• Journal of Korean Society of Forest Science
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• v.107 no.4
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• pp.385-392
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• 2018

The slope stabilization analysis was performed by conducting survey and selecting the representative section in order to improve slope composition and management technology of masonry embankments in the quarry area, The mean slope of the masonry retain wall (A, B, C, D, E, F) was $38.5^{\circ}$, although the steep slope of the lowest slope (A) as $59^{\circ}$. The horizontal distance of the masonry embankments is 66.2 m and the slope height is 48.3 m. However, the inclination of the masonry embankments is relatively steep and visually unstable. The slope stability analysis for the slope stability analysis was taken into account during the drying and saturation. The slope stability analysis during saturation was performed by modeling the fully saturated slope. The strength constants of the ground were divided into two groups. The safety factor for dry period was 1.850 and the safety factor for rainy season was 1.333. The safety rate of dry period and rainy season was above 1.5 and 1.2. However, the weathered granite on the upper part of the masonry embankments at the time of heavy rainfall is considered to have a high risk of slope erosion and collapse. Therefore, it is considered necessary to take measures for stabilization through appropriate maintenance such as drainage installation.

• Journal of Korean Society of Forest Science
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• v.108 no.3
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• pp.311-321
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• 2019

This study was carried out to establish basic data for the development of slow-moving landslide hazard classes. Mountain slopes in slow-moving landslide areas ranged from $11.8^{\circ}$ to $37.0^{\circ}$ with a mean slope of $23.8^{\circ}$. However, the slope inclination of microtopography in slow-moving landslide areas was slightly different, with a mean slope of $23.5^{\circ}$ ($10.7^{\circ}{\sim}41.5^{\circ}$) compared with the mountain slope. There was a significant difference (p < 0.05) between the contour intervals of microtopography and the contour intervals of the slow-moving landslide areas. Among all the slow-moving landslide areas examined, 14 plots (approximately 38.0%) were classified into landslide hazard class I, 6 plots (approximately 16.0%) into landslide hazard class II, 5 plots (approximately 14.0%) into landslide hazard class III and IV, and 16 plots (approximately 43.0%) into landslide hazard class V, whereas 9 plots (approximately 24.0%) fit the no landslide hazard class.

• Korean journal of applied entomology
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• v.58 no.2
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• pp.143-149
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• 2019

This study was conducted to examine the attractiveness of yellow sticky trap (YST) for insect pests by the angle of inclination of the trap surface. In strawberry farms with high bed system, YSTs were installed to attract insect pests in vertical direction with one surface, horizontal direction with upper and under surface, and angle of $45^{\circ}$ with upper and lower sticky surface. Thrips (Frankliniella occidentalis in dominance) and Sciaridae (Bradysia agrestis in dominance) species were more attracted on upper surface of $45^{\circ}$ angle trap, vertical surface and upper surface of horizontal trap than on lower surface of $45^{\circ}$ angle trap or horizontal trap. Cicadellidae (Empoasca vitis in dominance) species were caught more on vertical surface and upper surface of $45^{\circ}$ angle trap than on other traps. There were no specific trend in capture of aphid (Aphis gossypii in dominance) and white fly (Trialeurodes packardi in dominance) species among traps, probably because of a low density of the pest species.

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.449-454
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• 2011

This experiment was conducted to evaluate growth rate among 15 embryogenic tissue lines (ETLs), comparison of maturation on somatic embryos (SEs) with 13 ETLs and efficiency with various concentrations of gelrite on SEs germination in Japanese red pine (Pinus densiflora). In comparison of ETLs growth rate (folds) with 15 lines, the 05-4 line (5.3 folds) showed the highest rate, on the other hand, the lowest one was recorded in the line of 05-37 (1.4 folds). The 13 ETLs were tested for the extent of SEs production. The best production was recorded in the line of 05-4 (39.8/90 mg F.W.). However, most of ETLs, except 5 lines (05-4, 12, 21, 29 and 37), did not produce SEs at all, therefore, big differences in the ability of SEs production existed among the ETLs tested. Effects of various gelrite concentrations for SEs germination with 3 ETLs were also compared. The highest result was obtained from 0.2% gelrite concentration with 05-4 line (47.3%), there was a inclination that the rate of germination was gradually declined over 0.2% gelrite concentration with the 05-4 and 29 lines. respectively. In contrast, in the line of 05-37, no SEs germination occurred on medium with 0.1 or 0.2% gelrite. In conclusion, the growth rate, SEs production and germination frequency were appeared to deeply depended on the ETLs.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.2
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• pp.202-210
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• 2022

