Abstract Meaning Representation (AMR) Annotation Release 2.0
Linguistic Data Consortium
1.0 Overview
This release comprises a sembank (semantic treebank) of 39260 English
natural language sentences. Each sentence is paired with an AMR graph
that represents its whole-sentence meaning in a tree-structure.
1.1 AMR Description
Meanings are encoded in Abstract Meaning Representation (AMR), a
language described in (Banarescu et al, 2013). AMR utilizes PropBank
frames, non-core semantic roles, within-sentence coreference, named
entity annotation, modality, negation, questions, quantities, and so
on to represent the semantic structure of a sentence largely
independent of its syntax.
More information about AMR, including annotation guidelines, can be
found at http://amr.isi.edu/language.html. Briefly:
(1) AMRs are rooted, labeled graphs. Like the Penn Treebank, AMRs
are written in a text format that is readable by people and
traversable by machines. As a simple example of the format, we
represent "the boy wants to go" as:
(w / want-01
:ARG0 (b / boy)
:ARG1 (g / go-02
:ARG0 b))
which can be paraphrased as: "There is a wanting event (w), whose
wanter is a boy (b), and whose wanted-thing is a going event (g).
The entity doing the going is the same boy (b)."
(2) AMR aims to abstract away from the syntactic structure of
English, frequently assigning the same AMR to different sentences
that mean the same thing:
(a / adjust-01
:ARG0 (b / girl)
:ARG1 (m / machine))
"The girl made adjustments to the machine."
"The girl adjusted the machine."
"The machine was adjusted by the girl."
(3) AMR incorporates entity recognition, co-reference, and semantic
roles, but adds significant amounts of further information required
to represent all of the contents of a sentence. This information
includes modality, negation, questions, non-core semantic relations
(e.g. purpose), event relations (e.g. enablement), inverse relations,
reification, etc.
(4) AMR makes extensive use of PropBank framesets (Kingsbury and
Palmer, 2002; Palmer et al., 2005), applying them beyond verbs. For
example, the phrase "bond investor" is represented with the frame
"invest-01", even though the phrase contains no verbs:
(p / person
:ARG0-of (i / invest-01
:ARG2 (b / bond))
(5) Single entities typically play multiple roles in an AMR. For
example, the AMR for "Pascale was charged with public intoxication
and resisting arrest" contains four instances of the variable "p":
(c / charge-05
:ARG1 (p / person
:name (n / name :op1 "Pascale"))
:ARG2 (a / and
:op1 (i / intoxicate-01
:ARG1 p
:location (p2 / public))
:op2 (r / resist-01
:ARG0 p
:ARG1 (a2 / arrest-01
:ARG1 p))))
Such multiple role-playing may represent English pronouns,
zero-pronouns, or control structures, but may also capture relations
that are implicit in text.
(6) AMR is agnostic about how to derive meanings from strings, and
vice-versa. In translating sentences to AMR, we do not dictate a
particular sequence of rule applications, or provide alignments that
reflect such rule sequences. This makes AMR annotation very fast,
and it allows researchers to explore their own ideas about how
strings are related to meanings.
(7) AMR is heavily biased towards English. It is not an Interlingua.
1.1 Major updates from previous AMR release (LDC2014T12)
(1) AMR Wikification
Named entities in AMR are now marked up with their :wiki values
where available, linking different surface terms such as "US" and
"United States of America" to the same entity "United_States".
Example:
English: US
AMR: (c / country :wiki "United_States"
:name (n / name :op1 "US"))
English: United States of America
AMR: (c / country :wiki "United_States"
:name (n / name :op1 "United" :op2 "States" :op3 "of" :op4 "America"))
When a named entity has no page on https://en.wikipedia.org/wiki
the wiki value is a hyphen-minus sign (:wiki "-").
(2) AMR Adoption of New Unified PropBank Frames
AMR has upgraded all of its old PropBank framesets to the current
PropBank version, which unifies frames across parts of speech,
e.g. it has the same frame for 'destroy' and 'destruction'.
(This unified approach has always been part of AMR's philosophy.)
See doc/PropBank-unification-notes.txt for more on the latest
PropBank version.
PropBank has grown in the number of framesets and in the number of
senses for a given lemma. AMR has already adopted many of these
additions and retrofitted AMR annotations to the new frames, but has
not done so for all new PropBank framesets, particularly not for new
non-verbal frames, such as "affair" and "(be) fond (of)". AMR will
continue to adopt new PropBank framesets and retrofit AMR annotations.
