Hyperparameter

超参数
  • 文章类型: Journal Article
    利用深度学习网络进行语义分割已成为从高分辨率遥感图像中提取目标的重要方法。与传统的卷积神经网络(CNN)相比,VisionTransformer网络在语义分割方面的性能显着提高。视觉转换器网络具有与CNN不同的架构。映像修补程序,线性嵌入,多头自我注意力(MHSA)是几个主要的超参数。我们应该如何配置它们以提取VHR图像中的对象以及它们如何影响网络的准确性是尚未得到充分研究的主题。本文探讨了视觉变压器网络在从极高分辨率(VHR)图像中提取建筑物足迹中的作用。设计并比较了具有不同超参数值的变压器模型,并分析了它们对准确性的影响。结果表明,较小的图像块和较高维嵌入可以获得更好的精度。此外,基于Transformer的网络被证明是可扩展的,并且可以使用具有与卷积神经网络相当的模型大小和训练时间的通用规模图形处理单元(GPU)进行训练,同时实现更高的精度。该研究为视觉变压器网络在使用VHR图像进行对象提取中的潜力提供了有价值的见解。
    Semantic segmentation with deep learning networks has become an important approach to the extraction of objects from very high-resolution remote sensing images. Vision Transformer networks have shown significant improvements in performance compared to traditional convolutional neural networks (CNNs) in semantic segmentation. Vision Transformer networks have different architectures to CNNs. Image patches, linear embedding, and multi-head self-attention (MHSA) are several of the main hyperparameters. How we should configure them for the extraction of objects in VHR images and how they affect the accuracy of networks are topics that have not been sufficiently investigated. This article explores the role of vision Transformer networks in the extraction of building footprints from very-high-resolution (VHR) images. Transformer-based models with different hyperparameter values were designed and compared, and their impact on accuracy was analyzed. The results show that smaller image patches and higher-dimension embeddings result in better accuracy. In addition, the Transformer-based network is shown to be scalable and can be trained with general-scale graphics processing units (GPUs) with comparable model sizes and training times to convolutional neural networks while achieving higher accuracy. The study provides valuable insights into the potential of vision Transformer networks in object extraction using VHR images.
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  • 文章类型: Journal Article
    可采用国际粗糙度指数(IRI)来评价路面的平整度。先前提出的机械经验路面设计指南(MEPDG),用于模拟接缝素混凝土路面(JPCP)的IRI,考虑到其预测精度低的缺点,本研究对此进行了修改。为了提高JPCPIRI预测效果的可靠性,本研究通过使用支持向量机(SVM)的机器学习方法,比较了JPCP的IRI预测精度,决策树(DT),和随机森林(RF),通过甲虫天线搜索(BAS)算法的超参数优化。机器学习过程的结果表明,BAS算法能有效提高超参数整定的有效性,提高优化的速度和准确性。RF模型被证明是上述三种模型中预测精度最高的模型。最后,本研究分析了输入变量对IRI的重要性得分,结果表明,IRI与本研究中的所有输入变量成正比,JPCP的IRI的初始平滑度(IRII)和每km累积的总节理断层(TFAULT)的重要性得分最高。
    The international roughness index (IRI) can be employed to evaluate the smoothness of pavement. The previously proposed mechanical-empirical pavement design guide (MEPDG), which is used to model the IRI of joint plain concrete pavement (JPCP), has been modified in this study considering its disadvantage of low prediction accuracy. To improve the reliability of the prediction effect of the IRI for JPCP, this study compares the prediction accuracy of the IRI of JPCP by using the machine-learning methods of support vector machine (SVM), decision tree (DT), and random forest (RF), optimized by the hyperparameter of the beetle antennae search (BAS) algorithm. The results from the machine-learning process show that the BAS algorithm can effectively improve the effectiveness of hyperparameter tuning, and then improve the speed and accuracy of optimization. The RF model proved to be the one with the highest prediction accuracy among the above three models. Finally, this study analyzes the importance score of input variables to the IRI, and the results show that the IRI was proportional to all the input variables in this study, and the importance score of initial smoothness (IRII) and total joint faulting cumulated per km (TFAULT) were the highest for the IRI of JPCP.
