• 한국노년학
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• v.41 no.3
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• pp.421-444
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• 2021

The purpose of this research is to examine the reciprocal relationships between depression and marital satisfaction among older couples. For longitudinal dyadic analysis, this study sets up a research model based on the Actor-Partner Interdependence Model, the Common Fate Model, and Autoregressive Cross-Lagged Model. Data came from four annual waves from the 10th year (2015) to the 13th year (2018) of the Korean Welfare Panel Survey and the final sample comprised a total of 1,383 married couples over 60 years of age in 2015. Structural Equation Modeling identified the reciprocal relationship between depression and marital satisfaction among older couples, with higher marital satisfaction of older couples leading to lower depression of husbands' and wives', and with higher depression of husbands' and wives' inducing lower marital satisfaction of the couples. Thus, this study suggested that longitudinal interplay between depression and marital satisfaction can lead to a vicious cycle. Based on these findings, the need to intervene at both the individual level and the couple level was discussed in order to reduce depression and improve marital satisfaction.

• Korean Journal of School Psychology
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• v.18 no.1
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• pp.71-97
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• 2021

The purpose of this study was to examine the mediating effects of the fear of compassion and the difficulties of emotional regulation on the relationship between attachment trauma and interpersonal problems. The participants in this study were 296 Korean university students. The participants completed self-report questionnaires that assessed their attachment trauma, fear of compassion, emotional regulation difficulties, and interpersonal problems. Those with high attachment trauma had significantly more interpersonal problems, fear of compassion from others, fear of self-compassion, and emotional regulation difficulties than those with low attachment trauma. Further, fear of compassion and difficulties in emotional regulation were shown to fully mediate and fully dual-mediate the relationship between attachment trauma and interpersonal problems. These findings suggest that attachment trauma affects the degree to which university students experience interpersonal problems and that fear of compassion and emotional regulation difficulties may be the mechanism underlying that relationship. This paper discusses several limitations of this study and areas for future research.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.1-13
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• 2022

This study aims to investigate the feasibility of the half-cell potential (HCP) measurements on the concrete surface for evaluation of corrosion rate (or corrosion levels) of reinforcing steel in concrete. A series of experimental study is performed to measure HCP (or corrosion potential, E_corr) and corrosion current density (i_corr) of reinforcing steel in concrete cube specimens, with a side length of 200 mm. Various corrosion levels in a range of 0% to 20% of the test specimens are accelerated by impressing current to the reinforcing steel in concrete immersed in 3.0 % NaCl solution. HCP is measured in accordance with ASTM C876-15, and corrosion current density is determined by using the Stern-Geary equation and measured polarization resistance measured by electrochemical impedance spectroscopy (EIS). As a result, a numerical formula that relates HCP and i_corr in the test specimen is established by a regression analysis of the measured data in this study. It is observed that HCP is linearly correlated with log(i_corr) with a R² greater than 0.87, which is less affected by the experimental variables such as concrete mixture proportion, diameter of reinforcing steel and the amount of applied current in this study. These results exhibit that HCP measurements could be effective for evaluation of corrosion rate (or corrosion levels) of reinforcing steel in concrete in the case of exposed to a certain consistent environment.

• Journal of Intelligence and Information Systems
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• v.28 no.4
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• pp.191-209
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• 2022

This paper is a review of studies that focus on the prediction of a won/dollar exchange rate before and after the covid 19 pandemic. The Korea economy has an unprecedent situation starting from 2021 up till 2022 where the won/dollar exchange rate has exceeded 1,400 KRW, a first time since the global financial crisis in 2008. The US Federal Reserve has raised the interest rate up to 2.5% (2022.7) called a 'Big Step' and the Korea central bank has also raised the interested rate up to 2.5% (2022.8) accordingly. In the unpredictable economic situation, the prediction of the won/dollar exchange rate has become more important than ever. The authors separated the period from 2015.Jan to 2022.Aug into three periods and built a best fitted ARIMA/ARDL prediction model using the period 1. Finally using the best the fitted prediction model, we predicted the won/dollar exchange rate for each period. The conclusions of the study were that during Period 3, when the usual relationship between exchange rates and economic factors appears, the ARDL model reflecting the variable relationship is a better predictive model, and in Period 2 of the transitional period, which deviates from the typical pattern of exchange rate and economic factors, the SARIMA model, which reflects only historical exchange rate trends, was validated as a model with a better predictive performance.

• Journal of Practical Engineering Education
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• v.14 no.1
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• pp.149-163
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• 2022

The rapid changes in the environment surrounding today's companies require continuous securing and retention of excellent human resources to maintain competitiveness. Therefore, research on work engagement (WE) and turnover intention (TI) was actively conducted as a representative factor necessary to secure the organizational competitive advantage and promote continuous growth. This is because the high performer has relatively high capabilities and high employability according to market demand, so securing and maintaining them is a very important issue from the perspective of corporate management. Research on the relationship between WE and TI have been conducted in various fields so far, but the results have been derived differently for each study. This means that there may be differences depending on the characteristics of the domestic context. However, studies that analyzed the relationship from a comprehensive and overall perspective are very rare, and the need for research is raised. Therefore, this study attempted to statistically analyze the relationship between variables and present research directions by synthesizing the results of existing studies. Through the analysis of previous studies, a meta-analysis was conducted on the effect of WE on TI within the organization in the domestic context to analyze the effect, and academic and practical implications were derived based on this.

