So I had an excellent time at day 2 of SIGDial, although I unfortunately missed the last couple of sessions due to a clash with the Discourse Annotation tutorial I attended. On that note, it seems strange (but presumably unavoidable) that such closely aligned sessions should clash.

Heard some interesting talks that I won’t have time to really do justice to in summarizing them here (I’m sitting in the corridor at the main Coling-ACL conference, taking advantage of a break in sessions). Most interesting work for me included:

• Work using GraphBank – which looks at discourse structure as graph-based rather than tree based. This allows non-local (i.e., long distance) discourse links to be modelled, which is sometimes an advantage in real discourse. GraphBank, while an interesting idea, is not without its problems however – one specific issue is that it seems to conflate some relations, in particular actual causation with intention or purpose, which can lead to some strage annotations.
• Work from Tilburg University on (yet another) dialogue act taxonomy, called DIT++. How is it different from something like DAMSL? This isn’t entirely clear, but perhaps a point of differentiation seems to be a more elaborate and fine-grained set of feedback functions and dialogue control aspects. In general, given that it is a multi-dimensional annotation scheme, there are the usual problems with inter-annotator agreement. To attempt to improve their evaluation scores, the particular work presented looked at developing evaluation metrics that better model the performance of such hierarchical schemes, where coarse-grained agreement is usually ignored if fine-grained disagreement occurs (e.g., using kappa as a measure of agreement). Unfortunately, that actual weighted metrics proposed seemed rather preliminary and arbitrary, though there is clearly a need for such work.
• A high-level presentation from David Traum on work with Question Answering characters. The main message I took out of his talk was a desire to define the ‘science’ of content creation across different modalities and methods (text, speech and graphics are their focus)

Otherwise, Coling/ACL has been a rather intense experience so far – just getting towards finishing day 4 of consecutive conference days, with another 5 still to go (although tomorrow is actually an excursion day). ACL is awesome fun though – a hugely impressive and inspiring group of people from all over the planet.