ixa-pipe-nerc is a multilingual Sequence Labeler for tasks such as Named Entity Recognition (NERC), Opinion Target Extraction (OTE) and SuperSense Tagging (SST). Current version is 1.6.0

ixa-pipe-nerc is part of IXA pipes, a multilingual set of NLP tools developed by the IXA NLP Group [http://ixa2.si.ehu.es/ixa-pipes].

Please go to [http://ixa2.si.ehu.es/ixa-pipes] for general information about the IXA pipes tools but also for official releases, including source code and binary packages for all the tools in the IXA pipes toolkit.

This document is intended to be the usage guide of ixa-pipe-nerc. If you really need to clone and install this repository instead of using the releases provided in [http://ixa2.si.ehu.es/ixa-pipes], please scroll down to the end of the document for the installation instructions.

NOTICE!!: ixa-pipe-nerc is now in Maven Central for easy access to its API.

1. Overview of ixa-pipe-nerc

• Available features
• NERC distributed models
• OTE distributed models

2. Usage of ixa-pipe-nerc

• NERC tagging
• Opinion Target Extraction (OTE)
• Server mode
• Training your own models
• Evaluation

3. API via Maven Dependency
4. Git installation

ixa-pipe-nerc provides:

• NERC for Basque, English, Spanish, Dutch, German and Italian. The named entity types are based on:
  • CONLL: LOCATION, MISC, ORGANIZATION and PERSON. See CoNLL 2002 and CoNLL 2003 for more information.
  • SONAR-1: for Dutch, six main types, including CoNLL types plus PRODUCT and EVENT.
  • Ancora: for Spanish, six main types, including CoNLL types plus DATE and NUMBER.
• Opinion Target Extraction (OTE) for English. The models are trained on the SemEval 2014 and 2015 datasets; ixa-pipe-nerc was the best system in SemEval 2015 OTE subtask within task 12.
• SuperSense Tagging (SST) for English. The models are trained on Semcor.

Every model is self-contained, that is, the prop files are not needed to use them. You will find for each model a properties file describing its training although it is not needed to run the model. Please see the traininParams.properties template file for all available training options and documentation.

We provide competitive models based on robust local features and exploiting unlabeled data via clustering features. The clustering features are based on Brown, Clark (2003) and Word2Vec clustering plus some gazetteers in some cases. To avoid duplication of efforts, we use and contribute to the API provided by the Apache OpenNLP project with our own custom developed features for each of the three tasks.

A description of every feature is provided in the trainParams.properties properties file distributed with ixa-pipe-nerc. As the training functionality is configured in properties files, please do check this document. For each model distributed, there is a prop file which describes the training of the model, as well as a log file which provides details about the evaluation and training process.

Every result in reported here can be reproduced using the evaluation functionality of ixa-pipe-nerc or with the conlleval script using these scripts:

Reproducing results with conlleval: conlleval-results

NERC models:

• Release 1.5.4 [685MB]: nerc-models-latest.tgz

Every model is trained with the averaged Perceptron algorithm as described in (Collins 2002) and as implemented in Apache OpenNLP.

• Basque: eu-clusters model, trained on egunkaria dataset, F1 76.72 on 3 class evaluation and F1 75.40 on 4 classes.

• English Models:

  • CoNLL 2003 models: We distribute models trained with local features and with external knowledge. Each of the models improve in F1 (reported on testb data) but they get somewhat slower:

    • CoNLL 2003 local + brown features: F1 88.50
    • CoNLL 2003 local + clark features: F1 88.97
    • CoNLL 2003 light clusters model: F1 90.27
    • CoNLL 2003 clusters model: F1 90.82
    • CoNLL 2003 clusters + dicts: F1 91.19

  • Combined models: trained using Ontonotes 4.0, conll03 and muc 7 data, good for out of domain usage.

