• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.493-496
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• 2005

For home healthcare, the unconstrained measurement of physiological signal is highly required to avoid the inconvenience of users. The recording and analysis of the fundamental parameters during sleep like respiration and heart beat provide valuable information on his/her healthcare. 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. The differential measurement technique between two air cells is adopted to enhance the sensitivity. The balancing tube between two air cells is used to increase the robustness against postural changes during the measurement period. The meaningful frequency range could be selected by the pneumatic filter with balancing tube. ECG (Electrocardiography) and respiration sensor (plethysmography) were measured for comparison with the signal from air mattress. To extract the heart beat information from air pressure sensor, digital signal processing technique was used. The accuracy for breathing interval and heart beat monitoring was acceptable. It shows the potentials of air mattress sensor system to be the unconstrained home sleep monitoring system.

• 한국가구학회지
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• 제24권2호
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• pp.191-207
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• 2013

Bed for elderly and disabled, including the United States developed the industry Americas, and European countries, mainly in the production of products has dominated the world market. In large hospitals, and dependent products are sold at high prices. On the other hand, improvement of living standards of our country and to the advancement of residential culture of the demand for luxury products is increasing. The study of the elderly Edition mattresses have been developed mainly in Europe to maximize the use of sleep can increase the efficiency of products has been studied. Due to the increase in elderly population Elderly Hospital, which is installed in the elderly silver town Edition requires the dissemination of the mattress in the bedroom several times a day resting and sleeping, eating, etc. Designing a variety of actions are needed. Edition of the elderly in Korea developed the design of bed with bed design and the manufacturer and the Institute for Ergonomics, welfare agencies and to build organic cooperation system under the direction of a professional designer to develop and you need to configure the space and the results of such actions by the distribution of cheap materials, ergonomic mattress for optimal development of behavior analysis to the need to promote the convenience of the user.

• 대한의용생체공학회:의공학회지
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• 제38권4호
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• pp.153-162
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• 2017

The present study proposes a system that can detect sleep-disordered breathing automatically using an air mattress and oxygen saturation. A thin air mattress was fabricated to reduce discomfort during sleep, and respiration signals were acquired. The system was configured to be synchronized with a polysomnography to receive signals simultaneously with other bio-signals. The present study has been conducted with nine adult male and female patients with sleep-disordered breathing, and sleep-disordered breathing events have been detected by applying the signals acquired from the subjects to the rule-based detection algorithm. The sensitivity and positive predictive values were found to evaluate the performance of the system, which are 91.4% and 89.7% for all events, respectively. The comparison of apnea hypopnea index(AHI) between the polysomnography and the proposed method showed squared R-value of 0.9. This study presents the possibility of detecting sleep-disordered breathing at hospitals or homes using the proposed system.

• 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.

• 대한기계학회논문집B
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• 제37권11호
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• pp.1031-1036
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• 2013

종래의 모터 펌프를 이용한 매트용 온수보일러는 큰 유량을 공급할 수 있지만 모터 펌프의 진동과 소음이 큰 단점이 있다. 모터 펌프를 사용하지 않는 매트용 온수보일러의 경우 소음과 진동이 억제되는 장점이 있지만 감소된 유량으로 인해 매트의 온도 편차가 큰 단점이 있다. 본 연구에서는 기존 펌프 없는 온수보일러가 가지고 있는 문제점을 개선하여 순환유량을 증가시킨 새로운 온수 보일러 방식을 제안하고 실험을 통해 그 성능을 입증하였다. 성능 실험 결과 순환 유량의 증가로 매트 온도 상승시간이 대폭 줄어들었으며 유입 온수와 유출 온수의 온도 편차도 많이 줄어들어 종래의 펌프 없는 온수보일러와 비교하여 성능 개선을 입증하였다.

• 근관절건강학회지
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• 제29권1호
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• pp.18-27
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• 2022

Purpose: A network meta-analysis was conducted to assess the comparative effects and ranks of repositioning for pressure ulcer prevention in adults. Methods: A network meta-analysis was performed in a frequency method, using the "netmeta" package of R software version 4.1. The effects of repositioning intervention were confirmed by the odds ratio. The comparative ranking of the repositioning effects was confirmed using the cumulative probability (P-score). Results: Seven intervention studies were included in this study. Based on the P-score, the use of the repositioning system was ranked as the most effective among all interventions (P-score 78.7%). Next was 3~4-hour repositioning combined with memory foam mattress use (P-score 77.2%), use of wearable sensor (P-Score 61.4%), 2-hour repositioning combined with memory foam mattress use (P-score 59.1%), 2-hour repositioning combined with powered air pressure redistribution mattress use (P-score 18.0%), and 4-hour repositioning combined with powered air pressure redistribution mattress use (P-score 18.0%). Conclusion: This study provides information on the relative comparative value of various repositioning interventions to prevent pressure ulcers using network meta-analysis. This is expected to be useful for nurses' decision-making when applying repositioning interventions in clinical practice

