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Re: Granular dereferencing ( prop by prop ) using REST + LinkedData; Ideas?

From: Yves Raimond <yves.raimond@gmail.com>
Date: Mon, 5 Jan 2009 14:51:11 +0000
Message-ID: <82593ac00901050651k792e211gb81c0142dcdb74fb@mail.gmail.com>
To: "Bernhard Schandl" <bernhard.schandl@univie.ac.at>
Cc: "Richard Cyganiak" <richard@cyganiak.de>, "Aldo Bucchi" <aldo.bucchi@gmail.com>, "public-lod@w3.org" <public-lod@w3.org>

Hello!

On Mon, Jan 5, 2009 at 12:34 PM, Bernhard Schandl
<bernhard.schandl@univie.ac.at> wrote:
> On Jan 5, 2009, at 12:27 , Yves Raimond wrote:
>
>>> Also what is the point of providing explicit examples instead of just
>>> ASKing
>>> the endpoint if it returns useful data?
>>
>> Well, this is about auto-discovery - this is about finding the
>> endpoint that could answer that query, or finding a RDF document
>> holding this information.
>
> I think this is more the task of search engines and crawlers.

Indeed, and that's one of the thing voiD should try to address, IMHO -
"you're looking for this type of information? go look at this end
point"

> My concern is
> that it may be difficult to define the actual meaning of an example.
> Consider the statement you gave above:
>
>> <http://example.org/persons_nyc.rdf> void:example { :al_pacino
>> :birthPlace :New_York }.
>
> How should a client interpret the example? Does this mean the dataset holds
> information about :al_pacino (for which his birth place is an example),
> about the :birthPlace property (which information?), or about :New_York? Or
> does it hold data about things having a :birthPlace :New_York? Or does it
> describe the many :birthPlaces of :al_pacino? Maybe it describes a large
> number of relationships between :al_pacino and :New_York, of which
> :birthPlace is just one.

Indeed, and I think we mentioned SPARQL graph patterns in the
void:example discussion for that reason, e.g.:

<http://example.org/persons_nyc.rdf> void:pattern "{?person
:birthPlace :New_York}".

But I am not sure about embedding SPARQL graph patterns in RDF. It
raises some issues prefix-wise, etc.

>
>>> I think it might be sufficient to just publish which vocabularies are
>>> used
>>> by a certain endpoint. Even dbpedia uses a restricted set of
>>> vocabularies,
>>> so if a client would know in advance which vocabularies are used, it
>>> could
>>> decide if the data returned from this endpoint is useful. This could be
>>> even
>>> more restricted to publishing "application profiles" of vocabularies;
>>> i.e.,
>>> subsets of the vocabularies that are actually used within a dataset.
>>
>> Hmm. Won't this end-up defining almost one application profile per
>> dataset or RDF documents?
>
> Exactly.
>
>> Are there really canonical application profiles?
>
> No. Vocabularies are canonical; an application profile is specific for one
> application, i.e., one data set or one client application.
>
>> For DBTune, for example, it wouldn't be useful to say that
>> each dataset use the Music Ontology, FOAF, etc. You need a finer grain
>> to state that Jamendo deals with tags, artists, and Creative Commons
>> records, Musicbrainz with editorial information, the BBC John Peel
>> sessions with musical performances, etc.
>
> That is was I meant by saying "subsets of the vocabularies". I imagine
> application profiles not on the level of entire vocabularies, but on the
> element level. For instance, an application profile for your example could
> point to the :birthPlaces property, stating that this property is used in
> this dataset. The creation of such profiles could be automated entirely,
> IMHO.

It sounds similar to Richard's proposal, for the birthPlace example -
what would it look like for an example involving more than one
property (e.g. birth places + birth dates, or GPS coordinates attached
to a person)?

Cheers!
y

>
> Best regards, Bernhard
>
>
Received on Monday, 5 January 2009 14:51:48 UTC

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