{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,30]],"date-time":"2025-12-30T08:47:33Z","timestamp":1767084453065,"version":"build-2065373602"},"reference-count":21,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2019,1,31]],"date-time":"2019-01-31T00:00:00Z","timestamp":1548892800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003695","name":"Korea Institute of Industrial Technology","doi-asserted-by":"publisher","award":["JA-18-0002"],"award-info":[{"award-number":["JA-18-0002"]}],"id":[{"id":"10.13039\/501100003695","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Hypertension is a well-known chronic disease that causes complications such as cardiovascular diseases or stroke, and thus needs to be continuously managed by using a simple system for measuring blood pressure. The existing method for measuring blood pressure uses a wrapping cuff, which makes measuring difficult for patients. To address this problem, cuffless blood pressure measurement methods that detect the peak pressure via signals measured using photoplethysmogram (PPG) and electrocardiogram (ECG) sensors and use it to calculate the pulse transit time (PTT) or pulse wave velocity (PWV) have been studied. However, a drawback of these methods is that a user must be able to recognize and establish contact with the sensor. Furthermore, the peak of the PPG or ECG cannot be detected if the signal quality drops, leading to a decrease in accuracy. In this study, a chair-type system that can monitor blood pressure using polyvinylidene fluoride (PVDF) films in a nonintrusive manner to users was developed. The proposed method also uses instantaneous phase difference (IPD) instead of PTT as the feature value for estimating blood pressure. Experiments were conducted using a blood pressure estimation model created via an artificial neural network (ANN), which showed that IPD could estimate more accurate readings of blood pressure compared to PTT, thus demonstrating the possibility of a nonintrusive blood pressure monitoring system.<\/jats:p>","DOI":"10.3390\/s19030595","type":"journal-article","created":{"date-parts":[[2019,2,1]],"date-time":"2019-02-01T03:08:05Z","timestamp":1548990485000},"page":"595","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["A Chair-Based Unconstrained\/Nonintrusive Cuffless Blood Pressure Monitoring System Using a Two-Channel Ballistocardiogram"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3761-8627","authenticated-orcid":false,"given":"Kwang Jin","family":"Lee","sequence":"first","affiliation":[{"name":"Deepmedi Research Institute of Technology, Deepmedi Inc., Seoul 06232, Korea"}]},{"given":"Jongryun","family":"Roh","sequence":"additional","affiliation":[{"name":"Human Convergence Technology Group, Korea Institute of Industrial Technology (KITECH), 143 Hanggaulro, Ansan 15588, Korea"}]},{"given":"Dongrae","family":"Cho","sequence":"additional","affiliation":[{"name":"Deepmedi Research Institute of Technology, Deepmedi Inc., Seoul 06232, Korea"}]},{"given":"Joonho","family":"Hyeong","sequence":"additional","affiliation":[{"name":"Human Convergence Technology Group, Korea Institute of Industrial Technology (KITECH), 143 Hanggaulro, Ansan 15588, Korea"}]},{"given":"Sayup","family":"Kim","sequence":"additional","affiliation":[{"name":"Human Convergence Technology Group, Korea Institute of Industrial Technology (KITECH), 143 Hanggaulro, Ansan 15588, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2019,1,31]]},"reference":[{"key":"ref_1","unstructured":"World Health Organization (2015). World Health Statistic 2015, World Health Organization."},{"key":"ref_2","unstructured":"World Health Organization (2014). A Global Brief on Hypertension, Silent Killer, Global Public Health Crisis, World Health Organization."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1016\/j.irbm.2014.07.002","article-title":"A review of methods for non-invasive and continuous blood pressure monitoring: Pulse transit time method is promising","volume":"35","author":"Peter","year":"2014","journal-title":"IRBM"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"608","DOI":"10.1109\/TBME.2011.2180019","article-title":"Electrocardiogram-assisted blood pressure estimation","volume":"59","author":"Ahmad","year":"2012","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1879","DOI":"10.1109\/TBME.2015.2441951","article-title":"Toward ubiquitous blood pressure monitoring via pulse transit time: Theory and practices","volume":"62","author":"Mukkamala","year":"2015","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Poon, C., and Zhang, Y. (2006, January 17\u201318). Cuff-less and noninvasive measurements of arterial blood pressure by pulse transit time. Proceedings of the 27th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Shanghai, China.","DOI":"10.1109\/IEMBS.2005.1615827"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Kumar, N., Agrawal, A., and Deb, S. (2014, January 24\u201327). Cuffless BP measurement using a correlation study of pulse transient time and heart rate. Proceedings of the International Conference on Advances in Computing, Communications and Informatics (ICACCI), New Delhi, India.","DOI":"10.1109\/ICACCI.2014.6968642"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"11554","DOI":"10.1038\/s41598-017-11507-3","article-title":"Pulse Transit Time Based Continuous Cuffless Blood Pressure Estimation: A New Extension and A Comprehensive Evaluation","volume":"7","author":"Ding","year":"2107","journal-title":"Sci. Rep."