README.md

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CZERT

This repository keeps trained Czert-B-base-cased-long-zero-shot model for the paper Czert – Czech BERT-like Model for Language Representation For more information, see the paper

This is long version of Czert-B-base-cased created without any finetunning on long documents. Positional embedings were created by simply repeating the positional embeddings of the original Czert-B model

Available Models

You can download MLM & NSP only pretrained models CZERT-A-v1 CZERT-B-v1

After some additional experiments, we found out that the tokenizers config was exported wrongly. In Czert-B-v1, the tokenizer parameter "do_lower_case" was wrongly set to true. In Czert-A-v1 the parameter "strip_accents" was incorrectly set to true.

Both mistakes are repaired in v2. CZERT-A-v2 CZERT-B-v2

or choose from one of Finetuned Models

	Models
Sentiment Classification (Facebook or CSFD)	CZERT-A-sentiment-FB CZERT-B-sentiment-FB CZERT-A-sentiment-CSFD CZERT-B-sentiment-CSFD
Named Entity Recognition	CZERT-A-ner-CNEC CZERT-B-ner-CNEC PAV-ner-CNEC CZERT-A-ner-BSNLP CZERT-B-ner-BSNLP PAV-ner-BSNLP
Morphological Tagging	CZERT-A-morphtag-126k CZERT-B-morphtag-126k
Semantic Role Labelling	CZERT-A-srl CZERT-B-srl

How to Use CZERT?

Sentence Level Tasks

We evaluate our model on two sentence level tasks:

• Sentiment Classification,
• Semantic Text Similarity.

Document Level Tasks

We evaluate our model on one document level task

• Multi-label Document Classification.

Token Level Tasks

We evaluate our model on three token level tasks:

• Named Entity Recognition,
• Morphological Tagging,
• Semantic Role Labelling.

Downstream Tasks Fine-tuning Results

Sentiment Classification

	mBERT	SlavicBERT	ALBERT-r	Czert-A	Czert-B
FB	71.72 ± 0.91	73.87 ± 0.50	59.50 ± 0.47	72.47 ± 0.72	76.55 ± 0.14
CSFD	82.80 ± 0.14	82.51 ± 0.14	75.40 ± 0.18	79.58 ± 0.46	84.79 ± 0.26

Average F1 results for the Sentiment Classification task. For more information, see the paper.

Semantic Text Similarity

	mBERT	Pavlov	Albert-random	Czert-A	Czert-B
STA-CNA	83.335 ± 0.063	83.593 ± 0.050	43.184 ± 0.125	82.942 ± 0.106	84.345 ± 0.028
STS-SVOB-img	79.367 ± 0.486	79.900 ± 0.810	15.739 ± 2.992	79.444 ± 0.338	83.744 ± 0.395
STS-SVOB-hl	78.833 ± 0.296	76.996 ± 0.305	33.949 ± 1.807	75.089 ± 0.806	79.827 ± 0.469

Comparison of Pearson correlation achieved using pre-trained CZERT-A, CZERT-B, mBERT, Pavlov and randomly initialised Albert on semantic text similarity. For more information see the paper.

Multi-label Document Classification

	mBERT	SlavicBERT	ALBERT-r	Czert-A	Czert-B
AUROC	97.62 ± 0.08	97.80 ± 0.06	94.35 ± 0.13	97.49 ± 0.07	98.00 ± 0.04
F1	83.04 ± 0.16	84.08 ± 0.14	72.44 ± 0.22	82.27 ± 0.17	85.06 ± 0.11

Comparison of F1 and AUROC score achieved using pre-trained CZERT-A, CZERT-B, mBERT, Pavlov and randomly initialised Albert on multi-label document classification. For more information see the paper.

Morphological Tagging

	mBERT	Pavlov	Albert-random	Czert-A	Czert-B
Universal Dependencies	99.176 ± 0.006	99.211 ± 0.008	96.590 ± 0.096	98.713 ± 0.008	99.300 ± 0.009

Comparison of F1 score achieved using pre-trained CZERT-A, CZERT-B, mBERT, Pavlov and randomly initialised Albert on morphological tagging task. For more information see the paper.

Semantic Role Labelling

	mBERT	Pavlov	Albert-random	Czert-A	Czert-B	dep-based	gold-dep
span	78.547 ± 0.110	79.333 ± 0.080	51.365 ± 0.423	72.254 ± 0.172	81.861 ± 0.102	-	-
syntax	90.226 ± 0.224	90.492 ± 0.040	80.747 ± 0.131	80.319 ± 0.054	91.462 ± 0.062	85.19	89.52

SRL results – dep columns are evaluate with labelled F1 from CoNLL 2009 evaluation script, other columns are evaluated with span F1 score same as it was used for NER evaluation. For more information see the paper.

Named Entity Recognition

	mBERT	Pavlov	Albert-random	Czert-A	Czert-B
CNEC	86.225 ± 0.208	86.565 ± 0.198	34.635 ± 0.343	72.945 ± 0.227	86.274 ± 0.116
BSNLP 2019	84.006 ± 1.248	86.699 ± 0.370	19.773 ± 0.938	48.859 ± 0.605	86.729 ± 0.344

Comparison of f1 score achieved using pre-trained CZERT-A, CZERT-B, mBERT, Pavlov and randomly initialised Albert on named entity recognition task. For more information see the paper.

Licence

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. http://creativecommons.org/licenses/by-nc-sa/4.0/

How should I cite CZERT?

For now, please cite the Arxiv paper:

@article{sido2021czert,
      title={Czert -- Czech BERT-like Model for Language Representation}, 
      author={Jakub Sido and Ondřej Pražák and Pavel Přibáň and Jan Pašek and Michal Seják and Miloslav Konopík},
      year={2021},
      eprint={2103.13031},
      archivePrefix={arXiv},
      primaryClass={cs.CL},
      journal={arXiv preprint arXiv:2103.13031},
}