The DOI System provides:
•an identification system of entities based on the Handle System, a globally distributed system for resolving identifiers
Any entity (digital, physical, or abstract) can be identified by a global unique and persistent identifier called a DOI name. The DOI name can be resolved to a resource, such as a web or internet resource, metadata describing the entity, a landing page with access to further resources, etc.
For example, a DOI name representing an article resolves to the web address of the HTML file version of the article.
•a metadata model based on the INDECS interoperable metadata framework
Metadata must be assigned to each DOI name to describe the entity represented by the DOI name. Metadata interoperability is ensured through basic principles outlined by the DOI Foundation.
Metadata is used to provide services to the users: it can be displayed to users to enrich an information resource; it can be used by users to search for a DOI name; etc.
The figure below illustrates the basic principle of the DOI System.
