G. Terracina | Università della Calabria (original) (raw)

Datalog ∃ is the extension of Datalog, allowing existentially quantified variables in rule heads.... more Datalog ∃ is the extension of Datalog, allowing existentially quantified variables in rule heads. This language is highly expressive and enables easy and powerful knowledge-modeling, but the presence of existentially quantified variables makes reasoning over Datalog ∃ undecidable, in the general case. The results in this paper enable powerful, yet decidable and efficient reasoning (query answering) on top of Datalog ∃ programs. On the theoretical side, we define the class of parsimonious Datalog ∃ programs, and show that it allows of decidable and efficiently-computable reasoning. Unfortunately, we can demonstrate that recognizing parsimony is undecidable. However, we single out Shy, an easily recognizable fragment of parsimonious programs, that significantly extends both Datalog and Linear-Datalog ∃ , while preserving the same (data and combined) complexity of query answering over Datalog, although the addition of existential quantifiers. On the practical side, we implement a bottom-up evaluation strategy for Shy programs inside the DLV system, enhancing the computation by a number of optimization techniques to result in DLV ∃ -a powerful system for answering conjunctive queries over Shy programs, which is profitably applicable to ontology-based query answering. Moreover, we carry out an experimental analysis, comparing DLV ∃ against a number of stateof-the-art systems for ontology-based query answering. The results confirm the effectiveness of DLV ∃ , which outperforms all other systems in the benchmark domain.

A data integration system provides transparent access to different data sources by suitably combi... more A data integration system provides transparent access to different data sources by suitably combining their data, and providing the user with a unified view of them, called global schema. However, source data are generally not under the control of the data integration process, thus integrated data may violate global integrity constraints even in presence of locally-consistent data sources. In this scenario, it may be anyway interesting to retrieve as much consistent information as possible. The process of answering user queries under global constraint violation is called consistent query answering (CQA). Several notions of CQA have been proposed, e.g. depending on whether the information in the database is assumed to be sound or complete. This paper provides a contribution in this setting; it uniforms solutions coming from different perspectives under a common core and provides some optimizations designed to identify and isolate the inefficient part of the computation of consistent answers. The effectiveness of the approach is evidenced by experimental results reported in the paper.

19th IEEE Symposium on Computer-Based Medical Systems (CBMS'06), 2006

Identifying protein secondary structures is a difficult task. Recently, a lot of software tools f... more Identifying protein secondary structures is a difficult task. Recently, a lot of software tools for protein secondary structures prediction have been produced and made avail- able on-line, mostly with good performances. However, pre- diction tools work correctly for families of proteins, such that users have to know which predictor to use for a given unknown protein. We propose a framework

Lecture Notes in Computer Science, 2003

In this paper we propose an XML-based adaptive multiagent system for handling e-commerce activiti... more In this paper we propose an XML-based adaptive multiagent system for handling e-commerce activities. More specifically, our system aims at supporting a customer, visiting an e-commerce site, in the search of products and/or services present therein and appearing to be appealing according to her/his past interests and behaviour. The system is adaptive w.r.t. the profile of both the customer and the device she/he is exploiting for visiting the site. Finally, the system is XML-based since XML is exploited for both storing the agent ontologies and handling the agent communication.

Proceedings of the 2006 ACM symposium on Applied computing - SAC '06, 2006

Lecture Notes in Computer Science, 2005

The post-genomic era showed up a wide range of new challenging issues for the areas of knowledge ... more The post-genomic era showed up a wide range of new challenging issues for the areas of knowledge discovery and intelligent information management. Among them, the discovery of complex pattern repetitions in string databases plays an important role, specifically in those contexts where even what are to be considered the interesting pattern classes is unknown. This paper provides a contribution in this precise setting, proposing a novel approach, based on disjunctive logic programming extended with several advanced features, for discovering interesting pattern classes from a given data set.

Lecture Notes in Computer Science, 2000

... E''ij; for each k, such that 1 < k < n, an attribute Ak is added to E'&#... more ... E''ij; for each k, such that 1 < k < n, an attribute Ak is added to E''ij for representing overlapping attributes Aik and Ajk ... work, we are adding the prototype module implementing the techniques presented here in a more general and complex system called DIKE Database Intensional ...

