2,208 research outputs found

    The fans united will always be connected: building a practical DTN in a football stadium

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    Football stadia present a difficult environment for the deployment of digital services, due to their architectural design and the capacity problems from the numbers of fans. We present preliminary results from deploying an Android app building an ad hoc network amongst the attendees at matches at Brighton and Hove Albion's AMEX stadium, so as to share the available capacity and supply digital services to season ticket holders. We describe the protocol, how we engaged our users in service design so that the app was attractive to use and the problems we encountered in using Android

    Determination of the phase diagram of the electron doped superconductor Ba(Fe1x_{1-x}Cox_x)2_2As2_2

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    Systematic measurements of the resistivity, heat capacity, susceptibility and Hall coefficient are presented for single crystal samples of the electron-doped superconductor Ba(Fe1x_{1-x}Cox_x)2_2As2_2. These data delineate an xTx-T phase diagram in which the single magnetic/structural phase transition that is observed for undoped BaFe2_2As2_2 at 134 K apparently splits into two distinct phase transitions, both of which are rapidly suppressed with increasing Co concentration. Superconductivity emerges for Co concentrations above x0.025x \sim 0.025, and appears to coexist with the broken symmetry state for an appreciable range of doping, up to x0.06x \sim 0.06. The optimal superconducting transition temperature appears to coincide with the Co concentration at which the magnetic/structural phase transitions are totally suppressed, at least within the resolution provided by the finite step size between crystals prepared with different doping levels. Superconductivity is observed for a further range of Co concentrations, before being completely suppressed for x0.018x \sim 0.018 and above. The form of this xTx-T phase diagram is suggestive of an association between superconductivity and a quantum critical point arising from suppression of the magnetic and/or structural phase transitions

    Mediating exposure in public interactions

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    Mobile computing and public interactions together open up a new range of challenges in interaction design. To date a very gregarious model of interaction has been assumed. However, the public setting will invoke feelings of shyness and a desire to control the personal exposure associated with interactions. In this paper we discuss these issues and our initial tests of a system which affords a control beyond "engage or don't engage"
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