Information Technology Reference
In-Depth Information
Hardware components of the Satire architecture include
MICAz sensor nodes
Access motes
MICAz motes were selected as suitable sensor nodes for the Satire prototype imple-
mentation. Other platforms, which also can be used, are MICA2dot, Tmote Sky,
and Pluto nodes. MICAz nodes serve as sensing , local storage , reduced processing ,
and communication elements, with solid energy supply . Sensing implies usage of
acceleration and GPS sensors, in order to capture user's mobility patterns. Data
sampling requires 50 samples per second rate for 2-axis accelerometer, and 1 byte
for sample representation. Node's flash memory can satisfy data recording require-
ment for about 6 h. Information processing in the nodes is minimal because of the
unlimited data processing power, after the upload. Sensor nodes use wireless com-
munication for data upload through the access motes. Power supply is in the form
of two AA batteries per node which can be replaced with Lithium batteries to
extend the node's lifetime.
The Satire system is not aiming to provide continuous care at all times.
Continuity should be achieved by collecting information from different sources
such as instrumentation in the person's home, office, and garments. The access
motes are used to provide the necessary support for this feature. MICAz motes,
with reduced capabilities, serve as base stations or access motes between the sensor
nodes and PCs.
User's vicinity to access mote (connected to a PC) enables logged data upload
to a private repository associated with a person. Further, the uploaded data is used
for user's activities reconstruction. That also enables person's clinical history
The software architecture implements a heterogeneous system enabled for rapid
changes' tracking due to new hardware facilities, new sensor modalities, and new
appliances. In this case, the architecture of PC with attached access mote can be
split in several layers:
The application layer (4th)
The parsing layer (3rd)
The interpretation layer (2nd)
The USB/Serial port layer (1st)
On the other hand, software on motes includes
The application layer (4th)
The sensor layer (3rd, 2nd, and 1st)
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