Exploring privacy for ubiquitous computing: Tools, methods and experiments
Mika Raento

Ubiquitous computing is about making computers and computerized
artefacts a pervasive part of our everyday lifes, bringing more and more
activities into the realm of information. The computationalization,
informationalization of everyday activities increases not only our
reach, efficiency and capabilities but also the amount and kinds of data
gathered about us and our activities. In this thesis, I explore how
information systems can be constructed so that they handle this personal
data in a reasonable manner.

The thesis provides two kinds of results: on one hand, tools and methods
for both the construction as well as the evaluation of ubiquitous and
mobile systems---on the other hand an evaluation of the privacy aspects
of a ubiquitous social awareness system. The work emphasises real-world
experiments as the most important way to study privacy. Additionally,
the state of current information systems as regards data protection is
studied.

The tools and methods in this thesis consist of three distinct
contributions. An algorithm for locationing in cellular networks is
proposed that does not require the location information to be revealed
beyond the user's terminal. A prototyping platform for the creation of
context-aware ubiquitous applications called ContextPhone is described
and released as open source. Finally, a set of methodological findings
for the use of smartphones in social scientific field research is
reported. A central contribution of this thesis are the pragmatic tools
that allow other researchers to carry out experiments.

The evaluation of the ubiquitous social awareness application
ContextContacts covers both the usage of the system in general as well
as an analysis of privacy implications. The usage of the system is
analyzed in the light of how users make inferences of others based on
real-time contextual cues mediated by the system, based on several
long-term field studies. The analysis of privacy implications draws
together the social psychological theory of self-presentation and
research in privacy for ubiquitous computing, deriving a set of design
guidelines for such systems.

The main findings from these studies can be summarized as follows: The
fact that ubiquitous computing systems gather more data about users can
be used to not only study the use of such systems in an effort to create
better systems but in general to study phenomena previously unstudied,
such as the dynamic change of social networks. Systems that let people
create new ways of presenting themselves to others can be fun for the
users---but the self-presentation requires several thoughtful design
decisions that allow the manipulation of the image mediated by the
system. Finally, the growing amount of computational resources available
to the users can be used to allow them to use the data themselves,
rather than just being passive subjects of data gathering.