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基于逻辑校准的多分类残差网络的肺分割算法 被引量:1
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作者 雷雨婷 张东 杨双 《半导体光电》 CAS 北大核心 2021年第4期585-589,595,共6页
针对图像噪声以及血管、支气管等因素引起的肺分割困难的问题,提出了一种基于逻辑校准的多分类残差网络分割算法。该算法将图像区域划分为肺、背景及边界三类,通过扩大不同类型间的差异来提升分割准确率。算法先将图像分割为固定尺寸区... 针对图像噪声以及血管、支气管等因素引起的肺分割困难的问题,提出了一种基于逻辑校准的多分类残差网络分割算法。该算法将图像区域划分为肺、背景及边界三类,通过扩大不同类型间的差异来提升分割准确率。算法先将图像分割为固定尺寸区域,然后利用残差网络提取纹理特征进行分类训练与测试,实现粗分割。最后对边界区域阈值处理实现细分割。利用公开数据集对该算法进行了测试,实验结果表明,此分割算法在召回率、精确率以及交并比等方面均优于当下前沿的分割网络之一的U-Net,分别达到99.79%,98.13%和97.83%,可为后续的肺部疾病临床诊断提供参考依据。 展开更多
关键词 图像分割 肺分割 多分类残差神经网络 样本不均衡 逻辑校准 阈值分割
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多分类CNN的胶质母细胞瘤多模态MR图像分割 被引量:9
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作者 赖小波 许茂盛 徐小媚 《电子学报》 EI CAS CSCD 北大核心 2019年第8期1738-1747,共10页
为提高胶质母细胞瘤(GBM)多模态磁共振(MR)图像中各肿瘤子区域分割的准确性,提出一种多分类卷积神经网络(CNN)的GBM多模态MR图像自动分割算法.首先在98%缩尾处理和配准GBM多模态MR图像后,利用N4ITK法校正偏移场;其次构建一个主要由4个... 为提高胶质母细胞瘤(GBM)多模态磁共振(MR)图像中各肿瘤子区域分割的准确性,提出一种多分类卷积神经网络(CNN)的GBM多模态MR图像自动分割算法.首先在98%缩尾处理和配准GBM多模态MR图像后,利用N4ITK法校正偏移场;其次构建一个主要由4个卷积层、2个池化层和2个全连接层组成的多分类CNN模型,训练后预分割GBM多模态MR图像,将体素分为5类不同的标签;最后移除所有小于200体素的假阳性区域,中值滤波后获得最终分割结果.以Dice相似性系数DSC、阳性预测值PPV和平均Hausdorff距离AHD为评价指标,利用所提出的算法对F-C-GBM数据集中整个肿瘤组织进行分割,获得的DSC、PPV、AHD分别为0.889±0.087、0.859±0.127和1.923.结果表明,该算法能有效提高GBM多模态MR图像分割的性能,可望有临床应用前景. 展开更多
关键词 胶质母细胞瘤 多模态磁共振图像 自动分割 多分类卷积神经网络 图像块
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一种基于支持向量机的齿轮箱故障诊断方法 被引量:17
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作者 吴德会 《振动.测试与诊断》 EI CSCD 2008年第4期338-342,共5页
提出了一种基于多分类支持向量机(简称MSVM)的齿轮箱故障诊断方法。先根据齿轮箱故障机理和振动特点,探讨了齿轮箱故障诊断试验方案。再测取齿轮箱振动信号,并提取了能反映齿轮箱运转信息的时频域特征参数。通过结合投票法和决策树的基... 提出了一种基于多分类支持向量机(简称MSVM)的齿轮箱故障诊断方法。先根据齿轮箱故障机理和振动特点,探讨了齿轮箱故障诊断试验方案。再测取齿轮箱振动信号,并提取了能反映齿轮箱运转信息的时频域特征参数。通过结合投票法和决策树的基本思想,有针对性地构造了多分类支持向量机决策结构并将其应用于齿轮箱故障诊断。实际齿轮箱故障诊断试验结果表明,该决策结构较好地解决了小样本学习问题,避免了人工神经网络进行诊断时出现的过学习、收敛速度慢、泛化能力弱等缺点,能有效应用于齿轮箱故障诊断。 展开更多
关键词 故障 诊断 决策 齿轮箱 多分类支持向量机人工神经网络
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缺陷汽车玻璃检测方法
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作者 陈晨 董帅 +1 位作者 梁椅辉 邹昆 《智能计算机与应用》 2021年第5期198-201,共4页
汽车玻璃生产过程中会造成断裂、划痕、漏点等表面缺陷,本文结合机器视觉与深度学习提出了自动识别缺陷玻璃的方法。首先,利用玻璃前景、背景人工合成缺陷样本解决负样本不足的问题;将玻璃缺陷细分为多个类别,同时对样本进行分类;将玻... 汽车玻璃生产过程中会造成断裂、划痕、漏点等表面缺陷,本文结合机器视觉与深度学习提出了自动识别缺陷玻璃的方法。首先,利用玻璃前景、背景人工合成缺陷样本解决负样本不足的问题;将玻璃缺陷细分为多个类别,同时对样本进行分类;将玻璃图片进行频域处理过滤背景噪音,再将其与玻璃灰度化后图片进行合成作为分类网络的输入;构造以Alexnet网络为模板的多分类网络进行训练和预测。经过实验验证,该方法准确有效,为玻璃缺陷检测提供了一种可靠的检测方法。 展开更多
关键词 玻璃缺陷检测 深度学习 多分类网络
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Online Internet Traffic Identification Algorithm Based on Multistage Classifier 被引量:3
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作者 杜敏 陈兴蜀 谭骏 《China Communications》 SCIE CSCD 2013年第2期89-97,共9页
Internet traffic classification plays an important role in network management. Many approaches have been proposed to clas-sify different categories of Internet traffic. However, these approaches have specific us-age c... Internet traffic classification plays an important role in network management. Many approaches have been proposed to clas-sify different categories of Internet traffic. However, these approaches have specific us-age contexts that restrict their ability when they are applied in the current network