On 6/20/13 2:16 PM, Stephane Fellah wrote:
Kingsley,On Thu, Jun 20, 2013 at 1:28 PM, Kingsley Idehen <[email protected] <mailto:[email protected]>> wrote:On 6/20/13 12:50 PM, Stephane Fellah wrote:Hi, I agree with Luca's viewpoint. The W3C standard RDF model (a.k.a triple model) is one of most fundamental piece of the technology stack defining Linked Data (along with URIs and HTTP).I am not disputing that point. Here's what in dispute, and the topic of debate to me: the misconception that you MUST know anything about RDF en route to creating and publishing Linked Data. RDF is an optional implementation detail with a particular outcome in mind i.e., the ability for humans and machines to understand the entity relationship semantics that constitute the Linked Data.Can you provide some examples to clarify your point here? Do you consider CSV files as Linked Data ?
Of course you can produce Linked Data content via a CSV file [1][2].
Do you consider RDBMS Tables ( using primary keys of the database as identifiers) as Linked data ?
Nice that you asked, I can use RDBMS keys to demonstrate different kinds of Linked Data to you, for sure [3][4][5][6].
Do you consider XML documents using XPointer and XLink as Linked Data (like in Geographic Markup Language GML) ?
By now, you should understand that non of these formats have anything to do with RDF.
Do you consider XML documents using local identifier xml:id as Linked Data ? I personally do not consider them as Linked Data because they do not adhere to the RDF model (meaning I cannot harvest them as a set of triples using URIs). If you disagree with my point, then we should have different terminologies to distinguish RDF compliant data versus the rest.
Circa. 2013, RDF isn't bound to any data serialization format (it never really was).
RDF isn't bound to any concrete syntax for graphical expression of structured data. It has an abstract syntax that outlines the grammar to be used when representing entity relationships using triples (or 3-tuples).
The greatest feature of RDF is that it is self-describing, described, and understandable by an RDF processor sucking in RDF's own vocabulary [7].
I think it is important to make understand the community that Linked Data can be serialized into different representations (Turtle, RDF/XML, JSON-LD, N3, NTriples, TrigG, and any future formats) , as long as they are isomorphic to RDF model (meaning data can be converted to a set of triples and identifiers are based on URIs).I really don't believe that I am disputing this point. Neither do I believe the point (above) is new to anyone on this list.If the data are NOT convertible to RDF model, I do not consider it as Linked Data.And that assertion is inaccurate. It is also indefensible. The World Wide Web as it already exists is full of Linked Data for which RDF processors may or may not exist. It functions, humans and programs understand the "LinksTo" relation etc.. That's why it works and scales the way it does.That is where I differ with you: The World Wide Web as it already exists is full of "Data", not "Linked Data".
Well, we just disagree. I don't know what you think HTML represents, or why you feel documents aren't entities worthy of ambiguous denotation or structured-machine-readable description etc.
In my eyes, the World Wide Web is just medium with evolving resolution. As it evolves the resolution of its constituency (its webby entity relations) simply increases. RDF simply provides a way for us (via RDF processors) to increase the resolution of web-like structured data (which includes the mesh we know as the World Wide Web).
To become Linked Data they need to be converted to RDF Model, meaning be compliant with triple model and uses URIs and HTTP to be linkable.
"RDF Model" doesn't become meaningful by will. You sentence about doesn't mention a single defining characteristic of RDF. Doesn't HTML leverage HTTP and URIs?
CSV files, XML with local identifier files, Database tables are NOT linked data until they adhere to the Triple Model and uses URI for identification (thus being compliant with the RDF Model).
You make Linked Data by making a commitment to the following during the act of creating and publishing web-like structured data:
1. dereferencable URIs as the denotation mechanism for entities being described 2. a data model (basic entity relationship graph *OR* enhanced RDF variant) for structured data representation 3. actual document content comprised of statements that represent entity relationships (and if using RDF said relationship semantics become *explicit* rather than *implicit*).
Guess what, even though the World Wide Web is dominated by HTML content, it was bootstrapped on the back of a draconian mandate that everything MUST be interpretable as HTML. Ironically, DBpedia most powerful deliverable was the use of HTML to expose the concept of Linked Data. We stuck RDF/XML and other formats in the footer pages of said documents.To make the system works, you need some set of standards on which everyone agree: HTTP, URIs, RDF are fundamental to Linked Data.URIs and web-liked structured data representation are fundamental to Linked Data. RDF is fundamental to Blogic.RDF is fundamental to build the "Global Linked Data Graph" (Directed Labeled Graph model based on URIs). Inferencing, ontologies, SPARQL, BLogic, are just value-adds capabilities on top of Linked Data. You do not need BLogic for Linked Data.
If you didn't need Blogic, then why bother giving entities unambiguous names. Why bother having such a concept? Why bother with relationship roles like Subject, Predicate, and Object? I mean, we can just rely on the mysterious magic of the literals "RDF" and poof! All is understood, on this Giant Global (entity relationship) Graph of Linked Data, by humans and machines.
