• 대한환경공학회지
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• 제35권10호
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• pp.717-723
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• 2013

대한민국 환경부는 전국 대도시 측정소의 절반 이상에서 초미세먼지(Particulate Matter, $PM_{2.5}$) 농도가 기준치를 초과함으로서 국민의 건강보호를 위한 초미세먼지 제거대책을 추진 중에 있다. 전주시 중심가에서 여러 가지 주행조건을 달리하고 주행 중에 승용차내 초미세먼지를 측정한 결과 공기순환모드(Actuator)를 내기모드로, 송풍기(Blower)를 2단으로 조절한 경우에 초미세먼지의 감소속도가 가장 신속하고 낮은 농도를 유지하였다. 주행중에 창문을 열면 외부의 오염원 진입과 더불어 내부 먼지의 비산이 발생하였으며 탑승인원의 증가도 초미세먼지의 비산을 유발하였다. 공기 청정용 필터는 현재 사용중인 절곡 폴리프로필렌 부직포가 가장 우수했으나, 초미세먼지와 함께 휘발성 유기물질의 제거를 위하여는 탄소흡착제인 활성탄소섬유(Activated Carbon Fiber Filter) 부직포 필터의 사용이 훨씬 효과적일 것으로 판단된다.

• 대한의용생체공학회:의공학회지
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• 제35권5호
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• pp.125-131
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• 2014

The purpose of this study is to verify the utility of reflected photoplethysmography sensor using two green light emitting diodes that influenced by ambient light. Recently it has been studied that green light emitting diode is suitable for light source of reflected photoplethysmography sensor at low temperature and high temperature. Another study showed that, green light is better for monitoring heart rate during motion than led light. However, it has a bad characteristic about ambient light noise. To verify the utility of reflected photoplethysmography sensor using green light emitting diode, this study measures the photoplethysmography signal that is distorted by ambient light and will propose a solution. This study has two parts of research method. One is measurement system that composed sensor and board. The sensor is made up PE-foam and Non-woven fabric for flexible sensor. The photoplethysmography signal is measured by measurement board that composed high-pass filter, low-pass filter and amplifier. Ambient light source is light bulb and white light emitting diode that has three steps brightness. Photoplethysmography signal is measured with lead II electrocardiography signal at the same time and it is measured at the finger and radial artery for 1 minute, 1000 Hz sampling rate. The lead II electrocardiography signal is a standard signal for heart rate and photoplethysmography signal that measured at the finger is a standard signal for waveform. The test is repeated 3 times using three sensor. The data is processed by MATLAB to verify the utility by comparing the correlation coefficient score and heart rate. The photoplethysmography sensor using two green light emitting diodes is shown better utility than using one green light emitting diode and red light emitting diode at the ambient light. The waveform and heart rate that measured by two green light emitting diodes are more identical than others. The amount of electricity used is less than red light emitting diode and error peak detectability factor is the lowest.