• 대한임베디드공학회논문지
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• 제14권3호
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• pp.123-131
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• 2019

In recent years, a non-contact respiration and heart rates monitoring via IR-UWB radar has been paid much attention to in various applications - patient monitoring, occupancy detection, survivor exploring in disaster area, etc. In this paper, we address a novel approach of real time heart rate estimation using IR-UWB radar. We apply sine fitting and peak detection method for estimating respiration rate and heart rate, respectively. We also deploy two techniques to mitigate the error caused by wrong estimation of respiration rate: a moving average filter and finding the frequency of the highest occurrence. Experimental results show that the algorithm can estimate heart rate in real time when respiration rate is presumed to be estimated accurately.

• 한국멀티미디어학회논문지
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• 제20권9호
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• pp.1491-1501
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• 2017

In this paper, we propose a method to measure respiration rate by dividing the respiration related region in depth image using level set method. In the conventional method, the respiration related region was separated using the pre-defined region designated by the user. We separate the respiration related region using level set method combining shape prior knowledge. Median filter and clipping are performed as a preprocessing method for noise reduction in the depth image. As a feasibility test, respiration activity was recorded using depth camera in various environments with arm movements or body movements during breathing. Respiration activity was also measured simultaneously using a chest belt to verify the accuracy of calculated respiration rate. Experimental results show that our proposed method shows good performance for respiration rate estimation in various situation compared with the conventional method.

• 전자공학회논문지
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• 제49권9호
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• pp.49-54
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• 2012

본 논문에서는 IR-UWB 레이더 신호의 크기와 도달시간을 결합한 새로운 방법의 호흡속도추정 방법을 제안한다. 특히 이 논문에서는 분석을 통해서 인체의 흔들림이 호흡속도추정에 왜곡을 일으키지 않음을 증명한다. 분석을 바탕으로 레이더 신호의 크기 정보 신호와 도달시간 정보 신호의 컨볼루션 방법을 제안한다. 하드웨어 실험을 통한 분석을 통해서 호흡속도성분의 추출 능력이 기존의 추정 방법에 비해서 10dB 이상 향상됨을 보인다.

• 한국전자파학회논문지
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• 제28권10호
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• pp.802-809
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• 2017

본 논문에서는 IR-UWB 레이다 신호를 이용하여 무호흡 검출과 호흡수를 측정할 수 있는 방법을 제안한다. 제안한 방법에서는 무호흡 검출과 호흡수 측정을 동시에 지원하기 위해서 레이다 신호의 크기, 도래시간 및 선택된 주파수 대역에서의 전력 정보를 이용한다. 하드웨어 실험을 통해서 제안한 방법을 사용하여 정확한 호흡수 측정이 가능함을 보인다. 또한, 제안한 방법을 사용하여 무호흡과 호흡의 선택비가 최소 50 dB 이상이 됨을 보인다.

• 센서학회지
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• 제17권6호
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• pp.447-453
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• 2008

Respiration rate is one of the important vital signs. Photo-plethysmography (PPG) measurement especially on a finger has been widely used in pulse oximetry and also used in estimating respiration rate. It is well known that PPG contains respiration-induced intensity variation (RIIV) signal. However, the accuracy of finger PPG method has been controversial. We introduced a new technique of enhancing motion artifact by respiration. This was achieved simply by measuring PPG on the thorax. We examined the accuracy of these two PPG methods by comparing with two existing methods based on thoracic volume and nostril temperature changes. PPG sensing on finger tip, which is the most common site of measurement, produced 6.1 % error. On the other hand, our method of PPG sensing on the thorax achieved 0.4 % error which was a significant improvement. Finger PPG is sensitive to motion artifact and it is difficult to recover fully small respiratory signal buried in waveform dominated by absorption due to blood volume changes. Thorax PPG is poor to represent blood volumes changes since it contains substantial motion artifact due to respiration. Ironically, this inferior quality ensures higher accuracy in terms of respiration measurement. Extreme low-cost and small-sized LED/silicon detector and non-constrained reflection measurement provide a great candidate for respiration estimation in ubiquitous or personal health monitoring.