Recently with the advance in digital dentistry, the fabrication of dentures using computer-aided design and computer-aided manufacturing (CAD-CAM) is on the rise. The denture designed through a CAD software can be produced in a 3-dimensional manufacturing process. This process includes a subtractive processing method such as milling and an additive processing method such as 3D printing and in which it can be applied efficiently in more complex structures. In this case, complete dentures were fabricated using Stereolithography (SLA)-based 3D printing to shorten the production time and interval of visits in patient with physical disabilities due to cerebral infarction. For definitive impression, the existing interim denture was digitally replicated and used as an individual tray. The definitive impression obtained with polyvinyl siloxane impression material was including information about the inclination and length of the maxillary anterior teeth, vertical dimension, and centric relation. In addition, facial scan data with interim denture was obtained so that it can be used as a reference in determination of the occlusal plane and in arrangement of artificial teeth during laboratory work. Artificial teeth were arranged through a CAD program, and a gingival festooning was performed. The definitive dentures were printed by SLA-based 3D printer using a FDA-approved liquid photocurable resin. The denture showed adequate retention, support, and stability, and results were satisfied functionally and aesthetically.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.3
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• pp.203-214
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• 2022

As the global demand for small satellites weighing less than 500 kg increases, the development and operation of dedicated small launch vehicles increase significantly. The responsiveness of a launch vehicle that puts a small satellite into a target orbit at the desired time is attracting attention. As a result, interest in the air launch is increasing in the rapid establishment of a constellation. As the demand for small satellites in south Korea increases, this study performed analyses on the applicability of an air launch vehicle using a large civil aircraft considering the geographical environment. In terms of responsiveness, mission response times were compared and analyzed for air launch vehicles and ground small and large vehicles. In addition, an air vehicle and a small ground vehicle were quantitatively compared and analyzed for the orbital insertion performance. As a result of the analysis, the air launch vehicle has limited responsiveness in Korea regarding rapid satellite constellation establishment. However, it can be an effective alternative for low inclination angle orbit insertion with the benefit of a fast turnaround time. Furthermore, the performance of the orbital injection is close to that of the ground small launch vehicle, and the high efficiency in terms of the required propellant mass is possible, so air launch can be an effective launch means for putting small satellites into orbit in Korea.

• Journal of the Korean Society of Earth Science Education
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• v.15 no.2
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• pp.249-262
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• 2022

This study was conducted on the alternative concept of elementary school pre-service teachers to seasonal changes. From May 2021 to June 2022, it was conducted with 60 pre-primary teachers at P National University of Education. The conclusion of this study is as follows. First, pre-primary teachers explained the cause of seasonal changes, and out of 60 pre-primary teachers, only 22 (36%) had scientific concepts, and the remaining 38 (64%) students had alternative concepts. Second, in explaining how the inclination of the Earth's axis of rotation is related to seasonal changes, only 16 (27%) of the 60 pre-primary teachers had a scientific concept, and the remaining 44 (73%) had alternative concepts. Third, pre-primary teachers explained the relationship between the change in the solar altitude and the seasonal change. Among 60 pre-primary teachers, 12 (20%) had a scientific concept, and the remaining 48 (80%) had alternative concepts. Fourth, looking at the comprehensive types of alternative concepts for seasonal changes, the aS-bS-cS type, which is classified as a type that explains the causes of seasonal changes using scientific concepts as a whole, was 8(13%) out of 60 pre-primary teachers. and the remaining 52 (87%) had at least one alternative concept to explain seasonal changes.

