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arXiv 2006.04667cs.LGstat.ML
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基于机器学习的Dst预测新方法--动态时间弯曲

Dynamic Time Warping as a New Evaluation for Dst Forecast with Machine Learning

KU Leuven(鲁汶大学);Centre for mathematical Plasma Astrophysics(数学等离子体天体物理学中心)

Brecht Laperre, Jorge Amaya, Giovanni Lapenta

摘要:

基于神经网络和机器学习的模型在空间物理学中越来越受欢迎。特别是利用神经网络模型对地磁指数进行预测,正成为一个热门的研究领域。这些模型的评估指标,如均方根误差(RMSE)和皮尔逊相关系数。然而,这些经典指标有时无法捕捉关键行为。为了显示缺乏经典指标的地方,我们训练了一个神经网络,使用长短期记忆网络,在原始时间$t$预测扰动风暴时间指数,预测范围为1至6小时,在OMNIWeb数据上训练。检查模型的结果与相关系数和RMSE表明,性能与最新出版物。然而,视觉检查表明,神经网络做出的预测与持久性模型的行为相似。在这项工作中,提出了一种新的方法来衡量两个时间序列是否在时间上相互移动,如持久性模型输出与观察。新的措施,基于动态时间弯曲,是能够识别的持久性模型的结果,并在确认神经网络的输出的视觉观察显示有前途的结果。最后,探讨了不同的方法来训练神经网络,以消除持久性行为的结果。

英文摘要:

Models based on neural networks and machine learning are seeing a rise in popularity in space physics. In particular, the forecasting of geomagnetic indices with neural network models is becoming a popular field of study. These models are evaluated with metrics such as the root-mean-square error (RMSE) and Pearson correlation coefficient. However, these classical metrics sometimes fail to capture crucial behavior. To show where the classical metrics are lacking, we trained a neural network, using a long short-term memory network, to make a forecast of the disturbance storm time index at origin time $t$ with a forecasting horizon of 1 up to 6 hours, trained on OMNIWeb data. Inspection of the model's results with the correlation coefficient and RMSE indicated a performance comparable to the latest publications. However, visual inspection showed that the predictions made by the neural network were behaving similarly to the persistence model. In this work, a new method is proposed to measure whether two time series are shifted in time with respect to each other, such as the persistence model output versus the observation. The new measure, based on Dynamical Time Warping, is capable of identifying results made by the persistence model and shows promising results in confirming the visual observations of the neural network's output. Finally, different methodologies for training the neural network are explored in order to remove the persistence behavior from the results.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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