| ==================================================== | |
| CoNLL-2014 Shared Task: Grammatical Error Correction | |
| Description of Preprocessed NUCLE Data Set | |
| 7 April 2014 Version 3.2 | |
| ==================================================== | |
| 1. General | |
| ========== | |
| This README file describes a preprocessed version of the NUS Corpus of | |
| Learner English (NUCLE). For information about NUCLE, please refer to | |
| the NUCLE README file. For information about the CoNLL-2014 shared | |
| task, please refer to the shared task website. | |
| The preprocessed data set, following earlier CoNLL shared tasks, | |
| provides syntactic information for the raw texts in NUCLE. For each | |
| sentence, the part of speech tags, dependency parse tree, and | |
| constituent parse tree are encoded in a column format. | |
| In NUCLE, annotations are made at the character level, which means | |
| both the start offset and the end offset of an error annotation are | |
| character positions in the corresponding paragraph. In this | |
| preprocessed version, annotations are made at the token level, which | |
| means the start offset and the end offset are indexes of tokens in the | |
| corresponding sentence. | |
| This README is updated on 4 August 2014. | |
| 2. Files | |
| ======== | |
| Two files are to be generated: | |
| conll14st-preprocessed.conll | |
| conll14st-preprocessed.conll.ann | |
| conll14st-preprocessed.conll contains the preprocessed data in | |
| CoNLL-style column format. This file is not included in this | |
| distribution due to the size. | |
| conll14st-preprocessed.conll.ann contains token-level annotations. | |
| 3. Preprocessing systems | |
| ======================== | |
| The NUCLE corpus is preprocessed with the following steps to generate | |
| this preprocessed data set: | |
| a). sentence splitting, using nltk punkt [1]. | |
| Note: the version used to generate the files is before the fixing | |
| of issue 514 | |
| b). word tokenization, using nltk word_tokenize [1]. | |
| c). POS tags, dependency parse trees, and constituent parse trees, | |
| using the Stanford parser [2]. | |
| d). projecting character-level annotation to token-level annotation. | |
| Results from (a-c) are in conll14st-preprocessed.conll. The projected | |
| annotations (d) are included in conll14st-preprocessed.conll.ann. | |
| 4. Data format | |
| ============== | |
| Here is an example sentence in conll14st-preprocessed.conll: | |
| NID PID SID TOKENID TOKEN POS DPHEAD DPREL SYNT | |
| 829 1 2 0 This DT 1 det (ROOT(S(NP* | |
| 829 1 2 1 will NN 7 nsubj *) | |
| 829 1 2 2 , , - - * | |
| 829 1 2 3 if IN 4 mark (SBAR* | |
| 829 1 2 4 not RB 7 dep (FRAG* | |
| 829 1 2 5 already RB 4 dep (ADVP*))) | |
| 829 1 2 6 , , - - * | |
| 829 1 2 7 caused VBD -1 root (VP* | |
| 829 1 2 8 problems NNS 7 dobj (NP*) | |
| 829 1 2 9 as IN 11 mark (SBAR* | |
| 829 1 2 10 there EX 11 expl (S(NP*) | |
| 829 1 2 11 are VBP 7 advcl (VP* | |
| 829 1 2 12 very RB 13 advmod (NP(NP(ADJP* | |
| 829 1 2 13 limited VBN 14 amod *) | |
| 829 1 2 14 spaces NNS 11 nsubj *) | |
| 829 1 2 15 for IN 14 prep (PP* | |
| 829 1 2 16 us PRP 15 pobj (NP*))))))) | |
| 829 1 2 17 . . - - *)) | |
| The columns represent the following: | |
| Column Type Description | |
| 0 NID Document id of the sentence, equals to "nid" in NUCLE. | |
| 1 PID Paragraph index of the sentence, according to the paragraphing in NUCLE (<p></p>). | |
| 2 SID Sentence index in paragraph, each sentence has its own index starting from 0. | |
| 3 TOKENID Token index in the sentence, starting from 0. | |
| 4 TOKEN Word/token. | |
| 5 POS Part of speech tag. | |
| 6 DPHEAD Index of parent in dependency tree. | |
| 7 DPREL Dependency relation with parent. | |
| 8 SYNT Constituent tree. The constituent tree can be recovered as follows: | |
| (a) Replacing "*" in this column with a string "(pos word)", | |
| where pos is the value of column 5, word is the value of column 4. | |
| (b) Concatenating all the strings in (a) gives | |
| the bracketing structure of the constituent parse tree. | |
| ------------------------------------------------------------------------ | |
| Here is the corresponding token-level annotation for the above | |
| sentence (in conll14st-preprocessed.conll.ann): | |
| <ANNOTATION> | |
