Enrico Franconi

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We consider diierent methods of optimizing the classiication process of terminological representation systems, and evaluate their eeect on three diierent types of test data. Though these techniques can probably be found in many existing systems, until now there has been no coherent description of these techniques and their impact on the performance of a(More)
Knowledge bases data bases and object oriented systems referred to in the pa per as Object Centered systems all rely on attributes as the main construct used to associate properties to objects among these a fundamental role is played by the so called part whole relation The representation of such a structural informa tion usually requires a particular(More)
Census data provide valuable insights on the economic, social and demographic conditions and trends occurring in a country. Census data is collected by means of millions of questionnaires, each one including the details of the persons living together in the same house. Before the data from the questionnaires is sent to the statisticians to be analysed, a(More)
This paper surveys the temporal extensions of description logics appearearing in the literature. The analysis considers a large spectrum of approaches appearearing in the temporal description logics area: from the loosely coupled approaches – which comprise, for example, the enhancement of simple description logics with a constraint based mechanism – to the(More)
A class of interval-based temporal languages for uniformly representing and reasoning about actions and plans is presented. Actions are represented by describing what is true while the action itself is occurring, and plans are constructed by temporally relating actions and world states. The temporal languages are members of the family of Description Logics,(More)
We consider query answering on Description Logic (DL) ontologies with DBoxes, where a DBox is a set of assertions on individuals involving atomic concepts and roles called DBox predicates. The extension of a DBox predicate is exactly defined in every interpretation by the contents of the DBox, i.e., a DBox faithfully represents a database whose table names(More)
The SEWASIE (SEmantic Webs and AgentS in Integrated Economies) project aims at enabling a uniform access to heterogeneous data sources through an integrated ontology. The overall project development strictly follows a user-centred design methodology. Users have been involved from the very beginning and are constantly participating in the design and testing(More)
In this paper we give a robust logical and computational characterisation of peer-to-peer (p2p) database systems. We first define a precise model-theoretic semantics of a p2p system, which allows for local inconsistency handling. We then characterise the general computational properties for the problem of answering queries to such a p2p system. Finally, we(More)
Consistent query answering is the problem of characterizing and computing the semantically correct answers to queries from a database that may not satisfy certain integrity constraints. Consistent answers are characterized as those answers that are invariant under all minimally repaired versions of the original database. We study the problem of repairing(More)