• Title/Summary/Keyword: wave equation analysis

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The Effect of Maternal Positive Parenting Attitudes on School Adjustment among Multi-cultural Adolescents in Korea: Mediating Effect of Ego-resiliency (다문화가정 어머니의 긍정적 양육태도가 청소년의 학교적응에 미치는 영향: 자아탄력성의 매개효과)

  • Mok, So Ri;Suh, Bo Lim;Jeong, Jae Kyeong;Kang, Min Ju
    • Human Ecology Research
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    • v.57 no.3
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    • pp.341-352
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    • 2019
  • This study examined the effect of maternal positive parenting attitudes on school adjustment among multi-cultural adolescents in Korea and investigated if multi-cultural adolescents' ego-resiliency mediates the relationship between maternal positive parenting attitudes and school adjustment. We used panel data from the fifth wave (2015) of the Multicultural Adolescents Panel Study (MAPS) collected by the National Youth Policy Institute. Participants were 1,297 multi-cultural adolescents (639 boys, 658 girls) who are second-year middle school students and have foreign mothers. SPSS 25.0 performed descriptive statistical analysis and correlation analysis. The structural equation model (SEM) was estimated with Mplus 5.12. The results of this study were as follows. First, a higher level of maternal positive parenting attitudes were related to higher level of ego-resiliency and school adjustment for multi-cultural adolescents. Second, maternal positive parenting attitudes had an indirect effect on school adjustment for multi-cultural adolescents via ego-resiliency. The results of this study indicate that maternal positive parenting behaviors would help improve the school adjustment of multi-cultural adolescents by increasing the level of ego-resiliency. In addition, the results of this study suggest that improving ego-resiliency for multi-cultural adolescents can be an effective method to help in school adjustment, as well as education for maternal parenting attitude.

Potential Flow Analysis for a Ship with a Flow Control Plate near the Stern (선미부에 유동제어판을 부착한 선박에 대한 포텐셜 유동해석)

  • Choi, Hee-Jong;Chun, Ho-Hwan;Yoon, Hyun-Sik;Lee, In-Won;Park, Dong-Woo;Kim, Don-Jean
    • Journal of the Society of Naval Architects of Korea
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    • v.46 no.6
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    • pp.587-594
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    • 2009
  • In the paper the effect of a stern-plate attached to a ship was taken into account. The relationship between the trim angle of a ship and the wave-resistance coefficient induced by the a stern-plate was studied using the potential flow analysis method. Numerical algorithm was described using the panel method and the vortex lattice method(VLM) to simulate the flow phenomena around a ship. The non-linearity of the free surface boundary conditions were considered using the iterative method and the IGE-GMRES(Incomplete Gaussian Elimination-The Generalized Minimal RESidual) algorithm was adopted to solve the linear equation at each iterative step. Numerical calculations were carried out to investigate the validity of the adopted algorithm using KCS(KRISO 3600 TEU Container) hull. Possible cases for attachment of the plate were checked. The results showed that the numerical algorithm could be physically appropriate.

A Development of Method for Surface and Subsurface Runoff Analysis in Urban Composite Watershed (I) - Theory and Development of Module - (대도시 복합유역의 지표 및 지표하 유출해석기법 개발 (I)- 이론 및 모듈의 개발 -)

  • Kwak, Chang-Jae;Lee, Jae-Joon
    • Journal of Korea Water Resources Association
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    • v.45 no.1
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    • pp.39-52
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    • 2012
  • Surface-subsurface interactions are an intrinsic component of the hydrologic response within a watershed. In general, these interactions are considered to be one of the most difficult areas of the discipline, particularly for the modeler who intends simulate the dynamic relations between these two major domains of the hydrological cycle. In essence, one major complexity is the spatial and temporal variations in the dynamically interacting system behavior. The proper simulation of these variations requires the need for providing an appropriate coupling mechanism between the surface and subsurface components of the system. In this study, an approach for modelling surface-subsurface flow and transport in a fully intergrated way is presented. The model uses the 2-dimensional diffusion wave equation for sheet surface water flow, and the Boussinesq equation with the Darcy's law and Dupuit-Forchheimer's assumption for variably saturated subsurface water flow. The coupled system of equations governing surface and subsurface flows is discretized using the finite volume method with central differencing in space and the Crank-Nicolson method in time. The interactions between surface and subsurface flows are considered mass balance based on the continuity conditions of pressure head and exchange flux. The major module consists of four sub-module (SUBFA, SFA, IA and NS module) is developed.

