Ubiquitous Web Applications
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Web sites are progressively evolving from browsable, readonly information repositories that exploit the web to interact with their users, to web-based applications, combining navigation and search capabilities with operations and transactions typical of information systems. In parallel, the possibility of accessing web-based contents and services through a number of different devices, ranging from full-fledged desktop computers, to Personal Digital Assistants (PDA’s), to mobile phones, to set-top boxes connected to TV’s, makes web applications ubiquitous, i.e., accessible anywhere at any time.
Ubiquitous Web Applications (UWA’s for short) reveal a number of aspects which make them different with respect to a conventional data-intensive applications, and must be taken into account throughout the whole application lifecycle, from requirements to implementation. UWA’s are executed in a Web-based environment, where the paradigm for presenting and accessing information is hypermedia-like. Thus UWA’s have a mixed nature - hypermedia and transactional, where hypertext structures and operation capabilities are strongly intertwined. In addition, the ubiquitous nature of a UWA implies that the application has to take into account the different constraints of different devices, comprising display size, local storage size, method of input and computing speed as well as network capacity. At the same time, ubiquity introduces new requirements on how the application tunes itself to the end user: each user may wish to get information, navigation patterns, lay-out, and services, that are tailored not only to his/her specific profile but also to the current situation of use, in its temporal and environmental aspects. Thus Ubiquitous Web Applications must be at the same time device-aware, user-aware, and context-of-use-aware, and require sophisticate forms of customization.
After an analysis of the novel requirements of UWA’s, this talk will focus on their impact on the design process, and will discuss problems and challenges related to modeling information and navigation structures, operations and transactions, and customization mechanisms for this class of applications.