• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.3
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• pp.256-264
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• 2021

Rapeseed (Brassica napus L.) is generally sown in late autumn and harvested in early summer in Korea, however, spring cultivation has also been attempted in some areas because frequent climate changes induce reducing productivity. Therefore, there is a need for a transplanting technology that is relatively easy to control of cropping season according to changes in cultivation conditions. In this study, to find out the optimal characteristics of seedlings for machine transplanting of spring cultivation, seedling morphological characteristics were investigated according to the seedling age of three varieties for 2020 and 2021. The hypocotyl length was less than 2 cm in both years and the 40-day-old seedling was the shortest among all seedling ages. The number and size of leaf were increased with longer seedling age in both years. To evaluate seedling quality, total seedling length, seedling weight, and impact resistance were measured before transplanting. Total seedling length was the longest in 40-day-old seedlings and the shortest in 25-day-old seedlings in both years. In the case of seedling weight, no significant differences were observed depending on the seedling age and the impact resistance increased with increasing seedling age. Finally, 'Jungmo7001', 'Naehan', and 'Tamla' showed a high transplanting rate in seedlings grown for more than 30 days, 35 days, and 40 days, respectively, in the field using a general transplanter. These results suggest that the proper seedling age for transplanting is limited depending on the rapeseed varieties. The suitable seedling cultivation method can be selected for different cultivation environments.

• Journal of Life Science
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• v.31 no.9
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• pp.840-848
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• 2021

This study was conducted to estimate annual trends and the environmental effects in the racing records of Jeju horses. The Korean Racing Authority (KRA) collected 48,645 observations for 2,167 Jeju horses from 2002 to 2019. Racing records were preprocessed to eliminate errors that occur during the data collection. Racing times were adjusted for comparison between race distances. A stepwise Akaike information criterion (AIC) variable selection method was applied to select appropriate environment variables affecting racing records. The annual improvement of the race time was -0.242 seconds. The model with the lowest AIC value was established when variables were selected in the following order: year, budam classification, jockey ranking, trainer ranking, track condition, weather, age, and gender. The most suitable model was constructed when the jockey ranking and age variables were considered as random effects. Our findings have potential for application as basic data when building models for evaluating genetic abilities of Jeju horses.

• Journal of the Korean Society of Radiology
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• v.15 no.2
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• pp.265-271
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• 2021

The pattern of the tree's internal swelling depends on many causes. Since it is difficult to detect these various causes of swelling with a general method, if the state of swelling for a long time cannot be confirmed, serious damage to the trees may occur due to enlargement of the swelling area. In the method of acquiring a tree tomography image, an impulse passing through the tree is generated by tapping the sensor with a rubber mallet, and the moving speed is recorded. In this paper, to measure cracks, cavities, and swelling due to physical damage, we developed a 3D viewer that can know the internal state of a tree using a tree cross-section image acquired from Arbotom to determine the degree of swelling inside the tree. Based on this, we tried to present data that can be referred to when surgical operation of trees is required. In order to acquire a tomographic image of a tree, 6 sensors were attached to the three Yangpala and Maple trees, and a 1 m-long tree was measured using the Arbotom program, and a 3D image was implemented through the 3D Viewer created using MATLAB. In addition to simply acquiring images, the cross-sectional length and volume of the tree were measured. In the actually produced 3D Viewer, the length of the part where the swelling of the maple tree occurred was 33.12 cm, and the swelling of the yangpala tree was measured as 21.41 cm. The volume of the maple tree was measured to be 78.832 ㎤. As a result of comparing the cross-sectional image of the Arbotom and the 3D image, the same result as the real aspect of the tree was obtained, so it can be judged that the reliability of the manufactured software is also secured, and data to be applied to the surgical tree operation through the created Viewer is provided. It is believed that the damage will be minimized.

• Journal of Bio-Environment Control
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• v.30 no.3
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• pp.237-243
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• 2021

The objective of this study was to evaluate the effect of stem number on plant growth, fruit quality, and yield of sweet peppers grown in greenhouses under supplemental lighting in winter. The seedlings were transplanted at 3.2 plants·m^-2 on October 26, 2020, and started supplemental lighting with 32 high pressure sodium lamps for 16-hour photoperiod from December 1, 2020 to May 25, 2021. Stems were differently trained with 2 and 3 numbers after branching nodes were developed. In the final harvest, the plant height was significantly shorter in the 3 stem-plants than in the 2 stem-plants. The number of nodes per stem and the leaves per plant were increased in the 3 stem-plants than in the 2 stem-plants, while the leaf area was less affected. There were no significant differences in the dry mass of leaves, stems, and immature fruits between the 2 and 3 stem-plants. The fruit fresh weight and fruit dry weight in the 3 stem-plants were decreased by 17% and 12% at 156 days after transplanting (DAT), and by 17% and 15% at 198 DAT compared to those in the 2 stem-plants, respectively. The marketable fruit rates were 93.6% and 95.4% in the 2 and 3 stem-plants, respectively. The total fruit yield in the 3 stem-plants was increased by 30.2% as compared to that in the 2 stem-plants. We concluded that the 3-stem-training cultivation positively affected the total fruit yield by sustaining adaptive vegetative growth of the plants. This result will help producers make useful decisions for increasing productivity of sweet peppers in greenhouses.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.1
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• pp.77-94
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• 2021