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  • 文章类型: Journal Article
    背景:基于卷积神经网络(CNNSCA)的侧通道密码分析方法可以有效地进行密码攻击。实现密码分析的CNNSCA网络模型主要包括基于VGG变体的CNNSCA(VGG-CNNSCA)和基于Alexnet变体的CNNSCA(Alex-CNNSCA)。这些CNNSCA模型的学习能力和密码分析性能并不理想,并且训练后的模型精度较低,训练时间太长,并占用更多的计算资源。为了提高CNNSCA的整体性能,本文将改进CNNSCA模型设计和超参数优化。
    方法:本文首先研究了SCA应用场景中的CNN架构组成,并推导了CNN核心算法对一维数据侧信道泄漏的计算过程。其次,综合运用VGG-CNNSCA模型分类、拟合效率和Alex-CNNSCA模型占用计算资源少的优势,设计了一种新的CNNSCA基础模型,为了更好地减少深度网络中误差反向传播的梯度色散问题,SE(挤压和激励)模块新嵌入到这个基本模型中,该模块首次在CNNSCA模型中使用,形成了CNNSCA模型设计的新思路。然后将此基本模型应用于来自边信道泄漏公共数据库(ASCAD)的已知一阶屏蔽数据集。在此应用场景中,根据模型设计规则和实际实验结果,排除非必要的实验参数。在最客观的实验参数区间内优化基本模型的各种超参数,提高其密码分析性能,这导致了超参数优化方案和确定超参数的最终基准。
    结果:最后,获得了一种新的CNNSCA模型优化架构,用于攻击未受保护的加密设备-CNNSCAnew。通过对比实验,CNNSCAnew的猜测熵评价结果收敛到61。从模型训练到成功恢复的关键,总时间缩短到30分钟左右,我们获得了比其他CNNSCA模型更好的性能。
    BACKGROUND: The side-channel cryptanalysis method based on convolutional neural network (CNNSCA) can effectively carry out cryptographic attacks. The CNNSCA network models that achieve cryptanalysis mainly include CNNSCA based on the VGG variant (VGG-CNNSCA) and CNNSCA based on the Alexnet variant (Alex-CNNSCA). The learning ability and cryptanalysis performance of these CNNSCA models are not optimal, and the trained model has low accuracy, too long training time, and takes up more computing resources. In order to improve the overall performance of CNNSCA, the paper will improve CNNSCA model design and hyperparameter optimization.
    METHODS: The paper first studied the CNN architecture composition in the SCA application scenario, and derives the calculation process of the CNN core algorithm for side-channel leakage of one-dimensional data. Secondly, a new basic model of CNNSCA was designed by comprehensively using the advantages of VGG-CNNSCA model classification and fitting efficiency and Alex-CNNSCA model occupying less computing resources, in order to better reduce the gradient dispersion problem of error back propagation in deep networks, the SE (Squeeze-and-Excitation) module is newly embedded in this basic model, this module is used for the first time in the CNNSCA model, which forms a new idea for the design of the CNNSCA model. Then apply this basic model to a known first-order masked dataset from the side-channel leak public database (ASCAD). In this application scenario, according to the model design rules and actual experimental results, exclude non-essential experimental parameters. Optimize the various hyperparameters of the basic model in the most objective experimental parameter interval to improve its cryptanalysis performance, which results in a hyper-parameter optimization scheme and a final benchmark for the determination of hyper-parameters.
    RESULTS: Finally, a new CNNSCA model optimized architecture for attacking unprotected encryption devices is obtained-CNNSCAnew. Through comparative experiments, CNNSCAnew\'s guessing entropy evaluation results converged to 61. From model training to successful recovery of the key, the total time spent was shortened to about 30 min, and we obtained better performance than other CNNSCA models.
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  • 文章类型: Journal Article
    OBJECTIVE: The Bayesian first-order antedependence models, which specified single nucleotide polymorphisms (SNP) effects as being spatially correlated in the conventional BayesA/B, had more accurate genomic prediction than their corresponding classical counterparts. Given advantages of BayesCπ over BayesA/B, we have developed hyper-BayesCπ, ante-BayesCπ, and ante-hyper-BayesCπ to evaluate influences of the antedependence model and hyperparameters for vg and sg2 on BayesCπ.
    METHODS: Three public data (two simulated data and one mouse data) were used to validate our proposed methods. Genomic prediction performance of proposed methods was compared to traditional BayesCπ, ante-BayesA and ante-BayesB.
    RESULTS: Through both simulation and real data analyses, we found that hyper-BayesCπ, ante-BayesCπ and ante-hyper-BayesCπ were comparable with BayesCπ, ante-BayesB, and ante-BayesA regarding the prediction accuracy and bias, except the situation in which ante-BayesB performed significantly worse when using a few SNPs and π = 0.95.
    CONCLUSIONS: Hyper-BayesCπ is recommended because it avoids pre-estimated total genetic variance of a trait compared with BayesCπ and shortens computing time compared with ante-BayesB. Although the antedependence model in BayesCπ did not show the advantages in our study, larger real data with high density chip may be used to validate it again in the future.
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