• 한국학교보건학회지
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• 제34권2호
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• pp.115-122
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• 2021

Purpose: The purpose of this descriptive research is to identify how stress from Covid-19, health beliefs, and social support of college students affect health prevention. Methods: The subjects of the study were 128 university students, excluding health major students, at one university in D City. The survey was conducted from August 1 to 31, 2020. The survey questionnaire consists of 8 items on stress from COVID-19, 12 items adapted from a health belief measurement tool, 12 items from a social support measurement tool, and 11 items adapted from a tool that measures health preventive behaviors. The collected data were analyzed using the hierarchical multiple regression analysis method with SPSS 26.0. Results: In model 1, stress from COVID-19 was statistically significant (β=-.403, p=.003). Model 2 added four health belief factors into Model 1. Stress (β=-.419, p<.001), perceived severity (β=-.193, p=.030), and perceived barriers (β=-.182, p=.009) were statistically significant. In model 3, stress (β=-.413, p<.001), perceived barriers (β=-.147, p=.034), and social support (β=.194, p=.011) were statistically significant. The regression equation was significant (F=15.395, p=<.001) and the model's explanatory power was 53.1%. Conclusion: The results show that when college students had a high degree of health beliefs about COVID-19, the degree of health preventive behaviors was proportionally high. To make them practice preventive health behaviors, it is necessary to develop infection control education programs to improve health beliefs.

• Journal of Preventive Medicine and Public Health
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• 제10권1호
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• pp.44-51
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• 1977

In order to determine values for the body weight by height groups for Korean adults men who are fully grown up 4,028 (30-39 age-group ; 2,318, 40-49 age-group 1,340, and 50-59 age group : 370) apparently healthy males subjects were randomly selected for the measurement of body weight by height groups. 1) The avergae body height and weight of Korean adult men were $168.3{\pm}4.6cm$ and $63.4{\pm}7.1kg$ in 30-39 age group, $167.7{\pm}4.7cm$ and $63.4{\pm}7.4kg$ in 40-49 age group, and $167.3{\pm}5.2cm$ and $63.3{\pm}8.0kg$ in 50-59 age group. 2) A correlation coefficient of r=+0.52(P<0.001) between body height and weight was found in 30-39 age group of 2,318 subject, r=+0.48(P<0.001) in 40-49 of 1,340 and r=+0.53(P<0.001) in 50-59 of 370 with the aid of there coefficients of linear regression equation body weight and height were established for male as follow; for 30-39 age group, Y(weight in kg)=0.81X(height in cm)-73.02, 40-49 age group, Y(weight in kg)=0.74X(height in cm)-61.82, 50-59g age-group, Y(weight in kg)=0.82X(height in cm)-73.83. 3) With the aid of above listed various equation standard values for body weight by height group, with over weighing and under weighing values were established. 4) Standard bodyweight of Korean was lower than those of American, Japanese and several other formulas for ideal body weight.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1991년도 춘계학술대회
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• pp.18-21
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• 1991

In this paper, the effect of background grey levels on the visual perception of target image displayed on CRT monitor has been investigated. The purpose of this study is to investigate the efficacy of CRT monitor as a display medium of image information especially in medical imaging field. Three sets of experiments have been performed in this study; the first was to measure the luminance response of CRT monitor and to find the best fitting equation, and the second was the psychophysical experiment measuring the threshold grey level difference between the target image and the background required for visual discrimination for various background grey levels, and the third was to develop a visual model that is predictable of the threshold grey level difference measured in the psychophysical experiment. The result of psycophysical experiment shows that the visual perception performance is significantly degraded in the range of grey levels lower than 50, which is turned out due to the low luminance change of CRT monitor in this range while human eye has been adapted to relatively bright ambient illumination.

• 한국도로학회논문집
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• 제17권4호
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• pp.33-40
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• 2015

PURPOSES: Evaluation of the wind speed effect on the temperature drop of an asphalt mixture during construction, by using the transient heat transfer theory and dominant convective heat transfer coefficient model. METHODS: Finite difference method (FDM) is used to solve the transient heat transfer difference equation numerically for various wind speeds and initial temperature conditions. The Blasius convective heat transfer coefficient model is adapted to account for the effect of wind speed in the temperature predictions of the asphalt mixture, and the Beaufort number is used to select a reasonable wind speed for the analysis. As a function of time and depth, the temperature of the pavement structure is predicted and analyzed for the given initial conditions. RESULTS : The effect of wind speed on the temperature drop of asphalt mixture is found to be significant. It seems that wind speed is another parameter to be accounted for in the construction specifications for obtaining a better quality of the asphalt mixture. CONCLUSIONS: It is concluded that wind speed has a significant effect on the temperature drop of the asphalt layer. Although additional field observations have to be made to reflect the effect of wind speed on the construction specifications, it appears that wind speed is a dominant variable to be considered, in addition to the atmospheric temperature.

