Well, the first part of the project got scrapped, because it turns out people behave like a particle only under trivial conditions (or I modeled the problem wrong, that's also possible). The idea was that, since we know which target is attracting a pedestrian's attention, we could model both as a particle being attracted to a target (and being repelled by distractors). Whatever little remained of that idea ended up in another paper[1]. As for the grammar, the best I have is this paper[2].

I apologize for not having anything less dry to read than papers - as I'm not looking for another job, I don't feel the need to get off my ivory tower too often.

[1] http://ivan-titov.org/papers/emnlp13.pdf (poster: http://www.ling.uni-potsdam.de/~villalba/publications/refexp...)

[2] http://www.ling.uni-potsdam.de/~koller/papers/chart-gre-14.p...