Precariousness and Happiness of South Korean Young Adults: The Mediating Effects of Uncertainty and Disempowerment (한국 청년의 삶의 불안정성(precariousness)과 행복: 불확실성과 통제권한 부재의 매개효과)

  • Han, Seungheon;Yim, Dahye;Kang, Minah
    • 한국사회정책
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    • v.24 no.2
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    • pp.87-126
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    • 2017
  • This study aims to examine the level of precariousness among young adults in South Korea and analyze the factors affecting their subjective well-being by adopting the three forms of precariousness suggested by Rodgers(1989) such as lack of resource, uncertainty and disempowerment as its analytical framework. Structural Equation Model was used for analyzing the path model of self-rated health, income level and social support(three forms of resource) affecting subjective wellbeing through uncertainty and disempowerment. Study population include young adults aged between 19 to 34 with a sample size of 415 using data of the 8th wave of the Korean General Social Survey(KGSS), 2010. Study population is divided into lower-age group (aged between 19-26) and upper-age group (aged between 27-34) in order to examine the differences between age groups by using Multiple Group Analysis. Study results show that three forms of resources, uncertainty and disempowerment had direct effect on the subjective well-being of South Korean young adults and disempowerment had the most significant effect among the factors. In addition, self-rated health and income level had indirect effect on subjective well-being through both uncertainty and disempowerment while social support had indirect effect on subjective well-being only through disempowerment. Results from the Multiple Group Analysis indicate that among the two age groups, income level only has a significant effect on subjective well-being in the upper-age group. In addition, disempowerment had greater effect on subjective wellbeing among upper-age group than the lower-age group. Based on the study results, this paper suggested policy implications and discussion for further research.

The Effect of Economic Status of Single-Parent famillies on Children's School Adjustment Mediating effects of neglectful rearing attitudes and mental health, Multi-Group Analysis on two-parent famillies (한부모가족의 경제적 수준이 자녀의 학교적응에 미치는 영향: 방임적 양육태도와 정신건강의 매개효과 및 양부모가족과의 다집단 분석)

  • Kim, Hyeon Suk
    • Korean Journal of Family Social Work
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    • no.54
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    • pp.297-331
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    • 2016
  • The purpose of this study was to examine the mediating roles of neglectful rearing attitudes and mental health in the relationship between economic status of single-parent famillies and school adjustment, and the differences between single-parent and two-parent families, using structural equation modeling. Data were obtained from the Middle School 1 Panel(third-wave) of the Korean Child and Youth Panel Survey 2010. This study selected 2,195 middle school 3th-grade students (249 from single-parent families and 1,946 from two-parent families). Data were examined with structural equation modeling and multi-group analysis using AMOS 21.0, and mediating effects were tested using the Sobel test. The results were as follows; First, the single-parent children reported lower levels of economic status and school adjustment, and higher levels of neglectful rearing attitudes than the two-parent children. Second, multi-group analysis showed a statistically significant difference between single-parent and two-parent in structural equation modeling. Economic status of two-parent famillies affected school adjustment of children, but economic status of single-parent famillies did not affect school adjustment of children. Third, as a result of examining for total effect, the variable that most influenced school adjustment of children was neglectful rearing attitudes. Fourth, neglectful rearing attitudes and mental health did play a mediating role in the relationship between economic status and school adjustment in case of two-parent famillies, but neglectful rearing attitudes and mental health did not play a mediating role in case of single-parent famillies. Based on the result, this study stressed the following; First, the study suggested that problem of the single-parent famillies supporting standard which is concentrated on the low income single-parent famillies. Second, the study proposed multifaceted support measures which reflects characteristics of single-parent famillies to increase school adjustment of the single-parent children.

A Fundamental Study on the Database of Response History for Historical Earthquake Records on the Korean Peninsula (한반도 과거 지진기록에 대한 응답이력 데이터베이스 구축 기초 연구)

  • Choi, Inhyeok;Ahn, Jae-Kwang;Kwak, Dongyoup
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.39 no.6
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    • pp.821-831
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    • 2019
  • The 9.12 earthquake (2016.9.12., ML=5.8) and Pohang (2017.11.15., ML=5.4) caused social and economic damage, resulting in a greater public interest in earthquakes than in the past. In the U.S., Japan and Chile, which have high frequency of earthquakes, infrastructure facilities are already managed based on probabilistic seismic hazard analysis (PSHA) and ground motion prediction equation (GMPE) to prepare for and respond to seismic disasters. In South Korea, the aforementioned PSHA and GMPE models have been developed independently through individual researchers. However, the limited disclosure of basic data, calculation methods, and final results created during the model development poses a problem of deploying new data without updating the earthquake that occurs every year. Therefore, this paper describes how to create flatfile, which is the basic data of GMPE, and how to process for seismic waves, and how to create intensity measures.

