The NESTOR Framework: how to Handle Hierarchical Data Structures

Περιέχει το πλήρες κείμενοIn this paper we study the problem of representing, managing and exchanging hierarchically structured data in the context of a Digital Library (DL). We present the NEsted SeTs for Object hieRarchies (NESTOR) framework defining two set data models that we call: the “Nested Set Model (NS-M)” and the “Inverse Nested Set Model (INSM)” based on the organization of nested sets which enable the representation of hierarchical data structures. We present the mapping between the tree data structure to NS-M and to INS-M. Furthermore, we shall show how these set data models can be used in conjunction with Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) adding new functionalities to the protocol without any change to its basic functioning. At the end we shall present how the couple OAI-PMH and the set data models can be used to represent and exchange archival metadata in a distributed environment

Formal Models for Digital Archives: NESTOR and the 5S

Archives are a valuable part of our cultural heritage but despite their importance, the models and technologies that have been developed over the past two decades in the Digital Library (DL) field have not been specifically tailored to them. This is especially true when it comes to formal and foundational frameworks, as the Streams, Structures, Spaces, Scenarios, Societies (5S) model is. Therefore, we propose an innovative formal model, called NEsted SeTs for Object hieRarchies (NESTOR), for archives, explicitly built around the concepts of context and hierarchy which play a central role in the archival realm. We then use NESTOR to extend the 5S model offering the possibility of opening up the full wealth of DL methods to archives. We provide account for this by presenting two concrete applications