• Journal of Magnetics
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• v.15 no.4
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• pp.209-212
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• 2010

Photoplethysmogram (PPG) and pressure pulse waveform (PPW) were compared and evaluated for the efficacy of stimulating knuckles by using the pulsed magnetic field. Both signals were observed simultaneously while the knuckles were exposed for 10 min to the pulsed magnetic field, with maximum field intensity of 0.8 T and transition time of 0.126 msec. After 5 min stimulation of the knuckles, the results showed that the aging indexes calculated from the second derivative of the PPG were increased from -1.913 to 0.072, and that of the PPW from -0.063 to 0.387. However, for the relatively long-term stimulation for 10 min, we found that the values of both the aging indexes of the second derivatives and augmentation index of the PPW returned to the starting level. The changes observed in characteristic factors such as the aging indexes of the second derivatives and augmentation index of the PPW indicate the potential of pulsed magnetic field stimulation as a therapeutic method for the treatment of patients with peripheral vascular disease.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.133-134
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• 2008

우리나라의 당뇨병 유병률은 경제발전과 식생활의 급속한 서구화로 빠른 속도로 증가하고 있다. 특히 당뇨병은 유병기간이 길수록 여러 합병증을 초래하는데 그 중 하나가 혈관경화증이다. 혈관 경화증은 신체 부위별로 그 진행 속도가 다르다. 광혈류측정법(PPG, photoplethysmogram)은 간편한 혈류량 측정방법으로 PPG 2차 미분 방법을 이용해서 혈관의 경화도를 진단할 수 있다. 이러한 PPG 2차 미분방법을 이용하여 당뇨병환자의 왼손과 오른손의 말초혈관 탄성도 차이를 정상인과 비교해 보았다. 실험결과 당뇨병환자와 정상인의 양 손가자 말초혈관 탄성도의 유의한 차이를 확인 할 수 있었다.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2001.11a
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• pp.169-172
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• 2001

There are many people who suffer from simulation sickness when immersing in virtual reality. In this study, we analyzed two photoplethysmogram(PPG) parameters - a second derivative parameter and power spectral density ratios - in order to relate PPG parameters with simulation sickness. 36 young, healthy subjects were participated in the experiment, and each subject was equipped with a PPG electrode during his or her immersion. Simulation sickness section was defined as a 7 - second section which starts from the point where a subject reported simulation sickness, and normal section as a same-length section where no physical stimuli was presented to him or her. We compared the PPG parameters of the simulation sickness sections with the normal sections, - d/a ratio is believed to have lower value during vasodilation and higher value during vasoconstriction, however, we could not find much difference in the parameter between normal and simulation sickness sections. We also compared 1 to 10Hz power spectral density ratios in normal sections with in simulation sickness section, and found that 6 density ratios among them have different value. Therefore, the density ratios might be utilized as parameters to detect simulation sickness of subjects.

• Journal of Physiology & Pathology in Korean Medicine
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• v.29 no.3
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• pp.230-239
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• 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 the Institute of Electronics and Information Engineers
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• v.54 no.5
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• pp.138-142
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• 2017

Photoplethysmography (PPG) is a simple and low-cost optical technique that can be used to detect blood volume changes in the microvascular bed of tissue. It is often used non-invasively to make measurements at the skin surface. In this paper, we described the implementation heart rate monitoring system using PPG sensor. Proposed system is collected data using PPG sensor and heart rate was detected using second derivative method. In order to verify the effectiveness of the proposed method, we performed the measurements of RR-intervals with a commercial medical device.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.125-126
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• 2008

현재, 우리나라 당뇨병의 유병률은 빠른 속도로 증가하고 있으며 당뇨병의 유병기간이 길수록 각종 합병증이 발생하며 더욱 심각한 증세를 나타내기도 한다. 그 중, 비만 및 고혈당, 당대사장애로 인한 당뇨병성 혈관 합병증과 말초 혈관 경화증이 많이 발병하고 있는 실정이다. 본 연구에서는 광혈류량 측정법(Photoplethysmograaphy)으로 손가락에서 얻어진 맥파의 2차 미분 분석을 통해 당뇨병으로 확진된 36명의 당뇨병 환자에 대해 말초혈관 경화도를 연령별로 비교하고자 하였다. 이때 사용한 PPG 파형의 2차 미분 분석 평가 인자는 a와 d이고, d/a는 혈관의 경화도를 의미하며 경화도가 클수록 d/a의 값은 감소하게 되고, 연령이 증가할수록 경화도는 증가하게 된다. 50대 미만의 당뇨병 환자의 d/a값은 $-0.32{\pm}0.12$, 50대는 $-0.48{\pm}0.13$, 60대는 $-0.55{\pm}0.16$, 70대 이상에서는 $-0.59{\pm}0.19$로 연령이 높아질수록 d/a값이 감소하는 것을 확인하였다. 또한, SPSS 13.0 for Windows(SPSS Inc, USA)의 Oneway ANOVA 분석 결과, 연령과 경화도는 통계적으로 유의한 차이를 보였다(p<0.05). 하지만 70대 이상의 당뇨병 환자 그룹에서는 유의한 차이를 확인할 수 없었다. 본 연구에서는 PPG 파형의 2차 미분 분석을 통하여 연령별 당뇨병 환자의 말초혈판 경화도를 비교하였으며, 향후 보완 연구를 통해 비침습적이고 간단한 방법으로 당뇨병 환자의 말초혈관 경화도를 객관적으로 평가하고 진단할 수 있는 시스템 개발로 당뇨병 환자들의 심혈관계질환 사전예방과 치료효과 판정에 도움을 줄 것으로 기대한다.

• Journal of Acupuncture Research
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• v.28 no.1
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• pp.101-108
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• 2011

목적 : 신정격 자침이 당뇨군과 정상군의 혈관변화에 미치는 영향을 알아보기 위해 가속도맥파를 이용한 실험을 설계하였다. 방법 : 20명의 당뇨군과 20명의 정상군에서 신정격 자침 이전과 이후, 2회에 걸쳐서 Cardio Peri SA6000을 이용하여 가속도맥파를 측정하였다. 가속도맥파의 b/a, c/a, d/a 및 연령지수를 통해 혈관상태를 평가하였다. 결과 : 1. 당뇨군과 정상군의 신정격 자침 이전 가속도맥파 측정에서 당뇨군이 정상군보다 b/a값(p=0.000), 연령지수(AI)(p=0.000)는 유의하게 높았으며, c/a값(p=0.000), d/a값(p=0.000)은 유의하게 낮았다. 2. 당뇨군에서 신정격 자침 이후 가속도맥파의 b/a값(p=0.004), 연령지수(p=0.012)는 유의하게 낮아졌으며, c/a값(p=0.026)은 유의하게 높아졌다. 3. 정상군에서 신정격 자침 이후 가속도맥파의 b/a값(p=0.025)은 유의하게 낮아졌다. 결론 : 신정격 자침이 당뇨로 인해 유발된 혈관의 탄력도 감소 및 노화를 다소 회복시킬 수 있는 것으로 사료된다.