基于多感受野与分组混合注意力机制的肺结节分割研究

从CT图像中自动有效分割肺结节对诊断和治疗肺部肿瘤具有重要意义。鉴于肺结节在肺部所占比例很小、形态不规则、与一些邻近组织和器官在视觉上非常相似,给分割任务带来困难,本文提出一种基于多感受野与分组混合注意力机制的肺结节分割网络MRF-GMA。首先,该网络通过多感受野特征聚合模块,捕获不同尺度的结节;其次,利用分组混合注意力模块,提升对结节像素的分辨能力;最后,采用混合损失函数对训练过程进行优化,缓解了类不平衡的问题。在实验部分,本文分别将MRF-GMA与FCN、SegNet、R2U-Net和Attention U-Net等进行比较,结果表明,MRF-GMA模型在Dice相似性系数(DSC)、召回率(recall)和准确率(accuracy)等方面均表现最优,相比Attention U-Net模型,分别提高了2.25、1.19和2.98个百分点。     

基于改进I-Attention U-Net的锌浮选泡沫图像分割算法

针对泡沫图像的高度复杂性导致其难以被准确分割的难题,本文提出了一种新的I-Attention U-Net网络用于泡沫图像分割.该算法以U-Net网络作为主干网络,使用Inception模块替换第一卷积池化层来提取泡沫图像的多尺度、多层次浅层特征信息;引入金字塔池化模块,通过对不同尺度的特征图求和来提升分割效果;并对自注意力门控单元进行改进,使注意力单元更适合于浮选泡沫图像的分割,强化深层特征的重要性并对不同尺寸的泡沫边界进行强化学习.研究结果表明：本文所提出算法的Jaccard系数为91.73%,Dice系数为95.66%.与同类其他分割算法结果相比,Jaccard系数及Dice系数分别提高了1.59%、0.88%.该模型能够较好地对锌浮选泡沫图像进行分割,解决欠分割与过分割的问题,为后续的泡沫特征提取奠定基础.此外,该方法检测时间和模型参数少,具备可以部署在工业现场计算机的能力,有一定的实际应用价值.     

基于改进U-Net方法的脑肿瘤磁共振图像分割

为提高脑肿瘤磁共振图像分割精度,在U-Net图像分割方法基础上,提出了一种引入注意力机制的深度学习改进模型,利用全局上下文信息,使模型重点关注需要分割区域的特征,并抑制无关的特征,以此提高模型的分割精度,同时引入残差块来加速模型的训练.实验结果表明:提出的改进模型相比U-Net方法,脑肿瘤MRI图像的分割精度有了提高,...     

一种基于U-Net网络心脏MR图像左室识别的图割后处理快速算法

为了从心脏MR图像中分割出左心室,提出了一种基于U-Net网络的图割后处理算法.先训练U-Net网络分割网络得到概率图,接着采用图割算法进行后处理.为了减少图割算法运行时间,采用图像形态学操作去除无需后处理区域,只保留分割结果的边缘区域进行图割优化.采用Dice系数和召回率这两种评价指标,在Sunnybrook数据集上...     

融合注意力空洞卷积和Transformer的矿石图像分割

在金矿研磨过程中,矿石粒度大小对后期黄金冶炼起着至关重要的作用,是一个不可忽略的关键参数。为解决图像分割中多数矿石表面不规则、棱角多,粘连等问题,通过结合注意力与多尺度空洞卷积的Vit Transformer模型研究了矿石图像分割。首先使用ResNet34作为下采样主干,增强对金矿石的特征提取能力;其次采用Transformer模块解决长距离依赖问题,融合复合通道注意力空洞模块提升网络对金矿石边缘特征的提取能力,提高了网络的抗干扰能力并扩大感受野。实验结果表明：本文算法准确率达到95.84%,Dice系数达到94.69%,交并比(IoU)达到90.39%,错误率低至7.83%。与其他算法对比,本文方法精度、Dice系数、IoU更高,可以较好地完成矿石图像分割任务。     

基于残差U-Net网络的染色体图像分割方法

针对染色体识别的难题,提出一种基于残差U-Net网络的染色体图像分割方法.以残差网络和U-Net网络为基础简化深层网络的训练,利用丰富的跳跃连接促进信息传播;通过将U-Net网络底层的卷积层替换成不同尺度的空洞卷积,保持特征空间分辨率不变的同时扩大特征感受野,实现多尺度感受野提取图像特征的同时减少特性信息的丢失;压缩路...     

基于核磁共振图像的脑肿瘤分割方法研究

利用脑肿瘤核磁共振(Magnetic resonance,MR)图像提供的关于肿瘤和脑组织的形状、大小与定位等信息准确地分割出脑肿瘤区域,对监测脑肿瘤患者的肿瘤生长或缩小、制定手术或放化疗计划都起着重要的作用.探讨了脑肿瘤MR图像分割的背景与意义,整理了脑肿瘤分割方法中常用的评估指标以及实验数据库的发展过程.基于脑肿瘤...     

基于多尺度特征的视盘分割方法

针对视盘、视杯分割任务中,由青光眼病变引起目标大小显著变化导致的错误分割问题,提出一种使用更轻量级的编码器-解码器网络,并引入金字塔池化模块,通过网络丰富的感受野捕捉更多上下文特征,丰富尺度特征,充分利用全局信息.在数据集RIM-ONE v.3上进行多组对比实验和评估,实验结果表明,该方法对视盘分割的平均交并比为0.908, Dice系数为0.958,均方误差为0.002,比现有算法各项指标性能均有提高.     

基于CTA图像的两阶段U-Net冠状动脉分割

基于CT血管造影(computed tomography angiography,CTA)图像的冠状动脉自动分割的挑战在于冠状动脉结构复杂、前背景分布严重不平衡,分割时易受冠状静脉和其他组织的干扰.提出了一种两阶段的冠状动脉分割算法,第一阶段采用具有密集特征提取和残差特征修正能力的3D DRU-Net进行分割,保证分割的召回率;在第二阶段提出2D双编码多特征融合U-Net(2D DEMFU-Net)进行细分割,先对原始图像和第一阶段分割结果分别进行特征提取,再采用密集跳跃连接融合两个分支上的多层次语义特征,进一步提高分割准确性.实验结果表明,提出的两阶段分割算法在CortArt2020数据集上的Dice相似系数、召回率和精确度分别优于3D U-Net网络3.83%,5.31%和2.23%.     

基于U1-net网络的放疗脑肿瘤靶区分割

文章基于全卷积神经网络(fully convolutional network, FCN)的U-net网络，并通过对U-net网络的调整，构建适用于脑肿瘤图像分割的U1-net网络。U1-net网络由卷积层、最大池化层、反卷积层和激活函数4个部分组成。通过在公共数据集BRATS 2015上的实验验证了该网络的有效性。实验结果表明，该网络能适应脑肿瘤轮廓取得较好的分割效果，在脑肿瘤的完整肿瘤区、核心肿瘤区、增强肿瘤区的Dice相似系数(Dice similarity coefficient, DSC)分别为0.95、0.85、0.83。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

正~~     

Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has