• Tuberculosis and Respiratory Diseases
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• 제69권2호
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• pp.108-114
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• 2010

Background: The aim was to estimate the differences between pulmonary disability grades according to the spirometry reference equations (the Korean equation and the Morris equation). Methods: Spirometry was performed on 16,916 male and 1,353 female special examination for pneumoconiosis, in the period of 2007~2009. Changes in predictive values for forced expiratory volume in one second ($FEV_1$), forced vital capacity (FVC) and $FEV_1$/FVC and in disability grade were evaluated using both equations. Results: Mean FVCs for men and women were 4,218.7 mL and 2,801.5 mL in predictive values after the application of the Korean equation, and 3,763.9 mL and 2,395.6 mL after the Morris equation, respectively. Compared with the Morris equation, the Korean equation showed 10.8% and 14.5% of excesses for men and women (p<0.001). Mean $FEV_1s$ for men and women were 3,102.5 mL and 2,107.1 mL in the Korean equation, and 2,667.8 mL and 1,699.6 mL in the Morris equation, respectively. Compared with the Morris equation, the Korean equation showed 14.0% and 19.3% of excesses for men and women (p<0.001). Men and women who showed the changes of disability grades using the Korean equation in place of the Morris equation were 23.9% (4,052/16,916) and 22.9% (311/1,353) on FVC, and 23.1% (3,913/16,916) and 10.7% (145/1,353) on $FEV_1$. Conclusion: Applying different reference equations for spirometry has resulted in changes for disability grades in special examination for pneumoconiosis.

• Tuberculosis and Respiratory Diseases
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• 제60권2호
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• pp.215-220
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• 2006

연구 배경: 폐활량측정법 정상예측식이 한국인을 대상으로 개발되었다. 한국인 정상예측식을 실제 진료에 사용하기 위해서 그 동안 많이 사용하던 정상 예측식 중 하나인 Morris 예측식을 적용하였을 때와 한국인 예측식을 적용하였을 때 장애 양상 해석 및 질병 중증도 평가가 어떻게 달라지나 비교하고자 하였다. 방 법: 서울아산병원의 호흡기검사실에서 2004년도 11월 한 달간 폐활량측정법을 시행한 남자 926명과 여자 694명을 대상으로 하였다. 나이, 성, 키, 몸무게, 그리고 폐활량측정법으로 $FEV_1$ [forced expiratory volume in one second], FVC [forced vital capacity], $FEV_1/FVC$ 등을 구하였다. 한국인 예측식과 Morris 예측식을 사용하여 장애 양상 해석과 질병 중증도 평가를 하였고 그 차이를 비교하였다. 폐활량측정법 장애 양상은 $FEV_1/FVC$과 FVC 값에 따라서 정상, 제한성, 폐쇄성, 양상 미정 등으로 정의하였고 질병 중증도는 기류제한이 있는 환자는 $FEV_1$ 값에 따라서 기류제한이 없는 환자는 FVC값에 따라서 정의하였다. 결 과: Morris 예측식에서 한국인 예측식으로 바꾸어 적용하면 장애 양상 해석이 남자 환자의 경우 22.5% (208/926) 달라졌고 여자의 경우 24.8% (172/694) 달라졌다. 한국인 예측식을 적용하였을 때, 기류제한이 있는 환자의 경우 질병의 중증도가 남자에서 30.2% (114/378) 바뀌었고 여자에서 39.4% (37/94) 바뀌었다. 기류제한이 없는 환자의 경우는 질병의 중증도가 남자에서 27.9% (153/548) 바뀌었고 여자에서 30.2% (181/600) 바뀌었다. 결 론: 폐활량측정법 정상예측식이 바뀌면 장애 양상 해석과 질병 중증도 평가에 유의한 영향을 미칠 수 있다.

