Wigner-Ville distribution(WVD)is widely used in the field of signal processing due to its excellent time-frequency(TF)concentration.However,WVD is severely limited by the cross-term when working with multicomponent si...Wigner-Ville distribution(WVD)is widely used in the field of signal processing due to its excellent time-frequency(TF)concentration.However,WVD is severely limited by the cross-term when working with multicomponent signals.In this paper,we analyze the property differences between auto-term and cross-term in the one-dimensional sequence and the two-dimensional plane and approximate entropy and Rényi entropy are employed to describe them,respectively.Based on this information,we propose a new method to achieve adaptive cross-term removal by combining seeded region growing.Compared to other methods,the new method can achieve cross-term removal without decreasing the TF concentration of the auto-term.Simulation and experimental data processing results show that the method is adaptive and is not constrained by the type or distribution of signals.And it performs well in low signal-to-noise ratio environments.展开更多
针对舰船辐射噪声低频线谱动态频率精细特征提取存在的频率分辨率低、瞬时频率跟踪性差、频率分析不够精细等问题,提出了一种基于移频频率细化瞬时自相关函数滤波的改进维格纳威利分布(Wigner Ville distribution,WVD)算法Z-FIR-WVD(zoo...针对舰船辐射噪声低频线谱动态频率精细特征提取存在的频率分辨率低、瞬时频率跟踪性差、频率分析不够精细等问题,提出了一种基于移频频率细化瞬时自相关函数滤波的改进维格纳威利分布(Wigner Ville distribution,WVD)算法Z-FIR-WVD(zoom-finite impulse response filter-WVD)。通过对移频降采样瞬时自相关函数在时域进行FIR(finite impulse response)滤波后的信号进行细化分析,可有效提高对WVD中多线谱交叉项干扰的抑制能力和频率分辨能力,实现对低频线谱动态精细特征的有效提取。仿真实验和实测信号验证结果表明,该算法在保持WVD频率聚集性的前提下,可有效抑制交叉项干扰,并实现对低频线谱的高频率分辨率动态分析,为舰船辐射噪声低频线谱动态频率精细特征提取问题提供了一种新的解决方法。展开更多
Wigner-Ville distribution (WVD) is recognized as being a powerful tool and a nucleus in time-frequency representation (TFR) which gives an excellent time-frequency concentration, and more importantly, has many desirab...Wigner-Ville distribution (WVD) is recognized as being a powerful tool and a nucleus in time-frequency representation (TFR) which gives an excellent time-frequency concentration, and more importantly, has many desirable properties. A major shortcoming of WVD is the inherent cross-term (CT) interference. Although solutions to this problem from the bulk of contributions to the literature concerning TFR are currently available, none has been able to completely eliminate the CT’s in WVD. It is therefore a common belief that if there exists an auxiliary time-frequency distribution (TFD) which has the same auto-terms (AT’s) as that in WVD, but has CT’s with the opposite sign, then, by adding the auxiliary TFD to WVD, an ideal TFD, which preserves the concentration of WVD while annihilating the CT’s, is readily obtained. However, we prove that the auxiliary TFD does not exist. Moreover, it is found that in general, CT free joint distributions with their concentrations close to that of WVD do not exist either.展开更多
近年来,利用文本、视觉和音频数据分析视频中说话者情感的多模态情感分析(MSA)引起了广泛关注。然而,不同模态在情感分析中的贡献大不相同。通常,文本中包含的信息更加直观,因此寻求一种用于增强文本在情感分析中作用的策略显得尤为重...近年来,利用文本、视觉和音频数据分析视频中说话者情感的多模态情感分析(MSA)引起了广泛关注。然而,不同模态在情感分析中的贡献大不相同。通常,文本中包含的信息更加直观,因此寻求一种用于增强文本在情感分析中作用的策略显得尤为重要。针对这一问题,提出一种跨模态文本信息增强的多模态情感分析模型(MSAMCTE)。首先,使用BERT(Bidirectional Encoder Representations from Transformers)预训练模型提取文本特征,并使用双向长短期记忆(Bi-LSTM)网络对预处理后的音频和视频特征进行进一步处理;其次,通过基于文本的交叉注意力机制,将文本信息融入情感相关的非语言表示中,以学习面向文本的成对跨模态映射,从而获得有效的统一多模态表示;最后,使用融合特征进行情感分析。实验结果表明,与最优的基线模型——文本增强Transformer融合网络(TETFN)相比,MSAM-CTE在数据集CMU-MOSI(Carnegie Mellon University Multimodal Opinion Sentiment Intensity)上的平均绝对误差(MAE)和皮尔逊相关系数(Corr)分别降低了2.6%和提高了0.1%;在数据集CMU-MOSEI(Carnegie Mellon University Multimodal Opinion Sentiment and Emotion Intensity)上的两个指标分别降低了3.8%和提高了1.7%,验证了MSAM-CTE在情感分析中的有效性。展开更多
针对复杂工况下矿井开采设备齿轮减速器故障预测精度不高、实时性不强的问题,提出了一种基于并行多尺度特征融合的矿井开采设备齿轮减速器故障预测模型。首先,利用卷积神经网络Vgg-16提取齿轮减速器故障数据的空间特征;然后,利用双向长...针对复杂工况下矿井开采设备齿轮减速器故障预测精度不高、实时性不强的问题,提出了一种基于并行多尺度特征融合的矿井开采设备齿轮减速器故障预测模型。首先,利用卷积神经网络Vgg-16提取齿轮减速器故障数据的空间特征;然后,利用双向长短时记忆神经网络(Bi-directional Long Short-Term Memory,Bi-LSTM)提取齿轮减速器故障数据的时序特征,并借助交叉融合注意力实现井下开采设备齿轮减速器故障数据空间特征和时序特征的深度融合,增强故障特征表达的可靠性和鲁棒性;最后,利用Softmax函数实现待测齿轮减速器故障的实时预测。通过在宁夏某矿井采集的多工况条件下的开采设备齿轮减速器故障数据集上进行测试,结果表明:所提模型在单一工况场景下可以实现94.38%的准确率、94.25%的精准率、94.16%的召回率和95.08%的F_(1)值,在多工况场景下可以实现92.73%的准确率、91.86%的精准率、91.04%的召回率和92.39%的F_(1)值,综合性能优于经典的齿轮故障预测模型。展开更多
基金Supported by the National Natural Science Foundation of China(62201171).
