Nokia Internet Tablet based context aware computing platform

Type: Semester thesis
Students: Samuel Welten, Pascal Sachs
Advisor: Marc Bächlin, Johannes Winkelmann
Project: DAPHNet

Nowadays devices usually used in research for context aware computing are very expensive because they are only produced in small production series. Therefore it would be interesting to use a commercially available device for this purpose.

In this thesis the ability of the Nokia Internet Tablet N770 and N800 to serve as a context aware platforms were determined. Therefore the already existing Device Reader software was ported to both devices. As this software had only a command line interface, but the Nokia Internet Tablet features a touch screen, a graphical user interface was programmed to make use of the new possibilities.
The software was extended by an annotation possibility, meaning the user can annotate the current activity using the touch screen. The annotation data is stored together with the sensor signals using the Device Reader framework.
Furthermore an algorithm for sound based context awareness was implemented. It records the audio data from the built-in microphone, calculates features of the signal and uses either a Bayes or a NCC classifier to determine the location of the device.
Benchmarks with the Nokia Internet Tablet showed the capabilities and weaknesses of the appliance. From the results one could see that the N800 is fast enough to do real time sound processing and even more sophisticated algorithms than the one  implemented could run on it. The battery life time is up to 18h hours of countinuous sensor data recording, which allows a day long recording.

Tests with the sound based location recognition algorithm resulted in a recognition rate of about 78% for five different locations. Disappointing was that it couldn't run on the N770, due to an error in the communication of the DSP and the gstreamer library, which didn't allow to record sound data over a long time.
As a conclusion one can say that the N800 can be used as a context aware platform and has a long battery lifetime. The limit of the device is the lack of wired communication possibilities. After all it is possible to use scientific software for context awareness on a commercially available device.