For some PropBank frames, the argument/role structure has changed.
There are some differences between the original PropBank at UColorado
and the version used for AMR:
AMR contains about 40 additional frames, including
-- role reification frames such as have-purpose-91 and
-- abstract frames such as have-org-role-91
that are not part of PropBank. These frames typically do not correspond
to specific lexical items on the English side.
(e.g. http://www.isi.edu/~ulf/amr/lib/amr-dict.html#have-org-role-91)
AMR does not include PropBank frames for words that are decomposable
such as 'undetectable', which in AMR is annotated using the frames
for 'possible' and 'detect':
(p / possible-01 :polarity - :ARG1 (d / detect-01)) or the inverted
(d / detect-01 :ARG1-of (p / possible-01 :polarity -))
AMR does not use PropBank roles created to handle discontinuous text
or separate syntactic nodes; AMR only uses true semantic roles.
Example:
(A) Bill Gates is believed to be rich.
(B) It is believed that Bill Gates is rich.
Original PropBank for (A):
arg1: Bill Gates
rel: believed
arg2: to be rich
AMR for both (A) and (B):
(b / believe-01
:ARG1 (r / rich
:domain (p / person :name (n / name :op1 "Bill" :op2 "Gates"))))
So AMR does not allow the original PropBank's :ARG2 under believe-01.
The PropBank frames included in this release are a snapshot of the
version used by AMR at the time of the release. The xml files'
slot-value pair 'usage="-AMR"' is used to indicate that the xml
component is not used by AMR, and 'usage="AMR"' is used to indicate
that the xml component is used only by AMR.
(3) AMR Deepening
AMR has deepened in a number of ways. For example:
-- Relational nouns such as 'brother', 'friend' and 'capital' are
now represented with a new abstract frame have-rel-role-91.
Example:
English: "my brother"
Old AMR: (b / brother :poss (i / i))
New AMR: (p / person
:ARG0-of (h / have-rel-role-91
:ARG1 (i / i)
:ARG2 (b / brother)))
(http://www.isi.edu/~ulf/amr/lib/amr-dict.html#have-rel-role-91)
-- Discourse frame instead-of-91 covers multiple English terms incl.
"instead of", "in place of", "as opposed to", and "not ... but".
(http://www.isi.edu/~ulf/amr/lib/amr-dict.html#instead-of-91)
(4) Automatic AMR-English Alignments
This release includes alignments automatically generated by an
AMR-English aligner written by Ulf Hermjakob (USC/ISI). These files
contain tokenized sentences (::tok instead of ::snt). The alignments
have not been checked by annotators; they are not gold.
Format info: doc/AMR-alignment-format.txt
(5) Correction of AMR Annotation Errors
The new version includes corrections of AMR annotation errors in the
previous versions. Any suspected additional AMR annotation errors
can be reported via http://amr.isi.edu/report-bug.html .
(6) XML
Some of the new sentences, especially Discussion Forum (dfb), contain
XML mark-ups such as " or ... or a.
The special frame hyperlink-91 is used to connect a URL to regular text.
2.0 Contents
2.1 Data Profile
The following table summarizes the number of training, dev, and test
AMRs for each dataset in the release. Totals are also provided by
partition and dataset:
Dataset Training Dev Test TOTALs
--------------------------------------------------------------
BOLT DF MT (bolt) 1061 133 133 1327
Broadcast conversation (cctv) 214 0 0 214
Weblog and WSJ (consensus) 0 100 100 200
BOLT DF English (dfa) 6455 210 229 6894
DEFT DF English (dfb) 19558 0 0 19558
Guidelines AMRs (guidelines) 819 0 0 819
2009 Open MT (mt09sdl) 204 0 0 204
Proxy reports (proxy) 6603 826 823 8252
Weblog (wb) 866 0 0 866
Xinhua MT (xinhua) 741 99 86 926
--------------------------------------------------------------
TOTALs 36521 1368 1371 39260
2.2 File Inventory
./data/amrs
Directory containing human-generated AMRs.
./data/amrs/split
For those interested in utilizing a standard/community partition for
AMR research (for instance in development of semantic parsers), this
directory contains 39260 AMRs split roughly 93%/3.5%/3.5% into
training/dev/test partitions, with most smaller datasets assigned to
one of the splits as a whole. Note that splits observe document
boundaries.
