5,291 research outputs found

    A Robust Low-Complexity MIMO Detector for Rank 4 LTE/LTE-A Systems

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    This paper deals with MIMO detection for rank 4 LTE systems. The paper revolves around a previously known detector [1, by Inkyu Lee, TCOM'2010] which we shall refer to as RCSMLD (Reduced-Constellation-Size-Maximum-Likelihood-Detector). However, a direct application of the scheme in [1, by Inkyu Lee, TCOM'2010] to LTE/LTE-A rank 4 test cases results in unsatisfactory performance. The first contribution of the paper is to introduce several modifications that can jointly be applied to the basic RCSMLD scheme which, taken together, result in excellent performance. Our second contribution is the development of a highly efficient hardware structure for RCSMLD that allows for an implementation with very few multiplications.Comment: Accepted for publication in PIMRC-2014, Washington DC, US

    From an axiological standpoint

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    I maintain that intrinsic value is the fundamental concept of axiology. Many contemporary philosophers disagree; they say the proper object of value theory is final value. I examine three accounts of the nature of final value: the first claims that final value is non‐instrumental value; the second claims that final value is the value a thing has as an end; the third claims that final value is ultimate or non‐derivative value. In each case, I argue that the concept of final value described is either identical with the classical notion of intrinsic value or is not a plausible candidate for the primary concept of axiology

    Maxwell-Chern-Simons theory for curved spacetime backgrounds

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    We consider a modified version of four-dimensional electrodynamics, which has a photonic Chern-Simons-like term with spacelike background vector in the action. Light propagation in curved spacetime backgrounds is discussed using the geometrical-optics approximation. The corresponding light path is modified, which allows for new effects. In a Schwarzschild background, for example, there now exist stable bounded orbits of light rays and the two polarization modes of light rays in unbounded orbits can have different gravitational redshifts. An Erratum with important corrections has been published, which appears as Appendix E in this arXiv version.Comment: 28 pages with elsart, v6: published version of paper and Erratu

    Combinatorial Properties of Triangle-Free Rectangle Arrangements and the Squarability Problem

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    We consider arrangements of axis-aligned rectangles in the plane. A geometric arrangement specifies the coordinates of all rectangles, while a combinatorial arrangement specifies only the respective intersection type in which each pair of rectangles intersects. First, we investigate combinatorial contact arrangements, i.e., arrangements of interior-disjoint rectangles, with a triangle-free intersection graph. We show that such rectangle arrangements are in bijection with the 4-orientations of an underlying planar multigraph and prove that there is a corresponding geometric rectangle contact arrangement. Moreover, we prove that every triangle-free planar graph is the contact graph of such an arrangement. Secondly, we introduce the question whether a given rectangle arrangement has a combinatorially equivalent square arrangement. In addition to some necessary conditions and counterexamples, we show that rectangle arrangements pierced by a horizontal line are squarable under certain sufficient conditions.Comment: 15 pages, 13 figures, extended version of a paper to appear at the International Symposium on Graph Drawing and Network Visualization (GD) 201

    Generalization of Linearized Gouy-Chapman-Stern Model of Electric Double Layer for Nanostructured and Porous Electrodes: Deterministic and Stochastic Morphology

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    We generalize linearized Gouy-Chapman-Stern theory of electric double layer for nanostructured and morphologically disordered electrodes. Equation for capacitance is obtained using linear Gouy-Chapman (GC) or Debye-u¨\rm{\ddot{u}}ckel equation for potential near complex electrode/electrolyte interface. The effect of surface morphology of an electrode on electric double layer (EDL) is obtained using "multiple scattering formalism" in surface curvature. The result for capacitance is expressed in terms of the ratio of Gouy screening length and the local principal radii of curvature of surface. We also include a contribution of compact layer, which is significant in overall prediction of capacitance. Our general results are analyzed in details for two special morphologies of electrodes, i.e. "nanoporous membrane" and "forest of nanopillars". Variations of local shapes and global size variations due to residual randomness in morphology are accounted as curvature fluctuations over a reference shape element. Particularly, the theory shows that the presence of geometrical fluctuations in porous systems causes enhanced dependence of capacitance on mean pore sizes and suppresses the magnitude of capacitance. Theory emphasizes a strong influence of overall morphology and its disorder on capacitance. Finally, our predictions are in reasonable agreement with recent experimental measurements on supercapacitive mesoporous systems

    Orientation-Constrained Rectangular Layouts

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    We construct partitions of rectangles into smaller rectangles from an input consisting of a planar dual graph of the layout together with restrictions on the orientations of edges and junctions of the layout. Such an orientation-constrained layout, if it exists, may be constructed in polynomial time, and all orientation-constrained layouts may be listed in polynomial time per layout.Comment: To appear at Algorithms and Data Structures Symposium, Banff, Canada, August 2009. 12 pages, 5 figure

    Higher Diet Quality Does Not Predict Lower Medicare Costs but Does Predict Number of Claims in Mid-Aged Australian Women

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    Optimal dietary quality, indicated by higher diet quality index scores, reflects greater adherence to National dietary recommendations and is also associated with lower morbidity and mortality from chronic disease. Whether this is reflected in lower health care cost over time has rarely been examined. The aim of this study was to examine whether higher diet quality, as measured by the Australian Recommended Food Score (ARFS), was associated with lower health care costs within the mid-aged cohort of the Australian Longitudinal Study on Women’s Health. We found that there was a statistically significant association between five year cumulative costs and ARFS, but in the opposite direction to that predicted, with those in the highest quintiles of ARFS having higher health care costs. However the number of Medicare claims over the six year period (2002–2007) was lower for those in the highest compared with the lowest quintile, p = 0.002. There is a need to monitor both costs and claims over time to examine health care usage in the longer term in order to determine whether savings are eventually obtained for those with the dietary patterns that adhere more closely to National recommendations
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