Core Technologies for Ontologies
The use of ontologiesA type of relational controlled vocabulary, which provides for categories, relationships, rules and axioms among metadata elements. Typically a hierarchy of classes and terms, an ontology is a machine-readable way of relating metadata terminology. Related Guide for data interoperabilityThe ability of two or more information systems to exchange metadata with minimal loss of information. Related Guide and Semantic WebThe transformation of the web from an inherently human-interpretable medium to an inherently computer-interpretable medium. In the semantic web, machines can read and understand the content published in the network. technologies relies on a core set of standards developed by the World Wide Web Consortium (w3c). Using these standards, technology implementers everywhere can deploy solutions that work not only in their individual instanceA metadata document describing a resource in a standards-compliant manner For example, the Everglades Hydrology and Water Quality Data document provided in XML by the USGS. Also, see other MMI-provided metadata instance examples. but can work with software and data created and provided by others.
The core technologies that enable this are Extensible Markup Language (XMLeXtensible Markup Language ), Resource Description Framework (RDFResource Description Framework ), and the Web Ontology Language (OWLWeb Ontology Language ). Each of these plays a role in the creation, storage, and use of ontologies.
XML is the backbone of both RDF and OWL, as each of them are built on the extensible programming language platform that is the essence of XML. RDF provides a specialized extensionAddition to a metadata standard that allows users to provide information in additional fields, or additional ways, that were not mentioned in the original standard. Related Guide of XML that allows for the description of resources in ontologies using a standardized set of syntax.
OWL builds upon RDF by adding an ontological layer, meaning that the resources described by RDF are capable of being classified and defined by OWL.
In this section of the guide, we will introduce you to these core technologies and provide a brief description of each. In addition, we discuss how to store and access ontologies using several methods. We provide an overview of common software libraries that are used to work with ontologies and, finally, we discuss how computers can analyze ontologies to draw inferences using a specialized technology called inference or reasoning engines.