Information Technology Reference
Each device in the ubiquitous framework has to be able to give feedbacks
about the elaboration state, to alert the user to input data, acknowledge the
user for received input or tell the user that the input is wrong .
4.3.2 Aural outputs
In current interfaces, aural perception is integrated with visual stimuli to
make easier the dialogue between man and machine .
Different sounds are used to alert the user on inserted wrong data or about
an ongoing computation and so on. In general, sound enriches the informa-
tion exchanged through the interface [10,15].
Aural perception is crucial in all the application where the user attention
is not focused on the screen. Some examples are medical applications, flight,
transportation and video surveillance where the attention decreases with time.
Finally, blind people can navigate structured data as web pages using suitable
software called screen readers [11,16].
4.3.3 Haptic outputs
In the last three decades many haptic devices have been developed but only a
few are available because they are very expensive . When low-cost haptic
devices can be integrated in UC frameworks, they will be very useful above
all for seeing-impaired people . Finally, haptic devices can be suitably
integrated in virtual reality .
5.1 Relevance for ubiquitous computing technologies
Modern computers are no more tools for technicians alone. More and more
people use the PC due to lowering prices and software applications that can
be used efficiently even by unskilled people. Easy-to-use software relies on
GUIs and their usability.
Usability is defined by ISO norm 9241 as 'an important consideration in the
design of products because it is concerned with the extent to which the users of
products are able to work effectively, efficiently and with satisfaction'.
Designing usable systems has been a crucial topic in software evolution.
When technology was not mature, it was very difficult and expensive to
produce usable software. In the field of UC, designers have to pay attention
to usability because UC technologies can modify the current usability
In this respect, the context-aware systems are very interesting. These
are software architecture that can perceive the surrounding environment