The meeting this week started off with a discussion of LDA, and moved on to a discussion about Twitter. We went over the graphical model specification of LDA as well as the way it was modified to create Latent LDA, the method used in the focus paper. We concluded that Latent LDA was an interesting extension to LDA that was able to handle supervision more successfully than the more common Supervised LDA.
In the Twitter-related half of the discussion, we discussed general properties of Twitter, as well as a method for identifying discourse acts in threads of tweets. The discourse act paper had a major flaw in that its only quantitative evaluation did not work, and it did not clearly specify the problem it was trying to solve. The methods that it used also seemed more suitable for longer conversations, rather than the 3-6 message threads present in the Twitter data. We also discussed general properties of Twitter, but did not really conclude anything on that topic.