Content adaptation is defined as the process of selection, generation, or modification of content which include text, images, audio, video, navigation, interaction, any object within a Web page, and associate service agreement (Forte, Claudino, de Souza, do Prado, & Santana, 2007) to suit user’s context (TellaSonera, 2004). With the proliferation of mobile devices such as personal digital assistants (PDA) and smart mobile phones which have the capability of accessing the Internet anytime and anywhere, there is an increasing demand for content adaptation to provide these devices with appropriate content that is aesthetically pleasant, easy to navigate, and achieve satisfying user experiences. This article first provides an overview of frameworks and techniques in Web content adaptation that are being developed to extend Web applications to non-desktop platforms. After describing general adaptation techniques, this article focuses particularly on the adaptation requirements for e-learning systems, especially when they are accessed through mobile devices.
According to Bickmore and Schilit (1997), one straightforward method is to re-author the original Web content. Manual re-authoring can be done, but obviously is the most ineffective way and requires that the Web pages must be accessible for re-authoring. This sometimes poses some practical constraints. However, the underlying principles and questions that are faced are identical for both automatic and manual re-authoring: What are the strategies used to re-author the pages? What are the strategies used to re-designate the navigations? What presentation styles can be achieved? These are the questions facing any content adaptation process. The underlying principle is to isolate and distinguish the Web content objects, presentation objects, navigation objects, and interactive objects for desktop publication, and re-map them into other device-capable objects. Figure 1 shows such a re-mapping process. Once the strategies have been defined and the process is matured, manual re-authoring can be converted into automated re-authoring through HyperText Transfer Protocol (HTTP) proxy server or server-side techniques such as Common Gateway Interface (CGI), or Servlet or client-side scripting. The re-authoring approach can either be mobile device-specific or tailored to multiple classes of devices. For multiple devices re-authoring, transformation-styles sheets (XSLT) and cascading-styles sheets (CCS) can also be used.
Key Terms in this Chapter
Resource Description Framework (RDF): RDF is a language for representing information about resources in the World Wide Web.
Xpointer: Xpointer is the XML Pointer Language that defines an addressing scheme for individual parts of an XML document.
CGI: Common Gateway Interface is a standard protocol for users to interact with applications on the Web servers.
XML: Extensive Markup Language is a W3C standard similar to HTML, but allows creators to create their own tags.
Annotation: A technique for content adaptation; special tags are added onto the HTML page to allow browser to operate in a pre-defined function.
Proxy: A server that sits between the Web server and the client to provide protection and filtering
URL: Universal resource locator. URL identifies the address location of the web pages.
XSL: Extensive Stylesheet Language is a W3C standard which specifies how a program should render XML document data.
Xpath: XPath is a language for addressing parts of an XML document. It is used together with XSLT and XPointer.
Transcoding: A technique for content adaptation by modifying the incoming and outgoing HTTP stream
HTTP: HyperText Transfer Protocol is a protocol for transferring requests and files over the Internet.
Apache: An open-source HTTP server for operating systems including UNIX and Windows NT; a project supported by Apache Software Foundation
HTML: HyperText Markup Language is the language used to create Web content.