• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1421-1422
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• 2015

본 연구는 스트립 힘센서에 기반한 무구속 호흡측정에서 스트립센서 최적 위치를 고찰하는 것을 주목적으로 한다. 이를 위해 압전센서를 사용하여 스트립 힘센서를 제작하였으며, 머리, 흉부, 복부 아래에 위치시켜 호흡성분을 검출하였다. 호흡성분 측정 정확성은 온도센서를 사용하여 코에서 동시에 측정된 기준 호흡과, 각 위치에서 측정된 결과의 비교를 통해 분석하였다. 결과적으로, 12명의 피험자를 대상으로 실험을 수행한 결과, 스트립센서를 사용하여 측정된 호흡간격은 기준센서 대비 $1.3669{\pm}0.5639$ 초 (머리), $0.9844{\pm}0.6336$ 초 (흉부), $0.7133{\pm}0.5185$ 초 (복부)의 평균절대오차를 보였다. 이는 복부에서 검출된 호흡성분이 기준호흡과 가장 유사함을 보여준다.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.482-483
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• 2008

본 연구는 수면 중 무구속적 방식으로 에어 베개에 부착한 PPG 센서에서 호흡 및 심박을 검출하는 방법을 제안하였다. 본 연구에서 사용된 반사형 PPG 센서는 광원이 피부로 투과되어 혈관의 이완 및 수축 정도를 측정할 수 있다. 반사형 PPG 센서로부터 하드웨어 모듈을 통과한 생체 신호는 AD 변환되어 PC로 전송된다 PPG에서 검출된 분당 심박 수는 전송된 신호의 밸리점간의 시간 간격을 이용하여 추출하며 호흡 신호는 밸리점의 크기를 연결하여 추출하였다. 검출된 호흡 신호와 기준 호흡 신호간의 상관성을 확인하기 위해 기준신호로 호흡과 심박을 동시에 측정하여 그 결과를 분석하였다. PPG 센서로부터 획득한 심박 및 호흡 신호는 기준신호들과 높은 상관성을 가지며 호흡시 발생하는 움직임과 호흡 속도에 영향을 받는다는 것을 알 수 있었다.

• Science of Emotion and Sensibility
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• v.21 no.1
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• pp.35-44
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• 2018

This study suggests the sensing method of the Three-dimensional respiration rate sensor based on surface area changes, and exploring the design direction of the three-dimensional breathing sensor and the design orientation of the garment. To achieve this, two types of three-dimensional respiration rate sensor were produced, and the study of the dummy and the subjects studied. The study I investigated the possibility of measurement of the three-dimensional respiration sensor by the study variables of the sensor type and speed of respiration. The study II proposes a suitable type of sensor for each of the three measuring positions in addition to the study variables in the study I. To evaluate accuracy, reproducibility, and reliability of the three-dimensional respiration rate sensor, the BIOPAC was used to measure the respiration rate simultaneously with the three-dimensional respiration rate sensor. Through all these results of the experiment, it explored the possibility of measurement of the three-dimensional respiration sensor for the dummy. It also proposed a suitable type of sensor by measuring the respiration rate for the human body.

• Journal of the Korea Society of Computer and Information
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• v.19 no.11
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• pp.33-41
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• 2014

In this paper, we implemented a system to measure respiration rate with nonrestraint sensors comfortable for people to do their everyday life. The proposed system consists of a pad covered with a Piezoelectric sensor, a respiration measuring device able to send the signal data after amplifying and filtering the source signals to the viewer, a viewer providing sensor data visualization and implementing the respiration measuring algorithm. The algorithm is based on a breathing cycle with the local peak points extracted from threshold on sensor data. Respiration measurements on 3 subjects were performed by changing moving averages and thresholds. The proposed system showed less than 5% error rate when proper moving averages are N=50~60 and a range of thresholds is 800~1300. The system will contribute to preventing suffocation during sleep for infants and the elderly living alone.

• Science of Emotion and Sensibility
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• v.24 no.4
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• pp.69-78
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• 2021

The development of smart healthcare wearables for health is accelerating. Among them, many wearable products using EMS electrical stimulation, which is one of the active research fields, have been released. However, the EMS wearable, which has been studied or released, is released in a comprehensive full-body suit that does not focus on muscle segmentation or a belt that covers the entire abdomen. Therefore, this study intends to use two breathing methods by applying an EMS pattern that subdivides specific muscles and attach a stretch sensor that can measure breathing to the abdominal pressure belt. The measurement method was conducted by inhaling and exhaling, and the subjects were 10 men in their 20s with healthy bodies. As a result of this study, the sensor's sensitivity was 5 and 3 mm, and the basic sensor in both thoracic and abdominal breathings and the EMS abdominal pressure belt showed improved respiration activation after applying electrical stimulation before and after application. It is concluded that, because of the two patterns produced based on the physical function, the difference in respiration activation effect and sensitivity between sensors could be confirmed with three sensors rather than not applying electrical stimulation suitable for the respiration method. Based on the results of this study, a follow-up study aims to develop breathing smart clothing that can be monitored in real time in clothing-type wearable products that incorporate EMS patterns and stretch sensors.

