I'm using Protege to develop an ontology that will include some things that are already described in DBpedia. Let's say I want to include a class 'Cities' and have 'Berlin' as an individual. My Berlin will have some properties the DBpedia Berlin doesn't but otherwise I'd like to 'reuse' DBpedia's Berlin.
Do I need to define my own Berlin and then use rdf:seeAlso or can I somehow import DBpedia's Berlin and add some properties?
If it's sufficient to simply talk about the same individual, just add the individual to your ontology (i.e., create an individual with the IRI http://dbpedia.org/resource/Berlin) and add whatever else you need.
You could also create an individual with your own IRI, e.g., http://stackoverflow.com/questions/19703414/Berlin and assert that it's owl:sameAs http://dbpedia.org/resource/Berlin. You're creating OWL individuals with Protege, and DBpedia is using an OWL ontology, and owl:sameAs is what you'd use to express the fact that two individuals are the same.
rdfs:seeAlso is just for finding related information, e.g., a document about some resource, or the standard in which it's defined, etc. Even in the if you have
http://stackoverflow.com/questions/19703414/Berlin rdfs:seeAlso http;//dbpedia.org/resource/Berlin
and someone retrieves http;//dbpedia.org/resource/Berlin and sees a bunch of triples with that subject, there's nothing telling them that
http;//dbpedia.org/resource/Berlin owl:sameAs http://stackoverflow.com/questions/19703414/Berlin
which is really the important thing.
