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Tienari H (2002)
Modular and intelligent architecture for context-aware telephony services.
M.Sc. thesis, Department of Electrical Engineering, University of Oulu, Finland (in Finnish).
Context-aware services perceive everyday circumstances of users, for example
their location. Context can be utilised among other things in interpersonal
communications in the form of smart context-aware communication services.
For example if a cellular phone rings during a symphony concert or in an
important meeting, it is generally considered as improper behaviour in our
culture. If a communication device automatically notices its user's context,
it can adapt accordingly and an awkward situation can be avoided.
Communications become more effective as the number of unsuccessful contact
attempts decreases. In addition to location information, the utilised
context can be for example knowledge of a user's current social situation or
his/her physiological state.
In practice context information is gathered by different sensors that may
reside in the user's terminal or in the environment. Typically the
components that perceive the physical world are not part of a certain
service application and thus not under its control. The system by its basic
nature is distributed to the network. Often components are independently
mobile, behind slow wireless connections, and sometimes some of them are
unavailable due to network breakdowns or other failures. This all places
certain technical distribution challenges to the system. There is no sense
in that every service in use would require its own sensors and context
delivery mechanism. To optimise the use of a sensor and information delivery
resources, and to ease the development of services, it is a necessity that
services share common context sensing and delivery infrastructure.
In this thesis, some existing architectural solutions are evaluated, and
then a new experimental system is developed as an environment in which we
try to enhance their weaknesses. Especially we try to ease the development
of new services by moving responsibility of context handling from services
to the context server, by offering context handling user interfaces for the
service applications as a mobile code, and generally aiming at as modular an
architecture as possible. The architecture and the platform are tested in
practice by building a simple context-aware message interchange service. The
gained findings are very encouraging.