How to Handle Hierarchically Structured Resources Addressing Interoperability Issues in Digital Libraries

We present and describe the NEsted SeTs for Object hieRarchies (NESTOR) Framework that allows us to model, manage, access and exchange hierarchically structured resources. We envision this framework in the context of Digital Libraries and using it as a mean to address the complex and multiform concept of interoperability when dealing with hierarchical structures. The NESTOR Framework is based on three main components: The Model, the Algebra and a Prototype. We detail all these components and present a concrete use case based on archives that are collections of historical documents or records providing information about a place, institution, or group of people, because the archives are fundamental and challenging entities in the digital libraries panorama. Within the archives we show how an archive can be represented through set data models and how these models can be instantiated. We compared two instantiations of the NESTOR Model and show how interoperability issues can be addressed by exploiting the NESTOR Framework.