The NLP Interchange Format (NIF) is an RDF/OWL-based format that aims to achieve interoperability between Natural Language Processing (NLP) tools, language resources and annotations. The core of NIF consists of a vocabulary, which can represent Strings as RDF resources. A special URI Design is used to pinpoint annotations to a part of a document. These URIs can then be used to attach arbitrary annotations to the respective character sequence. Employing these URIs, annotations can be published on the Web as Linked Data and interchanged between different NLP tools and applications.
In order to simplify the combination of tools, improve their interoperability and facilitating the use of Linked Data we developed the NLP Interchange Format (NIF). NIF addresses the interoperability problem on three layers: the structural, conceptual and access layer. NIF is based on a Linked Data enabled URI scheme for identifying elements in (hyper-) texts (structural layer) and a comprehensive ontology for describing common NLP terms and concepts (conceptual layer). NIF-aware applications will produce output (and possibly also consume input) adhering to the NIF ontology as REST services (access layer). Other than more centralized solutions such as UIMA and GATE, NIF enables the creation of heterogeneous, distributed and loosely coupled NLP applications, which use the Web as an integration platform. Another benefit is, that a NIF wrapper has to be only created once for a particular tool, but enables the tool to interoperate with a potentially large number of other
tools without additional adaptations. Ultimately, we envision an ecosystem of NLP tools and services to emerge using NIF for exchanging and integrating rich annotations.
We designed NIF to be very light-weight and to reduce the amount of triples to achieve better scalability. The following triples in N3 Syntax express that the string “W3C” on http://www.w3.org/DesignIssues/LinkedData.html (index 22849 to 22852) is linked to the DBpedia resource of “World_Wide_Web_Consortium”:
@prefix ld: <http://www.w3.org/DesignIssues/LinkedData.html#> .
@prefix str: <http://nlp2rdf.lod2.eu/schema/string/> .
@prefix dbo: <http://dbpedia.org/ontology/> .
@prefix scms: <http://ns.aksw.org/scms/> .
@prefix nerd: <http://nerd.eurecom.fr/ontology#> .
ld:offset_22849_22852_W3C str:anchorOf "W3C" .
ld:offset_22849_22852_W3C scms:means dbpedia:World_Wide_Web_Consortium .
ld:offset_22849_22852_W3C a dbo:Organisation , nerd:Organization .
NIF already incorporates the Ontologies of Linguistic Annotation (OLiA) and the Named Entity Recognition and Disambiguation (NERD) ontology. Please get in contact, if you know of further NLP ontologies, which we can reuse and integrate in NIF.
This release consists of the following items:
- The specification of NIF 1.0. This document will guide the further implementation of NIF-enabled services. An average wrapper requires around 200-500 lines of code. The spec integrates several domain ontologies (OLiA, NERD) and will be extended in the future to cover more domains.
- A community portal with a mailing list: firstname.lastname@example.org . Read how to get involved.
- A reference implementations of NIF 1.0 in Java
- Wrapper implementations for Stanford CoreNLP, SnowballStemmer, OpenNLP, MontyLingua, DBpedia Spotlight, UIMA, Gate (for ANNIE and also generic output), Mallet (alpha)
- Tutorials and Tutorial Challenges
- A technical report including some evaluation.
We would like to thank our colleagues from AKSW research group and the LOD2 project for their helpful comments and inspiring discussions during the development of NIF. Especially, we would like to thank Christian Chiarcos for his support while using OLiA, the members of the Working Group on Open Data in Linguistics and the students that participated in the NIF field study: Markus Ackermann, Martin Brümmer, Didier Cherix, Marcus Nitzschke, Robert Schulze.