195 research outputs found

    A simple and natural interpretations of the DAMPE cosmic-ray electron/positron spectrum within two sigma deviations

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    The DArk Matter Particle Explorer (DAMPE) experiment has recently announced the first results for the measurement of total electron plus positron fluxes between 25 GeV and 4.6 TeV. A spectral break at about 0.9 TeV and a tentative peak excess around 1.4 TeV have been found. However, it is very difficult to reproduce both the peak signal and the smooth background including spectral break simultaneously. We point out that the numbers of events in the two energy ranges (bins) close to the 1.4 TeV excess have 1σ1\sigma deficits. With the basic physics principles such as simplicity and naturalness, we consider the −2σ-2\sigma, +2σ+2\sigma, and −1σ-1\sigma deviations due to statistical fluctuations for the 1229.3~GeV bin, 1411.4~GeV bin, and 1620.5~GeV bin. Interestingly, we show that all the DAMPE data can be explained consistently via both the continuous distributed pulsar and dark matter interpretations, which have χ2≃17.2\chi^{2} \simeq 17.2 and χ2≃13.9\chi^{2} \simeq 13.9 (for all the 38 points in DAMPE electron/positron spectrum with 3 of them revised), respectively. These results are different from the previous analyses by neglecting the 1.4 TeV excess. At the same time, we do a similar global fitting on the newly released CALET lepton data, which could also be interpreted by such configurations. Moreover, we present a U(1)DU(1)_D dark matter model with Breit-Wigner mechanism, which can provide the proper dark matter annihilation cross section and escape the CMB constraint. Furthermore, we suggest a few ways to test our proposal.Comment: 18 pages, 6 figures, 5 tables. Figures and Bibs update

    The Application of Two-level Attention Models in Deep Convolutional Neural Network for Fine-grained Image Classification

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    Fine-grained classification is challenging because categories can only be discriminated by subtle and local differences. Variances in the pose, scale or rotation usually make the problem more difficult. Most fine-grained classification systems follow the pipeline of finding foreground object or object parts (where) to extract discriminative features (what). In this paper, we propose to apply visual attention to fine-grained classification task using deep neural network. Our pipeline integrates three types of attention: the bottom-up attention that propose candidate patches, the object-level top-down attention that selects relevant patches to a certain object, and the part-level top-down attention that localizes discriminative parts. We combine these attentions to train domain-specific deep nets, then use it to improve both the what and where aspects. Importantly, we avoid using expensive annotations like bounding box or part information from end-to-end. The weak supervision constraint makes our work easier to generalize. We have verified the effectiveness of the method on the subsets of ILSVRC2012 dataset and CUB200_2011 dataset. Our pipeline delivered significant improvements and achieved the best accuracy under the weakest supervision condition. The performance is competitive against other methods that rely on additional annotations

    Fine-grained Discriminative Localization via Saliency-guided Faster R-CNN

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    Discriminative localization is essential for fine-grained image classification task, which devotes to recognizing hundreds of subcategories in the same basic-level category. Reflecting on discriminative regions of objects, key differences among different subcategories are subtle and local. Existing methods generally adopt a two-stage learning framework: The first stage is to localize the discriminative regions of objects, and the second is to encode the discriminative features for training classifiers. However, these methods generally have two limitations: (1) Separation of the two-stage learning is time-consuming. (2) Dependence on object and parts annotations for discriminative localization learning leads to heavily labor-consuming labeling. It is highly challenging to address these two important limitations simultaneously. Existing methods only focus on one of them. Therefore, this paper proposes the discriminative localization approach via saliency-guided Faster R-CNN to address the above two limitations at the same time, and our main novelties and advantages are: (1) End-to-end network based on Faster R-CNN is designed to simultaneously localize discriminative regions and encode discriminative features, which accelerates classification speed. (2) Saliency-guided localization learning is proposed to localize the discriminative region automatically, avoiding labor-consuming labeling. Both are jointly employed to simultaneously accelerate classification speed and eliminate dependence on object and parts annotations. Comparing with the state-of-the-art methods on the widely-used CUB-200-2011 dataset, our approach achieves both the best classification accuracy and efficiency.Comment: 9 pages, to appear in ACM MM 201

    Element Recognition and Innovation Transformation of Cultural and Creative Products: Based on Eye Movement Experiment

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    This paper analyzes tourists’ perceived preferences for cultural and creative product elements using human-computer interaction technology and constructs the innovation and transformation path of cultural and creative products from four dimensions: concept, elements, content, and structure. The Great Wall tourism cultural and creative products are used as an example. The findings demonstrate that: (1) From a behavioral data viewpoint, cultural and creative items’ overall inventiveness, formal design, manufacturing method, area, cultural collection value, and function have varying degrees of influence on visitors’ perceived preferences; (2) The richness and attraction of character expression, action, and form components from the hotspot map and matrix map can boost the visual engagement impact of visitors. Scenic area architecture may enhance visitors’ immersion experiences of local culture since it serves as the design prototype for cultural and creative businesses. (3) The number of fixation points, total fixation time, and saccade frequency of cultural and creative products with various design elements differ significantly when viewed from the perspective of the eye movement index, and these differences are further presented as individualized tourist behavior characteristics. (4) From a design standpoint, it is essential that the circumstances of the product satisfy the needs of visitors in order to produce high-quality cultural and creative products. Innovative ideas should be used to steer the innovation and transformation of cultural and creative products, enhancing the universal design of products with element innovation, enhancing the cultural legacies of products with content innovation, and lengthening the market cycle of products with structural innovation. The use of modern technology broadens the research methodologies for the tourism field and creates new research environments for tourism experimentation
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