• 센서학회지
• /
• 제22권1호
• /
• pp.76-83
• /
• 2013

A real-time wireless monitoring and analysis methods using the wearable PPG sensor to estimate cardiovascular condition is studied for ubiquitous healthcare service. A small size and low-power consuming wearable photoplethysmogram (PPG) sensor is designed as a wrist type device and connected with the IP node assigned its own IPv6 address. The measured PPG waveform in the IP node is collected and transferred to a central server PC through the IP-enabled wireless network for storage and analysis purposes. A monitoring and analysis program is designed to process the accelerated plethysmogram (APG) waveform by applying the second order derivatives to analyze systolic waves as well as heart rate variability analysis from the measured PPG waveform. From our results, the features of cardiovascular condition from individual's PPG waveform and estimation of vascular compliance by the comparison of APG-aging index (AI) and ratio of LF/HF are demonstrated.

• 센서학회지
• /
• 제15권5호
• /
• pp.334-340
• /
• 2006

A compact biosignal monitoring device was developed. Electrodes for electrocardiogram (ECG) and a LED and silicon detector for photoplethysmogram (PPG) were used. A lead II type was arranged for ECG measurement and reflected light was measured at the finger tip for PPG. A single chip microprocessor (model ADuC812, Analog Device) controlled a measurement protocol and processed measured signals. PPG and ECG had a sampling rate of 300 Hz with 8-bit resolution. The maximum power consumption was 100 mW. The microprocessor computed pulse transit time (PTT) between the R-wave of ECG and the peak of PPG. To increase the resolution of PTT, analog peak detectors obtained the peaks of ECG and PPG whose interval was calculated using an internal clock cycle of 921.6 kHz. The device was designed to be operated by 3-volt battery. Biosignals can be measured for $2{\sim}3$ days continuously without the external interruptions and data is stored to an on-board memory. Our system was successfully tested with human subjects.

• 한국감성과학회:학술대회논문집
• /
• 한국감성과학회 2001년도 추계학술대회 논문집
• /
• pp.169-172
• /
• 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.

• 전기학회논문지
• /
• 제59권6호
• /
• pp.1131-1135
• /
• 2010

The development of modern civilization result from the abundance of material. Yet modern people live with chronic mild stress. Excessive chronic mild stress leads to various diseases. From the risk of the disease in order to protect our bodies need to manage chronic mild stress. The purpose of this study is to inspection the effectiveness of detecting in chronic mild stress using the Multi-sensor system. The Multi-sensor system is designed that can be measure three kinds of vital signals of chronic mild stress for the detection. First Photoplethysmogram(PPG), second Electro Dermal Activity(EDA), third Skin Temperature(SKT). The ages and occupations exposed to chronic mild stress, people often use out of this system was applied to dairy products(Pen). In addition, vital signals that occur when the variety of noise was used to remove the accelerometer. Chronic mild stress by the analysis of measured vital signals from Multi-sensor system to the measurement information to a PC to a wireless transmission(Bluetooth). In this study, using Multi-sensor system writing conditions and a variety of situations in the movement to measure vital signals and measurement results verified the accuracy and reliability. Through this measure chronic mild stress in everyday life and managing to maintain will help more healthy lifestyle.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2022년도 춘계학술대회
• /
• pp.660-662
• /
• 2022

COVID-19 장기화의 여파로 인해 스트레스 및 정신적 질환을 겪는 현대인이 늘어나고 있다. 최근에는 LED 조명을 이용하여 집중력 향상, 스트레스 완화, 피부관리, 수면의 질 개선 등을 위해 다양한 방법으로 컬러테라피가 연구 되고 있다. 본 논문에서는 사람의 심신 상태를 분석하기 위해 PPG(Photoplethysmogram) 센서를 이용하여 맥파를 계측하고 심박변이도를 추출한다. RGBLED와 아두이노를 이용하여 심리상태 안정에 주로 사용되는 여러 파장의 색상조명을 제작하고, 심신상태의 변화에 따라 자동으로 색상을 변경해주는 무드등 시스템을 제안한다.

• Journal of Magnetics
• /
• 제15권4호
• /
• pp.209-212
• /
• 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.

