{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,15]],"date-time":"2025-10-15T10:19:40Z","timestamp":1760523580765,"version":"build-2065373602"},"reference-count":19,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2018,1,15]],"date-time":"2018-01-15T00:00:00Z","timestamp":1515974400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Continuous cardiac monitoring has been developed to evaluate cardiac activity outside of clinical environments due to the advancement of novel instruments. Seismocardiography (SCG) is one of the vital components that could develop such a monitoring system. Although SCG has been presented with a lower accuracy, this novel cardiac indicator has been steadily proposed over traditional methods such as electrocardiography (ECG). Thus, it is necessary to develop an enhanced method by combining the significant cardiac indicators. In this study, the six-axis signals of accelerometer and gyroscope were measured and integrated by the L2 normalization and multi-dimensional kineticardiography (MKCG) approaches, respectively. The waveforms of accelerometer and gyroscope were standardized and combined via ensemble averaging, and the heart rate was calculated from the dominant frequency. Thirty participants (15 females) were asked to stand or sit in relaxed and aroused conditions. Their SCG was measured during the task. As a result, proposed method showed higher accuracy than traditional SCG methods in all measurement conditions. The three main contributions are as follows: (1) the ensemble averaging enhanced heart rate estimation with the benefits of the six-axis signals; (2) the proposed method was compared with the previous SCG method that employs fewer-axis; and (3) the method was tested in various measurement conditions for a more practical application.<\/jats:p>","DOI":"10.3390\/s18010238","type":"journal-article","created":{"date-parts":[[2018,1,15]],"date-time":"2018-01-15T12:30:36Z","timestamp":1516019436000},"page":"238","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":38,"title":["An Enhanced Method to Estimate Heart Rate from Seismocardiography via Ensemble Averaging of Body Movements at Six Degrees of Freedom"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5173-726X","authenticated-orcid":false,"given":"Hyunwoo","family":"Lee","sequence":"first","affiliation":[{"name":"Department of Emotion Engineering, University of Sangmyung, Seoul 03016, Korea"}]},{"given":"Hana","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Emotion Engineering, University of Sangmyung, Seoul 03016, Korea"}]},{"given":"Mincheol","family":"Whang","sequence":"additional","affiliation":[{"name":"Department of Intelligence Informatics Engineering, University of Sangmyung, Seoul 03016, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2018,1,15]]},"reference":[{"key":"ref_1","first-page":"55","article-title":"Seismocardiography\u2014A New Method in the Study of Functional Conditions of the Heart","volume":"33","author":"Bozhenko","year":"1961","journal-title":"Ter. Arkhiv"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"991","DOI":"10.1378\/chest.100.4.991","article-title":"Seismocardiography for Monitoring Changes in Left Ventricular Function during Ischemia","volume":"100","author":"Salerno","year":"1991","journal-title":"Chest"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1016\/j.autneu.2013.04.005","article-title":"Wearable Seismocardiography: Towards a Beat-by-Beat Assessment of Cardiac Mechanics in Ambulant Subjects","volume":"178","author":"Vaini","year":"2013","journal-title":"Auton. Neurosci."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Migeotte, P.F., De Ridder, S., Tank, J., Pattyn, N., Funtova, I., Baevsky, R., Neyt, X., and Prisk, G.K. (2012). Three Dimensional Ballisto-and Seismo-Cardiography: HIJ Wave Amplitudes are Poorly Correlated to Maximal Systolic Force Vector. IEEE Eng. Med. Biol. Soc.","DOI":"10.1109\/EMBC.2012.6347127"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Pandia, K., Ravindran, S., Cole, R., and Kovacs, G. (2010). Laurent Giovangrandi. Motion Artifact Cancellation to Obtain Heart Sounds from a Single Chest-Worn Accelerometer. IEEE Acoust. Speech Signal Process.","DOI":"10.1109\/ICASSP.2010.5495553"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"435","DOI":"10.1109\/JBHI.2015.2391437","article-title":"Beat-by-Beat Quantification of Cardiac Cycle Events Detected from Three-Dimensional Precordial Acceleration Signals","volume":"20","author":"Paukkunen","year":"2016","journal-title":"IEEE J. Biomed. Health Inform."