REFERENCES
1. Mukkamala R, Hahn JO, Inan OT, et al. Toward ubiquitous blood pressure monitoring via pulse transit time: theory and practice. IEEE Trans Biomed Eng 2015;62:1879-901.
2. Seeberg TM, Orr JG, Opsahl H, et al. A novel method for continuous, noninvasive, cuff-less measurement of blood pressure: evaluation in patients with nonalcoholic fatty liver disease. IEEE Trans Biomed Eng 2017;64:1469-78.
3. Kachuee M, Kiani MM, Mohammadzade H, Shabany M. Cuffless blood pressure estimation algorithms for continuous health-care monitoring. IEEE Trans Biomed Eng 2017;64:859-69.
4. Tamura T. Cuffless blood pressure monitors: principles, standards and approval for medical use. IEICE Trans Commun 2021;E104.B:580-6.
5. Castaneda D, Esparza A, Ghamari M, Soltanpur C, Nazeran H. A review on wearable photoplethysmography sensors and their potential future applications in health care. Int J Biosens Bioelectron 2018;4:195-202.
6. Hartmann V, Liu H, Chen F, Qiu Q, Hughes S, Zheng D. Quantitative comparison of photoplethysmographic waveform characteristics: effect of measurement site. Front Physiol 2019;10:198.
7. Teng XF, Zhang YT. Theoretical study on the effect of sensor contact force on pulse transit time. IEEE Trans Biomed Eng 2007;54:1490-8.
8. Grabovskis A, Marcinkevics Z, Rubins U, Kviesis-Kipge E. Effect of probe contact pressure on the photoplethysmographic assessment of conduit artery stiffness. J Biomed Opt 2013;18:27004.
9. Shimazaki T, Kuwahara Y, Kimoto M, Hara S, Yomo H. Effect of position and fastening belt pressure on the accuracy of PPG-based heart rate sensor. Annu Int Conf IEEE Eng Med Biol Soc 2018;2018:4323-6.
10. May JM, Mejía-Mejía E, Nomoni M, Budidha K, Choi C, Kyriacou PA. Effects of contact pressure in reflectance photoplethysmography in an in vitro tissue-vessel phantom. Sensors 2021;21:8421.
11. Pi I, Pi I, Wu W. External factors that affect the photoplethysmography waveforms. SN Appl Sci 2022;4:21.
12. Chandrasekhar A, Yavarimanesh M, Natarajan K, Hahn JO, Mukkamala R. PPG sensor contact pressure should be taken into account for cuff-less blood pressure measurement. IEEE Trans Biomed Eng 2020;67:3134-40.
13. Liu ZJ, Xiang T, Ji N, Zhang YT. Some perspectives of continuous arterial blood pressure measurements: from kymograph to tonoarteriographic imaging. Conn Health Telemed 2023;2:200008.
14. Liu ZJ, Xiang T, Ji N, Zhang YT. Optical sensor array-based multi-channel wearable tonoarteriogram (TAG) imaging system. 45th Annual International Conference of the IEEE Engineering in Medicine and Biology Society; 2023.
15. PulseSensor. Available from: https://pulsesensor.com/pages/processing-visualization [Last accessed on 2 Feb 2024].
16. Specification for Ceramic Piezoelectric Sensor. Available from: https://www.indiamart.com/proddetail/piezo-buzzer-20mm-buzzp-2853058569833.html [Last accessed on 2 Feb 2024].
17. Sim JK, Ahn BY, Doh I. A contact-force regulated photoplethysmography (PPG) platform. AIP Advances 2018;8:045210.
18. Zhang Y, Song S, Vullings R, et al. Motion artifact reduction for wrist-worn photoplethysmograph sensors based on different wavelengths. Sensors 2019;19:673.
19. Rafolt D, Gallasch E. Influence of contact forces on wrist photoplethysmography--prestudy for a wearable patient monitor. Biomed Tech 2004;49:22-6.
