Esprit "IT for Mobility" 26900
source of the systemís input is the set S of basic sensors. In theory,
a sensor can be just about anything: a light sensor, a microphone, a global
positioning system (GPS), a camera or even a human. In literature, this
last kind of sensor is usually referred to as a logical sensor, while the
other examples are called physical sensors. The only requirement a sensor
should comply with is that it should periodically produce a value that
resembles a measurement of a physical phenomenon in its real world context.
The formation of such a signal is a digital and unstructured sub-symbolic
value. A context description resides usually on a higher level than the
outputs of the sensors.
obvious way of plotting the sensor data is to make a graph of the sensorvalues
of time. When a sensor produces a value, this value could be considered
as a component of a vector, which has a dimensionality equal to the number
of available sensors. This leads to a second method of visualisation (the
phase space plot), in which each point in an Euclidean space could represent
this vector. Plotting this space requires that the dimension of the space
is less than - or equal to three. Thus, some sensors have to be ignored
if there are more than three sensors available.
|Example of a Time Series Plot (eight sensorvalues over
Example of a Phase Space Plot (vectorplot of three sensorvalues):
Accelerometer Output and Cue (during different activities): <click here>
|These are datasets, copied into an Excel document. The
information about the current dataset can be found in the spreadsheet itself.
They can be found at <http://foobar.starlab.net/~kristof/datasets/>
More datasets will be added soon.
See our papers for the latest experiment results and their descriptions.
|last update: 24/08/2000 by Kristof Van Laerhoven||the previous sites can still be found here and here|