3 MOTIVATION AND BENEFITS
OF USING A STANDARD IN
AAL
The main-objective of applying a standard in IT-
infrastructure with special regard to medical devices
is interoperability. According to IEEE (IEEE-USA,
2005), interoperability in healthcare does not only
mean that healthcare systems must be able to com-
municate with one another, but also that they must
employ shared terminology and definitions. Imple-
mented systems should communicate in a way that
systems ”understand” each other and thus prevent the
loss of information and allow the correct interpre-
tation and evaluation of transmitted data. Standard
Committees, like the International Standards Orga-
nization (ISO), provide standards to avoid isolated
applications with their own communication structure
and terminology.
The ISO/IEEE 11073 standards define a common
core of communication functionality for medical and
personal health devices and specify the use of term
codes, formats and behaviours in a telehealth environ-
ment to favour plug & play interoperability (McCabe,
2007).
By establishing plug & play interoperability in
AAL, new sensor-network solutions can be added to
an existing manager without great effort. A standard-
ised architecture and communication structure of both
the manager and the sensor-network solution, which
represents the agent, are prerequisites. As the com-
munication flow always follows the same procedure
and transmitted data have the same bodywork, one
manager can be applied to more standard-conform
agents. So the manager always receives data in
the same format. As in AAL-technologies different
sensor-types (see table 1) are useful, which are of-
ten not provided by one manufacturer, different data-
formats have to be handled by the receiving system,
if the sensors’ communication protocols are not stan-
dard conform. Therefore the application of a common
standard would close this gap and would enable plug
& play interoperability of different sensor networks
or single sensors.
Furthermore a standardised format would be a
great advantage in AAL technologies for the im-
plementation of behaviour pattern recognition algo-
rithms and sensor data fusion.
Different Associations make an effort to spread
and refine the standards. In case of the ISO/IEEE
11073 standards the Continua Health Alliance is lead-
ing. It is a group of technology, healthcare and fitness
companies dedicated to establishing a system of inter-
operable telehealth solutions. These solutions should
foster the independence of people to better man-
age their health (Continua Health Alliance, 2009).
ISO/IEEE 11073 standardised sensor-networks can
be certified by the Continua Health Alliance.
4 APPLICATION OF ISO/IEEE
11073 TO AAL
Generally, the ISO/IEEE 11073-20601 architecture
consists of three models (parts), which interact with
each another:
• the Domain Information Model,
• the Communication Model and
• the Service Model.
The ISO/IEEE 11073 family is based on an object-
oriented systems management paradigm. Thus, data
(measurement, state, etc.) are modelled in the form
of information objects that are accessed using object
access services (IEEE Engineering in Medicine and
Biology Society, 2008b).
4.1 Domain Information Model
The Domain Information Model (DIM) defines the
bodywork of an agent as a set of objects. Their at-
tributes describe measurement data as well as ele-
ments that control the behaviour of agents. The DIM
describes a hierarchical structure that represents all
data an agent-device can communicate to a manager.
For the application of the Independent Living
Activity Hub following classes of the ISO/IEEE
11073-20601 have to be implemented:
Medical Device System (MDS). Each Agent is
represented by exactly one MDS-object. Its attributes
define product-specific information, as well as the
configuration of the agent and is primarily necessary
for the identification of the agent at the manager.
Moreover the MDS-class defines methods (services,
events) for the data-access.
Metric Class. The metric class is the base class for
numeric-, realtime-sa (sample array) and enumera-
tion class, which represent the measurement-objects
(Numeric, RealTime-SA and Enumeration).
Enumeration Class. An instance of the enumeration
class represents status information (e.g. from a sen-
sor), which is reported within an event report service.
According to the specification all measurement-
objects (sensor-event-objects) are instances of the
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