./data/amrs/split/dev
Directory containing 1368 dev-partitioned AMRs, across the following 5
dataset files. The number of AMRs in each text file is listed in
parentheses next to the file name:
amr-release-2.0-amrs-dev-bolt.txt (133)
amr-release-2.0-amrs-dev-consensus.txt (100)
amr-release-2.0-amrs-dev-dfa.txt (210)
amr-release-2.0-amrs-dev-proxy.txt (826)
amr-release-2.0-amrs-dev-xinhua.txt (99)
./data/amrs/split/test
Directory containing 1371 test-partitioned AMRs, across the following
5 dataset files. The number of AMRs in each text file is listed in
parentheses next to the file name:
amr-release-2.0-amrs-test-bolt.txt (133)
amr-release-2.0-amrs-test-consensus.txt (100)
amr-release-2.0-amrs-test-dfa.txt (229)
amr-release-2.0-amrs-test-proxy.txt (823)
amr-release-2.0-amrs-test-xinhua.txt (86)
./data/amrs/split/training
Directory containing 36521 training-partitioned AMRs, across the
following 9 dataset files. The number of AMRs in each text file is
listed in parentheses next to the file name:
amr-release-2.0-amrs-training-bolt.txt (1061)
amr-release-2.0-amrs-training-cctv.txt (214)
amr-release-2.0-amrs-training-dfa.txt (6455)
amr-release-2.0-amrs-training-dfb.txt (19558)
amr-release-2.0-amrs-training-guidelines.txt (819)
amr-release-2.0-amrs-training-mt09sdl.txt (204)
amr-release-2.0-amrs-training-proxy.txt (6603)
amr-release-2.0-amrs-training-wb.txt (866)
amr-release-2.0-amrs-training-xinhua.txt (741)
./data/amrs/unsplit
For those not interested in utilizing the training/dev/test AMR
partition, this directory contains the same 39260 AMRs unsplit
(i.e. with no training/dev/test partition), across the following 10
dataset files. The number of AMRs in each text file is listed in
parentheses next to the file name:
amr-release-2.0-amrs-bolt.txt (1327)
amr-release-2.0-amrs-cctv.txt (214)
amr-release-2.0-amrs-consensus.txt (200)
amr-release-2.0-amrs-dfa.txt (6894)
amr-release-2.0-amrs-dfb.txt (19558)
amr-release-2.0-amrs-guidelines.txt (819)
amr-release-2.0-amrs-mt09sdl.txt (204)
amr-release-2.0-amrs-proxy.txt (8252)
amr-release-2.0-amrs-wb.txt (866)
amr-release-2.0-amrs-xinhua.txt (926)
NOTE: The total number of ./data/amrs/unsplit files is 10, rather than
19, because all the amrs for each workset in the
./data/amrs/split/{dev,test,training} directories are combined into a
*single file* for each workset in in the ./data/amrs/unsplit
directory.
For example, the bolt dataset amrs files in the split directories:
amr-release-2.0-amrs-dev-bolt.txt
amr-release-2.0-amrs-test-bolt.txt
amr-release-2.0-amrs-training-bolt.txt
Are combined into a *single file* in the unsplit directory:
amr-release-2.0-amrs-bolt.txt
./data/alignments
Directory containing token-based alignments automatically generated by
an AMR-English aligner written by Ulf Hermjakob (USC/ISI). These files
contain tokenized sentences (::tok instead of ::snt). The alignments
have not been checked by annotators; they are not gold. Format info,
see AMR-alignment-format.txt in the ./docs directory
./data/alignments/split
This directory contains token-based alignments for 39260 AMRs split
into the training/dev/test partitions described above.
./data/alignments/split/dev
Directory containing token-based alignments for the same 1368
dev-partitioned AMRs described above, across a corresponding set of 5
alignment files.
./data/alignments/split/test
Directory containing token-based alignments for the same 1371
test-partitioned AMRs described above, across a corresponding set of 5
alignment files.
./data/alignments/split/training
Directory containing token-based alignments for the same 36521
training-partitioned AMRs described above, across a corresponding set
of 9 alignment files.
./data/alignments/unsplit
Directory containing token-based alignments for the same 39260 unsplit
AMRs (described above) across a corresponding set of 10 alignment
files.
./data/frames
Directory containing PropBank frames used to annotate the AMRs in this
release.
./data/frames/propbank-frames-xml-2016-03-08
Directory containing 5556 XML files for the PropBank frames used to
annotate the AMRs in this release.
