Output-only modal identification based on the variational mode decomposition (VMD) framework

2021 ◽  
pp. 116668
Author(s):  
Shuaishuai Liu ◽  
Rui Zhao ◽  
Kaiping Yu ◽  
Bowen Zheng ◽  
Baopeng Liao
2020 ◽  
Vol 20 (11) ◽  
pp. 2050115
Author(s):  
Meng-Meng Sun ◽  
Qiu-Sheng Li ◽  
Kang Zhou ◽  
Ying-Hou He ◽  
Lun-Hai Zhi

For high-rise buildings subjected to ambient excitations such as typhoons and earthquake actions, their structural responses may include non-stationary features. Under such conditions, traditional modal identification methods may not be applicable due to the violation of the stationary assumption of the response signals. To deal with this issue, a novel modal identification method is presented in this paper based on combination of the variational mode decomposition (VMD) and direct interpolation (DI) techniques. Through numerical simulation study of a three-story frame structure, the effectiveness and accuracy of the combined VMD-DI method for modal identification of the structure are validated for the case of the structural responses containing non-stationary properties and high-level noise. Moreover, the novel method is further applied to the field measurements of acceleration responses of a 600[Formula: see text]m high skyscraper during a typhoon. The identified results verify the applicability and accuracy of the combined VMD-DI method in field measurements. This paper aims to provide an effective tool for modal identification from non-stationary structural responses of high-rise buildings.


Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1952
Author(s):  
May Phu Paing ◽  
Supan Tungjitkusolmun ◽  
Toan Huy Bui ◽  
Sarinporn Visitsattapongse ◽  
Chuchart Pintavirooj

Automated segmentation methods are critical for early detection, prompt actions, and immediate treatments in reducing disability and death risks of brain infarction. This paper aims to develop a fully automated method to segment the infarct lesions from T1-weighted brain scans. As a key novelty, the proposed method combines variational mode decomposition and deep learning-based segmentation to take advantages of both methods and provide better results. There are three main technical contributions in this paper. First, variational mode decomposition is applied as a pre-processing to discriminate the infarct lesions from unwanted non-infarct tissues. Second, overlapped patches strategy is proposed to reduce the workload of the deep-learning-based segmentation task. Finally, a three-dimensional U-Net model is developed to perform patch-wise segmentation of infarct lesions. A total of 239 brain scans from a public dataset is utilized to develop and evaluate the proposed method. Empirical results reveal that the proposed automated segmentation can provide promising performances with an average dice similarity coefficient (DSC) of 0.6684, intersection over union (IoU) of 0.5022, and average symmetric surface distance (ASSD) of 0.3932, respectively.


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