• Journal of Korea Water Resources Association
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• v.51 no.10
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• pp.917-927
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• 2018

Seven heavy metal concentrations (As, Cd, Cr, Cu, Ni, Pb, Zn) were continuously analyzed for twenty rainfall events in 2017~2018 in an urban basin. The overall and dynamic correlations between runoff characteristics and heavy metal concentrations were examined. The peak metal concentration generally appeared in the initial runoff but found to be delayed when the rainfall intensity was low. The rainfall duration had no relationship with either heavy metal concentrations or their total mass. Dynamics of heavy metal mass (load), with the exception of Cu and Zn, showed strong correlation with the 30 minute rainfall intensity (0.60~0.88) and runoff volume (0.74~0.89). While event mean concentration (EMC) showed positive correlation (0.54~0.73) with antecedent dry days (ADD), no significant relationship was found between runoff volume and pollutant concentration. This implies that the pollutants built up on the surface during dry days are washed off even with low rainfall energy. The dynamics of heavy metal and TSS concentrations showed good correlation (0.68~0.87). This result shows that the metals are transported along with solid particles as adsorbate in surface runoff. Regular street sweeping will reduce significant amount of heavy metal loads in urban surface runoff.

• Korean Journal of Ecology and Environment
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• v.41 no.1
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• pp.43-53
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• 2008

This study was conducted to simulate storm hydrographs on a small forested watershed using TOPMODEL, which is a distributed hydrological model. The Myeongseong watershed, which is 58.3 ha in size, was selected to monitor rainfall and runoff data. The Monte Carlo simulation was also used to calibrate parameters of TOPMODEL. Six rainfall-runoff pairs collected at the watershed in the year 1997 were used for parameter calibration, and eight rainfall-runoff pairs collected during the period of $1998\sim1999$ were used for validation effort. The errors of runoff volume ranged from -2.74% to 1.81%, and an average value of model efficiency in terms of runoff volume was 0.92 for the calibration period. The average value of observed peak discharge was $0.324m^3\;s^{-1}$ for six rainfall-runoff pairs, while the prediction value was $0.295m^3\;s^{-1}$. The simulation errors of peak discharge varied according to rainfall characteristics and antecedent condition, within ranges of -27.65% to -1.13%. The model efficiency for the validation period was 0.92. For the validation period, observed peak discharges have an average value of $0.087m^3\;s^{-1}$ and average value of simulated peak discharge was $0.090m^3\;s^{-1}$. Observed and simulated values of time to peak for the calibration period were 18.3 hrs and 11.0 hrs, respectively, and 16.6 hrs and 13.5 hrs, respectively, for the validation period.

• Journal of the Korean GEO-environmental Society
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• v.17 no.5
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• pp.27-36
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• 2016

Low Impact Development (LID) techniques are eco-friendly storm water management process for water circulation restoration and non-point pollutant reduction. In this study, four LID techniques (Small constructed wetland, Infiltration trench box, Infiltration trench, Vegetated swale) were selected and installed as a real size at the real site. All facilities were evaluated as monitoring under the real environmental climate situation and an artificial rain with exceeding design rainfall. In various rainfall, runoff reduction efficiency and non-point pollutant removal efficiency are increased to the bigger Surface Area of LID (SA)/Catchment Area (CA) ratio and the bigger Storage Volume of LID (SV)/Catchment Area (CA) ratio. Runoff did not occur at all rainfall event (max. 17.2 mm) in infiltration trench and vegetated swale. But Small constructed wetland was more efficient at less than 10 mm, a efficiency of infiltration trench box was similar at different rainfall. Although different conditions (such as structural material of LID, rainfall flow rate, antecedent dry periods), LID techniques are good effects not only water circulation improvement but also water quality improvement.

• Journal of agriculture & life science
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• v.46 no.3
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• pp.129-141
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• 2012

The purpose of this study was to monitor the stream flow of rural streams for investigating the status of stream depletion located downstream of irrigation reservoir. Bonghyun and Hai reservoirs area, located in Hai-myeon, the city of Gosung, Gyeongsangnam Province, were selected for study watersheds and streams. Stream flow monitoring was conducted 7 times from March to September, 2011. Stream flow was measured for 8 stations downstream from two reservoirs. The stream depletion was found in most of the downstream of reservoirs for the non-irrigation period and even in the irrigation period when there were a lot of antecedent precipitation. The correlation analysis for water quality data indicated that the correlation between BOD and T-N was highest for the reservoirs. The correlation between BOD, T-N, and turbidity was high for Hai reservoir and Bonghyeon reservoir. Continuous monitoring for rural streams located in downstream of reservoirs are required to quantify the status of stream flow depletion and determine the amount of environmental flows.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.237-249
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• 2011

The purpose of this study was to monitor the streamflow of rural streams for investigating the status of stream depletion located downstream of irrigation reservoir. Bonghyun and Hi reservoirs area, located in Gyeongnam, Gosung-gun, Hi-myeon, were selected for study watersheds and streams. Streamflow monitoring were conducted 6 times during the paddy growing season of 2010 from May to October. Streamflow was measured for 18 stations downstream from two reservoirs with the interval of 300m to 500m, The amount of streamflow were highly dependent on the antecedent precipitation and irrigation amount. In most observation stations, streamflow was depleted when precipitation and irrigation were not provided. Pumping from stream for irrigation and water supply for factory and irrigation return flow were also factors on streamflow. Continuous monitoring for rural streams located in downstream of reservoirs are required to quantify the status of streamflow depletion and determine the amount of environmental flows.

