• Journal of the Korean Applied Science and Technology
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• v.23 no.2
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• pp.110-114
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• 2006

The high-solid coatings were prepared by blending the synthesized acrylic resin in the previous paper, and hexamethylene diisocyanate-trimer and curing it at room temperature. The characterization of the films of the prepared coatings was performed. The $60^{\circ}$ specular gloss, impact resistance, cross-hatch adhesion, and heat resistance of the films proved to be good, and the pencil hardness, drying time, and pot-life proved to be slightly poor. From a viscoelastic measurement using a rigid-body pendulum, curing was accelerated with the Tg value.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.1
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• pp.47-55
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• 2009

Sewers are important national infrastructure and play an essential part by handling both wastewater and stormwater to minimise problems caused to human life and the environment. However, they can cause urban flooding when rainfall exceeds the system capacity. Sewer flooding is an unwelcome and increasingly frequent problem in many urban areas, and its frequency will increase over time with urbanisation and climate change. Under current standards, sewers are designed to drain stormwater generated by up to 10 year return period storms, but data suggests that many in practice have been experienced flooding with exceeding system capacity under increased storm events. A large number of studies has considered upgrading or increasing the design standard but there are still lack of information to propose a suitable return period with the corresponding system quantity to achieve. A methodology is required to suggest a proper level of standard within a suitable sewerage rehabilitation planning that can avoid the exceedance problem. This study aimed to develop a methodology to support effective sewer rehabilitation that could prevent urban flooding mainly resulted from the exceedance of existing storm sewer system capacity. Selected sewerage rehabilitation methods were examined under different storm return periods and compared to achieve the best value for money.

• Journal of Applied Reliability
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• v.4 no.2
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• pp.73-90
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• 2004

We performed the heat aging test to predict the useful lifetime of Elastomeric Bearing Chloroprene Rubber (CR) used for supporting bridge. During the test, we measured elongation that are influenced by temperature and aging time. The failure of a test piece is defined as the point at which the elongation reaches to 75% of the initial value. This failure criterion is based on KS F 4420: 1998 (Elastomeric Bearing for bridge). Through the accelerated heat aging test, we found that the Arrhenius relationship and the Weibull lifetime distribution are appropriate as the life-temperature relationship and lifetime distribution of the CR, respectively. Using the Arrhenius -Weibull model, the parameters of the model are estimated and the lifetime of the CR at use condition is predicted.

• Journal of Families and Better Life
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• v.33 no.1
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• pp.1-17
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• 2015

This study investigated how variables of internalizing and externalizing problematic behaviors change according to gender and as time passes by and how the variables influence adolescent problematic behaviors. The variables selected for the analysis are personal variables, parent variables, peer and school variables, and community variables. longitudinal data collected for 4 years from the Korea Youth Panel Survey(KYPS) were utilized for the analysis. Data were collected initially from 2,707 fifth grade elementary students in 2005 and they were traced until 2008. The final respondents were 2,448 students. The findings are as follows. Frist, the statistical significance was found in changes of problematic behavioral variables in terms of the gender difference. Second, variables, such as self-esteem and self-control are negatively correlated to the problematic behaviors and stress level is strongly positively correlated to the behaviors. Third, the study pressure and peer attachment level are correlated to the initial value of internalizing problematic behaviors. In conclusion, given that more statistical significances were found at initial values than the change rates among variables, early intervention is important in addressing adolescent problematic behaviors.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.98-104
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• 2003

While the impact or internet on our everyday life keeps increasing, the internet users are turning toward the value added information only that suits their purpose instead of just wandering over a sea (pool) or information. Although it is easy to locate the information using various search engines. we still finds it time and cost consuming to update the existing information or to add similar Information. There are several portal sites managed by each industrial types or associations/organizations for the purpose or strengthening the competitiveness or small and medium-sized enterprises And currently, tremendous manpower and expenses are put into the selection and quality improvement or information to satisfy the needs toward the high qualify information by the specialized users in their fields collection and updating or the information is partially available manually during He period or budget allocation by the government it becomes problematic, however, to continue this service when the project expires. This report presents the system for the information collection, analysis and classification of portal sites operated for the special purposes and automatic upload to the proper sites. In addition. expression or web robots and application of robots and several information types are suggested which will eventually accomplish currency or information and automatic updates and addition or documents with the least expenses or maintenance.

• Korean journal of food and cookery science
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• v.24 no.6
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• pp.735-741
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• 2008

The principal objective of this study was to evaluate the quality characteristics of yogurt to which had been added extracts of low quality dried persimmons, in an attempt to expand the range of use of low-quality dried persimmons. In the results of our sensory evaluation, our optimal results were attained with the addition of 5 g of dried persimmon extracts, 90 g of water, 20 g of oligosaccharide, and 50 g of fructose at a specific level of 1000 mL. During the 20-day storage period, the pH value of the dried persimmon yogurt was lowest on the 15th day in the control group and the 20th day in the yogurt to which 0.5% extract had been added. The titratable acidity was lowest by a significant margin on the 10th day for all types of yogurt. Viscosity assays showed a stable level of acidity over different storage periods. The number of viable cells demonstrated a trend toward increase with passing time, and the number of viable cells in the dried-persimmon yogurt was higher than that in the control yogurt.

