Overview

Up to this point, we have discussed XML as a representation format for managing and interchanging structured data. We have said nothing so far about how we are able to view XML-based data on typical front-end devices.

In this chapter we will give an overview of several formats for presenting XML data, with a focus on Web and multimedia applications. First, we will discuss the attributes of data formats that serve representational and presentational purposes. We will base our discussion on results from multimedia research.

Dealing with several formats is of interest to multipurpose Web publishing providing Web publishers with a means to present content on a range of client systems, such as browsers, mobile devices like PDAs, and even phones. The current standardization effort will help to provide this ability. Challenges to be solved include device independence, reusability of content, and encodings that meet the limitations presented by network transfer capabilities. The W3C has made important recommendations and more are expected about several formats, including HTML, XML, and CSS. All of them will be considered in this chapter.

8.1 Presentation and representation

Information system tasks

When dealing with arbitrary data in today s information systems, there are five tasks that must be supported by computer systems:

• The creation or definition of data

• The processing or manipulation of data

• The storage of that data

• The exchange of data

• The presentation of data to end users

Although each of these tasks may need a particular data format, we may reduce our discussion to exactly two...