• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.429-437
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• 1999

A mathematical model was established for estimating changes in pressure and volume of permeable kimchi packages. The model comprises the CO2 gas production from kimchi and permeation of O2, CO2 and N2 through the permeable film or sheet. Using the developed model, the effects of various packaging variables on the pressure and volume changes were analyzed for rigid and flexible packag es of kimchi(3% salt content) at 15oC, and then effect of storage temperature was also looked into. In case of rigid pack of 400g, using the plastic sheet of high CO2 permeability and initial vacuumizing can help to relieve the problem of pressure build up. The lower fill weight can further reduce the pressure, but will result in higher packaging cost. For the flexible package of 3 kg, highly permeable films such as low density polyethylene(LDPE) and polypropylene can reduce the volume expansion. Higher ratio of CO2 permeability to O2 and N2 permeabilities are effective in reducing the volume expansion. Increased surface area cannot contribute to reduction of volume expansion for highly permeable flexible packages of kimchi. For the impermeable packages, pressure and volume at over ripening stage (acidity 1.0%) increase with decreased temperature, while those at optimum ripening stage(acidity 0.6%) change little with temperature. Pressure of permeable rigid LDPE package increases with tem perature at any ripening stage, and temperature affects the volume of flexible LDPE package very slightly. Experimental verification of the present results and package design with economical consid eration are needed as a next step for practical application.

• Journal of Wetlands Research
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• v.19 no.3
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• pp.271-278
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• 2017

Low impact development (LID) technology has been recently applied for the treatment of nonpoint source pollutants. Rain garden is one of the widely used LIDs since it utilizes various mechanisms such as biological and physico-chemical treatment to reduce pollutants. However, problem such as clogging has been one of the issues encountered by the rain garden that do not undergo constant maintenance. Therefore, this research was conducted to develop and determine the component arrangement of a rain garden system for a more efficient volume and pollutant reduction. Two hybrid rain garden systems having different characteristics were developed and evaluated to determine the optimum design and arrangement of the system. The results showed that the components arranged in a series manner showed a volume reduction of 93% and a pollutant reduction efficiency of approximately 99%, 93% and 95% was observed for particulates, nutrients and heavy metals, respectively. While when the system is connected in a combined series-parallel, the volume and average pollutant reduction efficiency for the TSS, nutrients and heavy metals are 65%, 94%, 80% and 85%, respectively. Moreover, the component arrangement in the order of sedimentation tank, infiltration tank and plant bed exhibited a high pollutant reduction efficiency compared when the infiltration tank and plant bed were interchanged. The findings of this research will help in the further development and optimization of rain garden systems.

• KIEAE Journal
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• v.12 no.4
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• pp.77-82
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• 2012

This study conducted the experiment of reduction of Volatile Organic Compounds(VOCs) and Formaldehyde concentration by Native plants, Fatsia japonica and Ardisia pusilla. The two plants are advantageous in that they are highly available as they grow wild, and being easy to get. Fatsia japonica is a plant of its wide and large leaf diverged 7 or 8 parts, which is thought to have a high effect of air purification. Ardisia pusilla has a smaller leaf than Fatsia japonica, which is characterized by more leaves and beautiful. Field measurements were performed using Fatsia japonica and Ardisia pusilla which were verified as air-purifying plants in Korea. The effect of reducing the concentration of VOCs and Formaldehyde by plant studied in a full scale mock-up model. The dimensions of the two models were equal. The concentration of Benzene, Toluene, Ethylbenzene, Xylene, Stylene, Formaldehyde were monitored, since they were known as most toxic materials. The concentration of VOCs was monitored three hours after the plants were placed and three days after the plants were placed. Field measurements were performed in models where the plants were placed and were not. As a result, they had all an effect of reducing pollution. In all cases of experiment of planting and growing volume, the more planting volume, the more excellent the effect. Toluene was more effective in Fatsia japonica and Ardisia pusilla planted, Formaldehyde was more effective in Fatsia japonica planted respectively. In planting and growing and placing experiment, the placement at sunny spot was more effective than that at scattered growing. When Fatsia japonica was placed at sunny spot, the reduction effect of Formaldehyde was the most excellent, and when Ardisia pusilla was placed at sunny spot, the reduction effect of Toluene was the most effective.

