Tobias Girschick wrote:
> Hello Nina,
>
> On Mon, 2009-12-21 at 14:21 +0200, Nina Jeliazkova wrote:
> [...] 
>   
>>> RDF representations, structurally, contain much more (meta)information
>>> about the objects they describe than ARFFs, so this piece of
>>> information in the text/x-arff (the datatype of each feature) IMHO has
>>> to be included in the RDF or at least - in order not to modify the RDF
>>> standards we adopted in API 1.1 - we should use proper XSD datatypes
>>> for every value. After all, its not 1^^double, 1^^string and
>>> 1^^nominal is not the same and won't (shouldn't) be handled the same
>>> way by a training algorithm.
>>>       
>> Yes, especially for nominals, it would be better to introduce subclass
>> of Feature, rather than using XSD types for denoting the types.  I might
>> try to extend opentox.owl next days.
>>     
>
> This would be great. At the moment, classification is not possible as it
> relies on a nominal target feature. Will this be reflected in the
> text/x-arff, too?
>   
I wrote some new code for generating Instances from RDF , but it is not
yet used by the published services.  It does create nominal attributes
and takes into account numerics/string mix.

https://ambit.svn.sourceforge.net/svnroot/ambit/trunk/ambit2-all/ambit2-www/src/main/java/ambit2/rest/rdf/RDFInstancesIterator.java

Best regards,
Nina

P.S. [Silently, trying to hide from Ruby guys]: If you prefer serialized
Java object of Weka Instances, it could be possible via restlet
MediaType.APPLICATION_JAVA_OBJECT :)
> Best Regards,
> Tobias
>
>