IVOA Recommendation: An IVOA Standard for Unified Content Descriptors Version 1.1

This document describes the current understanding of the IVOA controlled vocabulary for describing astronomical data quantities, called Unified Content Descriptors (UCDs). The present document defines a new standard (named UCD1+) improving the first generation of UCDs (hereafter UCD1). The basic idea is to adopt a new syntax and vocabulary requiring little effort for people to adapt softwares already using UCD1. This document also addresses the questions of maintenance and evolution of the UCD1+. Examples of use cases within the VO, and tools for using UCD1+ are also described

IVOA Recommendation: The UCD1+ controlled vocabulary Version 1.23

This document describes the list of controlled terms used to build the Unified Content Descriptors, Version 1+ (UCD1+). The document describing the UCD1+ can be found at the URL: http://www.ivoa.net/Documents/latest/UCD.html. This document reviews the structure of the UCD1+ and presents the current vocabulary

IVOA Recommendation: Vocabularies in the Virtual Observatory Version 1.19

This document specifies a standard format for vocabularies based on the W3C's Resource Description Framework (RDF) and Simple Knowledge Organization System (SKOS). By adopting a standard and simple format, the IVOA will permit different groups to create and maintain their own specialised vocabularies while letting the rest of the astronomical community access, use, and combine them. The use of current, open standards ensures that VO applications will be able to tap into resources of the growing semantic web. The document provides several examples of useful astronomical vocabularies

The UCD1+ controlled vocabulary Version 1.3 Version 1.3

This document describes the list of controlled terms used to build the Unified Content Descriptors, Version 1+ (UCD1+). The document describing the UCD1+ can be found at the URL: www.ivoa.net/Documents/latest/UCD.html. This document reviews the structure of the UCD1+ and presents the current vocabulary. This version contains new UCD words for the planetary data community as proposed in the Technical Note by Cecconi et al. [3]. The suggested list of line labels under the em.line branch is not included. A general solution is currently under study to deal with lists of element instances such spectral lines, chemical elements, elementary particles, etc. using either utypes or a vocabulary