• Journal of Korean Public Health Nursing
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• v.28 no.1
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• pp.22-31
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• 2014

Purpose: The purpose of this study was to examine the impact of body mass index (BMI) and waist circumference (WC) for pulmonary function in normal-weight and obese women. Methods: Data from women aged ${\geq}40$ years were obtained from the 2011 Korean National Health and Nutrition Examination Survey. Obesity was measured by BMI and WC and pulmonary function was measured by forced vital capacity (FVC), forced expiratory volume in 1 second ($FEV_1$), and a ratio between forced expiratory volume in 1 second ($FEV_1$/FVC). Multiple linear regression analysis was performed for assessment of the association between FVC, $FEV_1$, $FEV_1$/FVC and obesity variables. Results: BMI showed positive association with FVC, $FEV_1$, $FEV_1$/FVC, and WC showed positive association with $FEV_1$ and $FEV_1$/FVC in normal-weight women. BMI and WC showed negative association with FVC, $FEV_1$ in obese women. A 1 unit increase in BMI showed an association with a 25-mL reduction in FVC and a 19-mL reduction in $FEV_1$. A 1-cm increase in WC showed an association with a 6-mL reduction in FVC and a 4-mL reduction in $FEV_1$. Conclusions: BMI and WC showed negative association with pulmonary function in obese adult women. Therefore, obese women with reduced pulmonary function should be encouraged to lose weight for improvement of their pulmonary function.

• Journal of Climate Change Research
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• v.7 no.1
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• pp.85-93
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• 2016

This study the efficiency of greenhouse gas reduction of 'low carbon car collaboration fund' and its alternative 'control of average fuel efficiency and greenhouse gas', and 'improving driving behavior' were analyzed by using LEAP, long term energy analysis model. Total 4 scenarios were set, baseline scenario, without energy-saving activity, 'low carbon car collaboration fund' scenario, 'fuel efficiency improving scenario', and 'improving driving behavior' scenario. The contents of analysis were forecast of energy demand by scenario and application as well as reduction of greenhouse gas emission volume, and the period taken for analysis was every 1 year during 2015~2030. Baseline scenario, greenhouse gas emission volume in 2015 would be 7,935,697 M/T and 13,081,986 M/T in 2030, increased 64.8%. The analysis result was average annual increase rate of 3.4%. The expected average annual increase rate of other scenarios was, 'low carbon car collaboration fund' scenario 1.7%, 'fuel efficiency improving' scenario 3.0%. and 'improving driving behavior' scenario 3.4%. and these were each 1.7%, 0.3%. 0.3% reduce from baseline scenario. The largest reduction was 'low carbon car collaboration fund' scenario, and there after were 'fuel efficiency improving scenario', and 'improving driving behavior' scenario.

• The Journal of Advanced Prosthodontics
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• v.16 no.2
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• pp.91-104
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• 2024

PURPOSE. The objectives of the current study were to estimate the influence of self-reinforced hollow structures with a graded density on the dimensional accuracy, weight, and mechanical properties of Co-Cr objects printed with the direct metal laser sintering (DMLS) technique. MATERIALS AND METHODS. Sixty-five dog-bone samples were manufactured to evaluate the dimensional accuracy of printing, weight, and tensile properties of DMLS printed Co-Cr. They were divided into Group 1 (control) (n = 5), Group 2, 3, and 4 with incorporated hollow structures based on (spherical, elliptical, and diamond) shapes; they were subdivided into subgroups (n = 5) according to the volumetric reduction (10%, 15%, 20% and 25%). Radiographic imaging and microscopic analysis of the fractographs were conducted to validate the created geometries; the dimensional accuracy, weight, yield tensile strength, and modulus of elasticity were calculated. The data were estimated by one-way ANOVA and Duncan's tests at P < .05. RESULTS. The accuracy test showed an insignificant difference in the x, y, z directions in all printed groups. The weight was significantly reduced proportionally to the reduced volume fraction. The yield strength and elastic modulus of the control group and Group 2 at 10% volume reduction were comparable and significantly higher than the other subgroups. CONCLUSION. The printing accuracy was not affected by the presence or type of the hollow geometry. The weight of Group 2 at 10% reduction was significantly lower than that of the control group. The yield strength and elastic modulus of the Group 2 at a 10% reduction showed means equivalent to the compact objects and were significantly higher than other subgroups.

• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.143-155
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• 2016

Recently, a massive loss of life and property is occurring in Korea due to traffic accidents, with the rapid increase in cars. For improvement of traffic safety, the Korea Transportation Safety Authority intensively analyzes accident data in local governments with low traffic safety index, performs a field investigation to extract problems and offers local governments improvements for problems, by conducting the 'Special Survey of Actual Conditions of Traffic Safety' each year, starting 2008. But local governments cannot strongly push forward the improvement projects due to the limited budget and the uncertainty of the improvement plan effects. Therefore, this study suggested a model which applied the Utility concept to the AHP theory, in order to efficiently decide a priority of the improvement plans in accident black spots in consideration of the limited budget of local governments. The number of accidents in each spot for improvement and accident severity, traffic volume, pedestrian volume, the improvement project cost and the accident reduction effect were chosen as evaluation factors for deciding a priority, and data about the improvement plan costs and the accident reduction effects, traffic accidents and traffic volume in the spots to undergo the special research on the real condition of traffic accident in the past were collected from the existing studies. Then, regression analysis was carried out and the Utility Curve of each evaluation factor was computed. Based on the AHP analysis findings, this study devised a priority decision method which calculated the weight and the utility function of each evaluation factor and compared the total utility values. The AHP analysis findings showed that among the evaluation factors, accident severity had the biggest importance and it was followed by the improvement plan cost, the number of accidents, the improvement effect, traffic volume and pedestrian volume. The calculated utility function shows a rise in utility, as the variables of the 5 evaluation factors; the number of accidents, accident severity, the improvement plan effect, traffic volume and pedestrian volume increase and a fall in utility, as the variables of the improvement plan cost increase, since the improvement plan cost is included in the budget spent by a local government.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.63-67
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• 2001

Since the transportation cost takes about two thirds of the logistics cost of Korean firms, significant reduction of business logistics cost can hardly be achieved without effectively reducing the transportation cost. Although consolidated transportation has been regarded as the most promising strategy for reducing the transportation cost, it has not been successful in practice. In this paper we consider a consolidated transportation for the factories located in a limited area such as industrial complexes, where loads of various volume and weight are consolidated. We want to group the loads to assign to a truck of various size such that the total transportation cost is minimized, while the maximum volume constraint and weight constraint of each truck are satisfied. We suggest four heuristic algorithms to efficiently determine the groups of loads; and conduct a computer simulation to evaluate the performances of the algorithms.

• Transactions of Materials Processing
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• v.13 no.4
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• pp.350-358
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• 2004

The effects of alloying elements on microstructural features and mechanical properties in 0.55%C medium carbon steels were investigated. The samples were austenitized at 105$0^{\circ}C$ for 30min. followed by quenching in a salt bath in the temperature range of 500 ~ $620^{\circ}C$. The addition of Cr resulted in the decrease of the volume fraction of pro-eutectoid ferrite and interlamellar spacing in pearlite and the increase of strength. However, the addition of B caused the increase of the volume fraction of pro-eutectoid ferrite. Reduction of area and Charpy impact values were influenced by the combined effect of microstructural features, such as the volume fraction of pro-eutectoid ferrite, interlamellar spacing and the thickness of lamellar cementite in pearlite.

• 한국전산유체공학회:학술대회논문집
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• 2006.10a
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• pp.22-25
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• 2006

Direct simulations of aerodynamic sound, especially sound emitted by rapidly rotating elliptic cylinder by the finite difference lattice Boltzmann method (FDLBM). Effect of pile-fabrics for noise reduction is also studied by the finite volume LBM (FVLBM) using an unstructured grid. Second order time integration and third order upwind scheme are shown to be enough for these simulations. Sound sources are detected to be doublets for both cases. For the elliptic cylinder, the doublet is generated in the interaction between the vortex and the edge. For the circular cylinders, they are generated synchronizing with the Karman vortex street, and it is also shown that the pile-fabrics covering the surface of the cylinder reduces the strength of the source.