258 research outputs found

    Smartphone based public participant emergency rescue information platform for earthquake zone – “E-Explorer”

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    Devastating earthquake can often cause the disaster area communication interrupt, traffic paralysis, etc. It is difficult for the emergency rescue force to get the disaster area in time. Therefore, active local participation in the quake-hit areas to aid each other appeals extremely important. The paper is based on a self-developed smartphone software called “E-Explorer”, study its significance and its working methods to help the public participate in the earthquake rescue actively when external network are cut off. “E-Explorer” can help deliver important information for personal survival, let rescue workers locate the positions of survivors trapped, creating an efficient self-help and mutual rescue platform for the earthquake-stricken people

    Microstructure Evolution and Surface Cracking Behavior of Superheavy Forgings during Hot Forging

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    In recent years, superheavy forgings that are manufactured from 600 t grade ingots have been applied in the latest generation of nuclear power plants to provide good safety. However, component production is pushing the limits of the current free-forging industry. Large initial grain sizes and a low strain rate are the main factors that contribute to the deformation of superheavy forgings during forging. In this study, 18Mn18Cr0.6N steel with a coarse grain structure was selected as a model material. Hot compression and hot tension tests were conducted at a strain rate of 10−4·s−1. The essential nucleation mechanism of the dynamic recrystallization involved low-angle grain boundary formation and subgrain rotation, which was independent of the original high-angle grain boundary bulging and the presence of twins. Twins were formed during the growth of dynamic recrystallization grains. The grain refinement was not obvious at 1150°C. A lowering of the deformation temperature to 1050°C resulted in a fine grain structure; however, the stress increased significantly. Crack-propagation paths included high-angle grain boundaries, twin boundaries, and the insides of grains, in that order. For superheavy forging, the ingot should have a larger height and a smaller diameter

    Classification via semi-Riemannian spaces

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    In this paper, we develop a geometric framework for linear or nonlinear discriminant subspace learning and classification. In our framework, the structures of classes are conceptualized as a semi-Riemannian manifold which is considered as a submanifold embedded in an ambient semi-Riemannian space. The class structures of original samples can be characterized and deformed by local metrics of the semi-Riemannian space. Semi-Riemannian metrics are uniquely determined by the smoothing of discrete functions and the nullity of the semi-Riemannian space. Based on the geometrization of class structures, optimizing class structures in the feature space is equivalent to maximizing the quadratic quantities of metric tensors in the semi-Riemannian space. Thus supervised discriminant subspace learning reduces to unsupervised semi-Riemannian manifold learning. Based on the proposed framework, a novel algorithm, dubbed as Semi-Riemannian Discriminant Analysis (SRDA), is presented for subspace-based classification. The performance of SRDA is tested on face recognition (singular case) and handwritten capital letter classification (nonsingular case) against existing algorithms. The experimental results show that SRDA works well on recognition and classification, implying that semi-Riemannian geometry is a promising new tool for pattern recognition and machine learning. 1

    Product Fuzzy Recommendation of Online Reviews Based on Consumer Psychological Motives

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    Sentiment analysis of online comments and their application has become a hot topic. Meanwhile the evaluation and emotion method has challenged researchers and practitioners. This paper proposes a fuzzy modeling for the evaluation and emotion of online review texts by means of the theory of consumption motivation type and establishes corresponding fuzzy corpus. A calculation method of comprehensive evaluation and emotion with respect to the consumer‟s preference for product attributes provide reasoning antecedents. Establishment of fuzzy inference rules give results of recommendation to consumers of four different motivations. Experimental results prove the validity of the proposed method
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