为解决缫丝时绪下茧粒与工作背景辨识度较低、茧粒分布密集以及茧粒之间相互遮挡而漏检的问题,课题组提出了一种基于改进YOLOv5s的缫丝机绪下茧粒数检测算法。该算法在Backbone中引入RFB-SE(receptive field block-squeeze and excitati...为解决缫丝时绪下茧粒与工作背景辨识度较低、茧粒分布密集以及茧粒之间相互遮挡而漏检的问题,课题组提出了一种基于改进YOLOv5s的缫丝机绪下茧粒数检测算法。该算法在Backbone中引入RFB-SE(receptive field block-squeeze and excitation)模块,实现了对与工作背景辨识度较低茧粒的检测;使用空间增强注意力模块(spatially enhanced attention module,SEAM)来改进网络的颈部(Neck),解决了由于茧粒遮挡而造成漏检的问题;引入Soft-NMS代替非极大值抑制(non-max suppression,NMS),改变了原始模型对于预测框的处理方式,更好地改善了漏检问题。实验结果表明:该算法在数据集上召回率达到了98.3%;平均精度均值达到了98.8%,相比原始模型提高了3.3%。该算法解决了茧粒与工作背景辨识度低、茧粒间相互遮挡而造成的漏检问题。展开更多
The driving effects of climate change and human activities on vegetation change have always been a focal point of research.However,the coupling mechanisms of these driving factors across different temporal and spatial...The driving effects of climate change and human activities on vegetation change have always been a focal point of research.However,the coupling mechanisms of these driving factors across different temporal and spatial scales remain controversial.The Southwestern Alpine Canyon Region of China(SACR),as an ecologically fragile area,is highly sensitive to the impacts of climate change and human activities.This study constructed a vegetation cover dataset for the SACR based on the Enhanced Vegetation Index(EVI)from 2000 to 2020.Spatial autocorrelation,Theil-Sen trend,and Mann-Kendall tests were used to analyze the spatiotemporal characteristics of vegetation cover changes.The main drivers of spatial heterogeneity in vegetation cover were identified using the optimal parameter geographic detector,and an improved residual analysis model was employed to quantify the relative contributions of climate change and human activities to interannual vegetation cover changes.The main findings are as follows:Spatially,vegetation cover exceeds 60%in most areas,especially in the southern part of the study area.However,the border area between Linzhi and Changdu exhibits lower vegetation cover.Climate factors are the primary drivers of spatial heterogeneity in vegetation cover,with temperature having the most significant influence,as indicated by its q-value,which far exceeds that of other factors.Additionally,the interaction q-value between the two factors significantly increases,showing a relationship of bivariate enhancement and nonlinear enhancement.In terms of temporal changes,vegetation cover shows an overall improving trend from 2000 to 2020,with significant increases observed in 68.93%of the study area.Among these,human activities are the main factors driving vegetation cover change,with a relative contribution rate of 41.31%,while climate change and residual factors contribute 35.66%and 23.53%,respectively.By thoroughly exploring the coupled mechanisms of vegetation change,this study provides important references for the sustainable management and conservation of the vegetation ecosystem in the SACR.展开更多
Due to the rapid evolution of Advanced Persistent Threats(APTs)attacks,the emergence of new and rare attack samples,and even those never seen before,make it challenging for traditional rule-based detection methods to ...Due to the rapid evolution of Advanced Persistent Threats(APTs)attacks,the emergence of new and rare attack samples,and even those never seen before,make it challenging for traditional rule-based detection methods to extract universal rules for effective detection.With the progress in techniques such as transfer learning and