• 대한의용생체공학회:의공학회지
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• 제43권6호
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• pp.399-408
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• 2022

Because arrhythmia occurs irregularly, it should be examined for at least 24 hours for accurate diagnosis. For this reason, this paper developed firmware software for arrhythmia detection and prevented consumption of temporal and human resources and enabled continuous management and early diagnosis. Prior to the experiment, the interval between the R peaks of the QRS Complex was calculated using the Pan-Tompkins algorithm. The developed firmware software designed and implemented an algorithm to detect arrhythmia such as tachycardia, bradycardia, ventricular tachycardia, persistent tachycardia, and non-persistent tachycardia, and a data transmission format to monitor the collected data based on BLE. As a result of the experiment, arrhythmia was found in real time according to the change in BPM as designed in this paper. And the data quality for BLE communication was verified by comparing the sensor's serial communication value with the Android application reception value. In the future, wearable devices for real-time arrhythmia detection will be lightweight and developed firmware software will be applied.

• Journal of Yeungnam Medical Science
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• 제18권1호
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• pp.39-50
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• 2001

본 연구는 여러 가지 질병의 원인을 규명하는데 있어서 자율신경계 역할의 중요성을 인식하여 심전도 및 호흡신호의 변이를 이용하여 자율신경계를 감시할 수 있는 시스템을 개발하였다. 본 연구에서 제작된 증폭기에서는 트랜스를 사용하여 교류전원으로부터 환자를 격리시키고, 30 KHz의 고주파를 이용하여 임피던스법에 의한 호흡신호를 심전도와 동시에 처리할 수 있도록 하였으며, 아울러 서로의 채널에 대한 혼신의 영향을 최소화하도록 회로를 설계하였다. 시뮬레이터에 의한 테스트 결과에서 입력 조건에 따라 증폭기의 출력에 나타나는 시간 간격이 일치하게 나타나는 것을 확인하였다. 또 실제 서로 다른 조건을 가진 세 부류의 임상 환자의 심전도에서 R-R interval 및 호흡신호를 측정하여 추출할 수 있었다. 기존에는 주로 생체 신호 파라미터를 각각 측정하여 그 결과를 추출하였으나 본 연구에서는 R-R interval과 respiration의 파라미터를 통합하여 데이터를 수집, 처리함으로써 환자로부터 얻은 데이터를 임상 응용에 보다 효과적으로 적용할 수 있게 되었다. 따라서 향후 개발된 시스템의 보완을 통해 환자에 직접 적용하여 자율신경계 장애 환자에 대한 감시장치로 활용하고자 한다.

• 한국전자통신학회논문지
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• 제15권1호
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• pp.191-198
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• 2020

본 연구는 ECG 신호를 이용하여 AR/VR 장치 사용 중에 발생할 수 있는 스트레스와 심장 상태에 따른 위험 예측을 위한 실시간 분석 시스템을 개발하였다. 제안 방법에는 ECG 신호의 R-R 간격을 이용한 HRV, BPM 측정법과 선행연구를 이용하여, 2차원 공간의 대치방법을 통해 실시간 진단방법을 제안하였다. 5분단 위로 ECG 데이터를 분석하고 자율신경계 진단 결과로 도출했다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.554-559
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• 2005

It seems to be dangerous to use a cellular phone while driving since it increases driver's mental stress and makes driver's reaction time slow. This study is to investigate driver's psycho-physiological responses on mobile telephoning while driving. Among the three experimental factors (mobile-phone types, message IODs over mobile-phone, road types), only the message IODs over mobile-phone changed R-R intervals of electrocardiograph significantly. This result suggests that the regulations on the mobile telephoning while driving be changed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1702-1707
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• 2007

The reduction of pipe-thickness induced by flow accelerated corrosion (FAC) is one of the most serious problems on the maintenance of piping system in nuclear power plants (NNP). If the thickness of a pipe component is reduced below the critical level, it cannot sustain pressure and consequently results in leakage or rupture. For this reason, wall thinning by FAC has been inspected in secondary side piping systems in NPPs. In this research Round Robin Test (RRT) was conducted to verify confidence of wall thinning measurement system in NPP. 12 inspectors from 3 companies participated and 23 specimens were used according to standard practice in RRT. The gage R&R analysis was introduced in regard to repeatability and reproducibility that are affected to measurement system errors. Confidence intervals of thickness measurement system were obtained.

