Hello Piero, Piero Molino schrieb: > Hello everyone, > > Now, i don't know where to start from for doing this (my software is > in java). Wich dump should i use? Anyone knows reliable opensource > libraries for managing owl (i never used it before so i'm really new > to it)?
There are several ways to achieve this depending on how exactly you measure distance between classes. One way would be to use SPARQL and query the official endpoint, e.g. using Jena [1]. The second way would be to use the OWL API [2]. What to do specifically, depends on your distance metric. For instance, you could ask yourself whether two classes A1 and A2 are similar in your scenario if A1 is a super class of A2.(?) A simple way would be to query parent classes of A1 until a class A' is found, which is also parent of A2. You then get a path from A1 to A2 with A' as middle element and can measure its length. Due to the existence of owl:Thing such a path always exists. Google comes up with a few papers with more sophisticated approaches related to measuring distance in ontologies [3,4,5], which might be helpful. > Is there some kind of limitation i'm not aware of that can > stop me doing what i described? In your description, you assume that there is one class for each object. In general, an object can be instance of several classes. In particular, it can also belong to several "most specific" classes. However, this does seem to be rare in the DBpedia ontology (and you can generalise the above description to this case). Kind regards, Jens [1]http://jena.sourceforge.net/ [2]http://owlapi.sourceforge.net/ [3]http://www.aaai.org/Papers/Workshops/2005/WS-05-01/WS05-01-015.pdf [4]http://www.di.uniba.it/~cdamato/kes2008-AKS_Track.pdf [5]http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?tp=&arnumber=4444245&isnumber=4444190 -- Dipl. Inf. Jens Lehmann Department of Computer Science, University of Leipzig Homepage: http://www.jens-lehmann.org GPG Key: http://jens-lehmann.org/jens_lehmann.asc ------------------------------------------------------------------------------ Enter the BlackBerry Developer Challenge This is your chance to win up to $100,000 in prizes! For a limited time, vendors submitting new applications to BlackBerry App World(TM) will have the opportunity to enter the BlackBerry Developer Challenge. See full prize details at: http://p.sf.net/sfu/Challenge _______________________________________________ Dbpedia-discussion mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/dbpedia-discussion