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"859","DOI":"10.1109\/TBME.2016.2580904","article-title":"Cuff-less Blood Pressure Estimation Algorithms for Contentious Health-care Monitoring","volume":"64","author":"Kachuee","year":"2017","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Su, P., Ding, X., Zhang, Y., Liu, J., Miao, F., and Zhao, N. (2018, January 4\u20137). Long-term blood pressure prediction with deep recurrent neural networks. Proceedings of the IEEE EMBS International Conference on Biomedical & Health Informatics (BHI), Las Vegas, NV, USA.","DOI":"10.1109\/BHI.2018.8333434"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"838","DOI":"10.1109\/TIM.2013.2287118","article-title":"Novel Methods for Noncontact Heart Rate Measurement: A Feasibility Study","volume":"63","author":"Kranjec","year":"2014","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"3224","DOI":"10.3390\/s150203224","article-title":"A Pressure Sensing System for Heart Rate Monitoring with Polymer-Based Pressure Sensors and an Anti-Interference Post Processing Circuit","volume":"15","author":"Shu","year":"2015","journal-title":"Sensors"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1016\/j.compind.2017.05.005","article-title":"Low-power, noninvasive measurement system for wearable ballistocardiography in sitting and standing positions","volume":"91","author":"Liu","year":"2017","journal-title":"Comput. Ind."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2657","DOI":"10.1109\/TBME.2015.2440291","article-title":"Ballistocardiogram as Proximal Timing Reference for Pulse Transit Time Measurement: Potential for Cuffless Blood Pressure Monitoring","volume":"62","author":"Kim","year":"2014","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1194","DOI":"10.1109\/JBHI.2016.2614962","article-title":"A Chair-based Unobtrusive Cuffless Blood Pressure Monitoring System Based on Pulse Arrival Time","volume":"21","author":"Tang","year":"2017","journal-title":"IEEE J. Biomed. Health Inform."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Sadek, I. (arXiv, 2018). Ballistocardiogram Signal Processing: A Literature Review, arXiv.","DOI":"10.1007\/s13755-019-0071-7"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"903","DOI":"10.1098\/rspa.1998.0193","article-title":"The empirical mode decomposition and the Hilbert spectrum for nonlinear and non-stationary time series analysis","volume":"454","author":"Huang","year":"1998","journal-title":"Proc. R. Soc. Lond. A Math. Phys. Eng. Sci."},{"key":"ref_18","first-page":"4218","article-title":"Techniques for estimating blood pressure variation using video images","volume":"2015","author":"Sugita","year":"2015","journal-title":"Conf. Proc. IEEE Eng. Med. Biol. Soc."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"82","DOI":"10.1016\/j.bspc.2016.10.014","article-title":"Estimation of blood pressure variability during orthostatic test using instantaneous photoplethysmogram frequency and pulse arrival time","volume":"32","author":"Rapalis","year":"2017","journal-title":"Biomed. Signal Process. Control"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1145","DOI":"10.1016\/j.compbiomed.2009.10.006","article-title":"Adaptive threshold method for the peak detection of photoplethysmographic waveform","volume":"39","author":"Shin","year":"2009","journal-title":"Comput. Biol. Med."},{"key":"ref_21","unstructured":"Association for the Advancement of the Medical Instrumentation (2002). American National Standard for Electronic or Automated Sphygmomanometers, AAMI. ANSI\/AAMI SP 10 2201."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/3\/595\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:29:51Z","timestamp":1760185791000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/3\/595"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,1,31]]},"references-count":21,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2019,2]]}},"alternative-id":["s19030595"],"URL":"https:\/\/doi.org\/10.3390\/s19030595","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2019,1,31]]}}}