• Journal of the Korean Society of Radiology
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• v.9 no.7
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• pp.425-431
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• 2015

Measurement accuracy was evaluated for the respiratory air flow transducer developed for applications under emergent situations. Pressure-Flow calibration equation was obtained by acquisition of air flow signals from the transducer in response to 6 flow waveforms, similar to those of artificial ventilation, generated by the standard flow generator system. Tidal volume and maximal flow rate were calculated on the flow signal then compared with the error-free data obtained by the linear displacement transducer of the flow generator system. Mean relative error of the tidal volume was within 3% and that of the maximal flow rate, approximately 5%, demonstrating accurate enough measurements. Therefore, the transducer could be applied to emergent situations to monitor the respiratory air flow signal as well as diagnostic parameters in real time.

• Science of Emotion and Sensibility
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• v.21 no.1
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• pp.83-90
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• 2018

The purpose of this study is for fundamental research of meditation smart wear for physical and mental healing, and researching method for monitoring phase of meditation through textile by measuring the number of abdominal respiration when meditating. For this purpose, the research implemented Single Wall Carbon Nano-Tube (SWCNT) based strain gauges type textile sensor, considered reliability and validity of respiratory sensing, and analyzed efficiency of respiratory sensing based on body parts comparatively. The first preliminary experiment was to evaluate the performance of textile sensor through abdominal model dummy which open and shut of 5 cm repeatedly for 2 minutes at the rate of 0.1Hz in order to simulate abdominal respiration. It concluded signal efficiency between reference sensor(BIOPAC) and textile respiratory sensor appears statistically significant (p<0.001). The second experiment were conducted with 4 subjects doing abdominal respiration under same conditions, and after comparing the signal values between two sensors from 4 attached locations(around center and sides of omphali and phren), center of omphali and sides of phren were selected as suitable location for measuring meditational breathing as they showed large and stable signals. In result, this research aimed for implementing of the textile sensor for sensing meditational breathing of long respiration cycle, review of reliability and validity for sensing number of meditational respiration with the sensor and consideration of sensing efficiency by sensing location on body parts.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.2
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• pp.45-51
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• 2013

In this paper, a driver's drowsy detection sensor system based on the respiration is investigated. The sensor system consists of a piezoelectric pressure sensor attached at the abdominal region of the seat belt and a personal computer. The piezoelectric pressure sensor was utilized for the measurement of pressure variations induced by the movement of the driver abdomen during breathing. The signal processing software for detecting driver's drowsiness was produced using the Labview. The experiments were performed with 30 years male driver. The amplitude of the respiration at awake state was larger than one at the drowsy state. On the contrary, the respiration rate at awake state was lower than one at the drowsy state. The drowsy detection sensor system developed based on the experimental could successfully detect the driver's drowsy on real-time.

• Science of Emotion and Sensibility
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• v.22 no.1
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• pp.89-100
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• 2019

Sleep apnea, a medical condition associated with a variety of complications, is generally monitored by standard sleep polysomnography, which is expensive and uncomfortable. To overcome these limitations, this study proposes an unconstrained wearable monitoring system with stretch-fiber sensors that integrate with the wearer's clothing. The system allows patients to undergo examinations in a familiar environment while minimizing the occurrence of skin allergies caused by adhesive tools. As smart clothing for adult males with sleep apnea, long-sleeved T-shirts embedding fibrous sensors were developed, enabling real-time monitoring of the patients' breathing rate, oxygen saturation, and airflow as sleep apnea diagnostic indicators. The gauge factor was measured as 20.3 in sample 4. The maximum breathing intake, measured during three large breaths, was 2048 ml. the oxygen saturation was measured before and during breath-holding. The oxygen saturation change was 69.45%, showing a minimum measurable oxygen saturation of 70%. After washing the garment, the gauge factor reduced only to 18.0, confirming the durability of the proposed system. The wearable sleep apnea monitoring smart clothes are readily available in the home and can measure three indicators of sleep apnea: respiration rate, breathing flow and oxygen saturation.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1423-1424
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• 2015

본 연구는 IoT 환경에서 수면 중 비정상호흡 모니터링을 위한 모듈개발 사전연구로, 베개 안에 삽입할 수 있는 가속도, 진동 측정 모듈을 제작하고, 측정된 신호를 기반으로 수면 중 발생하는 호흡활동을 관찰하는 것을 목적으로 한다. 이를 위하여 압전센서 및 3축 가속도 센서를 내장한 진동, 가속도 측정 모듈 프로토타입을 설계 및 제작하였으며, 파일럿 실험을 통하여 개발된 모듈의 동작을 확인하였다. 실험 결과 가속도 및 압전센서에서 획득된 신호에서 호흡성분이 검출되는 것을 확인하였으나, 샘플링율, 센서 민감도 설정에 따라 코골이 성분은 검출되지 않았다.