On Mon, 2009-12-21 at 22:13 +0200, Nina Jeliazkova wrote:
> Martin Guetlein wrote:
> > Hello All,
> >
> > 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?
> >>     
> >
> > Apart from feature value type I would like to have a "feature range"
> > as well. This should be a property of a feature, which gives me all
> > the possible feature values of a nominal feature (e.g. active,
> > moderately-active, inactive). This is needed when validating a
> > prediction algorithm.
> >
> > What do you think?
> >   
> 
> Yes, we might extend  opentox.owl class with a NominalFeature , a
> subclass of Feature and introduce a property like ot:nominalValues ,
> which allows specifying set of String values. If a dataset includes such
> NominalFeature , one would be able to retrieve set of values ,that are
> allowed by inspecting values of the ot:nominalValues property. 
> 
> This will be more or less equivalent to Weka nominal attributes, where
> the allowed values are listed in the ARFF file header .
> 

Wouldn't it be better and simpler if the property ot:nominalValues has
as domain ot:Feature instead of ot:NominalFeature. I mean, do we need to
extend ot:Feature to ot:DoubleFeature, ot:StringFeature and
ot:NominalFeature? I think it would be better if we intoduced the
property ot:hasDataType and then introduce a set of datatypes based on
the existing XSD ones. for example:

<featureUri> <ot:hasDataType> <dataTypeURI>
or
<dataTypeUri> <ot:isA> <ot:Nominal>
<dataTypeUri> <ot:acceptsValue> "1"
<dataTypeUri> <ot:acceptsValue> "1"
<dataTypeUri> <ot:acceptsValue> "1"


> Best regards,
> Nina
> > Best regards,
> > Martin
> >
> >
> >   
> 
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