Antonella Poggi

• PhD
• Ricercatore at Sapienza University of Rome

The Datalog query language can express several powerful recursive properties, often crucial in real-world scenarios. While answering such queries is feasible over relational databases, the picture changes dramatically when data is enriched with intensional knowledge. It is indeed well-known that answering Datalog queries is undecidable already over...

In Ontology-Based Data Management (OBDM), an abstraction of a source query q is a query over the ontology capturing the semantics of q in terms of the concepts and the relations available in the ontology. Since a perfect characterization of a source query may not exist, the notions of best sound and complete approximations of an abstraction have be...

OWL 2 QL is a standard profile of the OWL 2 ontology language, specifically tailored to Ontology-Based Data Management. Inspired by recent work on higher-order Description Logics, in this paper we present a new semantics for OWL 2 QL ontologies, called Metamodeling Semantics (MS), and show that, in contrast to the official Direct Semantics (DS) for...

In Ontology-Based Data Access (OBDA), a domain ontology is linked to the data sources of an organization in order to query, integrate and manage data through the concepts and relations of the domain of interest, thus abstracting from the technical details of the data layer implementation. While the great majority of contributions in OBDA in the las...

In the context of the Description Logic DL-Liteℛ≠, i.e., DL-Liteℛ without UNA and with inequality axioms, we address the problem of adding to unions of conjunctive queries (UCQs) one of the simplest forms of negation, namely, inequality. It is well known that answering conjunctive queries with unrestricted inequalities over DL-Liteℛ ontologies is i...

We study the problem of associating formal semantic descriptions to data services. We base our proposal on the Ontology-based Data Access paradigm, where a domain ontology is used to provide a semantic layer mapped to the data sources of an organization. The basic idea is to explain the semantics of a data service in terms of a query over the ontol...

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, technique...

We present the framework of ontology-based data access, a semantic paradigm for providing a con- venient and user-friendly access to data reposito- ries, which has been actively developed and stud- ied in the past decade. Focusing on relational data sources, we discuss the main ingredients of ontology-based data access, key theoretical results, tec...

While big data analytics is considered as one of the most important paths to competitive advantage of today’s enterprises, data scientists spend a comparatively large amount of time in the data preparation and data integration phase of a big data project. This shows that data integration is still a major challenge in IT applications. Over the past...

Metamodeling and metaquerying are gaining momentum in the context of both conceptual modeling and semantic web. Indeed it has been largely recognized that metamodeling represents a very useful tool to formalize complex patterns involving elements of the domain of interest, that otherwise are forced to be excluded from the modeling process, and a nu...

After years of focus on technologies for big data storing and processing, many observers are pointing out that making sense of big data cannot be done without suitable tools for conceptualizing, preparing, and integrating data (see http://www.dbta.com/). Research in the last years has shown that taking into account the semantics of data is crucial...

OWL 2 QL is the profile of OWL 2 targeted to Ontology-Based Data Access (OBDA) scenarios, where large amount of data are to be accessed, and thus answering conjunctive queries over data is the main task. However, this task is quite restrained wrt the classical KR Ask-and-Tell framework based on querying the whole theory, not only facts (data). If w...

In this paper, we introduce a methodology to be employed for collaborative projects. This methodology, called HORIZON, has been successfully employed in the past for FP6 and FP7 EU projects, but we strongly believe it can be fruitfully employed for H2020 projects as well, guaranteeing quality requirements to be met.

Hi(DL − Lite R ) is a higher-order Description Logic obtained from DL − Lite R by adding metamodeling features, and is equipped with a query language that is able to express higher-order queries. We investigate the problem of answering a particular class of such queries, called instance higher-order queries, posed over Hi(DL − Lite R ) knowledge ba...

In this paper we present an ontology-based data management (OBDM) project concerning the Italian public debt domain, carried out within a joint collaboration between Sapienza University of Rome and the Department of Treasury of the Italian Ministry of Economy and Finance. We discuss the motivations at the basis of this project and present the main...

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 sp...

Ontology-based data access (OBDA) is a novel paradigm for ac-cessing 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 s...

In ontology-based data access (OBDA), an ontology is connected to autonomous, and generally pre-existing, data repositories through mappings, so as to provide a high-level, conceptual view over such data. User queries are posed over the ontology, and answers are computed by reasoning both on the ontology and the mappings. Query answering in OBDA sy...

