• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.4
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• pp.205-212
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• 2021

Offshore jacket structures generally comprise steel members, and the safety standard for jacket structures typically focuses on the steel components. However, large amounts of concrete grouting is filled in the legs of the Gageocho jacket structure to aid in the recovery from typhoon damage. This paper proposes a safe and lightweight design for the Gageocho ocean research station comprising steel members instead of large amounts of concrete reinforcement in the legs. Based on the actual design, the structural members are grouped according to their functional roles, and the inner diameter of the cross-section in each design group is defined as a design variable. Structural optimization is carried out using a genetic algorithm to minimize the total weight of the structure. To satisfy the conservative safety standards in the offshore field, both the maximum stress and the unity check criteria are considered as design constraints during optimization. For enhanced safety confidence, extreme environmental conditions are assumed. The maximum marine attachment thickness and the section erosion in the splash zone are applied. Additionally, the design load is defined as the force induced by extreme waves, winds, and currents aligned in the same direction. All the loading directions surrounding the structure are considered to design the structure in a balanced and safe manner. As a result, compared with the current structure, the proposed structure features a 45% lighter design, satisfying the strict offshore safety criteria.

• Journal of Environmental Impact Assessment
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• v.31 no.1
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• pp.47-62
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• 2022

Wind power has been rapidly growing over last decade in the world as well as in South Korea as a feasible renewable energy source. Providing sustainable energy to all while securing environmental sustainability requires evidence based policy making and innovative solutions. Through analysis of 58 cases of South Korean Environmental Impact Assessment (EIA) Report, this paper seeks to identify answers to the following two questions. What are the key characteristics for inland windfarm? Is there a way of measuring environmental sustainability to compare each location to reduce negative environmental impact? Variables related to environmental sustainability of each windfarm case were collected from EIA report and the factor analysis of environmental variables was conducted to calculate the weight for each variable to build environmental sustainability index (ESI) to provide as evidence-based tools for decision making on the location of inland windfarm. 58 cases were categorized as three types 1) Mountain type 2) Ranch Type and 3) Coastal Type depending on their height and degree of naturalness. For analytical research, first, it was successfully calculated environmental sustainability of each windfarm case ranging from 1.04 (#33, Ranch type) to -1.44 (#55, Mountain type). Second, the analysis results showed that ranch type is most environmentally sustainable (Average ESI = 0.4551), followed by coastal type (Ave ESI = 0.3712) and lastly mountain type (Average ESI = -0.3457). These findings are consistent with the previous researches on inland windfarms and provides substantive policy implication on the renewable energy policies.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.1
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• pp.1-8
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• 2023

At construction sites, interest in the production of precast materials is increasing due to off-site conditions due to changes in construction site conditions due to increased labor costs and the Act on the Punishment of Serious Accidents. In particular, the precast prestressed hollow slab has a hollow shape in the cross section, so structural performance is secured by reducing weight and controlling deflection through stranded wires. With the application of structural standards, the urgency of securing fire resistance performance is emerging. In this study, a fire-resistance cross section was developed by reducing the concrete filling rate in the cross section and improving the upper and lower flange shapes by optimizing the hollow shape in the cross section of the slab to have the same or better structural performance and economic efficiency compared to the existing hollow slab. The PC hollow slab to which this was applied was subjected to a two-hour fire resistance test using the cross-sectional thickness as a variable, and as a result of the test, fire resistance performance (load bearing capacity, heat shielding property, flame retardance property) was secured. Based on the experimental results, it is determined that fire resistance modeling can be established through numerical analysis simulation, and prediction of fire resistance analysis is possible according to the change of the cross-sectional shape in the future.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.2
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• pp.153-160
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• 2023

In this study, nano-sized C-S-H crystals were synthesized using the liquid phase reaction method and their properties were investigated. The synthesized C-S-H crystals were added to the cement composite in suspension form to determine their effect on the hydration properties of the cement. The amount of chemical admixture was varied to obtain nano-sized C-S-H crystals with optimal agglomerated morphology, and SEM photographs were analyzed. A cleaning process was added to remove harmful substances other than the synthesiz ed C-S-H crystals. It was found that the concentration of harmful substances was reduced in the case of C-S-H crystals subjected to the cleaning process. The synthesized C-S-H suspensions were prepared with and without the cleaning process, and cement composites were prepared with the cement weight content as the main variable. The effect of C-S-H crystals on the initial hydration properties of the cement was confirmed by microhydration heat analysis. In addition, mortar specimens were prepared to measure the compressive strength over time. The test results showed that the nano-sized C-S-H crystals act as nucleation sites in the cement paste to promote the early hydration of the cement and increase the early compressive strength.

