• Journal of Navigation and Port Research
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• v.29 no.6 s.102
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• pp.573-581
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• 2005

The outbound containers in a container terminal are classified into a few groups by their weights and stacked separately in a yard for easy and efficient handling. In order to maintain the balance of a ship during loading, containers of heavier weight groups should be fetched out of a yard and loaded onto the ship before those of lighter weight groups. However, the weight information used to determine the weight group is usually imprecise. Therefore stacks will actually be filled with mixture of different weight groups and rehandlings are unavoidable during loading operation. This paper presents a method for estimating the number of rehandlings caused by imprecise information and a scheme for generating a simple but efficient slot assignment rule. Experiments have shown that a rule generated by the proposed method can reduce the number of rehandlings by about $20\%$ compared to the traditional slot assignment method which stacks only the containers of the same weight group in a single stack.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.12
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• pp.2187-2195
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• 2000

A water treatment system using membrane separation technology can provide stable effluent quality and its maintenance is relatively easy comparing to the conventional water treatment system. In addition, the membrane filtration system is very compact such that it can replace existing water treatment processes of coagulation/sedimentation/filtration by only one process. However, a major problem associated with membrane filtration is flux decline with operating time due to concentration polarization and fouling, so a systematic study on evaluation of long-term filtration performance is necessary. A membrane filtration system using tubular type ultrafiltration membranes with MWCO of 30.000 Da was constructed for this study and it had been operated in a feed-and-discontinuous bleed mode. Flux was stabilized after operation of 1.500 hours and maintaining above 25 LMH until 4.000 hours. Contaminants causing SS and turbidity were almost completely removed while the $UV_{260}$ and DOC removals were 55% and 49%, respectively. A simple mass balance equation was developed to predict maximum concentrations of SS, turbidity, $UV_{260}$ and DOC in a operation cycle. For SS and turbidity the measured max, concentrations in each cycle agree well with the predicted values while the measured max, concentrations of $UV_{260}$ and DOC were 59% and 37% of the predicted values, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.10
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• pp.1777-1787
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• 2000

The purpose of this study was to select an effective and economical alkali source for sulfur-utilizing autotrophic denitrification. Tests on acid neutralization and denitrification at various alkali/sulfur mixing ratios were performed for charcoal, briquette ashes, sea shell, and limestone. The results of the experiments showed that sea shell was the most effective alkali source because it could provide more surface area than limestone, and the optimal alkali/sulfur mixing ratio was 1/1(V/V). In a sulfur/sea shell packed bed reactor, the denitrification efficiency was above 90% up to a loading rate of 116 g $NO_3{^-}-N/m^3-day$. but the denitrification efficiency deteriorated to 48% at the loading rate of 145 g $NO_3{^-}-N/m^3-day$. The average $SO_4{^{2-}}$ generation per g of $NO_3{^-}-N$ removed was 7.02 g, which is lower than the theoretical value of 7.54 g. Denitrification and sulfate generation appeared to be a first-order and a zero-order reaction with a reaction rate constant of 0.146 /hr and -53.1 mg/L-hr, respectively. According to nitrogen mass balance, 71~109%, with an average of 90%, of the removed nitrogen was recovered as $N_2$ gas.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.1
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• pp.69-78
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• 2008

An integration study of watershed model(HSPF, Hydological Simulation program-Fortran) and reservoir water quality model (CE-QUAL-W2) was performed for the evaluation of turbid water management in Yongdam reservoir. The watershed model was calibrated and analyzed for flow and suspended solid concentration variation during rainy period, their results were inputted for reservoir water quality model as time-variable water temperature and turbidity. Results of the watershed model showed a good agreement with the field measurements of flow and suspended solid. Also, results of the reservoir water quality model showed a good agreement with the filed measurements of water balance, water temperature and turbidity using linkage of the watershed model results. Integration of watershed and reservoir model is an important in turbid water management because flow and turbidity in stream and high turbidity layer in reservoir could be predicted and analyzed. In this study, the integration of HSPF and CE-QUAL-W2 was applied for the turbid water management in Yongdam reservoir, where it is evaluated to be appliable and important.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.3
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• pp.227-237
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• 2012

This paper analyzes the current status, characteristics, and problems of coastal reclamation in Korea and suggests effective management approaches. Reclamation is concentrated from the West Sea to the South Sea. In the 1980s and 1990s, most projects were intended for agricultural use, whereas in recent years reclamation for industrial and harbour sites(e.g., ship-building) have been increasing. The continuous onslaught of reclamation and development projects threatens the coastal environment, especially tidal flats and fishing areas, and fishery production has been reduced in some areas. The largest tidal flats have been used for dumping sites of dredged coastal sediments, urban development projects, and industrial complex composition. Thus, it is necessary to assess current policy using top-down approaches after establishing appropriate directions and standards for coastal management. Both short-term development profits and long-term conservation should be considered when attempting to balance development and conservation. In addition, improvements of marine environmental impact assessment and in the legal system are necessary.

