• Journal of Korean Society on Water Environment
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• v.18 no.2
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• pp.151-157
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• 2002

Landfill leachate is one of highly contaminated and heterogeneous wastewater. The leachate from initial landfill can be treated by anaerobic process because it contains biodegradable matters, particularly, volatile fatty acids (VFAs). However, the anaerobic treatment of leachate is generally required longer hydraulic retention time (HRT) than aerobic process and another treatment process to satisfy effluent concentration. Therefore the modification of conventional anaerobic treatment is needed. Two phase anaerobic membrane process (TPAMP) is an integrated membrane process to be able to separate anaerobic metabolism into two phase which are acidogenesis and methanogenesis for improvement of anaerobic treatment efficiency. In this study, the efficiency of TPAMP and conventional anaerobic treatment were compared in terms of HRT, effluent SCOD, VFAs Membrane used in TPAMP was the UF of capillary type with the surface area of $0.048m^2$. The average effluent SCOD of conventional anaerobic treatment was 1352 mg/L and the removal was 96 % at HRT 60 days, while in TPAMP, 927 mg/L and 98% at HRT 30 days.

• The Journal of Korean Society for School & Community Health Education
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• v.15 no.3
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• pp.55-65
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• 2014

Objectives: This study aims to develop a decent sallimyok program and provide basic data which are helpful in improving psychological wellbeing for adults who are exposed to stress and fatigue. Methods: Middle-aged women living in Cheongju, Chungbuk were divided into experimental and control groups (10 people each) through convenience sampling, and a questionnaire survey on psychological wellbeing was distributed to them and collected. For data analysis, IBM/SPSS 20.0 was used. In terms of statistical analysis, a reliability test (Cronbach's ${\alpha}$) was conducted. To test research questions 1 and 2, independent t-test and paired sample t-test were carried out. Results: First, a sallimyok program features meditation (floor-sitting, slow walk), forest therapy, stretching exercise, wrapping-up and sharing feelings. Second, it was confirmed that a sallimyok program has a positive effect on the improvement of psychological wellbeing and the depression for women. Conclusions: The sallimyok program improved participants' psychological wellbeing, which means that it could reduce their anxiety and stress.

• Journal of the Korean Society of Safety
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• v.37 no.3
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• pp.34-44
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• 2022

This study analyzed the smart construction safety cost included in safety management plans that are approved before construction. Specifically, it refers to the cost incurred in constructing and operating a safety management system using wireless communication and facilities. Based on the obtained statistical results, an activation policy for the inclusion of the smart construction safety cost in building safety management plans was proposed. The smart construction safety cost must be included in the safety management cost; notably, this is mandated by the Construction Technology Promotion Act. However, there are some problems with the inclusion of smart construction safety costs. To analyze the problems encountered when calculating the smart construction safety cost and including it in safety management plans, in this study, statistical analysis was performed using the data of 1,334 safety management plans received at the Construction Safety Management Integrated Information (CSI) from June to August 2021. The results show that only 50.7% of the safety management plans included the smart construction safety cost although the current law mandates 100% inclusion of these costs. Thus, it is apparent that the smart construction safety costs are only included in a low proportion of sites. In addition, the calculated smart construction safety costs were shown to have a small correlation with the construction cost; moreover, they appeared to be distributed at a constant cost level. In this context, it is believed that perfunctory cost calculations were performed at most sites since the effect of the construction cost on the smart construction safety cost was negligible. Therefore, it is necessary to improve the inclusion of smart construction safety costs by strengthening the authorization process of the approval institute of safety management plans. In addition, institutional support, such as guidelines that promote the calculation and inclusion of appropriate smart construction safety costs according to the characteristics of sites, are needed.

