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Situation dependent services are services that significantly depend on the user's context. Considering the indiv idual needs, such services are regarded to be more beneficial to the customer than non-individual services. In this paper we present a conceptual framework and characterise a service platform for the cooperative development of situation dependent(More)
Current mobile business models for mobile commerce do not seem promising with regard to substantial revenue streams for mobile network operators as well as mobile service providers. Today's settings require customers to " invest " into data transmission before being able to enter a mobile service, i.e. they are forced to pay for all data transmitted(More)
The optical signatures of Mg-related acceptors in GaN have been revisited in samples specifically grown on bulk GaN templates, to avoid strain broadening of the optical spectra. Bound-exciton spectra can be studied in these samples for Mg concentrations up to [Mg] approximately 2 x 10(19) cm(-3). Contrary to previous work it is found that instabilities in(More)
Digital Video Broadcasting (DVB) using the same terrestrial infrastructure (DVB-T) as traditional analogue television has become a mature technology with a growing number of users. Different activities have been started (e.g. DVB-H) in order to apply that infrastructure for distributing multimedia content and interactive services to mobile devices. DVB(More)