• Journal of Venture Innovation
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• v.6 no.2
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• pp.159-172
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• 2023

This study aimed to empirically analyze the factors influencing the career search intention of college students. The research model was derived based on the Social Cognitive Career Theory (SCCT), considering the unique characteristics of university students. Self-efficacy and outcome expectations were investigated as independent variables, while mastery experience, verbal persuasion, vicarious learning, and positive emotions were considered as antecedent variables. A survey was conducted among college students in the metropolitan area, resulting in 217 valid responses for analysis. Empirical analysis was conducted using structural equation modeling with AMOS 24. The findings revealed that mastery experience, vicarious learning, and positive emotions had a significant positive effect on self-efficacy. Furthermore, verbal persuasion and positive emotions significantly influenced outcome expectations. However, the impact of verbal persuasion on self-efficacy was not found to be significant, and the relationship between mastery experience, vicarious learning, and outcome expectations was not examined. Both self-efficacy and outcome expectations were found to have a significant positive effect on career search intention, with outcome expectations exhibiting a stronger influence. The empirical results contribute to the understanding of college students' career exploration and provide implications for academic and practical contexts.

• Clean Technology
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• v.29 no.4
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• pp.327-332
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• 2023

This study investigated synthesis gas production via steam reforming of biogas. Ni-Al₂O₃ and Ni-CeO₂ catalysts were synthesized using the co-precipitation method, with controlled precipitation agent injection rates. Catalytic performances were tested at various temperatures, with a gas composition ratio of CH₄:CO₂:H₂O = 1:0.67:3 and a gas hourly space velocity (GHSV) of 647,000 mL h^-1 gcat^-1. The rate of precipitation agent injection influenced the characteristics of the catalysts depending on the type of support used. As the temperature increased, both the CO₂ reforming of methane and the reverse water gas shift reactions occurred. The Ni-Al₂O₃ catalyst, synthesized with a single injection of the precipitation agent, exhibited the best catalytic activity under conditions with sufficient steam supply among the prepared catalysts, due to its high Ni dispersion.

• Clean Technology
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• v.29 no.4
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• pp.297-304
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• 2023

The rapid advancement of the high-tech electronics industry has led to a significant increase in high-concentration ammonia wastewater. Various methods have been attempted to reliably treat wastewater containing high concentrations of ammonia, but no successful technology has yet been developed and applied. In this study, the removal efficiency and characteristics of ammonia nitrogen was evaluated according to changes in temperature, air loading rate, and liquid loading rate using a closed circulation countercurrent packed tower type demonstration facility for wastewater containing high concentrations of ammonia generated in the high-tech electronics industry. The temperature was varied while maintaining operating conditions of a wastewater flowrate of 20.8 m³ h^-1 and an air flow rate of 18,000 Nm³ h^-1. The results showed that at temperatures of 45,50,55, and 60℃, the removal efficiencies of ammonia nitrogen (NH₃-N) were 87.5%, 93.4%, 96.8%, and 98.7%, respectively. It was observed that temperature had the most significant impact on the removal efficiency of NH₃-N under these conditions. As the air loading rate increases, the removal rate also increases, but the increase in removal efficiency is not significant because droplets from the absorption tower flow into the stripping tower. Even if the liquid loading rate was changed by ±30%, the removal rate did not change significantly. This does not mean that the removal rate was unaffected, but was believed to be due to the relatively high air load rate. Through demonstration research, it was confirmed that ammonia stripping is a reliable technology that can stably treat high-concentration ammonia wastewater generated in the high-tech electronics industry.

• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.483-490
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• 2022

Floating LiDAR is a system that provides a new paradigm for wind condition observation, which is essential when creating an offshore wind farm. As it can save time and money, minimize environmental impact, and even reduce backlash from local communities, it is emerging as the industry standard. However, the design and verification of a stable platform is very important, as disturbance factors caused by fluctuations of the buoy affect the reliability of observation data. In Korea, due to the nation's late entry into the technology, a number of foreign equipment manufacturers are dominating the domestic market. The west coast of Korea is a shallow sea environment with a very large tidal difference, so strong currents repeatedly appear depending on the region, and waves of strong energy that differ by season are formed. This paper conducted a study examining buoys suitable for LiDAR operation in the waters of Korea, which have such complex environmental characteristics. In this paper, we will introduce examples of optimized design and verification of ship-type buoys, which were applied first, and derive important concepts that will serve as the basis for the development of various platforms in the future.

