Information Technology Reference
In-Depth Information
Personal Assistant - its task is to help the user in specifying the service requests sent to
the system, accomplish the communication with the InfoStations' software, receive and
visualise the service requests' results to the user, etc. Moreover the assistant can provide
information needed for the personalisation of services (based on information stored in
the user profile) and/or for the synchronisation of scenario execution;
Graphical User Interface (GUI) - its task is to prepare and present the forms for setting
up the service requests, and visualise the corresponding results received back from the
system.
Fig. 4. The layered system architecture
3.4 Agent-oriented middleware architecture
The main implementation challenges within this system are related to the support of
distributed control, as the system should be capable of detecting all relevant changes in the
environment (context-awareness) and according to these changes, facilitate the service
offerings in the most flexible and efficient manner (adaptability). The system architecture
presented in the previous section is implemented as a set of cooperating intelligent agents.
An agent oriented approach has been adopted in the development of this architecture in
order to:
Model adequately the real distributed infrastructure;
Allow for realisation of distributed models of control;
Ensure pro-active middleware behaviour which is quite beneficial in many situations;
Use more efficiently the information resources spread over different InfoStations.
Moreover, the agent-oriented architecture can easily be extended with new agents (where
required) that cooperate with the existing ones and communicate by means of a
standardized protocol (in this case the FIPA -Agent Communication Language (ACL)
[FIPA,2002]). Indeed the InfoStations and InfoStation Centre exist as networks of
interoperating agents and services, with the agents fulfilling various essential roles
necessary for system management. Within each of these platforms, agents take
responsibility for selecting and establishing a client-server cross-platform connection,