./data/frames/propbank-frame-arg-descr.txt
Text file containing argument descriptions for the PropBank frames
files in the propbank-frames-xml-2016-03-08 directory.
./docs/AMR-alignment-format.txt
Text file describing the format of the token-based AMR-English
alignment files in the ./data/alignments directory.
./docs/PropBank-unification-notes.txt
Text file describing the new Unified (AMR-style) PropBank rolesets
used to produce the AMRs in this release.
./docs/amr-guidelines-v1.2.pdf
PDF files of the latest version of the guidelines under which the AMRs
in this release were produced.
./docs/frameset.dtd
DTD for validating the XML files in the
./data/frames/propbank-frames-xml-2016-03-08 directory
./docs/README.txt
This file.
2.3 Structure and content of individual AMRs
Each AMR-sentence pair in the ./data/amrs files comprises the
following data and fields:
- Header line containing a unique workset-sentence ID for the source
string that has been AMR annotated (::id), a completion timestamp
for the AMR (::date), an anonymized ID for the annotator who
produced the AMR (::annotator), and a marker for the AMRs of
dually-annotated sentences indicating whether the AMR is the
preferred representation for the sentence (::preferred)
- Header line containing the English source sentence that has been
AMR annotated (::snt)
- Header line indicating the date on which the AMR was last saved
(::save-date), and the file name for the AMR-sentence pair
(::file)
- Graph containing the manually generated AMR tree for the source
sentence (see the AMR guidelines for a full description of the
structure and semantics of AMR graphs).
NOTE: Proxy report AMRs have an additional field indicating the
sentence content type (date, country, topic, summary, body, or
body subordinate) (::snt-type)
NOTE: The presence of the field-value pair ":script
amr-snt-id-rep" indicates that the core header information for
that AMR was restored during processing (based on the filename and
workset for that AMR). It does not indicate any issues with the
AMR itself.
NOTE: AMR graphs may include quoted emoticons, and these may
include single parentheses, such as ":-)" or ":(". These graphs
will pass validation as long as they are parsed as lisp-like
source code, such that the quoted emoticon is escaped. If not, it
will appear that that parentheses in the graph are unbalanced.
3.0 Source data
The sentences that have been AMR annotated in this release are taken
from the following sources (their dataset shorthand appears in
parentheses).
3.1 BOLT Discussion forum MT data (bolt)
This discussion forum MT data comes from the Bolt Astral team's 2012p1
Tune dataset, and was selected for AMR annotation because it is rich
in informal language, expressions of sentiment and opinion, debates,
power dynamics, and a broader spectrum of events (e.g. communication
events) all of which are not typically found in traditional newswire
data. It also illustrates how AMR is applied to machine translation.
3.2 CCTV Broadcast conversation (cctv)
These transcripts and English translations of Mandarin Chinese
broadcast news conversation from China Central TV (CCTV) were selected
for AMR annotation as they contain a mixture of news content and
conversational features.
3.3 GALE Weblog and Wall Street Journal data (consensus)
This GALE weblog data in this dataset was selected for AMR annotation
because it contains informal language, as well as event phenomena of
interest to events researchers (e.g. causal relations, different
levels or granularities of events, irrealis events, fuzzy temporal
information, etc.)
The Wall Street Journal newswire data in this dataset was selected for
AMR annotation because these sentences contain an interesting
inventory of financial and economic events, and have been widely
annotated within the NLP community. Of the 200 sentences in this
dataset, 100 are from WSJ news, and 100 are GALE Weblog data.
3.4 BOLT Discussion forum English source data (dfa)
This discussion forum data was selected from from LDC's BOLT -
Selected & Segmented Source Data for Annotation R4 corpus (LDC2012R77)
for AMR annotation because it is rich in informal language,
expressions of sentiment and opinion, debates, power dynamics, and a
broader spectrum of events (e.g. communication events) all of which
are not typically found in traditional newswire data.
3.5 DEFT Discussion forum English source data (dfb)
This discussion forum data was selected from Multi-Post Discussion
Forum (MPDF) files collected by LDC, and were selected for AMR
annotation given their selection for annotation in other tasks (ERE,
BeSt, RED, etc) within the DARPA DEFT program. These selected MPDFs
included several high priority documents that were also chosen for
exploratory event annotation in DEFT.
