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In this paper, we present <i>Railroad</i>, a data dissemination architecture for large-scale wireless sensor networks. Railroad system proactively exploits a virtual infrastructure called <i>Rail</i>, which is an area where all the metadata of event data are stored. There is only one Rail in the network and it acts as a rendezvous area of the events and the(More)
— This paper proposes a novel MAC protocol for sensor networks which is energy efficient and has a good performance as well. Energy is the most important resource in battery-operated sensor networks. Sensor nodes need the wireless network interface to forward data and it has to be always awake to handle possible traffics. This occupies most energy wastes in(More)
The operation of a sensor node is limited by the initially equipped battery which is hard to be recharged or replaced. Thus reducing unnecessary energy consumption is one of the most important requirements. Most energy waste is from the always-on wireless interface and many new MAC protocols have been suggested to solve the problem. However, they sacrifice(More)
We describe F-TCP, a new TCP for file transfer in high bandwidth-delay product networks. TCP is not suitable for file transfer application in high bandwidth-delay product networks. There needs a protocol that should not take away too much bandwidth from standard TCP flows while utilizing the full bandwidth of high-speed networks. This paper presents another(More)
In this paper we present a system, called U-interactive, that provides spontaneous interactions between human and surrounding objects in heterogenous ubiquitous computing environments. Our U-interactive system introduces a virtual map, which contains interactive objects around a user in each ubiquitous environment. In the virtual map, each interactive(More)