{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T00:39:39Z","timestamp":1778632779448,"version":"3.51.4"},"reference-count":31,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2022,9,19]],"date-time":"2022-09-19T00:00:00Z","timestamp":1663545600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Institute of Engineering Research at Seoul National University","award":["2021R1F1A1059914"],"award-info":[{"award-number":["2021R1F1A1059914"]}]},{"name":"Ministry of Education, Science and Technology","award":["2021R1F1A1059914"],"award-info":[{"award-number":["2021R1F1A1059914"]}]},{"name":"Basic Science Research Program of the National Research Foundation of Korea","award":["2021R1F1A1059914"],"award-info":[{"award-number":["2021R1F1A1059914"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>As the demand for ocean exploration increases, studies are being actively conducted on autonomous underwater vehicles (AUVs) that can efficiently perform various missions. To successfully perform long-term, wide-ranging missions, it is necessary to apply fault diagnosis technology to AUVs. In this study, a system that can monitor the health of in situ AUV thrusters using a convolutional neural network (CNN) was developed. As input data, an acoustic signal that comprehensively contains the mechanical and hydrodynamic information of the AUV thruster was adopted. The acoustic signal was pre-processed into two-dimensional data through continuous wavelet transform. The neural network was trained with three different pre-processing methods and the accuracy was compared. The decibel scale was more effective than the linear scale, and the normalized decibel scale was more effective than the decibel scale. Through tests on off-training conditions that deviate from the neural network learning condition, the developed system properly recognized the distribution characteristics of noise sources even when the operating speed and the thruster rotation speed changed, and correctly diagnosed the state of the thruster. These results showed that the acoustic signal-based CNN can be effectively used for monitoring the health of the AUV\u2019s thrusters.<\/jats:p>","DOI":"10.3390\/s22187073","type":"journal-article","created":{"date-parts":[[2022,9,20]],"date-time":"2022-09-20T04:28:55Z","timestamp":1663648135000},"page":"7073","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":22,"title":["Enhanced Convolutional Neural Network for In Situ AUV Thruster Health Monitoring Using Acoustic Signals"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2737-1795","authenticated-orcid":false,"given":"Sang-Jae","family":"Yeo","sequence":"first","affiliation":[{"name":"Department of Naval Architecture and Ocean Engineering, Seoul National University, Seoul 08826, Korea"},{"name":"Institute of Engineering Research, Seoul National University, Seoul 08826, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Woen-Sug","family":"Choi","sequence":"additional","affiliation":[{"name":"Department of Ocean Engineering, Korea Maritime and Ocean University, Busan 49112, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Suk-Yoon","family":"Hong","sequence":"additional","affiliation":[{"name":"Department of Naval Architecture and Ocean Engineering, Seoul National University, Seoul 08826, Korea"},{"name":"Institute of Engineering Research, Seoul National University, Seoul 08826, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jee-Hun","family":"Song","sequence":"additional","affiliation":[{"name":"Department of Naval Architecture and Ocean Engineering, Chonnam National University, Yeosu 59626, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,9,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3259","DOI":"10.1038\/s41467-021-23168-y","article-title":"Financing a sustainable ocean economy","volume":"12","author":"Sumaila","year":"2021","journal-title":"Nat. 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