• International Area Studies Review
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• v.12 no.3
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• pp.69-88
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• 2008

Firms or internal exchanges exist to eliminate or at least reduce transaction costs from the separating process in many firms by dealing more efficiently with bounded rationality, complexity, and tendency towards opportunism faced by the markets so that vertical integration is supposed to have a positive relationship with performance. The organizational structure of Korean economy in the latter part of the $20^{th}$ century is much related with this transaction costs' view. I propose to estimate the effect of vertical integration on the firm's performance using the data of the Korean listed corporations from 1991 to 1995, therefore. The estimated results show that vertical integration at firm level is negatively and significantly related with the firm's performance: the higher level of vertical integration the worse performance. However, the group level integration is not related with performance at all.

• Journal of Life Science
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• v.29 no.10
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• pp.1159-1163
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• 2019

Although there is a growing interest in male menopause, a phenomenon associated with male hormone depletion, current kits using antibodies to quantify male hormones are expensive. In this study, we constructed an in vitro system for verifying the activity or concentration of male steroid hormones using a transcriptional activity test. A reporter plasmid, pGL2-Neo-ARE-AdE1BTATA, which reacts to testosterone, was constructed. In this plasmid, the ARE-AdE1bTATA sequences can be bounded by the testosterone - androgen receptor complex to express luciferase as a reporter. Then, a stable transfection was performed on the human prostate cancer cell line, LNcap-LN3. The constructed LNcap-LN3/pGL2-Neo-ARE-AdE1BTATA testosterone compound detection (TCD) system showed quantitatively proportional luciferase activities to concentrations of $10^{-13}$ to $10^{-8}M$ of standard testosterone. The established in vitro TCD system will contribute to the development of materials for health/functional foods and drugs as it will be possible to search en masse for testosterone-like or testosterone-inhibiting substances derived from natural materials.

• The Korean Journal of Applied Statistics
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• v.32 no.1
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• pp.99-109
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• 2019

We compared the confidence intervals of estimators using various bootstrap methods for a Random Coefficient Autoregressive(RCA) model. We consider a Quasi score estimator and M-Quasi score estimator using Huber, Tukey, Andrew and Hempel functions as bounded functions, that do not have required assumption of distribution. A standard bootstrap method, percentile bootstrap method, studentized bootstrap method and hybrid bootstrap method were proposed for the estimations, respectively. In a simulation study, we compared the asymptotic confidence intervals of the Quasi score and M-Quasi score estimator with the bootstrap confidence intervals using the four bootstrap methods when the underlying distribution of the error term of the RCA model follows the normal distribution, the contaminated normal distribution and the double exponential distribution, respectively.

• Computers and Concrete
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• v.23 no.6
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• pp.433-444
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• 2019

As rice husk ash (RHA) is not produced in controlled manufacturing process like cement, its properties vary significantly even within the same lot. In fact, properties of Rice Husk Ash Based Concrete (RHABC) are largely dictated by uncertainty leading to huge deviations from their expected values. This paper proposes a Robust Cost Optimization (RCO) procedure for RHABC, which minimizes such unwanted deviation due to uncertainty and provides guarantee of achieving desired strength and workability with least possible cost. The RCO simultaneously minimizes cost of RHABC production and its deviation considering feasibility of attaining desired strength and workability in presence of uncertainty. RHA related properties have been modeled as uncertain-but-bounded type as associated probability density function is not available. Metamodeling technique is adopted in this work for generating explicit expressions of constraint functions required for formulation of RCO. In doing so, the Moving Least Squares Method is explored in place of conventional Least Square Method (LSM) to ensure accuracy of the RCO. The efficiency by the proposed MLSM based RCO is validated by experimental studies. The error by the LSM and accuracy by the MLSM predictions are clearly envisaged from the test results. The experimental results show good agreement with the proposed MLSM based RCO predicted mix properties. The present RCO procedure yields RHABC mixes which is almost insensitive to uncertainty (i.e., robust solution) with nominal deviation from experimental mean values. At the same time, desired reliability of satisfying the constraints is achieved with marginal increment in cost.

• Structural Engineering and Mechanics
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• v.78 no.1
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• pp.53-66
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• 2021

The determination of the damage index to reveal the performance level of a structure can constitute the seismic risk generalization approach based on the parametric analysis. This study implemented this concept to one kind of civil engineering structure that is the concrete gravity dam. Different cases of the structure exhibit their individual responses, which constitute different considerations. Therefore, this approach allows the parametric study of concrete as well as soil for evaluating the seismic nature in the generalized case. To ensure that the target algorithm applicable to most of the concrete gravity dams, a very simple procedure has been considered. In order to develop a correlated algorithm (by response surface methodology; RSM) between the ground motion and the structural property, randomized sampling was adopted through a stochastic method called half-fractional central composite design. The responses in the case of fluid-foundation-dam interaction (FFDI) make it more reliable by introducing the foundation as being bounded by infinite elements. To evaluate the seismic generalization of FFDI models, incremental dynamic analysis (IDA) was carried out under the impacts of various earthquake records, which have been selected from the Pacific Earthquake Engineering Research Center data. Here, the displacement-based damage indexed fragility curves have been generated to show the variation in the seismic pattern of the dam. The responses to the sensitivity analysis of the various parameters presented here are the most effective controlling factors for the concrete gravity dam. Finally, to establish the accuracy of the proposed approach, reliable verification was adopted in this study.

