Re: My best practices for Ontology versioning for http://nlp2rdf.org, was Re: Versioning system for ontologies

On Tue, Apr 23, 2013 at 5:38 PM, Jonathan A Rees <rees@mumble.net> wrote:

>
>
> On Mon, Apr 22, 2013 at 6:17 AM, Daniel Garijo <dgarijo@fi.upm.es> wrote:
>
>> Hi, I'm not sure I see the issue here.
>>
>>
>> 2013/4/22 Sebastian Hellmann <hellmann@informatik.uni-leipzig.de>
>>
>>>  Hm, no actually, this issue is quite easy, when it comes to large
>>> databases.
>>>
>>> curl -H "Accept: text/turtle"
>>> "http://dbpedia.org/ontology#PopulatedPlace"<http://dbpedia.org/ontology#PopulatedPlace>
>>> is pretty much the same as:
>>> curl -H "Accept: text/turtle" "http://dbpedia.org/ontology"<http://dbpedia.org/ontology>
>>>
>>
> Wrong comparison, what you would want is
>
>  "http://dbpedia.org/ontology/PopulatedPlace#class"<http://dbpedia.org/ontology>
>
> or #it or #_ or whatever you like.
>
> So hash URIs work just fine even in large namespaces, you just take what
> would have been the / URI were you to choose the bizarre / URI pattern, and
> append a fragid to it. Basically there is no reason to ever use non-# URIs
> in RDF other than aesthetics (which is irrelevant in contexts mainly meant
> for machine consumption) and when naming documents that are on the web and
> don't have a metadata page.
>

Maybe I get this wrong but I think that your suggestion is for aesthetics
reasons only.
What is the usefulness in this case? I see only a redundant fragment

PREFIX option1: <http://dbpedia.org/ontology/>
use: option1:PopulatedPlace#class % I am not sure if this is valid in all
rdf serializations / sparql

PREFIX option2: <http://dbpedia.org/ontology/PopulatedPlace#>
use: option2:class  % prefix becomes useless

ok, maybe in just RDF it could make sense but we are also talking about
Linked Data here.
The consuming machine can be a mobile or a sensor and downloading the whole
ontology instead of a small fragment may hurt both bandwidth and battery

