• 대한의용생체공학회:의공학회지
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• 제35권3호
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• pp.55-61
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• 2014

In sleep monitoring system, polysomnography (PSG) is the gold-standard but previous studies revealed that attaching numerous amount of sensors disturb sleep during the test which is the fundamental disadvantage of PSG. We suggest an unconstrained rapid-eye-movement (REM) sleep monitoring method measured with polyvinylidene (PVDF) film-based sensor for the normal and the obstructive sleep apnea (OSA) patients. Nine normal subjects and seventeen OSA patients have participated in the study. During REM sleep, rate and variability of respiration are known to be greater than in other sleep stages. Based on this phenomena, respiratory signals of participants were unconstrainedly measured using the PVDF-based sensor with the PSG and REM sleep were extracted from the average rate and variability of respiration. In epoch-by-epoch REM sleep detection, proposed method classified REM sleep with an average sensitivity of 72.3%, specificity of 92.5%, accuracy of 88.9%, and kappa statistic of 0.60 compared to the results of PSG. Student's t-test showed no significant difference between the results of normal and OSA group. This method is potentially applicable to REM sleep detection in homing environment or ambulatory monitoring.

• 대한임베디드공학회논문지
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• 제10권1호
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• pp.33-40
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• 2015

The number of people who are suffering from chronic sleep disorder has been growing dramatically in modern era. In order to diagonse the sleep disorder, sleep doctors perform polysomnography: Patients sleep with attaching several vital sign sensors on their body, and doctors monitor the patients in order to find the exact reason of the sleep disorder. Typical polysmonography makes patients sleep with several sensors on their bodies, which prevents the patients from making a comfortable sleep. Furthermore, it is impossible to have a long-term monitoring since the measurements should be done in sleep hosiptal within a few hours. In order to tackle these problems in the typical polysomnography, we envision the development of a non-contact long-term home polysomnography system using UWB radar and related technologies such as multi-modal signal processing.

• 대한의용생체공학회:의공학회지
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• 제26권6호
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• pp.373-381
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• 2005

The respiratory and heart beat signals are the fundamental physiological signals for sleep monitoring in the home. Using the air mattress sensor system, the respiration and heart beat movements can be measured without any harness or sensor on the subject's body which makes long term measurement difficult and troublesome. The differential measurement technique between two air cells is adopted to enhance the sensitivity. The concept of the balancing tube between two air cells is suggested to increase the robustness against postural changes during the measurement period. With this balancing tube, the meaningful frequency range could be selected by the pneumatic filter method. The mathematical model for the air mattress and balancing tube was suggested and the validation experiments were performed for step and sinusoidal input. The results show that the balancing tube can eliminate the low frequency component between two cells effectively. This technique was applied to measure the respiration and heart beat on the bed, which shows the potential applications for sleep monitoring device in home. With the analysis of the waveform, respiration intervals and heart beat intervals were calculated and compared with the signal from conventional methods. The results show that the measurement from air mattress with balancing tube can be used for monitoring respiration and heart beat in various situations.

• 한국전자통신학회논문지
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• 제17권3호
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• pp.491-498
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• 2022

우리의 일상생활에서 양질의 수면은 행복 지수와 밀접한 관계가 있다. 사람들은 수면 장애를 만성 질환으로 인식하든 아니든 많은 어려움을 호소하고 있으며 일상생활에서 수면 중에 호흡 곤란을 경험하는 경우가 종종 발생한다. 수면 중에 호흡 관련 장애를 자동으로 인식하는 것은 매우 중요하나 현실적으로 매우 어렵다. 본 논문은 이러한 문제를 해결하기 위해 가정에서 건강관리를 위해 모바일 기반의 비접촉 수면 모니터링을 제안한다. 수면 중 호흡 신호는 스마트 폰의 소리 센서를 이용하여 호흡 신호를 수집하고, 신호의 특징을 추출, 호흡의 주파수, 진폭, 호흡의 주기, 호흡의 패턴을 분석한다. 모바일 건강이 모든 문제를 해결하지는 못하나 개인의 건강 상태의 조기 발견과 지속적인 관리를 목적으로 하고, 일반 가정의 침실에서 스마트 폰으로 추가 센서 없이 수면 중에 호흡과 같은 생리학적 데이터 모니터링의 가능성을 보여준다.

