Newsletter Discussion

Abstract

It is expected that the influence of XML on digital libraries is certain to increase. The RDF/XML format is the most common implemented serialization of RDF in libraries, making it ideal for RDF interchange between applications. For librarians, who are interested in RDF format, XSLT provides a viable solution for converting XML to RDF/XML format.

Knowledge Management in Digital Libraries

From XML to RDF

Over the past decade, many technological innovations related to libraries have been made; of all of them, XML (Extensible Markup Language) generated the most excitement, transforming the way how information is managed and delivered. XML is definitely significant because it eases the searching and sharing of resources that are stored in different formats. Historically, libraries have served as centralized repositories of information. They purchased books, journals, films and other information resources on physical media, and patrons found what the library owned by consulting a catalogue that listed holdings. But since the access to the Internet has been widespread, the access to remote electronic resources became possible.

The information has to be structured in a meaningful way, in order to be displayed and searched. This means that information providers have to agree on standards for the encoding of electronic documents, in order for them to be retrieved in a uniform way. When the information is stored in XML, it is possible to share and combine data in a manner that would not be possible otherwise. The more libraries use XML, the more implementations become reasonable. Additionally, it can be expected that the influence of XML on digital libraries is certain to increase.

RDF (Resource Description Framework) was designed by the W3C as a general metadata modelling facility; it offers many features which make it an ideal companion to XML data. In many XML applications, the knowledge is stored in XML documents in a database or repository. Libraries have had big success in providing access to internet resources that meet the library's selection criteria. Encoding these resources in RDF and sharing the results with internet search engines is an important contribution libraries can make to enhance their search facility service.

The RDF/XML format is a way to encode an RDF model into an XML tree. Which is the most common implemented serialization of RDF in libraries, making it ideal for RDF interchange between applications. XML can be transmitted, manipulated, and arranged relatively easily.

XSLT is a language used to transform XML documents into other XML documents, thus it can be used for getting RDF/XML. But before an XSLT stylesheet can be written, one needs to have a very good idea about what the result should look like. The examples (sample XML entries with respect to Digital Libraries) can be created and tested with a trial-version of Stylus Studio XML Professional Edition (http://www.stylusstudio.com/). For librarians, who are interested in data in RDF format, this can be a way to the solution. Of course, one should be aware that for each individual XML structure, particular XSLT stylesheets have to be created. There is no general solution which is valid for all existing XML formats.