• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2022.05a
• /
• pp.660-662
• /
• 2022

Due to the prolonged aftermath of COVID-19, the number of modern people suffering from stress and mental illness is increasing. Recently, various methods of color therapy are being studied using LED lighting to improve concentration, relieve stress, manage skin, and improve sleep quality. In this paper, pulse waves are measured and heart rate variability is extracted using a PPG (Photoplethysmogram) sensor to analyze a person's mental and physical state. Using RGBLED and Arduino, we propose a mood lighting system that automatically changes colors according to changes in mental and physical conditions by producing color lighting of various wavelengths, which are mainly used to stabilize the mental state.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.44 no.4 s.316
• /
• pp.15-20
• /
• 2007

Recently the prevalence rate of diabetes in Korea has been increasing rapidly due to high growth of economy and changes in dietary lifestyle. Vascular complication is one of diabetic complications which have frequently occurred by obesity, hyperglycemia and impaired glucose metabolism. Photoplethysmogram(PPG) measured from finger and toe is very useful for evaluation of vascular aging and sclerosis level since the PPG signal represents characteristics of peripheral vascular Several researchers have reported that second derivative of the finger PPG waveform was useful to evaluate vascular compliance and developed various analysis methods for vascular compliance. However, peripheral vascular compliance study for diabetic patient was never evaluated by using second derivative of PPG. Therefore, we aimed to objectively compare and to assess normal(n=850) and diabetic(n=50) groups vascular compliance using the second derivative of PPG waveform in this study. The evaluated factors of the second derivative of PPG are 'a', 'b', 'c', 'd', 'e' and b/a rapresents vascular compliance. This study found out that when vascular compliance is decreased, the absolute value of b/a is decreased. The average vascular compliance of 50 diabetic patients with neuropathy, $-1.09{\pm}0.14$ is statistically lower than the normal group, $-0.81{\pm}0.09$ (p<0.05). In conclusion, we suggest an objective evaluation of peripheral vascular compliance for diabetic patients and prevention of vascular complication.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.29 no.3
• /
• pp.230-239
• /
• 2015

This study was performed to find a relationship between each pattern identification and vascular status using the second derivative of photoplethysmogram waveform(SDPTG) indices. We analyzed 200 subjects who participated in stroke preventive examination. We classified the subjects into four groups of pattern identifications; Fire-Heat pattern(火熱證; FH), Yin Deficiency pattern(陰虛證; YD), Qi Deficiency pattern(氣虛證; QD) and Dampness-Phlegm pattern(濕痰證; DP) that based on Korean Standard Pattern Identifications for Stroke-Ⅲ. We studied a relationship between each pattern identification and the SDPTG. The total number of the subject group was 200, whereas the groups were divided into four groups; Fire-Heat pattern group(n=49), Yin Deficiency pattern(n=57), Qi Deficiency pattern(n=45), and Dampness-Phlegm pattern(n=49). b/a ratio was related with age and systolic blood pressure, c/a ratio was associated with age, systolic blood pressure, fasting blood sugar and Total cholesterol, d/a ratio was affected with age, diastolic blood pressure, and hypertension, e/a ratio was related with age and sex and SDPTG AI was associated with age. c/a ratio and d/a ratio were significantly higher in the Fire-Heat group than in the Qi Deficiency group. SDPTG AI was significantly higher in the Qi Deficiency group than in the Fire-Heat group. The Qi Deficiency group was significantly older than the Fire-Heat group and the number of hypertension patients was significantly more in the Fire-Heat group than in the Qi Deficiency group. Through this study, we found out some significant relationships between each pattern identification group and the SDPTG indices.

• Journal of IKEEE
• /
• v.28 no.2
• /
• pp.221-227
• /
• 2024

This paper presents a smartphone-attachable vascular compliance monitoring module. The proposed sensor module measures photoplethysmogram (PPG) and reconstructs an accelerated PPG waveform. The feature points are extracted from the accelerated PPG waves, and vascular compliance is estimated using these extracted features. The module is powered via the smartphone's USB terminal and transmits the acquired waveforms along with vascular compliance values through Bluetooth. The transmitted waveforms and vascular compliance value are displayed through the smartphone application. This work proposes an assessment method for consistency of PPG instrumentation, and it was implemented in a processor of sensor module. The proposed sensor module can be easily attached to smartphone that does not support PPG instrumentation, providing simple measurment and numerical analysis of vascular compliance. To verify the performance of the implemented sensor module, we acquired vascular compliance and pulse pressure data from 29 subjects. Pulse pressure, which serves as a representative indicator of vascular compliance, was obtained using a commercial blood pressure monitor. The analysis results showed that the Pearson coefficient between vascular compliance and pulse pressure was 0.778, confirming a relatively high correlation between two metrics.

