• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.496-499
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• 2006

In this study, a practical method of shrinkage stress analysis on concrete slab in multi-story building is proposed, which considers both internal restraint and external restraint variation resulting from construction sequence. The shrinkage stress due to external restraint is obtained by multiplying relaxation coefficient to elastic shrinkage stress. The additional shrinkage stress due to internal restraint is obtained by residual strain of the elastic analysis. A verification example was analyzed and compared by the proposed method and commercial analysis program that is capable of time-dependent analysis of concrete. The results of 10-story example building show that the internal restraint of reinforcement increases the shrinkage stress considerably at the slabs under loose external restraint.

• Nuclear Engineering and Technology
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• v.39 no.1
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• pp.75-84
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• 2007

This paper presents a closed-form model for evaluating the restraint effect of pressure induced bending on the opening of a circumferential through-wall crack, which is considered plastic deformation behavior. Three-dimensional finite element analyses with different crack lengths, restraint conditions, pipe geometries, magnitudes of internal pressure, and tensile properties were used to investigate the influence of each parameter on the pressure-induced bending restraint on the crack opening displacement. From these investigations, an analytical model based on elastic-perfectly plastic material was developed in terms of the crack length, symmetric restraint length, mean radius to thickness ratio, axial stress corresponding to the internal pressure, and normalized crack opening displacement evaluated from a linear-elastic crack opening condition. Finite element analyses results demonstrate that the proposed analytical model reliably estimated the restraint effect of pressure-induced bending on the plastic crack opening of a circumferential through-wall crack and properly reflected the dependence on each parameter within the range over which the analytical expression was derived.

• Journal of Korean Academy of Nursing
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• v.31 no.1
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• pp.43-54
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• 2001

The purpose of this study was to investigate the relationship between health locus of control (HLOC) and the eating behaviors in obese high school girls. The sample consisted of 262 obese high school girls in Seoul and Kangwon-Do. The results of this study were as follows: 1. The average scores of HLOC were HLOC- Internal; 4.06, HLOC-External; 2.47, and HLOC-Chance; 2.15. 2. The average scores of eating behavior factors were Disinhibition ; 2.91, Hunger ; 2.73, Dietary Restraint ; 2.55. 3. The HLOC-Internal and eating behavior (dietary restraint, disinhibition and hunger) were correlated positively. The HLOC- Chance and hunger was correlated positively. But HLOC-Chance and other eating behavior factors (dietary restraint & disinhibition) were not correlated in the level of statistical significances. The HLOC-External and eating behavior (dietary restraint, disinhibition and hunger) were correlated positively. 4. There was not a significant difference in HLOC depending on the existence of an obese sibling. There were significant differences in HLOC-Internal and HLOC- External depending on the evaluation of one's body figure. 5. There were significant differences in disinhibition and hunger depending on the existence of obese sibling. Also, there were significant difference in dietary restraint according to self perception of who is obese or not (t=3.342, p=.001). This study has shown a correlation between HLOC and eating behavior. As a result of these findings, clinical and school nurses should be involved in management and counselling obese girls concerning individual health locus of control and eating behavior.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.9 s.252
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• pp.1134-1141
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• 2006

This paper presents the model for evaluating restraint effect of pressure induced bending (PIB) on the circumferential through-wall crack opening displacement (COD), which considers plastic behavior of crack. This study performed three-dimensional elastic-plastic finite element (FE) analyses for different crack angle, restraint length, pipe geometry, stress level, and material conditions, and evaluated the influence of each parameter on the PIB restraint effect on COD. Based on these evaluations and additional perfectly-plastic FE analyses, a closed-form model to evaluate the restraint effect of PIB on the plastic crack opening of circumferential through-wall crack, was proposed as functions of crack angle, restraint length, radius to thickness ratio, axial stress corresponding to an internal pressure, and normalized COD evaluated from linear-elastic crack opening condition.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.11
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• pp.1873-1880
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• 2001

The effects of restraint of pressure induced bending(PIB) on crack opening for circumferential through-wall crack in a pipe were investigated. In this study, the elastic and elastic-plastic finite element analyses were performed to evaluate crack opening displacement(COD) for various restraint conditions and crack size. The results showed the restraint of PIB decreased crack opening for a given crack size and tensile stress, and the decrease in crack opening was considerable for large crack and short restraint length. A1so, the effect was more significant in tole results of elastic-plastic analysis compared with in the elastic analysis results. In the elastic-plastic analysis results, tole restraint effect was increased with increasing applied tensile stress corresponding to internal pressure. Additionally, the restraint effect on COD was independent on the variation in pipe diameter and decreased with increasing pipe thickness, and It depended on not total restraint length but shorter restraint length for non-symmetrically restrained.

