Flair中的英文命名实体识别（默认模型）

这是随 Flair 提供的英文标准四类命名实体识别模型。

F1得分：93.06（修正的CoNLL-03）

预测4个标签：

基于 Flair embeddings 和LSTM-CRF模型。

演示：如何在Flair中使用

所需工具： Flair （通过pip install flair安装）

from flair.data import Sentence
from flair.models import SequenceTagger

# load tagger
tagger = SequenceTagger.load("flair/ner-english")

# make example sentence
sentence = Sentence("George Washington went to Washington")

# predict NER tags
tagger.predict(sentence)

# print sentence
print(sentence)

# print predicted NER spans
print('The following NER tags are found:')
# iterate over entities and print
for entity in sentence.get_spans('ner'):
    print(entity)

运行该脚本会得到以下输出：

Span [1,2]: "George Washington"   [− Labels: PER (0.9968)]
Span [5]: "Washington"   [− Labels: LOC (0.9994)]

因此，在句子“George Washington went to Washington”中，存在实体“George Washington”（标记为人名）和“Washington”（标记为地名）。

训练：用于训练该模型的脚本

以下Flair脚本用于训练该模型：

from flair.data import Corpus
from flair.datasets import CONLL_03
from flair.embeddings import WordEmbeddings, StackedEmbeddings, FlairEmbeddings

# 1. get the corpus
corpus: Corpus = CONLL_03()

# 2. what tag do we want to predict?
tag_type = 'ner'

# 3. make the tag dictionary from the corpus
tag_dictionary = corpus.make_tag_dictionary(tag_type=tag_type)

# 4. initialize each embedding we use
embedding_types = [

    # GloVe embeddings
    WordEmbeddings('glove'),

    # contextual string embeddings, forward
    FlairEmbeddings('news-forward'),

    # contextual string embeddings, backward
    FlairEmbeddings('news-backward'),
]

# embedding stack consists of Flair and GloVe embeddings
embeddings = StackedEmbeddings(embeddings=embedding_types)

# 5. initialize sequence tagger
from flair.models import SequenceTagger

tagger = SequenceTagger(hidden_size=256,
                        embeddings=embeddings,
                        tag_dictionary=tag_dictionary,
                        tag_type=tag_type)

# 6. initialize trainer
from flair.trainers import ModelTrainer

trainer = ModelTrainer(tagger, corpus)

# 7. run training
trainer.train('resources/taggers/ner-english',
              train_with_dev=True,
              max_epochs=150)

引用

在使用该模型时，请引用以下论文。

@inproceedings{akbik2018coling,
  title={Contextual String Embeddings for Sequence Labeling},
  author={Akbik, Alan and Blythe, Duncan and Vollgraf, Roland},
  booktitle = {{COLING} 2018, 27th International Conference on Computational Linguistics},
  pages     = {1638--1649},
  year      = {2018}
}

问题？

Flair问题跟踪器可在 here 处找到。