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Re: Blank nodes in descriptor sets - a proposal to deal with this using Occam's Razor

From: Stasinos Konstantopoulos <konstant@iit.demokritos.gr>
Date: Thu, 17 Jul 2008 14:56:50 +0300
To: Phil Archer <parcher@icra.org>
Cc: Public POWDER <public-powderwg@w3.org>
Message-ID: <20080717115650.GD4871@iit.demokritos.gr>

On Wed Jul 16 16:14:29 2008 Phil Archer said:

> Thanks for putting even more time into this.
>
> If I understand you correctly it would be fair to allow this:
>
> <ex:material>
>   <ex:Wood>
>     <ex:colour>brown</ex:colour>
>   </ex:Wood>
> </ex:material>
>
> but we should explain that this means that "there should be a resource  
> out there which is of the type ex:Wood that has the color brown, and  
> that this is the value filler for our properties." Although this may be  
> semantically valid, such a construct is usually inappropriate for use in 
> POWDER.

Indeed. So dropping this from descriptions would be no big loss, as it
is hardly expected to be used. But would be a big loss if also dropped
from attribution elements, disallowing constructs like:

<attribution>
  <issuedby>
    <foaf:Person>
      <foaf:name>Stasinos</foaf:name>
      <foaf:phone rdf:resource="tel:210650"/>
    </foaf:Person>
  </issuedby>
</attribution>

We could, however, mention in the text that it is bad practice to
re-define entities that already have FOAF or DC descriptions of
themselves.

> Giving the node an ID using rdf:about effectively creates a new  
> vocabulary term that is duplicated every time the POWDER document is  
> processed and although, again, this may be useful in some circumstances  
> it's generally better to use a pre-defined term if possible.

Most definitely better, if possible. The question is about situations
where there is no appropriate pre-defined vocab item.

> Finally, since POWDER transports RDF/XML, it is not unreasonable to  
> expect a POWDER Processor to be do at least minimal processing of RDF  
> and not just always as XML.

Indeed.

Note: I will only be "mildly on-line" starting today and during next
week and "really off-line" the week after that, but I think that we are
converging, so I am not wooried that I am leaving s'thing important in
the middle.

About owl:Ontology, like I wrote yesterday, I would like to leave the
rdf:Description door open until after summer vacations, but if the group
feels this should be resolved by LC, then by all means go ahead.

s
Received on Thursday, 17 July 2008 11:57:32 GMT

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