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141.
The Coronavirus disease 2019 (COVID-19) has become one of the threats to the world. Computed tomography (CT) is an informative tool for the diagnosis of COVID-19 patients. Many deep learning approaches on CT images have been proposed and brought promising performance. However, due to the high complexity and non-transparency of deep models, the explanation of the diagnosis process is challenging, making it hard to evaluate whether such approaches are reliable. In this paper, we propose a visual interpretation architecture for the explanation of the deep learning models and apply the architecture in COVID-19 diagnosis. Our architecture designs a comprehensive interpretation about the deep model from different perspectives, including the training trends, diagnostic performance, learned features, feature extractors, the hidden layers, the support regions for diagnostic decision, and etc. With the interpretation architecture, researchers can make a comparison and explanation about the classification performance, gain insight into what the deep model learned from images, and obtain the supports for diagnostic decisions. Our deep model achieves the diagnostic result of 94.75%, 93.22%, 96.69%, 97.27%, and 91.88% in the criteria of accuracy, sensitivity, specificity, positive predictive value, and negative predictive value, which are 8.30%, 4.32%, 13.33%, 10.25%, and 6.19% higher than that of the compared traditional methods. The visualized features in 2-D and 3-D spaces provide the reasons for the superiority of our deep model. Our interpretation architecture would allow researchers to understand more about how and why deep models work, and can be used as interpretation solutions for any deep learning models based on convolutional neural network. It can also help deep learning methods to take a step forward in the clinical COVID-19 diagnosis field. 相似文献
142.
海洋重力传感器伺服回路分析与设计 总被引:1,自引:0,他引:1
李宏生 《中国惯性技术学报》2002,10(5):45-49
海洋重力仪是改善舰船惯导系统精度的重要设备,其重力传感器的伺服回路决定着仪器的精度和动态性能。作在介绍零长弹簧海洋重力传感器结构原理的基础上,研究其伺服回路的结构组成和设计方法,分析了其主要环节参数对系统性能的影响,考察了其时域性能,对海洋重力仪的研制具有重要指导作用。 相似文献
143.
Proper permutation of data matrix rows and columns may result in plots showing striking information on the objects and variables under investigation. To control the permutation first, a diagonal matrix measure D was defined expressing the size relations of the matrix elements. D is essentially the absolute norm of a matrix where the matrix elements are weighted by their distance to the matrix diagonal. Changing the order of rows and columns increases or decreases D. Monte Carlo technique was used to achieve maximum D in the case of the object distance matrix or even minimal D in the case of the variable correlation matrix to get similar objects or variables close together. Secondly, a local distance matrix was defined, where an element reflects the distances of neighboring objects in a limited subspace of the variables. Due to the maximization of D in the local distance matrix by row and column changes of the original data matrix, the similar objects were arranged close to each other and simultaneously the variables responsible for their similarity were collected close to the diagonal part defined by these objects. This combination of the diagonal measure and the local distance matrix seems to be an efficient tool in the exploration of hidden similarities of a data matrix. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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介绍了陀螺罗经、平台罗经和惯导等常见船载导航系统,分析了导航系统向伺服系统提供航向和横、纵摇等姿态信息的情况。阐述了船载伺服系统为实现姿态稳定对导航系统相关信号的需求和误差对伺服系统的影响。论述了航向信号接收的相关转换器选型技术要求和特殊转值过零的软件处理流程。给出了为了实现三轴指向稳定而将将船体姿态信号进行坐标变换的一种简单推导过程。 相似文献
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针对传统粒子滤波的目标跟踪算法存在粒子退化问题,提出了基于无味粒子滤波(UPF)的目标跟踪算法。为了将当前观测信息融入,采用无味卡尔曼滤波(UKF)生成粒子滤波的提议分布,以改善滤波效果。针对目标在机动过程中引起的视觉形变以及背景的变化,又采用了颜色直方图作为目标的颜色分布模型,并与UPF相融合。仿真结果表明,该算法对动态场景下的高机动目标有较好的跟踪效果。 相似文献
149.
基于人眼视觉特性的遥感图像融合算法 总被引:1,自引:0,他引:1
首先提出基于非下采样Contourlet变换(NSCT,Nonsubsampled Contourlet Transform)的人眼视觉相对对比度灵敏度函数(RCSF,relative contrast sensitivity function)和绝对对比度灵敏度函数(ACSF,absolute contrast sensitivity function)。然后提出了基于人眼视觉对比度灵敏度函数(CSF,contrast sensitivityfunction)的遥感图像融合算法(IFA-CSF,image fusion algorithmof human visual contrast sensitivity function)。IFA-CSF采用NSCT作为多尺度变换工具,对单方向高频子带采用ACSF融合,对多方向高频子带采用RCSF融合,并对8方向高频子带采用先方向分组再融合的方法。实验结果表明,IFA-CSF优于基于传统CSF和基于局部能量的图像融合算法。 相似文献
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