An Extensible Technique for Content Adaptation in Web-Based Information Systems

Abstract

Adaptive Web information systems need to exploit information about the context of the chent in order to dehver, in an appropriate way, relevant information. In this paper, we present a general approach to this problem that is able to handle heterogeneous context information and different coordinates of adaptation. The approach is based on a general notion of profile that can be used to represent a variety of contexts at different level of details. Client profiles, possibly expressed in different formats, are wrapped and translated into such a general representation. The analysis of profiles drives the generation of an interface configuration. A configuration specifies, at the various layers of a Web based Information System (content, navigation and presentation), how to build a response that meets the requirements of adaptation of the profile. We describe architecture and functionality of a prototype implementing such adaptation methodology and illustrate practical examples of use of the prototype.Keywords: Adaptive Information Systems, Context awareness, Data Intensive Web Sites, Heterogeneous profiles INTRODUCTIONAn ever increasing number of mobile devices, such as PDAs and next generation phones, can be deployed today to provide everywhere and any time access to the Web. This scenario presents a number of challenges, especially when it comes to data-intensive applications, mainly because these devices offer limited computing capabilities. It follows that a novel and fundamental requirement of modern Web based Information Systems is the ability to adapt and personalize content delivery according to the context of the client (a human being or an application). There 108 Roberto De Virgilio and Riccardo Torloneis no accepted definition of context, but the term is a usually adopted to indicate "a set of attributes that characterizes the capabilities of the access mechanism, the preferences of the user and other aspects of the context into which a Web page is to be delivered" (W3C Device Independence Working Group, 2003). These may include the access device, the network QoS, the user preferences, the location, and so on.Many approaches have been proposed to the problem of the design and the implementation of an adaptive Web based information system (Bickmore et al, 1999;Ceri et al, 2000;Ceri et al, 2003; KieBling, 2002; Leubner and Kie, 2002;Gu and Helal, 2004;Pastor et al, 2003;Schwabe et al, 1996). However, they are often specific solutions, suited only for predefined adaptation requirements (usually device characteristics and user preferences) and hardly reusable for adding new adaptation functionality to existing systems. In these approaches a relevant problem that has received little attention is the large heterogeneity of formats used to express context information: text files in ad-hoc format, HTTP headers, XML files over specific DTD's, RDF (Lassila and Swick, 1999;Brickley and Guha, 2003), CC/PP (Klyne et al, 2004).In our study, we focus our attention,on the large category of data intensive Web ...