基于损失加权的实时篮球裁判手势识别系统

为了方便观众更好地在观看比赛直播和录像时理解裁判手势的含义,或帮助录像分析师分析比赛视频,设计了一种实时篮球裁判手势检测与识别系统Yolov5-BR(Yolov5-Basketball Referee).首先,采用目标检测中的Yolov5算法为基础模型,对其边界框的交并比(intersection over union,IoU)损失函数完全交并比(complete intersection over union,CIoU)进行加权处理,增强预测框的鲁棒性;其次,在C3模块后加入注意力机制,产生更具分辨性的特征表示,从而提升网络识别性能;此外,在检测层头部融入自适应特征融合机制,充分利用图像高层语义信息;最后,对目标置信度损失函数进行不对等加权处理,从而提高对小目标检测的鲁棒性.在自制的裁判手势数据集上,Yolov5-BR取得了95.4%的mAP值,本地视频检测速率为55.5帧/s,外接摄像头分辨率为1 280×960,检测速率为25帧/s.实验结果表明,Yolov5-BR相对于原始模型在检测裁判手势的性能上有所提升,保持了较高的准确率、稳定性与实时性.     

面向电网人员智能调度的实景巡检算法

为提高实景巡检中绝缘子缺陷的检测精度,该文提出一种基于双路注意力通道的YOLOv5(Double squeeze and excitation-you only look once version 5,DSE-YOLOv5)算法。该算法使用K-means聚类算法优化先验框参数,提高先验框与目标的匹配度;并对YOLOv5的骨干网和特征融合网络进行改进,加强对小目标检测能力;最后使用距离交并比损失的非极大值抑制(Non-max suppression using distance intersection over union, DIoU-NMS)进行检测。试验结果表明,与传统YOLOv5相比,所提DSE-YOLOv5在对绝缘子缺陷的检测上精准率、召回率、平均精度均值都有提升,满足了电网维修人员在智能调度时对识别精准度的需求。     

煤矿井下钻孔裂隙识别技术

为研究采区煤岩体中裂隙、断裂、破碎带等结构面的自动检测技术,解决现有人工智能技术中迭代次数大、检测框准确度低等问题,采用YOLOv5算法融合注意力机制、损失函数、多尺度检测的方法,对煤矿巷道上顶板5种不同地质钻孔进行裂隙检测试验。结果表明：将注意力机制SENet引入YOLOv5模型框架,避免了图像背景区域与裂隙区域相似度较高问题;采用有效交并比损失函数代替完全交并比损失函数,使得预测框能够更加有效拟合真实目标框;对YOLOv5模型增添3种不同尺寸的锚定框并添加160×160特征层,实现检测更小的目标。该方法与SSD、YOLOv5等检测算法在同样条件下相比,其检测精度分别提升了18.9%,2.1%,召回率提升了39.5%,1.6%,平均精度提升了28.1%,1.0%。改进后的模型将三尺度检测变为四尺度检测,提升了算法的多尺度目标检测性能,能够对钻孔裂隙进行高精度检测,满足钻孔裂隙实时检测需求。     

基于改进YOLOv5的绝缘子缺陷检测算法

绝缘子缺陷检测是电网巡检过程中重要的一环,为提高绝缘子缺陷检测的精度,该文提出一种基于改进YOLOv5算法的绝缘子缺陷检测算法——YOLOv5t,能够在保证网络运行速度的条件下,提升网络的检测精度.该算法在YOLOv5s的基础上,将三重注意力机制(triplet attention)添加到骨干网络中,给予每个特征通道不同的权重,以提高网络的检测精度;并采用CIoU Loss作为网络回归损失的损失函数,提升网络的收敛速度;同时将Soft-NMS作为网络的预测结果处理方法,降低网络的漏检率.YOLOv5t与几种常用的缺陷检测网络的对比实验结果表明,YOLOv5t的准确率达到97.2%,召回率达到98%,平均精度均值达到99.1%,较YOLOv5s算法分别提升了0.9%、5.1%和2.1%,并且检测速度没有受到影响.     

基于改进YOLOv5的鱼眼图像目标检测算法

针对自动驾驶场景下车载鱼眼相机采集到的图像存在畸变严重、场景复杂、尺度变化剧烈、小目标多以及传统的目标检测模型的检测精度不高的问题,提出了一种基于YOLOv5s改进的鱼眼图像检测模型YOLOv5s-R.首先,为解决小目标难识别的问题,提出随机裁剪多尺度训练的数据增强方法,该方法优于消融实验所得的最优数据增强方法.其次,为了提高模型的检测精度,在网络头部添加置换注意力机制与轻量化解耦头,增强模型对特征的提取能力与识别能力,并抑制噪声干扰.最后,模型额外增加角度预测项,实现旋转框目标检测.通过构建环形标签并用高斯函数对标签平滑,解决了旋转框角度的周期性问题;又对损失函数进行了优化,提出了RIOU,在CIOU的基础上增加角度惩罚项,提高了回归精度并加快了模型的收敛.实验结果表明,提出的YOLOv5s-R模型在WoodScape数据集上取得良好的检测效果,相比于原始的YOLOv5s模型,mAP@0.5、mAP@0.5∶0.95分别提升了6.8%、5.6%,达到82.6%、49.5%.     