The purpose of this study was to investigate the three-dimensional characteristics of mesiodens using Cone-beam Computed Tomography(CBCT) and analyze the factors affecting complications and anesthetic methods of extraction. This study evaluated 602 mesiodens of 452 patients who underwent extraction of mesiodens at the department of Pediatric Dentistry in Seoul National University Dental Hospital between 2017 and 2019. The ratio of mesiodens patients over total patient per year was gradually increased over the past 20 years. Mesiodens with labio-palatally horizontal direction while root directing labial were the most common among the mesiodens with horizontal direction. Mesiodens were the most common at the cervical side of the adjacent teeth(37.0%) and mesiodens located in the near-palatal side were observed about 3.83 times higher than the far-palatal side. Most of the mesiodens(82.1%) were in contact with adjacent permanent teeth on all three sides of the CBCT and 46.2% of mesiodens had curved roots. The patient's age, vertical position, presence of complications, and proximity showed a significant difference in the selection of general anesthesia among anesthetic methods. The direction and vertical position of mesiodens had a significant effect on complications. These results provide a better understanding of mesiodens for establishing an accurate diagnosis and treatment plan.

• Journal of Nutrition and Health
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• v.52 no.1
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• pp.47-57
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• 2019

Purpose: This study was conducted to investigate the relationship between atopic dermatitis and dietary fat and fatty acid (FA) intakes in 9 ~ 11 year old children. Methods: We analyzed data from the combined 2013 ~ 2015 KNHANES (Korean National Health and Nutrition Examination Survey). Subjects were divided into two groups according to atopic dermatitis (AD); with AD and without AD. Data pertaining to macronutrients and FA intakes were obtained by a single 24-h dietary recall. Food sources were identified based on the amounts of total fat and FA consumption according to each food. The associations between each FA intake and atopic dermatitis were analyzed using simple and multiple logistic regression analyses. Age, sex, body mass index (BMI) and income levels were adjusted as covariates. Results: Of the participants, 17.69% suffered from atopic dermatitis. Children with AD had significantly lower fat percentages of total energy and higher carbohydrate percentages of total energy than normal children. Percentages of energy and intakes of polyunsaturated fatty acid (PUFA), n-3 FA and n-6 FA in children with AD were significantly lower than those in normal children. In the FA, linoleic acid, ${\gamma}$-linoleic acid and ${\alpha}$-linolenic acid levels of children with AD were significantly lower than those of normal children. However, the P/S ratio and n-6/n-3 ratio did not differ significantly between children with AD and normal children. Soybean oil was the main contributor to PUFA, n-3 FA and n-6 FA in both groups, while perilla seed oil and mackerel were the major food sources of n-3 FA in children with atopic dermatitis. Atopic dermatitis was significantly correlated with low-fat and high-carbohydrate diets. The adjusted odds ratios were 0.966, 0.776 and 0.963 for PUFA, n-3 FA, and n-6 FA intakes, respectively. Conclusion: The present study provides reliable evidence regarding the relationship between fat and FA intakes and AD in Korean children 9 ~ 11 years of age.

• Korean Journal of Heritage: History & Science
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• v.50 no.3
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• pp.64-87
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• 2017

Dahoe is a traditional braid in Joseon Dynasty. There are many Dahoe artifacts, which can give us a glimpse of the costume, culture, and life of that era. The study of Dahoe is necessary in various fields, but it is difficult because this manufacturing technique has been passed down from hand to hand. Few studies have been done so far. This research examines the manufacturing technique of KwangDahoe which is passed down by Maedeupjang (Decorative Knotting) and is generally used for knotting and/or tying objects. The main characteristic of TieKwangDahoe, made through the same method as WonDahoe, is the square hole in the middle. It was impossibile to remake the original braid because there is no confirmed number of the strand. Especially it is very difficult to do conservation and restoration on serious degradation state of the fiber. Therefore, it is necessary to analyze the non-destructive manufacturing techniques method for Dahoe and assess their applicability. First, we analyzed the artifacts' manufacturing technique based on the database of the Dahoe's manufacturing technique. In order to do that, we undertook schematization, restoration, morphological analyzation of the Dahoe. And then, X-ray CT scans were performed to improve the reliability of the DB. These results of scanning were interpreted based on the manufacturing technique. The selected Tie-KwangDahoe on the sword for the study are artifacts including artistic value and symbolism in Joseon Dynasty. Based on the analysis of the manufacturing technique, we found that both artifacts were made of 20-strand braid of single cross according to the length-scale measure. It was manufactured using 8-strand on left-right side, 12-strand on front-back side by the braiding manufacturing technique method Finally, this research suggests non-destructive analysis method of Dahoe's manufacturing technique is based on the database and the analysis results. I hope this research can be useful in various professional fields of Dahoe in the future. Moreover, I hope this can be of any help in preserving Korean cultural heritage.

