Z39.50 is a client/server protocol widely used in digital libraries and museums for searching and retrieving information spread over a number of heterogeneous sources. To overcome semantic and schematic discrepancies among the various data sources the protocol relies on a world view of information as a flat list of fields, called Access Points (AP). One of the major issues for building Z39.50 wrappers is to map this unstructured list of APs to the underlying source data. Unfortunately, existing Z39.50 wrappers have been developed from scratch and they do not provide high-level mapping languages with veriffiable properties. In this paper, we propose a Description Logic based toolkit for the declarative specification of Z39.50 wrappers. We claim that the conceptualization of AP mappings enables a formal validation of the query translation quality and therefore ensures the quality of the retrieved data. Finally, it allows to tackle a number of Z39.50 pending issues (e.g., metadata retrieval, query failures due to unsupported APs, etc.) by enriching the generated Z39.50 wrappers with a number of added-value services such as conceptual structuring of flat Z39.50 vocabularies and intelligent Z39.50 query assists.
['Yannis Velegrakis', 'Vassilis Christophides', 'Panos Constantopoulos']
Declarative Specification of Z39.50 Wrappers Using Description Logics