Ontology-based data access (OBDA) is a new paradigm for manag-ing complex information systems through semantic technologies. In this paper we present what we believe is the first industrial experience of a comprehensive OBDA project, developed jointly by Sapienza University of Rome and the De-partment of Treasury of the Italian Ministry of Econonom...

In this paper we present the current version of Mastro, a system for ontologybased data access (OBDA) developed at Sapienza Università di Roma. Mastro allows users for accessing external data sources by querying an ontology expressed in a fragment of the W3C Web Ontology Language (OWL). As in data integration [5], mappings are used in OBDA to speci...

In current electronic environments, the ever-increasing amount of personal information, means that users focus more on managing their information rather than using it to accomplish their objectives. To overcome this problem, a user task-based interactive environment is needed to help users focus on tasks they wish to perform rather than spending mo...

In this paper we present Mastro, a Java tool for ontology-based 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 t...

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...

Ontologies offer a flexible and expressive layer of abstraction, very useful for capturing the semantics of information repositories and facilitating their retrieval either by the user or by the system to support user tasks. This work presents an ontology-based user profiler, in the context of a Personal Interaction Management System (PIMS). The pr...

We study models of incomplete information for XML, their computational properties, and query answering. While our approach is motivated by the study of relational incompleteness, incomplete information in XML documents may appear not only as null values but also as missing structural information. Our goal is to provide a classification of incomplet...

This paper takes as its premise that the web is a place of action, not just information, and that the purpose of global data is to serve human needs. The paper presents several component technologies, which together work towards a vision where many small micro-applications can be threaded together using automated assistance to enable a unified and...

The relational model has recently been extended to so-called K-relations in which tuples are assigned a unique value in a semiring K. A query language, denoted by RAK+, similar to the classical positive relational algebra, allows for the querying of K-relations. In this paper, we define more expressive query languages for K-relations that extend RA...

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,...

This work presents the visual user interface of the On-TIME system, a task-centered information management system, whose aim is to actively participate to and support the user tasks. One of the key challenges that needs to be addressed for the success of On-TIME, is the design of a user friendly interface. Being On-TIME based on the use of a so-cal...

Several areas of research and various application domains have been concerned in the last years with the problem of dealing with incomplete databases. Data integration as well as the Semantic Web are notable examples. Surprisingly, while many research efforts have been focusing on several interesting issues related to incomplete databases, as query...

A Description Logic (DL) ontology is constituted by two components, a TBox that expresses general knowledge about the concepts and their relationships, and an ABox that describes the properties of individuals that are instances of concepts. We address the problem of how to deal with changes to a DL ontology, when these changes affect only the ABox,...

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...

This demonstration concerns the visual user interface of the On-TIME system, a task-centered information management system, whose aim is to actively participate to and support the user tasks. The design of a user friendly interface is one of the key challenges that needs to be addressed for the success of On-TIME. Being On-TIME based on the use of...

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,...

We study models of incomplete information for XML, their computational properties, and query answering. While our approach is motivated by the study of relational incomplete- ness, incomplete information in XML documents may appear not only as null values but also as missing structural infor- mation. Our goal is to provide a classification of incom...

The goal of data integration is to provide a uniform access to a set of heterogeneous data sources, freeing the user from the knowledge about where the data are, how they are stored, and how they can be accessed. One of the outcomes of the research work carried out on data integration in the last years is a clear conceptual architecture, comprising...

The paper investigates fundamental decision problems and composition synthesis for Web services commonly found in practice. We propose a notion of synthesized Web services (ASTs) to specify the behaviors of the services. Upon receiving a sequence of input messages, an AST issues multiple queries to a database and generates actions, in parallel; it...

Many organizations nowadays face the problem of accessing existing data sources by means of exible mechanisms that are both pow- erful and ecient. Ontologies are widely considered as a suitable formal tool for sophisticated data access. The ontology expresses the domain of interest of the information system at a high level of abstraction, and the r...

Recent research in the area of ontology representation for the Seman-tic Web has led to several different language proposals. Among the others, it led to the standardization of OWL, on one hand, and to the emergence of the DL-Lite family of Description Logics, on the other hand. These two outcomes mainly differ on their objective: while OWL aims to...

Recent research in the area of ontology representation for the Semantic Web has led to several different language proposals. Among the others, it led to the standardization of OWL, on one hand, and to the emergence of the DL-Lite family of Description Logics, on the other hand. These two outcomes mainly differ on their objective: while OWL aims to...

