Papers by Antonella Poggi
Proceedings of the Twenty-Seventh International Joint Conference on Artificial Intelligence
We present the framework of ontology-based data access, a semantic paradigm for providing a conve... more We present the framework of ontology-based data access, a semantic paradigm for providing a convenient and user-friendly access to data repositories, which has been actively developed and studied in the past decade. Focusing on relational data sources, we discuss the main ingredients of ontology-based data access, key theoretical results, techniques, applications and future challenges.
Semantic Web
In this paper we present MASTRO, a Java tool for ontology-based data access (OBDA) developed at S... more In this paper we present MASTRO, a Java tool for ontology-based data access (OBDA) developed at Sapienza Università di Roma and at the Free University of Bozen-Bolzano. MASTRO manages OBDA systems in which the ontology is specified in DL-Lite A,id , a logic of the DL-Lite family of tractable Description Logics specifically tailored to ontology-based data access, and is connected to external JDBC enabled data management systems through semantic mappings that associate SQL queries over the external data to the elements of the ontology. Advanced forms of integrity constraints, which turned out to be very useful in practical applications, are also enabled over the ontologies. Optimized algorithms for answering expressive queries are provided, as well as features for intensional reasoning and consistency checking. MASTRO provides a proprietary API, an OWLAPI compatible interface, and a plugin for the Protégé 4 ontology editor. It has been successfully used in several projects carried out in collaboration with important organizations, on which we briefly comment in this paper.
Ontology-based data access (OBDA) is a novel paradigm for accessing large data repositories throu... more Ontology-based data access (OBDA) is a novel paradigm for accessing large data repositories through an ontology, that is a formal description of a domain of interest. Supporting the management of OBDA applications poses new challenges, as it requires to provide effective tools for (i) allowing both expert and non-expert users to analyze the OBDA specification, (ii) collaboratively documenting the ontology, (iii) exploiting OBDA services, such as query answering and automated reasoning over ontologies, e.g., to support data quality check, and (iv) tuning the OBDA application towards optimized performances. To fulfill these challenges, we have built a novel system, called MASTRO STUDIO, based on a tool for automated reasoning over ontologies, enhanced with a suite of tools and optimization facilities for managing OBDA applications. To show the effectiveness of MASTRO STUDIO, we demonstrate its usage in one OBDA application developed in collaboration with the Italian Ministry of Economy and Finance.
WORKPAD (EU STREP project FP6-2005-IST-5-034749) is an experimental platform for Crisis Response ... more WORKPAD (EU STREP project FP6-2005-IST-5-034749) is an experimental platform for Crisis Response which adopts a decentralized, event-driven approach to overcome problems and limitations of centralized systems. The flexibility of P2P networking is relevant when different organizations must get rapidly integrated the one another, without resorting on standardized ontologies and centralized middleware components. This paper illustrates the main features of the Information Integration platform we've designed. A number of relevant technical and theoretical issues related to decentralized platforms are discussed in the light of specific needs of Crisis Response.
Proceedings of the 22nd National Conference on Artificial Intelligence Volume 1, 2007
A Description Logics knowledge base is constituted by two components, called TBox and ABox, where... more A Description Logics knowledge base is constituted by two components, called TBox and ABox, where the former expresses general knowledge about the concepts and their relationships, and the latter describes the properties of instances of concepts. We address the problem of how to deal with changes to a Description Logic knowledge base, when these changes affect only its ABox. We consider two types of changes, namely update and erasure, and we characterize the semantics of these operations on the basis of the approaches proposed by Winslett and by Katsuno and Mendelzon. It is well known that, in general, Description Logics are not closed with respect to updates, in the sense that the set of models corresponding to an update applied to a knowledge base in a Description Logic L may not be expressible by ABoxes in L. We show that this is true also for erasure. To deal with this problem, we introduce the notion of best approximation of an update (erasure) in a DL L, with the goal of characterizing the L ABoxes that capture the update (erasure) at best. We then focus on DL-LiteF , a tractable Description Logic, and present polynomial algorithms for computing the best approximation of updates and erasures in this logic, which shows that the nice computational properties of DL-LiteF are retained in dealing with the evolution of the ABox. Recent years have witnessed a strong interest in Description Logics (Baader et al. 2003) (DL). From one hand, DLs are widely considered as the logical basis for representing and reasoning over web ontologies 1. On the other hand, the use of DL systems such as RacerPro, FaCT++, Pellet, QuOnto 2 is becoming more and more common in various application areas. These systems essentially provide basic reasoning services over DL knowledge bases, such as consistency checking, subsumption, instance checking, and, at least some of them, query answering. However, the kind of support they provide is somehow limited to reasoning over a static knowledge base. This has to be contrasted with the increasing interest in supporting the evolution of a DL knowledge base. Indeed, recent papers, in particular, (Haase &
In Ontology Based Data Access (OBDA), the aim is to use an ontol- ogy to mediate access to data. ... more In Ontology Based Data Access (OBDA), the aim is to use an ontol- ogy to mediate access to data. The main contribution of this work is to demon- strate two key components of an OBDA system, whose combination allows on- tology practitioners to finally realize end-to-end OBDA systems. The first com- ponent is an OBDA-enabled reasoner, named DIG-MASTRO. The second com- ponent is the OBDA Plugin for Prot´ ege, that in conjunction with the ontology editing features of Proteg´ e, functions as an OBDA system designer.