• Journal of the Korean Society for Library and Information Science
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• v.57 no.1
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• pp.183-211
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• 2023

As a private school and a library in the Enlightenment Period of Korea, Woo-Hyun Seoru(友弦書樓) was established between 1904 - March 1905 by Lee, Dong Jin who had a will and provided a economic support for it and his son Lee, Il Woo had founded and operated it and it seemed to be closed in 1911. By this time, Woo-Hyun Seoru has been underestimated or ignored in the history of libraries in Korea. This study tried to investigate 8 aspects of Woo-Hyun Seoru as a modern library including the subject and purpose of establishment, the date of establishment, the location and buildings, the collection development and the acquisition methods, the user group and the important users, the library activities, the process of closure, and the moving path of the collections after the closure of Woo-Hyun Seoru. To do this, the articles of newspaper, periodicals, and academic journals, the relating documents and Sung Nam Se Go(城南世稿) written by Dong Jin Lee, Il Woo Lee and their descendants and colleagues were analyzed.

• Ocean and Polar Research
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• v.32 no.4
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• pp.337-350
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• 2010

This study conducted sedimentological and geophysical surveys for 3 years (2006-2008) in southern Gyeonggi Bay, Korea to elucidate temporal changes in subaqueous dune morphology on a sand ridge trending northeast to southwest that has been excavated by marine sand mining. The sand ridge (~20 m in height, ~2 km in width and 3~4 km in length) has a steep slope on the NW side and a gentle slope on the SE side, creating an asymmetric profile. Large (10~100 m in length) and very large (>100 m in length) dunes occurring on the SE side of the ridge show a northeastward asymmetrical shape, whereas dunes on the NW side destroyed by marine sand mining display a southwestward asymmetry. The comparison between Flemming (1988)'s correlation and the height-length correlation of this study indicates that tidal current and availability of sand sediment are major controlling factors to the development and maintenance of dunes. Depth and sedimentary characteristics (grain size) are not likely to be major controlling factors, but indirectly influence dune growth by hydrological and sedimentary processes. The length and the height of dunes decrease toward the southeastern trough away from the crest of the ridge. These features result from the decrease of tidal current and sediment availability. The length and the height of dunes on the southeast side decrease gradually over time. This is a result of the interaction between tidal current and the decrease in sediment availability due to sediment extraction by marine sand mining. Marine sand mining has destroyed the dunes directly, causing irregular shapes of shorter length and lower height. The coarse fraction of suspended sediments is transported and deposited very close to the sand pit. By contrast, relatively fine sediments are transported by the tidal current and deposited over a wide range by the settling-lag effect, resulting in a decrease of sediment grain size in the area where suspended sediments are deposited. In addition, marine sand mining, decreases the height of dunes. Therefore, morphological and sedimentological characteristics of dunes around the sand pits will be significantly changed by future sand mining activities.

• Geophysics and Geophysical Exploration
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• v.11 no.3
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• pp.197-203
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• 2008

A shallow high-resolution seismic reflection survey was carried out at the Mineopo tidal flat on the western coast of Korea. The purpose of the survey was to investigate shallow sedimentary structure of the tidal flat associated with the recent sea level change. A total of 795 shots were generated at 1 m interval from a 5-kg hammer source and recorded on 48 channels of 100 Hz geophones along two mutually perpendicular profiles. The water-saturated ground condition resulted in suppressed ground rolls by significantly decreasing rigidity. In addition, seismic velocities over 1500 m/s provided easy segregation of reflected arrivals from lower velocity noise. As a consequence, seismic sections from the study area show significantly higher resolution and signal to noise ratio than conventional land seismic sections. The tidal flat consists of 5 sedimentary sequences above acoustic basement. The seismic sections reveal the continuous structure of the tidal flat formed in association with sea level rise during the Holocene.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.2
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• pp.59-66
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• 2005

Accuracy of current measurement in fiber optic current sensor(FOCS), especially, unidirectional polarimetric fiber optic current sensor(PFOCS) is affected by the environment perturbations such as acoustic vibrations changes to the sensing fiber, and intrinsic perturbations such as the bending fiber that the sensing fiber wound around a current carrying wire. The perturbations affect the birefringence properties of sensing fiber in sensor head and cause false current readings. Thus, using compensation technique, reciprocal PFOCS, for unidirectional PFOCS the perturbations are suppressed. In this paper, we carried out the numerical analysis of performance in reciprocal PFOCS including the degree of polarization error, and false current of environmental and intrinsic perturbations on the sensing fiber. Also, we compared the effect of mirror with the faraday rotation mirror(FRM) in reciprocal PFOCS configuration. And the different optical source's wavelengths, 633nm and 1300nm is used. In the results, at 633nm, using mirror and FRM, the degree of polarization error is calculated to $2.3\%$ and $0.0196\%$, respectively. At $1300{\cal}nm$ using mirror and FRM the degree of polarization error is calculated to $9.97\%$ and $0.0196\%$, respectively. Also, compared with false current, the results is calculated to $9.82{\times}10^{-9}A$ and $1.4{\times}10^{-17}A$, respectively, and show that the reciprocal PFOCS is more robust configuration than unidiretionnal PFOCS for environmental and intrinsic perturbations.

