• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.3
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• pp.286-291
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• 2023

Perovskite materials are promising candidates for next-generation optoelectronic devices owing to their outstanding external quantum efficiency, high color purity, and ability to tune the light emission wavelength. However, conventional thermal annealing processes caused the degradation of perovskite, resulting in poor optoelectronic properties and a short lifetime. Herein, we propose a laser-induced recrystallization of perovskite thin film to enhance its light-emitting properties. Laser-induced recrystallization process was performed using rapid and instantaneous laser heating, which successfully induced grain growth of the perovskite material. The laser processing conditions were thoroughly optimized based on theoretical calculations and various material analyses such as x-ray diffraction, scanning electron microscope, and photoluminescence spectroscopy.

• Fashion & Textile Research Journal
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• v.25 no.1
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• pp.24-40
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• 2023

Contemporary consumers' acceptance of second-hand products has been increasingly improving worldwide, especially in China. Based on the Extended Unified Theory of Acceptance and Use of Technology, we developed and empirically validated a research framework to predict consumers' motivation to use re-commerce platforms. We explored the diverse factors influencing mobile commerce usage through re-commerce platforms. Furthermore, this study investigated the role of gender differences as a factor moderating the association between several constructs and the intention to use re-commerce platforms. A total of 226 consumer responses were collected. The results indicated that hedonic motivation, performance expectancy, consumer habits, social influence, and price value affect consumers' attitudes toward re-commerce platforms. The effects of the attitude toward re-commerce platforms on the intention to use these platforms were also statistically significant. When effort expectancy, hedonic motivation, and consumer habits in re-commerce platform usage increase, male consumers' attitude toward its usage, in particular, also increases. Meanwhile, when performance expectancy, hedonic motivation, and consumer habits in re-commerce platform usage increase, the attitude toward its usage increases among female consumers. Moreover, our results indicate that the two gender groups present different characteristics regarding re-commerce platform usage. Therefore, this study offers a theoretical basis for future analyses of second-hand trade.

• Journal of Soil and Groundwater Environment
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• v.28 no.spc
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• pp.18-39
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• 2023

Rapid development of geophysical exploration and hydrogeologic monitoring techniques has yielded remarkable increase of datasets related to groundwater systems. Increased number of datasets contribute to understanding of general aquifer characteristics such as groundwater yield and flow, but understanding of complex heterogenous aquifers system is still a challenging task. Recently, applications of data science technique have become popular in the fields of geophysical explorations and monitoring, and such attempts are also extended in the groundwater field. This work reviewed current status and advancement in utilization of data science in groundwater field. The application of data science techniques facilitates effective and realistic analyses of aquifer system, and allows accurate prediction of aquifer system change in response to extreme climate events. Due to such benefits, data science techniques have become an effective tool to establish more sustainable groundwater management systems. It is expected that the techniques will further strengthen the theoretical framework in groundwater management to cope with upcoming challenges and limitations.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.12
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• pp.53-63
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• 1995

In the analysis of metal forming problems, the explicit time integration finite element method, which does not have convergence problems, is frequently used. The present work is to assess the applicability of the explicit time integration finite element method to quasi-static metal forming problems. Compressing analyses of thin-walled tubes and solid cylinders are performed with different loading velocities. The computed buckled profiles of thin walled tubes are compared with the theoretical and experimental ones and it is found that at sufficiently low loading velocity, the explicit time integration finite element method accurately predict quasi-static buckled profiles. When loading volocity is increased, the computed buckled profiles of thin-walled tubes are very sensitive to loading velocity however the computed profiles of solid cylinders are less sensitive to loading velocity. In orther words, the geometrically self-constrained specimens like solid cylinders are less sensitive to loading velocity than the geometrically unconstrained specimens like thin-walled tubes. As a result, it is found that the geometrically self-constrained problems which include the greater part of metal forming problems can be efficiently analyzed with loading velocity control technique.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.1
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• pp.87-94
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• 2010

This study mainly focused on the subsurface settlement due to shallow and deep tunneling in sandy ground. In order to figure out theoretical deformation patterns in association with the ground loss during the progress of tunneling, laboratory model tests using aluminum rods and finite element analyses using the CRISP program were carried out. As a result of comparison between the model test and the finite element analysis, the similar deformation patterns were found. In addition, it was identified that the most K values obtained from both the FEA and the model tests were distributed between Dyer et al. (1996) and Moh et al. (1996) of the field observation data. Based on the model test data, the linear equation of K for the sandy soil could be obtained.