文摘Wigner-Ville distribution(WVD)is widely used in the field of signal processing due to its excellent time-frequency(TF)concentration.However,WVD is severely limited by the cross-term when working with multicomponent signals.In this paper,we analyze the property differences between auto-term and cross-term in the one-dimensional sequence and the two-dimensional plane and approximate entropy and Rényi entropy are employed to describe them,respectively.Based on this information,we propose a new method to achieve adaptive cross-term removal by combining seeded region growing.Compared to other methods,the new method can achieve cross-term removal without decreasing the TF concentration of the auto-term.Simulation and experimental data processing results show that the method is adaptive and is not constrained by the type or distribution of signals.And it performs well in low signal-to-noise ratio environments.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 60172026)the Basic Research Foundation of Tsinghua University (Grant No. JC2001028) and the Scientific Innovation Foundation of Ph. D. Candidates of Tsinghua Uni
文摘Wigner-Ville distribution (WVD) is recognized as being a powerful tool and a nucleus in time-frequency representation (TFR) which gives an excellent time-frequency concentration, and more importantly, has many desirable properties. A major shortcoming of WVD is the inherent cross-term (CT) interference. Although solutions to this problem from the bulk of contributions to the literature concerning TFR are currently available, none has been able to completely eliminate the CT’s in WVD. It is therefore a common belief that if there exists an auxiliary time-frequency distribution (TFD) which has the same auto-terms (AT’s) as that in WVD, but has CT’s with the opposite sign, then, by adding the auxiliary TFD to WVD, an ideal TFD, which preserves the concentration of WVD while annihilating the CT’s, is readily obtained. However, we prove that the auxiliary TFD does not exist. Moreover, it is found that in general, CT free joint distributions with their concentrations close to that of WVD do not exist either.
文摘近年来,利用文本、视觉和音频数据分析视频中说话者情感的多模态情感分析(MSA)引起了广泛关注。然而,不同模态在情感分析中的贡献大不相同。通常,文本中包含的信息更加直观,因此寻求一种用于增强文本在情感分析中作用的策略显得尤为重要。针对这一问题,提出一种跨模态文本信息增强的多模态情感分析模型(MSAMCTE)。首先,使用BERT(Bidirectional Encoder Representations from Transformers)预训练模型提取文本特征,并使用双向长短期记忆(Bi-LSTM)网络对预处理后的音频和视频特征进行进一步处理;其次,通过基于文本的交叉注意力机制,将文本信息融入情感相关的非语言表示中,以学习面向文本的成对跨模态映射,从而获得有效的统一多模态表示;最后,使用融合特征进行情感分析。实验结果表明,与最优的基线模型——文本增强Transformer融合网络(TETFN)相比,MSAM-CTE在数据集CMU-MOSI(Carnegie Mellon University Multimodal Opinion Sentiment Intensity)上的平均绝对误差(MAE)和皮尔逊相关系数(Corr)分别降低了2.6%和提高了0.1%;在数据集CMU-MOSEI(Carnegie Mellon University Multimodal Opinion Sentiment and Emotion Intensity)上的两个指标分别降低了3.8%和提高了1.7%,验证了MSAM-CTE在情感分析中的有效性。
文摘针对复杂工况下矿井开采设备齿轮减速器故障预测精度不高、实时性不强的问题,提出了一种基于并行多尺度特征融合的矿井开采设备齿轮减速器故障预测模型。首先,利用卷积神经网络Vgg-16提取齿轮减速器故障数据的空间特征;然后,利用双向长短时记忆神经网络(Bi-directional Long Short-Term Memory,Bi-LSTM)提取齿轮减速器故障数据的时序特征,并借助交叉融合注意力实现井下开采设备齿轮减速器故障数据空间特征和时序特征的深度融合,增强故障特征表达的可靠性和鲁棒性;最后,利用Softmax函数实现待测齿轮减速器故障的实时预测。通过在宁夏某矿井采集的多工况条件下的开采设备齿轮减速器故障数据集上进行测试,结果表明:所提模型在单一工况场景下可以实现94.38%的准确率、94.25%的精准率、94.16%的召回率和95.08%的F_(1)值,在多工况场景下可以实现92.73%的准确率、91.86%的精准率、91.04%的召回率和92.39%的F_(1)值,综合性能优于经典的齿轮故障预测模型。
