In this paper we propose a matching algorithm for measuring the structural similarity between an XML document and a DTD. The matching algorithm, by comparing the document structure against the one the DTD requires, is able to identify commonalities and differences. Differences can be due to the presence of extra elements with respect to those the DTD requires and to the absence of required elements. The evaluation of commonalities and differences gives raise to a numerical rank of the structural similarity. Moreover, in the paper, some applications of the matching algorithm are discussed. Specifically, the matching algorithm is exploited for the classification of XML documents against a set of DTDs, the evolution of the DTD structure, the evaluation of structural queries, the selective dissemination of XML documents, and the protection of XML document contents.

In this paper we investigate the problem of XML Schema evolution. We first discuss the different kinds of changes that may be needed on an XML Schema. Then, we investigate how to minimize document revalidation, that is, detecting the document parts potentially invalidated by the schema changes that should be revalidated.

No abstract

D i p a r t i m e n t o di I n f o r m a t i c aAbstract. Although many temporal extensions to the relationM data model have been proposed, there is no comparable amount of work in the context of object-oriented data models. This paper presents T_Chimera, a temporal extension of the Chimera data model. The main contribution of this work is to define a formal temporal object-oriented data model and to address on a formal basis several issues deriving from the introduction of time in an object-oriented context.

Abstract. In order to enable interoperability between ontology-based systems, ontology matching techniques have been proposed. However, when the generated mappings suffer from logical flaws, their usefulness may be diminished. In this paper we present an approximate method to detect and correct violations to the so-called conservativity principle where novel subsumption entailments between named concepts in one of the input ontologies are considered as unwanted. We show that this is indeed the case in our application domain based on the EU Optique project. Additionally, our extensive evaluation conducted with both the Optique use case and the data sets from the Ontology Alignment Evaluation Initiative (OAEI) suggests that our method is both useful and feasible in practice.