SUTime is a library for recognizing and normalizing time expressions. SUTime is available as part of the Stanford CoreNLP pipeline and can be used to annotate documents with temporal information. It is a deterministic rule-based system designed for extensibility.
SUTime was developed using TokensRegex, a generic framework for defining patterns over text and mapping to semantic objects. An included set of PowerPoint slides and the javadoc for SUTime provide an overview of this package.
SUTime annotations are provided automatically with the Stanford CoreNLP pipeline by including the
nerannotator. When a time expression is identified, theNamedEntityTagAnnotationis set with one of four temporal types (DATE,TIME,DURATION, andSET) and theNormalizedNamedEntityTagAnnotationis set to the value of the normalized temporal expression. The temporal type and value correspond to the TIMEX3 standard for type and value. (Note the slightly weird and non-specific entity nameSET, which refers to a set of times, such as a recurring event.)
using java.util;
using java.io;
using edu.stanford.nlp.pipeline;
using edu.stanford.nlp.tagger.maxent;
using edu.stanford.nlp.time;
using edu.stanford.nlp.util;
using edu.stanford.nlp.ling;
using Console = System.Console;
class Program
{
private static void Main()
{
// Path to the folder with models extracted from `stanford-corenlp-4.5.0-models.jar`
var jarRoot = @"..\..\..\..\data\paket-files\nlp.stanford.edu\stanford-corenlp-4.5.0\models";
var modelsDirectory = jarRoot + @"\edu\stanford\nlp\models";
// Annotation pipeline configuration
var pipeline = new AnnotationPipeline();
pipeline.addAnnotator(new TokenizerAnnotator(false));
pipeline.addAnnotator(new WordsToSentencesAnnotator(false));
// Loading POS Tagger and including them into pipeline
var tagger = new MaxentTagger(modelsDirectory +
@"\pos-tagger\english-left3words\english-left3words-distsim.tagger");
pipeline.addAnnotator(new POSTaggerAnnotator(tagger));
// SUTime configuration
var sutimeRules = modelsDirectory + @"\sutime\defs.sutime.txt,"
+ modelsDirectory + @"\sutime\english.holidays.sutime.txt,"
+ modelsDirectory + @"\sutime\english.sutime.txt";
var props = new Properties();
props.setProperty("sutime.rules", sutimeRules);
props.setProperty("sutime.binders", "0");
pipeline.addAnnotator(new TimeAnnotator("sutime", props));
// Sample text for time expression extraction
var text = "Three interesting dates are 18 Feb 1997, the 20th of july and 4 days from today.";
var annotation = new Annotation(text);
annotation.set(new CoreAnnotations.DocDateAnnotation().getClass(), "2013-07-14");
pipeline.annotate(annotation);
Console.WriteLine("{0}\n", annotation.get(new CoreAnnotations.TextAnnotation().getClass()));
var timexAnnsAll = annotation.get(new TimeAnnotations.TimexAnnotations().getClass()) as ArrayList;
foreach (CoreMap cm in timexAnnsAll)
{
var tokens = cm.get(new CoreAnnotations.TokensAnnotation().getClass()) as List;
var first = tokens.get(0);
var last = tokens.get(tokens.size() - 1);
var time = cm.get(new TimeExpression.Annotation().getClass()) as TimeExpression;
Console.WriteLine("{0} [from char offset {1} to {2}] --> {3}",
cm, first, last, time.getTemporal());
}
}
}