1,721,105 research outputs found
Exploiting related digital library corpora with query rewriting
No full textIn this paper, we present the preliminary results of the ongoing research activity we are carrying out in the context of approximate XML query answering when the schemas of the XML documents are available. The method we propose involves a preliminary schema matching process, which automatically identifies the semantic and structural similarities between the schema elements to be used in the subsequent operation of query rewriting, in which a query written on a source schema is automatically rewritten in order to be compatible with the other useful XML documents. The proposed approach has been implemented in a web service, named XML S3MART, which is part of the open architecture proposed in the ongoing Italian CNR co-funded ECD Project
The Valid Web: un'infrastruttura XML/XSL per la gestione temporale di documenti Web
No full textIn questo lavoro presentiamo una estensione temporale del Web per il supporto e la gestione del tempo di validità, definita attraverso una infrastuttura XML/XS
Effective representation and efficient management of indeterminate dates
No full textManagement of indeterminate temporal expressions is useful in a wide range of applications, from designing and querying temporal databases to knowledge representation and reasoning in artificial intelligence. In this paper, we focus on the representation and management of indeterminate dates, corresponding to a common use of temporal indeterminacy which can be found in (historical) texts written in natural language, as in expressions like: around 1624, near the end of the fourteenth century, etc. In this context, we adapt and improve the probabilistic approach designed for the TSQL2 language and further developed by Dyreson and Snodgrass, and show how it can be effectively and efficiently adopted for the management of indeterminate dates
Codifica XML e Gestione di Informazione Temporale in Fonti Storiche Digitalizzate di Grandi Dimensioni
No full textQuesto lavoro tratta dell'impiego di tecnologie legate all'XML per applicazioni nel campo dei Beni Culturali che sfruttino la codifica di semantica temporale nella gestione di documenti storici in forma elettronica. La ricerca è inserita nel contesto di un progetto mirato alla produzione di una versione digitale XML fruibile via Internet del dizionario Repetti (XIX secolo), di grande interesse per lo studio della storia e dell'archeologia medievale della Toscana. In particolare presentiamo una proposta di classificazione e codifica uniforme delle informazioni temporali contenute in fonti testuali caratterizzate da indeterminazione e uso di granularità e calendari multipli. Tale proposta si basa sull'estensione dell'approccio probabilistico (alla TSQL2) all'indeterminazione, con l'introduzione di distribuzioni di probabilità costanti a tratti, che risultano essere corrette da unpunto di vista semantico e si prestano ad elaborazioni particolarmente efficienti.L'articolo contiene inoltre una breve descrizione di due strumenti i cui prototipi sono in avanzata fase di realizzazione: un tool di sviluppo, di uso amichevole, per l'introduzione assistita della marcatura temporale all'interno dei documenti e un sistema per la gestione della collezione di documenti XML che rende disponible tramite il Web un efficiente motore di ricerca temporale
The Valid Web
No full textThe Valid Web is a software prototype implementing temporal extensions of the World Wide Web. The temporal dimension of interest is the valid time, which represents the evolution of data with respect of the real-world (or virtual) environment they describe. The prototype consists of a Web site browsable with MS Internet Explorer 5 (Ie5), which allows the selective processing of HTML/XML documents containing historical information or temporal data. The base techniques employed in the prototype design and development, which derive from the temporal database theory, are the adoption of data timestamping andtemporal selection operators for the creation and management of Web pages, respectively
Un'infrastruttura XML/XSL per la gestione temporale di documenti e dati in ambiente Web.
