Integrating linked metadata repositories into the web of data

The heterogeneity of the environment in which data exchange happens is creating many challenges during the execution of digital public services across Europe. Lack of agreement and guidance on the meaning and format of information to be exchanged between Member States are the main stumbling block. Semantic interoperability is jeopardized by different interpretations of the information exchanged between people and applications, thus hampering the effective and efficient creation of new European public services. In an attempt to promote the use of common models and standards, governments develop e-Government metadata repositories to store semantic data models, taxonomies, codelists and reference data making them openly available for reuse. The term semantic asset has been devised to refer to these types of resources. However, these repositories differ in their scope, target group, implementation technologies and end-user interfaces. Although, the semantic content they include can often be reused, their physical isolation and the heterogeneity of the assets hamper the reusability of common concepts and cross-repository search. To deal with these challenges, this paper specifies a generic Exchange API that capitalizes on Linked Data technologies and REST in order to enable the semantic integration of distributed metadata repositories, thus creating a flexible federation which facilitates cross-repository querying and consequently enhances semantic asset reusability.