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Transformer architecture based on mutual attention for image-anomaly detection
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作者 Mengting ZHANG xiuxia tian 《Virtual Reality & Intelligent Hardware》 2023年第1期57-67,共11页
Image-anomaly detection, which is widely used in industrial fields. Previous studies that attempted to address this problem often trained convolutional neural network-based models(e.g., autoencoders and generative adv... Image-anomaly detection, which is widely used in industrial fields. Previous studies that attempted to address this problem often trained convolutional neural network-based models(e.g., autoencoders and generative adversarial networks) to reconstruct covered parts of input images and calculate the difference between the input and reconstructed images. However, convolutional operations are effective at extracting local features, making it difficult to identify larger image anomalies. Method To this end, we propose a transformer architecture based on mutual attention for image-anomaly separation. This architecture can capture long-term dependencies and fuse local and global features to facilitate better image-anomaly detection. Result Our method was extensively evaluated on several benchmarks, and experimental results showed that it improved the detection capability by 3.1% and localization capability by 1.0% compared with state-of-the-art reconstruction-based methods. 展开更多
关键词 Anomaly detection Swin transformer Feature fusion Attentional mechanism Unsupervised learning
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青藏高原东部暴雨的中尺度有效位能收支分析
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作者 Kuo Zhou Lingkun Ran +1 位作者 Yi Liu xiuxia tian 《Atmospheric and Oceanic Science Letters》 CSCD 2021年第2期53-59,共7页
针对2018年7月10-11日青藏高原东部一次暴雨过程,利用模式模拟资料分析了有效位能分布特征,成因及其对降水发展演变的影响.结果表明,有效位能主要分布在对流层低层4km以下和高层8-14km,高层有效位能和降水有更好的对应性西北冷平流和降... 针对2018年7月10-11日青藏高原东部一次暴雨过程,利用模式模拟资料分析了有效位能分布特征,成因及其对降水发展演变的影响.结果表明,有效位能主要分布在对流层低层4km以下和高层8-14km,高层有效位能和降水有更好的对应性西北冷平流和降水粒子下落的蒸发作用是低层有效位能高值中心的主要成因,而降水过程释放潜热带来的热力扰动叠加高原大地形造成的位温扰动是导致高层有效位能高值的主要原因.有效位能收支分析表明,有效位能的通量输送项以及与动能间的转换项是主要源汇项.低层有效位能的经向通量输送和动能向有效位能的转化补给了有效位能的耗散;高层有效位能向垂直动能转化增强垂直运动是促进降水发展演变的主要因素.高层有效位能与垂直运动之间的正反馈过程使得两者相关性较强;低层较长时间内均存在垂直动能向有效位能的转化,削弱了垂直运动,而西北冷平流使得低层有效位能有增强的趋势,因此二者相关性较弱. 展开更多
关键词 暴雨 有效位能 有效位能收支 垂直运动
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Image copy-move forgery passive detection based on improved PCNN and self-selected sub-images
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作者 Guoshuai Zhou xiuxia tian Aoying Zhou 《Frontiers of Computer Science》 SCIE EI CSCD 2022年第4期131-146,共16页
Image forgery detection remains a challenging problem.For the most common copy-move forgery detection,the robustness and accuracy of existing methods can still be further improved.To the best of our knowledge,we are t... Image forgery detection remains a challenging problem.For the most common copy-move forgery detection,the robustness and accuracy of existing methods can still be further improved.To the best of our knowledge,we are the first to propose an image copy-move forgery passive detection method by combining the improved pulse coupled neural network(PCNN)and the self-selected sub-images.Our method has the following steps:First,contour detection is performed on the input color image,and bounding boxes are drawn to frame the contours to form suspected forgery sub-images.Second,by improving PCNN to perform feature extraction of sub-images,the feature invariance of rotation,scaling,noise adding,and so on can be achieved.Finally,the dual feature matching is used to match the features and locate the forgery regions.What’s more,the self-selected sub-images can quickly obtain suspected forgery sub-images and lessen the workload of feature extraction,and the improved PCNN can extract image features with high robustness.Through experiments on the standard image forgery datasets CoMoFoD and CASIA,it is effectively verified that the robustness score and accuracy of proposed method are much higher than the current best method,which is a more efficient image copy-move forgery passive detection method. 展开更多
关键词 image copy-move forgery passive detection self-selected sub-images pulse coupled neural network(PCNN) dual feature matching
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A privacy-enhancing scheme against contextual knowledge-based attacks in location-based services
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作者 Jiaxun HUA Yu LIU +3 位作者 Yibin SHEN xiuxia tian Yifeng LUO Cheqing JIN 《Frontiers of Computer Science》 SCIE EI CSCD 2020年第3期225-227,共3页
1 Introduction and main contributions Location-based services are springing up around us,while leakages of users'privacy are inevitable during services.Even worse,adversaries may analyze intercepted service data,a... 1 Introduction and main contributions Location-based services are springing up around us,while leakages of users'privacy are inevitable during services.Even worse,adversaries may analyze intercepted service data,and extract more privacy like health and property.Therefore,privacy preservation is an indispensable guarantee on LBS security.Among the previous approaches to privacy preservation,k-anonymity-based ones have drawn much research attention[1-3].However,some privacy concern will be aroused if these schemes are adopted directly.For instance,Ut issues a query"Find the nearest hotel around me"in such an area as Fig.1(privacy profile k=4).DLS algorithm[2]constructs anonymity set A because these four cells have similar probabilities of being queried in the past.However,experienced adversaries can exclude some cells if they have learned rich contextual knowledge(side information)from historical data,such as features of each cell and LBS users. 展开更多
关键词 LBS services knowledge
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