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基于EMD和改进小波阈值的地震信号去噪方法 被引量:2
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作者 巨鑫 郑小鹏 +3 位作者 武科含 周健 商冬明 徐静霞 《内蒙古石油化工》 CAS 2020年第5期44-49,共6页
地震资料采集获得的地震信号资料中往往夹杂着大量的噪音信息,地震信号的有效去噪对后续的地震资料解释具有重要的意义。本文提出一种基于经验模态分解(Empirical Mode Decomposition,EMD)和改进小波阈值的地震信号去噪方法。将含噪地... 地震资料采集获得的地震信号资料中往往夹杂着大量的噪音信息,地震信号的有效去噪对后续的地震资料解释具有重要的意义。本文提出一种基于经验模态分解(Empirical Mode Decomposition,EMD)和改进小波阈值的地震信号去噪方法。将含噪地震信号分解为一系列本征模态函数(Intrinsic Mode Function,IMF),并根据自相关理论,对从IMFs中筛选的高频分量应用改进的小波高参数阈值算法处理,低频IMF分量应用改进的小波低参数阈值处理,最后对处理后的IMFs进行重构。利用本文提出的地震信号去噪方法对合成地震信号和实际地震信号进行去噪处理,并与EMD去噪效果进行对比,结果均表明本文所提方法的去噪效果优于常规的EMD方法。 展开更多
关键词 地震信号 经验模态分解 小波阈值去噪 去噪 信噪比
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Deep learning models for spatial relation extraction in text
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作者 Kehan Wu Xueying Zhang +1 位作者 Yulong Dang Peng Ye 《Geo-Spatial Information Science》 SCIE EI 2023年第1期58-70,共13页
Spatial relation extraction is the process of identifying geographic entities from text and determining their corresponding spatial relations.Traditional spatial relation extraction mainly uses rule-based pattern matc... Spatial relation extraction is the process of identifying geographic entities from text and determining their corresponding spatial relations.Traditional spatial relation extraction mainly uses rule-based pattern matching,supervised learning-based or unsupervised learning-based methods.However,these methods suffer from poor time-sensitive,high labor cost and high dependence on large-scale data.With the development of pre-trained language models greatly alleviating the shortcomings of traditional methods,supervised learning methods incorporating pre-trained language models have become the mainstream relation extraction methods.Pipeline extraction and joint extraction,as the two most dominant ideas of relation extraction,both have obtained good performance on different datasets,and whether to share the contextual information of entities and relations is the main differences between the two ideas.In this paper,we compare the performance of two ideas oriented to spatial relation extraction based on Chinese corpus data in the field of geography and verify which method based on pre-trained language models is more suitable for Chinese spatial relation extraction.We fine-tuned the hyperparameters of the two models to optimize the extraction accuracy before the comparison experiments.The results of the comparison experiments show that pipeline extraction performs better than joint extraction of spatial relation extraction for Chinese text data with sentence granularity,because different tasks have different focus on contextual information,and it is difficult to take account into the needs of both tasks by sharing contextual information.In addition,we further compare the performance of the two models with the rule-based template approach in extracting topological,directional and distance relations,summarize the shortcomings of this experiment and provide an outlook for future work. 展开更多
关键词 Spatial relation extraction pre-trained language model pipeline extraction joint extraction
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