• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.255-262
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• 2010

This study was conducted at 5 sites of Bocheong Stream basin in May and September 2009 for the evaluate of fish assemblage and chemical water quality. For the study, the models of Index of Biological Integrity (IBI) and Qualitative Habitat Evaluation Index (QHEI) were modified as 8 and 11 metric attributes, respectively. We also analyzed patterns of chemical water quality at the sampling site over the period of 2005~2009, using the water chemistry dataset, obtained from the Ministry of Environment, Korea. The survey showed that total sampled fishes were 34 species and the most dominant species was Zacco platypus (24.3%). In Bocheong Stream basin, values of IBI averaged 28 (n=5), which is judged as a "Good". IBI score at B1, B4 and B5 indicating a "Good" condition whereas, B2 and B3 were as 21 and 22, indicating "Fair" condition, respectively. QHEI was 152 (n=5), judged as "Fair" habitat condition. Values of BOD and COD averaged 1.0 $mgL^{-1}$ (scope: 0.3~4.0 $mgL^{-1}$) and 2.3 $mgL^{-1}$ (scope: 0.3~18.7 $mgL^{-1}$), respectively. Total nitrogen (TN), total phosphorus (TP) and suspended solid (SS) were distinct spatial variation. Based on the IBI, QHEI and chemical water quality dataset, ecological health of Bocheong Stream basin was evaluated that generally good.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.9
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• pp.56-65
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• 2005

A dynamic analysis method that freezes a time domain by discretization and solves the spatial propagation equation has a unique feature that provides a degree of freedom on spatial domain compared with the space discretization or space-time discretization finite element method. Using this feature, the time finite element analysis can be effectively applied to optimize the spatial characteristics of distributed type actuators. In this research, the time domain finite element method was used to discretize the model. A state variable vector was used in the discretization to include arbitrary initial conditions. A performance index was proposed on spatial domain to consider both potential and vibrational energy, so that the resulting shape of the distributed actuator was optimized for dynamic control of the structure. It is assumed that the structure satisfies the final rest condition using the realizable control scheme although the initial disturbance can affect the system response. Both equations on states and costates were derived based on the selected performance index and structural model. Ricatti matrix differential equations on state and costate variables were derived by the reconfiguration of the sub-matrices and application of time/space boundary conditions, and finally optimal actuator distribution was obtained. Numerical simulation results validated the proposed actuator shape optimization scheme.

• Journal of Korea Water Resources Association
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• v.46 no.12
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• pp.1249-1263
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• 2013

In order to minimize the damages caused by long-term drought, appropriate drought management plans of the basin should be established with the drought forecasting technology. Further, in order to build reasonable adaptive measurement for future drought, the duration and severity of drought must be predicted quantitatively in advance. Thus, this study, attempts to forecast drought in Korea by using an Artificial Neural Network Model, and drought index, which are the representative statistical approach most frequently used for hydrological time series forecasting. SPI (Standardized Precipitation Index) for major weather stations in Korea, estimated using observed historical precipitation, was used as input variables to the MLP (Multi Layer Perceptron) Neural Network model. Data set from 1976 to 2000 was selected as the training period for the parameter calibration and data from 2001 to 2010 was set as the validation period for the drought forecast. The optimal model for drought forecast determined by training process was applied to drought forecast using SPI (3), SPI (6) and SPI (12) over different forecasting lead time (1 to 6 months). Drought forecast with SPI (3) shows good result only in case of 1 month forecast lead time, SPI (6) shows good accordance with observed data for 1-3 months forecast lead time and SPI (12) shows relatively good results in case of up to 1~5 months forecast lead time. The analysis of this study shows that SPI (3) can be used for only 1-month short-term drought forecast. SPI (6) and SPI (12) have advantage over long-term drought forecast for 3~5 months lead time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03a
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• pp.16-16
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• 2010