| <MISTAKE nid="829" pid="1" sid="2" start_token="7" end_token="8"> | |
| <TYPE>Vform</TYPE> | |
| <CORRECTION>cause</CORRECTION> | |
| </MISTAKE> | |
| <MISTAKE nid="829" pid="1" sid="2" start_token="14" end_token="15"> | |
| <TYPE>Nn</TYPE> | |
| <CORRECTION>space</CORRECTION> | |
| </MISTAKE> | |
| <MISTAKE nid="829" pid="1" sid="2" start_token="11" end_token="12"> | |
| <TYPE>SVA</TYPE> | |
| <CORRECTION>is</CORRECTION> | |
| </MISTAKE> | |
| </ANNOTATION> | |
| The tags represent the following: | |
| Tag Description | |
| <ANNOTATION> Each <ANNOTATION></ANNOTATION> section identifies annotations for one sentence. | |
| <MISTAKE> Identifies an error annotation, with the following attributes: | |
| nid: Document id of the sentence, equals to the NID column (column 0) in .conll file | |
| pid: Paragraph index of the sentence, equals to the PID column in .conll file | |
| sid: Sentence index in paragraph, equals to the SID column in .conll file | |
| start_token: The token index (TOKENID column in .conll file) which is the start of annotation. | |
| end_token: The token index which is the end of the annotation. | |
| <TYPE> Error tag (refer to the NUCLE corpus README file for the complete list of error tags). | |
| <CORRECTION> Correction, replacing tokens in the interval [start_token, end_token) with the | |
| correction string will result in a corrected sentence. | |
| ------------------------------------------------------------------------ | |
| How to map a sentence to its annotation? | |
| In conll14st-preprocessed.conll, different sentences are separated by | |
| empty lines, and <ANNOTATION></ANNOTATION> sections are also separated | |
| by empty lines in conll14st-preprocessed.conll.ann. A sentence maps | |
| to one <ANNOTATION></ANNOTATION> section, with the same nid, pid, and | |
| sid. If a sentence has no annotation, there is no | |
| <ANNOTATION></ANNOTATION> section for it. The order of the | |
| <ANNOTATION></ANNOTATION> sections is the same as the order of | |
| sentences in the preprocesed file. | |
| 5. Updates included in version 2.1 | |
| ================================== | |
| The error categories Wcip and Rloc have been mapped to Prep, Wci, | |
| ArtOrDet, and Rloc-, to facilitate the detection and correction of | |
| preposition errors and article/determiner errors. See the NUCLE README | |
| file for details on how the mapping was done. | |
| 50 overlapping error annotations involving the 5 error tags ArtOrDet, | |
| Prep, Nn, Vform, and SVA have been modified such that they do not | |
| overlap in the revised error annotations. | |
| Some minor mistakes in error annotations have been corrected. | |
| This was done for the CoNLL-2013 Shared Task. | |
| 6. Updates included in version 3.0 | |
| ================================== | |
| The overlapping error annotations of the remaining error tags have | |
| been modified such that they do not overlap in the revised error | |
| annotations. | |
| Some minor mistakes in error annotations have been corrected. | |
| 7. Updates included in version 3.1 | |
| ================================== | |
| Duplicate error annotations, each having the same span and correction | |
| string but different error type, are removed to keep only one of | |
| those. | |
| Previously, annotations spanning to the end of the paragraph was | |
| detected as cross-sentence and therefore not included in the | |
| preprocessed format. This has been fixed such that they are included | |
| in the preprocessed format. | |
| Some minor mistakes in error annotations have been corrected. | |
| 8. Updates included in version 3.2 | |
| ================================== | |
| The preprocessing script has been fixed such that gold edits that | |
| insert empty string are not included in the token-level gold edit and | |
| scorer answer files. | |
| 9. References | |
| ============= | |
| [1] Steven Bird, Ewan Klein, and Edward Loper. 2009. Natural Language | |
| Processing with Python. O'Reilly Media Inc. http://nltk.org/ | |
| [2] Dan Klein and Christopher D. Manning. 2003. Accurate Unlexicalized | |
| Parsing. Proceedings of the 41st Annual Meeting of the Association for | |
| Computational Linguistics, pp. 423-430. | |
| Stanford parser version 2.0.1. | |
| http://nlp.stanford.edu/software/stanford-parser-2012-03-09.tgz | |