NOTE: For purposes of AMR annotation, these MPDFs were automatically
segmented prior to production. Other DEFT tasks did *NOT* use this
segmentation, as they annotate at the document rather than sentence
level.
3.6 Guidelines AMR sentences (guidelines)
This data consists of constructed, example sentences that are used to
for AMR training, and which also appear in the
./docs/amr-guidelines-v1.2.pdf file. They were not selected from an
LDC dataset.
3.7 Open MT Data (mt09sdl)
This data was selected from the NIST 2008-2012 Open Machine
Translation (OpenMT) Progress Test Sets corpus (LDC2013T07) for AMR
annotation because it is rich in events and event-relations commonly
found in newswire data, and illustrates how AMR is applied to machine
translations.
3.8 Narrative text "Proxy Reports" from newswire data (proxy)
This data was selected and segmented from the proxy report data in
LDC's DEFT Narrative Text Source Data R1 corpus (LDC2013E19) for AMR
annotation because they are developed from and thus rich in events and
event-relations commonly found in newswire data, but also have a
templatic, report-like structure which is more difficult for machines
to process.
3.9 GALE-era Weblog data (wb)
The GALE-era weblog data in this dataset was selected for AMR
annotation because it contains informal language, as well as event
phenomena of interest to events researchers (e.g. causal relations,
different levels or granularities of events, irrealis events, fuzzy
temporal information, etc.)
3.10 Translated newswire data from Xinhua (xinhua)
This data was selected from LDC's English Chinese Translation Treebank
v 1.0 corpus (LDC2007T02) for AMR annotation because it is rich in
events and event-relations commonly found in newswire data, and
illustrates how AMR is applied to machine translation.
4.0 Annotation
Annotation for this AMR release was performed by over 25 annotators at
the University of Colorado, the Linguistic Data Consortium, and SDL.
4.1 Guidelines
The most-current version of the AMR guidelines can be found here:
4.2 The AMR Editor
All AMR annotation is carried out through a web-based editing tool
that encourages speed and consistency. This tool was built by Ulf
Hermjakob at USC/ISI. The AMR Editor:
1) Supports incremental AMR construction with rapid text-box
commands.
2) Highlights concepts that have PropBank framesets, displaying
those framesets with example sentences.
3) Pre-processes entities, dates, quantities, etc., making it easy
for annotators to cut and paste semantic fragments into their AMRs.
4) Provides annotation guidance, including lists of semantic
relations (with examples), named entity types, and a search function
that lets annotators query AMRs that were previously constructed by
themselves or others. Search queries may be words, phrases, or AMR
concepts.
5) Has a built-in AMR Checker that flags typical errors, such as
misspellings, omissions, illegal relations, etc.
6) Includes administrative support tools for user-account creation,
sharing of worksets, and annotator activity reports.
More details about the AMR Editor, including tutorial videos, can be
found at
#5.0 AMR Contributors
AMR was created by Kevin Knight and Ulf Hermjakob at USC Information
Sciences Institute (ISI), in collaboration with Daniel Marcu at SDL,
and Martha Palmer at University of Colorado. University of Colorado,
LDC, and SDL provide ongoing annotation resources and conceptual
collaboration that support development and distribution of AMR
corpora:
Principal AMR contributors:
Kevin Knight (USC/ISI), Ulf Hermjakob (USC/ISI), Kira Griffitt
(LDC), Martha Palmer (Univ. of Colorado), Claire Bonial (U.S. Army
Research Lab), Tim O'Gorman (Univ. of Colorado), Nathan Schneider
(Georgetown Univ.), Bianca Badarau (SDL), Madalina Bardocz (SDL)
PropBank frames:
Martha Palmer, Claire Bonial, Tim O'Gorman et al. at University of
Colorado Boulder
Support in AMR wikification:
Heng Ji, Xiaoman Pan et al. at Rensselaer Polytechnic Institute (RPI)
AMR annotation supervisors:
Ulf Hermjakob (USC/ISI), Bianca Badarau (SDL), Tim O'Gorman
(Univ. of Colorado), Kira Griffitt (LDC)
6.0 Acknowledgments
From University of Colorado
We gratefully acknowledge the support of the National Science
Foundation Grant NSF: 0910992 IIS:RI: Large: Collaborative Research:
Richer Representations for Machine Translation and the support of
Darpa BOLT - HR0011-11-C-0145 and DEFT - FA-8750-13-2-0045 via a
subcontract from LDC. Any opinions, findings, and conclusions or
recommendations expressed in this material are those of the authors
and do not necessarily reflect the views of the National Science
Foundation, DARPA or the US government.
