• Journal of the Korean Geotechnical Society
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• v.39 no.12
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• pp.37-46
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• 2023

Dynamic soil properties are essential factors for predicting the detailed behavior of the ground. However, there are limitations to gathering soil samples and performing additional experiments. In this study, we used an artificial neural network (ANN) to predict dynamic soil properties based on static soil properties. The selected static soil properties were soil cohesion, internal friction angle, porosity, specific gravity, and uniaxial compressive strength, whereas the compressional and shear wave velocities were determined for the dynamic soil properties. The Levenberg-Marquardt and Bayesian regularization methods were used to enhance the reliability of the ANN results, and the reliability associated with each optimization method was compared. The accuracy of the ANN model was represented by the coefficient of determination, which was greater than 0.9 in the training and testing phases, indicating that the proposed ANN model exhibits high reliability. Further, the reliability of the output values was verified with new input data, and the results showed high accuracy.

• Journal of Industrial Convergence
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• v.21 no.12
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• pp.11-23
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• 2023

This study aims to investigate the relationship between service recovery justice, residual emotions, and customer behavior. It empirically verifies that low justice in service recovery affects residual emotions and, in turn, has an impact on customers' negative behaviors. Furthermore, this research distinguishes customer-brand relationship quality into emotional relationship quality and cognitive relationship quality and seeks to validate that the type of relationship quality may influence the extent to which the justice of recovery processes affects residual emotions. Data was collected through surveys, and hypotheses were tested using structural equation modeling. The research findings indicate that among the dimensions of service recovery justice, procedural justice and interactional justice significantly influence residual emotions. Moreover, residual emotions have a significant impact on both the intention to revisit and the intention to engage in negative word-of-mouth. In addition, the impact of distributive justice and procedural justice on residual emotions was found to be higher for cognitive relationship quality than emotional relationship quality, and the impact of interactional justice on residual emotions was found to be higher for emotional relationship quality than cognitive relationship quality.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.85-91
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• 2023

In this study, an experimental study was conducted on the flame behavior, combustion dynamics, and NOx emission characteristics for hydrogen co-firing with the EV burner which is the first stage combustor of GT24. It was confirmed that as the hydrogen co-firing rate increases, the NOx emission increases. This change was elucidate to be the result of a combination of changes in penetration depth due to changes in fuel density, reduction in fuel mixing due to changes in flame position due to increased flame propagation speed, and oscillation of fuel mixedness due to combustion instability. Through pressurization tests in the range of 1.3 to 3.1 bar, NOx emission characteristics under high-pressure operating conditions were predicted, and based on this, the hydrogen co-firing limits of the EV burner was evaluated.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.5
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• pp.109-121
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• 2023

This paper examines whether angel investors affect startup's financial performance (profitability and growth ratios) in the Korean startup market over 10 years period from 2009 to 2018. In particular, we consider not only the behavior of angel investor such as the investment amount or the type of investments (stocks, bonds) but also the type of angle investor (individual or corporation). Our empirical results are as follows. First, we find that the startup's profitability ratios are higher after the investment of angel investors. However, the growth ratios show different results in assets and sales. Second, we identify that the investment amount of angel investors negatively affects on the startup's growth ratios. Lastly, we find that equity investment such as common stock or preferred stock and the individual angel investors such as personal investment association or professional angels show higher financial performance than bond investment or corporate angel investors. Overall, our findings imply that angel investors positively affect startup's financial performance. In particular, we infer that the superior financial performance is largely attributed to monitor startups by participating as shareholders or to select more carefully by the individual angel investors who may be exposed to more investment risk. In conclusion, our findings support that angel investors play a positive role in the Korean venture investment market.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.3
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• pp.119-133
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• 2022

The COVID-19 pandemic is rapidly changing the behavior of members of society. Typically, the strong contagious power of the virus minimizes interaction between people in the real world, and they keep interaction activities to a minimum through online activities. Recently, as people demand online activities that enhance a sense of reality, the metaverse, which strengthens the 3D technology-centered sense of presence capability, is being chosen by people. The purpose of this study is to suggest a strategic direction for the establishment of the metaverse business model of startups by presenting factors for users' use and gratification of the metaverse. In detail, this study proposes the motivation for using the metaverse by reflecting the uses and gratification theory, and suggests a method to strengthen the motivation for the metaverse by reflecting the presences provided by the metaverse plotform and individual characteristics (normtive interpersonal influence). We surveyed people over 20 years of age who experienced metaverse and obtained 314 samples. In addition, we conducted the main effect analysis using the structural equation model and the moderating effect analysis using Process 3.1. As a result of hypothesis testing, we confirmed that metaverse presence (telepresence, social presence) has a positive effect on intention to continuous use by increasing metaverse's use and satisfaction factors (information, enjoyment, social interactivity). In addition, we found that individuals' normative interpersonal influence moderated the positive relationship between uses and gratification factors(enjoyment and social interactivity) intention to continuous use. Our study suggests strategies for establishing a user-centered business model for companies related to the metaverse.