• 한국농촌건축학회논문집
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• 제26권3호
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• pp.1-9
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• 2024

This study aims to estimate the cover classification and carbon respiration of halophytes based on the issues of utilising blue carbon in recent context of climate change. To address the aims, the study classified halophytes(Triglochin maritimum L and Phragmites australis), Intertidal(non-vegetated tidal flats) and Supratidal(sandy tidal flats) to measure carbon respiration and classify cover. The results are revealed that first, the carbon respiration in vegetated areas was less than that in non-vegetated areas. Second, the cover classification could be divided into halophyte communities(Triglochin maritimum L, Phragmites australis), Intertidal and Supratidal by NDWI(Moisture Index, Normalized Difference Water Index) Third, the total carbon respiration of blue carbon was calculated to be -0.0121 Ton km² hr^-1 with halophyte communities at -0.0011 Ton km² hr^-1, Intertidal respiration at -0.0113 Ton km² hr^-1 and Supratidal respiration at 0.0003 Ton km² hr^-1. As this challenge is a fundamental study that calculates the quantitative net carbon storage based on the blue carbon-based marine ecosystem, contributing to firstly, measuring the carbon respiration of cordgrass communities, reed communities, and non-vegetated tidal flats, which are potential blue carbon candidates in the study area, to establish representative values for carbon respiration, secondly, verifying the reliability of cover classification of native halophytes extracted through image classification technology, and thirdly, challenging to create a thematic map of carbon respiration, calculating the area and carbon respiration for each classification category.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.334-343
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• 2014

In this paper, we suggest a method to improve the fusion of an accelerometer and gyro sensor by using a Kalman filter to produce a more high-quality respiration signal to supplement the weakness of using a single accelerometer. To evaluate our proposed algorithm's performance, we developed a chest belt-type module. We performed experiments consisting of aerobic exercise and muscular exercises with 10 subjects. We compared the derived respiration signal from the accelerometer with that from our algorithm using the standard respiration signal from the piezoelectric sensor in the time and frequency domains during the aerobic and muscular exercises. We also analyzed the time delay to verify the synchronization between the output and standard signals. We confirmed that our algorithm improved the respiratory rate's detection accuracy by 4.6% and 9.54% for the treadmill and leg press, respectively, which are dynamic. We also confirmed a small time delay of about 0.638 s on average. We determined that real-time monitoring of the respiration signal is possible. In conclusion, our suggested algorithm can acquire a more high-quality respiration signal in a dynamic exercise environment away from a limited static environment to provide safer and more effective exercises and improve exercise sustainability.

• Journal of Ecology and Environment
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• 제42권2호
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• pp.77-84
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• 2018