• 한국자동차공학회논문집
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• 제18권5호
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• pp.31-36
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• 2010

SAI(Secondary Air Injection) system has been studied widely as one of the promising countermeasure for reducing HC emission at cold start. In this paper, in order to find out the optimal position of SAI, computational thermal fluid analysis on exhaust system adapted SAI system is performed using commercial 3-D CFD code, CFX. The present results showed that SAI position strongly affected the uniformity of air distribution in front of catalyst. And also through the decision process of optimal position of SAI, new index, uniformity of air distribution($U_{\phi}$) is proposed to define it quantitively. Because $U_{\phi}$ is very simple equation and similar with flow uniformity, it is very easy to figure out the physical meaning and to apply it to practices. Finally, we applied the index $U_{\phi}$ to the decision process of the optimal position of SAI, so that we could get the clear comparison results.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.615-620
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• 2005

Vibration in Engine module could be reduced by introducing a balance shaft module which has one or more unbalanced rotors. The unbalanced rotor is unbalanced in one direction that act as a opposite direction of the inertia force or moment triggered by engine component so that the largest order factor in vibration is efficiently decreased The ability of balance shaft to reduce the order element of engine component is investigated by a vehicle testing that is focused on comparing the vibration with balance shaft to that of without balance shaft. One of the commonly adapted balance shaft is tested by modal scheme for indemnifying the dynamic characteristics and an, the modal information is used for a clue to design the balance shaft module. The essential equation deriving the design parameters of unbalanced rotor is also presented for two cases, 3 in-ling and 4 in-ling cylinder model. Finally, the overall design process is explained with flow chart.

• Journal of Advanced Research in Ocean Engineering
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• 제3권2호
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• pp.59-65
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• 2017

When an anchor is dropped into the sea, there exists a danger of collision on the pipeline and subsea cables in the seabed. This collision could cause huge environmental disasters and serious economic losses. In order to secure the safety of subsea structures such as pipelines and subsea cables from the external impact, it is necessary to estimate the exact external force through the anchor's terminal velocity on the water. FLUENT, a computational fluid dynamic program, was used to acquire the terminal velocity and drag coefficient computation. A half-symmetry condition was used in order to reduce the computational time and a moving deforming mesh technique also adapted to present hydrostatic pressure. The results were examined with the equation based on Newton's Second Law to check the error rate. In this study, three example cases were calculated by stockless anchors of 5.25 ton, 10.5 ton, and 15.4 ton, and for the onshore experiment dropped height was back calculated with the anchor's terminal velocity in the water.

• 공학교육연구
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• 제15권5호
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• pp.93-97
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• 2012

Most of ubiquitous computing devices such as stereo camera, ultrasonic sensor based MIT cricket system and other wireless sensor network devices are widely applied to the 2 Dimensional(2D) localization system in today. Because stereo camera cannot estimate the optimal location between moving node and beacon node in Wireless Personal Area Network(WPAN) under Non Line Of Sight(NLOS) environment, it is a great weakness point to the design of the 2D localization system in indoor environment. But the conventional 2D triangulation scheme that is adapted to the MIT cricket system cannot estimate the 3 Dimensional(3D) coordinate values for estimation of the optimal location of the moving node generally. Therefore, the 3D triangulation scheme based on the space segmentation in WPAN is suggested in this paper. The measuring data in the suggested scheme by computer simulation is compared with that of the geographic measuring data in the AutoCAD software system. The average error of coordinates values(x,y,z) of the moving node is calculated to 0.008m by the suggested scheme. From the results, it can be seen that the location correctness of the suggested scheme is very excellent for using the localization system in WPAN.

• 대한의용생체공학회:의공학회지
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• 제14권1호
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• pp.63-72
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• 1993

In this paper, the effect of background grey levels on the visual perception of target image displayed on CRT monitor has been investigated. The purpose of this study is to investigate the efficacy of CRT monitor as a display medium of image Information especially in medical imaging field. Tllree sets of experiments have been performed in this study : the first was to measure the luminance response of CRT monitor and to find the best fitting equation, and the second was the psychophysical experiment measuring the threshold grey level differences between the target image and the background required for visual discrimination (or various background grey levels, and the third was to develop a visual model that is predictable of the threshold grey level difference measured in the psychophysical experiment. The result of psycophysical experiment shows that the visual perception performance is significantly degraded in the range of grey levels lower than 50, which is turned out due to she low luminance change of CRT monitor in this range while human eye has been adapted lo relatively bright ambient illumination. And it Is also shown in the simulation study using the developed visual model that the dominant factor degrading the visual performance is the reflected light from the monitor surface by ambient light in general illumination condition.

• Earthquakes and Structures
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• 제11권4호
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• pp.723-740
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• 2016

Reinforced concrete corbels are generally used to transfer loads within a structural system, such as buildings, bridges, and facilities in general. They commonly present low aspect ratio, requiring an accurate model for shear strength prediction in order to promote flexural behavior. The model described here, originally developed for walls, was adapted for corbels. The model is based on a reinforced concrete panel, described by constitutive laws for concrete and steel and applied in a fixed direction. Equilibrium in the orthogonal direction to the shearing force allows for the estimation of the shear stress versus strain response. The original model yielded conservative results with important scatter, thus various modifications were implemented in order to improve strength predictions: 1) recalibration of the strut (crack) direction, capturing the absence of transverse reinforcement and axial load in most corbels, 2) inclusion of main (boundary) reinforcement in the equilibrium equation, capturing its participation in the mechanism, and 3) decrease in aspect ratio by considering the width of the loading plate in the formulation. To analyze the behavior of the theoretical model, a database of 109 specimens available in the literature was collected. The model yielded an average model-to-test shear strength ratio of 0.98 and a coefficient of variation of 0.16, showing also that most test variables are well captured with the model, and providing better results than the original model. The model strength prediction is compared with other models in the literature, resulting in one of the most accurate estimates.