RE: SOSA/SSN integration architecture

I used the term ‘hijacking’ because I believe in the past that has been used for every case of adding axioms to someone else’s class or property. (

But the key idea was that creating a new class in the SSN namespace that is equivalent to a class in the SOSA namespace may not be necessary. (But may only be acceptable where the additional axioms only formalize definitions provided in text in SOSA, or maybe not.)

I think this matches your intention with Option 5.

From: Rob Atkinson [mailto:rob@metalinkage.com.au]
Sent: Sunday, 26 February, 2017 22:48
To: Armin Haller <armin.haller@anu.edu.au>; Maxime Lefrançois <maxime.lefrancois@emse.fr>; Rob Atkinson <rob@metalinkage.com.au>; Raphaël Troncy <raphael.troncy@eurecom.fr>; public-sdw-wg@w3.org
Subject: Re: SOSA/SSN integration architecture


Version I edited has this a 3b/1b - so not sure what else changed since - but in the context of 3a I had read this as ssn "hijacking" sosa meaning adding restrictions that changed its meaning. If the meaning of "hijacking" means just adding axioms already expressed in sosa text then I believe these are the same....

AFAICT the updated 2b/3c version is now identical to Option 5, without the confusing language.

and IMHO much better as a separate option than something bundled in as a sub-option of something otherwise fundamentally different (e.g. the nub of option 2 using subclasses to create proxies in a new namespace)
(the ssn:System superclass came from a different conversation and I believe is the intent here and relevant to the discussion - i think defining a more general class from a core module is a pattern we need to provide guidance about the best practice.



On Sun, 26 Feb 2017, 4:36 PM Armin Haller <armin.haller@anu.edu.au<mailto:armin.haller@anu.edu.au>> wrote:
I agree that hijacking conveys a negative meaning. Raphaël already mentioned earlier that he does not want to convey that negative meaning, so your renaming to “precises” is good.

We could make Option 2b/3c just Option 5. I will wait for Rob’s response, but as it looks to Simon and me, these two options are the same.

From: Maxime Lefrançois <maxime.lefrancois@emse.fr<mailto:maxime.lefrancois@emse.fr>>
Date: Saturday, 25 February 2017 at 12:30 am
To: Rob Atkinson <rob@metalinkage.com.au<mailto:rob@metalinkage.com.au>>, Armin Haller <armin.haller@anu.edu.au<mailto:armin.haller@anu.edu.au>>, Raphaël Troncy <raphael.troncy@eurecom.fr<mailto:raphael.troncy@eurecom.fr>>, "public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>" <public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>>

Subject: Re: SOSA/SSN integration architecture

Dear all,


I checked the options 2 to 4 and corrected some inconsistencies with respect to the URIs of the ontologies. :
 - the URI of the SOSA ontology is once written http://www.w3.org/ns/sosa/, and once written unify:localname. From this one can infer that ''unify'' equals "sosa", and ''localname'' equals the empty string.
 - the URI of the SSN ontology is also written unify:localname, so it has  the  same URI as the SOSA ontology.


The object of the rdfs:isDefinedBy is often the ontology where the term is defined, not the namespace.
I updated the snippets to reflect this. Please tell me if you think otherwise.


I believe term "hijacking" is not well chosen here. It's conveys a negative meaning, and does not reflect what is actually happening:
SSN "refines", or "precises" the semantics of some SOSA terms. I changed hijacking to "precises".


In option 2b/3c, SOSA and SSN are  not in the same namespace, hence I hardly see why it would  be considered  as a variant of option 2.

I just added some spaces in option 5 to correct the "code" sections.

Kind regards,
Maxime

Le ven. 24 févr. 2017 à 09:03, Rob Atkinson <rob@metalinkage.com.au<mailto:rob@metalinkage.com.au>> a écrit :

And the mime type handling is a corner case that only applies to the case of clients who want owl and gind resources that dont use explicit imports - ir instead choose to rely on namespace only (if indeed such clients exist)

On Fri, 24 Feb 2017, 6:36 PM Rob Atkinson <rob@metalinkage.com.au<mailto:rob@metalinkage.com.au>> wrote:

No the difference is no neec to subclass sosa terms to ssn equivalents.

Perhaps this makes no difference after owl entailment but it makes a big difference in that ssn instances are not sosa instances without extra reasoning.