Résumé: Dans cet article, nous nous intéresson a la construction d'entrepôts dynamique a part... more Résumé: Dans cet article, nous nous intéresson a la construction d'entrepôts dynamique a partir de ressources du Web, en utilisant notamment des services disponibles sur le web. Notre contribution tient essentiellemen a la définition d'une nouvelle architecture basée autour de services web (e.g. SOAP) et du language ActiveXML, nous permettant de résoudre notamment lesprobì emes suivant: (i) l'acquisition de pages du Web, (ii) le contrôle des changements de ces pages et (iii) l'enrichissement des données et méta-données par l'utilisation de services Web. Lesys eme est développé en Ac-tiveXML, un langage et unsys eme permettant l'intégration d'appel a des services Web au sein d'un document XML.
Today's fast and continuous growth of large business organizations enforces the need to integrate... more Today's fast and continuous growth of large business organizations enforces the need to integrate and share data coming from a number of heterogeneous and distributed data sources. To solve this kind of problem, data federation tools suggest the adoption of a database management system as a kind of middleware infrastructure that uses a set of wrappers to access heterogeneous data sources. In this paper, we highlight federation tools limitations with respect to the information integration problem and show how data integration systems overcome such limitations. We propose then two different techniques to implement a data integration system using a data federation tool. Finally, we present experimental results that compare the two solutions.
DL-Lite is a family of Description Logics (DLs) whose aim is to capture some of the most popular ... more DL-Lite is a family of Description Logics (DLs) whose aim is to capture some of the most popular conceptual modeling formalisms, such as Entity-Relationship model [4] and UML class diagrams 1, while preserving the tractability of the most important reasoning tasks, such as ontology satisfiability and query answering of arbitrary (union
Most existing human-computer interfaces are now based on the WIMP (Windows, Icons, Menus, Pointer... more Most existing human-computer interfaces are now based on the WIMP (Windows, Icons, Menus, Pointers) paradigm and on the desktop metaphor. Each application is targeted towards editing one specific type of “document”. Current
We report on an experimentation of Ontology-based Data Access (OBDA) carried out in a joint proje... more We report on an experimentation of Ontology-based Data Access (OBDA) carried out in a joint project with SAPIENZA University of Rome, Free University of Bolzano, and Monte dei Paschi di Siena (MPS), where we used MASTRO for accessing, by means of an ontology, a set of data sources of the actual MPS data repository. By both looking at these sources, and by interviews with domain experts, we designed both the ontology representing the conceptual model of the domain, and the mappings between the ontology and the sources. The project confirmed the importance of several distinguished features of DL-LiteA,Id to express the ontology and has shown very good performance of the MASTRO system in all the reasoning tasks, including query answering, which is the most important service required in the application.
In this paper we present Mastro, a Java tool for ontologybased data access (OBDA) developed at Sa... more In this paper we present Mastro, a Java tool for ontologybased data access (OBDA) developed at Sapienza Università di Roma. Mastro manages OBDA systems in which the ontology is specified in a logic of the DL-Lite family of Description Logics specifically tailored to ontology-based data access, and is connected to external data management systems through semantic mappings that associate SQL queries over the external data to the elements of the ontology. Advanced forms of integrity constraints, which turned out to be very useful in practical applications, are also enabled over the ontologies. Optimized algorithms for answering expressive queries are provided, as well as features for intensional reasoning and consistency checking. Mastro has been successfully used in several projects carried out in collaboration with important organizations, on which we briefly comment in this paper.
Lecture Notes in Computer Science, 2007
Objectives Despite the large number of software tools named "digital library systems", there is n... more Objectives Despite the large number of software tools named "digital library systems", there is no agreement yet on what Digital Library [Management] Systems (DLMSs) are and on which functionality they must provide. Existing systems are heterogeneous in scope and focus on very different aspects and functionality. These systems range from digital objects/metadata repositories, reference linking systems, archives and commercial systems that provide administration functions, to complex systems (mainly developed in research environments) that integrate advanced digital library services. Research on DLMSs concerns several different areas. It is often difficult to compare or combine the results achieved in these areas since it is not always clear how they are related, and how they can impact on or constrain one another. This fragmentation of results hinders the embedding of new research achievements into real world systems. These problems have a common origin: the lack of any agreement on the foundations for Digital Library Management Systems. The objective of this DELOS activity is to define a DLMS reference model, i.e. a formal and conceptual framework describing the characteristics of this particular type of information system. The model will exploit the understanding of the architecture and functionality expected from an operational DLMS which has been acquired by DELOS research groups over the years. This model will identify and characterize key concepts of a DLMS, such as the information space, documents handled, user profile, services, architecture, etc. The reference model activity, begun by a core group of DELOS members, will soon be taken up by other DELOS groups, working from the perspectives of different domains. Liaisons with similar activities carried out by other research groups and initiatives at international level will be established in order to achieve a global and stable level of consensus on the model.
Proceedings of the international workshop in conjunciton with AVI 2006 on Context in advanced interfaces - AVI '06, 2006
In this paper we describe briefly three systems: onCue a desktop internet-access toolbar, Snip!t ... more In this paper we describe briefly three systems: onCue a desktop internet-access toolbar, Snip!t a web-based bookmarking application and ontoPIM an ontology-based personal task-management system. These embody context issues to differing degrees, and we use them to exemplify more general issues concerning the use of contextual information in 'intelligent' interfaces. We look at issues relating to interaction and 'appropriate intelligence', at different types of context that arise and at architectural lessons we have learnt. We also highlight outstanding problems, in particular the need to computationally describe and communicate context where reasoning and inference is distributed.
Uploads
Papers by Antonella Poggi