The dynamic transmission characteristics and the sensitivities of the three stage idler gear system of the new NC power turret are studied in the paper. Considering the strongly nonlinear factors such as the periodica...The dynamic transmission characteristics and the sensitivities of the three stage idler gear system of the new NC power turret are studied in the paper. Considering the strongly nonlinear factors such as the periodically time-varying mesh stiffness, the nonlinear tooth backlash, the lump-parameter model of the gear system is developed with one rotational and two translational freedoms of each gear. The eigen-values and eigenvectors are derived and analyzed on the basis of the real modal theory. The sensitivities of natural frequencies to design parameters including supporting and meshing stiffnesses, gear masses, and moments of inertia by the direct differential method are also calculated. The results show the quantitative and qualitative impact of the parameters to the natural characteristics of the gear system. Furthermore, the periodic steady state solutions are obtained by the numerical approach based on the nonlinear model. These results are employed to gain insights into the primary controlling parameters, to forecast the severity of the dynamic response, and to assess the acceptability of the gear design.展开更多
A novel multi level image segmentation methodology is been proposed with the aim of extracting the salient object,keeping in view,only a small part of the visual scene undergoes attention and reaches the level of awar...A novel multi level image segmentation methodology is been proposed with the aim of extracting the salient object,keeping in view,only a small part of the visual scene undergoes attention and reaches the level of awareness while rest of details are futile.Taking advantage of multilevel gray scale quantization,image prominent object is separated from background,keeping in view the fact;salient object is having high contrast as compared to the background.The inutile fragments were removed using morphological operations of opening and closing and making the image smoothened with Gaussian filter.The optimum threshold is selected for the binary conversion and final extrication of the salient object from the image.The experimental data indicates that hybrid approach leads to improved segmentation with the apparent assertion of prime object extraction.展开更多
语义分割技术能够对复杂、多元的场景实现细粒度理解,是促进无人系统高效、智能工作的关键技术之一.大规模无监督语义分割旨在从大规模未标记图像中学习语义分割能力.然而,现有方法由于自学习伪标签存在类别混淆和形状表示欠佳的问题,...语义分割技术能够对复杂、多元的场景实现细粒度理解,是促进无人系统高效、智能工作的关键技术之一.大规模无监督语义分割旨在从大规模未标记图像中学习语义分割能力.然而,现有方法由于自学习伪标签存在类别混淆和形状表示欠佳的问题,导致最终分割精度较低.为此,本文提出一种伪标签去噪和SAM优化(Pseudo-label Denoising and SAM Optimization,PDSO)方法以解决大规模无监督语义分割问题.本文设计了一种基于去噪的特征微调模块,在基于小损失准则从大规模数据集中筛选出具有干净图像级伪标签的潜在样本后,利用这些干净样本对预训练的主干网络进行微调,使网络获得更稳健的类别表示.为了进一步减少伪标签中的类别噪声,设计了一种基于聚类的样本去噪模块,根据类别占比和样本与聚类中心之间的距离来去除干扰聚类任务的噪声样本,从而提升聚类性能.本文还设计了一种SAM提示优化模块,根据聚类距离识别出图像中的活跃类别,以过滤噪声目标,并将点和框作为SAM的目标提示信息,生成预期的目标掩膜以细化伪标签中目标的边缘.实验结果表明,在大规模语义分割数据集ImageNet-S_(50)、ImageNet-S_(300)和ImageNet-S_(919)的测试集上,本文方法在平均交并比指标上分别达到了45.0%、26.6%和14.5%,显著提高了分割目标的类别准确率和边缘精度.展开更多
文摘The dynamic transmission characteristics and the sensitivities of the three stage idler gear system of the new NC power turret are studied in the paper. Considering the strongly nonlinear factors such as the periodically time-varying mesh stiffness, the nonlinear tooth backlash, the lump-parameter model of the gear system is developed with one rotational and two translational freedoms of each gear. The eigen-values and eigenvectors are derived and analyzed on the basis of the real modal theory. The sensitivities of natural frequencies to design parameters including supporting and meshing stiffnesses, gear masses, and moments of inertia by the direct differential method are also calculated. The results show the quantitative and qualitative impact of the parameters to the natural characteristics of the gear system. Furthermore, the periodic steady state solutions are obtained by the numerical approach based on the nonlinear model. These results are employed to gain insights into the primary controlling parameters, to forecast the severity of the dynamic response, and to assess the acceptability of the gear design.
文摘A novel multi level image segmentation methodology is been proposed with the aim of extracting the salient object,keeping in view,only a small part of the visual scene undergoes attention and reaches the level of awareness while rest of details are futile.Taking advantage of multilevel gray scale quantization,image prominent object is separated from background,keeping in view the fact;salient object is having high contrast as compared to the background.The inutile fragments were removed using morphological operations of opening and closing and making the image smoothened with Gaussian filter.The optimum threshold is selected for the binary conversion and final extrication of the salient object from the image.The experimental data indicates that hybrid approach leads to improved segmentation with the apparent assertion of prime object extraction.
文摘语义分割技术能够对复杂、多元的场景实现细粒度理解,是促进无人系统高效、智能工作的关键技术之一.大规模无监督语义分割旨在从大规模未标记图像中学习语义分割能力.然而,现有方法由于自学习伪标签存在类别混淆和形状表示欠佳的问题,导致最终分割精度较低.为此,本文提出一种伪标签去噪和SAM优化(Pseudo-label Denoising and SAM Optimization,PDSO)方法以解决大规模无监督语义分割问题.本文设计了一种基于去噪的特征微调模块,在基于小损失准则从大规模数据集中筛选出具有干净图像级伪标签的潜在样本后,利用这些干净样本对预训练的主干网络进行微调,使网络获得更稳健的类别表示.为了进一步减少伪标签中的类别噪声,设计了一种基于聚类的样本去噪模块,根据类别占比和样本与聚类中心之间的距离来去除干扰聚类任务的噪声样本,从而提升聚类性能.本文还设计了一种SAM提示优化模块,根据聚类距离识别出图像中的活跃类别,以过滤噪声目标,并将点和框作为SAM的目标提示信息,生成预期的目标掩膜以细化伪标签中目标的边缘.实验结果表明,在大规模语义分割数据集ImageNet-S_(50)、ImageNet-S_(300)和ImageNet-S_(919)的测试集上,本文方法在平均交并比指标上分别达到了45.0%、26.6%和14.5%,显著提高了分割目标的类别准确率和边缘精度.
