Quantities and Units Ontology

From the web sites:

The QUDT Ontologies, and derived XML Vocabularies, were developed by TopQuadrant and NASA at the NASA AMES Research Center (ARC). As part of the NExIOM (NASA Exploration Initiatives Ontology Models) project for the NASA Constellation Program, QUDT work started at NASA ARC in 2006. QUDT work has the goal of representing Systems of Units, Quantities and Systems of Types across all engineering and science disciplines for the lifecycle needs of aerospace engineering, across all disciplines.

The QUDT ontologies provide the following:

1. Multiple Systems of Units
2. Comprehensive Coverage of Quantities
3. Ontology Support for Units Conversion using Dimensions
4. Simple and Structured Data Types

Specific ontologies in progress include a foundation ontology, and ontologies of Dimensions, Units, and Base Quantities.