Re[2]: [] or <> as root ?

Hi Henry,

  as  we  have  just  been  discussing  related  issues in the NEPOMUK
  project [1], I wanted to add our arguments.

> After a good conversation on #swig with Sandro Hawke [1] I have come
> to the conclusion that using an anonymous node [] is better. It makes
> it easier to merge graphs, and I have a feeling that should be the  
> primary principle when creating ontologies: making graph merges easy.
Agree,  merging  graphs  is  important.  But  (!) the default rule for
merging  bnodes  is to treat them as different unless exactly the same
statements  are  made  about them in both graphs. In reality, two news
stories will not be merged, if e.g. one has a slightly different title
now or an additional statement added.

Handling  blank  nodes  in  versioning  is generally not funny, so one
strategy might be to avoid them [2].

Merging  nodes  is  domain-specific.  In FOAF, two entities having the
same  email-adress or an equivalent hash can be merged. This obviously
works  only  for  things that have an email address. For news stories,
one needs a clear concept of what is 'one news story'. Updating a news
story could be seen as another, related story or as new content of the
existing story.


Kind regards,

  Max Völkel

[1] http://nepomuk.semanticdesktop.org
[2] http://www.aifb.uni-karlsruhe.de/Publikationen/showPublikation?publ_id=1163
--
Dipl.-Inform. Max Völkel, Universität Karlsruhe / FZI
            nepomuk.semanticdesktop.org
voelkel@fzi.de   +49 721 9654-854   www.xam.de

First Workshop on Semantic Wikis: http://semwiki.org




Wednesday, March 15, 2006, 12:28:49 PM, you wrote:


> The CIFP I mention below is a problem when people update an entry  
> without changing the updated time stamp, and exists because the atom  
> working group did not want (or could not) be clear about what good  
> identity criteria are. By doing graph updates as explained below we  
> should be able to deal with that problem. We could also drop the  
> CIFP. That should in part be decided by seeing what advantages it  
> provides...

> Tricky question though...

> Henry

> [1] http://chatlogs.planetrdf.com/swig/2006-03-15.html#T09-38-04

> On 13 Mar 2006, at 12:29, Henry Story wrote:
>> Here is a little puzzle regarding atom that it would be interest to
>> have some feedback from the larger Semantic Web community. We are
>> wondering if there are best practices guidelines for updating
>> semantic web data found on the web. We have an ontology for the Atom
>> (rfc4287) spec called AtomOwl [1], that would allow us to GRDDL atom
>> documents into graphs.
>>
>> This thread started off with the question as to whether one should map
>>
>>   <entry>
>>         <title>Atom-Powered Robots Run Amok</title>
>>         <link href="http://example.org/2003/12/13/entry"/>
>>         <id>tag:example.com,2003/blog/entry1</id>
>>         <updated>2003-12-13T18:30:02Z</updated>
>>         <summary>Some text.</summary>
>> </entry>
>>
>> to
>>
>>            <> a :Entry;
>>               :title [ :value "Atom-Powered Robots Run Amok";
>>                        :type "text/plain" ];
>>               iana:alternate <http://example.org/blog/entry.html>;
>>               :id <tag:example.com,2003/blog/entry1>;
>>               :updated "2003-12-13T18:30:02Z"^^xsd:dateTime;
>>               :summary [  :value "some text";
>>                           :type "text/plain" ] .
>>
>> or to
>>
>>            [] a :Entry;
>>               :title [ :value "Atom-Powered Robots Run Amok";
>>                        :type "text/plain" ];
>>               iana:alternate <http://example.org/blog/entry.html>;
>>               :id <tag:example.com,2003/blog/entry1>;
>>               :updated "2003-12-13T18:30:02Z"^^xsd:dateTime;
>>               :summary [  :value "some text";
>>                           :type "text/plain" ] .
>>
>>
>>

Received on Saturday, 18 March 2006 10:14:00 UTC