No full textIn questo lavoro presentiamo una estensione temporale del Web per il supporto e la gestione del tempo di validità, definita attraverso una infrastruttura XML/XSL. Tale estensione consente la definizione esplicita di informazione temporale all'interno di pagine Web (documenti HTML o XML), i cui contenuti possono cosìessere acceduti e fruiti selettivamente in base alla loro validità. Con la soluzione proposta, agendo su di un contesto di navigazione temporale, è possibile "viaggiare nel tempo'' in un ambiente virtuale dato, attraverso un qualunque browser che riconosca il codice XML. Dal punto di vista dell'utente tale funzionalità consente, ad esempio, di ritagliare percorsi di visita personalizzata, circoscritti ad una particolare epoca, all'interno di un museo virtuale o di una biblioteca storica digitale, oppure di visualizzare l'evoluzione attraverso epoche successive di un sitoarcheologico, oppure anche di accedere selettivamente a serie storiche di dati (es. quotazioni di borsa), edizioni passate di pubblicazioni on-line e quanto altro possa essere organizzato secondo la dimensione temporale. In aggiunta a tali funzionalità dinavigazione, l'infrastruttura proposta può anche essere impiegata, in maniera immediata, per la gestione di dati semistrutturati codificati in XML, ponendo le basi per la gestione di dati temporali e lo sviluppo di linguaggi di interrogazione temporale per XML.Le estensioni del Web proposte sono state sperimentate su di un prototipo software che mostra due esempi applicativi: la realizzazione di un sito Web temporale (museo virtuale) e la gestione di dati XML temporali con funzionalità di query di tipo TSQL2
A Formal Model for Temporal Schema Versioning in Object-Oriented Databases
No full textIn this paper we present a formal model for the support of temporal schema versions in object-oriented databases. Its definition is partially based on a generic (ODMG compatible)object model and partially introduces new concepts. The proposed model supports all the schema changes which are usually considered in the OODB literature, for which an operational semantics and a formal analysis of their correct behaviour is provided. Semantic issues arising from the introduction of temporal schema versioning in a conventional or temporal database (concerning the interaction between the intensional and extensional levels of versioning and the management of data in the presence of multiple schema versions) are also considered
Evolution and Change in Data Management - Issues and Directions
Full text linkOne of the fundamental aspects of information and database systems is that they change. Moreover, in so doing they evolve, although the manner and quality of this evolution is highly dependent on the mechanisms in place to handle it. While changes in data are handled well, changes in other aspects, such as structure, rules, constraints, the model, etc., are handled to varying levels of sophistication and completeness. In order to study this in more detail a workshop on Evolution and Change in Data Management was held in Paris in November 1999. It brought together researchers from a wide range of disciplines with a common interest in handling the fundamental characteristics and the conceptual modelling of change in information and database systems. This short report of the workshop concentrates on some of the general lessons that emerged during the four days
The "XML/Repetti" Project: Encoding and Manipulation of Temporal Information in Historical Text Sources
No full textThe paper deals with the deployment of XML-related technologies in Cultural Heritage applications concerningthe encoding of temporal semantics in the digital versionof historical documents. Since written sources have oftenthe same importance as material evidence in medievalarchaeology, our approach can be applied to thedevelopment of tools for the support of archaeologicalresearch. In previous work, we developed an XML/XSLinfrastructure called “The Valid Web” for the definitionand management of historical information within Webdocuments. In this paper we describe the application andextension of such an approach to the realization of theelectronic version of Repetti's historical-geographicaldictionary of Tuscany. The extension concerns the uniformmanagement of temporal indeterminacy, the use ofmultiple calendars and granularities and the proposedsolutions have been inspired by similar research done fortemporal query languages. From the user viewpoint, theproposed XML extensions allow the addition of historicalmetainformation to the encoded text sources and their“intelligent” temporal navigation via standard Webbrowsers. The project also involves the definition ofoptimized search algorithms, storage and temporalindexing of XML-encoded Repetti's Dictionary items,implementation of a prototype. As a byproduct, also a toolfor computer-aided temporal XML-encoding of textsources will be developed to be used by Cultural Heritageoperators (e.g. archaeology researchers)
A Framework for user-driven mapping discovery in rich spaces of heterogeneous data
No full textData analysis in rich spaces of heterogeneous data sources is an increasingly common activity. Examples include exploratory data analysis and personal information management. Mapping specification is one of the key issues in this data management setting that answer to the need of a unified search over the full spectrum of relevant knowledge. Indeed, while users in data analytics are engaged in an open-ended interaction between data discovery and data orchestration, most of the solutions for mapping specification available so far are intended for expert users. This paper proposes a general framework for a novel paradigm for user-driven mapping discovery where mapping specification is interactively driven by the information seeking activities of users and the exclusive role of mappings is to contribute to users satisfaction. The underlying key idea is that data semantics is in the eye of the consumers. Thus, we start from user queries which we try to satisfy in the dataspace. In this process of satisfaction, we often need to discover new mappings, to expose the user to the data thereby discovered for their feedback, and possibly continued towards user satisfaction. The framework is made up of (a) a theoretical foundation where we formally introduce the notion of candidate mapping sets for a user query, and (b) an interactive and incremental algorithm that, given a user query, finds a candidate mapping set that satisfies the user. The algorithm incrementally builds the candidate mapping set by searching in the dataspace data samples and deriving mapping lattices that are explored to deliver mappings for user feedback. With the aim of fitting the user information need in a limited number of interactions, the algorithm provides for a multi-criteria selection strategy for candidate mapping sets. Finally, a proof of the correctness of the algorithm is provided in the paper
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