• Journal of Korean Biological Nursing Science
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• 제25권3호
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• pp.215-227
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• 2023

Purpose: The aim of this study was to develop a mobile app-based musculoskeletal exercise program (AMSEP) for operating room (OR) nurses and evaluate its effects on self-efficacy, the flexibility of the shoulders, lower back, and legs, and musculoskeletal symptoms and fatigue. Methods: The AMSEP was developed based on the information-motivation-behavioral skill model. In total, 48 OR nurses were recruited at a university hospital in Korea and divided into an experimental group (n=24) and a control group (n=24), matched for career experience in the OR. The experimental group participated in the AMSEP, while the control group received a booklet regarding musculoskeletal exercise. Results: The experimental group showed significant increases in self-efficacy (t = -2.77, p = .008) and flexibility of the right shoulder (t = -4.08, p < .001), left shoulder (t = -3.28, p = .002), lower back (t = -3.75, p < .001), and legs (t = -3.96, p < .001) compared to the control group. Musculoskeletal symptoms (t = 2.75, p = .008), and fatigue (Z = -1.98, p = .048) significantly decreased in the experimental group compared to the control group. Conclusion: Our findings indicate that the AMSEP for OR nurses provided information on the prevention of musculoskeletal disorders and methods of exercise, as well as an opportunity for continued exercise performance through self-management. The AMSEP was easily accessible and effective in increasing self-efficacy and flexibility and reducing musculoskeletal symptoms and fatigue.

• Investigative Magnetic Resonance Imaging
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• 제23권1호
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• pp.38-45
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• 2019

Purpose: To demonstrate the high-resolution numerical simulation of the respiration-induced dynamic $B_0$ shift in the head using generalized susceptibility voxel convolution (gSVC). Materials and Methods: Previous dynamic $B_0$ simulation research has been limited to low-resolution numerical models due to the large computational demands of conventional Fourier-based $B_0$ calculation methods. Here, we show that a recently-proposed gSVC method can simulate dynamic $B_0$ maps from a realistic breathing human body model with high spatiotemporal resolution in a time-efficient manner. For a human body model, we used the Extended Cardiac And Torso (XCAT) phantom originally developed for computed tomography. The spatial resolution (voxel size) was kept isotropic and varied from 1 to 10 mm. We calculated $B_0$ maps in the brain of the model at 10 equally spaced points in a respiration cycle and analyzed the spatial gradients of each of them. The results were compared with experimental measurements in the literature. Results: The simulation predicted a maximum temporal variation of the $B_0$ shift in the brain of about 7 Hz at 7T. The magnitudes of the respiration-induced $B_0$ gradient in the x (right/left), y (anterior/posterior), and z (head/feet) directions determined by volumetric linear fitting, were < 0.01 Hz/cm, 0.18 Hz/cm, and 0.26 Hz/cm, respectively. These compared favorably with previous reports. We found that simulation voxel sizes greater than 5 mm can produce unreliable results. Conclusion: We have presented an efficient simulation framework for respiration-induced $B_0$ variation in the head. The method can be used to predict $B_0$ shifts with high spatiotemporal resolution under different breathing conditions and aid in the design of dynamic $B_0$ compensation strategies.

• 컴퓨터교육학회논문지
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• 제16권3호
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• pp.49-60
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• 2013

본 연구는 블렌디드 이러닝이 대학의 강의실 위주의 수업에서 효과성을 향상시킬 수 있는지를 검증하고자 하였다. 먼저, 수업 사례를 분석하여 블렌디드 이러닝 운영방식으로 CbE(Class based E-learning)와 EbC(E-learning based Class) 방식을 도출하고, 수업구조로 Z형(Zigzag model)과 H형(Ladder model)을 정의하였다. 연구의 목적을 달성하기 위하여 A대학의 "엑셀실무" 과목에 CbE 방식의 H형 블렌디드 이러닝을 운영하였다. 집단은 사이버강의 학습참여비율의 50%이상인 집단(그룹 1)과 그렇지 않은 집단(그룹 2)으로 나누고, 자료의 분석은 $x^2$-검정, t -검정으로 학업 성취도를 비교하였다. 사이버강의 학습참여비율과 합격여부의 관계를 규명하기 위해 로지스틱 회귀분석을 실시하였다. 검정 결과, 그룹 1이 학업 성취도에서 통계적으로 유의하게 높게 나타났다. 로지스틱 회귀분석 결과에서 사이버강의 학습참여비율은 합격여부를 예측하는 유의미한 변인으로 규명됨에 따라, 블렌디드 이러닝의 효과성이 확증되었다. 연구 결과, H형 블렌디드 이러닝은 강의실 수업의 단점을 보완하여 학업 성취도와 학습 만족도를 향상시키고, 학습자가 블렌디드 이러닝 수업 방식에 대해 긍정적인 인식을 갖도록 한 것으로 나타났다. 끝으로 성공적으로 블렌디드 이러닝을 운영하기 위한 전략과 대학에서의 활성화 방안에 대해 제언하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1887-1889
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• 2002

One of the most frequent sources of the accident is metal contaminant in GIS. This paper deals with the characteristics of breakdown voltage of metallic particles using electrodes of various epoxy coating thickness. As experimental results, breakdown voltage of the thickly coated electrode is higher than that of thinly coated electrode. It is considered that resistance of the epoxy coating impedes the development of pre-discharges in the gas.