• Spanish Models:

  • CoNLL 2002 clusters: F1 84.16
  • CoNLL 2002 clusters + dict: F1 84.30

• Dutch Models:

  • CoNLL 2002 clusters: F1 84.23
  • CoNLL 2002 clusters + dict: F1 84.91

• German Models:

  • CoNLL 2003 clusters + dict: F1 76.42

• Italian Models:

  • Evalita09 clusters: F1 80.38

• Latest models: ote-models-latest

• English Models:

  • Trained on SemEval 2014 restaurants dataset.
  • Trained on SemEval 2015 restaurants dataset (ote subtask winner).

ixa-pipe-nerc provides a runable jar with the following command-line basic functionalities:

1. server: starts a TCP service loading the model and required resources.
2. client: sends a NAF document to a running TCP server.
3. tag: reads a NAF document containing wf and term elements and tags named entities.
4. ote: reads a NAF document containing wf and term elements and performs opinion target extraction (OTE).
5. train: trains new models for NERC, OTE and SST with several options available.
6. eval: evaluates a trained model with a given test set.
7. cross: it performs cross validation on a corpus.

Each of these functionalities are accessible by adding (server|client|tag|ote|train|eval|cross) as a subcommand to ixa-pipe-nerc-${version}-exec.jar. Please read below and check the -help parameter:

java -jar target/ixa-pipe-nerc-${version}-exec.jar (tag|ote|train|eval|cross) -help

Every option for training is documented in the trainParams.properties file distributed with ixa-pipe-nerc. Please do read that file!!

If you are in hurry, just execute:

cat file.txt | ixa-pipe-tok | ixa-pipe-pos | java -jar $PATH/target/ixa-pipe-nerc-${version}-exec.jar tag -m model.bin

If you want to know more, please follow reading.

ixa-pipe-nerc reads NAF documents (with wf and term elements) via standard input and outputs NAF through standard output. The NAF format specification is here:

(http://wordpress.let.vupr.nl/naf/)

You can get the necessary input for ixa-pipe-nerc by piping ixa-pipe-tok and ixa-pipe-pos as shown in the example.

There are several options to tag with ixa-pipe-nerc:

• model: pass the model as a parameter.
• language: pass the language as a parameter.
• outputFormat: Output annotation in a format: available CoNLL03, CoNLL02, OpenNLP native format and NAF. It defaults to NAF.
• lexer: switches on the rule-based DFA for NERC tagging. Currently we only provide one option numeric, which identifies "numeric entities" such as DATE, TIME, MONEY and PERCENT for all the languages currently in ixa-pipe-nerc.
• dictTag: directly tag named entities contained in a gazetteer.
  • tag: with tag option, only dictionary entities are annotated.
  • post: with post option, the output of the statistical model is post-processed.
• dictPath: the directory containing the gazetteers for the --dictTag option.

Example:

cat file.txt | ixa-pipe-tok | ixa-pipe-pos | java -jar $PATH/target/ixa-pipe-nerc-${version}-exec.jar tag -m nerc-models-$version/en/en-local-conll03.bin

As for NER tagging, the ote requires an input NAF with wf and term elements:

cat file.txt | ixa-pipe-tok | ixa-pipe-pos | java -jar $PATH/target/ixa-pipe-nerc-${version}-exec.jar ote -m model.bin

ixa-pipe-nerc reads NAF documents (with wf and term elements) via standard input and outputs opinion targets in NAF through standard output. The NAF format specification is here:

(http://wordpress.let.vupr.nl/naf/)

You can get the necessary input for ixa-pipe-nerc by piping ixa-pipe-tok and ixa-pipe-pos as shown in the example.

There are several options to tag with ixa-pipe-nerc:

• model: pass the model as a parameter.
• language: pass the language as a parameter.
• outputFormat: Output annotation in a format: available OpenNLP native format and NAF. It defaults to NAF.

Example:

cat file.txt | ixa-pipe-tok | ixa-pipe-pos | java -jar $PATH/target/ixa-pipe-nerc-${version}-exec.jar ote -m ote-models-$version/en/ote-semeval2014-restaurants.bin

We can start the TCP server as follows:

java -jar target/ixa-pipe-nerc-${version}-exec.jar server -l en --port 2060 -m en-91-18-conll03.bin

Once the server is running we can send NAF documents containing (at least) the term layer like this:

 cat file.pos.naf | java -jar target/ixa-pipe-nerc-${version}-exec.jar client -p 2060

To train a new model for NERC, OTE or SST, you just need to pass a training parameters file as an argument. As it has been already said, the options are documented in the template trainParams.properties file.