• Structural Engineering and Mechanics
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• v.84 no.4
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• pp.517-530
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• 2022

In re-assessing the Jacket-type fixed steel structures, the current standards often allow the simplicity of corrosion sections using local buckling or equivalent section approach to applying empirical formulae of frame stress and resistance analyses. However, those approaches can lead to significant errors for non-uniform corroded frames in a specific area, including force distribution, stress, and allowable strength of the tubular section, compared to the actual cases. This paper investigates a suitable approach to determine the actual stress on non-uniform corroded tubular frames under compression through the non-linear ABAQUS model by considering the effect of large deformation on the frame axis and the frame section. There are 3 scenarios of interest. In the 1st and 2nd scenarios with simple corrosion cases, the stress ratios using the numerical model and theoretical formulae correspond to the calculation of allowable strength reduction ratios in standards. However, scenario 3, which describes non-uniform corroded sections based on survey data, provides considerable differences in results. Therefore, it proves the reliable and effective results when using this method to analyze the resistance of the actual corroded section in the Jacket platforms.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.328-332
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• 2015

By logging position data from GPS-equipped construction machines, we re-create daily activities as 3D animations to analyze performance and facilitate look-ahead scheduling. The 3D animation enables going back to any point in time and space to observe the activities as they took place. By segmenting data into a set of activities, it is possible to obtain actual measures of performance such as cycle times, production, speed profiles and idle times. The measures of performance can then be compared to those expected (e.g., theoretical speed profiles vs. observed profiles), and instances of significant difference can be flagged for further investigation. Idle times and queues that exceed prescribed thresholds can also be identified. In general, many of the traditional real-time performance analyses can be performed after the fact. Situations of interest can be identified automatically and the events in this manner enhances effective performance improvement in construction. The proposed research is explained and demonstrated using a real push-loaded earthmoving operation.

• Research in Mathematical Education
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• v.26 no.4
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• pp.333-349
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• 2023

Recently, AI has become a crucial tool in mathematics education due to advances in machine learning and deep learning. Considering the importance of AI, examining teachers' beliefs about AI in mathematics education (AIME) is crucial, as these beliefs affect their instruction and student learning experiences. The present study developed a scale to measure preservice teachers' (PST) beliefs about AIME through factor analysis and rigorous reliability and validity analyses. The study analyzed 202 PST's data and developed a scale comprising three factors and 11 items. The first factor gauges PSTs' beliefs regarding their roles in using AI for mathematics education (4 items), the second factor assesses PSTs' beliefs about using AI for mathematics teaching (3 items), and the third factor explores PSTs' beliefs about AI for mathematics learning (4 items). Moreover, the outcomes of confirmatory factor analysis affirm that the three-factor model outperforms other models (a one-factor or a two-factor model). These findings are in line with previous scales examining mathematics teacher beliefs, reinforcing the notion that such beliefs are multifaceted and developed through diverse experiences. Descriptive analysis reveals that overall PSTs exhibit positive beliefs about AIME. However, they show relatively lower levels of beliefs about their roles in using AI for mathematics education. Practical and theoretical implications are discussed.

• Asia Marketing Journal
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• v.25 no.3
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• pp.126-147
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• 2023

This study investigates the effects of the fulfillment of self-motivation including self-development, self-therapy, and self-presentation on the outcomes such as subjective quality of life, omnivorous cultural engagement, and visitor loyalty via visitor satisfaction in art museums. The analyses on 285 valid survey responses demonstrated that fulfillment of self-development and self-therapy needs have significant positive influence on visitor satisfaction. The effect of fulfilling self-presentation need on visitor satisfaction was found to be moderated by attitude toward SNS posting, while the age factor, based on generations, did not show a significant moderation effect. It was also found that visitor satisfaction positively influences visitor loyalty, including intentions of revisit and recommendation. Increased satisfaction also enhances subjective QOL and omnivorous cultural engagement among art museum visitors, implying promising collaboration among cultural arts institutions. The findings have both theoretical and practical implications for enhancing visitor experiences and promoting diverse cultural engagement. Limitations and future research directions are also discussed.

• Korea Trade Review
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• v.47 no.6
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• pp.307-333
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• 2022

In recent years, the outward foreign direct investment (oFDI) in the Belt and Road Initiative (BRI) by Chinese companies has significantly increased in size and changed in content. However, changes in the oFDI patterns between the pre- and post-BRI periods have not received sufficient attention from academia despite their theoretical and strategic significance. This paper reviewed existing research to establish seven hypotheses on changes in the oFDI patterns of Chinese companies investing in BRI countries and conducted empirical analyses to test the hypotheses using secondary data. The results showed that after the BRI agreement, Chinese oFDI in BRI countries was more active in less economically and less institutionally developed countries, that the oFDI by privately-owned enterprises (POEs) increased more than that of state-owned enterprises (SOEs), and that SOEs were more active in the social overhead capital (SOC) area while POEs were more active in the non-SOC area. The paper concludes with a summary, implications, and future research directions.