3,757 research outputs found

    The Estimation of Minimum Efficient Scale of the Port Industry

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    publisher: Elsevier articletitle: The estimation of minimum efficient scale of the port industry journaltitle: Transport Policy articlelink: http://dx.doi.org/10.1016/j.tranpol.2016.04.012 content_type: article copyright: © 2016 Elsevier Ltd. All rights reserved

    Attitude Control System Design & Verification for CNUSAIL-1 with Solar/Drag Sail

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    CNUSAIL-1, to be launched into low-earth orbit, is a cubesat-class satellite equipped with a 2 m × 2 m solar sail. One of CNUSAIL’s missions is to deploy its solar sail system, thereby deorbiting the satellite, at the end of the satellite’s life. This paper presents the design results of the attitude control system for CNUSAIL-1, which maintains the normal vector of the sail by a 3-axis active attitude stabilization approach. The normal vector can be aligned in two orientations: i) along the anti-nadir direction, which minimizes the aerodynamic drag during the nadir-pointing mode, or ii) along the satellite velocity vector, which maximizes the drag during the deorbiting mode. The attitude control system also includes a B-dot controller for detumbling and an eigen-axis maneuver algorithm. The actuators for the attitude control are magnetic torquers and reaction wheels. The feasibility and performance of the design are verified in high-fidelity nonlinear simulations

    Criterion for transformation of transverse domain wall to vortex or antivortex wall in soft magnetic thin-film nanostripes

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    We report on the criterion for the dynamic transformation of the internal structure of moving domain walls (DWs) in soft magnetic thin-film nanostripes above the Walker threshold field, Hw. In order for the process of transformation from transverse wall (TW) to vortex wall (VW) or antivortex wall (AVW) occurs, the edge-soliton core of the TW-type DW should grow sufficiently to the full width at half maximum of the out-of-plane magnetizations of the core area of the stabilized vortex (or antivortex) by moving inward along the transverse (width) direction. Upon completion of the nucleation of the vortex (antivortex) core, the VW (AVW) is stabilized, and then its core accompanies the gyrotropic motion in a potential well (hill) of a given nanostripe. Field strengths exceeding the Hw, which is the onset field of DW velocity breakdown, are not sufficient but necessary conditions for dynamic DW transformation

    Learning Optimal Deep Projection of 18^{18}F-FDG PET Imaging for Early Differential Diagnosis of Parkinsonian Syndromes

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    Several diseases of parkinsonian syndromes present similar symptoms at early stage and no objective widely used diagnostic methods have been approved until now. Positron emission tomography (PET) with 18^{18}F-FDG was shown to be able to assess early neuronal dysfunction of synucleinopathies and tauopathies. Tensor factorization (TF) based approaches have been applied to identify characteristic metabolic patterns for differential diagnosis. However, these conventional dimension-reduction strategies assume linear or multi-linear relationships inside data, and are therefore insufficient to distinguish nonlinear metabolic differences between various parkinsonian syndromes. In this paper, we propose a Deep Projection Neural Network (DPNN) to identify characteristic metabolic pattern for early differential diagnosis of parkinsonian syndromes. We draw our inspiration from the existing TF methods. The network consists of a (i) compression part: which uses a deep network to learn optimal 2D projections of 3D scans, and a (ii) classification part: which maps the 2D projections to labels. The compression part can be pre-trained using surplus unlabelled datasets. Also, as the classification part operates on these 2D projections, it can be trained end-to-end effectively with limited labelled data, in contrast to 3D approaches. We show that DPNN is more effective in comparison to existing state-of-the-art and plausible baselines.Comment: 8 pages, 3 figures, conference, MICCAI DLMIA, 201

    Tag location method integrating GNSS and RFID technology

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    Mesoscopic Fano Effect in a Quantum Dot Embedded in an Aharonov-Bohm Ring

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    The Fano effect, which occurs through the quantum-mechanical cooperation between resonance and interference, can be observed in electron transport through a hybrid system of a quantum dot and an Aharonov-Bohm ring. While a clear correlation appears between the height of the Coulomb peak and the real asymmetric parameter qq for the corresponding Fano lineshape, we need to introduce a complex qq to describe the variation of the lineshape by the magnetic and electrostatic fields. The present analysis demonstrates that the Fano effect with complex asymmetric parameters provides a good probe to detect a quantum-mechanical phase of traversing electrons.Comment: REVTEX, 9 pages including 8 figure

    Large capacitance-voltage hysteresis loops in SiO[sub 2] films containing Ge nanocrystals produced by ion implantation and annealing

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    Metal-oxide-semiconductorstructures containing Genanocrystals (NCs) of 3–4nm diameter and 2×10¹²cm⁻² density are shown to exhibit capacitance-voltage hysteresis of 20.9V, one of the largest observed in Ge-NC based nonvolatile memories. The Ge NCs were fabricated in an oxide of 30nm thickness by ion implantation with 30keV Ge₂⁻ ions to an equivalent fluence of 1×10¹⁶Gecm⁻² followed by annealing at 950 °C for 10min. Secondary ion mass spectroscopy and transmission electron microscopy demonstrate the existence of Ge NCs whose average distance from the SiO₂∕Siinterface is about 6.7nm. It is shown that the memory effect is a likely consequence of charge trapping at Ge NCs and that it is enhanced by accurately controlling the distribution of Ge NCs with respect to the Si∕SiO₂interface.This work was partially supported by the QuantumFunctional Semiconductor Research Center in Dongguk University and by the National Program for Tera Level Nano Devices through MOST. S.-H.C. acknowledges partial support from the National Research Program for the 0.1 Terabit Non-Volatile Memory Development sponsored by Korea Ministry of Science & Technology. R.G.E. additionally acknowledges the Australian Research Council for their partial financial support of this work
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