meta-learning,few-shot network attack detection has progressed.However,challenges in few-shot network attack detection arise from the inability of time sequence flow features to adapt to the fixed length input requirement of deep learning,difficulties in capturing rich information from original flow in the case of insufficient samples,and the challenge of high-level abstract representation.To address these challenges,a few-shot network attack detection based on NFHP(Network Flow Holographic Picture)-RN(ResNet)is proposed.Specifically,leveraging inherent properties of images such as translation invariance,rotation invariance,scale invariance,and illumination invariance,network attack traffic features and contextual relationships are intuitively represented in NFHP.In addition,an improved RN network model is employed for high-level abstract feature extraction,ensuring that the extracted high-level abstract features maintain the detailed characteristics of the original traffic behavior,regardless of changes in background traffic.Finally,a meta-learning model based on the self-attention mechanism is constructed,achieving the detection of novel APT few-shot network attacks through the empirical generalization of high-level abstract feature representations of known-class network attack behaviors.Experimental results demonstrate that the proposed method can learn high-level abstract features of network attacks across different traffic detail granularities.Comparedwith state-of-the-artmethods,it achieves favorable accuracy,precision,recall,and F1 scores for the identification of unknown-class network attacks through cross-validation onmultiple datasets.展开更多
目的雷达点云语义分割是3维环境感知的重要环节,准确分割雷达点云对象对无人驾驶汽车和自主移动机器人等应用具有重要意义。由于雷达点云数据具有非结构化特征,为提取有效的语义信息,通常将不规则的点云数据投影成结构化的2维图像,但会...目的雷达点云语义分割是3维环境感知的重要环节,准确分割雷达点云对象对无人驾驶汽车和自主移动机器人等应用具有重要意义。由于雷达点云数据具有非结构化特征,为提取有效的语义信息,通常将不规则的点云数据投影成结构化的2维图像,但会造成点云数据中几何信息丢失,不能得到高精度分割效果。此外,真实数据集中存在数据分布不均匀问题,导致小样本物体分割效果较差。为解决这些问题,本文提出一种基于稀疏注意力和实例增强的雷达点云分割方法,有效提高了激光雷达点云语义分割精度。方法针对数据集中数据分布不平衡问题,采用实例注入方式增强点云数据。首先,通过提取数据集中的点云实例数据,并在训练中将实例数据注入到每一帧点云中,实现实例增强的效果。由于稀疏卷积网络不能获得较大的感受野,提出Transformer模块扩大网络的感受野。为了提取特征图的关键信息,使用基于稀疏卷积的空间注意力机制,显著提高了网络性能。另外,对不同类别点云对象的边缘,提出新的TVloss用于增强网络的监督能力。结果本文提出的模型在SemanticKITTI和nuScenes数据集上进行测试。在SemanticKITTI数据集上,本文方法在线单帧精度在平均交并比(mean intersection over union,mIoU)指标上为64.6%,在nuScenes数据集上为75.6%。消融实验表明,本文方法的精度在baseline的基础上提高了3.1%。结论实验结果表明,本文提出的基于稀疏注意力和实例增强的雷达点云分割方法在SemanticKITTI和nuScenes数据集上都取得了较好表现,提高了网络对点云细节的分割能力,使点云分割结果更加准确。展开更多
文摘由于低照度图像具有对比度低、细节丢失严重、噪声大等缺点,现有的目标检测算法对低照度图像的检测效果不理想.为此,本文提出一种结合空间感知注意力机制和多尺度特征融合(Spatial-aware Attention Mechanism and Multi-Scale Feature Fusion,SAM-MSFF)的低照度目标检测方法 .该方法首先通过多尺度交互内存金字塔融合多尺度特征,增强低照度图像特征中的有效信息,并设置内存向量存储样本的特征,捕获样本之间的潜在关联性;然后,引入空间感知注意力机制获取特征在空间域的长距离上下文信息和局部信息,从而增强低照度图像中的目标特征,抑制背景信息和噪声的干扰;最后,利用多感受野增强模块扩张特征的感受野,对具有不同感受野的特征进行分组重加权计算,使检测网络根据输入的多尺度信息自适应地调整感受野的大小.在ExDark数据集上进行实验,本文方法的平均精度(mean Average Precision,mAP)达到77.04%,比现有的主流目标检测方法提高2.6%~14.34%.
文摘为解决缫丝时绪下茧粒与工作背景辨识度较低、茧粒分布密集以及茧粒之间相互遮挡而漏检的问题,课题组提出了一种基于改进YOLOv5s的缫丝机绪下茧粒数检测算法。该算法在Backbone中引入RFB-SE(receptive field block-squeeze and excitation)模块,实现了对与工作背景辨识度较低茧粒的检测;使用空间增强注意力模块(spatially enhanced attention module,SEAM)来改进网络的颈部(Neck),解决了由于茧粒遮挡而造成漏检的问题;引入Soft-NMS代替非极大值抑制(non-max suppression,NMS),改变了原始模型对于预测框的处理方式,更好地改善了漏检问题。实验结果表明:该算法在数据集上召回率达到了98.3%;平均精度均值达到了98.8%,相比原始模型提高了3.3%。该算法解决了茧粒与工作背景辨识度低、茧粒间相互遮挡而造成的漏检问题。
基金funded by the National Key Research and Development Program of China(Grant No.2022YFF1302903).
