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利用灰色关联极限学习机预报日长变化

  • [设施]:长短波
  • [期刊/会议名称]:中国科学院大学学报
  • [摘要]:Due to the time-varying characteristics of length-of-day (LOD), it is difficult to model LOD variations with a deterministic model. We employ a new type of artificial neural networks (ANN) extreme learning machine (ELM) to predict LOD variations. In order to solve the problems of embedding dimension selection and network topology design,a training algorithm for ELM based on grey relational analysis (GRA) is first proposed. It optimizes the input and hidden layers simultaneously. Secondly,the values of LOD variation are preprocessed and a GRA-ELM model is then set up to accurately forecast LOD variation in near real-time. Finally,the prediction results are analyzed and compared with those obtained by the back propagation neural networks, generalization regression neural networks and Earth orientation parameters prediction comparison campaign. The results show that the prediction accuracy of our method is equal to or even better than those of the other prediction methods. The developed method is easy to use. Abstract:针对日长变化难以用精确模型进行预报的问题,将一种新型人工神经网络极限学习机(extreme learning machine,ELM)用于日长变化预报中. 首先针对时间序列预测问题中存在的嵌入维数选取和网络结构设计问题,提出一种基于灰色关联分析(grey relational analysis,GRA)的ELM算法(GRA-ELM), 该算法将灰色关联分析输入节点选取嵌入到ELM网络的训练过程中,同时完成嵌入维数和隐层节点规模的确定. 然后根据日长变化数据的特点对其进行预处理,建立一种能够高精度、近实时预报日长变化的GRA-ELM预报模型. 最后将GRA-ELM模型的预报结果同标准ELM、反向传播神经网络、广义回归神经网络和地球定向参数预报比较竞赛的结果进行比较. 结果表明,通过本方法得到的日长变化较其他方法在精度上有较大改善.
  • [发表日期]:2015
  • [第一作者]: 雷雨
  • [第一作者单位]:国家授时中心
  • [通讯作者]: 雷雨
  • [通讯作者单位]:国家授时中心
  • [论文类型]:期刊论文
  • [期刊分类]:CSCD
  • [学科分类]:天文地球动力学
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  • [关键词]:length-of-day (LOD) variations; prediction; grey relational analysis (GRA); extreme learning machine (ELM); neural networks (NN)
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