Overview

The LinGO Redwoods treebank is a collection of hand-annotated corpora analysed with the LinGO ERG. For each utterance from a corpus, the treebank records (in principle) all analyses hypothesized by the grammar, together with an annotator decision as to which reading is preferred in context.

The key innovative aspect of the Redwoods approach to treebanking is the anchoring of all linguistic data captured in the treebank to the HPSG framework and a generally-available broad-coverage grammar of English, viz. the LinGO English Resource Grammar. Unlike existing treebanks, there is no need to define a (new) form of grammatical representation specific to the treebank (and, consequently, less dissemination effort in establishing this representation). Instead, the treebank records complete syntacto-semantic analyses as defined by the LinGO ERG; tools are provided to extract many different types of linguistic information at varying granularity.

Other relevant aspects of the Redwoods treebank include the integration of alternate, though dispreferred analyses for each utterance and the dynamic nature of the annotations: as the underlying grammar evolves and improves its analyses, there is a provision for a (nearly) fully automated update of the treebank against a version of the original corpus analysed with the revised grammar. As a methodological results, part of the Redwoods data are now regularly maintained as part of the grammar regression cycle with each new release of the ERG.

Current Development Status

As of October 2011, we are in the process of releasing the 45,000-sentence Seventh Growth, a substantially enlarged new revision of the Redwoods treebank, consisting of data sets from several distinct domains, including not only the Verbmobil and ecommerce corpora from earlier releases, but now also data from the LOGON Norwegian-English MT corpus, the WeScience 100-article portion of the English Wikipedia and a portion of the semantically tagged subset of the Brown corpus (SemCor). The version of the grammar used in parsing this data is "ERG (1110)".

The following table summarizes the Seventh Growth in terms of the total number of utterances, average string length, and average ambiguity rates for three sub-divisions, viz. rejected items (t-active = 0), fully disambiguated items (t-active = 1), and a small number of items for which annotators considered more than one analysis active (t-active > 1), typically where the ambiguity resides in tokenization alternatives. The profile name abbreviations are as follows: CB = Cathedral and Bazaar essay, CSLI = syntactic test suite, EC* = ecommerce corpus, FRACAS = semantic test suite, HIKE and JH* and PS* and RONDANE and TG* = LOGON corpus, MRS = semantic test suite, RTC* = Tanaka corpus, SC* = SemCor corpus, TREC = TREC 9 corpus, WS* = WeScience corpus.

Earlier relevant Redwoods revisions include the Second Growth, Third Growth, and Fifth Growth.

Data Format

Like the previous Redwoods Fifth Growth revision, the Seventh Growth is distributed in [incr tsdb()] profile form exclusively (see below for instructions on how to expand the data into a textual export format), but we have limited the number of dispreferred analyses per item to a maximum of the 500 best analyses according to our MaxEnt model trained on an interim version of this treebank. In principle, Redwoods users could use the LKB or PET parsers to obtain the complete set of analyses and then use the [incr tsdb()] update facility to automatically produce a version of the treebank against the unrestricted profile. However, we expect that the reduced distribution provides a sufficiently large portion of the dispreferred analyses for high-quality stochastic modelling and that the substantial reduction in overall size will actually benefit experimentation.

(fix: update instructions for LOGON 'redwoods' script)

See the LkbInstallation instructions for details, but the following should just be sufficient to obtain a full installation of the LKB, ERG, [incr tsdb()], and Redwoods Seventh Growth data for the Linux (x86) environment (the choice of DELPHINHOME, the root directory for the DELPH-IN source tree, can be varied, of course; the example below assumes a sub-directory `delphin' in the user home directory): 

  export DELPHINHOME=${HOME}/delphin
  wget http://lingo.delph-in.net/etc/install
  bash install --redwoods

Expanding and Exporting

Assuming a functional installation of the LKB, ERG, and [incr tsdb()], the process of exporting all or parts of the Redwoods Seventh Growth data into a collection of plain text files can be fully automated by virtue of a shell script provided in the [incr tsdb()] data directory. By default, the script will include the following representations in the export

FIXME below

Setting the parameter *redwoods-export-values* in the script (see below) to a sub-set of the above may result in significant savings in export time and disk space requirements. The default set of (close to all) export representations requires several cpu days and around 20 gbytes of disk space (as a set of gzip(1)-compressed files) for the full Redwoods Seventh Growth. Following is an example session to export just the VM6 section: 

  cd $DELPHINHOME/lkb/src/tsdb/home
  ./export redwoods/jun-04/vm6/04-06-11

A full export can be fairly memory-intense for highly ambiguous items, i.e. it is advisable to run the above in a suitable machine (with, say, two gbytes of RAM or above). Consult the export script for further configuration options, and ItsdbTreebanking/ItsdbExporting for various possible formats.

For example, to export triples from only the first parse of a non-treebanked profile: 

./export --binary  --condition "result-id=0" --format triples PROFILE

Bibliography

Following is an incomplete selection of publications on the creation and use of the Redwoods treebank.

An overview presentation on many of the methodological aspects of the Redwoods initiative is available from an invited presentation at the 2003 Treebanks and Linguistic Theories workshop.

Acknowledgements

The Redwoods treebank has been under active development at the CSLI LinGO Laboratory since sometime early in 2001. The annotation environment was built from the combination of the LKB tree comparison window (originally developed by Rob Malouf) and the [incr tsdb()] profiling tools; Stephan Oepen did the bulk of the Redwoods software development. Dan Flickinger, as the main developer of the ERG, has been an invaluable source of inspiration on the treebank design and has also been the main treebanker since Redwoods Second Growth. Chris Manning and Kristina Toutanova, and Stuart Shieber, as early adopters and consultants on the overall design of the resource and representations, have greatly influenced the evolution of the treebank and pioneered its use for stochastic parse selection. Ezra Callahan was the first annotator, constructing what has been released as the First Growth during a ten-week summer internship. John Beavers did the annotations of the new ecommerce sections. Francis Bond and his colleagues at the NTT Research Laboratory have been vigorous supporters, adapted the Redwoods approach for Japanese (dubbing their treebank Hinoki), and thus helped a lot in scaling up the technology. Marty Mayberry, Jason Baldridge, Alex Lascarides, and Miles Osborne, as active users of the ERG and Redwoods data, have provided crucial feedback on the representations and software and positively contributed to recent developments. Tim Baldwin, Emily M. Bender, Kathryn Campbell-Kibler, Ann Copestake, Andreas Eisele, Rob Malouf, Rebecca Neil, Ivan Sag, Erik Velldal, and Tom Wasow have all helped through advice and productive critique in various stages of the project.

The development of the Redwoods treebank was financed opportunistically from numerous sources, including multiple donations to CSLI from YY Technologies (Mountain View, CA), a CSLI Seeding Grant, the Stanford Symbolic Systems Program (through multiple sponsored summer internships), the Commission of the European Community (through the Deep-Thought project), Scottish Enterprise (through the ROSIE project), Nippon Telegraph and Telephone Corporation (NTT) (through a sponsored research contract to the LinGO Laboratory), and the Norwegian LOGON Initiative (through financial support to Dan Flickinger and Stephan Oepen).

RedwoodsTop (last edited 2011-10-20 11:08:04 by DanFlickinger)

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