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XML is becoming the universal format for data exchange between applications. Recently, the emergence of Web services as standard means of publishing and accessing data on the Web introduced a new class of XML documents, which we call <i>intensional</i> documents. These are XML documents where some of the data is given explicitly while other parts are(More)
We present a model for data organized as graphs. Regular expressions over the types of the node and edge labels are used to qualify connected subgraphs. An algebraic language based on these regular expressions and supporting a restricted form of recursion is introduced. A natural application of this model and its query language is hypertext querying.
Electronic commerce is emerging as a major Web-supported application. In this paper we argue that database technology can, and should, provide the backbone for a wide range of such applications. More precisely, we present here the ActiveViews system, which, relaying on an extensive use of database features including views, active rules (triggers), and(More)
This paper deals with some modeling aspects that have to be addressed in the context of the integration of heterogeneous and autonomous XML resources. We propose an integration system, but the emphasis of this paper is neither on its algorithmic aspects nor on its technical details. Instead, we focus on the significance of offering appropriate high-level(More)
In this paper we propose a mediator architecture for the querying and integration of Web-accessible XML data sources. Our contributions are (i) the definition of a simple but expressive mapping language, following the local as view approach and describing XML resources as local views of some global schema, and (ii) efficient algorithms for rewriting user(More)
In this paper we present a new approach for building metadata schemas by integrating existing ontologies and structured vocabularies (thesauri). This integration is based on the specification of inclusion relationships between thesaurus terms and ontology concepts and results in application-specific metadata schemas incorporating the structural views of(More)
Acknowledgements Everything started one day of June 2000, when I decided to go Erasmus at the Ecole Polytechnique in Paris, and I was suggested to attend there the databases lectures given by Prof. Abiteboul. When in January 2001, I decided to follow the extra-lectures of Prof. Abiteboul in order to present a databases project, he was so nice to sit beside(More)
The need for descriptive information, i.e., metadata, about Web resources has been recognized in several application contexts (e.g., digital libraries, portals). The Resource Description Framework (RDF) aims at facilitating the creation and exchange of metadata, as directed labeled graphs serialized in XML. In particular, the de nition of schema(More)
We present a new provenance model for generating <i>fine-grained</i> data and service dependencies within XML data processing workflows. Our approach follows the widely used <i>black box transformation</i> semantics [15] in which service components produce new outputs from their inputs (without transformation). The heart of the model are <i>data dependency(More)