• Journal of Practical Engineering Education
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• v.16 no.3_spc
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• pp.391-399
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• 2024

All highway toll gates in Korea use low-speed WIM(Weight-In-Motion) to block overloaded cargo vehicles from entering the main highway, but some cargo vehicle owners are illegally modifying vehicles to operate variable axles and evading crackdowns by manipulating the axles. In previous studies detect all tires of a running vehicle were detected to determine whether there is axle manipulation. However, because the vehicle entry area at the highway toll gate checkpoint is very narrow, there is a problem that it is realistically difficult to film all tires of the entering vehicle in one video frame. In this paper, we proposed a system that can determine whether the axle is being operated through changes in the height of the vehicle's cargo box rather than by detecting tires. To detect changes in the height of a cargo box, we propose a method to extract the representative line of the cargo box using Hough transform and then measure the change in height of the representative line to detect the change in height of the cargo box. In addition, we propose a method to detect changes in the vertical height of a cargo box by accumulating motion vectors of pixels within a certain area of the image using optical flow. And the two methods were compared and their advantages and disadvantages were analyzed and presented.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.373-383
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• 2012

Soybean, C.V. Daewonkong, was planted on 25 May and 25 June in 2011, and four temperature gradient, control (ambient temperature in field plot), control + $3^{\circ}C$, control + $4^{\circ}C$, and control + $5^{\circ}C$, were artificially created by controlling the green house system. The obtained results indicated that vegetative growth of soybean plant was beneficially facilitated by planting on May (PM) than planting on June (PJ). The 100-seed weight was significantly higher in PM, and positively affected by increasing temperature, whereas the weight was reduced in control + $5^{\circ}C$ plot. Isoflavone content and fatty acid composition were analyzed to determine the effects of plating date and growth temperature. Isoflavone content was higher in PJ plot ($1479.8{\mu}g/g$) than in PM plot ($1201.8{\mu}g/g$), however, the influence of growth temperature varied with planting date. The composition of oleic acid was positively affected by increasing temperature, whereas the proportions of linoleic and linolenic acid were reduced. The numbers of node was considered as a major variable in the regression equations estimated using forward stepwise regression analysis for isoflavone content and unsaturated fatty acid under different environmental conditions.

• Journal of Bio-Environment Control
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• v.16 no.3
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• pp.233-239
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• 2007

This study was carried out to investigate the distribution of ${\alpha}-glucosidase$ inhibitor (AGI) activity and to evaluate horticultural characteristics of pepper (Capsicum spp.). AGI activities of pepper fruits and leaves were different from 1.0 to 20.5 times and 1.0 to 5.9 times, respectively. Weight, length and width of evaluated pepper fruit were distributed from 0.5 to 56.0 g, 0.8 to 15.4 cm and 0.5 to 6.3 cm per fruit respectively. Stem colors before transplanting varied from green to violet. Length and width of leaf were distributed from 3.1 to 5.0 cm and 2.1 to 3.0 cm. Immature fruit color was almost green and mature fruit color was almost red. In horticultural characteristics of selected pepper lines with high AGI activity, the fruit position was downward position. The immature fruit color was green in all lines except one and the mature fruit color was red in all lines. Fruit weight and fruit length of selected pepper lines with high AGI activity were distributed from 5.9 to 41.1 g and 5.9 to 17.0 cm and leaf width and leaf length were distributed from 5.8 to 29.7 cm and 3.9 to 8.7 cm, respectively. The AGI activities of pepper is widely variable between leaf and fruit. According to this result, it suggested the possibility of developing a new pepper line with high AGI activity.

• Korean Journal of Veterinary Service
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• v.29 no.3
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• pp.347-364
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• 2006

