Mariano Rodriguez-Muro

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Ontologies provide a conceptualization of a domain of interest. Nowadays, they are typically represented in terms of Description Logics (DLs), and are seen as the key technology used to describe the semantics of information at various sites. The idea of using ontologies as a conceptual view over data repositories is becoming more and more popular, but for(More)
We present the architecture and technologies underpinning the OBDA system Ontop and taking full advantage of storing data in relational databases. We discuss the theoretical foundations of Ontop: the tree-witness query rewriting, T -mappings and optimisations based on database integrity constraints and SQL features. We analyse the performance of Ontop in a(More)
Current techniques for query answering over DL-Lite ontologies have severe limitations in practice, since they either produce complex queries that are inefficient during execution, or require expensive data pre-processing. In light of this, we present two complementary sets of results that aim at improving the overall peformance of query answering systems.(More)
In this paper we present Mastro, a Java tool for ontology-based data access (OBDA) developed at the Sapienza Università di Roma and at the Free University of Bozen-Bolzano. Mastro manages OBDA systems in which the ontology is specified in DL-LiteA,id , a logic of the DL-Lite family of tractable Description Logics specifically tailored to ontology-based data(More)
Motivation. One of the most important uses of semantic technology is that of Ontology Based Data Access (OBDA), where the objective is to use shared vocabularies and ontologies as means to access data living in possibly disperse and heterogenous data sources (e.g., relational DBMS, XML databases, spreadsheets, etc.) Today this task often involves an ETL(More)
In this paper we present Ontop, an open-source Ontology Based Data Access (OBDA) system that allows for querying relational data sources through a conceptual representation of the domain of interest, provided in terms of an ontology, to which the data sources are mapped. Key features of Ontop are its solid theoretical foundations, a virtual approach to OBDA(More)
Nowadays, it is widely accepted that the data warehouse design task should be largely automated. Furthermore, the data warehouse conceptual schema must be structured according to the multidimensional model and as a consequence, the most common way to automatically look for subjects and dimensions of analysis is by discovering functional dependencies (as(More)
Ontology Based Data Access (OBDA) [4] is a paradigm of accessing data trough a conceptual layer. Usually, the conceptual layer is expressed in the form of an RDF(S) [10] or OWL [15] ontology, and the data is stored in relational databases. The terms in the conceptual layer are mapped to the data layer using mappings which associate to each element of the(More)
Ontology Based Data Access (OBDA) has drawn considerable attention from the OWL and RDF communities. In OBDA, instance data is accessed by means of mappings, which state the relationship between the data in a data source (e.g., an RDBMSs) and the vocabulary of an ontology. In this paper we present Quest, a new system for OBDA focused on fast and efficient(More)