{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T18:00:24Z","timestamp":1777572024596,"version":"3.51.4"},"reference-count":44,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2019,10,2]],"date-time":"2019-10-02T00:00:00Z","timestamp":1569974400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/2.zoppoz.workers.dev:443\/https\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["51708315"],"award-info":[{"award-number":["51708315"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Provincial Key Research and Development Program of Shandong","award":["2018GSF120017"],"award-info":[{"award-number":["2018GSF120017"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper proposes a methodology to process and interpret the complex signals acquired from the health monitoring of civil structures via scale-space empirical wavelet transform (EWT). The FREEVIB method, a widely used instantaneous modal parameters identification method, determines the structural characteristics from the individual components separated by EWT first. The scale-space EWT turns the detecting of the frequency boundaries into the scale-space representation of the Fourier spectrum. As well, to find meaningful modes becomes a clustering problem on the length of minima scale-space curves. The Otsu\u2019s algorithm is employed to determine the threshold for the clustering analysis. To retain the time-varying features, the EWT-extracted mono-components are analyzed by the FREEVIB method to obtain the instantaneous modal parameters and the linearity characteristics of the structures. Both simulated and real SHM signals from civil structures are used to validate the effectiveness of the present method. The results demonstrate that the proposed methodology is capable of separating the signal components, even those closely spaced ones in frequency domain, with high accuracy, and extracting the structural features reliably.<\/jats:p>","DOI":"10.3390\/s19194280","type":"journal-article","created":{"date-parts":[[2019,10,3]],"date-time":"2019-10-03T03:41:27Z","timestamp":1570074087000},"page":"4280","update-policy":"https:\/\/2.zoppoz.workers.dev:443\/https\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Mono-Component Feature Extraction for Condition Assessment in Civil Structures Using Empirical Wavelet Transform"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/2.zoppoz.workers.dev:443\/https\/orcid.org\/0000-0001-8101-3636","authenticated-orcid":false,"given":"Yun-Xia","family":"Xia","sequence":"first","affiliation":[{"name":"School of Civil Engineering, Qingdao University of Technology, Qingdao 266033, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/2.zoppoz.workers.dev:443\/https\/orcid.org\/0000-0002-2347-647X","authenticated-orcid":false,"given":"Yun-Lai","family":"Zhou","sequence":"additional","affiliation":[{"name":"Faculty of Engineering, Universidade Lus\u00f3fona, 1749-024 Lisbon, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,10,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"235","DOI":"10.1109\/TASSP.1977.1162950","article-title":"Short term spectral analysis, synthesis, and modification by discrete Fourier transform","volume":"25","author":"Allen","year":"1977","journal-title":"IEEE Trans. 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