Position Management für ortsbezogene Community-Dienste

In Location-based Community Services (LBCSs) mobile users
interchange and correlate their spatial positions, for example, in
order to find out which other community members are currently
staying nearby. The so-called position management is responsible
for the transmission, analysis, processing and access control of
position information, which is directed along a corresponding
supply chain. The supply chain spans from the mobile device of the
target person, where the position is derived, for example, by GPS,
via intermediaries like the location or LBS provider, to the domain
of the user. Community services pose special requirements on
position management, which can be coarsely divided into the fields
privacy protection and efficiency: First, the target person must be
able to control by who and under which circumstances her position
information is accessed. To guarantee that, it must be possible to
anonymize the position data with respect to the location and LBS
provider, for which so far no technique exists that is suited for
community services. Also, the target person must be able to
authorize requests to access her position in an easy and socially
acceptable fashion. Second, concepts for efficiently realizing
so-called proactive multi-target LBCSs are needed. These services
are automatically triggered as soon as two or more target person
have entered into a certain pre-defined spatial constellation. An
example is buddy tracking, which automatically detects when two
persons have approached each other below a certain proximity
distance. The technical problem to solve is the frequent
transmission of position information over the scarce air-interface
and the associated energy consumption at the mobile terminal of the
target person. This dissertation develops new concepts in both of
the sketched fields and shows their feasibility based on numerous
simulations and analytical reflection. Also the TraX-platform is
presented, which practically implements the developed concepts.