• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.5
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• pp.281-294
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• 2015

In order to quantitatively estimate the nonlinear destructive interaction of wave load with wind load, which is very vital for the optimal design of offshore wind energy converter, we carried out a hydraulic model test and wind tunnel test. As a substructure of offshore wind energy converter, we would deploy the monopile, which is popular due to its easiness in construction. Based on the simulation using Monte Carlo simulation using Kaimal spectrum and cross spectrum, the instantaneous maximum wind velocity is adjusted to 10 m/s. And, considering the wave conditions of the Western Sea where a pilot wind farm is planned to be constructed, $H_s=0.1m$, 0.15 m, 0.2 m is carefully chosen. It turns out that the nonlinear destructive interaction between the wind and wave loads acting on the offshore wind energy converter is more clearly visible at rough seas rather than at mild seas, which strongly support our deduction that a Large eddy, a swirling vortex developed near the bumpy water surface in the opposite direction of the wind, is the driving mechanism underlying nonlinear destructive interaction between the wind and wave loads.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.9
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• pp.666-674
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• 2013

Physical disturbance, which induces a lack of flow rate, frequently occurs in freshwater ecosystem. Due to this, it is required to provide a new fish shelter to resolve. We installed a pilot scale test-bed to scrutinize the relationship between water level and the influence of fish shelter. The proposed ADP (artificial deep pool) is a fish shelter which composed of concrete materials. From the monitoring results in test-bed, it was observed that the population of fish was the highest at the 0.5 m in depth from the water level of experimental pond. But it was more appropriate for shallow water level (<0.3 m) to conserve the total number of fish by increasing the number per unit area despite of lower inner temperature and DO than outer environment. Therefore, inner of ADP was more efficient lentic system for fish to live due to higher WCS, OS, SS, and TS. In addition, there was a relative abundance of WCS fish species such as Acheilognathus koreensis (A. koreensis), Carassius carassius (C. carassius). Considered these results, it is suggested that ADP is appropriate to use for fish shelter and habitat for the fishes in lentic ecosystem.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.3
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• pp.201-209
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• 2004

Important operation parameters and performance of a high temperature ceramic candle filter system were evaluated through a series of demonstration tests at a pilot-scale vitrification plant. At the initial period of each test, due to the growth of dust cake on the surface of ceramic candles, the pressure drop across the filter media increased sharply. After that it became stable to a certain range and varied continuously proportion to the face velocity of off-gas. On the contrary, at the initial period of each test, the permeability of filter element decreased rapidly and then it became stable. Back flushing of the filter system was effective under the back flushing air pressure range of 3∼5 bar. Based on the dust concentrations measured by iso-kinetic dust sampling at the inlet and outlet point of HTF, the dust collection efficiency of HTF evaluated. The result met the designed performance value of 99.9%. During the demonstration tests including a hundred hour long test, no specific failure or problem affecting the performance of HTF system were observed.

• Journal of the Korean Geosynthetics Society
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• v.1 no.1
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• pp.13-21
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• 2002

Geotextile tubes hydraulically or mechanically filled with dredged materials have been applied in hydraulic and coastal engineering in recent years(detached breakwater, groins and jetty). The geotextile tubes are made of sewn geosynthetics sheets. If the sandy soil is use to fill material, these inlets should be spaced closely to assure uniform filling of the tubes because sandy soil and geosynthetic is very pervious. However, the clayey soil or contaminated slurry is used, the inlets can be located relatively long distance. The fine clayey particles tend to rapidly blind the fabric slowing down water escape through the geotextile. This paper presents a field test result of a geotextile tube in the land reclamation project for the Songdo New City construction site. The dredged silty clay was dredged by the dredging ship and hydraulically pumped into the geotextile tube. The height of geotextile tube was measured at every filling stage and also measured width and diameter of geotextile tube with the elapsed time. Based on the test results, if the clayey filling material is used, the pumping step must be divided 3~4 stages for drainage and sediment. After complete drainage, the height of the geotextile tube reduces by approximately 50%.

