• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1395-1406
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• 2022

This study investigated the effects of the urban forest and street trees on flow and temperature distribution in the Daegu National Debt Redemption Movement Memorial Park. For this, we implemented tree-drag and tree-cooling parameterization schemes in a computational fluid dynamics (CFD) model and validated the simulated wind speeds, wind directions, and air temperatures against the measured ones. We used the wind speeds, wind directions, air temperatures predicted by the local data assimilation and prediction system (LDAPS) as the inflow boundary conditions. To investigate the flow and thermal characteristics in the presence of trees in the target area, we conducted numerical experiments in the absence and presence of trees. In the absence of trees, strong winds and monotonous flows were formed inside the park, because there were no obstacles inducing friction. The temperature was inversely proportional to the wind speed. In the presence of trees, the wind speeds(temperatures) were reduced by more than 40 (5)% inside the park with a high planting density due to the tree drag (cooling) effect, and those also affected the wind speeds and temperatures outside the park. Even near the roadside, the wind speeds and temperatures were generally reduced by the trees, but the wind speeds and air temperatures increased partly due to the change in the flow pattern caused by tree drag.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1207-1217
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• 2022

Vegetation indices using the reflectance of selected wavelength, associating with the monitoring purpose such as identifying the progress of crop growth, on the vegetation canopy surface is widely used in the digital agriculture technology. However, the surface reflectance anisotropy can distort the true value of vegetation index related to the condition of surface, even though the surface property be unchanged. That causes difficulty to observe accurately crop growth on the monitoring system. In this study, a simple type goniometer was designed to measure the reflectance from the anisotropic surface according to various zeniths and azimuths of sun and viewing sensor in the field. On the tarp like as Lambertian surface, the reflectance of Blue, Green, Red, Near-Infrared band was similar to the tarps' reflectance properties. However, the reflectance was slightly overestimated in the cloudy day. The relative difference values of vegetation indices on grass were overestimated for the forward viewing and underestimated for the backward viewing. In addition, enhanced vegetation index (EVI) showed less sensitive according to the positions of sun and sensor viewing. Field observation with a goniometer will be helpful to understand the anisotropy characteristics on the vegetation surface.

• Journal of Korea Port Economic Association
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• v.38 no.3
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• pp.151-164
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• 2022

According to the "2021 Trade Statistics" released by the Korea Customs Service, the number of domestic export companies has decreased by 2,400 since COVID-19, and the number of importers has increased by 10,000. Exporting companies are making a great contribution to the economic development of Korea along with the creation of domestic jobs. At a time when the logistics environment changes rapidly, there are insufficient papers analyzing the impact of eco-friendly logistics strategies of domestic exporters on logistics performance. In order for exporting companies to continue to have global competitiveness and improve logistics performance, it is necessary to analyze the impact of eco-friendly logistics strategies on the logistics performance of exporting companies. The purpose of this study is to analyze the effect of eco-friendly logistics strategies of domestic export companies on logistics performance. The eco-friendly logistics strategy is divided into an internal strategy and a supply chain management strategy. As a result of the analysis, it was analyzed that the internal strategy has a positive effect on the logistics performance of exporting companies, and the supply chain management strategy has a positive effect on the logistics performance of exporting companies. As such, it was analyzed that the eco-friendly logistics strategy of exporting companies is an important resource for companies and serves as the basis for improving the logistics performance of companies.

