OpenAIRE infrastructure sub-systems¶

The OpenAIRE infrastructure features a number of sub-systems, dedicated to four main activities:

• Aggregation sub-system: collection of information packages and publication texts (e.g. PDFs, XMLs, HTMLs) from data sources; based on the typology of such packages (e.g. Dublin Core metadata records, DataCite metadata records, CERIF-XML metadata records, proprietary formats), the system transforms them onto metadata records with uniform structure and semantics, matching the specification of the OpenAIRE data model;
• De-duplication sub-system: given as input the information space graph, the system identifies duplicates among the objects of the same entity type; for each entity, the system generates a set of similarity relationships between pairs of objects identified as duplicates, which can be used by the data publishing subsystem to generate a disambiguated information space;
• Information inference sub-system: given as input the last public information space graph (hence, disambiguated and enriched by inference in the last round) and the publications full-texts, the system applies a number of mining algorithms (i.e. "modules"); for each mining module the system produces a set (called ActionSet) of inferred concepts, which can be used by the data publishing sub-system to enrich the information space graph;
• Data provision sub-system: given as input the metadata records as yielded by the aggregation sub-system, the similarity relationships as (last) yielded by the de-duplication sub-system, and the inference ActionSets as (last) yielded by the information inference sub-system, the data provision system: 1) populates an initial bare-aggregation information space graph, 2) enriches the graph with similarity relationships and runs a object merging algorithm to remove duplicates, 3) enriches the graph with inferred information, 4) instantiates the graph over three back-ends: full-text index, OAI-PMH publisher, PostgreSQL statistics database (a LOD back-end is being developed in OpenAIRE2020).