• Science of Emotion and Sensibility
• /
• v.11 no.4
• /
• pp.637-644
• /
• 2008

Human emotion has been tried to be recognized by physiological measurements in developing emotion machine enabling to understand and react to user's emotion. This study is to find the time-dependent physiological measurements and their variation characteristics for discriminating emotions according to dimensional emotion model. Ten university students were asked to watch sixteen prepared images to evoke different emotions. Their subjective emotions and autonomic nervous responses such as ECG (electrocardiogram), PPG (photoplethysmogram), GSR (Galvanic skin response), RSP (respiration), and SKT(skin temperature) were measured during experiment. And these responses were analyzed into HR(Heart Rate), Respiration Rate, GSR amplitude average, SKT amplitude average, PPG amplitude, and PTT(Pulse Transition Time). TDPs(Time dependent parameters) defined as the delay, the activation, the half recovery and the full recovery of respective physiological signal in this study have been determined and statistically compared between variations from different emotions. The significant tendencies in TDP were shown between emotions. Therefore, TDP may provide useful measurements with emotion recognition.

• Science of Emotion and Sensibility
• /
• v.20 no.3
• /
• pp.89-96
• /
• 2017

This study developed a method which recognizes emotional interactions from the social distance by a beacon wearable device. The recognized interaction was evaluated by comparing with the cardiovascular synchrony from photoplethysmogram (PPG). The interaction was recognized when social distance was maintained for a certain period of time. The cardiovascular synchrony was estimated by correlation anaysis between beat per minute (BPM) from PPG. The maintenance time was determined by Mann-Whitney U test between the cardiovascular synchrony of interaction and non-interaction groups. Fifteen groups (2 persons per a group) participated in the experiment and they were asked to wear the beacon and PPG wearable devices in daily life. Experimental results showed that the interaction groups had more higher cardiovascular synchrony than non-interaction groups and the significant interaction time was determined to be 11 seconds (p=.045). Consequently, the real-time measurement and evaluation of the social network in real space was expected to be improved.

• Journal of IKEEE
• /
• v.11 no.3
• /
• pp.108-116
• /
• 2007

This paper proposed an analyzable parameter and its analytic method to provide more accurate information than currently employed 4 channels system which uses pulse wave velocity (PWV) information of the volume pulse wave measured from 4 arterial channels for the characterization of arterial vessel. In order to verify the volume pulse waves on 4 sites were simultaneously acquired subjects aged from 12 to 81 years old. and the proposed parameters were extracted from time (UT) was then compared with blood pressure. Then, the regression analyses were done relationships among the proposed parameter and others, such as aging, pulse transit time pressure (BP). The followings are the results of linear regression analysis of the proposed parameter for total 50 normal subjects. We selected any two subjects (58 years and 27 years) and measured PPG (photoplethysmogram) and BP of before and after exercise. The coefficient of correlations between BP and UT observed was -0.928 for 50 years subject, and -0.922 for 20 years subject. For total 50 normal subjects, in case of correlation between the pulse transit time and BP, the result showed -0.170 on left side and -0.233 on right side, and the coefficient value of correlation between the pulse transit time and UT was -0.607 on left side and -0.510 on right side. UI is strongly correlated with the pulse transit time than BP. Hence, we believe that the proposed parameter is related with the index of arterial stiffness.

• Journal of Biomedical Engineering Research
• /
• v.23 no.6
• /
• pp.485-489
• /
• 2002

In this study. respiratory efforts were monitored by the change of pulse transit time (PTT) which is related with the arterial pressure PTT is the time interval between the peak of R wave in ECG and the maximal slope point of photoplethysmogram(PPG). Biosignals, ECG and finger photoplethysmogram(PPG), were converted to digital data, and PTT was evaluated in personal computer with every heart beat. Results were presented as a graph using spline interpolation. The software was implemented in C$\^$++/ as a window-based application program. PTT was periodically changed according to airflow in resting respiration. In the resting respiration, PTT was changed according to the respiratory cycle. The amplitude of PTT fluctuation was increased by deep respiration, and increased by partial airway obstruction. These results suggest that PTT is responsible to respiratory effort which could be evaluated by the pattern of PTT change. And it is expected that PTT could be applied in the monitoring of respiratory effort by noninvasive methods, and is very useful method for the evaluation of respiratory distress.

• Journal of the Korean Society of Radiology
• /
• v.5 no.1
• /
• pp.19-25
• /
• 2011

Photoplethysmogram(PPG) is the method to obtain the biomedical signal using the linear relationships between the blood volume for changing the cardiac contraction and relaxation and the amount of light for absorbing the hemoglobin in the blood. In this paper, we proposed the analyzed results which show the heart rate variability and the distribution of heart rate for before and after using PPG. Moreover, this paper designed and implemented the system based on personal computer to predict cardiovascular disease in advance using the analyzed results for the autonomic balance from taking the spectral analysis of heart rate and the state of the blood vessel for analyzing APG(acceleration plethysmogram).

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.6
• /
• pp.1087-1094
• /
• 2008

This study describes a system for human sensibility evaluation using PPG(photoplethysmogram) signal and biofeedback algorithm to respond the bad(negative) mood. For this objective, PPG signals for two emotional states(positive/negative) are collected. To evoke the test emotions, happy(or joyful) and sad(or irritating) movie files are collected and played in subjects' monitor. From the acquired PPG signal, the heart rate variability(HRV) is calculated. Using the HRV and its FFT spectra, the human sensibility is evaluated. Since the heart is a representative organ which is controlled by the autonomic nervous system(ANS), the ANS may reflect the changes in emotion. The biofeedback algorithm is designed with motion image player interacting with the results of the sensibility evaluation. It was shown that HRV was changed according to the subject's emotions. Accordingly, the sensibility evaluation test showed feasibility of the our method.