Alexander Zipf

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The OpenStreetMap (OSM) project, founded in 2004, has gathered an exceptional amount of interest in recent years and counts as one of the most impressive sources of Volunteered Geographic Information (VGI) on the Internet. In total, more than half a million members had registered for the project by the end of 2011. However, while this number of contributors(More)
The OpenStreetMap (OSM) project is a prime example in the field of Volunteered Geographic Information (VGI). Worldwide, several hundred thousand people are currently contributing information to the ―free‖ geodatabase. However, the data contributions show a geographically heterogeneous pattern around the globe. Germany counts as one of the most active(More)
The adaptation of mobile services to context specific parameters provides great potential for developing enhanced and more user friendly systems. In this article we argue that in addition to technical issues (display size, bandwidth, etc.) and user centred factors (demographics, preferences, etc.) especially situational aspects (e.g. location) need to be(More)
“Is E-Commerce Dead, Past Its Prime, or Just Resting?” This is the title of a recent call for papers for the Journal of IT Theory and Application. The special issue aims to discuss the problems of unfulfilled business forecasts and related stock market plunges. However, despite these problems, online transactions are increasing— at least in some sectors,(More)
The vision of nomadic users having seamless, worldwide access to a range of tourist services seems within reach, within only a few years from now. While much of the underlying technology is already available, there are challenges with respect to usability that need intelligent solutions. CRUMPET has realized a personalized, location-aware tourism service,(More)
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