• The Journal of Korean Philosophical History
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• no.27
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• pp.145-166
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• 2009

This paper analyzes the views of Gyeongjae O Chiik on Classical Studies. O is the second son of Noju O Heesang (1763-1833). The characteristics of his views are as follows. First, unlike his father, Gyeongjae is more interested in Chinese Textual Criticism than in Hsing-li hsüeh. Therefore, he provides textual interpretation in detail with erudition in his Manrok and Munjip on the formation and problems for such classics as The Four Classics, The Classic of Poetry, The Book of Changes, The Rites of Zhou, The Book of Rites, and The Spring and Autumn Annals. Second, his openness. He didn't canonize The Book of Changes. Also, he thought that the analysis of Jeongja in his Annotation on the Book of Changes and Zhuxi's Original Interpretations, the absolute authority of the time, were not the only interpretation possible. He argued that other interpretation is possible depending on perspectives and it is desirable. We can see that Gyeongjae had transcended the world view of Zhuxi Studies. Third. he put the emphasis on the theories during the Han dynasty. He showed the inclination toward the Yuheung theories rather than Zhuxi theories in regard of the discussion of names in The Analects of Confucius. Fourth, unlike other Confucius scholars in Chosun, he showed interests in Gongyangjeon and Gokryangjeon. He compiled Gonggokmunseon with beautiful writings from both works. Fifth, he was interested in the dynamics of constant numbers. He grasped that what is important in the Book of Changes is not right principles but constant numbers and points. Thus he compiled Sangjeomyuhoe. Besides, he was also interested in the Rites of Zhou.

• Journal of the Korean Geotechnical Society
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• v.23 no.6
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• pp.97-102
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• 2007

Though the stability analysis of soil slopes widely employs the limit equilibrium method, the study on the jointed rock slopes must consider the direction of joint and the characteristics of Joint at the same time. This study analyzes the result of the change in the factors which show the characteristics of discontinuity and the shape factor of rock slopes, and so on, in an attempt to validate the propriety as to the interpretation of jointed rock slope stability which uses the general finite element program. First, the difference depending on the flow rules was compared, and the factor effect study was conducted. The selected independent variables included the direction of joint which displays the mechanical characteristics of discontinuity, adhesive cohesion, friction angle, the inclination and height of rock slope which reveal the shape of slope and surcharge load. And the horizontal displacement was numerically interpreted at the 1/3 point below the slope, a dependent variable, to compare the relative degree of factor effects. The findings of study on factor effects led to the validation that the result of horizontal displacement for each factor satisfied various engineering characteristics, making it possible to be applied to stability interpretation of jointed rock slope. A modelling is possible, which considers the application of the result of real geotechnical surveys & laboratory studies and the non-linear characteristics when designing the rock slope. In addition, the stress change which may result from the natural disaster, such as precipitation, and the construction, can be expressed. Furthermore, as the complicated rock condition and the ground supporting effect can be considered through FEM, it is considered to be very useful in making an engineering decision on the cut-slope, reinforcement and so on.

• Journal of the Korean Geotechnical Society
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• v.23 no.11
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• pp.67-76
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• 2007

The characteristics of rockfall are determined by virtually all factors and conditions e.g. the physical figure of the slope such as inclination, height, roughness, the elemental figure of the slope such as vegetation and material deposited, and the shape and weight of the rockfall itself. Although it is one of the major factors to be considered in rockfall simulation, little attention has been given to the weight of the rockfall. And, since the size of the rockfall is dominated by joint spacing, the distribution of the rockfall block weight can be predicted as a function of the joint spacing. In this study, the weight distribution of rockfall was estimated by using the method of volumetric joint count, $J_{\nu}$, based on joint spacing, and $RQD-J_{\nu}$. The results indicate that the weight distributions were analogous in two methods, and the distribution was to be $75.3{\sim}76.7%$ for 200 kilograms or lesser, $15.0{\sim}16.6%$ for $200{\sim}400$ kilograms, and $6.7{\sim}9.7%$ for 400 kilograms or more, which show good matches with the actual on-site weight distribution. Therefore, the weight distribution of rockfall suggested in this paper is able to be considered as appropriate data for rockfall simulation.