Background: For understanding and evaluating a more realistic and accurate assessment of ecosystem carbon balance related with environmental change or difference, it is necessary to analyze the various interrelationships between soil respiration and environmental factors. However, the soil temperature is mainly used for gap filling and estimation of soil respiration (Rs) under environmental change. Under the fact that changes in precipitation patterns due to climate change are expected, the effects of soil moisture content (SMC) on soil respiration have not been well studied relative to soil temperature. In this study, we attempt to analyze relationship between precipitation and soil respiration in temperate deciduous broad-leaved forest for 2 years in Gwangneung. Results: The average soil temperature (Ts) measured at a depth of 5 cm during the full study period was $12.0^{\circ}C$. The minimum value for monthly Ts was $-0.4^{\circ}C$ in February 2015 and $2.0^{\circ}C$ in January 2016. The maximum monthly Ts was $23.6^{\circ}C$ in August in both years. In 2015, annual precipitation was 823.4 mm and it was 1003.8 mm in 2016. The amount of precipitation increased by 21.9% in 2016 compared to 2015, but in 2015, it rained for 8 days more than in 2016. In 2015, the pattern of low precipitation was continuously shown, and there was a long dry period as well as a period of concentrated precipitation in 2016. 473.7 mm of precipitation, which accounted for about 51.8% of the precipitation during study period, was concentrated during summer (June to August) in 2016. The maximum values of daily Rs in both years were observed on the day when precipitation of 20 mm or more. From this, the maximum Rs value in 2015 was $784.3mg\;CO_2\;m^{-2}\;h^{-1}$ in July when 26.8 mm of daily precipitation was measured. The maximum was $913.6mg\;CO_2\;m^{-2}\;h^{-1}$ in August in 2016, when 23.8 mm of daily precipitation was measured. Rs on a rainy day was 1.5~1.6 times higher than it without precipitation. Consequently, the annual Rs in 2016 was about 12% higher than it was in 2015. It was shown a result of a 14% increase in summer precipitation from 2015. Conclusions: In this study, it was concluded that the precipitation pattern has a great effect on soil respiration. We confirmed that short-term but intense precipitation suppressed soil respiration due to a rapid increase in soil moisture, while sustained and adequate precipitation activated Rs. In especially, it is very important role on Rs in potential activating period such as summer high temperature season. Therefore, the accuracy of the calculated values by functional equation can be improved by considering the precipitation in addition to the soil temperature applied as the main factor for long-term prediction of soil respiration. In addition to this, we believe that the accuracy can be further improved by introducing an estimation equation based on seasonal temperature and soil moisture.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권10호
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• pp.733-740
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• 2004

In this paper, an improved algorithm for the extraction of respiration signal from the electrocardiogram (ECG) is proposed. The whole system consists of two-lead electrocardiogram acquisition (lead Ⅰ and Ⅱ), baseline fluctuation elimination, R-wave detection, adjustment of sudden change in R-wave area using moving average, and optimal lead selection. In order to solve the problem of previous algorithms for the ECG-derived respiration (EDR) signal acquisition, we proposed a method for the optimal lead selection. An optimal EDR signal among the three EDR signals derived from each lead (and arctangent of their ratio) is selected by estimating the instantaneous frequency using the Hilbert transform, and then choosing the signal with minimum variation of the instantaneous frequency. The proposed algorithm was tested on 15 subjects, and we could obtain satisfactory respiration signals that shows high correlation (r>0.9) with the signal acquired from the chest-belt respiration sensor.

• 대한의용생체공학회:의공학회지
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• 제34권3호
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• pp.105-110
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• 2013

Respiratory signal is one of the important physiological information indicating the status and function of the body. Recent studies have provided the possibility of being able to estimate the respiratory signal by using a change of PWV(pulse width variability), PRV(pulse rate variability) and PAV(pulse amplitude variability) in the PPG (photoplethysmography) signal during daily life. But, it is not clear whether the respiratory monitoring is possible even during sleep. Therefore, in this paper, we estimated the respiration from PWV, PRV and PAV of PPG signals during sleep. In addition, respiration rates of the estimated respiration signal were calculated through a time-frequency analysis, and errors between respiration rates calculated from each parameter and from reference signal were evaluated in terms of 1 sec, 10 sec and 1 min. As a result, it showed the errors in PWV(1s: $36.38{\pm}37.69$ mHz, 10s: $36.53{\pm}38.16$ mHz, 60s: $30.35{\pm}38.72$ mHz), in PRV(1s: $1.45{\pm}1.38$ mHz, 10s: $1.44{\pm}1.37$ mHz, 60s: $0.45{\pm}0.56$ mHz), and in PAV(1s: $1.05{\pm}0.81$ mHz, 10s: $1.05{\pm}0.79$ mHz, 60s: $0.56{\pm}0.93$ mHz). The errors in PRV and PAV are lower than that of PWV. Finally, we concluded that PRV and PAV are more effective than PWV in monitoring the respiration in daily life as well as during sleep.