26,446 research outputs found

    Planning and Design Strategies for Sustainable Urban Development

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    In order to create high impact low-carbon architecture it is necessary to address issues at the urban scale. This paper reviews methods adopted in the UK, Hong Kong and America and develops a series of themes that should be incorporated in modern city development strategies to produce green and sustainable outcomes. These are concerned with: planning policies and building regulations; neighborhood and site planning; and building design. Underlying themes which must be incorporated are connected to: building façade, systems design and operation; energy demand and supply; transportation systems; water supply and use; and wastes/pollution issues. To achieve success a number of support mechanisms are needed including strategic and infrastructure development, implementation of assessment frameworks, and the distribution of information and knowledge to stakeholders. The themes are compared to recent developments in the city of Kunming and proposals for future applications are explored

    Enhanced No-Go Theorem for Quantum Position Verification

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    Based on the instantaneous nonlocal quantum computation (INQC), Buhrman et al. proposed an excellent attack strategy to quantum position verification (QPV) protocols in 2011, and showed that, if the colluding adversaries are allowed to previously share unlimited entangled states, it is impossible to design an unconditionally secure QPV protocol in the previous model. Here, trying to overcome this no-go theorem, we find some assumptions in the INQC attack, which are implicit but essential for the success of this attack, and present three different QPV protocols where these assumptions are not satisfied. We show that for the general adversaries, who execute the attack operations at every common time slot or the time when they detect the arrival of the challenge signals from the verifiers, secure QPV is achievable. This implies practically secure QPV can be obtained even if the adversaries is allowed to share unlimited entanglement previously. Here by "practically" we mean that in a successful attack the adversaries need launch a new round of attack on the coming qubits with extremely high frequency so that none of the possible qubits, which may be sent at random time, will be missed. On the other side, using such Superdense INQC (SINQC) attack, the adversaries can still attack the proposed protocols successfully in theory. The particular attack strategies to our protocols are presented respectively. On this basis, we demonstrate the impossibility of secure QPV with looser assumptions, i.e. the enhanced no-go theorem for QPV.Comment: 19 pages, single column, 3 tables, 6 figure
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