• Journal of Korea Port Economic Association
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• v.40 no.2
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• pp.157-173
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• 2024

This study analyzed the connectivity of the dry bulk carrier market before and after COVID-19 to examine the impact of COVID-19 on the global shipping market. Using the Quantile Time Frequency Connectedness methodology, we analyzed the dynamic connectedness of major dry bulk indices: the Capesize Index (BCI), Supramax Index (BSI), Panamax Index (BPI), and Handysize Index (BHSI). The results are as follows. First, the total spillover connectedness of the dry bulk carrier market increased during the entire period and in the short term after the outbreak of COVID-19, while it slightly decreased in the long term. Second, the roles among the indices changed according to market conditions, with COVID-19 causing the BPI to change from a net receiver to a net transmitter in the short term and the BSI in the long term, affecting net spillover connectedness. Third, it was observed that long-term connectivity tended to increase more than short-term connectedness under extreme conditions. Fourth, the phenomenon of strengthened connectedness under extreme market conditions was confirmed. These results provide important insights into understanding short-term market shocks and long-term stability trends, demonstrating that the connectedness among dry bulk carrier markets strengthens in global crisis situations such as COVID-19. This provides a basis for assessing the resilience and vulnerability of the shipping market and offers useful information for investors and policymakers in crisis management and investment strategy formulation.

• Journal of Korea Port Economic Association
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• v.39 no.4
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• pp.269-283
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• 2023

Based on daily data from January 4, 2016 to September 27, 2022, the impact of extreme movements of BDI on shipping companies' network connectivity was analyzed using CoVaR network connectivity. The main results and policy implications are as follows. First, according to the copula model results, the Student-t copula was selected as the most suitable model for COSCO, HMM, HRAG, MAERSK, and WAN. EVER was selected as a time-varying Gumbel copula, and YANG was selected as a time-varying rotated-Gumbel copula. Second, as a result of analysis using the TVP-VAR model, the linkage between shipping companies tended to increase when the BDI turned into an extreme risk state. In the comparison of net connectivity, the roles of COSCO and EVER changed. In addition, in the analysis of net pairwise connectivity, it was found that the change in the extreme risk state of BDI also affected the connectivity of shipping companies. In particular, EVER, WAN, and COSCO showed large changes. Taken together, the extreme fluctuations in BDI changed the role of Asian shipping companies, intensifying competition among shipping companies and strengthening risk delivery. It was confirmed that BDI has a great influence on the network connectivity of shipping companies and has an important influence on the stability of the stock market network. Therefore, the results of this study should consider not only the connectivity of shipping companies according to market conditions, but also the connectivity in extreme situations.

• Journal of Industrial Convergence
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• v.22 no.8
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• pp.95-103
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• 2024

In this study, the size of the influence of each factor was verified by step-by-step input of the family-friendly system, procedural fairness of the boss, and welfare benefits in the influence on the work-family balance of female managers. In order to achieve the purpose of the study, it was analyzed using the data of the panel survey of female managers surveyed by the Korea Women's Policy Institute in 2022. Among the 4,058 respondents in this data, 2,069 women who were female and had a spouse were extracted, and a total of 1,814 female managers were selected as the final study targets by removing missing values, outliers, and weights. The SPSS WIN 25.0 program was used to verify the influence between the measurement variables. As a result of the analysis, the family-friendly system, the procedural fairness of the boss, and welfare benefits had a positive effect on the work-family balance of female managers. In addition, as a result of step-by-step input of independent variables on the effect of work-family balance, the influence of the family-friendly system decreased, but it had the highest influence compared to other variables. Based on the results of this study, the necessity of intervention in social welfare practice to improve work-family balance of female managers was proposed.

