• Journal of Korean Association for Spatial Structures
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• v.23 no.2
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• pp.53-60
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• 2023

Recently, a novel cast-in specialty insert was developed in Korea as an anchor for lightweight pipe supports, including fire-protection pipes. As these pipe supports and anchors play a critical role in transferring loads of fire-protection pipes to structural members, it is crucial to evaluate their seismic performance before applying the newly developed insert. In this study, the seismic shear performance of the insert anchors was evaluated through cyclic loading tests based on the loading protocols of ACI 355.2 and FEMA 461. Initially, five monotonic loading tests were conducted on the insert anchors in cracked concrete, followed by cyclic loading tests based on the monotonic test results. The findings revealed that the insert anchors exhibited negligible decrease in shear strength even after cyclic loading. Furthermore, a comparison of the maximum load and displacement of the insert anchors obtained under the loading protocols of ACI 355.2 and FEMA 461 was performed to investigate the applicability of the FEMA 461 loading protocol for anchor performance evaluation.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4030-4048
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• 2022

In this study, road transportation tests were conducted with surrogate fuel assemblies under normal conditions of transport to evaluate the vibration and shock load characteristics of spent nuclear fuel (SNF). The overall test data analysis was conducted based on the measured acceleration and strain data obtained from the speed bump, lane-change, deceleration, obstacle avoidance, and circular tests. Furthermore, representative shock response spectrums and power spectral densities of each test mode were acquired. Amplification or attenuation characteristics were investigated according to the load transfer path. The load attenuated significantly as it transferred from the trailer to the cask. By contrast, the load amplified as it transferred from the cask to the surrogate SNF assembly. The fuel loading location on the cask disk assembly did not exhibit a significant influence on the strain measured from the fuel rods. The principal strain was in the vertical direction, and relatively large strain values were obtained in spans with large spacing between spacer grids. The influence of the lateral location of fuel rods was also investigated. The fuel rods located at the side exhibited relatively large strain values than those located at the center. Based on the strain data obtained from the test results, a hypothetical road transportation scenario was established. A fatigue evaluation of the SNF rod was performed based on this scenario. The evaluation results indicate that no fatigue damage occurred on the fuel rods.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.100-101
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• 2021

Facilities with high risk of a disaster or requiring continuous safety management are designated as class-III facility. In order to designate a class-III facility, it is evaluated based on the safety status of the facility, the risk to the building users, and the number of years elapsed of the facility, etc. and this shall be referred to the actual condition survey for the designation of a class-III facility. In the actual condition survey conducted to designate the safety status is calculated by the checklist based on the evaluation scores consisting of five stages each item, and is evaluated in three stages by 'good', 'careful observation', and 'designated review' through the average of the combined scores. Currently, the actual condition survey being conducted applies only structural stability, and the risk factors such as damage to the finish, the risk of cracking, and the type and weight of major structures are not included in the checklist for the actual condition survey, so even if experts think it is dangerous, scores cannot be reflected. Therefore, this study aims to analyze the problems of checklist of the actual condition survey for the designation of class-III facility and to propose an improvement plan for the checklist for the actual condition survey.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.671-672
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• 2021

본 논문에서는 작전환경과 위장무늬 디자인 영상 간의 색상 및 구조 분석 기반의 새로운 정량적 위장무늬 평가 방법을 제안한다. 작전환경 및 위장무늬 디자인 영상 간 RGB, Lab 색상 공간에서의 화소간 평균 오차 및 색상 히스토그램 비교를 통해 색상 유사도를 계산한다. 또한, PSNR(Peak Signal-to-Noise Ratio), MSSIM(Mean Structural Similarity Index), UIQI, GMSD 및 딥러닝 기반 영상 간 구조 유사도를 계산한다. Random Forest Regressor를 통해 각각 계산된 색상 및 구조 유사도 파라미터를 회기 분석하여 최종 위장무늬 평가 결과를 계산한다. 20명의 피실험자를 대상으로 제안한 위장무늬 평가 방법과 기존 평가 방법을 비교함을 통해 제안한 방법의 성능을 검증하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.499-501
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• 2021

Recently, artificial intelligence and SW have occupied an important position worldwide as the foundation technology of the era of the 4th industrial revolution, and web browser-based programming learning systems are becoming common due to changes in the learning environment caused by COVID-19. In accordance with this trend, this paper proposes a functionally scalable microservice-based system structure for an online evaluation system as a tool for learning algorithms that are the basis of artificial intelligence and SW. In addition, a functional structure for applying machine learning to automatic evaluation functions under the proposed system structure is also proposed.

• Journal of Korean Association for Spatial Structures
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• v.22 no.4
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• pp.31-38
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• 2022

In this study, an incremental loading test of the HRS(Hybrid Rubber Slit) damper was additionally performed to define the physical characteristics according to the incremental test results, and an analytical study was performed according to the damping design procedure by selecting an example structure. As a result of performing seismic performance evaluation before reinforcement by selecting a RC structure similar to an actual school structure as an example structure, the story drift ratio was satisfied, but some column members collapsed due to bending deformation. In order to secure the seismic performance, the damping design procedure of the HRS damper was presented and performed. As a result of calculating the amount of damping device according to the expected damping ratio and applying it to the example structure, the hysteresis behavior was stable without decrease in strength, and the story drift ratio and the shear force were reduced according to the damping effect. Finally the column members that had collapsed before reinforcement satisfied the LS Level.