Saying we do not need RDF model for Linked Data is like saying we do not need URL or HTTP for the web of documents.Again, here is what I am saying: You don't need to know anything about RDF to create and publish Linked Data. Please read my words, don't react to them. Based on my comments, I disagree with you on this point.
Clearly you do, but at some point, you will realize what I am trying to unveil here. By the way, I wasn't born with a *unique* understanding of these matters, I came to understand data representation, access, integration, and management over many years of learning from others, across many scenarios and projects.
In my world, every day is a new opportunity to discover and learn something new. I am only afraid of the day when that doesn't happen!
Links:1. http://lists.w3.org/Archives/Public/public-lod/2013Jun/0083.html -- post that started this thread (note: it includes links to a CSV Browser)
2. http://bit.ly/18axeTP -- CSV Browser link that handles SPARQL-FED query results returned in CSV format
3. http://bit.ly/18pGTFd -- green links demonstrating Linked Data in a SQL RDBMS silo (a silo because the URNs derived from the DBMS keys only resolve to relational tables based entity descriptions, locally i.e., I can't copy and paste the URIs to an application outside the DBMS e.g. a Web Browser)
4. http://bit.ly/11Brjz7 -- a Relation based on an relational table remapped to an entity relationship model (e.g., EAV) this is deliberately presented as quad so that the sources Tables aid understand of the context flip
5. http://bit.ly/13fnIbr -- introducing blue links, HTTP URIs replacing those DBMS specific URNs with local scope i.e., Web-scale super keys that resolve to descriptions from anywhere via copy and past
6. http://demo.openlinksw.com/OracleHR/employees/EMPLOYEE_ID/101#this -- example of a Linked Data URI that you can click on en route to seeing HTTP URI de-silo-fication in action combined with Linked Data (RDF magic comes later when I seek to merge disparate data across heterogeneous data sources)
7. http://bit.ly/147HINl -- RDF described in RDF and presented using a Linked Data Browser page
8. http://dbpedia.org/resource/Linked_data -- go to the page footer to see the variety of support formats (btw -- RDF appears to be missing from the abstract, at this point in time)
9. http://bit.ly/15ZxzHo -- Vapor (Linked Data principles conformance verifier) report for the DBpedia URI above (also demonstrating the role formats play in this realm distinct from abstract syntax) .
Kingsley
KingsleySincerely Stephane FellahStephaneOn Thu, Jun 20, 2013 at 11:45 AM, Luca Matteis <[email protected] <mailto:[email protected]>> wrote: On Thu, Jun 20, 2013 at 5:02 PM, Melvin Carvalho <[email protected] <mailto:[email protected]>> wrote: # Restate/reflect ideas that in other posts that are troubling/puzzling and ask for confirmation or clarification. I am simply confused with the idea brought forward by Kingsley that RDF is *not* part of the definition of Linked Data. The evidence shows the contrary: the top sites that define Linked Data, such as Wikipedia, Linkeddata.org and Tim-BL's meme specifically mention RDF, for example: "It builds upon standard Web technologies such as HTTP, RDF and URIs" - http://en.wikipedia.org/wiki/Linked_data "connecting pieces of data, information, and knowledge on the Semantic Web using URIs and RDF." - http://linkeddata.org/ This is *the only thing* that I'm discussing here. Nothing else. The current *definition* of Linked Data. # Restate the actual subject and focus of the discussion; the subject line just doesn’t always cut it. Again the subject line is the *definition* of the term Linked Data. More specifically whether it includes (or should include) RDF. # Do more explication with the awareness that we might be talking about two (or more!) related but separate ideas/concepts. Or we could be using the same terms but with slightly different definitions. I want to concentrate on the current definition of the Linked Data term. Why do the main sites built from the Linked Data community *strictly* describe RDF as one of the main technologies that enable Linked Data? # Define the terms inline rather than just linking out. One’s interpretation of an external standard or specification could be different from someone else’s, so I think it would be good to own it. I simply think RDF is part of Linked Data's definition, because of the evidence I have shown above. If this is not the case, we should discuss it as a community. If we decide that RDF is *not* part of the definition of Linked Data, we should probably remove it from all the top sites, otherwise it will create confusion for newcomers. Also we should make new Linked Data coffee mugs ;-) Luca--Regards, Kingsley Idehen Founder & CEO OpenLink Software Company Web:http://www.openlinksw.com Personal Weblog:http://www.openlinksw.com/blog/~kidehen <http://www.openlinksw.com/blog/%7Ekidehen> Twitter/Identi.ca handle: @kidehen Google+ Profile:https://plus.google.com/112399767740508618350/about LinkedIn Profile:http://www.linkedin.com/in/kidehen
-- Regards, Kingsley Idehen Founder & CEO OpenLink Software Company Web: http://www.openlinksw.com Personal Weblog: http://www.openlinksw.com/blog/~kidehen Twitter/Identi.ca handle: @kidehen Google+ Profile: https://plus.google.com/112399767740508618350/about LinkedIn Profile: http://www.linkedin.com/in/kidehen
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