• 대한의용생체공학회:의공학회지
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• 제35권6호
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• pp.177-184
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• 2014

Continuous monitoring of heart rates and respiratory rates for newborns or infants is very important since the abnormal breathing and heart problems can threaten the life of newborns or infants. A noncontact baby monitoring system based on a Doppler radar and an air mattress was designed. The Doppler radar was used to acquire respiratory signals and the air mattress was employed to obtain heart rates. The performance of the designed system was evaluated using a commercialized infant simulator ($Simbaby^{TM}$) and a respiration belt transducer was used to measure respiration rates as a reference. Results for respiratory rates revealed that the correlation coefficients between I-and Q-channel and the respiration belt were 0.84 and 0.91 and the mean ${\pm}$ standard deviations of errors between them were $1.66{\pm}1.92$ (bpm) and $0.88{\pm}1.65$ (bpm). Heart rates showed that the correlation coefficient between air mattress and set value of the simulator was 0.73 and the mean ${\pm}$ standard deviation of errors between them was $1.09{\pm}3.45$ (bpm). These results indicate that the designed system holds the potential as an effective monitoring tool for continuous monitoring heart rates and respiratory rates of newborns or infants.

• 한국의류학회지
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• 제16권3호
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• pp.285-298
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• 1992

In this study, bedclimate was investigated depending on various bedquilts used oin ondol in summer. The environmental room condition was maintained at 26: $1^{\circ}C,\;75{\pm}3\%$ R.H., while the ondol surface was kept at $25{\pm}1^{\circ}C$ without heating. The types of bedquilts were hemp, cotton, quilt made of polyester padding with polyester/cotton cover. Two healthy young women were subjected for seven hours' sleep with two replications for this study. The results are as follows. 1) The range of the temperature under the mattress ($25.2\~32.4^{\circ}C$) was lower than that of the temperature on the mattress ($28.8\~35.5^{\circ}C$), or that of the temperature inside the bedquilts ($30.3\~34.4^{\circ}C$). The humidity inside the bedquilts increased during sleeping, and the range of R.H. was $58\~80\%$. 2) The ranges of bedclimate which subjects feel comfortable were $30.5\~33.8^{\circ}C$ on the mattress, $31.0\~34.9^{\circ}C$, $61\~74\%$ R.H. inside the bedquilts. At this range, the mean skin temper-ature of the subjects was $34.3^{\circ}C\~35.2^{\circ}C$. 3) When there was no heating, the weight of the bedding increased during sleeping, and the weight increase was largest in the case of mattress. 4) There were correlations among the skin temperature of three points of the body (abdomen, thigh, foot) and the temperature and R.H. inside the bedquilt. 5) The effect of the type of bedquilts on the microclimate and physiolosical responses were significant. 6) Generally, when there was no heating, the body heat was transferred to the ondol floor, in summer, heat was transferred mostly through the mattress.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 1996년도 학술발표회
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• pp.24-29
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• 1996

The objective of this research is to study on the formations of thermal stratification in a room in case of several furniture fires such as trashcan, chair, carpet, sofa, mattress and wardrobe as a fire starter in a residential room by performing the experimental studies. The uniformly distributed fire in case of carpet showed that the ignition and the initial growth period were relatively short while the fully developed period was considerably long. The concentrated fires such as the mattress and wardrobe showed that the ignitions and the initial growth periods were relatively long. When fire spread to only one direction, like the case for the trashcan with a regular shape, there was one peak of temperature profile, and for the irregular shaped furniture such as chair, sofa, mattress and wardrobe, there were two or more peaks. The interface heights for the furniture fires were around 1(m) mataining constant state. However, at the time of the maximum temperature, the interface height was lowered to 0.25(m)-0.75(m) from the floor

• 한국해양공학회지
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• 제30권2호
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• pp.109-116
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• 2016

A flexible concrete mattress (FCM) is a structural system for protecting submarine power or communication cables under various load types. To evaluate its of protection performance, a numerical analysis of an FCM under an anchor collision was performed. The explicit dynamics of the finite element analysis program ANSYS were used for the collision analysis. The influences of the steel reinforcement modeling and collision angle of the anchor on the collision behavior of the FCM were estimated. The FCM damage was evaluated based on the results of the numerical analysis considering the numerical modeling and collision environment.