18,601 research outputs found

    Spin-resolved second-order correlation energy of the two-dimensional uniform electron gas

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    For the two-dimensional electron gas, the exact high-density limit of the correlation energy is evaluated here numerically for all values of the spin polarization. The result is spin-resolved into \uparrow\uparrow, \uparrow\downarrow, and \downarrow\downarrow contributions and parametrized analytically. Interaction-strength interpolation yields a simple model (LSD) for the correlation energy at finite densities.Comment: 5 pages, 2 figure

    Efficient Image-Space Extraction and Representation of 3D Surface Topography

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    Surface topography refers to the geometric micro-structure of a surface and defines its tactile characteristics (typically in the sub-millimeter range). High-resolution 3D scanning techniques developed recently enable the 3D reconstruction of surfaces including their surface topography. In his paper, we present an efficient image-space technique for the extraction of surface topography from high-resolution 3D reconstructions. Additionally, we filter noise and enhance topographic attributes to obtain an improved representation for subsequent topography classification. Comprehensive experiments show that the our representation captures well topographic attributes and significantly improves classification performance compared to alternative 2D and 3D representations.Comment: Initial version of the paper accepted at the IEEE ICIP Conference 201

    An efficient length- and rate-preserving concatenation of polar and repetition codes

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    We improve the method in \cite{Seidl:10} for increasing the finite-lengh performance of polar codes by protecting specific, less reliable symbols with simple outer repetition codes. Decoding of the scheme integrates easily in the known successive decoding algorithms for polar codes. Overall rate and block length remain unchanged, the decoding complexity is at most doubled. A comparison to related methods for performance improvement of polar codes is drawn.Comment: to be presented at International Zurich Seminar (IZS) 201

    Strategy Workshops and Strategic Change

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    Despite the attention that strategic change as a topic of research has received, there remain considerable difficulties in conceptualizing the actual sources of strategic change. Strategy workshops represent one obvious and explicit research site since organizations often use such events as a means of effecting or initiating strategic change. This paper examines empirical data from ninety-nine strategy workshops in ten separate organizations to address the research question: Do strategy workshops produce strategic change? The paper concludes that workshops can produce change but that one-off workshops are much less effective than a series of workshops. The data presented indicates that the elapsed duration of the entire series of workshops, the frequency of workshops, the scope and autonomy of the unit concerned, and the seniority of participants have an impact on the success or failure of the venture
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