33,800 research outputs found

    Sustainability best practice in PPP: Case study of a hospital project in the UK

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    Globally, sustainable development has been given high priority for the Government agenda in order to achieve a balance of social, economic and environmental factors. The UK government realise the importance and criticality of sustainable development and they intend to use the public procurement power to demand more sustainable public building development to improve energy efficiency and reduce carbon emissions. Public Private Partnership (PPP) is an effective procurement tool for the government to deliver the provision of public services. In the UK, the most common PPP form is Private Finance Initiative (PFI). Up until March 2012, a total of 717 PFI projects have been delivered to sustain social and economic development in the UK (HM Treasury, 2012). There is potential to use PPP to incorporate the sustainability agenda and support low carbon economic development. However, little research has been conducted to demonstrate the benefits and advantages of the PPP procurement system incorporating sustainable development. This paper aims to demonstrate best practice in sustainable development through PPP (PFI) procurement system in the UK. It initially illustrates the relationship between PPP and sustainable development and then uses a case study of one of the largest PPP hospital projects in the UK, utilising interviews and secondary data to show evidence of how the sustainability issues have been addressed within the procurement process and the advantage and limitations of using the PPP procurement system in delivering sustainable development. The results show best practice across different strands of sustainability through contribution to local employment and the local economy, a high percentage of waste recycling, dust and noise reduction and technical innovations such as green roofs, natural ventilation and a focus on occupant comfort

    Vortex-like surface wave and its role in the transient phenomena of meta-material focusing

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    We show that a slab of meta-material (with ϵ=μ=1+iΔ\epsilon=\mu=-1+i\Delta) possesses a vortex-like surface wave with no ability to transport energy, whose nature is completely different from a localized mode or a standing wave. Through computations based on a rigorous time-dependent Green's function approach, we demonstrate that such a mode inevitably generates characteristic image oscillations in two dimensional focusing with even a monochromatic source, which were observed in many numerical simulations, but such oscillations are weak in three dimensional focusing.Comment: To appear in the March 7th issue of Appl. Phys. Let

    Convergence of Online Mirror Descent

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    In this paper we consider online mirror descent (OMD) algorithms, a class of scalable online learning algorithms exploiting data geometric structures through mirror maps. Necessary and sufficient conditions are presented in terms of the step size sequence {ηt}t\{\eta_t\}_{t} for the convergence of an OMD algorithm with respect to the expected Bregman distance induced by the mirror map. The condition is limtηt=0,t=1ηt=\lim_{t\to\infty}\eta_t=0, \sum_{t=1}^{\infty}\eta_t=\infty in the case of positive variances. It is reduced to t=1ηt=\sum_{t=1}^{\infty}\eta_t=\infty in the case of zero variances for which the linear convergence may be achieved by taking a constant step size sequence. A sufficient condition on the almost sure convergence is also given. We establish tight error bounds under mild conditions on the mirror map, the loss function, and the regularizer. Our results are achieved by some novel analysis on the one-step progress of the OMD algorithm using smoothness and strong convexity of the mirror map and the loss function.Comment: Published in Applied and Computational Harmonic Analysis, 202