The metadata interoperability platform MINT (http://mint.image.ntua.gr) is implementing aggregation workflows in the Europeana ecosystem. It was first introduced in the ATHENA project, that made circa 4 million items available to Europeana between 2008 and 2011. Central development continued, along with customised versions that facilitated several initiatives in the domain, including EUscreen, ECLAP, CARARE, DCA, Linked Heritage, PartagePlus and 3D-Icons. MINT currently supports several projects in the Europeana ecosystem such as Europeana Photography, Europeana Fashion, AthenaPlus, LoCloud, EUscreenXL and Europeana Sounds. The MINT group also contributes in various infrastructure, technology and policy projects such as Europeana Connect, Indicate, Europeana Awareness, Europeana Creative, Ambrosia and Europeana Space. Finally, it is in the core of the Europeana ingestion infrastructure that implements their internal aggregation and publication workflow, while it has contributed in the starting up of the Digital Public Library of America, having succeeded in the respective beta sprint and invited to present in the first and second plenary meetings.
In DM2E, MINT and D2R were introduced in order to kick off the aggregation tasks, before the development of the workflow management component and the respective user interface by work package 2. A dedicated MINT instance was setup, implementing the XSD for the DM2E model, based on the National Technical University of Athens (NTUA)’s implementation of EDM for Europeana. Dedicated training workshops instructed providers in the use of the visual mapping editor for the XSLT language, in order to create test mappings for XML or CSV imports that had to be translated to RDF. The two RDFizer tools and the SILK framework for contextualisation consisted the initial version of the project’s interoperability infrastructure.
With the design of the intermediate version of the infrastructure, MINT’s REST API was extended to expose the platform’s data and services, using the ontology that was introduced in the web-based engine for the specification, composition and execution of workflows. MINT also implemented a preprocessing step that improved the handling of records serialised in the MARC format and the subsequent use of the visual mapping editor. The preview services were also improved with the addition of a Europeana portal preview for EDM and a graph visualisation for RDF instances of the DM2E model. In parallel, an evaluation process led by work package 1 aimed at identifying the benefits and shortcomings of MINT when used with the various input models ingested by DM2E providers. Particularly, users were asked to evaluate the four basic aggregation steps; import, mapping creation, validation and XSLT export.
In general, MINT’s visual mapping functionality was accepted by the users. The concept was deemed very intuitive and helped users become familiar with the target data schema. The results of the evaluation pointed out that schemas which are not focused only at representing descriptive metadata, but also incorporate business processes or hierarchical representations of collections – such as EAD – are difficult to handle with the visual mapping editor, but could still benefit by creating a first version of the XSLT in MINT. Finally, users were able to identify some interesting aspects of working with that version of MINT that resulted in a set of bug fixes and improvements in the next release.
With the adoption of the single sign-on solution (JOSSO), MINT is fully integrated in the DM2E infrastructure, allowing the use of the mapping editor from the browser-based user interface (OmNom). For the final version of the infrastructure, two more MINT services are reused in order to assist providers and the work package 1 content team with improving the quality of publication, the Europeana HTML preview and, the validation service for the EDM model that uses the XSD and schematron rules.
Overall, the development, integration and evaluation processes resulted in productive discussions, continuously fine-tuned requirements and the evolution of both MINT and the interoperability infrastructure towards stable, intuitive tools for the execution of aggregation workflows for digital cultural heritage objects in the realm of digitised manuscripts.
Senior Researcher, National Technical University of Athens