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—For AC railway power supply systems with a different frequency than the public grid, high-voltage AC (HVAC) transmission lines are common, connected to the catenary by transformers. This paper suggests an alternative design based on an HVDC (High Voltage DC) feeder, which is connected to the catenary by converters. Such an HVDC line would also be(More)
The simplicity of the basic client/server model of Web services led quickly to its widespread adoption, but also to scalability and performance problems. The technological response to these problems has been the development of technology for the creation of surrogates for Web servers, starting with simple proxy caches and reverse proxies, and leading more(More)
The Helmholtz equation (HE) describes wave propagation in applications such as acoustics and electromagnetics. For realistic problems, solving the HE is often too expensive. Instead, approximations like the parabolic wave equation (PE) are used. For low-frequency shallow-water environments, one persistent problem is to assess the accuracy of the PE model.(More)
The experiment BAROC (Baltic Acoustics on Rocky Outcrops) was performed in May 2002. Analysis and modelling of part of the received data are reported here, concerning transmission loss and reverberation in a shallow-water area south of Stockholm. LFM pulses were transmitted in two directions with frequency content between 500 and 5500 Hz. In both directions(More)
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