• 아동학회지
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• 제37권3호
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• pp.13-26
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• 2016

Objective: The purpose of this study was to investigate the relationship between sleep duration and school adjustment of elementary-, middle-, high-school youth and to verify the mediating effects of parenting behavior. Methods: We analyzed the data from Wave 4 of the first-grade panel of elementary school and Waves 1 and 4 of the first-grade panel of middle school in Korean Children and Youth Panel Survey (KCYPS), including 1,703 fourth graders, 2,119 seventh graders, and 2,108 tenth graders. Multiple regression was used for the data analyses. Results: The results of this study were as follows. First, longer sleep duration was associated with a higher level of school adjustment in fourth grade. In contrast, longer sleep duration was associated with a lower level of school adjustment in seventh and tenth grades. Second, longer sleep duration was related to a higher level of discipline through reasoning in fourth grade. However, longer sleep duration was related to a lower level of parental monitoring in seventh and tenth grades. Third, the relationship between sleep duration and school adjustment was mediated by parenting behavior. Discipline through reasoning had a mediating effect in fourth grade, but the mediating effect of parental monitoring was found in seventh and tenth grades. Conclusion: These results suggest a differentiated approach on sleep duration in accordance with developmental stage and the need for parent education.

• 전기학회논문지
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• 제67권7호
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• pp.892-897
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• 2018

Due to population aging, an increase in the number of patients with chronic illnesses, and an increase in the number of single-person households, monitoring of health status in everyday life without the need for a hospital has become very important. For this reason, researches on various health care devices have been attempted, among which wearable devices are attracting much attention. In this paper, we propose a new ring-type wearable device for next generation healthcare. On the inner side of the ring, a metal electrodes for GSR measurement and an optical sensor for measurement of pulse wave signals of two wavelengths of red and near-infrared light were mounted. In addition, it was equipped with an acceleration sensor, and information about the degree of motion could be obtained. In this paper, it is shown that a health monitoring device can be implemented in the form of a ring, and the measured signals can be used to calculate heart rate, oxygen saturation, sleep time and sleep efficiency. Through the advanced algorithm, it is expected that we can extract various health information, especially sleep related health information by using the ring device, and it is also expected that it can contribute to the implementation of wearable healthcare effectively.

• 감성과학
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• 제22권1호
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• pp.89-100
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• 2019

본 연구에서는 수면무호흡증이 다양한 합병증을 유발하는 질병으로서, 이를 위한 표준화된 수면다원검사가 고가이며 측정이 불편함을 고려하여, 환자가 익숙한 환경에서 검사를 받을 수 있도록 스트레치 섬유센서를 이용한 무구속 상태의 웨어러블 모니터링 시스템을 개발하고자 한다. 또한, 의복과 일체화된 디자인으로 제품화하여 그 유용성을 제안하고자 한다. 성인 남성용 롱 슬리브 티셔츠 형태로 착용형 수면무호흡 모니터링 스마트 의류를 개발하여, 수면무호흡 진단 지표 중 섬유형 센서를 기반으로 측정하는 호흡수(breathing rate)측정용 섬유센서, 산소포화도(oxygen saturation), 호흡기류(airflow)를 실시간 측정하였다. 최적의 조합비 샘플 4가지를 통한 gauge factor를 측정한 결과, gauge factor 20.3을 확인하였고, 3회 숨을 크게 내쉴 때 호흡유량이 최대 2048ml였다. 산소포화도 69.45%로 최소 측정 가능 산소포화도 70% 정도의 결과를 나타내었다. 세탁 후 인장에 따른 센서 성능 평가 결과는 전체적으로 gauge factor 18 수준의 값으로, 세탁에 대한 내구성이 입증되었다. 본 연구를 통하여 수면무호흡증 환자의 수면효율이 떨어지고 여러 합병증을 동반하는 문제에 대해, 가정에서 쉽게 사용할 수 있는 착용형 수면무호흡 모니터링 스마트 의류를 개발하여 호흡수, 호흡유량, 산소포화도의 3가지 지표를 측정 가능함을 확인하였다.