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Tadi, M.J., Lehtonen, E., Pankaala, M., Saraste, A., Vasankari, T., Teras, M., and Koivisto, T. (2016). Gyrocardiography: A New Non-Invasive Approach in the Study of Mechanical Motions of the Heart. Concept, Method and Initial Observations. IEEE Eng. Med. Biol. Soc.","DOI":"10.1109\/EMBC.2016.7591126"},{"key":"ref_8","unstructured":"Migeotte, P.F., Mucci, V., Deli\u00e8re, Q., Lejeune, L., and van de Borne, P. (April, January 31). Multi-dimensional Kineticardiography a New Approach for Wearable Cardiac Monitoring through Body Acceleration Recordings. Proceedings of the XIV Mediterranean Conference on Medical and Biological Engineering and Computing, Paphos, Cyprus."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2129","DOI":"10.1109\/JSEN.2017.2663420","article-title":"Utilizing Gyroscopes towards the Automatic Annotation of Seismocardiograms","volume":"17","author":"Yang","year":"2017","journal-title":"IEEE Sens. J."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Jia, W., Li, Y., Bai, Y., Mao, Z.-H., Sun, M., and Zhao, Q. (2015, January 14\u201317). Estimation of Heart Rate from a Chest-Worn Inertial Measurement Unit. Proceedings of the IEEE International Symposium on Bioelectronics and Bioinformatics (ISBB), Beijing, China.","DOI":"10.1109\/ISBB.2015.7344945"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Hernandez, J., Li, Y., Rehg, J.M., and Picard, R.W. (2014). Bioglass: Physiological Parameter Estimation using a Head-Mounted Wearable Device. IEEE Wirel. Mob. Commun. Healthc.","DOI":"10.4108\/icst.mobihealth.2014.257219"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1152\/ajplegacy.1939.127.1.1","article-title":"Studies on the Estimation of Cardiac Output in Man, and of Abnormalities in Cardiac Function, from the heart\u2019s Recoil and the blood\u2019s Impacts; the Ballistocardiogram","volume":"127","author":"Starr","year":"1939","journal-title":"Am. J. Physiol. Leg. Content"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"175","DOI":"10.3758\/BF03193146","article-title":"G*Power 3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences","volume":"39","author":"Faul","year":"2007","journal-title":"Behav. Res. Methods"},{"key":"ref_14","first-page":"1049","article-title":"Cubic Spline Interpolation","volume":"45","author":"McKinley","year":"1998","journal-title":"Coll. Redw."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1627","DOI":"10.1021\/ac60214a047","article-title":"Smoothing and Differentiation of Data by Simplified Least Squares Procedures","volume":"36","author":"Savitzky","year":"1964","journal-title":"Anal. Chem."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1414","DOI":"10.1109\/JBHI.2014.2361732","article-title":"Ballistocardiography and Seismocardiography: A Review of Recent Advances","volume":"19","author":"Inan","year":"2015","journal-title":"IEEE J. Biomed. Health Inform."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Pan, J., and Tompkins, W.J. (1985). A Real-Time QRS Detection Algorithm. IEEE Trans. Biomed. Eng., 230\u2013236.","DOI":"10.1109\/TBME.1985.325532"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Castiglioni, P., Faini, A., Parati, G., and Di Rienzo, M. (2007). Wearable Seismocardiography. IEEE Eng. Med. Biol. Soc.","DOI":"10.1109\/IEMBS.2007.4353199"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1109\/TBCAS.2010.2052616","article-title":"Mechanically Flexible Wireless Multisensor Platform for Human Physical Activity and Vitals Monitoring","volume":"4","author":"Chuo","year":"2010","journal-title":"IEEE Trans. Biomed. Circuits Syst."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/1\/238\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T14:51:19Z","timestamp":1760194279000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/1\/238"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,1,15]]},"references-count":19,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2018,1]]}},"alternative-id":["s18010238"],"URL":"https:\/\/doi.org\/10.3390\/s18010238","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2018,1,15]]}}}