Example:

java -jar target/ixa.pipe.nerc-$version.jar train -p trainParams.properties

Training with Features using External Resources: For training with dictionary or clustering based features (Brown, Clark and Word2Vec) you need to pass the lexicon as value of the respective feature in the prop file. This is only for training, as for tagging or evaluation the model is serialized with all resources included.

You can evaluate a trained model or a prediction data against a reference data or testset.

• language: provide the language.
• model: if evaluating a model, pass the model.
• testset: the testset or reference set.
• corpusFormat: the format of the reference set and of the prediction set if --prediction option is chosen.
• prediction: evaluate against a prediction corpus instead of against a model.
• evalReport: detail of the evaluation report
  • brief: just the F1, precision and recall scores
  • detailed, the F1, precision and recall per class
  • error: the list of false positives and negatives

Example:

java -jar target/ixa.pipe.nerc-$version.jar eval -m nerc-models-$version/en/en-local-conll03.bin -l en -t conll03.testb

The easiest way to use ixa-pipe-nerc programatically is via Apache Maven. Add this dependency to your pom.xml:

<dependency>
    <groupId>eus.ixa</groupId>
    <artifactId>ixa-pipe-nerc</artifactId>
    <version>1.6.0</version>
</dependency>

The javadoc of the module is located here:

ixa-pipe-nerc/target/ixa-pipe-nerc-$version-javadoc.jar

The contents of the module are the following:

+ formatter.xml           Apache OpenNLP code formatter for Eclipse SDK
+ pom.xml                 maven pom file which deals with everything related to compilation and execution of the module
+ src/                    java source code of the module and required resources
+ Furthermore, the installation process, as described in the README.md, will generate another directory:
target/                 it contains binary executable and other directories
+ trainParams.properties      A template properties file containing documention
for every available option

Installing the ixa-pipe-nerc requires the following steps:

If you already have installed in your machine the Java 1.7+ and MAVEN 3, please go to step 3 directly. Otherwise, follow these steps:

If you do not install JDK 1.7+ in a default location, you will probably need to configure the PATH in .bashrc or .bash_profile:

export JAVA_HOME=/yourpath/local/java7
export PATH=${JAVA_HOME}/bin:${PATH}

If you use tcsh you will need to specify it in your .login as follows:

setenv JAVA_HOME /usr/java/java17
setenv PATH ${JAVA_HOME}/bin:${PATH}

If you re-login into your shell and run the command

java -version

You should now see that your JDK is 1.7 or 1.8.

Download MAVEN 3 from

wget http://apache.rediris.es/maven/maven-3/3.0.5/binaries/apache-maven-3.0.5-bin.tar.gz

Now you need to configure the PATH. For Bash Shell:

export MAVEN_HOME=/home/ragerri/local/apache-maven-3.0.5
export PATH=${MAVEN_HOME}/bin:${PATH}

For tcsh shell:

setenv MAVEN3_HOME ~/local/apache-maven-3.0.5
setenv PATH ${MAVEN3}/bin:{PATH}

If you re-login into your shell and run the command

mvn -version

You should see reference to the MAVEN version you have just installed plus the JDK that is using.

If you must get the module source code from here do this:

git clone https://github.com/ixa-ehu/ixa-pipe-nerc

Execute this command to compile ixa-pipe-nerc:

cd ixa-pipe-nerc
mvn clean package

This step will create a directory called target/ which contains various directories and files. Most importantly, there you will find the module executable:

ixa-pipe-nerc-${version}-exec.jar

This executable contains every dependency the module needs, so it is completely portable as long as you have a JVM 1.7 installed.

To install the module in the local maven repository, usually located in ~/.m2/, execute:

mvn clean install

Rodrigo Agerri
IXA NLP Group
University of the Basque Country (UPV/EHU)
E-20018 Donostia-San Sebastián
rodrigo.agerri@ehu.eus