Information Technology Reference
In-Depth Information
important that a device does not simply drop dead when it is out of power but a timely
warning is given for recharging or battery replacement.
Application hosting device:
this class of devices has four important functions. Firstly,
to communicate with the PAN and LAN devices to collect sensor data and to send
commands to the actuators. Some data might be made available through special
networks, e.g. location data. Secondly, to communicate with the WAN services to
forward sensor data to the relevant back-end services and to process the response.
Thirdly, the local storage of data, aggregation of data and reasoning about these data.
This means that not only standardization of messages with respect to syntax (format
and coding systems) is needed but also standardization of semantics (ontologies and
vocabularies) is important. Fourthly, to interact with the user to present information or
support the user in his or her work. Since these devices interact with people and have
access to sensitive data or are able to control devices, security and privacy are
important topics. Multiple variants of interaction devices and interaction schemes are
required to take account of the user's preferences and abilities. An abstraction layer
covering information to be presented and information required from the user separating
it from the actual presentation is needed. Different interaction schemes should exist to
present this information in a way, the user is able to perceive and understand and to get
feedback from the user via a modality that fits the abilities of the user.
For stationary application-hosting devices like a computer, Set-top-box or car system
power constraints are less relevant (except for environmental reasons) but for mobile
devices like PDAs, smart phones or movable robots, power constraints are important
and timely warnings for recharging are needed.
WAN interface:
this interface connects the application-hosting devices with services
somewhere on the Internet. This includes wired or wireless access networks like ADSL,
cable, mobile (GPRS, EDGE and UMTS and future equivalents) and public wireless
networks. In-home device might use the in-home LAN interface to connect to these
external networks.
WAN services:
these back-end services of the different systems store the collected
information, forward relevant information to other services, analyse and reason about
the data and raise triggers for clients and/or care givers and other services, and fulfill a
reporting function. It is important that the dynamic configuration of a set of services
matches the developing needs of clients as well as their care givers. Important issues
for services are security with respect to access (preferably role- and task-based access
control combined with a treatment or care relationship with the patient) and privacy of
sensitive data.
It should be clear that AAL systems will vary in composition and not all functions
or components will be present in every system, it depends e.g. on the level of support a
person needs and often the system for a care giver does not have sensor or actuator
functionality. There might also be appliances consisting of sensors, reasoning functions
and actuators for feedback implemented in single device or a collection of devices
using proprietary connections. Such appliances might pass on results to other reasoning
and feedback services for aggregation using the PAN, LAN or even WAN interface.