IEEE Transactions on Knowledge and Data Engineering, 2008

The discovery of information encoded in biological sequences is assuming a prominent role in iden... more The discovery of information encoded in biological sequences is assuming a prominent role in identifying genetic diseases and in deciphering biological mechanisms. This information is usually encoded in patterns frequently occurring in the sequences, also called motifs. In fact, motif discovery has received much attention in the literature, and several algorithms have already been proposed, which are specifically tailored to

ACS/IEEE International Conference on Computer Systems and Applications, 2003. Book of Abstracts.

caratteristiche: (i) ` e specializzato per la manipolazione di documenti XML; (ii) ` e semi-autom... more caratteristiche: (i) ` e specializzato per la manipolazione di documenti XML; (ii) ` e semi-automatico; (iii) ` e semantico e " leggero " ; (iv) consente la scelta del livello di flessibilità con cui realizzare l'integrazione.

Node Influence Maximization and Influential Node Charac-terization are classical problems in Soci... more Node Influence Maximization and Influential Node Charac-terization are classical problems in Social Network Analysis. Indeed, in the past, they have been deeply investigated with reference to single social networks. However, the current scenario is multi-social-network. Here, many social networks coexist and are strictly connected to each other, thanks to those users who join more social networks, acting as bridges among them. But, what happens to Node Influence Maximiza-tion and Influential Node Characterization problems when passing from a Single-Social-Network to a Multi-Social-Network Scenario? In this pa-per we answer this question. Thanks to the definition of a model for a Multi-Social-Network Scenario and a large set of experiments, we show that, in this context, new actors and new features must be taken into ac-count. In this activity, Disjunctive Logic Programming provided us with a powerful and flexible tool for an easy set-up and implementation of our investigation.

Lecture Notes in Computer Science, 2013

In this paper we present a technique based on logic programming for data cleaning, and its applic... more In this paper we present a technique based on logic programming for data cleaning, and its application to a real use case from the Italian Healthcare System. The use case is part of a more complex project developing a business intelligence suite for the analysis of distributed archives of tumor-based diseases.

Lecture Notes in Computer Science, 2008

... Step 1. Translate P in an equivalent program P ; Step 2. Translate each rule of P in a corres... more ... Step 1. Translate P in an equivalent program P ; Step 2. Translate each rule of P in a corresponding SQL statement; Step 3. Compose and execute the query plan of statements generated in Step 2 on the DBMS; Step 4. Generate the residual program and load it in the Model ...

Lecture Notes in Computer Science, 2003

Lecture Notes in Computer Science, 2002

Page 1. A Model and a Toolkit for Supporting Incremental Data Warehouse Construction Paolo Naggar... more Page 1. A Model and a Toolkit for Supporting Incremental Data Warehouse Construction Paolo Naggar1, Luigi Pontieri2, Mariella Pupo3, Giorgio Terracina4, and Emanuela Virardi1 ... In Proc. of ER Workshops, Singapore, 1998: 105–116. 12. JC Trujillo, M. Palomar, J. Gómez. ...

Lecture Notes in Computer Science

Comparing pairs of sequences is a problem emerging in several application areas (ranging from mol... more Comparing pairs of sequences is a problem emerging in several application areas (ranging from molecular biology, to signal processing, text retrieval, and intrusion detection, just to cite a few) and important results have been achieved through the years. In fact, most of the algorithms in the literature rely on the assumption that matching symbols (or at least a substitution schema among them) are known in advance. This paper opens the way to a more involved mechanism for sequence comparison, where determining the best substitution schema is also part of the matching problem. The basic idea is that any symbol of one sequence can be correlated with many symbols of the other sequence, provided each correlation frequently occurs over the various positions. The approach fits a variety of problems difficult to be handled with classical techniques, particularly where strings to be matched are defined over different alphabets.

Lecture Notes in Computer Science, 2011

Abstract. The attention received by query optimization is constantly growing, but efficiently rea... more Abstract. The attention received by query optimization is constantly growing, but efficiently reasoning over natively distributed data is still an open issue. Three main problems must be faced in this context: (i) rules to be processed may contain many atoms and may involve complex joins ...

Proceedings - 2005 IEEE/WIC/ACM International Conference on Intelligent Agent Technology, IAT'05, 2005

... De Meo Giovanni Quattrone DIMET DIMET Universit`a “Mediterranea” di Reggio Calabria Universit... more ... De Meo Giovanni Quattrone DIMET DIMET Universit`a “Mediterranea” di Reggio Calabria Universit`a “Mediterranea” di Reggio Calabria Via Graziella, Localit`a Feo di Vito Via Graziella, Localit`a Feo di Vito 89060 Reggio Calabria, Italy 89060 Reggio Calabria, Italy demeo@ ...