Underwater acoustic signal processing is one of the research hotspots in underwater acoustics.Noise reduction of underwater acoustic signals is the key to underwater acoustic signal processing.Owing to the complexity ...Underwater acoustic signal processing is one of the research hotspots in underwater acoustics.Noise reduction of underwater acoustic signals is the key to underwater acoustic signal processing.Owing to the complexity of marine environment and the particularity of underwater acoustic channel,noise reduction of underwater acoustic signals has always been a difficult challenge in the field of underwater acoustic signal processing.In order to solve the dilemma,we proposed a novel noise reduction technique for underwater acoustic signals based on complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN),minimum mean square variance criterion(MMSVC) and least mean square adaptive filter(LMSAF).This noise reduction technique,named CEEMDAN-MMSVC-LMSAF,has three main advantages:(i) as an improved algorithm of empirical mode decomposition(EMD) and ensemble EMD(EEMD),CEEMDAN can better suppress mode mixing,and can avoid selecting the number of decomposition in variational mode decomposition(VMD);(ii) MMSVC can identify noisy intrinsic mode function(IMF),and can avoid selecting thresholds of different permutation entropies;(iii) for noise reduction of noisy IMFs,LMSAF overcomes the selection of deco mposition number and basis function for wavelet noise reduction.Firstly,CEEMDAN decomposes the original signal into IMFs,which can be divided into noisy IMFs and real IMFs.Then,MMSVC and LMSAF are used to detect identify noisy IMFs and remove noise components from noisy IMFs.Finally,both denoised noisy IMFs and real IMFs are reconstructed and the final denoised signal is obtained.Compared with other noise reduction techniques,the validity of CEEMDAN-MMSVC-LMSAF can be proved by the analysis of simulation signals and real underwater acoustic signals,which has the better noise reduction effect and has practical application value.CEEMDAN-MMSVC-LMSAF also provides a reliable basis for the detection,feature extraction,classification and recognition of underwater acoustic signals.展开更多
为解决光伏序列的强噪音干扰以及单一模型在光伏功率预测方面精度偏低和泛化性较差的问题,提出了一种基于特征优化和混合改进灰狼算法优化双向长短时记忆网络(bi-directional long short-term memory,BiLSTM)的短期光伏功率预测方法。首...为解决光伏序列的强噪音干扰以及单一模型在光伏功率预测方面精度偏低和泛化性较差的问题,提出了一种基于特征优化和混合改进灰狼算法优化双向长短时记忆网络(bi-directional long short-term memory,BiLSTM)的短期光伏功率预测方法。首先,运用互信息算法进行输入数据的变量选择,以消除冗余变量。其次,通过互补集合经验模态分解和改进的小波阈值算法对筛选后的数据进行特征重构,旨在降低数据中的噪声干扰并完成输入变量的特征优化。随后,结合改进的Tent混沌映射、非线性递减因子、动态权重策略和差分进化算法对标准灰狼优化算法进行混合优化,以确定双向长短期记忆神经网络的最优超参数组合,并引入注意力机制以挖掘数据中的关键时序信息,最终构建出一种新型的短期光伏功率预测模型。仿真实验表明,相较于最小二乘支持向量机、长短期记忆网络和双向长短期记忆网络,所提模型在晴天、多云、阴天和降雨等不同工况下的均方根误差平均分别降低了12.45%、7.95%和5.37%,显示出优秀的预测性能、良好的泛化能力和潜在的工程应用价值。展开更多
基金The authors gratefully acknowledge the support of the National Natural Science Foundation of China(No.11574250).
文摘Underwater acoustic signal processing is one of the research hotspots in underwater acoustics.Noise reduction of underwater acoustic signals is the key to underwater acoustic signal processing.Owing to the complexity of marine environment and the particularity of underwater acoustic channel,noise reduction of underwater acoustic signals has always been a difficult challenge in the field of underwater acoustic signal processing.In order to solve the dilemma,we proposed a novel noise reduction technique for underwater acoustic signals based on complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN),minimum mean square variance criterion(MMSVC) and least mean square adaptive filter(LMSAF).This noise reduction technique,named CEEMDAN-MMSVC-LMSAF,has three main advantages:(i) as an improved algorithm of empirical mode decomposition(EMD) and ensemble EMD(EEMD),CEEMDAN can better suppress mode mixing,and can avoid selecting the number of decomposition in variational mode decomposition(VMD);(ii) MMSVC can identify noisy intrinsic mode function(IMF),and can avoid selecting thresholds of different permutation entropies;(iii) for noise reduction of noisy IMFs,LMSAF overcomes the selection of deco mposition number and basis function for wavelet noise reduction.Firstly,CEEMDAN decomposes the original signal into IMFs,which can be divided into noisy IMFs and real IMFs.Then,MMSVC and LMSAF are used to detect identify noisy IMFs and remove noise components from noisy IMFs.Finally,both denoised noisy IMFs and real IMFs are reconstructed and the final denoised signal is obtained.Compared with other noise reduction techniques,the validity of CEEMDAN-MMSVC-LMSAF can be proved by the analysis of simulation signals and real underwater acoustic signals,which has the better noise reduction effect and has practical application value.CEEMDAN-MMSVC-LMSAF also provides a reliable basis for the detection,feature extraction,classification and recognition of underwater acoustic signals.
文摘为解决光伏序列的强噪音干扰以及单一模型在光伏功率预测方面精度偏低和泛化性较差的问题,提出了一种基于特征优化和混合改进灰狼算法优化双向长短时记忆网络(bi-directional long short-term memory,BiLSTM)的短期光伏功率预测方法。首先,运用互信息算法进行输入数据的变量选择,以消除冗余变量。其次,通过互补集合经验模态分解和改进的小波阈值算法对筛选后的数据进行特征重构,旨在降低数据中的噪声干扰并完成输入变量的特征优化。随后,结合改进的Tent混沌映射、非线性递减因子、动态权重策略和差分进化算法对标准灰狼优化算法进行混合优化,以确定双向长短期记忆神经网络的最优超参数组合,并引入注意力机制以挖掘数据中的关键时序信息,最终构建出一种新型的短期光伏功率预测模型。仿真实验表明,相较于最小二乘支持向量机、长短期记忆网络和双向长短期记忆网络,所提模型在晴天、多云、阴天和降雨等不同工况下的均方根误差平均分别降低了12.45%、7.95%和5.37%,显示出优秀的预测性能、良好的泛化能力和潜在的工程应用价值。
