# About PIDA
PIDA is a free-of-charge PURL service developed and maintained by the Helmholtz Metadata Collaboration (HMC). We provide unique persistent URLs (PURLs) that can be used as internationalized resource identifiers (IRIs) within semantic artifacts such as glossaries, thesauri, ontologies and knowledge graphs.
With a PIDA PURL, you can ensure that your semantic artifact entities are reliably and unambiguously (opens new window) identified and referenced on the web.
# PIDA's main features
PIDA is similar to, but different from, common PURL services. We offer several unique additional features, such as:
# Content negotiation
PIDA supports content negotiation (opens new window) - a technology widely used by semantic web systems. Content negotiation means that PIDA can redirect to different representations (HTML, RDF or else) or serializations (for RDF, TTL, OWL or else) of a resource, from a given PIDA PURL. Content negotiation for your PIDA PURL is enabled by adding the required information and redirection rules to your .htaccess file (see also manage PURLs section).
# User support
Creating a PIDA PURL and the proper redirection rules for it, omes with a lot of options and the potential for hiccups. At PIDA you can get support: we counsel, review, and support the creation of .htaccess files according to your needs. Please check the manage PURLs section to learn more about how we can support you in getting a PIDA PURL.
# Secured communication
PIDA uses HTTPS communication protocol (opens new window) to protect the integrity and confidentiality of data between clients and the service. This is especially important for systems and applications that require high levels of security, for example, when managing datasets in the biomedical domain.
# Regular system health checks
We conduct weekly health checks of all registered PURLs. If the base URI of a PURL does not resolve properly, we analyse and learn it through our checks. The most recent health check results can be seen on our stats-dashoboard (opens new window).
# Automatic notification
When PURLs were detected to not work propperly during our health checks, a notification service is triggered. With this we notify the registrars about the artifact in question and at which point in time we registered problems. We ask registrars to fix the problem within an embargo period of 1 year. Should the problem persist, we reserve the right to remove the PURL from he PIDA system.
# Usage statistics
We log PIDA activity and usage statistics; this includes (A) registration of novel semantic artifacts in our system, and (B) redirection requests arriving in our system. This allows us to offer usage statistics on our stats-dashoboard (opens new window) about PIDA in total and your registered artifact specifically. Doing all this, we value your privacy: all recorded data is fully anonymized; we do not process or store IPs or any personal data.
# Persistent and reliable availability
PIDA is reliable and persistent! From v2.0.0 on, PIDA is deployed on sophisticated cloud infrastructure at Jülich Supercomputing Center (opens new window). The deployment architecture now includes fail-safes and backups to guarantee near 24/7 availability of the PIDA service. Further, we guarantee the maintenance of the PIDA for 10+ years according to availability criteria in the FAIR principles (opens new window) and the requirements of most funding agencies.
# Get in touch
We'd love to get feedback on how you use PIDA, or on which other features you might find interesting to be added to the service. Send an email or open an issue in our development repository (opens new window).
# Who are we?
PIDA is a service provided by Hub Information and the FAIR Data Commons of the Helmholtz Metadata Collaboration (HMC) (opens new window), an incubator platform of the Helmholtz Association within the framework of the Information and Data Science strategic initiative. It is developed, deployed and maintained by the Institute for Advanced Simulation - Materials Data Science and Informatics (IAS-9) (opens new window) of the Forschungszentrum Jülich GmbH. PIDA service was started in August 2022.
# Disclaimer
We do not assess or judge the quality of semantic artifact for which PURLs are registered in the PIDA system.