• International Area Studies Review
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• v.14 no.2
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• pp.3-23
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• 2010

The purpose of the study is to estimate value of the Eulsukdo that is attracting lots of birds. Eulsukdo became one of the most famous eco-tourism destinations worldwide and environmental restoration work is progressing with enormous budget. The input of the budget by policy judgement basically can be justified when the benefit excesses the cost in social aspect. Eulsukdo has external effect as cultural tourism resource but it is difficult to estimate the value in market. The study is to estimate the value of Eulsukdo through the single-bounded dichotomous CVM(Contingent Valuation Methods). According to analysis results, the mean WTP(Willingness to Pay) and the truncated mean WTP are estimated at 5,240 and 3,374 won in the log-normal model, and 5,888 and 3,232 won in the log-logistic model respectively. The annual total benefits value based on the truncated mean WTP is estimated at 3,870 million won in the log-normal model and 4,040 million won in log-logistic model. The result of this study will provide useful guide to policy makers and developers who fully realize the value of public goods.

• (The)Study of the Eastern Classic
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• no.32
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• pp.51-69
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• 2008

Lu Xun was closely bounded with art since he was young, and he had a thorough knowledge of art. This treatise discerned how Lu Xun substituted and expressed his emotion through his work of art, and what was characteristic of his selection and combination of colors. Truly, color is related to statement of human mind. Lu Xun expressed certain color either consciously or unconsciously when he created human figure. The group of black in human figure in his art is representative example of it. Lu Xun always used heavy and dark color to emphasize human figure so that people can assume their lives and character. This artistic mentality or, great choice of art, relates to Lu Xun's individual life and state of mind. However, Lu Xun did not always choose dark color. Sometimes he looked squarely at darkness and tried to pursue bright color presupposing 'hope' at the same time.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.3
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• pp.134-140
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• 2022

Ship local structure sometimes experiences severe vibration due to the resonance with an excitation force generated by the propulsion system. In that case, the installation of dynamic vibration absorber such as Tuned Mass Damper (TMD) on the structure can be considered as an effective alternative countermeasure to reduce the troublesome vibration if structural modification or change of excitation frequencies is difficult. Meanwhile, the conventional optimal design method of TMD premises the target structure exposed on an excitation force without the constraint of its magnitude and frequency range. However, the frequencies of major ship excitation forces due to propulsion system are normally bounded and its magnitude is varied according to its operation speed. Hence, the optimal design of TMD to reduce the resonant vibration of ship local structure should be differently approached compared with the conventional ones. For the purpose, this paper proposes an optimal design method of TMD considering maximum frequency and magnitude variation of a target harmonic excitation component. It is done by both lowering the resonant response at the 1st natural frequency and locating the 2nd natural frequency over maximum excitation frequency for the idealized 2 degree of freedom system consisted of the structure and the TMD. For the validation of the proposed method, a numerical design case of TMD for a ship local structure exposed on resonant vibration due to a propeller excitation force is introduced and its performance is compared with the conventionally designed one.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.2
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• pp.181-186
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• 2022

Poisson-Boltzmann equation (PBE) is used to model problems arising from various disciplinary including bio-pysics and colloid chemistry. Therefore, to predict a numerical solution of PBE is an important issue. The authors proposed deep learning based methods to solve PBE while the computational time to generate finite element method (FEM) solutions were bottlenecks of the algorithms. In this work, we shorten the generation time of FEM solutions in two directions. First, we experimentally find certain penalty parameter in a bilinear form. Second, we applied algebraic multigrids methods to the algebraic system so that condition number is bounded regardless of the meshsize. In conclusion, we have reduced computation times to solve algebraic systems for PBE. We expect that algebraic multigrids methods can be further employed in various disciplinary to generate deep learning samples.

• Korean Journal of Culture and Social Issue
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• v.22 no.4
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• pp.643-674
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• 2016

The purpose of present study is to discover the meaning of the Eogul(억울) which is known as a emotion from perceived unfairness. Even though Eogul has been mentioned as a cause of the Hwabyung in Korean culture there were few studies about it. Researchers designed two studies to provide clear understanding for this concept. In study 1, researchers conducted an open-ended questionnaire for 44 participants to deduce the cultural contexts and the whole experience on Eogul. Data were analyzed with grounded theory, the results were cross-checked by different evaluators. According to the analysis, Eogul is not only the negative feelings from the perceived unfairness, but also the motivations and behaviors to resolve the feelings. Especially, what makes Eogul culture-bounded could be related display rules on expressing emotions. We conducted study 2 to clarify the cultural attributes of Eogul in Korean culture. Variables that explain cultural differences were chosen and 123 participants were surveyed with them including the items developed for measuring Eogul. Cultural meanings and implications of Eogul were discussed with the results.