Sumithra Velupillai attended The Fourth International Symposium on Languages in Biology and Medicine (LBM 2011) at the Nanyang Technological University in Singapore, December 14-15.
At LBM 2011, Sumithra presented the paper Automatic Classification of Factuality Levels – A Case Study on Swedish Diagnoses and the Impact of Local Context. In this paper, The Stockholm EPR Diagnosis-Factuality Corpus is described and used for building automatic classifiers. The classifier obtains promising results (best overall results are 0.699 average F-measure using all classes, 0.762 F-measure using merged classes), using simple local context features. Preceding context is more useful than posterior, although best results are obtained using a window size of 4. Lower levels of certainty are more problematic than higher levels, which was also the case for the human annotators in creating the corpus. A manual error analysis shows that conjunctions and other higher-level features are common sources of errors.
Happy LBM 2011 participants after a wonderful banquet at Chef Chan's Restaurant