• 대한의용생체공학회:의공학회지
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• 제44권6호
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• pp.392-403
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• 2023

This study presents a new hybrid fNIRS-EEG system to meet the demand for a lightweight and low-cost sleep pattern monitoring device. For multiple-channel configuration, a six-channel electroencephalogram (EEG) and a functional near-infrared spectroscopy (fNIRS) system with eight photodiodes (PD) and four dual-wavelength LEDs are designed. To enhance the convenience of signal measurement, the device is miniaturized into a patch-like form, enabling simultaneous measurement on the forehead. Due to its fully integrated functionality, the developed system is advantageous for performing sleep stage classification with high-temporal and spatial resolution data. This can be realized by utilizing a two-dimensional (2D) brain activation map based on the concentration changes in oxyhemoglobin and deoxyhemoglobin during sleep stage transitions. For the system verification, the phantom model with known optical properties was tested at first, and then the sleep experiment for a human subject was conducted. The experimental results show that the developed system qualifies as a portable hybrid fNIRS-EEG sleep pattern monitoring device.

• 기본간호학회지
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• 제19권4호
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• pp.434-443
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• 2012

Purpose: This study was conducted to investigate sleep patterns in nursing students as measured by an automated wireless sleep tracker and self-reported sleep scales. Methods: Data were collected from October, 2011 to May, 2012. ZQ (a symbolic number that measures the quality and quantity of sleep) was calculated from the automated wireless sleep tracker. Pittsburgh Sleep Quality Index-Korean version, Sleep scale A, and sleep satisfaction were used as self-report sleep scales. Female nursing college students (n=37) were recruited by convenience sampling. Before going to bed, they were asked to put on a head-band type sleeping sensor and to move it the next morning. Every student slept 2~4 nights with the sleep tracker. Data were collected for 86 (91.4%) of 94 nights' sleep. The students were also requested to fill in the PSQI-K, sleep scale A, and sleep satisfaction. Results: The only statistically significant correlation was between ZQ and sleep satisfaction (r=.869, p=.026). The biggest obstacle in using this device was putting on the head-band type sensor. Conclusion: Validity of the wireless sleep tracker was verified in part. The usefulness of this device in nursing research and practice was identified. Further evaluation need to be conducted with various populations.

• 한국산학기술학회논문지
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• 제19권10호
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• pp.603-609
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• 2018

수면 중 돌연사는 급성 심근경색 등의 이유로 노인 뿐 만 아니라 영아나 20~40대와 같은 비교적 젊은 층에서도 종종 발생하고 있다. 수면 중 돌연사는 미리 예측하기 어려우므로 이를 방지하기 위해서는 수면 모니터링이 필요하다. 본 논문에서는 별도의 센서 부착 없이도 수면 중 돌연사 감지를 할 수 있는 새로운 비디오 분석 방법을 제안한다. 제안하는 비디오 분석 방법에서는 호흡에 의한 미세 움직임을 감지하기 위해 모션 증폭 기법을 적용한다. 모션 증폭을 적용했는데도 프레임 간 차이가 거의 없는 경우, 모션이 존재하지 않아 돌연사 가능성이 있는 것으로 판단한다. 수면 중인 아기를 촬영한 비디오 두 편에 대해 모션 증폭을 적용한 결과, 호흡에 의한 미세 모션을 정확하게 감지하였고, 이는 수면 상태와 돌연사를 구분하는데 유용할 것으로 판단되었다. 제안하는 비디오 분석 방법은 신체에 센서 부착을 필요로 하지 않으므로 아기를 키우는 가정이나 독신 가정에서 편리하게 활용될 수 있을 것이다.