Linking Semistructured Data on the Web

Internet Computing, IEEE, 2009

E d it o r : M u n i n d a r P. S i ng h • s i ng h@ nc su.e du S h e ng r u Tu • s he ngr u@c s .uno .e du

2014

Data Integration is the problem of combining data in various data sources and providing a user with a unified view over these sources. Building an automatic data integration system that can process large, semi-structured data sources has emerged as an important problem. An automated data integration system requires automatic population of an Entity Name System (ENS). An ENS is a thesaurus for entities and is used to serve instance matching needs across data sources. Resource Description Framework (RDF) is a graph-based data model used to publish data on the Web as linked data. To build and populate an ENS over linked data, the fundamental problem of data matching needs to be solved. Traditionally, data matching concerned identifying pairs of logically equivalent entities across one or more structurally homogeneous data sources, and required a human in the loop. Additionally, most systems run on serial architectures. These assumptions cannot be expected to hold for linked data. Given...

Dke, 2007

XML has evolved as the new standard for the representation and exchange of both structured and semistructured data. XML's ability to succinctly describe complex information can also be used for specifying application meta-data. XML's popularity is evident from its use in a wide spectrum of application domains: from document publication, to computational chemistry, health care and life sciences, multimedia and ecommerce. Increasing popularity of web-based business and the emergence of web services that use XML-based descriptions in WSDL and exchange XML messages with SOAP have led to further acceptance of XML. The purpose of the second XML Data and Schema Management Workshop was to provide a forum for the exchange of ideas and experiences among the theoreticians and practitioners who are involved in design, management, and implementation of XML data management systems. It was held on 3 April, 2005 in conjunction with the 21st IEEE International Conference on Data Engineering (ICDE 2005). The workshop saw a lengthy full-day program that included 12 regular papers divided into three sessions. Many interesting discussions sparked off during the workshop among the presenters and the audience in almost any XML data management topics. This special issue of Data and Knowledge Engineering features four papers selected from the XSDM 2005 workshop based on their merits and relevance. Each of these papers is an extended and revised version of the original workshop paper and has gone through a rigorous reviewing process before being accepted for inclusion in this special issue. In the first paper entitled ''QMatch-A Hybrid Match Algorithm for XML Schemas'', Tansalarak and Claypool propose a new hybrid schema match algorithm, QMatch, that provides a unique path-based framework for harnessing traditional structural and semantic information, while exploiting the constraints inherent in XML documents such as the order of XML elements, to provide improved levels of matching between two given XML schemata. QMatch is based on the measurement of a unique quality of match metric, QoM, and a set of classifiers. They experimentally demonstrated the benefits of QMatch over existing algorithms such as Cupid. Efficient processing of XML queries is a key area of research in XML data management. The next two papers thus focus of efficient XML query evaluation. Chen et al. in their paper titled ''Index Structures for Matching XML Twigs Using Relational Query Processors'' address some of the limitations of existing XML path indices. They present a framework defining a family of index structures that includes most existing XML path indices. They also propose two novel index structures with different space-time tradeoffs effective for the evaluation of XML twig queries with value conditions. They also show how this family of index structures can be tightly integrated with a relational query processor. The next paper entitled ''Optimization of Nested XQuery Expressions with Orderby Clauses'' by Wang, Rundensteiner, and Mani, presents a technique for XQuery optimization. They propose an algebraic rewriting technique of nested XQuery expressions containing explicit ORDERBY clauses. Their technique is based on

Fifth Computer Science and Engineering …

Synthesis Lectures on the Semantic Web: Theory and Technology, 2011

This book gives an overview of the principles of Linked Data as well as the Web of Data that has emerged through the application of these principles. The book discusses patterns for publishing Linked Data, describes deployed Linked Data applications and examines their architecture.

A ‘Semantic Web’ Using Linked Data for day-to-day data transfer , 2009

The term Linked Data refers to a set of best practices for publishing and connecting structured data on the Web. These best practices have been adopted by an increasing number of data providers over the last three years, leading to the creation of a global data space containing billions of assertions - the Web of Data. In this article we present the concept and technical principles of Linked Data, and situate these within the broader context of related technological developments. We describe progress to date in publishing Linked Data on the Web, review applications that have been developed to exploit the Web of Data, and map out a research agenda for the Linked Data community as it moves forward.

A fundamental prerequisite of the Semantic Web is the existence of large amounts of meaningfully interlinked RDF data on the Web. The W3C SWEO community project Linking Open Data has made various open datasets available on the Web as RDF, and developed automated mechanisms to interlink them with RDF statements. Collectively, the datasets currently consist of over one billion triples. We believe that large scale interlinking will demonstrate the value of the Semantic Web compared to more centralized approaches such as Google Base 5. This paper outlines the work to date and describes the accompanying demonstration. A functioning Semantic Web is predicated on the availability of large amounts of data as RDF; not in isolated islands but as a Web of interlinked datasets. To date this prerequisite has not been widely met, leading to criticism of the broader endeavour and hindering the progress of developers wishing to build Semantic Web applications. Thanks to the Open Data movement, a va...

The term linked data is entering into common vocabulary and, as most interests us in this instance, into the specific terminology of library and information science. The concept is complex; we can summarize it as that set of best practices required for publishing and connecting structured data on the web for use by a machine. It is an expression used to describe a method of exposing, sharing and connecting data via Uniform Resource Identifiers (URIs) on the web. With linked data, in other words, we refer to data published on the web in a format readable, interpretable and, most of all, useable by machine, whose meaning is explicitly defined by a string of words and markers. In this way we constitute a linked data network (hence linked data) belonging to a domain (which constitutes the initial context), connected in turn to other external data sets (that is, those outside of the domain), in a context of increasingly extended relationships. Next is presented the Linked Open Data cloud (LOD), which collects the open data sets available on the web, and the paradigm of its exponential growth occurring in a very brief period of time which demonstrates the level of interest that linked data has garnered in organizations and institutions of different types.

2001

XML is increasingly being adopted for information publishing on the World Wide Web. However, the underlying data is often stored in the relational databases. Some mechanism is needed to convert the relational data into XML data. In this work, we employ a semantically rich semistructured data model, the Object-Relationship-Attribute model for semistructured data, as a middleware to support the schema conversion from semantically enriched relational schema to XML Schema. This approach allows us to handle the translation of a set of related relations and to distinguish attributes of relationship types from attributes of object classes, multivalued attributes, and different types of relationships such as binary, n-ary, recursive and ISA. The resulting XML structures are able to reflect the inherent semantics and implicit structure in the underlying relational database. We also show that the appropriate use of references is able to avoid unnecessary redundancy and the proliferation of disconnected XML elements.

2008

Nowadays, many users use web search engines to find and gather information. User faces an increasing amount of various semi-structured information sources. The issue of correlating, integrating and presenting related information to users becomes important. When a user uses a search engine such as Yahoo and Google to seek a specific information, the results are not only information about the availability of the desired information, but also information about other pages on which the desired information is mentioned. The number of selected pages is enormous. Therefore, the performance capabilities, the overlap among results for the same queries and limitations of web search engines are an important and large area of research. Extracting information from the web data sources also becomes very important because the massive and increasing amount of diverse semi-structured information sources in the Internet that are available to users, and the variety of web pages making the process of information extraction from web a challenging problem. This paper proposes a framework for extracting, classifying and browsing semi-structured web data sources. The framework is able to extract relevant information from different web data sources, and classify the extracted information based on the standard classification of Nokia products.