Alignment API

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Alignment API

Name of the tool: Alignment API
Home page:
Date of latest release: 2014-01-22 (verify)
Programming language(s) that can be used with the tool: Java
Relevant semantic web technologies: RDF, RDFS, OWL, Alignment
Categories: API, Command Line Tool
See also:
Public mailing list:
Preferred project URI:
DOAP reference:
Company or institution: INRIA (Open source)

(Tool description last modified on 2014-03-26.)


The Alignment API is an API and implementation for expressing and sharing ontology alignments.

Using ontologies is the priviledged way to achieve interoperability among heterogeneous systems within the Semantic web. However, as the ontologies underlying two systems are not necessarily compatible, they may in turn need to be reconcilied. Ontology reconciliation requires most of the time to find the correspondences between entities (e.g., classes, objects, properties) occuring in the ontologies. We call a set of such correspondences an alignment. We have designed a format for expressing alignments in a uniform way. The goal of this format is to be able to share on the web the available alignments. The format is expressed in RDF, so it is freely extensible.

The Alignment API itself is a Java description of tools for accessing the common format. It defines five main interfaces (OntologyNetworks, Alignment, Cell, Relation and Evaluator) and proposes the following services:

  • Storing, finding, and sharing alignments;
  • Piping alignment algorithms (improving an existing alignment);
  • Manipulating (thresholding and hardening);
  • Generating processing output (transformations, axioms, rules);
  • Generating tests and comparing alignments (diff, precision, recall).