envi-ronment. For example, the port based ap-proach cannot identify network applications with dynamic ports; the deep packet inspec-tion approach is invalid for encrypted network applications; and the statistical based approach is time-onsuming. In this paper, a novel tech-nique is proposed to classify different catego-ries of network applications. The port based, deep packet inspection based and statistical based approaches are integrated as a multi-stage classifier. The experimental results demonstrate that this approach has high rec-ognition rate which is up to 98% and good performance of real-time for traffic identifica-tion. 展开更多
关键词 traffic identification multistageclassifier SELECTION statistical characteristic featuresupport vector machine
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Fuzzy ARTMAP neural network for seafloor classification from multibeam sonar data 被引量:2
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作者 周兴华 Chen Yongqi +1 位作者 Nick Emerson Du Dewen 《High Technology Letters》 EI CAS 2006年第2期219-224,共6页
This paper presents a seafloor classification method of multibeam sonar data, based on the use of Adaptive Resonance Theory (ART) neural networks. A general ART-based neural network, Fuzzy ARTMAP, has been proposed ... This paper presents a seafloor classification method of multibeam sonar data, based on the use of Adaptive Resonance Theory (ART) neural networks. A general ART-based neural network, Fuzzy ARTMAP, has been proposed for seafloor classification of multibeam sonar data. An evolutionary strategy was used to generate new training samples near the cluster boundaries of the neural network, therefore the weights can be revised and refined by supervised learning. The proposed method resolves the training problem for Fuzzy ARTMAP neural networks, which are applied to seafloor classification of multibeam sonar data when there are less than adequate ground-troth samples. The results were synthetically analyzed in comparison with the standard Fuzzy ARTMAP network and a conventional Bayesian classifier. The conclusion can be drawn that Fuzzy ARTMAP neural networks combining with GA algorithms can be alternative powerful tools for seafloor classification of multibeam sonar data. 展开更多
关键词 Fuzzy ARTMAP neural network genetic algorithms seafloor classification multibeam sonar
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防御性蒸馏网络抗梯度攻击的鲁棒性分析
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作者 李哲民 王红霞 许志钦 《系统科学与数学》 CSCD 北大核心 2022年第8期1929-1945,共17页
防御性蒸馏自提出后,由于其对梯度攻击有很好的防御效果,已被广泛用于提高神经网络的鲁棒性.但是原始蒸馏过程需要对教师和学生网络进行共两次训练,即需要双倍的算力.目前许多工作仍然基于原始的防御性蒸馏方法来增强模型的鲁棒性.文章... 防御性蒸馏自提出后,由于其对梯度攻击有很好的防御效果,已被广泛用于提高神经网络的鲁棒性.但是原始蒸馏过程需要对教师和学生网络进行共两次训练,即需要双倍的算力.目前许多工作仍然基于原始的防御性蒸馏方法来增强模型的鲁棒性.文章指出,防御性蒸馏应对梯度攻击的鲁棒性仅与最大的两个logits的差值有关,而logits值与温度和损失函数值有关.学生网络向教师网络学习这一蒸馏过程并非防御性蒸馏起作用的根本原因,只需在训练时增大最大两个logits值之差即可达到防御对抗攻击的作用.文章理论推导并实验验证了上述结论,并基于logits值与温度的正相关关系设计了最佳温度的估计算法,该算法可显著减少寻找最佳温度所消耗的算力.在数据集MNIST和CIFAR-10上,文章提出的快速防御性蒸馏对梯度攻击的鲁棒性与原始防御性蒸馏相同,算法时间消耗和测试集成功率均优于原始防御性蒸馏.文章研究对于防御性蒸馏原理的理解具有理论意义,对防御性蒸馏在实际部署中算力的节省具有实际意义. 展开更多
关键词 对抗样本 梯度攻击 防御性蒸馏 多分类网络 网络鲁棒性
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Multiclass classification based on a deep convolutional network for head pose estimation 被引量:3
