845 research outputs found

    Signatures of the neutrino mass hierarchy in supernova neutrinos

    Full text link
    The undetermined neutrino mass hierarchy may leave an observable imprint on the neutrino fluxes from a core-collapse supernova (SN). The interpretation of the observables, however, is subject to the uncertain SN models and the flavor conversion mechanism of neutrinos in a SN. We attempt to propose a qualitative interpretation of the expected neutrino events at terrestrial detectors, focusing on the accretion phase of the neutrino burst. The flavor conversions due to neutrino self-interaction, the MSW effect, and the Earth regeneration effect are incorporated in the calculation. It leads to several distinct scenarios that are identified by the neutrino mass hierarchies and the collective flavor transitions. Consequences resulting from the variation of incident angles and SN models are also discussed.Comment: 15 pages, 9 figure

    Comparative Study of Some Population-based Optimization Algorithms on Inverse Scattering of a Two-Dimensional Perfectly Conducting Cylinder in Slab Medium

    Get PDF
    [[abstract]]The application of four techniques for the shape reconstruction of a 2-D metallic cylinder buried in dielectric slab medium by measured the cattered fields outside is studied in the paper. The finite-difference time-domain (FDTD) technique is employed for electromagnetic analyses for both the forward and inverse scattering problems, while the shape reconstruction problem is transformed into optimization one during the course of inverse scattering. Then, four techniques including asynchronous particle swarm optimization (APSO), PSO, dynamic differential evolution (DDE) and self-adaptive DDE (SADDE) are applied to reconstruct the location and shape of the 2-Dmetallic cylinder for comparative purposes. The statistical performances of these algorithms are compared. The results show that SADDE outperforms PSO, APSO and DDE in terms of the ability of exploring the optima. However, these results are considered to be indicative and do not generally apply to all optimization problems in electromagnetics.[[incitationindex]]SCI[[incitationindex]]EI[[booktype]]çŽ™æœŹ[[booktype]]電歐

    DESIGN OF MICRO-GRIPPER WITH TOPOLOGY OPTIMAL COMPLIANT MECHANISMS

    Get PDF
    ABSTRACT The objective of this paper describes a new method to design a micro-gripper. In the paper, we use compliant mechanism actuated by micro combined V-shape electrothermal actuator to design a microgripper that the claw can clip the micro object. The compliant mechanism employs flexible to generate movement without any hinge; therefore, it is suitable for MEMS manufacture. The design of micro-gripper is accomplished in compliant mechanism with topology optimum and solved by sequential linear programming (SLP) methods. The design considerations, the analysis method, and the design results are discussed

    RESEARCH ON THE MARKETING AND PUBLIC RELATIONS EFFECT AND SPORT EVENT SATISFACTION OF THE TAIPEI 2017 UNIVERSIADE

    Get PDF
    The purpose of this study is to investigate the spectators’ marketing and public relations and sport event satisfaction with their participation in the Taipei 2017 Universiade. Meanwhile, based on the comparison of different personal background variables, this study compares the attractiveness and satisfaction of the spectators’ marketing and public relations recognition, marketing and public relations attitude, event planning and sport event services. A random sampling method is adopted in this study. Among spectators, university students of the Taipei 2017 Universiade are selected. A total of 700 questionnaires are distributed and 680 valid questionnaires are collected. The effective recovery rate is 97.14%. The research tool of this study is “Satisfaction scale of marketing and public relations effect and sport event satisfaction of the Taipei 2017 Universiade”. This study uses statistical methods such as descriptive statistics, independent sample t-tests, and so forth. The results of this study are: (1) In the Taipei 2017 Universiade, spectators have the highest attractiveness with “Internet” in “media tools” of marketing and public relations recognition, followed by the factor of “TV”; (2) In “marketing and public relations attitude” of the Taipei 2017 Universiade, “marketing and public relations present efforts and earnest of Taiwan” ranks the highest, followed by “marketing and public relations are impressed”; (3) In “sport event services” of the Taipei 2017 Universiade, “auditorium” ranks the highest, followed by “broadcast notification”; (4) There is no significant difference in the attractiveness and satisfaction among spectators with different personal background for “marketing and public relations recognition”, “marketing and public relations attitude”, and “sport event services” in the Taipei 2017 Universiade.  Article visualizations

    Masking Improves Contrastive Self-Supervised Learning for ConvNets, and Saliency Tells You Where

    Full text link
    While image data starts to enjoy the simple-but-effective self-supervised learning scheme built upon masking and self-reconstruction objective thanks to the introduction of tokenization procedure and vision transformer backbone, convolutional neural networks as another important and widely-adopted architecture for image data, though having contrastive-learning techniques to drive the self-supervised learning, still face the difficulty of leveraging such straightforward and general masking operation to benefit their learning process significantly. In this work, we aim to alleviate the burden of including masking operation into the contrastive-learning framework for convolutional neural networks as an extra augmentation method. In addition to the additive but unwanted edges (between masked and unmasked regions) as well as other adverse effects caused by the masking operations for ConvNets, which have been discussed by prior works, we particularly identify the potential problem where for one view in a contrastive sample-pair the randomly-sampled masking regions could be overly concentrated on important/salient objects thus resulting in misleading contrastiveness to the other view. To this end, we propose to explicitly take the saliency constraint into consideration in which the masked regions are more evenly distributed among the foreground and background for realizing the masking-based augmentation. Moreover, we introduce hard negative samples by masking larger regions of salient patches in an input image. Extensive experiments conducted on various datasets, contrastive learning mechanisms, and downstream tasks well verify the efficacy as well as the superior performance of our proposed method with respect to several state-of-the-art baselines
    • 

    corecore