Stratigraphic Named Entity Recognition with Stanford CoreNLP

Introduction

This project provides training data and instructions for building a model to do named entity recognition (NER) of geological properties, namely chronostratigraphy and rock formation names.

We include around 2500 sentences extracted from publications of the British Geological Survey, with technical terms from BGS Geochronostratigraphy vocabulary and its Lexicon of Named Rock Units annotated with a custom named entity type (CHRONOSTRAT and LEXICON respectively).

The dataset was prepared by Dr Ike N'kisi Orji, supervised in BGS by Rachel Heaven, during his Doctoral Training Programme co-funded by BGS (BGS University Funding Initiative no. S291) and Robert Gordon University (School of Computing Science and Digital Media). The labelled sentences were extracted from an earlier collection of annotated publications known at the time as Textbase, and now referred to as Textbase 2000. The model has been used in text mining the BGS archives and linking documents and metadata to entities in the BGS Linked Data vocabularies.

Running in docker

We provide a Dockerfile to build and run CoreNLP Server including the custom NER model. You can also (currently) pull a docker image from the Github Container Registry - Custom CoreNLP docker image. As of writing, the Github registry requires authentication with a Personal Access Token - please see authenticating with the Github Container Registry for detail; the short version is this:

• Create a Personal Access Token with rights to read:packages; once logged in, start at Developer Settings/Tokens

• Use the personal access token to docker login before pulling down the image:

 export CR_PAT=YOUR_TOKEN
 echo $CR_PAT | docker login docker.pkg.github.com -u USERNAME --password-stdin
 ...
 docker pull docker.pkg.github.com/britishgeologicalsurvey/geo-ner-model/corenlp:v0.3

The following will pull down the image if not present, and run CoreNLP Server in the background, on port 9000.

docker run -d -p 9000:9000 docker.pkg.github.com/britishgeologicalsurvey/geo-ner-model/corenlp:v0.3

Alternatively use docker-compose with the config file provided in this repository to do the same:

docker-composse up -d

The first query to the server is often slow while it loads the models, and subsequent queries should be much faster.

Building the model

Instructions and download information for the latest Stanford CoreNLP library to train a model are based on this data at https://nlp.stanford.edu/software/CRF-NER.html

Files

1. bgs.3class.geo-training-data.txt : Data used to train the NER model. Three classes it recognises are as follows.

   • LEXICON : Entities specified in the BGS Lexicon of Named Rock Units http://data.bgs.ac.uk/doc/Lexicon.html
   • CHRONOSTRAT: Entities in the BGS geochronology and chronostratigraphy http://data.bgs.ac.uk/doc/Geochronology.html
   • BIOZONE: A handful of a biozones identified in the training data. These are very few and the model is not expected to perform well on this class.

2. bgs.3class.geo-testing-data.txt : Testing data for the NER model. It contains 70 CHRONOSTRAT and 425 LEXICON entities making a total of 495 entities in about 594 sentences. There are no biozones in the testing data!

3. bgs.3class.geo-all-data.txt : Combines training and test data above. Training and testing data were generated from separate source so this is expected to generate an even better model.

4. bgs.3class.geo.prop : Properties file for building the NER model. Description of parameters are at https://nlp.stanford.edu/nlp/javadoc/javanlp/edu/stanford/nlp/ie/NERFeatureFactory.html

5. vocab.gaz.txt : List of terms from both vocabularies used. This is also used in generating the NER model as specified in bgs.3class.geo.prop.

Training

Train the NER model:

• wget http://nlp.stanford.edu/software/stanford-corenlp-full-2018-10-05.zip ; unzip stanford-corenlp-full-2018-10-05.zip

• Edit bgs.3class.geo.prop if needed to point trainFile to the training file and gazette to file specifying entity names (vocab.gaz.txt). Use of gazetter made very minimal impact in our testing (slightly improved for CHRONOSTRAT and worsened for LEXICON).

• Train the model: java -cp stanford-corenlp-full-2018-10-05/stanford-corenlp-3.9.2.jar edu.stanford.nlp.ie.crf.CRFClassifier -prop bgs.3class.geo.prop

• The default bgs.3class.geo.prop we have supplied here includes both the training and testing data for the CoreNLP model (combined into bgs.3class.geo-all-data.txt)

Test the NER model

Testing gives precision, recall and f-measure scores.

• java -cp stanford-corenlp-full-2018-10-05/stanford-corenlp-3.9.2.jar edu.stanford.nlp.ie.crf.CRFClassifier -loadClassifier bgs.3class.geo.crf.ser.gz -testFile bgs.3class.geo-testing-data.txt

Model Evaluation

Performance results obtained using the training, testing and properties files specified here are as follows.

Entity	Precision	Recall	F1	TP	FP	FN
CHRONOSTRAT	0.9722	1.0000	0.9859	70	2	0
LEXICON	0.8794	0.8753	0.8774 372	51	53
Totals	0.8929	0.8929	0.8929	442	53	53

Contributing

Contributors to this project, as part of the broader Geosemantics efforts within BGS, include:

• Ike N'kisi Orji
• Rachel Heaven
• Robert McIntosh
• Jo Walsh
• Simon Burden
• James Passmore
• Marcus Sen

We welcome any contributions, including improvements to the annotations training data and any associated code building on the trained model. We make this available in the format required by CoreNLP but have also translated it into the spacy training format, producing models with some success but not yet such good performance. Please contact us through this repository or via enquiries@bgs.ac.uk

Licence

The contents of this repository are made available under the Creative Commons Attribution-ShareAlike license. Copyright ©BGS/Robert Gordon University 2018

References

• BGS Geochronology Linked Data
• BGS Lexicon of Named Rock Units Linked Data
• BGS Publication Viewer