• Journal of the Korean Association of Geographic Information Studies
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• v.26 no.4
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• pp.145-160
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• 2023

The purpose of this study was to compare and analyze diurnal thermal environments using Unmanned Aerial Vehicles(UAV)-derived physical parameters(NDVI, SVF) and ENVI-met modeling. The research findings revealed significant correlations, with a significance level of 1%, between UAV-derived NDVI, SVF, and thermal environment elements such as S↑, S↓, L↓, L↑, Land Surface Temperature(LST), and Tmrt. In particular, NDVI showed a strong negative correlation with S↑, reaching a minimum of -0.52^** at 12:00, and exhibited a positive correlation of 0.53^** or higher with L↓ at all times. A significant negative correlation of -0.61^** with LST was observed at 13:00, suggesting the high relevance of NDVI to long-wavelength radiation. Regarding SVF, the results showed a strong relationship with long-wave radiative flux, depending on the SVF range. These research findings offer an integrated approach to evaluating thermal comfort and microclimates in urban areas. Furthermore, they can be applied to understand the impact of urban design and landscape characteristics on pedestrian thermal comfort.

• Journal of Korea Water Resources Association
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• v.56 no.12
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• pp.905-918
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• 2023

This study aimed to assess runoff reduction performance and determine installation priorities for Permeable Pavement (PP) and Rain Barrel (RB) within the Mokgam Stream basin. Optimal design parameters were determined to maximize the effectiveness of PP and RB in reducing runoff. Furthermore, the optimal parameters were incorporated to compare the runoff reduction performance of PP and RB. Analysis of the runoff curve at the basin outlet indicated that PP demonstrated superior performance in reducing runoff during the rising limb of the curve. At the same time, RB excelled within the falling limb. Comparisons of total runoff and peak runoff reduction by sub-catchment revealed that in larger sub-catchment areas, PP outperformed RB in runoff reduction. In contrast, RB exhibited higher performance in areas with a higher impervious ratio. Based on the evaluation of runoff reduction performance for PP and RB, installation priorities were determined within the Mokgam Stream basin. The results showed that PP and RB installations were prioritized for sub-catchments with larger areas and a higher impervious ratio. Furthermore, the correlation between the ranking of runoff reduction performance and sub-catchment characteristics showed a high correlation with both the impervious area ratio and sub-catchment geometrical properties in sub-watersheds exhibiting the top 25% runoff reduction performance. These results emphasize that when determining the priority for installing LID facilities in developed urban areas, it is necessary to consider not only the impervious area ratio but also the geometrical properties of the sub-catchment.

• Journal of the Korea Institute of Building Construction
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• v.23 no.6
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• pp.663-671
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• 2023

This research experimentally evaluated the recyclability of four varieties of lignocellulosic fly ash(FA), a by-product from three power plants employing lignocellulosic biomass(Bio-SRF, wood pellets) as a fuel source. Comprehensive analyses were conducted on FA, encompassing both physical parameters (particle shape, size distribution, fineness, and density) and chemical properties(chemical composition and heavy metal content). Mortar test specimens, with FA mixing ratios ranging from 5 to 20%, were produced in compliance with KS L 5405 standards, and their flow and compressive strength were subsequently measured. The test results indicated that the four types of FA exhibited particle sizes approximately between 20~30㎛, densities around 2.3~2.5g/cm³, and a fineness range of 2,600~4,900cm²/g. The FA comprised approximately 50~90% of components such as SiO₂, Al₂O₃, Fe₂O₃, and CaO, displaying characteristics akin to type-II and type-III FA of KS L 5405 standards, albeit with differences in chlorine and SiO₂ content. From the mortar tests, it was observed that the compressive strength of the mortar ranged between 34~47MPa when the pellet combustion FA was mixed in proportions of 5~20%. FA, produced exclusively from the combustion of 100% lignocellulosic fuel, is assessed to possess high recyclability potential as a substitute for conventional admixtures.

