111,733 research outputs found

    Promoting sustainable construction: European and British networks at the knowledge-policy interface

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    The responsibility of builders, developers, planners, architects and policy-makers to promote more sustainable urban environments and buildings is consistently prioritized in nascent European, national and local planning strategies. Yet what counts as ‘sustainable construction’ varies by issue, sector and policy mandate. Proponents of sustainable construction might promote technological shifts in terms of materials, energy use and waste reduction, or they might encourage cultural and behavioural adaptations to how society views, uses and plans its built environment. This paper examines this problematic bifurcation of sustainable construction into two exclusive agendas: the construction technology agenda and the urban sustainability planning agenda, each constituted by distinct policy and sector-based networks. It is argued that the orientation to detail in the construction technology agenda operates at odds with the holistic process orientation of the broader urban sustainability agenda, thus complicating the effective translation or co-generation of sustainable construction knowledge between the two networks. The lack of integration between these two sets of networks should be cause for concern, yet appears to be largely overlooked in mainstream policy processes

    Large space antenna technology applied to radar-imaging, rain-rate measurements, and ocean wind sensing

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    During the last decade, the utility of spaceborne microwave remote sensing systems for ocean windspeed measurement, ocean wave imaging and sea ice studies was demonstrated. Development of large space antennas offers some interesting possibilities for rain rate measurements, ocean and ice studies, and radar imaging. The joint use of active and passive sensors using the 15 m antenna for ocean, ice, and soil moisture studies; rain rate measurements; and radar imaging is considered. Verification of the frequency agile rain radar concept with Shuttle offers the possibility of much needed rain rate statistics over the ocean

    Cached Sufficient Statistics for Efficient Machine Learning with Large Datasets

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    This paper introduces new algorithms and data structures for quick counting for machine learning datasets. We focus on the counting task of constructing contingency tables, but our approach is also applicable to counting the number of records in a dataset that match conjunctive queries. Subject to certain assumptions, the costs of these operations can be shown to be independent of the number of records in the dataset and loglinear in the number of non-zero entries in the contingency table. We provide a very sparse data structure, the ADtree, to minimize memory use. We provide analytical worst-case bounds for this structure for several models of data distribution. We empirically demonstrate that tractably-sized data structures can be produced for large real-world datasets by (a) using a sparse tree structure that never allocates memory for counts of zero, (b) never allocating memory for counts that can be deduced from other counts, and (c) not bothering to expand the tree fully near its leaves. We show how the ADtree can be used to accelerate Bayes net structure finding algorithms, rule learning algorithms, and feature selection algorithms, and we provide a number of empirical results comparing ADtree methods against traditional direct counting approaches. We also discuss the possible uses of ADtrees in other machine learning methods, and discuss the merits of ADtrees in comparison with alternative representations such as kd-trees, R-trees and Frequent Sets.Comment: See http://www.jair.org/ for any accompanying file

    Japan and the Global Environment

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    Thermodynamic evaluation of transonic compressor rotors using the finite volume approach

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    Research at NASA Lewis Research Center gave the opportunity to incorporate new control volumes in the Denton 3-D finite-volume time marching code. For duct flows, the new control volumes require no transverse smoothing and this allows calculations with large transverse gradients in properties without significant numerical total pressure losses. Possibilities for improving the Denton code to obtain better distributions of properties through shocks were demonstrated. Much better total pressure distributions through shocks are obtained when the interpolated effective pressure, needed to stabilize the solution procedure, is used to calculate the total pressure. This simple change largely eliminates the undershoot in total pressure down-stream of a shock. Overshoots and undershoots in total pressure can then be further reduced by a factor of 10 by adopting the effective density method, rather than the effective pressure method. Use of a Mach number dependent interpolation scheme for pressure then removes the overshoot in static pressure downstream of a shock. The stability of interpolation schemes used for the calculation of effective density is analyzed and a Mach number dependent scheme is developed, combining the advantages of the correct perfect gas equation for subsonic flow with the stability of 2-point and 3-point interpolation schemes for supersonic flow

    D-particle bound states and generalized instantons

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    We compute the principal contribution to the index in the supersymmetric quantum mechanical systems which are obtained by reduction to 0+1 dimensions of N=1\mathcal{N}=1, D=4,6,10D=4,6,10 super-Yang-Mills theories with gauge group SU(N). The results are: 1N2{1\over{N^{2}}} for D=4,6D=4,6, ∑d∣N1d2\sum_{d | N} {1\over{d^{2}}} for D=10. We also discuss the D=3 case.Comment: harvmac, 24 pages; v2. references added, typos corrected; v3. one more reference adde

    Remote sensor imagery in urban research - Some potentialities and problem

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    Imaging techniques of urban data collection for development and plannin
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