基于距离交并比回归的孪生网络目标跟踪算法

为解决视频目标跟踪过程中目标框和预测框边界不重叠情况下无法优化的问题,提出了一种距离交并比(distance intersection over union, DIOU)回归的孪生网络目标跟踪算法.通过孪生网络和区域建议网络(region proposal network, RPN)保持实时效果,将距离交并比引入回归分支,结合重叠率和中心点距离构建损失度量,加快模型训练的收敛速度,为边界框提供更直接的回归方向.同时,使用Resnet50网络替换SiamRPN网络的特征提取网络,进一步提高目标特征表示的准确性.实验结果表明,DIOU回归损失在视频目标尺度变化、低分辨率、光照变化等干扰情况下,具有较强鲁棒性.     

基于多尺度融合增强的服装图像解析方法

基于卷积神经网络中的各个层次特征,提出了一种基于多尺度融合增强的服装图像解析方法。通过融合增强模块,在考虑全局信息的基础上对包含的语义信息和不同尺度特征进行有效融合。结果表明：在Fashion Clothing测试集上的平均F1分数达到60.57%,在LIP（Look Into Person）验证集上的平均交并比（mean intersection over union,MIoU）达到54.93%。该方法可以有效地提升服装图像解析精度。     

基于改进YOLOv5的变电站表计缺陷检测算法

准确检测变电站中的设备缺陷并及时进行处理是保证电力系统安全运行的重要措施.针对表计缺陷图像背景复杂、目标尺寸不一、外形差别大等问题,提出基于改进YOLOv5(you only look once的第5个版本)的变电站表计缺陷检测算法.为了提高泛化能力、解决训练过程中样本不平衡问题,利用旋转和改变图像亮度的方法进行数据增广.通过引入坐标注意力机制,在聚焦缺陷特征的同时,能突出缺陷特征的差异.为了使边界框回归更快速准确,将EDIOU loss(effective distance intersection over union loss)代替CIOU loos(complete intersection over union loss).实验结果表明：6种算法中,该文算法的准确度、召回率和mAP(mean average preciscion)均最高,分别达85.1%, 86.6%, 87.3%.因此,该文算法具有优越性.     

改进YOLOv5网络模型的车位检测方法

针对目前车位检测方法效率低的问题，提出一种轻量级车位检测方法OG-YOLOv5。首先，基于YOLOv5网络添加车位分隔线方位回归分支，实现车位方位的准确预测，可直接根据网络预测结果推断完整车位信息；其次，通过检测尺度裁剪、Ghost模块重构网络实现模型轻量化；再者，通过在网络主干中引入ECA注意力机制、优化损失函数提高目标预测精度。通过对比实验，结果表明所提OG-YOLOv5网络的mAP达到了98.8%，模型参数量和计算量仅为原模型的32.0%和28.3%，在GPU和CPU上的检测时间分别减少了16.2%和28.1%，车位检测准确率和召回率分别达到了97.75%和96.87%。     

基于改进DeepLabV3+网络的坝面裂缝检测方法

基于图像分析的水电站坝面缺陷判别是一种高效、精准的方法，然而大坝裂缝图像存在背景复杂以及裂缝和背景像素比例不均衡等问题，导致传统算法的检测效果差。该文提出一种基于改进的DeepLabV3+网络模型的坝面裂缝检测方法。该方法利用三线注意力模块(three line attention module,TLAM)提高模型对裂缝像素的提取能力；采用空洞空间金字塔池化(atrous spatial pyramid pooling,ASPP)模块进行级联优化，实现更密集的像素采样，获取更丰富的裂缝特征；将MobileNetV2作为特征提取主干网络，可实现网络轻量化并减少模型参数；将焦点损失(focal loss,FL)和Dice损失(Dice loss,DL)作为模型的损失函数，可克服数据不平衡的困难。对西南某水电站的坝面裂缝数据集进行模型有效性和对比实验，结果表明：该方法中用来评价模型精度的F_{1, score}、平均交并比(mean intersection over union,MIoU)和平均像素精度(mean pixel accuracy,MPA)的值分别达到73.98...     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

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~~