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作者 Ying CAI Meng-long YANG Jun LI 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2015年第11期930-939,共10页
Head pose estimation has been considered an important and challenging task in computer vision. In this paper we propose a novel method to estimate head pose based on a deep convolutional neural network (DCNN) for 2D... Head pose estimation has been considered an important and challenging task in computer vision. In this paper we propose a novel method to estimate head pose based on a deep convolutional neural network (DCNN) for 2D face images. We design an effective and simple method to roughly crop the face from the input image, maintaining the individual-relative facial features ratio. The method can be used in various poses. Then two convolutional neural networks are set up to train the head pose classifier and then compared with each other. The simpler one has six layers. It performs well on seven yaw poses but is somewhat unsatisfactory when mixed in two pitch poses. The other has eight layers and more pixels in input layers. It has better performance on more poses and more training samples. Before training the network, two reasonable strategies including shift and zoom are executed to prepare training samples. Finally, feature extraction filters are optimized together with the weight of the classification component through training, to minimize the classification error. Our method has been evaluated on the CAS-PEAL-R1, CMU PIE, and CUBIC FacePix databases. It has better performance than state-of-the-art methods for head pose estimation. 展开更多
关键词 Head pose estimation Deep convolutional neural network Multiclass classification
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A Credit Risk Evaluation Approach to Neural Network Training by Means of Financial Ratios
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作者 Qian Ye 《Journal of Systems Science and Information》 2009年第1期23-32,共10页
In recent years artificial neural networks are used to recognize the risk category of investigated companies. The research is based on data from 81 listed enterprises that applied for credit in domestic regional banks... In recent years artificial neural networks are used to recognize the risk category of investigated companies. The research is based on data from 81 listed enterprises that applied for credit in domestic regional banks operating in China. The backpropagation algorithm-the multilayer feedforward network structure is described. Each firm is described by 9 diagnostic variables and potential borrowers are classified into four classes. The efficiency of classification is evaluated in terms of classification errors calculated from the actual classification made by the credit officers. The results of the experiments show that LevenbergMarque training error is smallest among 4 learning algorithms and its performance is better, and application of artificial neural networks and classification functions can support the creditworthiness evaluation of borrowers. 展开更多
关键词 credit risk evaluation financial ratio neural network classification algorithms the multilayer network
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