• Journal of the Korean Geotechnical Society
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• v.21 no.10
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• pp.49-60
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• 2005

This paper presents the results of an investigation on the effects of design variables on the behavior of geosynthetic-reinforced modular block walls in a tiered arrangement using the finite-element method of numerical analysis. A parametric study was performed by varying the offset distance between the tiers and reinforcement length of the lower and upper tier using verified finite-element model. The finite-element analysis provided relevant information on the mechanical behavior of the tier wall and interaction mechanism between the upper and lower tier, which was otherwise difficult to obtain from the limit-equilibrium analysis based current design approaches. Practical implications of the findings obtained from this study in the current design approaches are discussed in great detail.

• Korean Journal of Social Welfare
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• v.60 no.3
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• pp.83-106
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• 2008

The Purpose of this study is to explore if people with intellectual disabilities can play a role as 'meaningful informants' in research process in Korea, by challenging the existing paradigm which consists of suspicion on the communication ability of people with intellectual disabilities and truthlessness of their statements, which results in ignorance on the covered life of people with intellectual disabilities. In this research, lessons which could learn through reinterpretation of my research experience are as follows. Firstly, the deficits of communication ability can be supplemented with restructuring interview instruments such as research questions, visual aids etc and adopting conversation analysis methods. Secondly, Suspicion on the truthlessness of their statements can be restructured by epistemological and methodological reinterpretation on the representation of social reality. Thirdly, the mechanism of exclusion and oppression according to the ignorance can be substituted by 'uncovering the life of people with intellectual disabilities', which can be basis of reconstructing the contents of programmes in the disability service centers and disability policies in the government. With these research results it could be argued that there needs to include people with intellectual disabilities as meaningful informants in the research projects funded by the government and also to provide people with intellectual disabilities with diverse roles in the research process by virtue of the development of qualitative research methods in the near future.

• Geophysics and Geophysical Exploration
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• v.12 no.1
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• pp.99-104
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• 2009

We propose a waveform inversion method for SH-wave data obtained in a shallow seismic refraction survey, to determine a 2D inhomogeneous S-wave profile of shallow soils. In this method, a 2.5D equation is used to simulate SH-wave propagation in 2D media. The equation is solved with the staggered grid finite-difference approximation to the 4th-order in space and 2nd-order in time, to compute a synthetic wave. The misfit, defined using differences between calculated and observed waveforms, is minimised with a hybrid heuristic search method. We parameterise a 2D subsurface structural model with blocks with different depth boundaries, and S-wave velocities in each block. Numerical experiments were conducted using synthetic SH-wave data with white noise for a model having a blind layer and irregular interfaces. We could reconstruct a structure including a blind layer with reasonable computation time from surface seismic refraction data.

• Journal of Digital Convergence
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• v.14 no.6
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• pp.199-218
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• 2016

The purpose of this study is to investigate the determinants of consumer's repurchase intention in the foreign direct sales shopping malls, focusing on the Japanese customers. Research model of the study is composed of seven independent variables (price competitiveness, product diversity, reputation, country-of-origin image, ease of use, delivery service, after service), a mediating variable (trust) and a dependent variable (repurchase intention). The results of this study show that trust is an important factor affecting the repurchase intention of customers. Customers' trust is affected by the reputation, country-of-origin image, ease of use, delivery service, after service. However, price competitiveness and product diversity, which are hypothesized to affect the trust, are not statistically significant. This study will provide a basis for future research on the foreign direct sales area. In addition, it will provide practical information useful in launching and/or operating the foreign direct sales malls.

• Journal of Korean Society for Geospatial Information Science
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• v.11 no.1 s.24
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• pp.3-12
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• 2003

The main objective of this study is to extract the hydro-Parameter of the Tamjin River basin. A CIS is capable of extracting various hydrological factors from DEM. One of important tasks for hydrological analysis is the division of watershed. In this study, watershed itself and other geometric factors of watershed are extracted from DEM by using a CIS technique. The data of topographical map with scale of 1:25,000 and 1:250,000 in the Tamjin River basin is used for this study and it is converted to DEM date. Various forms of representation of spatial data are handled in main modules and a CRID module of ArcView. A GRID module is used on a stream in order to define watershed boundary. Based on the spatial analysis using those GIS technique, it would be possible to obtain the reasonable results of watershed characteristics. Also, the results show not only that GIS can aid watershed management, research and surveillance, but also that the geometric characteristics as parameters of watershed can be quantified more accurately and easily than conventional graphic methods. From the equations($Y=14632.87{\cdot}X^{-0.542444},\;Y=37014.1{\cdot}X^{-1.058808}$), it can be concluded that the optimal count of flow accumulation is 468 and cell size is 42m for spatial analysis by using GIS technique in Tamjin River basin.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.26.3-27
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• 2009

