Ambient Intelligence Through Agile Agents - Ambient Intelligence for Scientific Discovery - page 304

Each node in a WSN has a need for discrete and unconscious maintenance.
Failure in any part of the network should be dealt with without requiring the
involvement of every node. It is the necessity for such system reactions to un-
expected and unforeseen events such as failure that acts as the catalyst for
autonomic wireless sensor networks.
It is thus clear that instilling a WSN and its nodes with autonomic properties
is not only valuable but also vital in order to work with such large and dynamic
systems. System self-management using an autonomic and multi-agent based
approach is we believe the most appropriate means for administrating such large,
complex,dynamic and distributed systems reliably and eciently.

5.3 µ AgentFactory

AgentFactory (AF) began its development journey as a SmallTalk implementa-
tion. Following this a Java-based version was developed. Since this was written
in Java it was executable on any machine capable of running a JVM. Today
we have devices so small, both physically and computationally that the mere
thought of having a JVM hosted on them is ridiculous. Even Suns recent effort
to shrink the JVM to a Micro Edition has proved ineffective for certain devices.
In order to port AF to a device incapable of hosting a JVM we began to
look at various devices and possible ways of implementing AF on them. For our
purposes we selected the Mica2 platform developed at University of California,
Berkeley. See Fig. 9 for a picture of this platform.
These devices have both a wireless communication capability and the ability
to execute user defined programs. The programs must fit into 128K of instruc-
tion memory and 4K of variable memory. Various sensor boards can be attached
to this platform. They mate with it through the long white rectangular connec-
tor on the side of the board. Such boards can contain sensors for light, heat,
sound, humidity and acceleration. There is also an expansion board that allows
users to design their own sensors and attach them to the board. Indeed we have
successfully created programs that use chemical sensors which are an extension
to the basic sensor suite.
When endeavoring to port a large framework like AF it is important to adopt
an incremental porting strategy. Embedded systems, like the Motes, are by their
nature notoriously dicult to program and debug. With this in mind, we began

Fig. 9. Mica2 Mote Platform.