• Journal of Korea Port Economic Association
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• v.25 no.3
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• pp.183-206
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• 2009

The purpose of this study is to suggest the new strategies for strengthening the competi tiveness of Incheon port. To measure the calling factors and satisfaction of ports, this study developed a list of 24 items using a seven-point Likert scale through the previous literature reviews, pilot test and emerging factors. Factor analysis, regression analysis, one sample T-test, IPA and SPSS were conducted to verify the determinants choosing ports and customer satisfaction. The result of an empirical study revealed that the cargo volume and information system, etc. in Incheon port was evaluated as satisfied factors and berth availability and port charge, etc. as dissatisfied factors. Based on the outcomes of this study, to strengthen the competitiveness of Incheon port, several strategies were advised such as the inducement of North American and European cargo, port infrastructure, dedicated terminal and GTO inducement, hinterland construction, logistics companies inducement and cooperation with neighboring ports.

• Journal of Korean Academy of Nursing
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• v.26 no.4
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• pp.808-819
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• 1996

The purpose of this study was to examine the stressors and coping strategies of school -age children and to explore the relationship between stressful life events and health symptoms and the effects of coping and trait anxiety which is theoretically considered to mediate the relationship between stress and health symptom. The study subjects consisted of 639 elementary school children in the fourth to sixth grade living in Seoul. Of the 639 subjects, 348 were boys and 291 were girls. The mean age was 11.35 (SD=.86). The Feel Bad Scale(FBS), Schoolager's Coping Strategy Inventory(SCSI), Spielberger's Trait Anxiety Scale for Children(STAIC), and Health Symptom Questionnaire (HSQ) were adapted for this study. A pilot study was undertaken to ascertain the reliability and validity of the instruments. The Cronbach alphas of FBS, SCSI, STAIC and HSQ were from .81 to .92. The Researcher and a research assistant visited the school and data were collected in the class using the questionnaire method after an explanation of the purpose and procedures was given to the children. Data collection was done during the period between Nov.25 to Dec.19, 1995. Using the SAS statistical program, percentages, t-test, ANOVA, correlation analysis, and multiple regression were used for data analysis. The result are as follows : 1. The mean score for the FBS was 204.79(range : 48-472) and there was a significant difference according to grade. The most severe stressors perceived by children were parental divorce and death or illness of family members. The most frequently experienced stressful life events were conflict with siblings and being home alone. 2. The mean score for the SCSI was 57.36(range : 9-118) and there was a significant difference according to grade. The most frequently used, and perceived as helpful, coping strategies were distraction and cognitive activities. 3. The mean score for the HSQ were 20.7(range : 0-81) and there were significant differences according to grade and sex. The percentage of the children answering that they perceived their health state as not good was 3.9%. 4. The mean score for the STAIC was 33.76 and there were significant differences according to grade and sex. 5. There was a significant relationship between stressful life events and health symptoms ( r=.53, p<.01). Also, Stressful life events were postively related with coping strategies(r=.39, p<.01). Trait anxiety was highly correlated with health symptoms(r=.72, p<.01). 6. To examine the multivariate effects of the variables to health symptoms, multiple regression was performed. Stressful life events, coping, trait anxiety, and health concerns were identified as significant variables. Explanation of the health symptoms by these variables was 56.78%. The study revealed that stressful life events correlated with health symptoms in school-age children and coping and trait anxiety had mediating effects on this relationship. The implication for nursing is that there is a need to develop supportive interventions for high risk population to decrease health problems due to stress. Also, it is recommended that a study be conducted to explore protective factors for the prevention of health problems in children.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.556-567
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• 2016

The aim of this study is to make an education satisfaction assessment tool in university. For this, the related study, researchers meeting were conducted and 20 university students were involved in checking items, and then inventory items were completed. The pilot test was conducted at university in Choongnam Province for EFA(Exploratory Factor Analysis by using outcome data. From them, 4 sub-areas and 12 factors were consisted. The 4 sub-areas are education method, education contents, education environment, and education outputs. The education method is composed of appropriateness and fairness of classroom activities, the education contents are composed of systemization of education contents, the diversity and quality of education contents, and the effectiveness of education contents. The education environment is configured as educational facilities and environment, educational supporting service and administrative services. For content validity, items which adapted over 0.90 S-CVI : Standard Content Validity Index. To 48 inventory items obtained proper contents validity and reliability, measurement of suitability of verification was conducted. Cronbach's ${\alpha}$ of reliability test has emerged as highly 0.987. In CFA(Complimentary Factor Analysis), CFGFI, CFL, TLI, RMSEA, NFI indexes show a good value, therefore, this assessment tool for educational satisfaction in university is suitable for measuring tool.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.1 s.60
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• pp.29-32
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• 2007