• 한국감성과학회:학술대회논문집
• /
• 한국감성과학회 2009년도 추계학술대회
• /
• pp.160-163
• /
• 2009

본 연구는 생리신호에 의한 집중된 시선과 집중하지 않는 시선을 분류하고자 한다. 이를 검증하기 위해 시각적으로 높은 집중과 낮은 집중을 요구하는 두가지 과제를 피실험자에게 제시하고 PPG(Photoplethysmogram), GSR(Galvanic Skin Response) 그리고 SKT(Skin Temperature)센서를 사용한 자율신경계 반응과 시선 움직임을 측정하였다. 과제는 $3{\times}3$으로 화면 구역을 나누고 각 구역에 문자를 제시하고 역방향 문자를 찾도록 하였다. 실험에는 20 명의 대학생이 참여하였으며, 1 번의 실험에 12 종류의 다른 문자배열을 제시 받았으며 1 번의 연습을 포함하여 총 5 회 실시후 데이터를 분석하였다. 높은 집중일 경우와 낮은 집중일 경우를 T-test 분석 결과, 자율신경계에서는 높은 집중일 경우 PPG 주파수가 증가하고 GSR과 SKT는 감소한 결과를 보였다. 따라서 시선의 집중도에 따라 다른 자율신경계 반응과 시선반응을 보이는 것을 확인하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.1978_1979
• /
• 2009

Heart rate may be a very important parameter in human health. To extract heart rate, the electrocardiogram(ECG) is commonly used. But the ECG acquisition procedure is somewhat complex. On the other hand, the acquisition of pulse wave or photoplethysmogram(PPG) is very easy. However, the peak of PPG is not so sharp as ECG. This study tries to enhance the performance of period detection in PPG signal. The method uses the average slopes around the main peak. The crossing point of the increasing and the decreasing slopes is selected as the peak point of heart rate period. The proposed method showed smoothed heart rate graph and reduced irregularity in heart rate values.

• 대한의용생체공학회:의공학회지
• /
• 제23권6호
• /
• pp.485-489
• /
• 2002

본 연구는 동맥의 압력에 따라 변하는 맥파전달시간(pulse transit time, PTT)을 이용하여 호흡노력을 검출하기 위하여 호흡에 따른 PTT 변화를 관찰하였다. PTT는 심전도의 R파 피크로부터 말초에서 나타나는 광전용적맥(photoplethysmograph, PPG)의 최대기울기점까지 시간이다. 생체 신호를 아날로그-디지탈 변환하여 PC에서 매번 심장주기마다 PTT를 측정하였으며 이산적인 결과를 스플라인 보간법을 사용하여 그래프로 제시하였다. 소프트웨어는 $C^{++}$을 사용하여 windows 환경에서 운용하였다. 안정상태 호흡 시에는 호흡의 주기와 일치하는 주기적인 PTT의 변화가 있었다. 호흡 심도를 증가시킴에 따라 PTT의 진폭이 증가하였으며, 기도저항을 증가시킨 경우에도 PTT의 진폭이 증가하는 양상을 보였다. 이러한 결과는 PTT가 호흡노력에 따라 반응하는 것을 시사한다. 아울러 PTT를 이용한 호흡노력 모니터링은 비침습적 방법으로써 호흡장애를 감시하는데 유용하게 사용될 수 있음을 시사한다.

• 전기학회논문지
• /
• 제62권7호
• /
• pp.1020-1026
• /
• 2013

Multirate filtering process on the biological signals like Electrocardiogram (ECG) and Photoplethysmogram (PPG) can be defined as the digital signal processing algorithm in which the sampling rate varies to omit or interpolate the intermediate values between the sampled data. With this aim, we suggest a new multirate filtering algorithm by deleting the extraneous data to eliminate the unwanted degradations such as granular noise due to the usage of high sampling frequency and simultaneously to detect the fiducial features of ECG and PPG with reducing the complexity of resolving fiducial points such as R-peak, Pulse peak and Pulse Transit Time (PTT). After the experimental simulations performed, we can conclude the fact that we can detect the fiducial features of ECG and PPG signal in terms of R-peak, Pulse peak and PTT without the loss of accuracy even if we do not maintain the original sampling frequency.