3,610 research outputs found

    Port safety evaluation from a captain's perspective: The Korean experience

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    There are many factors affecting navigational safety in ports, including weather, the characteristics of the channels and vessel types, etc. This paper aims to identify the factors influencing navigational safety in ports and to analyze the extent to which such factors affect the safety of ports from the perspective of ship captains through a real case study. A quantitative analysis is carried out using the data collected from 21 captains who have over 10. years experience in operating ships individually. The identified factors indicate risk implications in ports. A fuzzy analytical hierarchy process is used to evaluate the importance of the factors and to rank the safety levels of the targeted ports in Korea from a captain's perspective. Consequently, among Busan, Ulsan, Gwangyang, Incheon, and Mokpo, Busan is evaluated by captains as the safest port, while Mokpo is the most risky. The research also reveals that it is applicable to use domain expert knowledge when historical failure data is unavailable or difficult to access to evaluate port safety. The result shows great research significance in terms of providing relevant stakeholders, such as port authorities and shipping companies, with an insight into port safety performance and thus facilitating the development of the associated risk control measures. © 2014 Elsevier Ltd

    The effect of dynamical scattering on single-plane phase retrieval in electron ptychography

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    Segmented and pixelated detectors on scanning transmission electron microscopes enable the complex specimen transmission function to be reconstructed. Imaging the transmission function is key to interpreting the electric and magnetic properties of the specimen, and as such four-dimensional scanning transmission electron microscopy (4D-STEM) imaging techniques are crucial for our understanding of functional materials. Many of the algorithms used in the reconstruction of the transmission function rely on the multiplicative approximation and the (weak) phase object approximation, which are not valid for many materials, particularly at high resolution. Herein, we study the breakdown of simple phase imaging in thicker samples. We demonstrate the behavior of integrated center of mass imaging, single-side band ptychography, and Wigner distribution deconvolution over a thickness series of simulated GaN 4D-STEM datasets. We further give guidance as to the optimal focal conditions for obtaining a more interpretable dataset using these algorithms

    Deformation of the Fermi surface in the extended Hubbard model

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    The deformation of the Fermi surface induced by Coulomb interactions is investigated in the t-t'-Hubbard model. The interplay of the local U and extended V interactions is analyzed. It is found that exchange interactions V enhance small anisotropies producing deformations of the Fermi surface which break the point group symmetry of the square lattice at the Van Hove filling. This Pomeranchuck instability competes with ferromagnetism and is suppressed at a critical value of U(V). The interaction V renormalizes the t' parameter to smaller values what favours nesting. It also induces changes on the topology of the Fermi surface which can go from hole to electron-like what may explain recent ARPES experiments.Comment: 5 pages, 4 ps figure

    O(αsv2)O(\alpha_s v^2) correction to pseudoscalar quarkonium decay to two photons

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    We investigate the O(αsv2)O(\alpha_s v^2) correction to the process of pseudoscalar quarkonium decay to two photons in nonrelativistic QCD (NRQCD) factorization framework. The short-distance coefficient associated with the relative-order v2v^2 NRQCD matrix element is determined to next-to-leading order in αs\alpha_s through the perturbative matching procedure. Some technical subtleties encountered in calculating the {O(\alpha_s) QCD amplitude are thoroughly addressed.Comment: v2, 28 pages, 2 figures and 2 tables, matching the published version; typos corrected, references added, as well as a "Note added in the proof

    Analytical study on holographic superconductors in external magnetic field

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    We investigate the holographic superconductors immersed in an external magnetic field by using the analytical approach. We obtain the spatially dependent condensate solutions in the presence of the magnetism and find analytically that the upper critical magnetic field satisfies the relation given in the Ginzburg-Landau theory. We observe analytically the reminiscent of the Meissner effect where the magnetic field expels the condensate. Extending to the D-dimensional Gauss-Bonnet AdS black holes, we examine the influence given by the Gauss-Bonnet coupling on the condensation. Different from the positive coupling, we find that the negative Gauss-Bonnet coupling enhances the condensation when the external magnetism is not strong enough.Comment: revised version, to appear in JHE

    MIA-Prognosis: A Deep Learning Framework to Predict Therapy Response

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    Predicting clinical outcome is remarkably important but challenging. Research efforts have been paid on seeking significant biomarkers associated with the therapy response or/and patient survival. However, these biomarkers are generally costly and invasive, and possibly dissatifactory for novel therapy. On the other hand, multi-modal, heterogeneous, unaligned temporal data is continuously generated in clinical practice. This paper aims at a unified deep learning approach to predict patient prognosis and therapy response, with easily accessible data, e.g., radiographics, laboratory and clinical information. Prior arts focus on modeling single data modality, or ignore the temporal changes. Importantly, the clinical time series is asynchronous in practice, i.e., recorded with irregular intervals. In this study, we formalize the prognosis modeling as a multi-modal asynchronous time series classification task, and propose a MIA-Prognosis framework with Measurement, Intervention and Assessment (MIA) information to predict therapy response, where a Simple Temporal Attention (SimTA) module is developed to process the asynchronous time series. Experiments on synthetic dataset validate the superiory of SimTA over standard RNN-based approaches. Furthermore, we experiment the proposed method on an in-house, retrospective dataset of real-world non-small cell lung cancer patients under anti-PD-1 immunotherapy. The proposed method achieves promising performance on predicting the immunotherapy response. Notably, our predictive model could further stratify low-risk and high-risk patients in terms of long-term survival.Comment: MICCAI 2020 (Early Accepted; Student Travel Award

    5D gravity and the discrepant G measurements

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    It is shown that 5D Kaluza-Klein theory stabilized by an external bulk scalar field may solve the discrepant laboratory G measurements. This is achieved by an effective coupling between gravitation and the geomagnetic field. Experimental considerations are also addressed.Comment: 13 pages, to be published in: Proceedings of the 18th Course of the School on Cosmology and Gravitation: The gravitational Constant. Generalized gravitational theories and experiments (30 April-10 May 2003, Erice). Ed. by G. T. Gillies, V. N. Melnikov and V. de Sabbata, (Kluwer), 13pp. (in print) (2003

    The NLO QCD Corrections to BcB_c Meson Production in Z0Z^0 Decays

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    The decay width of Z0Z^0 to BcB_c meson is evaluated at the next-to-leading order(NLO) accuracy in strong interaction. Numerical calculation shows that the NLO correction to this process is remarkable. The quantum chromodynamics(QCD)renormalization scale dependence of the results is obviously depressed, and hence the uncertainties lying in the leading order calculation are reduced.Comment: 14 pages, 7 figures; references added; expressions and typos ammende
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