• Korean Journal of Culture and Social Issue
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• v.30 no.1
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• pp.55-79
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• 2024

The purpose of this study is to conduct an exploratory investigation into Korean psychopathy by synthesizing the results of prior domestic research on the validation of psychopathy assessment tools. Domestic research on the validation of psychopathy scales has been constrained by limited research methodologies, bias toward male subjects, and the application of inappropriate factor structures. Furthermore, although discrepancies between the original scale and the Korean scale were identified regarding the factor structures through in construct validity research, discussion on the concept of Korean psychopathy has been limited. As a result, this study compared 16 domestic papers on the validation of psychopathy assessment tools along with 9 international foreign papers that addressed the factor structure of each original scale. By comparing the derived factor structures, items assigned to each factor, and omitted items from each study, the characteristics of Korean psychopathy were explored. The findings revealed that Korean psychopathy is recognizable from materialism, machiavellianism, and antisocial behavior and impulsivity. This study holds significance in synthesizing the outcomes of current domestic psychopathy validation research and offers a conceptual foundation to help understand Korean psychopathy.

• Health Policy and Management
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• v.34 no.1
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• pp.87-93
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• 2024

Background: In recent years, studies have shown conflicting results regarding the benefits of dietary supplements in reducing healthcare expenditures. This study aimed to address this inconsistency by examining the association between supplement consumption and health expenditures using nationally representative data from the Korea Health Panel Survey (2019-2020). Methods: A 1:1 matched case-control dataset was established using propensity score matching technique based on supplement consumption. Then, total annual healthcare expenditures were compared between the two groups. In addition, a multivariate regression analysis (Proc Surveyreg) was performed to determine the association between the supplement consumption and medical costs. Results: The supplement user group spent about 1.72 million Korean won, while the non-user group spent about 1.43 million Korean won on medical services (p=0.0186). The results of multivariate regression showed that the costs were approximately 26.15% higher in the user group than in the non-user group (p=0.0004). Conclusion: Contrary to the previous studies that have shown the benefits of supplement use in reducing healthcare costs, this study showed that those who consistently consumed supplements spent more on medical services. This can be interpreted in the same context as previous studies suggesting that dietary supplement intake is a healthy behavior for managing one's health. However, we caution against drawing firm conclusions due to data limitations. Further analysis using patient-level epidemiologic data is needed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.1
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• pp.82-96
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• 2024

While analyzing traffic flow, speed, traffic volume, and density are important macroscopic indicators, and acceleration and spacing are the important microscopic indicators. The speed and traffic volume can be collected with the currently installed traffic information collection devices. However, acceleration and spacing data are necessary for safety and autonomous driving but cannot be collected using the current traffic information collection devices. 'You Look Only Once'(YOLO), an object recognition technique, has excellent accuracy and real-time performance and is used in various fields, including the transportation field. In this study, to measure acceleration and spacing using YOLO, we developed a model that measures acceleration and spacing through changes in vehicle speed at each interval and the differences in the travel time between vehicles by setting the measurement intervals closely. It was confirmed that the range of acceleration and spacing is different depending on the traffic characteristics of each point, and a comparative analysis was performed according to the reference distance and screen angle to secure the measurement rate. The measurement interval was 20m, and the closer the angle was to a right angle, the higher the measurement rate. These results will contribute to the analysis of safety by intersection and the domestic vehicle behavior model.

• Journal of Industrial Convergence
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• v.22 no.2
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• pp.143-151
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• 2024

This study compared the health behaviors, health related clinical characteristics between individuals with Glycated Hemoglobin A1C≧6.5% and < 6.5% in 30~59yr. Factors that were associated with A1C were identified by sex, health behaviors, health literacy. This study was an observational study with a cross-sectional design based on data from 2019~2021 Korea National Health and Nutrition Examination Survey. Multiple logistic regression analysis was employed to compute the odds ratios of health behaviors to identify the risk factors for Glycated Hemoglobin. The prevalence of A1C≧6.5% among the total was 79.4%(weighted %, n=348). In the A1C≧6.5%, 71.8% were men. In univariate logistic regression for A1C≧6.5%, sex, duration with diabetes, and body mass index(BMI) were influencing factors. In multiple logistic regression by sex, the factors associated with A1C≧6.5 in women were as follows: education(OR 4.5; 95% CI:1.1, 18.5), duration with diabetes(OR 2.9; 95% CI 1.1, 7.9). Strategies should be targeted to improve health behaviors and clinical characteristics for those in their sex, women in low education level, duration with diabetes. Moreover, healthcare providers should understand the barriers to health behaviors and health literacy to effectively deliver healthcare service.

• Information Systems Review
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• v.23 no.4
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• pp.45-67
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• 2021

As the transaction volume of the C2C second-hand market is growing, the number of frauds, which intend to earn unfair gains by sending products different from specified ones or not sending them to buyers, is also increasing. This study explores the model that can identify frauds in the online C2C second-hand market by examining the postings for transactions. For this goal, this study collected 145,536 field data from actual C2C second-hand market. Then, the model is built with the characteristics from postings such as the topic and the linguistic characteristics of the product description, and the characteristics of products, postings, sellers, and transactions. The constructed model is then trained by the machine learning algorithm XGBoost. The final analysis results show that fraudulent postings have less information, which is also less specific, fewer nouns and images, a higher ratio of the number and white space, and a shorter length than genuine postings do. Also, while the genuine postings are focused on the product information for nouns, delivery information for verbs, and actions for adjectives, the fraudulent postings did not show those characteristics. This study shows that the various features can be extracted from postings written in C2C second-hand transactions and be used to construct an effective model for frauds. The proposed model can be also considered and applied for the other C2C platforms. Overall, the model proposed in this study can be expected to have positive effects on suppressing and preventing fraudulent behavior in online C2C markets.