• 대한수학회보
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• 제51권6호
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• pp.1829-1839
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• 2014

Let (${\Omega}$, $\mathcal{S}$, ${\mu}$) be a probabilistic measure space, ${\varepsilon}{\in}\mathbb{R}$, ${\delta}{\geq}0$, p > 0 be given numbers and let $P{\subset}\mathbb{R}$ be an open interval. We consider a class of functions $f:P{\rightarrow}\mathbb{R}$, satisfying the inequality $$f(EX){\leq}E(f{\circ}X)+{\varepsilon}E({\mid}X-EX{\mid}^p)+{\delta}$$ for each $\mathcal{S}$-measurable simple function $X:{\Omega}{\rightarrow}P$. We show that if additionally the set of values of ${\mu}$ is equal to [0, 1] then $f:P{\rightarrow}\mathbb{R}$ satisfies the above condition if and only if $$f(tx+(1-t)y){\leq}tf(x)+(1-t)f(y)+{\varepsilon}[(1-t)^pt+t^p(1-t)]{\mid}x-y{\mid}^p+{\delta}$$ for $x,y{\in}P$, $t{\in}[0,1]$. We also prove some basic properties of such functions, e.g. the existence of subdifferentials, Hermite-Hadamard inequality.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.426-429
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• 2008

In this study, we propose the calibration algorithm for the solar channel (550 ${\sim}$ 900 nm) of MTSAT 1R which is the Japanese geostationary satellite launched on 26 Feb. 2005 and located at $140^{\circ}E$. We developed a method utilizing MODIS-derived BRDFs for the solar channel calibration over the bright desert area. Targets are selected based on the desert's brightness, spatial uniformity, temporal stability and spectral stability. The 6S model has been incorporated to account for directional effects of the surface using MODIS-derived BRDF parameters within the spectral interval in interest. Results based on the analysis for the period from November 2007 to June 2008 suggest that MTSAT-1R solar channel measurements have a low bias within 5%.

• Korean Journal of Mathematics
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• 제5권1호
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• pp.55-60
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• 1997

A continuum structure function(CSF) is a non-decreasing mapping from the unit hypercube to the unit interval. The reliability importance of component $i$ in a CSF at system level ${\alpha}$, $R_i({\alpha})$) say, is zero if and only if component $i$ is almost irrelevant to the system at level ${\alpha}$. A condition to check whether a component is almost irrelevant to the system is presented. It is shown that $R^{(m)}_i({\alpha}){\rightarrow}R_i({\alpha})$ uniformly as $m{\rightarrow}{\infty}$ where each $R^{(m)}_i({\alpha})$ is readily calculated.

• 전자통신동향분석
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• 제36권4호
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• pp.23-33
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• 2021

Wireless communication for train control is an active research field. The World Railway Federation in Europe developed GSM-R, which integrates the GSM-based voice call standard and train control signals. To provide advanced railway services, the LTE-R wireless communication system was developed in Korea for passenger services and wireless image information required by the railroad industry. Recently, direct communication technology for autonomous train driving has been studied to decrease the driving interval, and research is being conducted on a hyperloop train control system that runs at a maximum speed of 1,220km/h in a subvacuum environment of 0.001 atmosphere. In this paper, we summarize the trends in wireless communication technologies used for GSM-R/LTE-R railway systems. For future wireless communication in railway systems, we discuss autonomous train driving and the hyperloop railway control system, define wireless communication technology, and discuss trends in domestic and foreign technologies.

• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1771-1778
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• 2013

For the excited states of a hydrogen molecule up to n = 3 active spaces, potential energy curves (PECs) are obtained for values of the internuclear distance R in the interval [0.5, 10] a.u. within an accuracy of $1{\times}10^{-4}$ a.u. (Hartree) compared to the accurate PECs of Kolos, Wolniewicz, and their collaborators by using the multi-reference configuration-interaction method and Kaufmann's Rydberg basis functions. It is found that the accuracy of the PECs can be further improved beyond $1{\times}10^{-4}$ a.u. for that R interval by including the Rydberg basis functions with angular momentum quantum numbers higher than l = 4.