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. NIF consists of specifications, ontologies and software, which are combined under the version identifier "2.0", but are versioned individually. This ontology is developed by the NLP2RDF project (http://nlp2rdf.org) and provided as part of NIF 2.0 under CC-BY license as well as Apache 2.0. The ontology contains seven core URIs (String, RFC5147String, Context, isString, referenceContext, beginIndex, endIndex) that provide the foundation to express NLP annotations effectively in RDF.
| Attributes | Values |
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| type
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| versionInfo
| - Versioning done on resource level. See https://github.com/NLP2RDF/ontologies/blob/master/nif-core/nif-core.ttl
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| comment
| - 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. NIF consists of specifications, ontologies and software, which are combined under the version identifier "2.0", but are versioned individually. This ontology is developed by the NLP2RDF project (http://nlp2rdf.org) and provided as part of NIF 2.0 under CC-BY license as well as Apache 2.0. The ontology contains seven core URIs (String, RFC5147String, Context, isString, referenceContext, beginIndex, endIndex) that provide the foundation to express NLP annotations effectively in RDF.
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| isDefinedBy
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| label
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| described by
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| Creator
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| Description
|  - For a more concise description about NIF, we refer the reader to the ISWC 2013 in Use paper: Integrating NLP using Linked Data by Sebastian Hellmann, Jens Lehmann, Sören Auer, and Martin Brümmer available a : http://svn.aksw.org/papers/2013/ISWC_NIF/public.p f Also the NLP2RDF project page (http://nlp2rdf.org) provides more general documentation and pointers.
The NIF 2.0 Core Ontology (http://persistence.uni-leipzig.org/nlp2rdf/ontologies/nif-core#) provides classes and properties to describe the relations between substrings, text, documents by assigning URIs to strings. These URIs can then be used as subjects in RDF triples and therefore they can be annotated easily. The NIF 2.0 Core Specification defines how such URIs are created and use : http://persistence.uni-leipzig.org/nlp2rdf/specification/core.ht l and it makes sense to read this document first, so you can understand the definitions in this ontology better.
The main class in this ontology is nif:String, which is the class of all words over the alphabet of Unicode characters (sometimes called Σ∗). We built NIF upon the Unicode Normalization Form C, as this follows the recommendation of the RDF standard for rdf:Literal. Indices are to be counted in code units as is common in most programming language and SPARQL engines ( see 17.4.3.2 STRLEN and 17.4.3.3 SUBS R on http://www.w3.org/TR/sparql11-que y/).
Each URI Scheme (nif:URIScheme) used to address strings is a subclass of nif:String and puts further restrictions over the syntax of the URIs. For example, instances of type nif:RFC5147String have to adhere to the Syntax and Semantics of RFC 5147 (http://tools.ietf.org/html/rfc5147). Users of NIF can create their own URI schemes by subclassing nif:String and providing documentation on the Web in the rdfs:comment field.
Another important subclass of nif:String is the nif:Context OWL class. This class is assigned to the whole string of the text (i.e. all characters). The purpose of an individual of this class is special, because the string of this individual is used to calculate the indices for all substrings. Therefore, all substrings have to have a relation nif:referenceContext pointing to an instance of nif:Context. Furthermore, the datatype property nif:isString can be used to include the reference text as a literal within the RDF as is required for the web service scenario. An example of NIF Core can be seen on the top left of the example Figure.
Additional Resources
The project also provides serveral additional resources:
* various NIF representations of corpora
* different demos for NIF Webservices and a NIF Web Service Combinator
* a validation service for NIF RDF documents
* a draft of a Stanbol Profile Specification
Please find references to these (and other) resources in the NIF Dashb ard: http://dashboard.nlp2rdf.aksw.org/
Feedbac
If you'd like to leave feedback, please open an issue on GitHub (https://github.com/NLP2RDF/ontologies/issues) and read the README (https://github.com/NLP2RDF/ontologies#readme) or write an email to the mailing ist: http://lists.informatik.uni-leipzig.de/mailman/listinfo/nlp2rdf
Versi ning process is explained ere: http://persistence.uni-leipzig.org/nlp2rdf/specification/version html Changelog is written to rdfs:comment (resource level versioning).
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| Publisher
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| Title
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| Contributor
| - Martin Brümmer
- Navid Nourbakhsh
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| http://purl.org/vo...edNamespacePrefix
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| http://purl.org/vo...erredNamespaceUri
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| Rights
| - This ontology is licensed under Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0) and CC-BY (http://creativecommons.org/licenses/by/3.0/)
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| License
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| hasNamespacePrefix
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| http://purl.org/vocab/vann/changes
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| is topic
of | |
| is isDescribedUsing
of | |
| is about
of | |
![[RDF Data]](/fct/images/sw-rdf-blue.png)
