• Korean Journal of Social Welfare
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• v.61 no.4
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• pp.333-354
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• 2009

This study decomposes the gender differences on poverty to explain the causes of the poverty gap between male- and female-headed households. In order to do this, we start from examining the extent of the poverty gap between maleand female-headed families and then conduct decomposition of poverty differences by gender using the Oaxaca method. This paper uses the (Urban) Family Budget Survey data from 1982 to 2008 and measures poverty using 50% of the median income poverty line. Major findings of this study are as follows: First, in 2008, the coefficient effect explains 70% or more of the total gender-poverty gap. Second, the trend of gender-poverty gap in the period of 1982~2008 shows that the poverty gap by gender increased in the 1980s', decreased in the 1990s', and a re-increased in 2000s'. Third, comparing the decomposition results in 1982, 1989, 1999, 2008, we found that the share of characteristic effect of the total gender poverty gap has been increased gradually over time. It means the characteristics of the female-headed households have become worse than those of the male-headed households in urban working families. At the same time, the still large coefficient effect suggests that the problems such as the discrimination against matriarchs or the lack of social support for them still play important roles among urban working families in Korea.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.192-192
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• 1999

• The Journal of the Korea Contents Association
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• v.20 no.4
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• pp.416-426
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• 2020

The purpose of this research is to explore the relationship between organizational cultural perception gap and organizational effectiveness. it has rarely been studied in the academia. The research of the organizational cultural perception gap provides entrepreneurs directions on how to manage a company. Since previous studies have been focused on cultural type or strength, this study aims to suggest managerial implication in detail by analyzing present-ideal gap. Furthermore, this study would discover how it is different according to a psychological mechanism. The empirical results of 134 employees showed that the organizational cultural perception gap (i.e. Clan) had a negative effect on job satisfaction and affective commitment. In order to reduce the negative effects of organizational cultural perception gap, it is necessary to reach an agreement with members on organizational culture, which is ideal for organizational level, and understanding the members' internal motivations is important for proper organizational management.

• Journal of Korean Library and Information Science Society
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• v.49 no.2
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• pp.179-199
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• 2018

The purpose of this study is to analyze the difference of economic condition of students, that is, the difference of basic information utilization ability stemming from education gap. First, we investigated information literacy for high school freshmen who can control the difference of information utilization education experience by school. In doing the research, 629 high school students in the metropolitan city were surveyed using web. we analyzed the educational gap between schools depending on their economic conditions and analyzed the correlation between education gap and basic information utilization ability. As a result, it was found that there is a very significant negative correlation between the ratio of students who get support for school expenses and basic information utilization ability. Second, regression equation was produced through regression analysis of information literacy regression to analyze the effect of educational gap on basic information literacy. In addition, it seeks to consider alternatives that can improve the inequality of information literacy which is derived from education gap.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.895-904
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• 2008

CWR (Continuous Welded Rail) may be broken when a temperature drop below the neutral temperature changes in axial force, causing tensile fracture and rail gap, in winter. Rail-breaks may lead to the damage of the rail and wheel by dynamic load, and the reduction of running safety if not detected before the passage of a train. In this study, the track and train coupled model with open gap for dynamic interaction analysis, is proposed. Linear track and train systems is coupled by the nonlinear Herzian contact spring and the complete system matrices of total track-train system is constructed. And the interaction phenomenon considering open gap, was defined by assigning the irregularity functions between the two sides of a gap. Time history analysis, which have an iteration scheme such as $Newmark-{\beta}$ method based on Modified Newton-Raphson methods, was performed to solve the nonlinear equation. Finally, numerical studies are performed to assess the effect of various parameters of system, apply to various speeds, open gap size and the support stiffness of rail.

• Carbon letters
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• v.9 no.2
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• pp.131-136
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• 2008

In order to investigate the effect of doping C, N, B and F elements on $TiO_2$ for reducing the band gap, the heat treatment of $TiO_2$ was carried out with tetraethylammonium tetrafluoroborate. Through XRD and XPS analysis, the C, N, B and F doped anatase $TiO_2$ was confirmed. According to the increase of temperature during treatment, the particle size was increased due to aggregation of $TiO_2$ with elements (B, C, N and F). To investigate the capacity of photocatalyst for degradation of dye under solar light, the degradation of acridine orange and methylene blue was conducted. The degradation of dyes was carried out successfully under solar light indicating the effect of doping elements (B, C, N and F) on $TiO_2$ for reducing the band gap effectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.7
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• pp.495-505
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• 2009

