{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,4]],"date-time":"2026-03-04T17:35:57Z","timestamp":1772645757296,"version":"3.50.1"},"reference-count":94,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2021,5,3]],"date-time":"2021-05-03T00:00:00Z","timestamp":1620000000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004663","name":"Ministry of Science and Technology, Taiwan","doi-asserted-by":"publisher","award":["MOST 109-2218-E-011-014"],"award-info":[{"award-number":["MOST 109-2218-E-011-014"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>During the pandemic of coronavirus disease-2019 (COVID-19), medical practitioners need non-contact devices to reduce the risk of spreading the virus. People with COVID-19 usually experience fever and have difficulty breathing. Unsupervised care to patients with respiratory problems will be the main reason for the rising death rate. Periodic linearly increasing frequency chirp, known as frequency-modulated continuous wave (FMCW), is one of the radar technologies with a low-power operation and high-resolution detection which can detect any tiny movement. In this study, we use FMCW to develop a non-contact medical device that monitors and classifies the breathing pattern in real time. Patients with a breathing disorder have an unusual breathing characteristic that cannot be represented using the breathing rate. Thus, we created an Xtreme Gradient Boosting (XGBoost) classification model and adopted Mel-frequency cepstral coefficient (MFCC) feature extraction to classify the breathing pattern behavior. XGBoost is an ensemble machine-learning technique with a fast execution time and good scalability for predictions. In this study, MFCC feature extraction assists machine learning in extracting the features of the breathing signal. Based on the results, the system obtained an acceptable accuracy. Thus, our proposed system could potentially be used to detect and monitor the presence of respiratory problems in patients with COVID-19, asthma, etc.<\/jats:p>","DOI":"10.3390\/s21093172","type":"journal-article","created":{"date-parts":[[2021,5,5]],"date-time":"2021-05-05T22:51:42Z","timestamp":1620255102000},"page":"3172","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":56,"title":["Non-Contact Monitoring and Classification of Breathing Pattern for the Supervision of People Infected by COVID-19"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2839-8172","authenticated-orcid":false,"given":"Ariana Tulus","family":"Purnomo","sequence":"first","affiliation":[{"name":"Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1980-0609","authenticated-orcid":false,"given":"Ding-Bing","family":"Lin","sequence":"additional","affiliation":[{"name":"Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0106-0609","authenticated-orcid":false,"given":"Tjahjo","family":"Adiprabowo","sequence":"additional","affiliation":[{"name":"Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6209-3981","authenticated-orcid":false,"given":"Willy Fitra","family":"Hendria","sequence":"additional","affiliation":[{"name":"Department of Intelligent Mechatronics Engineering, Sejong University, Seoul 05006, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2021,5,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"785","DOI":"10.1002\/bjs.11627","article-title":"COVID-19 pandemic: Perspectives on an unfolding crisis","volume":"107","author":"Spinelli","year":"2020","journal-title":"Br. 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