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In this paper, we present an high level architecture for emergency management systems devised in the European research project WORKPAD. Such an architecture is specifically tailored in supporting collaborative work of human operators during emergencies: different teams, belonging to different organizations, need to collaborate in order to reach a c...

One of the most interesting usages of shared conceptualizations is ontology-based data access. That is, to the usual data layer of an information system we superimpose a conceptual layer to be exported to the client. Such a layer allows the client to have a conceptual view of the information in the sys- tem, which abstracts away from how such infor...

The goal of DELOS Task 4.8 Task-centered Information Management is to provide the user with a Task-centered Information Management system (TIM), which automates user's most frequent activities, by exploiting the collection of personal documents considered as a Digital Library. In previous work we have explored the issue of managing personal data by...

In several areas, such as Enterprise Application Integration, Data Integration (5), and the Semantic Web (4), clients need to access a shared conceptualization of the intensional level of the application domain in terms to specify the access to services exported by the system. Ontologies are nowadays considered as the ideal formal tool to provide s...

A Description Logics knowledge base is constituted by two components, called TBox and ABox, where the former ex- presses general knowledge about the concepts and their rela- tionships, 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 thes...

Sommario Questo documento costituisce il deliverable DALL2 del progetto Esteem e ha lo scopo di il-lustrare l'architettura complessiva di un peer Esteem. Tale architetturà e stata sviluppata nel corso del progetto con il contributo di tutti i partner e presenta una struttura modulare. In particolare, nel documento, viene fornita una descrizione dei...

The availability of vast amounts of information on the Internet and the sharp decrease in the cost of digital storage has enabled today's desktops to become personal information archives. Desktops contain collections of work- and hobbyrelated data as well as rich collections of personal multimedia files. However, the typical lack of structure of on...

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 'intell...

One of the most interesting usages of shared conceptualizations is ontology-based data access. That is, to the usual data layer of an information system we superimpose a conceptual layer to be exported to the client. Such a layer allows the client to have a conceptual view of the information in the sys- tem, which abstracts away from how such infor...

We study the notion of update of an ontology expressed as a Description Logic knowledge base. Such a knowledge base is constituted by two components, called TBox and ABox. The former expresses general knowledge about the concepts and their relationships, whereas the latter describes the state of af- fairs regarding the instances of concepts. We inv...

Data integration is the problem of combining data residing at different sources, and providing the user with a virtual view, called global schema, which is independent from the model and the physical origin of the sources. Whereas many data integration systems and theoretical works have been proposed for rela- tional data, not much investigation ha...

In this article, we examine the problem of constructing a temporal data warehouse using web services. There are many important aspects in the construction of such a warehouse. Our particular contribution in this article regards the global architecture of a system that can (i) acquire specific pages from the web (ii) control page changes (iii) easil...

In this paper we describe two automatic inference mechanisms constructed around a personal ontology with the aim of providing human like assistance for form-filling. This is part of the wider vision of DELOS Task 4.8 Task-centered Information Management, which aims to create a more activity or task-focused interaction environment for users, taking...

Data integration aims at providing the user with a virtual, integrated and reconciled view of data coming from autonomous, heterogeneous and dis- tributed data sources. The user interacts with the system by means of this view, called global schema. In particular, he poses queries to the system in terms of the global schema, and obtains the answers...

We propose a new methodology, a language and tools for the design and construction of Web data ware- houses. Our approach is Service Oriented, in that our framework makes an extensive use of Web Ser- vices and semi-structured data (XML) to define the data structures, the services and the connections be- tween them. We present an experimental versio...

Today's fast and continuous growth of large business organizations enforces an increasing need in integrating and sharing large amounts of data, coming from a number of heterogeneous and dis- tributed data sources. Thus, during the last decade, research and business community interest has migrated from DataBase Management Systems (DBMS) to data int...

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-MASTR...

Ontologies provide a conceptualization of a domain of interest. Nowa-days, 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 repos-itories is becoming more and more popular...

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 ré...

The relational model has recently been extended to so-called K-rela-tions in which tuples are assigned a unique value in a semiring K. A query lan-guage, denoted by RA + K , similar to the classical positive relational algebra, al-lows for the querying of K-relations. We study the completeness of RA + K in the sense of Bancilhon and Paredaens (BP)...