• Korean Journal of Legislative Studies
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• v.23 no.1
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• pp.81-111
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• 2017

This article analyzes three major issues related to regional voting in South Korea. First, is regional voting a regional problem or an ideological problem? Second, is regional voting caused by regional identity or regional interest? Third, has regionalism waxed or waned? Analyses of the cumulative data set since the 15th presidential election yield the following results. First, Yongnam people are more conservative than Honam people. Second, regional voting consists of ideological and regional components. Third, there exist both a hometown effect and an abode effect in regional voting, but the latter is significantly greater than the former. Forth, regionalism had weakened between the 15th National Assembly election and the 16th Presidential election, but has not varied much since then.

• Journal of Information Technology Services
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• v.20 no.5
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• pp.43-54
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• 2021

Currently, citizens' expectations and concerns on utilizing artificial intelligence (AI) technologies in the public sector are widening with the rapid digital transformation. Furthermore the level of global acceptance on the AI and other intelligent digital technologies is augmenting with the needs of non-face-to-face types of public services more than ever due to the unforeseen and unpredictable pandemic, COVID-19. Thus, this study intended to empirically examine what policy directions for the public should be considered to provide well-designed services as well as to promote the evidence-based public policies in terms of Al speaker technology as a non-contact smart city service. Based on the survey of senior citizens' perceptions on AI (AI Speaker technology), this study conducted structure equation modeling analyses to identify whether technology acceptance models on to the varied dependent variables such as actual use, perception, attitude, and brand royalty. The Results of the empirical analyses showed that AI increased the positive level of citizens' perception, attitude and brand royalty on non-contact public services (smart city services) which are becoming more crucial for developing AI oriented government and providing intelligent public services effectively. In addition, theoretical and practical implications are discussed for understanding the changes of public service in the post-corona.

• Journal of Ocean Engineering and Technology
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• v.36 no.1
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• pp.11-20
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• 2022

Generally, tsunamis are generated by the rapid crustal movements of the ocean floor. Other factors of tsunami generation include landslides on coastal and ocean floor slopes, glacier collapses, and meteorite collisions. In this study, two numerical analyses were conducted to examine the formation, propagation, and deformation properties of landslide tsunamis. First, LS-DYNA was adopted to simulate the formation and propagation processes of tsunamis generated by dropping rigid bodies. The generated tsunamis had smaller wave heights and wider waveforms during their propagation, and their waveforms and flow velocities resembled those of theoretical solitary waves after a certain distance. Second, after the formation of the landslide tsunami, a tsunami based on the solitary wave approximation theory was generated in a numerical wave tank (NWT) with a computational domain that considered the stability/steady phase. The comparison of two numerical analysis results over a certain distance indicated that the waveform and flow velocity were approximately equal, and the maximum wave pressures acting on the upright wall also exhibited similar distributions. Therefore, an effective numerical model such as LS-DYNA was necessary to analyze the formation and initial deformations of the landslide tsunami, while an NWT with the wave generation method based on the solitary wave approximation theory was sufficient above a certain distance.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.1
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• pp.95-103
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• 2010

In this paper, a new soft ground tunneling technique termed the PNT method(Pre-Nailed Tunneling Method) is studied. Mechanism of the method is investigated in terms of theoretical and numerical approaches. The pre-nailing effects are validated by performing two dimensional numerical analyses. It is identified that the method is successful in soft grounds, and greatly efficient in reducing the ground deformation by nailing the ground. To develop the design guidelines of the method, numerical parametric analyses on the installation range and angle were also carried out.

• Steel and Composite Structures
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• v.44 no.5
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• pp.651-676
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• 2022

Most of the experimental, theoretical, and numerical studies on the stability of functionally graded composites are deterministic, while there are full of complex interactions of variables with an inherently probabilistic nature, this paper presents a non-intrusive framework to investigate the stochastic nonlinear buckling behaviors of porous functionally graded cylindrical shells exposed to inevitable source-uncertainties. Euler-Lagrange equations are theoretically derived based on the three variable refined shear deformation theory. Closed-form solutions for the shell buckling loads are achieved by solving the deterministic eigenvalue problems. The analytical results are verified with numerical results obtained from finite element analyses that are conducted in the commercial software ABAQUS. The non-intrusive framework is completed by integrating the Monte Carlo simulation with the verified closed-form solutions. The convergence studies are performed to determine the effective pseudorandom draws of the simulation. The accuracy and efficiency of the framework are verified with statistical results that are obtained from the first and second-order perturbation techniques. Eleven cases of individual and compound uncertainties are investigated. Sensitivity analyses are conducted to figure out the five cases that have profound perturbative effects on the shell buckling loads. Complete probability distributions of the first three critical buckling loads are completely presented for each profound uncertainty case. The effects of the shell thickness, volume fraction index, and stochasticity degree on the shell buckling load under compound uncertainties are studied. There is a high probability that the shell has non-unique buckling modes in stochastic environments, which should be known for reliable analysis and design of engineering structures.

• Physical Therapy Rehabilitation Science
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• v.12 no.3
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• pp.346-354
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• 2023

Objective: The objective of this study is to provide medical institutions with theoretical basis by analyzing the effect of service quality-related factors. It will be helpful for hospitals to enhance service quality which will be of use to attain customer satisfaction and ultimately competitive advantage. Design: An empirical study. Methods: To verify the model, I conducted a questionnaire survey analysis. Items for measurement have been extracted from several related studies on medical industry. The survey target has been set by convenience sampling method and consists of citizens reside in Seoul and Gyeonggi-do Province, and total number of 161 samples have been analyzed. To verify validity and reliability, I conducted factor analysis and reliability analysis, and for hypotheses verification, multiple regression analyses have been performed. Results: This study aims to investigate the relation between service quality factors and customer satisfaction, and also those factors and customer loyalty. Service quality factors consist of Tangibles(X1), Reliability(X2), Assurance(X3), Responsiveness(X4), and Empathy(X5). According to the results of regression analyses, X1, X2, X3, and X5 have been proved to have positive relations with customer satisfaction and loyalty, whereas hypothesis related X4 has not been supported. Finally, customer satisfaction has been founded to affects positively to customer loyalty. Conclusions: Service quality factors are significantly related to customer satisfaction and loyalty. So medical institutions should aware of this and try to enhance service quality for attaining competitive advantage.