Evaluation of the Moment Bearing Capacity of Offshore Bucket Platforms in Sand (사질토 지반에 설치된 해상 버켓작업대의 모멘트 지지력 산정)

  • Vicent, Ssenyondo;Gu, Kyo-Young;Kim, Sung-Ryul
    • Journal of the Korean Geotechnical Society
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    • v.35 no.12
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    • pp.101-109
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    • 2019
  • The bucket platform is a new structure suitable for construction of offshore bridge foundations and providing the temporary support for equipments and labour. The platform can be subjected to moment loading due to the eccentric loading or the horizontal load by wave and wind. Therefore, a three dimensional finite element analysis was performed to evaluate the moment bearing capacity of the bucket platform, varying soil density, the diameter and embedment depth of the bucket. The numerical modeling was verified and compared with the moment-rotation curve from a field loading test. The uniform sandy ground was assumed and the moment load was applied at the top plate of the platform, increasing bucket rotation. The moment-rotation relations were analyzed to determine the moment capacity, which was influenced by the embedment depth and diameter of the bucket. Finally, a preliminary design equation was suggested to estimate the moment bearing capacity.

Numerical Analysis of Two-Dimensional Nonlinear Radiation Problem Using Higher-Order Boundary Element Method (고차경계요소법을 이용한 2차원 비선형 방사문제의 수치해석)

  • Hong-G. Sung;Hang-S. Choi
    • Journal of the Society of Naval Architects of Korea
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    • v.37 no.1
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    • pp.67-81
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    • 2000
  • An accurate and efficient numerical method for two-dimensional nonlinear radiation problem has been developed. The wave motion due to a moving body is described by the assumption of ideal fluid flow, and the governing Laplace equation can be effectively solved by the higher-order boundary element method with the help of the GMRES (Generalized Minimal RESidual) algorithm. The intersection or corner problem is resolved by utilizing the so-called discontinuous elements. The implicit trapezoidal rule is used in updating solutions at new time steps by considering stability and accuracy. Traveling waves caused by the oscillating body are absorbed downstream by the damping zone technique. It is demonstrated that the present method for time marching and radiation condition works efficiently for nonlinear radiation problem. To avoid the numerical instability enhanced by the local gathering of grid points, the regriding technique is employed so that all the grids on the free surface may be distributed with an equal distance. This makes it possible to reduce time interval and improve numerical stability. Special attention is paid to the local flow around the body during time integration. The nonlinear radiation force is calculated by the "acceleration potential technique". Present results show good agreement with other numerical computations and experiments.

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A Study on the Formulae for the Compressive Stresses in Concrete Piles during Driving (콘크리트말뚝 타입시 발생하는 압축응력의 산정식에 관한 연구)

  • 임종석
    • Journal of the Korean Geotechnical Society
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    • v.15 no.1
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    • pp.5-13
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    • 1999
  • Maximum stress in pile is developed when it is driven. If the stress is greater than allowable stress of the pile, the pile will be damaged and result in stability problem. Therefore, the stress should be estimated correctly beforehand and overstress should be prevented during pile driving. There are many methods to estimate compressive stresses in concrete piles when they are driven. Nowadays, computer analysis on wave equation offers a satisfactory results. But. under certain circumstances, application of this method is difficult. Then, estimation of the stress utilizing simple formulae might be practical. In this study, relatively reasonable formulae were selected and the stresses which were measured in situ and calculated from the formulae were compared and analysed. The results show that the calculated values from Uto and Huyuki's formula were reasonably accurate and more accurate values were acquired if the values are modified by multiplying the reduction factors according to ground and construction conditions.

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Aperture Cut-off Filter for Reduction of Electromagnetic Field Penetration through a Slot in Conducting Screens (도체평판의 슬롯 침투 전자파 저감을 위한 개구면 차단필터)

  • Kim, Ki-Chai
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.12
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    • pp.1201-1211
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    • 2014
  • The purpose of this paper is to present the aperture cut-off filter for reduction of electromagnetic field penetration through a slot in conducting screen. The reduction characteristics of electric field penetration by the aperture cut-off filter are considered. In order to establish the concept of the aperture cut-off filter, the integral equation on the slot aperture field distribution is derived and solved by method of moments, and the reduction characteristics of penetration electric fields for the incident plane wave are calculated. The numerical results showed that the aperture cut-off filter for reduction of electric field penetration through the slot can be realized. To check the validity of the concept of an aperture cut-off filter and the theoretical analysis, the calculated electric field penetration of the metallic wall with narrow slot were compared with the experimental results.