Both the Handle and the DOI are systems of identification of digital objects that allow to assign one PURL ("persistent uniform resource locator") to electronic documents (books, magazine articles, congresses, teaching materials, etc.).

The Digital Object Identifier (DOI) is a unique and permanent identifier for electronic publications that provides information on the description of digital objects (magazines, articles, etc.), as well as its location on the Internet (using the corresponding metadata).

Unlike the URL system of the web pages, the DOI system It does not change over time although the article is relocated to a different address. The reason for this permanence is the incorporation of all the information affected in the form of metadata.

The DOI is primarily assigned to articles in electronic journals, but also to books, book chapters, conference communications, videos and other digital objects.

The main benefits of the DOI are:

• Find and locate a document in the network, guaranteeing its availability totally. For example, search engines can be used CrossRef and from DOI Foundation.
• Citation and publication of scientific documents or resources.
• Sharing information.
• Navigate to publications transparently.

The DOI is an alphanumeric code, based on the NISO Z39.84 norm, DOI Syntax, which presents the following structure:

• DOI directory: http://doi.org
• Prefix, to identify the University. The prefix for the UPC is 10.5821
• separator "/"
• suffix, to identify the digital object. Flexible structure established by the DOI manager.

Examples: http://doi.org/10.1000/182

The main advantages offered by the identification of scientific publications through a DOI are:

• Guarantee of a direct and permanent access to the electronic resource
• Increase in the visibility of scientific publications (with the associated increase in citations)
• Identification of the intellectual property of an electronic resource, thanks to the information associated with the corresponding metadata
• Interoperability with other platforms, repositories or search engines

Some recommendations related to the use of DOI are:

• The DOI of the document must always be displayed in the form of URLs and in link mode.
• Any change in the registered document must be updated in a centralized directory (change of location of the file, modifications of metadata, etc.).
• The DOI obtained in the bibliographical citations of articles and other publications of the University must be used.

The unit responsible for the management of the DOI in the UPC and Digital Polytechnic Initiative (IDP), management that presents the following characteristics:

• The DOI Registration Agency of the UPC and CrossRef.
• The current grant of the DOI is closely linked to the OJS platform of the University (Journals UPC).
• The IDP contact persons in charge of managing the DOI are:

• Jordi Prats: jordi.pratsupc.edu
• Fran Máñez: francisco.manezupc.edu