This study is concerned with assessment of diethylnitrosamine (DEN 0.01 %) induced liver cell carcinogenesis by measurement of changes preceding the development of neoplasms. Therefore, it was undertaken to investigate changes of liver-specific enzyme activities in Sprague-Dawley (SD) rats by ad libitum feeding of DEN. And also. the changes of hepatic morphology in SD rats were detected by haematoxylineosin stain and immunohistochemistry (PCNA). 5- Fluorouracil (5- FU) is one of the most widely used anticancer agents for digestive cancers including hepatocellular carcinoma, and is known to affect the cell cycle and induce apoptosis of cancer cells. In the present study, SD rats were given drinking water containing 0.01% diethylnitrosamine (DEN) for 8 weeks. Minor behavioral change, brittleness of hair and decreased amount of water and diet intake were observed in rats 4 weeks after DEN administration. The body and liver weights were significantly (p < 0.05) decreased in rats 11 weeks after DEN administration. The liver weight ratio to body weight was rather stable and not significantly decreased in the all treatment groups. The liver specific enzyme activities (AST, ALT, ${\gamma}$-GTP) were significantly increased in all treatment groups compared to control group (p < 0.05). Variable size of liver tumor and hepatomegaly were observed in rats treated with DEN after 10 weeks. Numerous vacuoles were seen on the midzonal and or peripheral areas of hepatic lobules. The large and polymorphological hepatocytes with eosinophilic cytoplasm or densely basophilic mitotic nucleoli were seen. Several proliferative small round cells were seen on vacuolated and necrotic areas in peripheral hepatic lobules or portal areas. PCNA-positive cells were seen on the vacuolated portal areas and peripheral areas of hepatic lobules in the areas of small round cells. We examined functional and morphological changes of livers by 5 - FU treatments on DEN -treated rat. The DEN -treated rats compared to 5 - FU -treated rats after DEN treatment for 8 weeks. The serum total protein and triglyceride were significantly (p < 0.05) decreased, and the liver enzyme activities of AST and ALT were significantly(p < 0.05) increased. After 8 weeks, in the non-5-FU -treated group, the size of liver tumor were varied and hepatomegaly were observed, hepatocellular vacuolization, necrosis and steatosis were observed on the midzonal and peripheral areas of hepatic lobules. The large and polymorphological hepatocytes were seen, the interlobular connective tissues were proliferated. PCNA positive cells were seen in the portal areas and peripheral areas of hepatic lobules in the non-5-FU-treated group. In hepatocytes, condensation of nuclear chromatin and vacuolization were observed, shape of the nuclei were irregular, the degraded nuclei and organelles were observed. The livers of rats in the 5 - FU treatment group were seen grossly brilliant, red-brown color, and the vacuolated and degenerated regions, hyperplastic nodules were not nearly observed. In the electron microscope, the cytoplasm of the hepatocytes contained a large number of mitochondria, rough endoplasmic reticulum, developed organelles surrounding nuclei. The above findings suggest that 5 - FU will be effective as anti -liver tumor drug.

• Journal of agricultural medicine and community health
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• v.39 no.4
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• pp.240-255
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• 2014

Objective: The purpose of this study was to identify the correlates of bone mineral density of Korean adults. Methods: This study was based on the data from the 2010-2011 Korean National Health and Nutrition Examination Survey (KNHANES, 2010~2011) V. Among 8,473 subjects of the survey, who were adults 19 years old or over with bone mineral density data, the current study excluded those whose data include a missing study variable or the response of 'I don't know', and finally analyzed the data of 5,986 subjects (2,692 males and 3,294 females). This study employed the following statistical methods of analysis: t-test, analysis of variance (ANOVA), and hierarchical multivariate linear regression analysis. Results: In multivariate analysis, in the case of men, the significant associated factors in bone mineral density were age, education level, body mass index (BMI), waist circumference, total muscle mass, exercise, and weight control; in the case of women, the significant associated factors in bone mineral density were age, education level, economic activity, BMI, total muscle mass, exercise, weight control. fat intake, uptake female hormone, menopause, and age of menarche. Conclusion: For both sexes, the strongest modifiable factor in influencing bone mineral density was total muscle mass. Therefore, to prevent osteoporosis and promote health, active health education and interventions such as regular exercise for total muscle mass increase should be implemented from an early growth period.

• Journal of Food Hygiene and Safety
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• v.17 no.1
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• pp.1-7
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• 2002

This study was performed to investigate the possibility of water purification by a wild train of Oenanthe javanica DC. Three commercially available dishwashing detergents and a standard surfactant, linear alkylbenzene sulfonate (LAS), were used for this study. The experiment was done in 1.5 ι transluscent aquariums. The plants were distributed into various concentrations of detergents and various kinds of detergent in the separate aquariums. The wet weight of the plants was significantly decreased (p<0.05), and the visual vitality of the plants also decreased in 2 days. The higher the concentration of detergent was, and the more time the plants were exposed to the detergents, the more decrease of growth was observed. The pH value of the culture media decreased in 2 days and in 4 days, then slightly increased in 6 days. However, the pH value of the media did not return to the initial neutral level of pH in 6 days. The pH value of the culture media containing the LAS remarkably increased in 6 days and increased to a neutral pH value in 18 days (p<0.01) as the pH of the other culture media. The chemical oxygen demand (COD) of the culture media gradually increased over the 4 days. A decrease of COD was observed in 6 days, but no tendency was observed between 12 and 18 days. The detergent in the culture media was highly significantly decreased in 2 days (p<0.01) and gradually decreased after this. After 6 days the remaining detergent was 12.4∼23.7% from the various levels of initially added concentration, and 22.4 ∼34.2% from the flour kinds of detergents. These results show that the reduction of detergent was caused by Oenanthe javanica and the effect was significant during the first 6 days when the plants were still growing well. These results indicate that the plant purifies contaminated water for several days and the effect could be variable according to the level of contamination and the environment in which the plant grows.