Am 20.07.2011 um 21:20 schrieb Jörn Kottmann:
> So in the sample above a user defines this type system:
>
> Type: com.foo.Token
> Feature: double tokenConfidence
> Feature: String posTag
> Feature: double posConfidence
>
> The tokenizer also defined its type system:
> Type: opennlp.Token
> Feature: float confidence
>
> And one more type system for the pos tagger:
> Type: opennlp.POSToken
> Feature: float confidence
> Feature: String tag
>
> The user defined AAE only knows the user type system and needs to
> define "rules" which tell it how to transform opennlp.Token annotations
> to com.foo.Token annotations, and then it needs a rule to transform
> a com.foo.Token into an opennlp.POSToken, and back.
>
> Sure this is also already possible today, by writing these type mapping AEs,
> as you would need to do for JCas. But I think having better framework
> support for this would make it easier.
In DKPro we have a Token type and a POS from which several types inherit (V,
NP, ADJ, etc.) The Token type has a feature of type POS on which we set an
instance e.g. V or NP.
Token t = new Token(jcas);
t.setPos(new N(jcas));
We find this quite convenient because it allows us to easily select particular
type from the CAS, e.g.
for (N noun : select(jcas, N.class)) {
... do something with nouns ...
}
Similarly it's convenient to write rules over POS tags in TextMarker with our
type system.
With such type systems or with type systems using lists, arrays etc, a simple
rule-based mapping won't work I think. JCas is a nice convenience API, but I
don't think its more. I'm not sure if the effort of implementing a mapping rule
framework is worth the outcome.
Cheers,
Richard
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Richard Eckart de Castilho
Technical Lead
Ubiquitous Knowledge Processing Lab
FB 20 Computer Science Department
Technische Universität Darmstadt
Hochschulstr. 10, D-64289 Darmstadt, Germany
phone [+49] (0)6151 16-7477, fax -5455, room S2/02/B117
[email protected]
www.ukp.tu-darmstadt.de
Web Research at TU Darmstadt (WeRC) www.werc.tu-darmstadt.de
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