• 유공압시스템학회논문집
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• 제8권3호
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• pp.21-26
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• 2011

Nonlinear seal friction in pneumatic cylinders can impede the performance of pneumatic systems designed for high precision positioning with favorable high speed actuation. The behaviour of an elastomeric piston seals in high speed pneumatic cylinders is analyzed by nonlinear finite element analysis using ABAQUS. The contact pressures, stress and strain distributions and frictional forces of the squeeze type piston seal are simulated with variation of the seal radial installed interference, the operating pressures, friction coefficients and piston rod velocities. The nonlinear finite element model of the squeeze type piston seal is used to predict deformation of a seal, friction force and contact pressure distributions.

• Communications for Statistical Applications and Methods
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• 제25권5호
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• pp.545-557
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• 2018

The inclusion of covariates in the model often affects not only the estimates of meaningful variables of interest but also its statistical significance. Such gap between statistical and subject-matter significance is a critical issue in huge sample studies. A popular huge sample study, the sample cohort data from Korean National Health Insurance Service, showed such gap of significance in the inference for the effect of obesity on cause of mortality, requiring careful consideration. In this regard, this paper proposes a sample size calibration method based on a Monte Carlo t (or z)-test approach without Monte Carlo simulation, and also proposes a test procedure for subject-matter significance using this calibration method in order to complement the deflated p-value in the huge sample size. Our calibration method shows no subject-matter significance of the obesity paradox regardless of race, sex, and age groups, unlike traditional statistical suggestions based on p-values.

• 소성∙가공
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• 제15권2호
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• pp.143-147
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• 2006

Effect of processing condition on the hot extrusion of Al-Zn-Mg-Sc alloy was investigated. For this purpose, hot compression test and FE-simulation were conducted via Thermecmaster-Z and DEFORM-3D, respectively. The microstructure evolution during hot extrusion and post heat-treatment was investigated and deformation mechanisms were analyzed by constructing processing map. FE-simulation results show that the temperature difference between container and billet has considerable influence on the final shape of extruded T-shape bar. The relation between applied load and processing time was predicted by the FE-analysis as well as punch speed vs. stroke chart.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.202-205
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• 2005

Effect of processing condition on the hot extrusion of Al-Zn-Mg-Sc alloy was investigated. For this purpose, hot compression test and FE-simulation were conducted via Thermecmasteer-Z and DEFORM-3D, respectively. The microstructure evolution during hot extrusion and post heat-treatment was investigated and deformation mechanisms were analyzed by constructing processing map. FE-simulation results show that the temperature difference between container and billet has considerable influence on the final shape of extruded T-shape bar. The relation between applied load and processing time was predicted by the FE-analysis as well as punch speed vs. stroke chart.

• 유공압시스템학회:학술대회논문집
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• 유공압시스템학회 2010년도 춘계학술대회
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• pp.99-104
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• 2010

Nonlinear seal friction in pneumatic cylinders can impede the performance of pneumatic systems designed for high precision positioning with favorable high speed actuation. The behaviour of an elastomeric piston seal in high speed pneumatic cylinders is analysed by nonlinear finite element analysis using ABAQUS. The contact pressures, stress and strain distributions and frictional forces of the piston seal are simulated with variation of interference fits, supply pressures, friction coefficients and piston rod velocities. The nonlinear finite element model of the piston seal is used to predict deformation of a seal, friction force and contact pressure distributions.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 Proceedings of the 4th Korea-China Joint Workshop on Nuclear Waste Management
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• pp.1-11
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• 2004

PAN-4A composite ion exchanger was more selective for Sr ion than other cations and PAN-KCoFC composite ion exchanger has much higher ion exchange capacity for Cs ion than other cations. The ion exchange capacities obtained from Dubinin-Polanyi equation were 3.93 meq/g for Sr ion and 1.50 meq/g for Cs ion using PAN-4A and PAN-KCoFC ion exchangers, respectively. The modified Dubinin-Polanyi model fit the experimental data accurately in multi-component system. The effective surface diffusivities $(D_{s, cff})$ for Sr and Cs ions of PAN-4A and PAN-KCoFC ion exchangers were slightly increased with the different particle sizes.