P (s|λ) can be calculated efficiently using the forward-backward procedure which makes the estimate for the total probability of all state paths that go through filler states straightforward to be: Now it is clear to see that, if the calculated P (s, Q f iller |λ) > P (s, Q bg |λ), then segment s is considered more likely to have filler occurrence(s).
the effect of the segmentbased HMM extraction goes beyond applying a post-processing step to the document-based HMM extraction, since the latter can only reduce the redundancy but not improve the F1 scores.