From Information Sciences Institute (ISI)
Thanks to NSF (IIS-0908532) for funding the initial design of AMR, and
to DARPA MRP (FA-8750-09-C-0179) for supporting a group to construct
consensus annotations and the AMR Editor. The initial AMR bank was
built under DARPA DEFT FA-8750-13-2-0045 (PI: Stephanie Strassel;
co-PIs: Kevin Knight, Daniel Marcu, and Martha Palmer) and DARPA BOLT
HR0011-12-C-0014 (PI: Kevin Knight).
From Linguistic Data Consortium (LDC)
This material is based on research sponsored by Air Force Research
Laboratory and Defense Advance Research Projects Agency under
agreement number FA8750-13-2-0045. The U.S. Government is authorized
to reproduce and distribute reprints for Governmental purposes
notwithstanding any copyright notation thereon. The views and
conclusions contained herein are those of the authors and should not
be interpreted as necessarily representing the official policies or
endorsements, either expressed or implied, of Air Force Research
Laboratory and Defense Advanced Research Projects Agency or the
U.S. Government.
We gratefully acknowledge the support of Defense Advanced Research
Projects Agency (DARPA) Machine Reading Program under Air Force
Research Laboratory (AFRL) prime contract no. FA8750-09-C-0184
Subcontract 4400165821. Any opinions, findings, and conclusion or
recommendations expressed in this material are those of the author(s)
and do not necessarily reflect the view of the DARPA, AFRL, or the US
government.
From Language Weaver (SDL)
This work was partially sponsored by DARPA contract HR0011-11-C-0150
to LanguageWeaver Inc. Any opinions, findings, and conclusion or
recommendations expressed in this material are those of the author(s)
and do not necessarily reflect the view of the DARPA or the US
government.
7.0 AMR links
AMR website: http://amr.isi.edu
AMR public download page: http://amr.isi.edu/download.html (incl. resource lists)
AMR guidelines (overview): https://github.com/amrisi/amr-guidelines/blob/master/amr.md
AMR dictionary (details): http://amr.isi.edu/doc/amr-dict.html
AMR roles: http://amr.isi.edu/doc/roles.html
AMR quantity types: http://amr.isi.edu/doc/quantity-types.html
AMR named entity types: http://amr.isi.edu/doc/ne-types.html
AMR alignment guidelines: http://amr.isi.edu/doc/amr-alignment-guidelines.html
AMR annotation bug report: http://amr.isi.edu/report-bug.html
AMR tutorial https://github.com/nschneid/amr-tutorial
8.0 Copyright Information
Portions (c) 1987-1989 Dow Jones & Company, Inc., Portions (c) 2007
Agence France Presse, Al-Ahram, Al Hayat, Al-Quds Al-Arabi, Asharq
Al-Awsat, An Nahar, Assabah, China Military Online, Chinanews.com,
Guangming Daily, Xinhua News Agency, Portions (c) 2002-2005,
2007-2008 Agence France Presse, (c) 2002-2008 The Associated Press,
(c) 2003-2004, 2007-2008 Central News Agency (Taiwan), Portions (c)
1997, 2004-2007 China Central TV (CCTV), (c) 1995, 2003, 2007-2008
Los Angeles Times-Washington Post News Service, Inc., (c) 2002,
2004-2005, 2007-2008 New York Times, (c) 2001-2008 Xinhua News
Agency, Portions (c) 1994-1998 Xinhua News Agency
(c) 2016 Trustees of the University of Pennsylvania
9.0 Contact Information
For further information about this data release, contact the following
contributors:
Kevin Knight, ISI/USC
-- --
Bianca Badarau, SDL
Laura Baranescu, SDL
Claire Bonial, U.S. Army Research Lab
Madalina Bardocz, SDL
Kira Griffitt, LDC
Ulf Hermjakob, ISI/USC
Daniel Marcu, ISI/USC
Martha Palmer, Univ. of Colorado
Tim O'Gorman, Univ. of Colorado
Nathan Schneider, Georgetown Univ.
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README created by Kira Griffitt on August 1, 2016
README updated by Kira Griffitt on August 1, 2016
README updated by Kira Griffitt on August 4, 2016
README updated by Kira Griffitt on August 5, 2016
README updated by Kira Griffitt on August 16, 2016