文摘The driving effects of climate change and human activities on vegetation change have always been a focal point of research.However,the coupling mechanisms of these driving factors across different temporal and spatial scales remain controversial.The Southwestern Alpine Canyon Region of China(SACR),as an ecologically fragile area,is highly sensitive to the impacts of climate change and human activities.This study constructed a vegetation cover dataset for the SACR based on the Enhanced Vegetation Index(EVI)from 2000 to 2020.Spatial autocorrelation,Theil-Sen trend,and Mann-Kendall tests were used to analyze the spatiotemporal characteristics of vegetation cover changes.The main drivers of spatial heterogeneity in vegetation cover were identified using the optimal parameter geographic detector,and an improved residual analysis model was employed to quantify the relative contributions of climate change and human activities to interannual vegetation cover changes.The main findings are as follows:Spatially,vegetation cover exceeds 60%in most areas,especially in the southern part of the study area.However,the border area between Linzhi and Changdu exhibits lower vegetation cover.Climate factors are the primary drivers of spatial heterogeneity in vegetation cover,with temperature having the most significant influence,as indicated by its q-value,which far exceeds that of other factors.Additionally,the interaction q-value between the two factors significantly increases,showing a relationship of bivariate enhancement and nonlinear enhancement.In terms of temporal changes,vegetation cover shows an overall improving trend from 2000 to 2020,with significant increases observed in 68.93%of the study area.Among these,human activities are the main factors driving vegetation cover change,with a relative contribution rate of 41.31%,while climate change and residual factors contribute 35.66%and 23.53%,respectively.By thoroughly exploring the coupled mechanisms of vegetation change,this study provides important references for the sustainable management and conservation of the vegetation ecosystem in the SACR.
基金supported by the National Natural Science Foundation of China(Nos.U19A208162202320)+2 种基金the Fundamental Research Funds for the Central Universities(No.SCU2023D008)the Science and Engineering Connotation Development Project of Sichuan University(No.2020SCUNG129)the Key Laboratory of Data Protection and Intelligent Management(Sichuan University),Ministry of Education.
文摘Due to the rapid evolution of Advanced Persistent Threats(APTs)attacks,the emergence of new and rare attack samples,and even those never seen before,make it challenging for traditional rule-based detection methods to extract universal rules for effective detection.With the progress in techniques such as transfer learning and meta-learning,few-shot network attack detection has progressed.However,challenges in few-shot network attack detection arise from the inability of time sequence flow features to adapt to the fixed length input requirement of deep learning,difficulties in capturing rich information from original flow in the case of insufficient samples,and the challenge of high-level abstract representation.To address these challenges,a few-shot network attack detection based on NFHP(Network Flow Holographic Picture)-RN(ResNet)is proposed.Specifically,leveraging inherent properties of images such as translation invariance,rotation invariance,scale invariance,and illumination invariance,network attack traffic features and contextual relationships are intuitively represented in NFHP.In addition,an improved RN network model is employed for high-level abstract feature extraction,ensuring that the extracted high-level abstract features maintain the detailed characteristics of the original traffic behavior,regardless of changes in background traffic.Finally,a meta-learning model based on the self-attention mechanism is constructed,achieving the detection of novel APT few-shot network attacks through the empirical generalization of high-level abstract feature representations of known-class network attack behaviors.Experimental results demonstrate that the proposed method can learn high-level abstract features of network attacks across different traffic detail granularities.Comparedwith state-of-the-artmethods,it achieves favorable accuracy,precision,recall,and F1 scores for the identification of unknown-class network attacks through cross-validation onmultiple datasets.
文摘目的雷达点云语义分割是3维环境感知的重要环节,准确分割雷达点云对象对无人驾驶汽车和自主移动机器人等应用具有重要意义。由于雷达点云数据具有非结构化特征,为提取有效的语义信息,通常将不规则的点云数据投影成结构化的2维图像,但会造成点云数据中几何信息丢失,不能得到高精度分割效果。此外,真实数据集中存在数据分布不均匀问题,导致小样本物体分割效果较差。为解决这些问题,本文提出一种基于稀疏注意力和实例增强的雷达点云分割方法,有效提高了激光雷达点云语义分割精度。方法针对数据集中数据分布不平衡问题,采用实例注入方式增强点云数据。首先,通过提取数据集中的点云实例数据,并在训练中将实例数据注入到每一帧点云中,实现实例增强的效果。由于稀疏卷积网络不能获得较大的感受野,提出Transformer模块扩大网络的感受野。为了提取特征图的关键信息,使用基于稀疏卷积的空间注意力机制,显著提高了网络性能。另外,对不同类别点云对象的边缘,提出新的TVloss用于增强网络的监督能力。结果本文提出的模型在SemanticKITTI和nuScenes数据集上进行测试。在SemanticKITTI数据集上,本文方法在线单帧精度在平均交并比(mean intersection over union,mIoU)指标上为64.6%,在nuScenes数据集上为75.6%。消融实验表明,本文方法的精度在baseline的基础上提高了3.1%。结论实验结果表明,本文提出的基于稀疏注意力和实例增强的雷达点云分割方法在SemanticKITTI和nuScenes数据集上都取得了较好表现,提高了网络对点云细节的分割能力,使点云分割结果更加准确。
