How can the HPSG and Universal Dependencies communities benefit each other for some integration? Alexandre Rademaker
FrancisBond: There was some work some time ago using CoNLL dependencies to constrain the output of parses in delphin to build a partially annotated treebank from there (or as a first step in annotation). It was reasonably successful. There were small issues due to tokanization differences. One dependency produced by Stephan Oepen's group in Norway filled a "lexicalized thing" from this so that was more similar to UD, so there is code to do that.
AlexandreRademaker: Good to know!
BertholdCrysmann: Treebanking is one of the big bottlenecks in grammar engineering. Can the scribe provide a pointer to this success? Pointers (thanks, Francis): http://www.aclweb.org/anthology/W09-1204 https://folk.uio.no/rdridan/papers/iwpt13-dt.pdf
DanFlickinger: As far as converting to/from UD, you can restrict yourself to the big stuff and leave fine points are under-determined, as Stephan did.
BertholdCrysmann: Even with partial disambiguation, you should be able to train models on that. You have to throw a lot of data at it for the domain.
JohnCarroll: So it's domain specific (the dependency parsers)?
AlexandreRademaker: Depending on the parser, in the case of Portuguese, some parsers fair badly with morphology.
AlexandreRademaker: We started with a rule based grammar and refined based on a corpus- surely we're not the only group to do that. This is good for checking annotation consistency.
EmilyBender: DMRS to UD doesn't make sense because that would be mapping semantics to syntax. But there is a dependency that comes off of our syntax trees, so we could do that mapping. But why? That's a lossy mapping. We have more info than UD. Is it just to give UD more data?
AlexandreRademaker: It could help to advocate in favor of HPSG-- we (DELPHIN) could help improve UD trees. This sounds like a political question, so it's difficult to answer. One point I'd like to raise: from my position in the industry, most people don't care about precision. So we (industry) want to benefit from more parses, but we don't want to be the sole owner of a grammar that never gets used again. We want to get grammars on top in industry, but our priority isn't precision, it's maintaining and increasing. Being connected with huge data communities benefits both groups.
BerndKiefer: Coming back to the old idea of hybrid robust processing could be interesting. If we combined UD and HPSG in cases where we can't get a good parse, that could indicate where we need to relax constraints. This can hint at ways to improve both grammars. There is a lot in there for the "medium level expert".
GuyEmerson: One benefit of delphin to UD is a plug for delphin tools. This is a selling point for us.
EmilyBender: Maybe our UD annotations would be even more consistent than theres.
GuyEmerson: We could go from our parse tree to UD in a similar style to DMRS.
EmilyBender: Antske did something like this. Maybe it wasn't UD standard.
GuyEmerson: So we could coerse that into the UD framework.
DanFlickinger: There was an attempt to map the Alpino treebank to UD. So there's code. There are 50 lines that do almost everything and 1000 lines handling small cases. We could do something analogous to get the big stuff with small effort. I think that's the most tempting reason-- to package this and make it usable, make it visible and get feedback so that we can refine. Some other groups are tying to do this (LFG). It's expensive so give it to a grad student.
AlexandreRademaker: I've suggested to my people that they can mine trees in treebanks for information. They acknowledge that this is a good idea. So I think what Dan suggests is something that i could interest my clients in. We start with small course tree and build to something richer/more fine-grained. Real projects could benefit.
BertholdCrysmann: follow up on Dan's comment about Alpino- do I remember correctly that the semantic output is already kind of a dependency structure?
DanFlickinger: Yes. It's still syntax. We shouldn't try to map our semantics but our syntax surely.
EmilyBender: I overheard at Olso that they want to convert UD to DMRS. Is that happening?
DanFlickinger: I don't know. There was uncertainty how useful that would be. The mismatches in fundamental things (ambiguity etc.) is more annoying than interesting. A lot of information can be lost. Ultimately it was ruled uninteresting, not unuseful. But the question is what's the motivation?
EmilyBender: I thought it was to learn more about composition.
JanBuys: One advantage to leverage UD representations is to improve coverage. For example the lexicon in our grammar might be restricted-
EmilyBender: Bootstrap that coverage to improve lexical disambiguation?
JanBuys: Exactly. It wouldn't be perfect but it could help
JohnCarroll: There have been discussions going back a ways- years ago we produced a set of 500 sentences that were annotated and someone else produced 500 and we compared them and in fact got very different outputs with different dependency annotations.
DanFlickinger: But one goal of UD is a standardized system. The idea was: don't do pairwise mappings- do one time mappings to ud and compare those.
JohnCarroll: In those days it was just about comparison, now its about training purposes.
JanBuys: In the other direction- would it be possible to use the grammar to make the UD annotation process more efficient or consistent? Only for dependencies (not MRS), they can leverage our infrastructure.
AlexandreRademaker: Yes, that's the first thing I thought of. Our Portuguese UD bank is small and we'd like to grow it quickly. Any tool to help with consistency would be a huge help.
FrancisBond: Oslo has been working on this-- Dan, is there a DM to UD converter?
DanFlickinger: A script form MRS to DM exists.
EmilyBender: That's just for semantics. There is a script for syntax as well.
DanFlickinger: But i don't know if there is one to get to UD. Stephan would be a good person to talk to about this.
WeiweiSun: You could just use a statistical model for this. There are many treebannks for Mandarin and many papers discuss this kind of conversion to create heterogeneous treebanks, so we don't need to reinvent this from scratch. Another thing- why UD?
AlexandreRademaker: Because Google, Stanford an Prague were the first three big groups.
DanFlickinger: An attempt at a positive spin on why these are so popular is that they take on a very interesting problem- there is an intersection of interests among research groups- not a total overlap but there is non-empty intersection. Most groups can make use of something in those treebanks. Language independence is one of those interests. There are levels of representation that are of some use to a variety of groups (even typologists).
AlexandreRademaker: What Dan just said is summarized by Manning.
DanFlickinger: Manning's Law does hit on this.
EmilyBender: And it's a good name.
JohnCarroll: And they've learned from CoNNL.