As guergana mentioned ctakes has a rule based negation detection module.
In addition ytex adds a negex based analysis engine. Both approaches are
very sensitive to sentence splitting (see previous threads on alternative
sentence splitters).
An additional advantage of rule based negation is you do
As I was reading this thread I had the same thought as Tim, perhaps a
combination. It seems over the perfect training corpus this wouldnt be
necessary, but perhaps as a stop gap the "ensemble" approach for some using
your training data but working in a diff corpus (not that I really have the
time t
Tim, I like your idea of a hybrid approach. I've thought about trying a
hybrid approach in the past myself, but haven't had a chance to try it or
seen any papers on it. It seems you could do it by either treating the
NegEx output simply as a feature in the ML model or combining the output of
NegEx
Hi Michael,
I'm somewhat sympathetic to that opinion. But we did a bunch of
experiments and it seemed to us that negex was too hand-tailored for a
specific dataset and that our new module did better across datasets and
overall. The tradeoff is that it is harder to improve and it sometimes
gives une
...@northwestern.edu]
Sent: Wednesday, December 31, 2014 11:22 AM
To: dev@ctakes.apache.org
Subject: Re: cTakes polarity problem
I think this demonstrates that machine learning is not the right approach to
the negation/polarity problem.
Michael Gurley
m-gur...@northwestern.edu
312 925 3268
I think this demonstrates that machine learning is not the right approach
to the negation/polarity problem.
Michael Gurley
m-gur...@northwestern.edu
312 925 3268
Northwestern University Clinical and Translational Sciences Institute
(NUCATS)
http://www.nucats.northwestern.edu
Rubloff Building
750
Hi Yu,
The new polarity module is machine-learning based so it is not always
easy to diagnose accuracy issues. But generally it might mean there was
no example like that in the training data. It was trained on multiple
corpora, but sometimes certain phrases slip through the cracks, and
"Deny hepat
I have a quick question about CTAKES.
I am using AE “AggregatePlaintextUMLSProcessor.xml” and want to get some
negation results by referring to polarity attribute.
However, it turns out, for example “Negative for hepatitis”, is not negated. I
think it is weird and I tried “No hepatitis”, “ Denies
