Hi Mirko,

well the thing is, it wouldn't really work without a form a of reification (in my mind). There are use cases, where people prefer a simple knowledge representation of a semantic relation, and other ones, where people like to get a more detailed description about the semantic relation between two particulars. However, it is important to be able to semantically relate both of them. When I designed the Cognitive Characteristics Ontology[1], I struggled (again) with the same issues. Thereby, the Cognitive Characteristics Ontology includes two opportunities to model cognitive patterns. The first one is the representation of cognitive characteristics by using the semantic relation cco:cognitive_characteristic or better its more specialised sub properties, e.g. cco:interest, to associate the topics of the cognitive patterns to the users. The second opportunity is the object-oriented context reification of cco:cognitive_characteristic, cco:CognitiveCharacteristic, which is a general multiple purpose cognitive characteristic concept to describe cognitive patterns more in detail for a specific user or user group. However, to be able to model the semantic relation between the "shortcut relation" and its reification statement, one need a further mechanism, which is included into the Property Reification Vocabulary[2]. This vocabulary should enable a reasoning engine to apply the implications between a "shortcut relation" and its reification statement, however not directly on the RDF Statement however for all possible statement that uses the defined "shortcut relation" properties and reifications classes (incl. their related properties). In case of the Cognitive Characteristics Ontology[3] it enables you to decide between a skill in soccer player, an expertise in soccer and and interested in football watching (See [4]). Alternatively, you can apply Named Graphs, however in my mind, they are intended to represent 'external context' (especially provenance and trust), because their semantics are not really clear in that case. However, from my use case above, I like to represent 'internal context', as detailed description of a "shortcut relation". Don't hesitate to ask further question. This all is a work in progress and suggestions, comments and critics are very welcome.

Cheers,


Bob

[1] http://purl.org/ontology/cco/cognitivecharacteristics.html
[2] http://purl.org/ontology/prv/propertyreification.html
[3] http://purl.org/ontology/prv/propertyreification.html#sec-cco-example
[4] http://purl.org/ontology/cco/cognitivecharacteristics.html#sec-soccer-example

Am 13.10.2010 15:02, schrieb Mirko:
Hi all,
I try to understand alternatives to reification for Linked Data
publishing, since reification is discouraged. For example, how could I
express the following without reification:

@prefix dc: <http://purl.org/dc/elements/1.1/>.
@prefix foaf: <http://xmlns.com/foaf/0.1/>.

<http://ex.org/stmt>
   rdfs:label "Statement that describes user interest in a document"@de;
   rdf:subject <http://ex.org/User>;
   rdf:predicate foaf:interest;
   rdf:object <http://ex.org/Item>;
   dc:publisher <http://ex.org/Service>;
   dc:created "2010-10-13"^^xsd:date;
   dc:license <http://ex.org/License>.

<http://ex.org/User> rdf:type foaf:Agent.
<http://ex.org/Item> rdf:type foaf:Document.

Thanks,
Mirko

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