• The Korean Journal of Malacology
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• v.17 no.2
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• pp.95-104
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• 2001

To determine optimal conditions for measurement of the clearance rate in feeding experiment of an intertidal bivalve Glauconome chinensis, effects of starvation, extent of mixing at subsampling, and initial prey concentration were assessed. Experiments were conducted separately for each condition with different treatments. Two-way ANOVAs showed that there were significant differences in clearance rates among different starvation periods (p<0.001), extents of mixing (p = 0.005), and prey concentrations (p < 0.001). Starvation for 1 or 2 days gave rise to 2 to 3-fold increase in the clearance rate. After starvation for 5 days, the clearance rate decreased seriously, implying loss of physiological status. It is suggested that animals should be fed during acclimation. The differences of the clearance rates between gentle and vigorous mixings were significant, but the differences were smaller than that among different incubation times. It was found that vigorous mixing is not necessary. The effect of initial prey concentration was great. However, optimal prey concentration could not be determined at any fixed value. Experiments with multiple concentrations of algal prey are recommended. Optimal incubation time for measurement of the clearance rate of G. chinensis was determined to be 2-4 hours.

• Agricultural and Biosystems Engineering
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• v.1 no.2
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• pp.100-105
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• 2000

Quality sorting of cut flowers is very essential to increase the value of products. There are many factors that determine the quality of cut flowers such as length, thickness, and straightness of stem, and color and maturity of bud. Among these factors, the straightness of stem and the maturity of bud are generally considered to be more difficult to evaluate. A prototype grading and sorting machine for cut flowers was developed and tested for a rose variety. The machine consisted of a chain-drive feed mechanism, a pneumatic discharge system, and a grading system utilizing color image processing and neural network. Artificial neural network algorithm was utilized to grade cut roses based on the straightness of stem and maturity of bud. Test results showed 89% agreement with human expert for the straightness of stem and 90% agreement for the maturity of bud. Average processing time for evaluating straightness of the stem and maturity of the bud were 1.01 and 0.44 second, respectively. Application of neural network eliminated difficulties in determining criteria of each grade category while maintaining similar level of classification error.

• Fisheries and Aquatic Sciences
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• v.23 no.9
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• pp.21.1-21.10
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• 2020

Background: This study aimed to provide a basic standard for assessing freshness and acceptability of whiteleg shrimp (Litopenaeus vannamei). Methods: It was divided into whole body and meat and stored at 25 ℃ to evaluate both quality and freshness changes that occur over time. The shelf life of shrimp was estimated as 17 and 20 h for whole body and meat, respectively. Results: In chemical analysis, K-value increased from 9.96 to 12.32% to a maximum of 75.14%, and TVB-N increased from 1.86 mg/100 g to 34.71 mg/100 g. For volatile sulfur compounds, methyl mercaptan and dimethyl disulfide increased from 0.00 mg/100 g to 1.10 mg/100 g and 1.26 mg/100 g, respectively, rapidly increasing with decreasing freshness. Conclusion: Changes in all biochemical indicators significantly correlated with the sensory evaluation results. This study contributes to the knowledge about whiteleg shrimp spoilage and freshness, providing a basis for developing methods to improve shrimp quality control and management.

• Natural Product Sciences
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• v.19 no.1
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• pp.66-70
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• 2013

Ten compounds (1 - 10), palmitic acid (1), 10-nonacosanol (2), pentacosan-1-ol (3), phytol (4), ${\beta}$-sitosterol (5), ${\beta}$-sitosterol-3-O-${\beta}$-D-glucopyranoside (6), 2,4-dihydroxycinnamic acid (7), hyperoside (8), uridine (9) and adenosine (10), were isolated from the n-hexane and EtOAc-soluble fractions of the aerial parts of A. dioicus var. kamtschaticus (Rosaceae). The structures of these compounds were elucidated on the basis of spectroscopic evidence. All compounds (1 - 10) were isolated for the first time from this plant. Cytotoxicity of 1 - 10 against Jurkat T (T-lymphocytic leukemia cells), HeLa (Human cervical epitheloid carcinoma cells), MCF-7 (Human breast cancer cells), and HL-60 (Human promyelocytic leukemia cells) cell lines was measured. Compound 6 showed good cytotoxicity against HL-60 cell line with $IC_{50}$ value of 8.13 ${\mu}g/mL$. In addition, compounds 7 and 8 exhibited antioxidant activity with $IC_{50}$ values of 16.30 and 12.42 ${\mu}g/mL$, respectively.