This page links to all available documentation and demos. The

Links

• There is a web demo and validator available (currently under development)
• A blog post (with Linked Data) about each known implementation can be found under the Category Implementations. Each implementation normally has a demo web service. For example the full Stanford Core NLP NIF output can be seen here:
  “My favorite actress is Natalie Portman!”
• Tutorials(for clients) can be found on this page, on the Tutorials & Challenges page.
• Reusable Java code is available as open source in the Google Code project. A readme file in the repository is explaining the basics.

Checklist

The checklist is separated in three parts. The first part states the minimal requirements, which allow basic interoperability. This allows for an initial low-effort integration. Then there is a further list for all requirements of NIF components. Note that there is a third list with things that are optional. Developers should look at this list especially, because it can help them to save some time. This list includes things, which might be provided by a central component or which just produce unnecessary triples.

Minimal requirements

The NIF wrapper …

1. takes text as input over some interface (CLI, Web Service, API )
2. has implemented the parameter prefix
3. produces well-formed RDF output (no syntax errors, N3 or RDF/XML recommended)
4. produces RDF with Offset Based URIs
5. fulfils the normative requirements in the Specification
6. fulfills the golden rule of conceptual interoperability

Remaining requirements

The NIF wrapper …

1. provides a web service and complies to the Web service requirements and parameters
2. has implemented the Context-hash Based URI recipe
3. can read NIF and load it into the internal data structure of the tool (e.g. read tokens for POS-Taggers or read POS-Tags from NIF for NER tools.)

Optional additions

1. the properties sso:nextWord, sso:nextSentence are just necessary for some use cases and should be omitted. The next/previous properties infer transitive properties, which increase reasoner work load.
2. the properties str:beginIndex, str:leftContext duplicate the information contained in the uris and can be included for easier search.
3. OLiA Classes and the hierarchy is copied as specified and included in the ourput.

Maven

Maven Dependencies

The Maven archiva with the libraries. (Currently 1.1-SNAPSHOT is recommended)
NIF Library and Ontology Bindings
Web Service

Maven Repository

<repository>
   <id>maven.aksw.internal</id>
   <name>University Leipzig, AKSW Maven2 Repository</name>
   <url>http://maven.aksw.org/repository/internal</url>
</repository>
<repository>
   <id>maven.aksw.snapshots</id>
   <name>University Leipzig, AKSW Maven2 Repository</name>
   <url>http://maven.aksw.org/repository/snapshots</url>
</repository>

Validation of NIF Models

OWL Validation

The basic OWL syntax can be validated efficiently with these standard tools:

• The OWL Validator
• The other OWL Validator
• Raptor RDF Syntax Library: for Ubuntu use sudo apt-get install libraptor2-0 and then rapper -i rdfxml myfile.owl
• Load the file in Protege and look at it