A two-dimensional circular cylinder freely falling in a channel has been simulated by using immersed boundary - lattice Boltzmann method (IB-LBM) in order to analyze the characteristics of motion originated by the interaction between the fluid flow and the cylinder. The wide range of the solid/fluid density ratio has been considered to identify the effect of the solid/fluid density ratio on the motion characteristics such as the falling time, the transverse force and the trajectory in the streamwise and transverse directions. In addition, the effect of the gap between the cylinder and the wall on the motion of a two-dimensional freely falling circular cylinder has been revealed by taking into account a various range of the gap size. As the cylinder is close to the wall at the initial dropping position, vortex shedding in the wake occurs early since the shear flow formed in the spacing between the cylinder and the wall drives flow instabilities from the initial stage of freely falling. In order to consider the characteristics of transverse motion of the cylinder in the initial stage of freely falling, quantitative information about the cylinder motion variables such as the transverse force, trajectory and settling time has been investigate.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.50-57
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• 2010

Various installation faults may lie in fasteners in the construction of a direct-fixation track by the top-down method. At an extreme, they may cause excessive interaction between the train and track, compromise the running safety of the train, and cause damage to the track components. Therefore, the faults need to be kept within the allowable level through an investigation of their effects on the interactions between the train and track. In this study, the vertical dynamic stiffness of fasteners in installation faults was measured based on the dynamic stiffness test by means of an experimental apparatus that was devised to feasibly reproduce gap faults. This study proposes an effective analytical model for a train-track interaction system in which most elements, except the nonlinear wheel-rail contact and some components that behave bi-linearly, exhibit linear behavior. To investigate the effect of the behavior of fasteners in gap faults in a direct-fixation track on the vehicle and track, vehicle-track interaction analyses were carried out, targeting key review parameters such as the wheel load reduction factor, vertical rail displacement, rail bending stress, and mean stress of the elastomer. From the results, it was noted that the gap faults in the concrete bearing surface of a direct-fixation track need to be limited for the sake of the long-term durability of the elastomer than for the running safety of the train or the structural safety of the track.

• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.258-270
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• 2020

A new task of using the Jacobian-Free-Newton-Krylov (JFNK) method for the PWR core transient simulations involving neutronics, thermal hydraulics and mechanics is conducted. For the transient scenario of PWR, normally the Picard iteration of the coupled coarse-mesh nodal equations and parallel channel TH equations is performed to get the transient solution. In order to solve the coupled equations faster and more stable, the Newton Krylov (NK) method based on the explicit matrix was studied. However, the NK method is hard to be extended to the cases with more physics phenomenon coupled, thus the JFNK based iteration scheme is developed for the nodal method and parallel-channel TH method. The local gap conductance is sensitive to the gap width and will influence the temperature distribution in the fuel rod significantly. To further consider the local gap conductance during the transient scenario, a 1D mechanics model is coupled into the JFNK scheme to account for the fuel thermal expansion effect. To improve the efficiency, the physics-based precondition and scaling technique are developed for the JFNK iteration. Numerical tests show good convergence behavior of the iterations and demonstrate the influence of the fuel thermal expansion effect during the rod ejection problems.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.9
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• pp.822-829
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• 2002

This paper deals with the distribution characteristics of the current density and axial magnetic flux density for each slits made on the contact electrode in the vacuum interrupter with axial magnetic field type using 3-dimension finite element analysis. It has been known that the presence of an axial magnetic field parallel to the current flow in the arc plasma can increase the high current breaking capacity of vacuum interrupter by carrying out the arc plasma from constricted mode to diffusion mode. The axial magnetic field is created of itself by current flow in the segments of coil electrode behind the contact electrode. The analyzed results show that if the slits are made in the contact electrode, they can increase the current density and axial magnetic flux density in the contact electrode surface and at the gap distance, which is due to decrease the effect of eddy currents flowing in the contact electrode. The phase shift due to eddy currents, defined 3s time difference between the maximum value of current and axial magnetic field, is decreased still more by increasing the number of slits made in the contact electrode at the center point of gap distance. These results demonstrate that 3-dimension finite element analysis has a great deal of merits in the development and evaluation of new electrode at the design of vacuum interrupter.