Best,
Dimitris


>
> Jonathan
>
>
>>
>>> But here you are not asking for any instance. You are asking for a
>> document
>> where the ontology is defined.
>>
>>>
>>> So my questions are:
>>>
>>> 1. What do you think is the expected output of
>>> http://dbpedia.org/ontology ? 300 million triples as turtle?
>>>
>> No. You would see the description of the ontology. In DB-pedia they
>> haven't done such redirection because
>> they are exposing both terms and classes with Pubby. But note that when
>> you look for a term, no instances
>> are returned.
>>
>>  2. How do you query all instances of type db-ont:PopulatedPlace via
>>> Linked Data ?
>>>
>> Via a SPARQL query:
>> select ?instance where{
>> ?instance a db-ont:PopulatedPlace.
>> }
>> If you don't want all the instances, then add a "LIMIT". That is why they
>> have a public endpoint, right?
>>
>> Another example. The recent PROV-O Ontology (with namespace URI
>> http://www.w3.org/ns/prov#).
>> If I have an endpoint with many prov:Entities published and I want them,
>> I can perform a query
>> as the one I did above. If I want to see the documentation of the term,
>> then I would ask for
>> http://www.w3.org/ns/prov#Entity and I would be redirected to it.
>> Doing an accept request for turtle to an ontology term would return the
>> owl file of the ontology,
>> not the instances of that term.
>>
>> Best,
>> Daniel
>>
>>>
>>> q.e.d from my point of view, as you wouldn't get around these practical
>>> problems.
>>>
>>> -- Sebastian
>>>
>>> Am 22.04.2013 11:50, schrieb Daniel Garijo:
>>>
>>>  Dear Sebastian,
>>>  This statement:
>>> "When you publish ontologies without data, you can use '#' . However, if
>>> you want to query instances via Linked Data in a database, you have to use
>>> '/' as DBpedia does for classes:
>>> http://dbpedia.org/ontology/PopulatedPlace"
>>>
>>> is not correct. You can use "#" to query instances via Linked Data
>>> databases. That is just the URI of the type. In fact if DBpedia had chosen
>>>
>>> "http://dbpedia.org/ontology#PopulatedPlace<http://dbpedia.org/ontology/PopulatedPlace>"
>>> instead of its current URI it would still be fine. It doesn't affect the
>>> query.
>>>
>>> I'm not going to enter in the debate of "# vs /", but normally it is a
>>> design decission that has to do more with the size of vocabularies than the
>>> instances.
>>>
>>> Best,
>>> Daniel
>>>
>>>
>>> 2013/4/22 Sebastian Hellmann <hellmann@informatik.uni-leipzig.de>
>>>
>>>>  Dear all,
>>>>
>>>> personally, I have been working on this for quite a while and for me
>>>> the best and easiest way is as documented here:
>>>> https://github.com/NLP2RDF/persistence.uni-leipzig.org#readme
>>>>
>>>> They are simple and effective and I couldn't imagine anything more.
>>>>
>>>> Note that I have also secured persistent hosting for the URIs (also an
>>>> important point).
>>>> Feedback welcome, of course.
>>>>
>>>> All the best,
>>>> Sebastian
>>>> Ontology:
>>>> http://persistence.uni-leipzig.org/nlp2rdf/ontologies/nif-core#
>>>>  # vs /
>>>>
>>>> When you publish ontologies without data, you can use '#' . However, if
>>>> you want to query instances via Linked Data in a database, you have to use
>>>> '/' as DBpedia does for classes:
>>>> http://dbpedia.org/ontology/PopulatedPlace
>>>>  <https://github.com/NLP2RDF/persistence.uni-leipzig.org#workflow>
>>>> Workflow
>>>>
>>>>    1. I edit the ontologies in turtle syntax with the Geany text
>>>>    editor (or a Turtle editor
>>>>    http://blog.aksw.org/2013/xturtle-turtle-editing-the-eclipse-way ),
>>>>    This allows me to make developers comments using "#" directly in the
>>>>    source, see e.g. nlp2rdf/ontologies/nif-core.ttl
>>>>    2. When I am finished I use rapper (
>>>>    http://librdf.org/raptor/rapper.html) to convert it to rdfxml (
>>>>    nlp2rdf/ontologies/nif-core.owl )
>>>>    3. I am versioning the ontologies in a folder with the version
>>>>    number, e.g. version-1.0 If somebody wants to find old ontologies, she can
>>>>    find them in the GitHub repository, which is linked from the ontology. I
>>>>    assume this is not often required, but it is nice to keep old versions. The
>>>>    old versions should be linked to in the comment of the ontology, see the
>>>>    header of nif-core.ttl
>>>>    4. Then I use git push to push the changes to our server
>>>>    5. (not yet) I use a simple OWL2HTML generator, e.g.
>>>>    https://github.com/specgen/specgen
>>>>    6. add yourself to http://prefix.cc, see e.g. http://prefix.cc/nif
>>>>    7. The versions are switched and published by these .htaccess
>>>>    rules, e.g.
>>>>    RewriteRule .(owl|rdf|html|ttl|nt|txt|md)$ - [L]
>>>>    # (in progress) RewriteCond %{HTTP_ACCEPT} text/html
>>>>    # (in progress) RewriteRule ^nif-core$
>>>>    /nlp2rdf/ontologies/nif-core/version-1.0/nif-core.html [R=303,L]
>>>>
>>>>    RewriteCond %{HTTP_ACCEPT} application/rdf+xml
>>>>    RewriteRule ^nif-core$
>>>>    /nlp2rdf/ontologies/nif-core/version-1.0/nif-core.owl [R=303,L]
>>>>
>>>>    RewriteRule ^nif-core$
>>>>    /nlp2rdf/ontologies/nif-core/version-1.0/nif-core.ttl [R=303,L]
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Am 19.04.2013 16:05, schrieb Prateek:
>>>>
>>>>  Hello all,
>>>>
>>>>  I am trying to identify a system which will provide versioning and
>>>> revision control capabilities specifically for ontologies. Does anyone have
>>>> any experience and idea about which systems can help out or if systems like
>>>> SVN, CVS can do the job?
>>>>
>>>>  Regards
>>>>
>>>>  Prateek
>>>>
>>>>  --
>>>>
>>>> - - - - - - - - - - - - - - - - - - -
>>>> Prateek Jain, Ph. D.
>>>> RSM
>>>> IBM T.J. Watson Research Center
>>>> 1101 Kitchawan Road, 37-244
>>>> Yorktown Heights, NY 10598
>>>> Linkedin: http://www.linkedin.com/in/prateekj
>>>>
>>>>
>>>>
>>>> --
>>>> Dipl. Inf. Sebastian Hellmann
>>>> Department of Computer Science, University of Leipzig
>>>> Projects: http://nlp2rdf.org , http://linguistics.okfn.org ,
>>>> http://dbpedia.org/Wiktionary , http://dbpedia.org
>>>> Homepage: http://bis.informatik.uni-leipzig.de/SebastianHellmann
>>>> Research Group: http://aksw.org
>>>>
>>>
>>>
>>>
>>> --
>>> Dipl. Inf. Sebastian Hellmann
>>> Department of Computer Science, University of Leipzig
>>> Projects: http://nlp2rdf.org , http://linguistics.okfn.org ,
>>> http://dbpedia.org/Wiktionary , http://dbpedia.org
>>> Homepage: http://bis.informatik.uni-leipzig.de/SebastianHellmann
>>> Research Group: http://aksw.org
>>>
>>
>>
>


-- 
Dimitris Kontokostas
Department of Computer Science, University of Leipzig
Research Group: http://aksw.org
Homepage:http://aksw.org/DimitrisKontokostas