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Re: On LDOM

From: Holger Knublauch <holger@topquadrant.com>
Date: Thu, 29 Jan 2015 08:49:40 +1000
Message-ID: <54C96784.3010000@topquadrant.com>
To: public-data-shapes-wg@w3.org
Hi Karen,

it is obvious from reading the various emails that I need to do a better 
job explaining what LDOM really is. It is all too easy to draw false 
conclusions. I can write down the same train of thoughts over and over 
again, yet they don't seem to "click". Maybe it is because emails and 
text documents are just not the right medium. I'd be more than happy to 
talk to any WG member on the phone if that helps (just contact me 
off-list). In the absence of better communication channels, let me try 
to respond to your specific concerns here.

On 1/29/2015 5:07, Karen Coyle wrote:
> I see. I was reading it as a model for managing and validating RDF or 
> OWL information in private/closed data stores. In fact, it seems to 
> eschew any contact with the web, 

Why do you believe that a language called "Linked Data Object Model" 
eschews any contact with the Web. As written in the first sentence of 
the Primer

"LDOM (Linked Data Object Model) is an RDF-based modeling language that 
is compatible with Linked Data principles and leverages some 
object-oriented concepts to the Web."

LDOM works very well on both closed and open networks. Class, shape and 
property definitions as well as templates and functions can be looked up 
from the web using the normal RDF resolution mechanisms. It is 
extensible - people can reuse each other's data models across web sites 
and applications. It has exactly the same characteristics that RDFS and 
OWL have, only that it uses the Closed World assumption, and this is 
exactly what the WG was chartered to deliver.

> and treats the semantic aspects of RDF/OWL as (and I quote Holger) 
> "pie in the sky." 

You are quoting me out of context. I never said this about the semantic 
aspects of RDF/OWL. I said this about the idea of mixing together all 
triples in the world in an uncontrolled setting. That vision is of 
course completely unrealistic, because anyone could insert a single 
triple that basically invalidates all other statements. This isn't a 
stable architecture that anyone in practice would use, unless perhaps 
for browsing applications where a human is always in the loop.

> I'm still trying to understand if RDF data intended for the web will 
> fit into its processing model, and again if local data that can be 
> managed by it could also have a web presence without great modification.

Yes. LDOM can obviously be used in closed scenarios. In open scenarios 
it can, for example, be used to publish reusable ontologies that other 
applications and ontologies can reuse. Publishing an LDOM file on the 
Web then means that anyone who wants to reuse the terms from that file 
*should* adhere to the attached semantics. This is exactly like RDFS/OWL 
also do it. If someone just wants to publish a vocabulary without such 
constraints, they can already do that by creating RDFS classes with 
comments, and put the constraints into comments and documentation (as 
done, for example, for SKOS, RDF Data Cube and PROV). LDOM just makes 
those implicit assumptions explicit, for applications that want to 
ensure better integrity of their data. It is therefore a completely 
incremental improvement over existing practices and standards. People 
who prefer to leave their data model open don't need to use LDOM at all.

> I personally was hoping for a solution that is more compatible with 
> RDF data on the web. 

What is missing, where is LDOM not compatible with RDF data on the web?

Thanks,
Holger
Received on Wednesday, 28 January 2015 22:50:14 UTC

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