• 대한수학회보
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• 제54권6호
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• pp.2165-2182
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• 2017

Let G be a group and $\mathbb{C}$ the field of complex numbers. Suppose ${\sigma}:G{\rightarrow}G$ is an endomorphism satisfying ${{\sigma}}({{\sigma}}(x))=x$ for all x in G. In this paper, we first determine the central solution, f : G or $G{\times}G{\rightarrow}\mathbb{C}$, of the functional equation $f(xy)+f({\sigma}(y)x)=2f(x)+2f(y)$ for all $x,y{\in}G$, which is a variant of the quadratic functional equation. Using the central solution of this functional equation, we determine the general solution of the functional equation f(pr, qs) + f(sp, rq) = 2f(p, q) + 2f(r, s) for all $p,q,r,s{\in}G$, which is a variant of the equation f(pr, qs) + f(ps, qr) = 2f(p, q) + 2f(r, s) studied by Chung, Kannappan, Ng and Sahoo in [3] (see also [16]). Finally, we determine the solutions of this equation on the free groups generated by one element, the cyclic groups of order m, the symmetric groups of order m, and the dihedral groups of order 2m for $m{\geq}2$.

• 한국전산유체공학회지
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• 제13권3호
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• pp.35-43
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• 2008

A methodology for the simulation of compressible high Reynolds number flow over rigid and moving bodies on a structured Cartesian grid is described in this paper. The approach is based on a modified version of the Brinkman Penalization method. To avoid oscillations in the vicinity of the body and to simulate shcok-containing flows, a Weighted Essentially Non-Oscillatory scheme is used to discretize the spatial flux derivatives. For high Reynolds number viscous flow, two turbulence models of the two-equation Menter's SST URANS model and a two-equation Detached Eddy Simulation are implemented. Some simple flow examples are given to assess the accuracy of the technique. Finally, a moving grid capability is demonstrated.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 추계 학술대회논문집
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• pp.200-208
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• 2007

A methodology for the simulation of compressible high Reynolds number flow over rigid and moving bodies on a structured Cartesian grid is described in this paper. The approach is based on a modified version of the Brinkman Penalization method. To avoid oscillations in the vicinity of the body and to simulate shcok-containing flows, a Weighted Essentially Non-Oscillatory scheme is used to discretize the spatial flux derivatives. For high Reynolds number viscous flow, two turbulence models of the two-equation Menter's SST URANS model and a two-equation Detached Eddy Simulation are implemented. Some simple flow examples are given to assess the accuracy of the technique. Finally, a moving grid capability is demonstrated.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2004년도 한국우주과학회보 제13권2호
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• pp.290-292
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• 2004

Near-IR observations of the central few parsecs of our Galaxy from the HST/NICMOS have been analyzed to produce H, K photometry. We have cross-identified our photometry with the Keck high-resolution spectrometry of the central 0.5 pc of our galaxy to distinguish evolved late-type stars from early-type stars, and use late-type stars as tracer population. We perform several statistical tests to find the best fitting parameters of stellar density distribution and velocity dispersion models, then derive volume number densities and velocity dispersions. The volume number density distribution has power law index $1.55\~1.7$. We then derive the mass distribution in the Central region of our Galaxy using the Jeans equation.

• Journal of the Korean Physical Society
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• 제73권12호
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• pp.1800-1807
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• 2018

In this paper, we study the gravitational perturbation of traversable wormhole spacetime, especially the Morris-Thorne wormhole spacetime, by using the linearized theory of gravity. We restrict our interest to the first order term and ignore the higher order terms. We assume that the perturbation is axisymmetric. We also assume that the time dependence follows the Fourier decomposition and the angular dependence is expressed in terms of the Legendre functions. As a result, we derive the gravitational perturbation equation of traversable wormhole in terms of a single linear second-order differential equation. As a consequence, we could analyze the unstability of the spacetime with the effective potentials. Furthermore, we consider the interaction between the external gravitational perturbation and the exotic matter, constituting traversable wormholes and its effect on the stability of traversable wormholes.

