ContENER

Code for "Contextualized Embeddings in Named-Entity Recognition: An Empirical Study on Generalization", accepted as a short paper at ECIR 2020. (Link to the video presentation)

This code enables to compare the impact of BERT, ELMo, Flair and GloVe representations on NER generalization both to unseen mentions and out-of-domain.

Test entities are separated in 3 categories:

• Exact Match if they are in the training set in the exact same case sensitive form and tagged with the same type.
• Partial Match if at least one of their non stop words is in an entity of same type in the training set.
• New otherwise, i.e. if all their non stop words are unseen for this type.

Requirements

The code is written in Python 3.6 with the following main dependencies:

• Pytorch 1.3.1
• AllenNLP 0.8.2
• pytorch-pretrained-bert 0.6.1
• flair 0.4.1

Docker

A Dockerfile with the corresponding GPU environment and jupyterlab is provided in docker/

cd docker
nvidia-docker build -t contener -f Dockerfile_contener.gpu .
nvidia-docker run -it -p 8888:8888 -v <absolute_path>/:notebooks/ contener

Data Setup and Preprocessing

We experimented with the English versions of CoNLL03, OntoNotes 5.0 and WNUT 2017 datasets.

1) GloVe and ELMo embeddings

Run scripts/download_glove_and_elmo.sh to download GLoVe embeddings and ELMo 5.5B weights.

2) CoNLL03

You will need to find the eng.train, eng.testa and eng.testb files on your own.
Then place them in data/conll03/source/ and run scripts/preprocess_conll03.sh

3) WNUT 17

Simply run scripts/preprocess_wnut.sh to download and preprocess WNUT17.

4) OntoNotes 5.0

Download ontonotes-release-5.0_LDC2013T19.tgz from the LDC and place it in data/.
Then run scripts/preprocess_ontonotes.sh

Training

The results presented in the paper were obtained using the following configurations:

• embedder in glove, glove char, elmo, elmo_zero, flair, bert-large-fb (feature-based).
• encoder in bilstm, map
• decoder in crf

when running:

python train_ner.py -ds $dataset -emb $embedder -enc $encoder -dec $decoder -d 0.5 -bs 64 -ep 100 -p 5

Additionally:

• embedder can be bert-large for the finetuned version of BERT, bert-base or bert-base-fb, or any space separated list of embeddings that will be concatenated as in glove char.
• decoder can be softmax

Out-of-domain Evaluation

For out-of-domain evaluation, once training is complete for a given configuration, run:

python test_ood.py -ds $dataset -ood_ds $ood_dataset -emb $embedder -enc $encoder -dec $decoder

Reference

If you find any of this work useful, please cite our paper as follows:

@InProceedings{taille2020contextualized,
author="Taill{\'e}, Bruno and Guigue, Vincent and Gallinari, Patrick",
title="Contextualized Embeddings in Named-Entity Recognition: An Empirical Study on Generalization",
booktitle="Advances in Information Retrieval",
year="2020",
publisher="Springer International Publishing",
pages="383--391",
isbn="978-3-030-45442-5"
}