1,106 research outputs found
Reasoning & Querying – State of the Art
Various query languages for Web and Semantic Web data, both for practical use and as an area of research in the scientific community, have emerged in recent years. At the same time, the broad adoption of the internet where keyword search is used in many applications, e.g. search engines, has familiarized casual users with using keyword queries to retrieve information on the internet. Unlike this easy-to-use querying, traditional query languages require knowledge of the language itself as well as of the data to be queried. Keyword-based query languages for XML and RDF bridge the gap between the two, aiming at enabling simple querying of semi-structured data, which is relevant e.g. in the context of the emerging Semantic Web. This article presents an overview of the field of keyword querying for XML and RDF
Web and Semantic Web Query Languages
A number of techniques have been developed to facilitate
powerful data retrieval on the Web and Semantic Web. Three categories
of Web query languages can be distinguished, according to the format
of the data they can retrieve: XML, RDF and Topic Maps. This article
introduces the spectrum of languages falling into these categories
and summarises their salient aspects. The languages are introduced using
common sample data and query types. Key aspects of the query
languages considered are stressed in a conclusion
IVOA Recommendation: IVOA Support Interfaces
This document describes the minimum interface that a (SOAP- or REST-based)
web service requires to participate in the IVOA. Note that this is not required
of standard VO services developed prior to this specification, although uptake
is strongly encouraged on any subsequent revision. All new standard VO
services, however, must feature a VOSI-compliant interface.
This document has been produced by the Grid and Web Services Working Group.
It has been reviewed by IVOA Members and other interested parties, and has been
endorsed by the IVOA Executive Committee as an IVOA Recommendation. It is a
stable document and may be used as reference material or cited as a normative
reference from another document. IVOA's role in making the Recommendation is to
draw attention to the specification and to promote its widespread deployment.
This enhances the functionality and interoperability inside the Astronomical
Community
Development of Use Cases, Part I
For determining requirements and constructs appropriate for a Web query language, or in fact
any language, use cases are of essence. The W3C has published two sets of use cases for XML
and RDF query languages. In this article, solutions for these use cases are presented using
Xcerpt. a novel Web and Semantic Web query language that combines access to standard Web
data such as XML documents with access to Semantic Web metadata
such as RDF resource
descriptions with reasoning abilities and rules familiar from logicprogramming.
To the
best knowledge of the authors, this is the first in depth study of how to solve use cases for
accessing XML and RDF in a single language: Integrated access to data and metadata
has been
recognized by industry and academia as one of the key challenges in data processing for the
next decade. This article is a contribution towards addressing this challenge by demonstrating
along practical and recognized use cases the usefulness of reasoning abilities, rules, and
semistructured
query languages for accessing both data (XML) and metadata
(RDF)
Implementation of metadata for OmniPaper RDF prototype
Information Society Technologies (IST) funded OmniPaper project investigates efficient ways for access to distributed and heterogeneous digital news archives using state-of-the-art technologies such as RDF, XTM and SOAP. An approach taken is to create small prototypes based on each of them. This paper presents the first stage of the prototype development, particularly of RDF approach, including analysis on existing news text format standards and metadata vocabularies, definition of metadata elements for OmniPaper, implementation of application profile and RDF schema and development of the RDF prototype in a web-based RDF specific application. The elaborated analysis shows that Dublin Core Metadata Element Set has to be a principal vocabulary to implement the OmniPaper application profile as it provides greater interoperability. The RDF prototype provides RDF “metadatabase” with searchable interface for simple and advance search on the defined metadata elements
Survey over Existing Query and Transformation Languages
A widely acknowledged obstacle for realizing the vision of the Semantic Web is the inability
of many current Semantic Web approaches to cope with data available in such diverging
representation formalisms as XML, RDF, or Topic Maps. A common query language is the first
step to allow transparent access to data in any of these formats. To further the understanding
of the requirements and approaches proposed for query languages in the conventional as well
as the Semantic Web, this report surveys a large number of query languages for accessing
XML, RDF, or Topic Maps. This is the first systematic survey to consider query languages from
all these areas. From the detailed survey of these query languages, a common classification
scheme is derived that is useful for understanding and differentiating languages within and
among all three areas
Implementation of a knowledge discovery and enhancement module from structured information gained from unstructured sources of information
Tese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 201
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