{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,3]],"date-time":"2026-01-03T06:48:01Z","timestamp":1767422881918,"version":"build-2065373602"},"reference-count":32,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2020,12,12]],"date-time":"2020-12-12T00:00:00Z","timestamp":1607731200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education","award":["No. NRF-2017R1A6A1A03015496"],"award-info":[{"award-number":["No. NRF-2017R1A6A1A03015496"]}]},{"name":"This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT)","award":["No. NRF-2018R1A2B6001984"],"award-info":[{"award-number":["No. NRF-2018R1A2B6001984"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Although biometrics systems using an electrocardiogram (ECG) have been actively researched, there is a characteristic that the morphological features of the ECG signal are measured differently depending on the measurement environment. In general, post-exercise ECG is not matched with the morphological features of the pre-exercise ECG because of the temporary tachycardia. This can degrade the user recognition performance. Although normalization studies have been conducted to match the post- and pre-exercise ECG, limitations related to the distortion of the P wave, QRS complexes, and T wave, which are morphological features, often arise. In this paper, we propose a method for matching pre- and post-exercise ECG cycles based on time and frequency fusion normalization in consideration of morphological features and classifying users with high performance by an optimized system. One cycle of post-exercise ECG is expanded by linear interpolation and filtered with an optimized frequency through the fusion normalization method. The fusion normalization method aims to match one post-exercise ECG cycle to one pre-exercise ECG cycle. The experimental results show that the average similarity between the pre- and post-exercise states improves by 25.6% after normalization, for 30 ECG cycles. Additionally, the normalization algorithm improves the maximum user recognition performance from 96.4 to 98%.<\/jats:p>","DOI":"10.3390\/s20247130","type":"journal-article","created":{"date-parts":[[2020,12,13]],"date-time":"2020-12-13T23:39:36Z","timestamp":1607902776000},"page":"7130","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":22,"title":["Recognition System Using Fusion Normalization Based on Morphological Features of Post-Exercise ECG for Intelligent Biometrics"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8435-6068","authenticated-orcid":false,"given":"Gyu Ho","family":"Choi","sequence":"first","affiliation":[{"name":"IT Research Institute, Chosun University, Gwangju 61452, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4604-1735","authenticated-orcid":false,"given":"Hoon","family":"Ko","sequence":"additional","affiliation":[{"name":"IT Research Institute, Chosun University, Gwangju 61452, Korea"}]},{"given":"Witold","family":"Pedrycz","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Alberta University, Edmonton, AB T6G 2R3, Canada"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7359-2068","authenticated-orcid":false,"given":"Amit Kumar","family":"Singh","sequence":"additional","affiliation":[{"name":"Department of Computer Science Engineering, National Institute of Technology Patna, Patna 800005, India"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0960-5706","authenticated-orcid":false,"given":"Sung Bum","family":"Pan","sequence":"additional","affiliation":[{"name":"IT Research Institute, Chosun University, Gwangju 61452, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2020,12,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Choi, G.H., Ko, H., Pedrycz, W., and Pan, S.B. 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