GaN-based light-emitting diodes (LEDs) are attracting great interest as candidates for next-generation solid-state lighting, because of their long lifetime, small size, high efficacy, and low energy consumption. However, for general illumination applications, the external quantum efficiency of LEDs, determined by the internal quantum efficiency (IQE) and the light extraction efficiency, must be further increased. The IQE is determined by crystal quality and epitaxial layer structure and high value of IQE more than 70% for blue LEDs have been already reported. However, there is much room for improvement of light extraction efficiency because most of the generated photons from active layer remain inside LEDs by total internal reflection at the interface of semiconductor with air due to the high refractive index difference between LEDs epilayer (for GaN, n=2.5) and air (n=1). The light confining in LEDs will be reabsorbed by the metal electrode or active layer, reducing the efficacy of LEDs. Here, we present the first demonstration of enhanced light extraction by forming a MgO nano-pyramids structure on the surface of vertical-LEDs. The MgO nano-pyramids structure was successfully fabricated at room temperature using conventional electron-beam evaporation without any additional process. The nano-sized pyramids of MgO are formed on the surface during growth due to anisotropic characteristics between (111) and (200) plane of MgO. The ZnO layer with quarter-wavelength in thickness is inserted between GaN and MgO layers to increase the critical angle for total internal reflection, because the refractive index of ZnO (n=1.94) could be matched between GaN (n=2.5) and MgO (n=1.73). The MgO nano-pyramids structure and ZnO refractive-index modulation layer enhanced the light extraction efficiency ofV-LEDs with by 49%, comparing with the V-LEDs with a flat n-GaN surface. The angular-dependent emission intensity shows the enhanced light extraction through the side walls of V-LEDs as well as through the top surface of the n-GaN, because of the increase in critical angle for total internal reflection as well as light scattering at the MgO nano-pyramids surface.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.4
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• pp.473-480
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• 2017

The aim of this study was to investigate the effects of gluten and moisture contents on the physical properties of extruded soy protein isolate. Extrusion conditions included various moisture (45, 50, and 55%) and gluten contents (20, 40, and 60%) at a fixed screw speed and die temperature of 250 rpm and $140^{\circ}C$, respectively. Specific mechanical energy input decreased as gluten content increased from 20 to 60%. Hydration ratio was highest ($293.23{\pm}13.68%$) at gluten and moisture contents of 20 and 55%, respectively. Lightness and yellowness increased as gluten content increased from 20 to 60% while redness decreased as gluten content increased. Color difference was the highest at low gluten and moisture contents. Integrity index was the highest ($71.15{\pm}0.93%$) at gluten and moisture contents of 60 and 45%, respectively. Nitrogen solubility index was not significantly affected by moisture content and was lowest ($22.46{\pm}1.11%$) at gluten and moisture contents of 60 and 55%, respectively. In conclusion, higher gluten and lower moisture contents were effective for texturization of soy protein isolate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.5
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• pp.616-621
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• 2017

The objective of this study was to investigate the physicochemical properties of domestic strong wheat flour (DSWF). Three commercial DSWFs (D1, D2, and D3) were compared with imported strong wheat flour (ISWF). DSWFs had higher moisture content, crude protein content, lightness, and whiteness than ISWF. DSWFs showed lower solvent retention capacity and water absorption index than ISWF. DSWFs also showed significantly higher water solubility index than ISWF (P<0.05). Setback values by rapid visco analysis were significantly higher in D1 and D2 than in ISWF and D3, which means ISWF and D3 were better in retarding retrogradation. Differential scanning calorimetry results showed that ISWF required 6.2 J/g of energy for phase transition, whereas DSWFs needed 6.67~7.13 J/g. The farinograph results showed that ISWF had higher water absorption, longer dough stability time, and significantly higher softening of dough at 20 min than DSWF (P<0.05). Dough resistance and extensibility were higher in ISWF than in DSWFs.

• Science of Emotion and Sensibility
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• v.17 no.3
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• pp.95-106
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• 2014

This research analyzed biosignals associated with the change of emotion from lighting felt by the occupants and task type under various indoor thermal environments and illuminance, and examined the biosignals' impacts on work. To this end, the indoor thermal environment was constructed on the basis of PMV (predicted mean vote) index value, and various indoor environments were created by changing the brightness of LED stands. In this manner, a variety of indoor environments were constructed, and experiments were carried out. This research evaluates the sensibility response to lighting through a questionnaire survey in the given environment and incorporates different types of error searches. In this way, changes were analyzed by measuring electroencephalogram (EEG) and electrocardiograms (ECG). As a result, all biosignals on the task type showed significant differences from the thermal environment change. When PMV index value was 0.8 (temperature: $25^{\circ}C$, humidity: 50 %), concentration and attention were the most activated. However, the biosignals did not show significant differences from the illuminance change. Concentration on an occupant's work capability was confirmed to be closely related to the thermal environment. As for the subjective emotional response to lighting, the occupants felt comfort as illuminance was lower, while they felt discomfort as illuminance was higher. However, there were no significant differences from the thermal environment change.

