1,545 research outputs found

    Partial-Matching and Hausdorff RMS Distance Under Translation: Combinatorics and Algorithms

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    We consider the RMS distance (sum of squared distances between pairs of points) under translation between two point sets in the plane, in two different setups. In the partial-matching setup, each point in the smaller set is matched to a distinct point in the bigger set. Although the problem is not known to be polynomial, we establish several structural properties of the underlying subdivision of the plane and derive improved bounds on its complexity. These results lead to the best known algorithm for finding a translation for which the partial-matching RMS distance between the point sets is minimized. In addition, we show how to compute a local minimum of the partial-matching RMS distance under translation, in polynomial time. In the Hausdorff setup, each point is paired to its nearest neighbor in the other set. We develop algorithms for finding a local minimum of the Hausdorff RMS distance in nearly linear time on the line, and in nearly quadratic time in the plane. These improve substantially the worst-case behavior of the popular ICP heuristics for solving this problem.Comment: 31 pages, 6 figure

    Cutting simulation with consideration of the material hardening in the Shear Zone of AISI1045

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    By the use of high energy synchrotron X-ray diffraction it was possible to determine the stress state in the chip formation zone during orthogonal cutting of AISI1045. The analysis of the diffractograms showed a hardening of the material during the movement through the shear zone. For this reason nano indentation experiments on prepared chips have been carried out. With these experiments, the material hardening has been confirmed. The nano indentation experiments were reproduced by FEM simulations and it was possible to determine flow curves of the hardened material above the shear zone based on existing flow curves of AISI1045. Thus, cutting simulations have been carried out, which considered the material hardening in the shear zone. The simulation results were then compared with the results of the in-situ strain measurements

    Determinants of Prenatal Care and Supplement Use: The Case of Honduras

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    Context: Literature suggests that prenatal care and prenatal supplement use improves pregnancy outcomes. However, we do not know the factors associated with prenatal care and supplement use in Honduras.Objective: To identify characteristics of Honduran women who are the least and most likely to use prenatal care and supplements.Methods: Data from a 2001 Honduras cross-sectional survey of women was used to assess their use of prenatal care and supplements. All data was weighted, resulting in a sample size of n = 5647 women who had a live birth since January 1996. Bivariate and multivariate analyses were used to examine factors associated with prenatal care and supplement use.Results: Current education level was highly positively related to prenatal care and supplement use. Women who were 35 years or older at the time of their most recent birth, currently unmarried, of non-Catholic religious affiliation, and of low SES were significantly less likely to have used prenatal care and supplements. Women who reported the intentionality of their most recent birth as unwanted also were significantly less likely to have used prenatal care and supplements. Prenatal care was the most significant determinant of prenatal supplement use.Conclusion: There are significant differences between Honduran women who use prenatal care and supplements and women who do not. Efforts to increase prenatal health services among underserved women, especially women who are older, unmarried, with no formal education, of low SES, of a non-Catholic religious affiliation, and at risk for an unwanted pregnancy, may significantly improve pregnancy outcomes in Honduras

    Film calibration for the Skylab/ATM S-056 X-ray telescope

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    The sensitometry and film calibration effort for the Skylab/ATM S-056 X-ray telescope is summarized. The apparatus and procedures used are described together with the two types of flight film used, Kodak SO-212 and SO-242. The sensitometry and processing of the flight film are discussed, and the results are presented in the form of the characteristic curves and related data. The use of copy films is also discussed

    A Transiting Jupiter Analog

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    Decadal-long radial velocity surveys have recently started to discover analogs to the most influential planet of our solar system, Jupiter. Detecting and characterizing these worlds is expected to shape our understanding of our uniqueness in the cosmos. Despite the great successes of recent transit surveys, Jupiter analogs represent a terra incognita, owing to the strong intrinsic bias of this method against long orbital periods. We here report on the first validated transiting Jupiter analog, Kepler-167e (KOI-490.02), discovered using Kepler archival photometry orbiting the K4-dwarf KIC-3239945. With a radius of (0.91±0.02)(0.91\pm0.02) RJupR_{\mathrm{Jup}}, a low orbital eccentricity (0.060.04+0.100.06_{-0.04}^{+0.10}) and an equilibrium temperature of (131±3)(131\pm3) K, Kepler-167e bears many of the basic hallmarks of Jupiter. Kepler-167e is accompanied by three Super-Earths on compact orbits, which we also validate, leaving a large cavity of transiting worlds around the habitable-zone. With two transits and continuous photometric coverage, we are able to uniquely and precisely measure the orbital period of this post snow-line planet (1071.2323±0.00061071.2323\pm0.0006 d), paving the way for follow-up of this K=11.8K=11.8 mag target.Comment: 14 pages, 10 figures. Accepted to ApJ. Posteriors available at https://github.com/CoolWorlds/Kepler-167-Posterior

    A phenomenological model for the X-ray spectrum of Nova V2491 Cygni

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    The X-ray flux of Nova V2491 Cyg reached a maximum some forty days after optical maximum. The X-ray spectrum at that time, obtained with the RGS of XMM-Newton, shows deep, blue-shifted absorption by ions of a wide range of ionization. We show that the deep absorption lines of the X-ray spectrum at maximum, and nine days later, are well described by the following phenomenological model with emission from a central blackbody and from a collisionally ionized plasma (CIE). The blackbody spectrum (BB) is absorbed by three main highly-ionized expanding shells; the CIE and BB are absorbed by cold circumstellar and interstellar matter that includes dust. The outflow density does not decrease monotonically with distance. The abundances of the shells indicate that they were ejected from an O-Ne white dwarf. We show that the variations on time scales of hours in the X-ray spectrum are caused by a combination of variation in the central source and in the column density of the ionized shells. Our phenomenological model gives the best description so far of the supersoft X-ray spectrum of nova V2491 Cyg, but underpredicts, by a large factor, the optical and ultraviolet flux. The X-ray part of the spectrum must originate from a very different layer in the expanding envelope, presumably much closer to the white dwarf than the layers responsible for the optical/ultraviolet spectrum. This is confirmed by absence of any correlation between the X-ray and UV/optical observed fluxes.Comment: 11 pages, 6 figure

    The Elder Economic Security Initiative™ Program: The Elder Economic Security Standard™ Index for Wisconsin

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    This report addresses income adequacy for Wisconsin’s older adults using the WOW-GI Elder Economic Security Standard Index (the Index) methodology. The Index benchmarks basic costs of living for elder households and illustrates how costs of living vary geographically and are based on the characteristics of elder households, including household size, home ownership or renter status, and health status. The costs are based on market costs for basic needs of elder households and do not assume any public or private supports

    Partial-Matching RMS Distance Under Translation: Combinatorics and Algorithms

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    We consider the problem of minimizing the RMS distance (sum of squared distances between pairs of points) under translation between two point sets A and B, in the plane, with (Formula presented.), in the partial-matching setup, in which each point in B is matched to a distinct point in A. Although the problem is not known to be polynomial, we establish several structural properties of the underlying subdivision (Formula presented.) of the plane and derive improved bounds on its complexity. Specifically, we show that this complexity is (Formula presented.), so it is only quadratic in |A|. These results lead to the best known algorithm for finding a translation for which the partial-matching RMS distance between the point sets is minimized. In addition, we show how to compute a local minimum of the partial-matching RMS distance under translation, in polynomial time. © 2017 Springer Science+Business Media New Yor
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