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Dependency-Guided LSTM-CRF Model for Named Entity Recognition

Codebase for the upcoming paper "Dependency-Guided LSTM-CRF for Named Entity Recognition" in EMNLP 2019. The usage code below make sure you can reproduce almost same results as shown in the paper.

Requirements

• PyTorch 1.1 (Also tested on PyTorch 1.3)
• Python 3.6

Dataset Format

I have uploaded the preprocessed Catalan and Spanish datasets. (Please contact me with your license if you need the preprocessed OntoNotes dataset.) If you have a new dataset, please make sure we follow the CoNLL-X format and we put the entity label at the end. The sentence below is an example. Note that we only use the columns for word, dependency head index, dependency relation label and the last entity label.

1	Brasil	_	n	n	_	2	suj	_	_	B-org
2	buscará	_	v	v	_	0	root	_	_	O
3	a_partir_de	_	s	s	_	2	cc	_	_	O
4	mañana	_	n	n	_	3	sn	_	_	O
5	,	_	f	f	_	6	f	_	_	B-misc
6	viernes	_	w	w	_	4	sn	_	_	I-misc
7	,	_	f	f	_	6	f	_	_	I-misc
8	el	_	d	d	_	9	spec	_	_	O
9	pase	_	n	n	_	2	cd	_	_	O

Entity labels follow the IOB tagging scheme and will be converted to IOBES in this codebase.

Usage

Baseline BiLSTM-CRF:

python main.py --dataset ontonotes --embedding_file data/glove.6B.100d.txt \ 
               --num_lstm_layer 1 --dep_model none

Change embedding_file if you are using other languages, change dataset for other datasets, change num_lstm_layer for different L = 0,1,2,3. Use --device cuda:0 if you are using gpu.

DGLSTM-CRF

python main.py --dataset ontonotes --embedding_file data/glove.6B.100d.txt \ 
               --num_lstm_layer 1 --dep_model dglstm --inter_func mlp

Change the interaction function inter_func = concatenation, addition, mlp for other interactions.

Usage for other datasets and other languages

Remember to put the dataset under the data folder. The naming rule for train/dev/test is train.sd.conllx, dev.sd.conllx and test.sd.conllx. Then simply change the --dataset name and --embedding_file.

Using ELMo

In any case, once we have obtained the pretrained ELMo vector files ready. For example, download the Catalan ELMo vectors from here, decompressed all the files (train.conllx.elmo.vec,dev.conllx.elmo.vec, test.conllx.elmo.vec) into data/catalan/. We can then simply run the command below (we take the DGLSTM-CRF for example)

python main.py --dataset ontonotes --embedding_file data/glove.6B.100d.txt \ 
               --num_lstm_layer 1 --dep_model dglstm --inter_func mlp \
               --context_emb elmo

Obtain ELMo vectors for other languages:

We use the ELMo from AllenNLP for English, and use ELMoForManyLangs for other languages.

• English, run the preprocess/preelmo.py code (remember to change the dataset name)

  python preprocess/preelmo.py
  

• Chinese, Catalan, and Spanish Download the ELMo models from ELMoForManyLangs. NOTE: remember to follow the instruction to slighly modify some paths inside. Then you can run preprocess/elmo_others.py: (again remember to change dataset name and ELMo model path)

  python preprocess/elmo_others.py
  

Notes on Dataset Preprocessing (Two Options)

OntoNotes Preprocessing

Many people are asking for the OntoNotes 5.0 dataset. I understand that it is hard to get the correct split as in previous work (Chiu and Nichols, 2016; Li et al., 2017; Ghaddar and Langlais, 2018;). If you want to get the correct split, you can refere to a guide here where I summarize how to preprocess the OntoNotes dataset.

Download Our Preprocessed dataset

We notice that the OntoNotes 5.0 dataset has been freely available on LDC. We will also release our link to our pre-processed OntoNotes here (English, Chinese).

Citation

@InProceedings{jie2019dependency, 
    author = "Jie, Zhanming and Lu, Wei", 
    title = "Dependency-Guided LSTM-CRF for Named Entity Recognition", 
    booktitle = "Proceedings of EMNLP", 
    year = "2019",
    url = "https://www.aclweb.org/anthology/D19-1399",
    doi = "10.18653/v1/D19-1399",
    pages = "3860--3870"
}