• KIEE International Transactions on Power Engineering
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• v.4A no.3
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• pp.146-151
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• 2004

The most widely used primary protection for the internal fault detection of the power transformer is current ratio differential relaying (CRDR) with harmonic restraint. However, the second harmonic component could be decreased by magnetizing inrush when there have been changes to the material of the iron core or its design methodology. The higher the capacitance of the high voltage status and underground distribution, the more the differential current includes the second harmonic during the occurrence of an internal fault. Therefore, the conventional second harmonic restraint CRDR must be modified. This paper proposes a numerical algorithm for enhanced power transformer protection. This algorithm enables a clear distinction regarding internal faults as well as magnetizing inrush and steady state. It does this by analyzing the RMS fluctuation of terminal voltage, instantaneous value of the differential current, RMS changes, harmonic component analysis of differential current, and analysis of flux-differential slope characteristics. Based on the results of testing with WatATP99 simulation data, the proposed algorithm demonstrated more rapid and reliable performance.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.275-279
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• 1996

In this study, the effect of external restraint on the thermal stresses and thermal cracking mode in mass concrete are analysed using the two major factors affecting external restraint such as the ratio of width go height of the placed structure (L/H) and the elastic modulus of base structure (E). For this parametric study, many cases with different values of L/H and Er are analysed by the FEM program and the co-relationship of the those major factors is examined. To evaluate the effect of external restraint on the thermal behavior of placing structure, internal restraint stress caused by temperature difference is subtracted from total thermal stress. In the case of small value of L/H or Er, it shows as internally restricted mode indicating maximum tensile stress in surface at early age, and the external restraint makes the possibility of thermal cracking higher. However, in the case of the large values of L/H and Er, the crack index at center is smaller than at surface due to the effect of external restraint. Thus, the initial location of the thermal crack is shifted from the surface to the center and the resulting crack is formed at later age.

• Child Health Nursing Research
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• v.9 no.2
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• pp.123-130
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• 2003

Purpose: The purpose of this study was to investigate the relationship between health locus of control(HLOC) and eating behavior in obese middle school girls. Method: The sample consisted of 170 obese middle school girls in Seoul. Result: 1. The average scores of HLOC were HLOC-Internal ; 4.11, HLOC-External ; 2.45, HLOC-Chance ; 2.09. 2. The average scores of eating behavior factors were Disinhibition ; 2.69, Dietary Restraint ; 2.67, Hunger ; 2.55. 3. The HLOC-Internal and eating behavior(dietary restraint and hunger) were correlated positively. The HLOC-Chance and disinhibition was correlated positively. But HLOC-Chance and dietary restraint was correlated negatively. The HLOC-External and eating behavior(dietary restraint, disinhibition and hunger) were correlated positively. 4. There was not a significant difference in HLOC depending on the demographic characteristics(grade, degree of obesity, father & mother's body shape, existence of obese sibling). There were significant differences in HLOC-Internal and HLOC-External according to thinking about oneself who is obese or not. 5. There was not a significant difference in eating behavior depending on the demographic characteristics(grade, degree of obesity, father & mother's body shape, existence of obese sibling, perception of oneself as a obese). Conclusion: This study has shown a correlation between HLOC and eating behavior. As a result of these findings, clinical and school nurses should be involved in management and counselling of obese girls concerning individual health locus of control and eating behavior.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.1
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• pp.132-139
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• 2005

The driving position of head restraints and the relative risk of neck injury were studied in the computer simulation. MADYMO human model with the detail neck model was used to define the magnitude and direction of internal forces acting on the cervical spine during rear-end impact and to determine the effect of the initial position of the occupant's head with respect to the head restraints. Maximum reaction forces were generated during the head contact to the restraint and relatively large forces were generated at each spinal components in lower cervical spine in proportion to backset and height distance increasement.

• Proceedings of the KWS Conference
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• 2001.05a
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• pp.165-167
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• 2001