• Journal of Practical Engineering Education
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• v.13 no.3
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• pp.473-482
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• 2021

This study attempted to provide basic data for career counseling and education programs by verifying the mediating effect of career decision-making self-efficacy on relationship between perceived social support and career preparation behavior of Korean Polytechnics students. A total of 314 students from 11 departments attending the I Campus of Korea Polytechnics II were surveyed, and the research results are as follows. First, it was found that career decision-making self-efficacy completely mediated the relationship between social support and career preparation behavior. Second, the career decision-making self-efficacy had complete mediating effects on the relation between social support and career preparation behavior. Third, it was found that social support indirectly had a positive effect on career preparation behavior through career decision-making self-efficacy. The results of this study show that perceived social support of Korean Polytechnics students affects career decision-making self-efficacy and increases the level of career preparation behavior. This suggests that through active social support around Korean Polytechnics students, it is necessary to provide environmental factors that can promote career preparation behavior by enhancing the self-efficacy of career decision-making, which is a low-level factor for students.

• Korean Journal of School Psychology
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• v.17 no.2
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• pp.181-198
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• 2020

This study examined how the rejection sensitivity model might be applied to the link between rejection sensitivity and dating relationship satisfaction by means of investigating the mediating effect of cognitive emotion regulation strategy and conflict resolution strategy. A total of 668 college students in Seoul (232 males, 436 females, mean age of 21.59 years [SD=2.08]) participated in this study. The results illustrated that the adaptive emotion regulation strategy, among cognitive emotion regulation strategies, and the integration and compromise strategies, among conflict resolution strategies, had the double mediation effect on the association between rejection sensitivity and dating relationship satisfaction. In other words, a direct negative correlation between rejection sensitivity and dating relationship satisfation resulted in high rejection sensitivity, which was expected to generate low satisfaction in dating relationships. However, it was confirmed that the use of these two strategies-the cognitive emotion regulation and the conflict resolution strategy-could bring positive effects in terms of the dating relationship satisfaction; the former helped couples to see situations more broadly and increase positive perceptions, while the latter solve their problems each other. Based on these findings, we discuss their implications for counseling practice and therapeutic interventions

• The Journal of the Korea Contents Association
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• v.22 no.1
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• pp.591-600
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• 2022

This study examined the participation of the people with stroke living in the community in terms of productivity, leisure, and social domain, and identified the effect on disability acceptance and anxiety. For data collection, from October 2018 to January 2019, data on disability acceptance, anxiety, and participation were collected from 192 people with stroke who used welfare centers and community services. For general characteristics, t-test and one-way ANOVA were used to compare participation according to descriptive statistics and general characteristics. Pearson correlation analysis was used for correlation between variables, and multiple regression analysis was used to identify causality. As the result, factors affecting the productivity of participation were labor(β=.28, p<.001), de-emphasis on disability salience(β=.14, p<.05), compensatory(β=.22, p<.01), and subjective anxiety(β=-.35, p<.05), and the explanatory power was 33%(F=9.44, p<.001). Leisure was expressed as self-satisfaction with disability(β=.18, p<.05) and the compensatory(β=.18, p<.05), and had an explanatory power of 23%(F=6.32, p<.001). Social activity was labor(β=.19, p<.01), and subjective anxiety(β=-.51, p<.05), which showed 23%(F=6.05, p<.001) of explanatory power. This suggests the importance of psychosocial factors for a changed life after the onset of a stroke, and a practical approach is needed to construct and apply programs to improve participation.

• Economic and Environmental Geology
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• v.55 no.3
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• pp.219-229
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• 2022

Bentonite is being considered as a candidate for buffer material in geological disposal systems for high-level radioactive wastes. In this study, the effect of cement-bentonite interactions on bentonite alteration was investigated by reviewing the literature on studies of cement-bentonite interactions. The major bentonite alteration by hyperalkaline fluids produced by the interaction of cementitious materials with groundwater includes cation exchange, montmorillonite dissolution, secondary mineral precipitation, and illitization. When the hyperalkaline leachate from the reaction of the cementitious material with the groundwater comes into contact with bentonite, montmorillonite, the main component of bentonite, is dissolved and a small amount of secondary minerals such as zeolite, calcium silicate hydrate, and calcite is produced. When montmorillonite is continuously dissolved, the physicochemical properties of bentonite may change, which may ultimately causes changes in bentonite performance as a buffer material such as adsorption capacity, swelling capacity, and hydraulic conductivity. In addition, the bentonite alteration is affected by various factors such as temperature, reaction period, pressure, composition of pore water, bentonite constituent minerals, chemical composition of montmorillonite, and types of interlayer cations. This study can be used as basic information for the long-term stability verification study of the buffer material in the geological disposal system for high-level radioactive wastes.

• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.11-16
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• 2022

Metal-organic frameworks (MOFs) are porous materials with nano-sized pores. The degree of gas adsorption and pore size can be controlled according to types of metal ions and organic ligands. Many studies have been conducted on MOFs in the fields of gas storage and separation, and gas sensors. For rapid and quantitative gas adsorption/desorption analyses, it is necessary to form various MOF structures in uniform films on a sensor surface. In this review, some of representative direct methods for uniformly synthesizing MOFs such as MIL-53 (Al), ZIF-8, and Cu-BDC from anodized aluminum oxide, zinc oxide nanorods, and copper thin films, respectively on the surface of a microresonator are highlighted. In addition, the operation principle of quartz crystal microbalance and microcantilever, which are representative microresonators, and the interpretation of signals that change when gas is adsorbed to MOFs are covered. This is intended to enhance the understanding of gas adsorption/desorption analysis of MOFs using microresonators.

• The Journal of the Korea Contents Association
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• v.21 no.12
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• pp.95-106
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• 2021

The purpose of this study is to derive major topics in content R&D and provide directions for academic development by exploring research trends over the past 20 years using topic modeling targeting 9,858 papers published in the Journal of the Korean Contents Association. To secure the reliability and validity of the extracted topics, not only the quantitative evaluation technique but also the qualitative technique were applied step-by-step and repeated until a corpus of the level agreed upon by the researchers was generated, and detailed analysis procedures were presented accordingly. As a result of the analysis, 8 core topics were extracted. This shows that the Korean Contents Association is publishing convergence and complex research papers in various fields without limiting to a specific academic field. Also, before 2012, the proportion of topics in the field of engineering and technology appeared relatively high, while after 2012, the proportion of topics in the field of social sciences appeared relatively high. Specifically, the topic of 'social welfare' showed a fourfold increase in the second half compared to the first half. Through topic-specific trend analysis, we focused on the turning point in time at which the inflection point of the trend line appeared, explored the external variables that affected the research trend of the topic, and identified the relationship between the topic and the external variable. It is hoped that the results of this study can provide implications for active discussions in domestic content-related R&D and industrial fields.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.4
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• pp.20-29
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• 2022

The operational modal analysis (OMA) technique, which extracts the modal parameters of a structural system using ambient vibrations, has been actively developed as a field of structural health monitoring of cable-supported bridges. In this paper, the short and long-term modal parameters of a cable-stayed bridge were evaluated using the acceleration data obtained from the two ambient vibration tests (AVTs) and three years of continuous measurements. A total of 27 vertical modes and 1 lateral mode in the range 0.1 ~ 2.5 Hz were extracted from the high-resolution AVTs which were conducted in the 6th and 19th years after its completion. Existing OMA methods such as Peak-Picking (PP), Eigensystem Realization Algorithm with Data Correlation (ERADC), Frequency Domain Decomposition (FDD) and Time Domain Decomposition (TDD) were applied for modal parameters extraction, and it was confirmed that there was no significant difference between the applied methods. From the correlation analysis between long-term natural frequencies and environmental factors, it was confirmed that temperature change is the dominant factor influencing natural frequency fluctuations. It was revealed that the decreased natural frequencies of the bridge were not due to changes in structural performance and integrity, but to the environmental effects caused by the temperature difference between the two AVTs. In addition, when the TDD technique is applied, the accuracy of extracted mode shapes is improved by adding a proposed algorithm that normalizes the sequence so that the autocorrelations at zero lag equal 1.