• Journal of the Korean Institute of Landscape Architecture
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• v.52 no.1
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• pp.87-100
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• 2024

This study aimed to investigate the impact of the quality of the street environment in residential areas on the mental health of urban residents, considering the frequency of street use. Using a zero-inflated negative binomial regression model, the study analyzed the influence of walking frequency and the street environment on depressive symptoms of urban residents. The research focused on Seoul, South Korea, in 2017, with depressive symptoms as the dependent variable and street environment variables, walking variables, and individual characteristics as independent variables. Additionally, the study explores the interaction effect of street greenery and walking frequency to analyze the synergistic impacts of walking in green spaces on mental health. The findings indicate that a higher ratio of street green areas is associated with fewer depressive symptoms. Increased walking frequency is linked to a reduction in depressive symptoms or a weaker manifestation of such symptoms. The interaction effect confirms that more frequent walking in green spaces is associated with weaker depressive symptoms. Lower ratios of visual complexity are correlated with reduced depressive symptoms. This study contributes to addressing urban residents' mental health issues at the community level by emphasizing the importance of the street green environment in residential areas.

• Information Systems Review
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• v.24 no.4
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• pp.77-96
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• 2022

Live commerce has recently received substantial attention due to the spread of the non-face-to-face consumption culture driven by the COVID-19 pandemic. Live commerce has a higher purchase conversion rate than other forms of commerce. Accordingly, the likelihood of impulse buying in a live commerce environment is expected to be high. However, there is a shortage of research on consumer impulse buying in the live commerce environment. This study designs a scenario-based experiment using the integrated model of consumption impulse formation and enactment. Through this method, this study validates the influence of the characteristics of live commerce (i.e., vicarious experience and real-time interaction) on consumers' likelihood of impulse buying and further examines the moderating role of a live commerce host feature (i.e., professionalism) in these relationships. The results of this study confirm that both vicarious experience and real-time interaction have a positive effect on consumers' likelihood of impulse buying and that professionalism strengthens the impact of vicarious experience on the likelihood of impulse buying. This study's scenario-based experimental design is meaningful because it analyzes the likelihood of impulse buying in the context of live commerce shopping. Additionally, it provides live commerce service and platform providers with practical insights into how to maximize profits and operate services more efficiently.

• Korean Journal of Radiology
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• v.22 no.4
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• pp.652-662
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• 2021

Objective: To investigate the association between CT imaging features and survival outcomes in patients with primary invasive mucinous adenocarcinoma (IMA). Materials and Methods: Preoperative CT image findings were consecutively evaluated in 317 patients with resected IMA from January 2011 to December 2015. The association between CT features and long-term survival were assessed by univariate analysis. The independent prognostic factors were identified by the multivariate Cox regression analyses. The survival comparison of IMA patients was investigated using the Kaplan-Meier method and propensity scores. Furthermore, the prognostic impact of CT features was assessed based on different imaging subtypes, and the results were adjusted using the Bonferroni method. Results: The median follow-up time was 52.8 months; the 5-year disease-free survival (DFS) and overall survival rates of resected IMAs were 68.5% and 77.6%, respectively. The univariate analyses of all IMA patients demonstrated that 15 CT imaging features, in addition to the clinicopathologic characteristics, significantly correlated with the recurrence or death of IMA patients. The multivariable analysis revealed that five of them, including imaging subtype (p = 0.002), spiculation (p < 0.001), tumor density (p = 0.008), air bronchogram (p < 0.001), emphysema (p < 0.001), and location (p = 0.029) were independent prognostic factors. The subgroup analysis demonstrated that pneumonic-type IMA had a significantly worse prognosis than solitary-type IMA. Moreover, for solitary-type IMAs, the most independent CT imaging biomarkers were air bronchogram and emphysema with an adjusted p value less than 0.05; for pneumonic-type IMA, the tumors with mixed consolidation and ground-glass opacity were associated with a longer DFS (adjusted p = 0.012). Conclusion: CT imaging features characteristic of IMA may provide prognostic information and individual risk assessment in addition to the recognized clinical predictors.