• Journal of Korean Society of Transportation
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• v.35 no.3
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• pp.169-182
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• 2017

This research reviews regulations on logistics/transport industry and attempts to quantify the effects of regulation mitigation on GDP per capita. South Korea's transport industry has been gradually expanding, however, the industrial structure is still short rooted. In 2014, average number of hours worked is 5th highest and wage margin 12th smallest out of 18 industries. Furthermore, the regulations for this industry appear to be stricter than those of other industries. OECD's logistics/transport industry regulatory index for South Korea has been decreasing for the last 40 years but still exceeds those of EU, Japan, US, and other countries. This paper provides supporting reasons for regulatory reforms by analyzing the ripple effects on real GDP. Factors such as the ratio of trade among GDP, the enrollment rate to primary school, energy usage per capita, and population are controlled in the fixed-effect model. Estimation results showed that 1 unit decrease in transport/logistics regulatory index is correlated with 8.1% increase of the real GDP per capita, that is, 10% of deregulation is expected to yield 2.16% increase in GDP per capita. Thus, it is expected that mitigating regulations on market entries, price determination, ownership structures of network industry, vertical integrations can improve the economy of South Korea.

• Journal of the Korean Society for Railway
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• v.15 no.3
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• pp.286-293
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• 2012

Korean government is enforcing 'Greenhouse gas target management' in order to achieve Greenhouse gas reduction target. To attain Greenhouse gas reduction target, companies in Korea must establish their GHG inventory system and analysis their GHG emissions characteristics for deduction of mitigation measures. LMDI(Log Mean Divisia Index) decomposition analysis is widely used to understand characteristics of GHG emission and energy consumption. In this paper, the characteristics of GHG emission from the line of railroad in Korea is respectively analyzed in terms of conversion effect, intensity effect, production effect and distance effect. Data of railroad GHG emission from 2000 to 2007 are used. As a result, total effect of railroad's GHG emission is $96,813tCO_2eq$. Production effect ($39,865tCO_2eq$) and distance effect ($327,923tCO_2eq$) affect increase of railroad GHG emissions while Conversion effect ($-158,161tCO_2eq$) and intensity effect ($-112,814tCO_2eq$) influence decrease of the emissions.

• Korean Journal of Community Nutrition
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• v.27 no.2
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• pp.81-93
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• 2022

Objectives: This study was conducted to investigate the experience and perception among adult women regarding weight control and the consumption of weight-control foods or health functional foods based on their body mass index (BMI). Methods: The subjects were 634 adult women from the Chungcheong province, Korea, and data were collected through a self-administered questionnaire from July 2021 through September 2021. The subjects were divided into four groups based on their BMI status: underweight (< 18.5 kg/m², 7.6%), normal weight (18.5 ~ 22.9 kg/m², 53.3%), overweight (23 ~ 24.9 kg/m², 19.7%), and obese (≥ 25 kg/m², 19.4%). Results: Over the past 3 years, almost two-thirds (68.6%) of the adult women had tried weight control measures, despite the fact that a significant proportion of them were normal or underweight. More importantly, 57.6% of subjects reported the consumption of weight-control foods, with a lower proportion in the underweight (35.4%) group compared to the normal (56.2%), overweight (62.4%), and obese (65.0%) groups. The food items used for weight control were mostly salads, chicken breasts, low fat (soy) milk, slimming tea, protein shakes, low-calorie cereals, and energy/protein bars among others. In addition, one-third (31.1%) of the subjects reported the use of health functional foods containing ingredients for fat reduction. A significantly higher proportion of these was from the overweight (36.0%) and obese (38.2%) groups compared to the underweight (20.8%) and normal weight (28.1%) groups. Products containing Garcinia cambogia extract, green tea, or Cissus extract, were popular among users. Subjects who were obese had a poorer perception of their health and body. Most subjects felt the need for correct information regarding weight control, but this number was significantly more in the higher BMI groups. Conclusions: Our results suggest that the use of weight-control foods or health functional foods is popular among adult women, especially those who are obese. Thus, nutrition education courses covering facts about weight control and practice need to be developed and provided based on the BMI status of subjects.