• Journal of Nutrition and Health
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• v.14 no.4
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• pp.200-208
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• 1981

A survey was conducted from January 23 to 31 and February 14 to 18, 1981, in Whaseounggun, Kyunggj-do, to investigate the dietary and nutritionary status, and prevalence of parasitic infection of the fertile women, in an attempt to provide an integrative perspective on the rural family health programmes. The results are summarised as follows; The total number of fertile women, randomly selected, was 197 ; 21 women were in the latter half of pregnancy; 38 women, lactating, the remaning, non-pregnant. Average age of the subjects was 31.4 years; average number of children, 2.7; average number of abortion, 0.9; average family number in home, 5.5. The families had a mean income of \ 2,470,000 per fear. The majority, 83.8% of the families, were engaged in farming. 61.4% of the subjects had completed schooling 6 years or less. The mean energy intake of the lactating women was 73.4% of the recommended allowance, while that of non-pregnant and pregnant women reached 86.9 to 88.6% of the recommendation. In the average diet of the subjects, carbohydrates contribute 74.6 to 81.7% of the total energy intake; protein 11.3 to 11.9%; fat 7.0 to 13.9%. Protein intake of non-pregnant, pregnant, and lactating women met 72.6%, 60.8%, and 65.2% of allowance, respectively; and those proteins were mainly derived from vegetable sources. The subjects ingested less than one-half of the allowances for iron, calcium, vitamin A, and riboflabin ; in contrast, thiamin and ascorbic acid levels were adequate or fairly acceptable. There were significant correlations of meal balance and food diversity scores to the mean intake levels of protein, calcium, iron, vitamin A, thiamin, and riboflavin. Only 10% of the pregnant women and 11.4% of non-pregnant and lactating women reached the acceptable level of hemoglobin. Positive prevalence of parasitic infection was found among about one-third of the subjects, 30.3% of women. Hematologic findings had no significant correlation to parasitic infection.

• The Journal of the Korea Contents Association
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• v.20 no.9
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• pp.296-307
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• 2020

Compared to the quantitative increase in women's workforce, women's status in the organization remains poor. When it needs diverse perspectives and flexibility cope with the environment, it is an urgent challenge for companies to manage women in organizations. In this study, it is explored the internal factors of the organization that allow women managers to be more immersed in the organization. While previous researches have focused mainly on employment equality policies, this study expands the scope of existing research by considering the organization's internal support factors, such as mentoring, education and training, and organizational atmosphere. The female manager panel data showed that mentoring, education and training, and organizational climate all increase the leading influence of female. This leading influence affects organizational commitment and mediated between organizational internal factors and organizational commitment. In other words, it has been found that it is important for female managers to take the initiative in their position as well as the internal support of companies for female managers to immerse themselves in the organization. This study could contribute to solving the dilemma of the use of women's workforce by companies that fail to recover all investment costs such as recruitment, education, training, and compensation of excellent women's workforce.

• Korean Journal of Oriental Medicine
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• v.6 no.1
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• pp.123-132
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• 2000

Bone is continuously remodeled during adult life with the resorption of old bone by osteoclasts and its subsequent replacement by osteoblast. Bone homeostasis is maintained by a balance between activities of osteoblasts and osteoclasts, but an imbalance between resorption and formation results in bone diseases including osteoporosis. Osteoblasts line up on the bone surface, especially regions of new bone formation, lay down bone matrix (osteoid) in orderly lamellae and induce its mineralization. Thus, the increased activity of osteoblasts is helpful to treat and prevent osteoporosis. In this study, we examined whether 80% EtOH extract of yukmijiwhang-whan is capable of affecting osteoblast proliferation using human osteoblast-like cell line, MG-63 and Saos-2. In an in vivo experiment, extract of yukmijiwhang-whan was administered for 9 weeks to ovariectomized (OVX) rats. At necropsy, uterus weights were measured, and trabecular bone areas (TBAS) of tibia and the sixth lumbar vertebra were measured by bone histomorphology. The maximum cell proliferation of MG-63 caused by extract of yukmijiwhang-whan at $5\;{\times}\;10^{-6}\;mg/ml$ was approximately 115% compared with control. In Saos-2, cell proliferation was approximately 145% of control at $5\;{\times}\;10^{-4}\;mg/ml$ and maximum alkaline phosphatase (ALP) activity was approximately 143% of control at $5\;{\times}\;10^{-5}\;mg/ml$. In animal study, however, the tibia and lumbar TBAS of the yukmijiwhang-whan group did not increased than the OVX control group. In conclusion, the 80% EtOH extract of yukmijiwhang-whan increased proliferation of osteoblasts but did not prevent bone loss in OVX rats.

• Korean Chemical Engineering Research
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• v.58 no.3
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• pp.381-389
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• 2020

This study analyzed the optimal electricity cost of a 100% renewable energy source (RES) based system. Especially energy storage system (EES) and supplementary biopower system as well as photovoltaic (PV) and wind power component were included in the proposed RES-based system to overcome the intermittence of RESs and to efficiently balance energy supply and demand. To comparatively analyze the levelized cost of electricity (LCOE) of different RES-based systems, six scenarios were developed according to the involved RESs: PV, wind, PV/wind, PV/biopower, wind/biopower, and PV/wind/biopower systems. We then applied the proposed systems to build a 100% RES-based system in Jeju Island, Korea. As a result, the single component based system, PV and wind power system of 0.18 and 0.28 $/kWh, respectively, cannot compete with the economics of existing electricity grid. However, the optimal LCOE of the hybrid system where PV and wind power are used as main supply options and biopower as supplementary option was identified to be 0.08 $/kWh, which can compete with the economics of an existing electricity grid.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.410-420
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• 2016

Recently, the R&D paradigm has become oriented toward convergence technology and interdisciplinary research. In this study, to elucidate the characteristics of research groups that promote the performance of convergence research, we take into account the input characteristics, disciplinary characteristics and collaborative characteristics of research groups. For this study purpose, 5,217 SCI papers published from 104 centers in Advanced Research Center Projects are analyzed as research outputs. The research findings are that the disciplinary balance in the interdisciplinary characteristics and the number of partners in the collaborative characteristics are positively related to the convergence of R&D outputs. The research field of a group introduced as a control variable exerts a significant effect on the convergent R&D outputs. In conclusion, it is necessary to organize internally with the same number of each disciplinary researcher in a research group and to activate external collaboration with partners in order to produce more outputs of convergent research.