• Computers and Concrete
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• v.32 no.5
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• pp.475-486
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• 2023

Nondestructive evaluation (NDE) is an important task of civil engineering structure monitoring and inspection, but minor damage such as small cracks in local structure is difficult to observe. If cracks continued expansion may cause partial or even overall damage to the structure. Therefore, monitoring and detecting the structure in the early stage of crack propagation is important. The crack detection technology based on machine vision has been widely studied, but there are still some problems such as bad recognition effect for small cracks. In this paper, we proposed a deep learning method based on sweep signals to evaluate concrete surface crack with a width less than 1 mm. Two convolutional neural networks (CNNs) are used to analyze the one-dimensional (1D) frequency sweep signal and the two-dimensional (2D) time-frequency image, respectively, and the probability value of average damage (ADPV) is proposed to evaluate the minor damage of structural. Finally, we use the standard deviation of energy ratio change (ERVSD) and infrared thermography (IRT) to compare with ADPV to verify the effectiveness of the method proposed in this paper. The experiment results show that the method proposed in this paper can effectively predict whether the concrete surface is damaged and the severity of damage.

• Educational Technology International
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• v.24 no.2
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• pp.203-236
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• 2023

The purpose of this study is to explore the structural relationship between COVID-19-induced sub-dimensions of Online Self-Regulated Learning (OSRL) and satisfaction in online courses conducted in the 'post-COVID-19 era,' as well as to investigate the moderating effects of situational variables such as 'course planning,' 'device type,' and 'course repetition.' To achieve this, the study constructs a measurement model with sub-dimensions of Environment Structuring, Learning Strategy, Help Seeking, and Self-Evaluation as components of OSRL. Participants in this study were selected from university students who enrolled in online courses offered by the Department of Education at University A in the metropolitan area. The research findings reveal several key insights. First, among the sub-dimensions of Online Self-Regulated Learning, Environment Structuring, Learning Strategy, and Self-Evaluation significantly influence satisfaction with online courses. Second, students' satisfaction with online courses significantly influences their intention to continue participating in such courses. Third, 'course planning' during online course hours and 'course repetition' play a moderating role in the relationship between sub-dimensions of Online Self-Regulated Learning and satisfaction. Based on the discussion of these research results, this study concludes by suggesting some future implications and challenges of online courses.

• The Journal of Economics, Marketing and Management
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• v.11 no.5
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• pp.57-67
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• 2023

Purpose: An evaluation of Uzbekistan's steps towards competitiveness for FDI globally is presented in this paper. Specifically, the purpose of this paper is to analyze the case of Uzbekistan, and to determine the strategies that can be implemented to increase the competitiveness in attracting foreign investment. Research design, data and methodology: To investigate the FDI environment and identify effective strategies, Global RPM and QSPM analyses were conducted in addition to in-depth interviews with experts. In particular, this study uses the method of Global RPM analysis to make a comprehensive evaluation and analysis on globalization, rationality, and professionalism and morality dimensions of FDI in Uzbekistan. Results: According to the analysis, the conditions of political situation, financial stability, legal frameworks, as well as economic environment of the country play a significant role in bringing in FDIs from abroad. Moreover, based on the results, Uzbekistan scored lowest on globalization, indicating that the country has a low level of integration and openness to the global economy and society. Conclusions: Uzbekistan can boost its productive capacity and GDP growth with FDI, but it has to overcome many structural and logistical obstacles. Furthermore, adhering to the chosen strategies, policymakers can leverage FDI to stimulate economic growth, leading to the generation of new jobs and expanded opportunities in Uzbekistan.

• Journal of Distribution Science
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• v.22 no.5
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• pp.117-129
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• 2024

Purpose: This research aims to explore the ramifications of job stress on cabin crews within the air service distribution sector, specifically examining its impact on service quality through mediating variables such as job satisfaction and engagement during the pandemic era. Research design, data and methodology: The study is based on a sample size of 312 individuals, exclusively comprising cabin crews employed in the airline industry. Methodologically, Confirmatory Factor Analysis (CFA) and Structural Equation Modeling (SEM) were employed for statistical analysis. Results: The findings reveal that both performance evaluation and job responsibility exerted a significant impact on both job satisfaction and job engagement. Furthermore, job engagement demonstrated a substantial influence on service quality. However, in contrast, factors like unstable employment and the working environment showed no significant impact on either job satisfaction or engagement. Additionally, job satisfaction did not exert a significant influence on service quality. Conclusions: These insights will offer the valuable guidance to the airline industry in preparing for unforeseen external environments that may affect the industry. As the aviation sector navigates the challenges posed by the pandemic, understanding and addressing the intricate relationships among job stress, satisfaction, engagement, and service quality will be crucial for effective industry resilience and adaptation.