Preface

Thomas Eiter, Domenico Lembo
2005 Journal of Applied Logic  
Preface Information integration is one of the key issues for building powerful global information systems that are targeted to provide broad information access in the emerging information society. A number of approaches to information integration have been proposed, rooted in different areas and underlying principles. It appears, however, that especially the use of logic-based methods in information integration is promising and attractive to address the many aspects and problems which arise in
more » ... he context of information integration. For example, such methods are helpful in giving formal semantics to data integration, in comparing the expressiveness of approaches, as well as in computation and establishing properties of data integration systems. This special issue contains a selection of papers that have been presented, in a preliminary version, at the workshop on "Logic-based methods for information integration", organized within the CoLogNET Network of Excellence in Computational Logic, and held at the Technical University of Vienna, on August the 23rd, 2003. The talks of the workshop have addressed several crucial aspects in information integration, such as integration of semistructured data, logic-based query reformulation, consistent query answering, and ontology-based integration. The presentations stimulated interesting discussions during the workshop, and showed the importance and research potential of logic-based methods in this field. In order to highlight and communicate this to a broader forum, full papers of the talks have been issued for a special issue of this journal, of which four have been selected for inclusion. The first paper, "Rule-based schema matching for ontology-based mediators", by Gunter Saake, Kai-Uwe Sattler, and Stefan Conrad, deals with schema matching. This is an important subtask of data integration, which addresses the problem of defining a mapping between the elements of two schemas taken as input based on semantic correspondences. In this respect, Saake et al. present a semi-automatic schema matching approach which is based on the use of declarative logic rules involving elements of the schemas of the data sources to be integrated by an ontology-based mediator. The logic rules allow for an automatic definition of the mapping establishing the relationship between different source schemas and the ontology global level of the application. The second paper, "Logic-based XML data integration: a semi-materializing approach", by Wolfgang May, considers data integration for XML. In this paper, May extends his previous studies on a pure warehouse approach for integrating data to a semi-materialized approach. The approach is based on an extended XML model and on a language which is 1570-8683/$ -see front matter 
doi:10.1016/j.jal.2004.07.019 fatcat:szwziitwobhzxbyyz263mh436e