• Korean Journal of Agricultural Science
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• v.50 no.3
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• pp.489-498
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• 2023

Cabbage, which is one of the main materials of kimchi, normally has an unstable supply due to cultivation and climate conditions. This unstable supply negatively affects the profitability of kimchi processors in Korea. Thus, kimchi processors found a better method for acquiring a consistent cabbage supply with long-term storage of over 3 months. However, a consensus regarding the best method for the stable and economical acquisition of cabbage remains controversial. This study aimed to analyze the current issue concerning cabbage acquisition by kimchi processors and evaluate the economic feasibility of kimchi storage. Findings obtained through survey and economic analyses using theoretical methodology were as follows: First, A survey conducted on kimchi processors in Korea revealed that even though they recognize the importance of kimchi storage, they struggle to store adequate amounts of cabbage. This is particularly evident with summer cabbage, which experiences the highest supply volatility and thus requires greater attention from kimchi processors in terms of storage. Second, the price analyses using the coefficient of variation show that cabbage in Korea has a high level of price instability, which suggests more storage of cabbage. Third, the evaluation of the economic feasibility of cabbage storage indicated that kimchi processors should consider storing a greater amount of cabbage, particularly during the summer season. This approach can help reduce the overall cost associated with kimchi processing.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1477-1482
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• 2015

In order to find out the effect of embedment ratio on behavior compensated foundation, numerical analyses were performed. Bearing capacity ratios obtained from numerical analyses were greater than those obtained from theoretical equations and it could be seen that the bearing capacity ratio was proportional to the embedment ratio with only exception of the case of square footing in which bearing capacity ratio was increased rapidly with the embedment ratio. For the case of strip footing on sand, the bearing capacity ratios obtained from the numerical analyses and Meyerhof equation were similar with each other and magnitudes of those were as much as square of the embedment ratio but the bearing capacity ratios were little affected by the embedment ratios for the case of strip footing on clay. It can be said that the bearing capacity ratios obtained from the square footing are greater than those obtained from the strip footing. According to the numerical analysis, values of settlement ratios which correspond to the embedment ratio of one were about 0.4 and settlement ratios were decreased with increase of the embedment ratios. Settlement ratios of the loose sand were smaller than those of the dense sand and the clay.

• Steel and Composite Structures
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• v.29 no.3
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• pp.405-422
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• 2018

In this research, experimental tensile test and manufacturing of carbon nanotube reinforced composite beam (CNTRC) is presented. Also, bending, buckling, and vibration analysis of CNTRC based on various beam theories such as Euler-Bernoulli, Timoshenko and Reddy beams are considered. At first, the experimental tensile tests are carried out for CNTRC and composite beams in order to obtain mechanical properties and then using Hamilton's principle the governing equations of motion are derived for Euler Bernoulli, Timoshenko and Reddy theories. The results have a good agreement with the obtained results by similar researches and it is shown that adding just two percent of carbon nanotubes increases dimensionless fundamental frequency and critical buckling load as well as decreases transverse deflection of composite beams. Also, the influences of different manufacturing processes such as hand layup and industrial methods using vacuum pump on composite properties are investigated. In these composite beams, glass fibers used in an epoxy matrix and for producing CNTRC, CNTs are applied as reinforcement particles. Applying two percent of CNTs leads to increase the mechanical properties and increases natural frequencies and critical buckling load and decreases deflection. The obtained natural frequencies and critical buckling load by theoretical method are higher than other methods, because there are some inevitable errors in industrial and hand layup method. Also, the minimum deflection occurs for theoretical methods, in bending analysis. In this study, Young's and shear modulli as well as density are obtained by experimental test and have not been used from the results of other researches. Then the theoretical analysis such as bending, buckling and vibration are considered by using the obtained mechanical properties of this research.

• Structural Engineering and Mechanics
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• v.72 no.2
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• pp.169-180
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• 2019

The underlying mechanism of the wind-induced vibration of the hangers of the suspension bridges is still not fully understood at present and hence is comprehensively examined in this study. More specifically, a series of field measurements on the No. 2 hanger of the Xihoumen Bridge was first carefully conducted. Large amplitude vibrations of the hanger were found and the oscillation amplitude of the leeward cable was obviously larger than that of the windward cables. Furthermore, the trajectory of the leeward cable was close to an ellipse, which agreed well with the major characteristics of wake-induced vibration. Then, a theoretical model for the wake-induced vibration based on a 3-D continuous cable was established. To obtain the responses of the leeward cable, the finite difference method (FDM) was adopted to numerically solve the established motion equation. Finally, numerical simulations by using the structural parameters of the No. 2 hanger of the Xihoumen Bridge were carried out within the spatial range of $4{\leq}X{\leq}10$ and $0{\leq}Y{\leq}4$ with a uniform interval of ${\Delta}X={\Delta}Y=0.25$. The results obtained from numerical simulations agreed well with the main features obtained from the field observations on the Xihoumen Bridge. This observation indicates that the wake-induced vibration might be one of the reasons for the hanger oscillation of the suspension bridge. In addition, the effects of damping ratio and windward cable movement on the wake-induced vibration of the leeward cable were numerically investigated.