• Korean Journal of Heritage: History & Science
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• v.51 no.4
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• pp.120-145
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• 2018

This study intended to examine the drainage facility of Gyeongbokgung Palace based on the traces of the relic found during the excavation survey. Historical records indicate that various efforts have been made for smooth drainage facility for the palace since the foundation of the Joseon Dynasty. Although there are no drawings showing the image of early appearance of Gyeongbokgung Palace during the foundation, it is possible to estimate it through the drawings prepared after the King Yeongjo's reign. The image of the palace after reconstruction can be seen through the "Bukgwoldohyeong" and other relevant documents. At this present, since the survey intends to determine the image of Gyeongbokgung Palace during the reign of King Gojong based on the standard restoration plan of the Cultural Heritage Administration, this study also focused on the drainage facility of Gyeongbokgung Palace during King Gojong's reign, particularly on the collecting wells and culverts of six areas including "Chimjeon Hall", "Taewonjeon Hall", "Geoncheongung Hall", "Sojubang Hall", "Hamhwadang - Jipgyeongdang - Yeonghundang Hall", and "Heungbokjeon Hall". Gyeongbokgung Palace is divided into various zones composed of the central halls and surrounding corridors, and the drains also primarily start from each hall and later join the central drain of the zone. The central drain then leads to the "Eo-gu(御溝)" and the water led to the "Eo-gu" is finally discharged through the water gate. It appears that this series of processes were basically devised to coordinate artificial drain with the natural drain using the natural geographical features of the palace. Research showed that the collecting well where the draining begin was installed in the area where a large amount of household sewage was generated but mostly in the corners where corridors met or corridors and wall met. This appears to be an arrangement to handle the water falling from the roof and household sewage. Also, "Ju(廚)" was installed mainly at the end of the corridor to handle household sewage. The installation of these drainage facilities shows the possibility that the drainage of Gyeongbokgung was very compact under a series of plans.

• Journal of the Society of Disaster Information
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• v.15 no.2
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• pp.249-258
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• 2019

Purpose: The purpose of this study is to attain the correlation analysis and thereby to deduce the uniaxial compressive strength of rock specimens through the elastic wave velocity and the elastic modulus among the physical characteristics measured from the rock specimens collected during drilling investigations in Seoul and Gyeonggi region. Method: Experiments were conducted in the laboratory with 119 granite specimens in order to derive the correlation between the compressive strength of the rocks and elastic wave velocity and elastic modulus. Results: In the case of granite, the results of the analysis of the interaction between the compressive strength of a rock and the elastic wave velocity and elastic modulus were found to be less reliable in the relation equation as a whole. And it is believed that the estimation of the compressive strength by the elastic wave velocity and elastic modulus is less used because of the composition of non-homogeneous particles of granite. Conclusion: In this study, the analysis of correlation between the compressive strength of a rock and the elastic wave velocity and elastic modulus was performed with simple regression analysis and multiple regression analysis. The coefficient determination ($R^2$) of simple regression analysis was shown between 0.61 and 0.67. Multiple regression analysis was 0.71. Thus, using multiple regression analysis when estimating compressive strength can increase the reliability of the correlation. Also, in the future, a variety of statistical analysis techniques such as recovery analysis, and artificial neural network analysis, and big data analysis can lead to more reliable results when estimating the compressive sterength of a rock based on the elastic wave velocity and elastic modulus.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.2
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• pp.89-96
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• 2019

This study was conducted to investigate 106 grassland farms in six provinces including Chungcheongbuk-do, Gangwon-do, Gyeonggi-do, Gyeongsangbuk-do, Gyeongsangnam-do, Jeju-do, and Jeollanam-do to present their problems and causes by surveying the actual state of grassland farms during three years(2014~2016). The grassland survey was divided into three categories; used as the perennial grasses and annual forage crops (Complied with Grassland Act), not used as the perennial grasses and annual forage crops (Not complied with Grassland Act) and failed to meet the farmer and some items are missing or inaccurate (Insufficient contents). Among the surveyed grassland farm, 68 farms (64.2 %) were complied with Grassland Act but 30 farms (28.3 %) were not complied with Grassland Act. Especially, the 8 farms (26.7 %) not complied with Grassland Act used the grassland as other purposes such as tree growing, golf club and swine farm etc.. Therefore, strict on-site investigation by local governments is required to prevent the grassland from being used by illegal purposes. And there's a strong likelihood that 5 farms (62.5 %) avoided the survey violate the positive law. Grassland grades used by the local administrative agencies were not influenced by the factors affecting the yield (existence and non-existence of overseeding and fertilization by grassland grade, soil pH and organic matter content). This results suggest that there is a fundamental problem on the current grassland grade system based on the yield and the irregular time of investigation and lack of on-site investigation are another causes for inaccurate grassland grade. Therefore, the new method evaluating grassland grades which is not based on yield and the thorough on-site investigation by local administrative agencies are necessary when the grassland grade is evaluated.