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More and more people combine several purposes with travelling, such as business, leisure, entertainment, and education. Such people may not have time to pre-plan a travel schedule in detail. They need location-aware information about the destination domain and expect in-dividualised information and services. The EU funded research project CRUMPET addresses(More)
Recent developments in mobile communication and personal computer technology have laid a new foundation for mobile computing. Performance of the data communication system as seen by an application program is a fundamental factor when communication infrastructure at the application layer is designed. This paper provides results of performance measurements of(More)
– In this paper we present results of measurements on the performance of GSM HSCSD and GPRS data transmission. We used a measurement tool that we have developed to study the performance of various wireless links as perceived by nomadic applications using the TCP protocol. The results show that in stationary connections the throughput and response time were(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)
Modern portable computers and wireless connections over cellular telephone networks have created a new platform for distributed information processing. We have designed a communication architecture that makes it possible to exploit the existing TCP/IP communication protocols but that also takes into account speciic features of cellular links. Our(More)
A high variety of Quality of Service (QoS) in data transmission over wireless networks creates challenges that have not been adequately addressed in today's Internet-based services. Whereas today's distributed applications may result in treating rapid and extreme changes in QoS as failures, in the nomadic environment comprising wireless data communications(More)