Identification Model of Pi2 Pulsation Based on One-dimensional Residual Convolutional Neural Network
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摘要: Pi2脉动是一种不规则的超低频波(Ultra-Low Frequency, ULF), 是磁层与电离层耦合的重要瞬态响应, 其发生与亚暴爆发有密切的关系. Pi2脉动作为地球磁层中的一种扰动现象, 其发生信号隐藏在地磁场分量观测数据中. 面对持续增长的观测数据量, 如何有效地判断某段地磁场分量观测数据中是否有Pi2脉动发生, 是构建Pi2脉动识别模型的关键. 利用子午工程磁通门磁力仪观测的地磁场分量数据, 基于一维残差卷积神经网络(One-Dimensional Residual Convolutional Neural Network, 1D-ResCNN), 构建了一个端到端的Pi2脉动识别模型, 用于判别某段地磁场分量观测数据中是否有Pi2脉动发生. 实验结果表明, 该模型与现有公开发表的Pi2脉动机器学习识别模型相比, 具有更高的识别准确率和更低的虚报率、漏报率.
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关键词:
- Pi2脉动 /
- Pi2脉动识别模型 /
- 一维残差卷积神经网络
Abstract: Pi2 pulsations are irregular ultra-low frequency waves, representing a significant transient response to the coupling between the magnetosphere and ionosphere. Their occurrence is associated with onset of substorms. As a disturbance phenomenon in the Earth’s magnetosphere, the occurrence signal of Pi2 pulsations is hidden within the observation data of geomagnetic field components. Addressing the increasing amount of observation data, how to efficiently determine whether Pi2 pulsation has occurred in a segment of geomagnetic field component observational data is the key to build a Pi2 pulsation identification model. Based on the time series observation data of the FGM from the Chinese Meridian Project and One-Dimensional Residual Convolutional Neural Network (1D-ResCNN), this paper establishes an end-to-end Pi2 pulsation identification model. This model can distinguish whether Pi2 pulsation occurs in the observation data of a certain geomagnetic field component. Experimental results show that this model has higher recognition accuracy and lower false positive rate and false negative rate than the existing Pi2 pulsation machine learning identification model. -
表 1 漠河站Dataset1的正负样本分布情况
Table 1. Positive and negative sample distribution of Dataset1 at MHT
窗口长度/min 训练集 验证集 测试集 正样本 负样本 正样本 负样本 正样本 负样本 10 13320 216936 6524 89668 10061 146323 20 10855 104273 5223 42873 8071 70121 40 8477 49087 3977 20071 6195 32901 表 2 漠河站Dataset2的正负样本分布情况
Table 2. Positive and negative sample distribution of Dataset2 at MHT
窗口长度/min 训练集 验证集 测试集 正样本 负样本 正样本 负样本 正样本 负样本 10 14662 221925 6232 95163 9011 135839 20 11737 106556 5170 45528 7242 65183 40 9188 49958 3844 21505 5617 30596 表 3 混淆矩阵
Table 3. Confusion matrix
预测类别 真实标签 正例 正例 正例 TP FP 负例 FN TN 表 4 使用策略1的不同模型在Dataset1和Dataset2测试集上的实验结果
Table 4. Experimental results on testing Dataset1 and Dataset2 of different models with Decision 1
模型 窗口长度/min 准确率/(%) 虚报率/(%) 漏报率/(%) $ {F}_{1} $值 FT+MLP[11] 10 95.63, 95.76 1.05, 0.98 52.68, 53.39 0.58, 0.58 20 93.75, 94.04 1.73, 1.69 45.58, 44.35 0.64, 0.65 40 88.41, 88.45 2.77, 2.27 58.39, 62.08 0.5, 0.50 DWT+CNN[12] 10 95.90, 95.89 0.06, 0.05 62.83, 65.28 0.54, 0.51 20 93.89, 94.33 0.11, 0.18 58.26, 55.12 0.58, 0.61 40 92.43, 91.59 0.69, 0.21 44.10, 53.07 0.70, 0.63 1D-ResCNN(本文方法) 10 97.84, 97.86 0.83, 0.96 21.64, 19.80 0.82, 0.82 20 96.89, 97.13 1.41, 1.23 17.85, 17.70 0.85, 0.85 40 95.71, 95.82 1.85, 1.82 17.21, 16.98 0.86, 0.86 表 5 使用策略2的不同模型在Dataset1和Dataset2测试集上的实验结果
Table 5. Experimental results on testing Dataset1 and Dataset2 of different models with Decision2
模型 窗口长度/min 决策阈值 准确率/(%) 虚报率/(%) 漏报率/(%) $ {F}_{1} $值 FT+MLP[11] 10 0.29, 0.25 95.24, 95.25 2.43, 2.67 38.72, 36.10 0.62, 0.63 20 0.33, 0.31 93.52, 93.55 3.25, 3.65 34.48, 31.63 0.68, 0.68 40 0.29, 0.27 86.80, 87.19 8.38, 7.91 38.81, 39.51 0.60, 0.59 DWT+CNN[12] 10 0.27, 0.27 96.98, 97.13 1.89, 1.53 19.39, 23.02 0.77, 0.77 20 0.27, 0.28 96.09, 94.33 2.00, 2.20 20.53, 21.55 0.81, 0.79 40 0.29, 0.27 93.55, 94.10 3.78, 3.22 20.61, 20.53 0.80, 0.81 1D-ResCNN 10 0.38, 0.43 97.77, 97.84 1.25, 1.17 16.41, 17.17 0.83, 0.83 (本文方法) 20 0.40, 0.38 96.81, 97.06 1.87, 1.76 14.65, 13.62 0.85, 0.85 40 0.42, 0.35 95.73, 95.76 2.26, 2.74 14.98, 12.43 0.86, 0.86 表 6 不同台站的基本信息及样本分布情况
Table 6. Basic information and samples distribution of different stations
台站名称 (编码) 地磁坐标 训练集 验证集 测试集 正样本 负样本 正样本 负样本 正样本 负样本 琼中站 (QZT) (16°48′ , 182°0′ ) 1845 9772 748 4231 5944 31784 邵阳站 (SYT) (23°54′ , 183°55′ ) 1611 12929 675 5557 5190 41070 马陵山站 (MLS) (29°25′ , 191°21′ ) 1522 12388 680 5282 3710 30634 农安站 (NAT) (39°0′ , 198°5′ ) 1923 14381 859 6129 5252 38020 表 7 不同台站的测试集的实验结果
Table 7. Experimental results on testing datasets of stations at different latitudes
台站名称 (编码) 准确率/(%) 虚报率/(%) 漏报率/(%) $ {F}_{1} $值 琼中站 (QZT) 90.73 8.64 12.63 0.75 邵阳站 (SYT) 95.81 1.77 23.35 0.80 马陵山站 (MLS) 95.86 1.96 22.16 0.80 农安站 (NAT) 95.76 1.88 21.27 0.82 -
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