We investigated new ingredients with real efficacy in both in vitro and in vivo all together. Especially we focused on the real improving effort in the clinical experiments. Because most products containing effective materials evaluated in vitro failed to show a real improving effect in the human with acne. We evaluated the well-known ingredients in a small scale clinical experiment with half-finished goods containing each ingredient. Among these products, product formulating SeleMix AN composed with germinating soy bean and magnolias bark extract remarkably improved acne and acne scar. Moreover skin redness caused by severe acne was improved. There was statistical significance between placebo and sample. Two hundred volunteers participated in our pilot study with written informed consent. After then we performed in vitro efficacy test this ingredient. SeleMix AN inhibited the growth of propionibacterium acnes at a concentration of 0.0125% and suppressed histamine release by 16.9%. Moreover human fibroblast cell activity was increased by 57% compared to control. Lastly, we performed a clinical study. Consisting of groups of 23 volunteers. Although the period of the test was in summer accelerating sebum secretion and recurring a high tate of acne, inflammation lesions were especially improved after applying product containing SeleMix AN for 4 weeks.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.126-132
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• 2014

A pilot-scale electrokinetic (EK) separation field test ($2{\times}3{\times}0.2m^3$, $W{\times}L{\times}D$) was performed in a greenhouse to remove salts from saline soil. Initially, the greenhouse soil had high electrical conductivity (EC), about 9 dS/m, and contained mainly $Ca^{2+}$, $Cl^-$ and $SO_4^{2-}$ ions. After 2 weeks of EK treatment, the soil EC was reduced to 52% compared with its initial value. The EC reduction was mostly achieved within the first week (47%) due to removal of $Na^+$ and $Cl^-$ ions, but ions with a high adsorption capacity such as $Ca^{2+}$ and $SO_4^{2-}$ ions were difficult to be removed. During the EK test, the soil temperature increased and it reached around $50^{\circ}C$ at some regions. For in situ application to soils in cultivation, the current should be controlled to limit increases in temperature, especially near the cathodes. In conclusion, the in situ EK technique is feasible for the restoration of saline greenhouse soils in or no cultivation and an appropriate strategy is necessary for more effective remediation.

• Economic and Environmental Geology
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• v.45 no.3
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• pp.255-264
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• 2012

The stabilization using limestone ($CaCO_3$) and steel making slag as the immobilization amendments for Cu and Pb contaminated farmland soils was investigated by batch tests, continuous column experiments and the pilot scale feasibility study with 4 testing grounds at the contaminated site. From the results of batch experiment, the amendment with the mixture of 3% of limestone and 2% of steel making slag reduced more than 85% of Cu and Pb compared with the soil without amendment. The acryl column (1 m in length and 15 cm in diameter) equipped with valves, tubes and a sprinkler was used for the continuous column experiments. Without the amendment, the Pb concentration of the leachate from the column maintained higher than 0.1 mg/L (groundwater tolerance limit). However, the amendment with 3% limestone and 2% steel making slag reduced more than 60% of Pb leaching concentration within 1 year and the Pb concentration of leachate maintained below 0.04 mg/L. For the testing ground without the amendment, the Pb and Cu concentrations of soil water after 60 days incubation were 0.38 mg/L and 0.69 mg/l, respectively, suggesting that the continuous leaching of Cu and Pb may occur from the site. For the testing ground amended with mixture of 3% of limestone + 2% of steel making slag, no water soluble Pb and Cu were detected after 20 days incubation. For all testing grounds, the ratio of Pb and Cu transfer to plant showed as following: root > leaves(including stem) > rice grain. The amendment with limestone and steel making slag reduced more than 75% Pb and Cu transfer to plant comparing with no amendment. The results of this study showed that the amendment with mixture of limestone and steel making slag decreases not only the leaching of heavy metals but also the plant transfer from the soil.