1,130 research outputs found

    Marking parts to aid robot vision

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    The premarking of parts for subsequent identification by a robot vision system appears to be beneficial as an aid in the automation of certain tasks such as construction in space. A simple, color coded marking system is presented which allows a computer vision system to locate an object, calculate its orientation, and determine its identity. Such a system has the potential to operate accurately, and because the computer shape analysis problem has been simplified, it has the ability to operate in real time

    Level Set Approach to Reversible Epitaxial Growth

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    We generalize the level set approach to model epitaxial growth to include thermal detachment of atoms from island edges. This means that islands do not always grow and island dissociation can occur. We make no assumptions about a critical nucleus. Excellent quantitative agreement is obtained with kinetic Monte Carlo simulations for island densities and island size distributions in the submonolayer regime.Comment: 7 pages, 9 figure

    Precision Measurement of the Radiative B\Beta Decay of the Free Neutron

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    The standard model predicts that, in addition to a proton, an electron, and an antineutrino, a continuous spectrum of photons is emitted in the β\beta decay of the free neutron. We report on the RDK II experiment which measured the photon spectrum using two different detector arrays. An annular array of bismuth germanium oxide scintillators detected photons from 14 to 782~keV. The spectral shape was consistent with theory, and we determined a branching ratio of 0.00335 ±\pm 0.00005 [stat] ±\pm 0.00015 [syst]. A second detector array of large area avalanche photodiodes directly detected photons from 0.4 to 14~keV. For this array, the spectral shape was consistent with theory, and the branching ratio was determined to be 0.00582 ±\pm 0.00023 [stat] ±\pm 0.00062 [syst]. We report the first precision test of the shape of the photon energy spectrum from neutron radiative decay and a substantially improved determination of the branching ratio over a broad range of photon energies

    The International Sport Coaching Bachelor Degree Standards of the International Council for Coaching Excellence

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    Sport coaching is at a pivotal moment in its short history. The publication of the International Sport Coaching Framework by the International Council for Coaching Excellence (ICCE) in 2013 has drawn attention to coaching world-wide and fostered a step change in the way coaching systems are understood and built. Within this evolving context, higher education institutions are increasingly playing a greater role in the education and development of coaches in many countries. One way in which they are doing so is through the delivery of partial or full sport coaching degrees. ICCE recognises this emerging landscape. In this article we present an introduction to the newly developed International Sport Coaching Bachelor Degree Standards. The Standards are the culmination of a 12-month process of cooperation and consultation between an expert group and the coaching community at large. They aim to respond to the needs of higher education institutions and serve as an internationally accepted reference point to aid the development of bachelor coaching degrees that prepare coaches to effectively support athletes and participants

    Economic evaluation of day hospital versus intensive outpatient mentalization-based treatment alongside a randomized controlled trial with 36-month follow-up

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    Mentalization-based treatment (MBT) has demonstrated robust effectiveness in the treatment of borderline personality disorder (BPD) in both day hospital (MBT-DH) and intensive outpatient MBT (MBT-IOP) programs. Given the large differences in intensity and associated treatment costs, there is a need for studies comparing their cost-effectiveness. A health economic evaluation of MBT-DH versus MBT-IOP was performed alongside a multicenter randomized controlled trial with a 36-month follow-up. In three mental health-care institutions in the Netherlands, 114 patients were randomly allocated to MBT-DH (n = 70) or MBT-IOP (n = 44) and assessed every 6 months. Societal costs were compared with quality-adjusted life years (QALYs) gained and the number of months in remission over 36 months. The QALY gains over 36 months were 1.96 (SD = 0.58) for MBT-DH and 1.83 (SD = 0.56) for MBT-IOP; the respective number of months in remission were 16.0 (SD = 11.5) and 11.1 (SD = 10.7). Societal costs were €106,038 for MBT-DH and €91,368 for MBT-IOP. The incremental cost for one additional QALY with MBT-DH compared with MBT-IOP was €107,000. The incremental cost for 1 month in remission was almost €3000. Assuming a willingness-to-pay threshold of €50,000 for a QALY, there was a 33% likelihood that MBT-DH is more cost-effective than MBT-IOP in terms of costs per QALY. Although MBT-DH leads to slightly more QALYs and remission months, it is probably not cost-effective when compared with MBT-IOP for BPD patients, as the small additional health benefits in MBT-DH did not outweigh the substantially higher societal costs

    Spiral surface growth without desorption

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    Spiral surface growth is well understood in the limit where the step motion is controlled by the local supersaturation of adatoms near the spiral ridge. In epitaxial thin-film growth, however, spirals can form in a step-flow regime where desorption of adatoms is negligible and the ridge dynamics is governed by the non-local diffusion field of adatoms on the whole surface. We investigate this limit numerically using a phase-field formulation of the Burton-Cabrera-Frank model, as well as analytically. Quantitative predictions, which differ strikingly from those of the local limit, are made for the selected step spacing as a function of the deposition flux, as well as for the dependence of the relaxation time to steady-state growth on the screw dislocation density.Comment: 9 pages, 3 figures, RevTe

    A contiuum model for low temperature relaxation of crystal steps

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    High and low temperature relaxation of crystal steps are described in a unified picture, using a continuum model based on a modified expression of the step free energy. Results are in agreement with experiments and Monte Carlo simulations of step fluctuations and monolayer cluster diffusion and relaxation. In an extended model where mass exchange with neighboring terraces is allowed, step transparency and a low temperature regime for unstable step meandering are found.Comment: Submitted to Phys.Rev.Let

    Robust modeling of human contact networks across different scales and proximity-sensing techniques

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    The problem of mapping human close-range proximity networks has been tackled using a variety of technical approaches. Wearable electronic devices, in particular, have proven to be particularly successful in a variety of settings relevant for research in social science, complex networks and infectious diseases dynamics. Each device and technology used for proximity sensing (e.g., RFIDs, Bluetooth, low-power radio or infrared communication, etc.) comes with specific biases on the close-range relations it records. Hence it is important to assess which statistical features of the empirical proximity networks are robust across different measurement techniques, and which modeling frameworks generalize well across empirical data. Here we compare time-resolved proximity networks recorded in different experimental settings and show that some important statistical features are robust across all settings considered. The observed universality calls for a simplified modeling approach. We show that one such simple model is indeed able to reproduce the main statistical distributions characterizing the empirical temporal networks
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