position of an RDF triple. >>> >>> Specific suggestions: >>> >>> 1. Insert "based on RDF" to the definition of Linked Data, as >>> explained above. >>> >>> 2. Define a *normative* bi-directional mapping of a JSON profile to >>> and from the RDF abstract syntax, so that the JSON profile *is* a >>> serialization of RDF, and is fully grounded in the RDF data model and >>> semantics. >>> >>> 3. Use skolemized URIs in the normative mapping to prevent mapping >>> JSON syntax to illegal RDF. >>> >>> 4. Make editorial changes to avoid implying that JSON-LD is not RDF. >>> For example, change "Convert to RDF" to "Convert to Turtle" or >>> perhaps "Convert to RDF Abstract Syntax". >>> >>> 5. Define normative names for, and clearly differentiate between, the >>> JSON serialization of RDF and JSON-LD, such that JSON-LD *is* a JSON >>> serialization of RDF, with additional constraints for Linked Data >>> (such as URIs use "http:" prefix, etc.). They do not necessarily >>> have to be defined in two separate documents. They could be defined >>> in a single document called "JSON-RDF and JSON-LD", for example. >>> People that use the JSON RDF serialization for purposes other than >>> Linked Data need to be able to easily and clearly talk about that >>> serialization *without* wrongly implying adherence to the additional >>> Linked Data requirements imposed by JSON-LD, and *without* having to >>> explain that those requirements can be ignored in this case. >>> >>> If there is one thing we all should have learned from the Semantic >>> Web, it is the value of assigning an unambiguous name to every >>> important concept. A JSON serialization of RDF is a *very* important >>> concept and deserves its own unambiguous name, distinct from JSON-LD. >>> >>> BTW, regarding the name "JSON-RDF", when I first read your response at >>> http://lists.w3.org/Archives/Public/public-rdf-comments/2013Mar/0036.html >>> >>> saying "We couldn't use JSON-RDF because a variation on the name was >>> already taken", I assumed you meant that RDF/JSON was a defunct >>> proposal, and I was going to suggest that if it is defunct, then >>> there would be little harm in noting it as defunct, and using the >>> term "JSON-RDF". But when I view the RDF/JSON document now at >>> https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-json/index.html# >>> I see it is dated "24 April 2013" and it says that is is a product of >>> the RDF working group. So what's going on? Why is the W3C >>> standardizing *two* potential JSON serializations of RDF? How are >>> they related or different? If this is a W3C activity then these >>> activities should be coordinated, *one* should be picked -- that's >>> what standards are for -- and the name JSON-RDF can be used for that >>> one. >>> >>> 6. Some small editorial fixes: >>> >>> "Since JSON-LD is 100% compatible with JSON" would be better phrased >>> as "Since JSON-LD is a restricted form of JSON", because saying that >>> JSON-LD is compatible with JSON wrongly suggests that JSON-LD is >>> *not* JSON, when in fact it is. >>> >>> s/secrete agents/secret agents/ >>> >>> Thanks, >>> David Booth > > > > > >
Received on Monday, 29 April 2013 02:31:15 UTC