Re: Drilling into the LOD Cloud

I think you're overlooking something....
If you're using dc:author to state

<http://dbpedia.org/resource/R%C3%B6yksopp> dc:author example:me

( which translates to: "I *created Royksopp*, the music band" )

And then Umbel states that *they created* the music band ( I made this
up for the example ).

<http://umbel.org/umbel/ne/wikipedia/R%C3%B6yksopp> dc:author ex:someoneElse .

you will indeed run into problems when equating the two IDs.

<http://dbpedia.org/resource/R%C3%B6yksopp> owl:sameAs
<http://umbel.org/umbel/ne/wikipedia/R%C3%B6yksopp>

But, AFAIK, this is *incorrect usage of dc:author* and not a design
flaw re. owl:sameAs.
Luckily, neither UMBEL nor  DBpedia seem to be using dc:author incorrectly.

Authorship metadata should not be attached to the ID for the concept,
but to the vocabulary namespace or through other indirection.
Which brings up another point: how do you state that a URI belongs to
a given vocabulary.
- URI opaqueness plays against here
- is this really something we want/need?
- ...

If what you intend to equate is a document ( which usually have dc:*
metadata ) with another doc that has different metadata, stop and
rethink it. You might be wanting to equate the concepts they
reference.

A

On Sun, Sep 28, 2008 at 6:30 PM, Damian Steer <d.steer@bristol.ac.uk> wrote:
>
>
> On 28 Sep 2008, at 19:01, Kingsley Idehen wrote:
>
>>
>> Dan Brickley wrote:
>>>
>>> Kingsley Idehen wrote:
>>>>
>>>> Then between UMBEL and OpenCyc:
>>>>
>>>> 1. owl:sameAs
>>>> 2. owl:equivalentClass
>>>
>>> If these thingies are owl:sameAs, then presumably they have same
>>> IP-related characteristics, owners, creation dates etc?
>>>
>>> Does that mean Cycorp owns UMBEL?
>>
>> Dan,
>>
>> No, it implies that in the UMBEL data space you have equivalence between
>> Classes used to define UMBEL subject concepts (subject matter entities) and
>> OpenCyc.
>
> I think Dan's point is that owl:sameAs is a very strong statement, as
> illustrated by the ownership question. If opencyc:Motorcyle
> owl:equivalentClass umbel:Motorcycle then they have the same extension.
> Informally, any use you make of one as a class can be replaced by the other
> without changing the meaning of the whole. However if the are owl:sameAs
> they name the same thing, so dc:creationDate, dc:creator, cc:license,
> rdfs:isDefinedBy etc etc are the same for each, which strike me as unhelpful
> side effects. owl:equivalentClass is the vocabulary mappers' friend :-)
>
> Damian
>
>
>



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Received on Monday, 29 September 2008 04:17:13 UTC