• Journal of Bio-Environment Control
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• v.33 no.2
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• pp.107-113
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• 2024

For efficient soil water management in open fields, the proper use of soil moisture sensors is a prerequisite. Particularly in open-field environments like orchards with extensive root systems, the appropriate positioning of sensors is very important. The present study was conducted to identify the optimal placement of soil moisture sensors by assessing changes in soil water potential across various positions within orchard field soils after installing tensiometers. In apple and Asian pear orchards located in two regions of Korea, nine soil water potential sensors (TEROS 21, METER Group) were installed at distances of 20, 40, and 60 cm from the tree trunk and depths of 10, 20, and 30 cm from the soil surface, and monitored the soil water potential changes over two years. Results indicated that the positions closer to the tree trunk and the soil surface exhibited more pronounced changes in soil water potential. The greatest magnitude of change in soil water potential was observed at a distance of 20 cm and a depth of 10 cm, suggesting this position as the most suitable for soil moisture sensor installation. However, variations in the degree and pattern of changes in soil water potential were noted across sensor positions due to root system growth over time. Therefore, periodic observation and adjustments in sensor placement would be advisable to accurately monitor the soil moisture condition in long-term crops such as fruit trees in open fields.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.19 no.4
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• pp.29-40
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• 2024

This study analyzed the impact of venture companies' innovation capabilities on business performance by growth stage. Innovation capability, which is an independent variable, is composed of entrepreneur characteristics, technology development capabilities, marketing capabilities, and external cooperation. And the dependent variables were set as sales and long-term growth prospects. This study utilized data from the '2022 Precise Survey on Venture Companies'and conducted descriptive statistics analysis, correlation analysis, and multiple regression analysis as research methodology. As a result of the analysis, the negative influence of the educational background of entrepreneurs' characteristics was found to decrease as the growth stage increased, and the long-term growth prospects of entrepreneurs with abundant industrial practical experience were perceived positively. Research and development personnel was a negative factor during the start-up period, but as the growth stage increased and technology accumulation occurred, it changed into a positive factor. Marketing competency level was found to be an important factor in all growth stages. For external collaboration activities, all hypotheses regarding sales were rejected, but hypotheses regarding the start-up and growth periods regarding long-term growth prospects were accepted. it is interpreted that external collaboration activities are necessary to overcome the limitations of internal resources.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.5
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• pp.173-191
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• 2024

This study aims to investigate the impact of the leadership styles of organizations on the organizational commitment of instructors dispatched to social welfare facilities. To achieve this, a survey was conducted with 253 instructors working in welfare facilities, and the results were analyzed using SPSS 22.0. The analysis included frequency analysis, reliability and validity testing, correlation analysis, hypothesis testing, and mediation effect analysis. The findings of this study are as follows: First, servant leadership significantly affected organizational commitment, job satisfaction, and mindfulness. Second, transactional leadership had a significant impact on organizational commitment but did not significantly influence job satisfaction or mindfulness. Third, both mindfulness and job satisfaction were found to significantly affect organizational commitment. Fourth, there was a significant relationship between mindfulness and job satisfaction. These results suggest that leaders who exhibit servant leadership in organizations where dispatched instructors work have a more meaningful impact on increasing the instructors' organizational commitment compared to leaders who display transactional leadership, which may help reduce turnover rates. Additionally, the job satisfaction and mindfulness of dispatched instructors were found to influence organizational commitment, contributing to lower turnover rates and encouraging long-term employment. The mutual influence between job satisfaction and mindfulness enhances the self-efficacy of dispatched instructors, which in turn improves the quality of instruction, positively impacting young children and the elderly. This study sets servant leadership and transactional leadership as independent variables affecting organizational commitment, while examining the mediating roles of job satisfaction and mindfulness. The findings provide foundational data for enhancing organizational commitment among dispatched instructors, reducing turnover, and promoting long-term retention.

• Clean Technology
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• v.30 no.3
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• pp.228-238
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• 2024

Electrolytes are one of the essential components of a lithium-ion battery. They determine the battery's lifespan and cell characteristics. The dielectric constant is a key thermophysical property for determining how much salt can be dissociated and solvated in a solution. Hence, fast and reliable dielectric constant measurement is essential when formulating an electrolyte solution. This work implemented an open-ended coaxial probe (OECP) station as a quick and reliable tool to measure the complex permittivity spectra of electrolyte solutions. The capability of the OECP station was tested by measuring the complex permittivity of propylene carbonate (PC), dimethyl carbonate (DMC), and their mixtures from 0.1 to 8 GHz at 288.15, 298.15, and 308.15 K. The obtained dielectric spectra were then interpreted based on dielectric relaxation models and thermodynamic theories. The measured static dielectric constant data agreed well with the data from previous studies. They were also correlated using the Wang-Anderko thermodynamic model, showing approximately a 1% deviation from the experimental data. In addition, the relaxation characteristics, including the relaxation time and the Cole-Davidson exponent, showed that the microstructure of the solution significantly changes at the propylene carbonate mole fraction of 0.4. These results and methodologies are expected to contribute to the further understanding of electrolyte solutions and ultimately lead to the optimization of electrolyte formulation for lithium-ion batteries.