한 기의 영상레이더 위성을 이용하여 동일한 촬영지역에 대해 적절한 기선벡터(Baseline)을 유지하는 두 장(scene)의 영상을 획득하여 그 지역의 정밀 표고차를 추출하는 레이더 간섭계(Interferometry) 임무를 수행하기 위해서는 반복지상궤적을 유지하도록 위성의 궤도를 주기적으로 조정해 주어야 한다. 이 연구에서는 반복지상궤적 유지 정밀도를 극대화시키기 위하여 최적의 기준궤도를 생성하고 이를 유지하기 위한 속도증분 및 궤도 조정 일정을 산출할 수 있는 궤도최적화 S/W 를 개발하였다. 이 연구의 최적 궤도 설계 문제는 다음과 같다. "시작시간 $T_0$에서 초기 접촉궤도 상태벡터 (ECEF 위치 및 속도벡터) $x_0$이고, 지상궤적반복주기 p 이후의 시간 $T_0+p$에서도 초기 접촉궤도 상태벡터와 동일한$x_0$가 되도록 궤도를 유지하려고 할 때, 여명 궤도(dawn-dusk and sun-synchronous orbit)에서 운영되는 위성의 연료소모(또는 속도증분)를 최소화시키는 가상의 궤도조정(maneuver) 횟수, 시기, 크기를 찾아라." 이 연구에서는 궤도최적화 문제를 풀기 위하여 GRACE 중력모델(GGM02C)이 적용된 수치적 방법의 위성궤도예측 알고리즘을 시스템 설계에 적용하였고, 매개변수 최적화 방법 중 구속조건이 있는 비선형 최적화 기법의 하나인 연속 2차 계획법(sequential quadratic programming)을 사용하여 해를 구하였다. 개발된 궤도최적화 S/W의 성능을 분석하기 위하여 고도 550km의 여명궤도를 돌며 지상궤적반복주기가 28일인 영상레이더 위성에 대해 적용하였다. 해석 결과를 통해, 비록 시스템의 비선형이 큼에도 불구하고 최소의 속도증분으로 정밀한 반복지상궤적이 유지됨을 알 수 있었다.

• Korean Journal of Food Science and Technology
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• v.22 no.5
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• pp.497-502
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• 1990

The effect of sugar concentration, immersion time and temperature on water loss, solid gain or loss, and sugar molality of potatoes during osmotic concentration was analyzed by a response surface methodology (RSM), and those values were predicted by using a second degree polynomial regression model. Effect of osmotic concentration and blanching on vitamin C retention of air dried potatoes (6% MC: wet basis) was also evaluated. The most significant factor was sugar concentration for water loss, solid gain or loss, sugar molality, rate parameter and retention of vitamin C. Second and third factors were immersion time and temperature respectively. Water loss and solid gain were rapid in the first 10 min and then levelled off. A 44.6% of water loss was observed during osmotic concentration using a sugar solution $(60\;Brix,\;80^{\circ}C$) with 20 min of immersion time. Dried potatoes after osmotic concentration had higher vitamin C content than dried potatoes after blanching. Optimum regions for osmotic concentration process of potatoes were $60-70^{\circ}C$ of immersion temperature, 60 Brix of sugar solution and 16-20 min of immersion time based on above 30% of water loss and 50% of vitamin C retention.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.1053-1056
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• 2008

Permeability coefficient of concrete is a substantial key parameter for understanding the durability performance of concrete and its micro-structural densification. Many researches to deal with the issue have been accomplished, however, it is very rare to deal with the theoretical study on permeability coefficient in connection with carbonation of concrete and the effect of volumetric fraction of cement paste or aggregate on the permeability coefficient. The majority of these researches have not dealt with this issue combined with carbonation of concrete, although carbonation can significantly impact on the permeability coefficient of concrete. The purpose of this study is to establish a fundamental approach to compute the permeability coefficient of (non)carbonated concrete. When simulating micro-structural characteristics as a starting point for deriving a model for the permeability coefficient by the numerical simulation program for cementitious materials, HYMOSTRUC, a more realistic formulation can be achieved. For several compositions of cement pastes, the permeability coefficient is calculated with the analytical formulation, followed by a microstructure-based model. Emphasis is on the micro-structural changes and its effective change of the permeability coefficient of carbonated concrete. The results of micro-structural water permeability coefficient model will be compared with results achieved from permeability experiments.

• Journal of Intelligence and Information Systems
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• v.20 no.2
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• pp.19-38
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• 2014

This study focused on the role of active knowledge seeking (knowledge browsing and knowledge searching) in the context of virtual community of interest. Knowledge seeking is rarely studied as an antecedent in knowledge management (KM) research. Active knowledge seeking is considered as antecedents of sense of virtual community which mediates to knowledge sharing intention and virtual community promotion. Research hypotheses are tested by applying structure equation modeling with survey data from virtual community members in South Korea. Active knowledge seeking behavior was found to be the strong predictor of sense of virtual community, which, in turn, positively affects knowledge sharing intention and virtual community promotion. Implication to practitioners is to understand and accommodate the members' knowledge seeking efforts, who are potential contributors and promoters of the virtual community. Knowledge seeking, knowledge sharing and promoting virtual community are more of human activities than technology and this study extends the understanding of such human activities. By providing a mechanism of how knowledge seeking and sharing could work harmoniously, a virtuous circle with win-win situation could be achieved in virtual communities.

• Journal of Digital Convergence
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• v.12 no.10
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• pp.515-523
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• 2014

The purpose of this study was to identify the structural relationship model between teacher attachment, peer attachment, self-encouragement, career self-efficacy, and career maturity and to analyze the direct or indirect effect among latent variables. 220 elementary school students in a Cheongju were sampled. Four measurement instruments were employed; the Teacher Attachment Peer Attachment Scale, Self-encouragement Scale, the Career self-efficacy and the Career Maturity scale. The Collected data were analyzed by correlation and regression alalysis with SPSS program and Structural Equation major Modeling(SEM) and fitness of the final model were CFI=.957, TLI=.951, RMSEA=.049. The results of this study were as follows: First, there were significant positive correlations among teacher attachment, peer attachment, self-encouragement, career self-efficacy, and career maturity. Second, according to the structural equation modeling, the results showed that self-encouragement and career self-efficacy mediated the effect of teacher attachment, peer attachment on career maturity.