Rob

On Fri, 24 Feb 2017, 4:23 PM Armin Haller <armin.haller@anu.edu.au<mailto:armin.haller@anu.edu.au>> wrote:
Now that you have described your option, I don’t see any difference to Option 3b which itself is a slight variant of Option 2 (reusing of terms ONLY rather than reintroducing terms within the new namespace).

You define terms in SOSA.
In SSN you import these terms and add axioms.
If the term has not been introduced in SOSA, you define it in the new module-specific namespace (SSN).

If I interpret this correctly, it is exactly Option 3b with the addition of the mechanism of handling MIME types.

From: Rob Atkinson <rob@metalinkage.com.au<mailto:rob@metalinkage.com.au>>
Date: Friday, 24 February 2017 at 1:58 pm
To: Rob Atkinson <rob@metalinkage.com.au<mailto:rob@metalinkage.com.au>>, Armin Haller <armin.haller@anu.edu.au<mailto:armin.haller@anu.edu.au>>, Maxime Lefrançois <maxime.lefrancois@emse.fr<mailto:maxime.lefrancois@emse.fr>>, Raphaël Troncy <raphael.troncy@eurecom.fr<mailto:raphael.troncy@eurecom.fr>>, "public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>" <public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>>

Subject: Re: SOSA/SSN integration architecture

Have added option 5 and some clarifications to issue scope (i.e. what does extended mean)
Rob

On Fri, 24 Feb 2017 at 13:13 Rob Atkinson <rob@metalinkage.com.au<mailto:rob@metalinkage.com.au>> wrote:

IMHO My proposal is not an implementation of option 1,  because new terms in SSN are added to a new namespace, and only axioms 100% compatible to SOSA are allowed in SSN against SOSA defined terms.

Option 1 seems to be explicitly about the opposite strategy: new terms in SSN in the SOSA namespace and heroics in the infrastructure to manage finding these.

I'm convinced its different, and simpler than the existing options and will add it - we can always remove it if people can prove one of the other cases is equivalent,

Rob




On Fri, 24 Feb 2017 at 10:38 Armin Haller <armin.haller@anu.edu.au<mailto:armin.haller@anu.edu.au>> wrote:
Thanks!

I have removed the *bold* in the implication of Option 1. I do want to keep the implications neutral. Some people may care a lot about that specific implication, some others not.

I also deleted the statement “always the case with slash-based URIs” with the “One needs to dereference a term to figure out where this term is defined”. Raphaël added the yesterday as an implication. The commonly expected behaviour/expectation with Ontology Slash URIs on the Linked Data Web is that the ontology sits at the directory level of that term. I think it is a valid point to make in this option that the behaviour here and in Option 2 would be different. Again, some people may care about that, some others not.

From: Maxime Lefrançois <maxime.lefrancois@emse.fr<mailto:maxime.lefrancois@emse.fr>>
Date: Friday, 24 February 2017 at 6:09 am
To: Raphaël Troncy <raphael.troncy@eurecom.fr<mailto:raphael.troncy@eurecom.fr>>, Armin Haller <armin.haller@anu.edu.au<mailto:armin.haller@anu.edu.au>>, "public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>" <public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>>

Subject: Re: SOSA/SSN integration architecture

Dear all,

I updated option 1, and highlighted its multiple variants,

I would like to highlight variant sosa1, for which looking up the unified namespace leads to the SOSA ontology.

Kind regards,
Maxime


Le jeu. 23 févr. 2017 à 12:12, Raphaël Troncy <raphael.troncy@eurecom.fr<mailto:raphael.troncy@eurecom.fr>> a écrit :
> ➢ Done, changed it on the Wiki. I think that makes it clearer.

Thanks.

> ➢ You can use the ontology URI to figure out which terms are in the core (SOSA). It is the same behaviour as in Option 1. In Option 1 you also either need to dereference each term to figure out where it is defined or to use the ontology URI of SOSA or SSN explicitly. If you think this is an important caveat, you can spell that out in the implication for both options.

I agree, this is true for both options 1 and 2. Done, I have added for
each: "* One needs to dereference a term to figure out where this term
is defined OR to use the ontology URI of SOSA or SSN explicitly since
there is just ONE unify namespace."

Note: Option 3b is still Option 3b and not a variant of Option 1
although it could be.

   Raphaël

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