• Archives of design research
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• v.20 no.1 s.69
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• pp.79-88
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• 2007

A company's plan to reform its products' image cannot obtain expected results unless a color plan is included in the reformation plan. A color plan is essential since color conveys to customers much information on function, shape, and material quality of the product. In other words, color is the essential dimension or criteria that customers use when evaluating the quality of goods. Despite the importance of a color plan, companies in Korea are still behind in researching and receiving 'color information' compared to those in more advanced countries. Recognizing the importance of products color, many international companies constantly make their efforts to predict trendy colors and preferred styles of customers before they develop products. It is suggested that domestic companies invest more in color infrastructure to be more successful in making products which can catch the customers' eyes and emotion. Different life styles by age, income level, and gender would be only a few of many factors to be investigated to build color plans for a product. In this study, it is attempted to see the color tendency of young generation by gender, and also to analyze empirically the influence of product's color on its image and customers' behavior. The results are analyzed with frequency analysis, cross tabulation analysis, T-test, one-way ANOVA using SPSS Win 12. The results of this study show that color preference, product image and product attitude are influenced by product's color, and color is an important factor for forming additional emotional value together with the product's original functional value. Judging from the findings, it is recommended that a company undertake careful research before developing a product to find out how customers respond differently to products in different colors especially when the product belongs to the product category where color is considered to be a determinant factor in terms of choosing a brand.

• Korean Journal of Ecology and Environment
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• v.38 no.4 s.114
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• pp.445-453
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• 2005

Relative importance between bottom-up and top-down controls on phytoplankton dynamics was investigated in the Juam Reservoir, Chonnam based on the results from statistical analyses including regression and artificial neural network (ANN) modeling. Effects of nutrients on size-structured phytoplankton dynamics were explored by simple linear regression analysis and relative importance between bottom-up and top-down controls was estimated based on results from the artificial neural network analyses. Although there is a limitation in determining direct grazing effects since chlorophyll a : pheopigments ratios, indirect index for grazing activity rather than grazing rates or herbivores biomass were used, the results from regression analysis showed that nutrients especially orthophosphates were positively correlated with the phytoplankton biomass and chlorophyll a : pheopigments ratios were also positively correlated with the phytoplankton biomass at lower coefficient of determination ($r^2$) compared to orthophosphates. The simulation results from ANN suggested that the bottom-up mechanisms including water temperature and availability of nutrients, especially orthophosphates were more important than top-down mechanisms such as grazing in the phytoplankton dynamics.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.2
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• pp.130-137
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• 2012

The underwater glider using conception of Lagrangian method, is a new observation platform to understand the properties of the ocean vertically. In 2011 March, KORDI made a first successful autonomous trip from Hupo to west coast of Uleungdo piloting Littoral Glider of Alaska Native Technology LLC. The journey considered many environmental variables and route vigilantly selected, the glider covered 177 km horizontally and took approximately 6 days (153 hours). Despite the existence of 1 kt eddy current, Sound velocity sampling was conducted from 5 meters and reaching maximum of 200 meters depth at each dive. It successfully collected sound velocity and temperature profile at every 5 seconds totaling up to 1408 profiles using SVT&P sensor. During the flight it was also a mission to check the diverse modes of the glider i.e. spiral, waypoints, heading, drift and hover could function without a defect in a given situation. These modes were thoroughly monitored and it could be considered that the glider handled it well during the flight. As a result of this test flight, it was evident that the given underwater glider could operate under 2kt current environment with users defined heading and depth, also with the payload up to 5 kg without changing internal buoyancy.