• 대한한방내과학회지
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• 제26권3호
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• pp.587-595
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• 2005

Objectives : The object of this study was to evaluate repeatability of portable spirometry and to determine an appropriate equation for predicted value. Materials and Methods : The subjects were 76 men and 45 women recruited from among Kyunghee University oriental medical students. Portable spirometry was performed via the procedure recommended in ATS guidelines. Repeatability of spirometry was checked against ATS repeatability standards and NHLEP QC grade. Percentage of predicted value of non-smokers was calculated through a Caucasian population-based regression equation(by Morris et al.) and Korean population based regression equation(by Kim et al.). These were compared. Result : 91.7% of subjects matched repeatability standards of ATS and 95% of subjects got interpretable NHLEP QC grades of A, B, and C. Mean percentage of predicted value by Morris et al. were as follows: Mean of FVC% was 90.86, FEV1% was 96.66, FEV1/FVC% was 107.48. Mean percentage of predicted value by Kim et al. were as follows. Mean FVC% was 92.38, FEV1% was 89.77, FEV1/FVC% was 96.95. Conclusions : Results of this study show that more than 90% of subjects meet repeatability criteria. This supports a role for the portable spirometer as a primary oriental medical office tool. Further, results are a verify that they Korean population-based predicted value equation is a more appropriate standard than the Caucasian population-based one, but a still more accurate standard is needed for the Korean adult population.

• Tuberculosis and Respiratory Diseases
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• 제61권3호
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• pp.218-226
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• 2006

연구 배경: 폐용적과 폐확산능의 정상예측식은 국가나 인종 등에 영향을 받는 것으로 알려져 있으나 우리나라 성인 대상으로 한 정상예측식이 폐용적은 없고, 폐확산능의 정상예측식은 있으나 많이 사용하지 않고 있다. 이에 기존에 사용하고 있는 여러 정상예측식 중 우리나라 성인에 가장 적합한 식을 선정하고자 본 연구를 수행하였다. 방 법: 비흡연, 건강한 성인을 대상으로 한양대학교 구리병원에서 모집한 남자 30명, 여자 33명 그리고 서울아산병원에서 모집한 남자 27명, 여자 34명을 대상으로 하였다. 이 대상자의 키와 몸무게를 측정하였고 전신체적용적기록(whole body plethysmography)로 폐용적을 측정하였으며 단회호흡법(single breath mothod)를 이용하여 폐확산능을 측정하였다. 가장 적합한 정상예측식은 실측치와 예측치의 차이인 잔차의 합이 최소가 되는 식으로 선정하였다. 결 과: 전폐용량의 잔차의 합이 최소가 되는 정상예측식은 한양대병원에서 모집한 대상자의 경우 남자는 ECSC 식 (잔차의 평균: 0.04 L), 여자는 Crapo/Morris 식 (-1.04)이었고 서울아산병원에서 모집한 대상자의 경우 남자는 Goldman/Becklake식 (-2.35), 여자는 ECSC 식 (-4.49)이었다. 폐확산능은 잔차의 평균이 최소가 되는 식은 한양대병원 남자는 Roca 식 (잔차의 평균: -13.66 ml/min/mmHg, 여자는 박 등의 식 (25.08)이었고 서울아산병원 남녀는 모두 박 등의 식(남자: -1.65, 여자: -6.46)이었다.

• 유통과학연구
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• 제19권9호
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• pp.5-17
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• 2021

Purpose: As mobile devices are commonly used and contact-free services are widespread due to the COVID-19 pandemic in the recent distribution environment, this study suggests retail strategies for consumers using high-speed railways. To this end, we analyzed how consumer perception on technologies necessary for use of mobile apps is related to the attitude that drives consumers to continue using the app services. Research design, data and methodology: Based on the extended unified theory of technology acceptance and use of technology model by Venkatesh, Morris, Davis and Davis (2003), we added variables proposed by existing theories that studied the technology acceptance model from multiple perspectives and empirically analyzed the relationship between user satisfaction and use intention with structural equation modeling. Results: As expected, factors necessary for the use of app services such as performance expectancy, social influence, price value, facilitating conditions, security, and aesthetics had positive effects on user satisfaction, whereas the effect of effort expectancy on user satisfaction was rejected. And user satisfaction was found to have a significant effect on intention to use. Conclusions: The results provide implications that strategic retail management of the above factors can motivate passengers to continuously use high-speed railways.