• Journal of The Geomorphological Association of Korea
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• v.19 no.3
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• pp.71-82
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• 2012

This research was carried out to estimate annual erosion and retreat rates by using datum-point and to identify the characteristics and causes of seasonal variations of sea-cliff slope in Pado-ri, Taean-gun. In the result, the erosion and retreat rates of sea-cliff were increased from spring to summer. The rates were increased rapidly between August and October, caused by the effects of extreme weather events such as severe rainstorms and typhoons, etc. Since then, the erosion and retreat rates of sea-cliff were decreased gradually, but the rates were increased again in winter due to the storm surge and mechanical weathering resulting from the repeated freezing and thawing actions of bed rocks. The factors that affect erosion and retreat rates of sea-cliff include the number of days with antecedent participation and daily maximum wave height. In particular, it turned out that the erosion is accelerated by strong wave energy during storm surges and typhoons. The annual erosion and retreat rates of study area for the past two years(from May 2010 to May 2012) were approximately 44~60cm/yr in condition of differences in geomorphological and geological characteristics at each point. These erosion and retreat rates were found to be higher than results of previous researches. This is caused by coastal erosion forces strengthened by extreme weather events. The erosion and retreat process of sea-cliff in the study area is composed by denudation of onshore areas in addition to marine erosion(wave energy).

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.315-324
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• 2019

In this research, one of five Hofstede's cultural dimension, Long term orientation (LTO) was selected to examine its influence on individual's change oriented organizational citizenship behavior with emotional regulation mediating. East Asian countries and Korea especially received higher score on LTO cultural dimension, meaning it valued harmony, long term relations and saving for future. Also, in today's hyper competitive and evolving global climate, the ability to adapt quickly and also to be able to control one's emotion is highly valued individual competency. Previous research on Hofstede's cultural dimensions were conducted at mostly national or large group levels. However, in this study, Yoo's CVSCALE which allowed for individual level analysis on Hofstede's cultural dimensions were used to analyze multinational company's employees's long term orientations' influence on emotional regulation and change oriented organizational citizenship behavior. The survey conducted from 200 employees from major electronic company based in S city in Korea for two weeks period and the results indicated long term orientation positively influenced change oriented organizational citizenship behavior. Also emotional regulation mediated between long term orientation felt by individuals and change oriented organizational citizenship behavior. Such results validated previous studies that indicated emotional regulation as possible antecedents of individual proactive behaviors such as change organizational citizenship behavior and long term oriented view as another potential antecedent of change oriented organizational citizenship behavior in multinational corporation setting.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.159-168
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• 2019

This study draws on goal orientation theory and proposes the team learning goal orientation as an antecedent of team creativity. In addition, an Input-Process-Output (IPO) model was adopted, in which the team reflexivity, team efficacy, and positive group affective tone (PGAT) are linking mechanisms in the relationship between team learning goal orientation and team creativity. Using 57 teams from three lectures of the college, hierarchical regression analysis was conducted at the team level. The results showed that the team learning goal orientation had positive associations with team creativity, team reflexivity, and team efficacy. In addition, team reflexivity and team efficacy positively predicted the team creativity. Furthermore, the relationship between team learning goal orientation and team creativity was mediated by the team reflexivity and team efficacy. In contrast to predictions, PGAT did not show significant relations with both team learning goal orientation and team creativity. In conclusion, this study integrated the team-learning goal orientation and team creativity literature and contributes to the understanding of team reflexivity as a cognitive process and team efficacy as a motivational process between the team property and team creativity. These results have practical implications for managing teams.

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.581-592
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• 2019

This study investigates the factors that stimulate or suppress the use of food delivery applications. As potential antecedent factors, the present research examined the review diagnosticity, descriptive norms, and multidimensional risk perception. Based on this, users' data were collected from major metropolitan cities where the food delivery application business is most active. The results of structural equation modeling confirmed that users' approach to food delivery apps becomes more favorable when the review diagnosticity and descriptive norms were improved and when the perceived multidimensional risk expected to be associated with app use is mitigated. Additionally, we found that the positive influence of these attitudes on the actual intention to accept delivery applications became weaker at higher levels of perceived risk. These empirical results may contribute to the formation of strategic and systematic guidelines for promoting the expansion of the recently emerging O2O service platform across diverse sectors. Namely, the significance of this study lies in that it has raised awareness regarding the strategic considerations that such new O2O service providers should take into account for their market positions, in addition to discovering factors that could aid the prompt expansion of the applications' user base.

• Journal of Convergence for Information Technology
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• v.11 no.12
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• pp.49-58
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• 2021

This study examined the effects of antecedent variables on life satisfaction of elderly people who live alone and who live with others by comparing the levels of depression, self-esteem, and life satisfaction. Using the 15th data of the Korean Welfare Panel held in 2020, independent sample t-test and hierarchical regression analysis were conducted. Elderly people who live alone had a high sense of depression, low self-esteem, and low life satisfaction. For both of them, the older the age and the higher the income level, the higher the life satisfaction. The regression model, which added depression and self-esteem, had a significant effect on both of them, but the effect of self-esteem was higher (𝛽=.40, .41) than that of depression (𝛽=-.28, -.29). The effects of depression and self-esteem on life satisfaction were higher in elderly people who live alone (R²=.409) than in elderly people who live with others (R²=.398). Based on the research results, this study suggested appropriate policies and practice directions to enhance self-esteem and improve life satisfaction of elderly people who live alone.