• Knowledge Management Research
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• v.25 no.3
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• pp.73-98
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• 2024

Chatbots are becoming increasingly popular as interactive communication tools that provide not only convenience but also a friendly and humanized experience. Due to the interactive nature of chatbots, they can exchange information with users to perform various tasks, and users sometimes intentionally provide inaccurate information. Considering social presence of conversational agents, perceived risk of providing personal information, and trust in algorithms as key influencing factors, this study explores the effects of those factors on the intention to provide inaccurate information in the context of online dating services and examine whether these effects vary across types of conversational agents. We conducted an analysis of structural equation model using data collected from Amazon Mechanical Turk (MTurk). The analysis results showed significant relationships between factors related to the intention to provide inaccurate information and empirically confirmed that those relationships vary by types of conversational agents. Out findings have academic implications for the behavior of providing inaccurate information in online environments and practical implications for designing chatbots to reduce such intentions. We also discuss the ethical implications of the consequences of inaccurate information online.

• The Journal of Engineering Geology
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• v.34 no.3
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• pp.447-457
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• 2024

This study investigated a cut-slope surface containing Tertiary faults, representing a conical-shaped slope with strike varying from N44°E to NS, N50°W, and finally N70°E. The slope consists mainly of basalt, with discontinuities in the slope including faults, fault zones, fracture zones, shear joints, and extension joints. The type and scale of failure vary with the strike of the slope and the strikes of discontinuities, with plane and wedge failure predominating. Based on face-mapping data, SMR (slope mass rating), rock physical and mechanical properties, analysis of stereonet projections and geological cross-sections, and critical equilibrium analysis, optimal slope stability determination was found to involve the countermeasure method, the slope gradient relief method, the green soil surface treatment method, and a fall prevention measure. After application of the countermeasure method, both dry and wet slope conditions exceeded allowable safety factors. It is expected that the preparation of geological cross-sections of various representative sections perpendicular to the surface of the slope, and the application of corresponding countermeasure methods, will be reasonable tools for three-dimensional analysis of slope stability. If the strike of the slope varies widely, it is necessary to prepare geological cross-sections, and the section used for critical equilibrium analysis must be established as the basic section.

• Korean Journal of Mineralogy and Petrology
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• v.37 no.2
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• pp.59-66
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• 2024

This study aimed to understand the mineral characteristics of the sediment from the summit of Magellan Seamount KC-7. In December 2023, approximately 20 years after the Korea Institute of Ocean Science and Technology conducted an initial field investigation of the sediment from the summit of seamount KC-7 in 2004, were obtained and subjected to mineralogical analysis to determine the essential sedimentary environmental characteristics of the seamount summit. For this purpose, smear slide analysis through a polarized microscope and X-ray diffraction analysis were conducted. The total length of the obtained sediments was 672.7 cm, and they were generally composed of calcareous ooze. In the lower part of the sediments (283.7-672.7 cm), Discoaster groups and coccoliths were predominantly observed. However, in the upper part above 283.7 cm, both coccoliths and foraminifera began to appear together, and in the uppermost sediments (0-151.7 cm), foraminifera became dominant, and the grain size of the sediments increased. This reflects a shift in the marine environment from high temperature and eutrophic conditions to low temperature and oligotrophic conditions as the seamount moved to its current position, aligning with the present oligotrophic environment of the western Pacific. The sediments comprised clay minerals, quartz, feldspar, and calcite. Examining the content changes of the four major mineral groups with depth, calcite was the most predominant, averaging 89.8 wt%. However, towards the upper layers, there was a trend of increasing clay content (up to 12.1 wt%) and decreasing calcite content (down to 85.1 wt%). This indicates that while the sedimentation mechanism remained unchanged, there has been a gradual influx of aeolian sediments.