• Journal of Korean Society of Forest Science
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• v.111 no.3
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• pp.345-356
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• 2022

Yokjido is a 15-km² inhabited island located at the tip of the southeastern coast of the Korean Peninsula. Its forest is mostly composed of substitutional vegetation. Our aim was to provide basic information necessary for the conservation and management of the forest vegetation in Yokjido. We classified the types of existing vegetation using methods of the Zurich-Montpellier school of phytosociology. The resulting vegetation map shows the dominant tree species in the top canopy-layer. A total of 8 vegetation types were identified, which were arranged into a vegetation unit hierarchy of 2 communities, 4 sub-communities, 6 variants, and 2 subvariants. Evaluations of each type showed large and small differences in floristic composition, which reflect anthropogenic influences, site conditions, succession stages, and the establishment period. Moreover, vegetation types differed significantly in terms of species diversity indices; in particular, overall species richness, species diversity, and species evenness tended to increase significantly as the elevation increased. The herbaceous plant species showed the highest positive (+) correlation to x. These results were consistent with those of McCain, who reported that species diversity increases in mountainous areas with relatively low elevations due to the mid-domain effect. The forest succession in Yokjido will potentially enter a mixed-forest stage and then proceed to become an all-evergreen broad-leaved forest.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.906-917
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• 2022

This study aimed to compare differences according to categories of fishery and marine environmental policies for the (estimated) amount of fishery waste generated by fishing, and to analyze the correlation between associated independent and dependent variables. The independent variables were divided into three dif erent sectors. The first sector included precautionary policies that observed eco-friendly fishing support program, institutional prevention activities, and physical barriers installation. The second sector with the current management policies included the relevant vessel operations, establishment of fishery order, fishery restructuring, and fishery ground clean-up. Thirdly, post-response policies comprised the litter purification from river to shoreline, the collection and removal of marine, sedimentary, and floating debris, purchasing salvaged debris generated while fishing, fishery waste disposal, and repairing damage caused by marine litter. The indicator used was the settlement amount by each program. The dependent variable was the estimated amount of fishery waste and the indicator was the sum of the loss of traps and gill nets and the loss of their appendages. According to the results of Kruskal-Wallis Test, the estimated amount of fishery waste was highest in the East Sea in terms of sea area and the highest in the Si(city) according to basic local municipality. The settlement amount related to the marine environment services was largest in the Gun(county). Further, there were significant differences between Gun(county) and the other regions(Si(city) and Gu(autonomous district)) with respect to most variables. The variables related to the estimated amount of fishery debris were the project purchasing salvaged debris generated while fishing and fishery waste disposal program in the post-response policies.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.3
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• pp.164-171
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• 2022

We studied the influence of Hanwoo (Korean native cattle) manure compost soil application on the growth and yield of maize (Zea mays L.). We compared the soil application of chemical fertilizer (CF), commercial manure (CM), Hanwoo manure (HM), and the mixed Hanwoo manure and chemical fertilizer (HM + CF). CF application showed faster tasseling and silking dates compared to the other treatments. During the early plant growth stage of maize, CF application resulted in taller plant height, However, during later growth stages (55 days after transplanting). HM (226.0 cm) and HM + CF (230.0 cm) treatment resulted in taller plant height compared to CF (216.2 cm). Post-harvest measurement results showed that, the ear length was longer in HM (22.13 cm) and HM + CF (22.70 cm) compared to others, while ear diameter, ear weight, and 100-grains weight showed no significant difference among CF, HM, and HM + CF groups. The use of HM resulted in delayed growth during the early stages of plant development compared to CF. However, crop productivity markers of ear weight and ear diameter showed no significant difference compared to CF. Thus, HM treatment was comparable to CF treatment in maize cultivation.

• Journal of Navigation and Port Research
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• v.46 no.4
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• pp.367-374
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• 2022

The purpose of this study was to propose a deep learning algorithm that applies to the fault diagnosis of fuel pumps and purifiers of autonomous ships. A deep learning algorithm reflecting the time dependence of the measured signal was configured, and the failure pattern was trained using the vibration signal, measured in the equipment's regular operation and failure state. Considering the sequential time-dependence of deterioration implied in the vibration signal, this study adopts Conv1D with sliding window computation for fault detection. The time dependence was also reflected, by transferring the measured signal from two-dimensional to three-dimensional. Additionally, the optimal values of the hyper-parameters of the Conv1D model were determined, using the grid search technique. Finally, the results show that the proposed data preprocessing method as well as the Conv1D model, can reflect the sequential dependency between the fault and its effect on the measured signal, and appropriately perform anomaly as well as failure detection, of the equipment chosen for application.

• Journal of Navigation and Port Research
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• v.46 no.4
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• pp.351-358
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• 2022

This study analyzed changes in the market concentration of Korean ocean-going shipping companies using shipping revenue based CR (Concentration Ratio), and HHI (Herfindahl - Hirschman Index) to examine the effects of the government's selection and concentration based the shipping reconstruction scheme. The results of this study showed that the market structure of the Korean shipping industry has changed from a competitive market to a rather concentrated market, as CR as well as HHI values have increased from 2019 to 2021. In particular, the market share of the deep-sea shipping lines has risen significantly compared to the intra-Asian short-sea shipping lines and the tramp carriers, implying that the Korean liner shipping market has become a monopoly, or highly concentrated oligopoly market. Compared to other shipping markets, the high rise in ocean freight rates (i.e. Asia-Europe America) was the leading cause of the increase in the revenues of the ocean-going shipping lines, and the increased fleet through preemptive government support has enabled them to achieve more revenues. As a result, it can be interpreted that the government's fleet expansion strategy has been more effective than expected, but it is too early to conclude if the market structure of the Korean ocean-going shipping companies has been strengthened.