• Journal of the Korean association of regional geographers
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• v.4 no.1
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• pp.43-56
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• 1998

The purpose of this study is to identify distributional characteristics of climatic elements and to analyze synoptic characteristics on the pressure fields for spring droughts in Korea. In the distributions of minimum temperature during the spring droughts, positive anomalies and negative anomalies are mixed up, but in March the negative anomaly areas are widely distributed in Korea. It implies that the droughts of March have more frequent occurrences of the west-high, east-low pressure patterns. In the maximum air temperatures, the positive anomalies appear in Korea. It indicates that the spring droughts have rain days, cloud amount and humidities less than normal. As a result, the amount of evaporation is increased in Korea. In the pressure anomaly of surface pressure fields, the positive anomalies appear in the west, negative anomalies in the east in March, but in May the positive anomalies appeared zonally around the Korean peninsula. It indicates that March droughts have more frequent occurrences of the west-high. east-low patterns, but in May the Korean Peninsula has more frequent recurrences of the migratory anticyclone patterns. The height anomaly patterns of 500hPa pressure surface in spring droughts are similarly shown to those of surface fields. In March droughts, the positive height anomalies appear in the west, the negative height anomalies in the east, but in April the negative height anomaly areas are extended to the west part. In May the positive anomalies appear zonally around the Korean Peninsula, and strong positive height anomalies appear around the Kamchatka Peninsula and the sea of Okhotsk. These are the result of circulations that inhibit the eastward movement of westerlies and that has persistent anticyclone circulation patterns around the Korean Peninsula. As a result, the zonal indices of westerlies during March and April droughts are lower than normal, but higher in May. These data indicate that early spring droughts are associated with weak zonal flow, but the late spring droughts are obviously related with strong zonal flow. In addition, during early spring droughts the abnormally deep trough over the west coast of the North Pacific Ocean that accompanied the anticyclone was associated with frequent advection of air from the dry regions in the Central Asia into the Korean Peninsula. The atmospheric circulation patterns at the height of the 500hPa pressure surface in May was quite different from March and April circulation patterns. Instead of the abnormal ridge in the west and trough in the east, the circulation pattern in May was characterized by a much stronger than normal anticyclone over the Korean Peninsula. Also, the zonal indices of westerlies in May are higher than normal. The occurrences of drought in early spring, therefore, have mechanism different from those of late spring.

• Restorative Dentistry and Endodontics
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• v.34 no.5
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• pp.424-429
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• 2009

This study aimed to assess the influence of different cross-sectional area on the cyclic fatigue fracture of Ni-Ti rotary files using a fatigue tester incorporating cyclical axial movement. Six brands of Ni-Ti rotary files (ISO 30 size with. 04 taper) of 10 each were tested: Alpha system (KOMET), HeroShaper (MicroMega), K3 (SybronEndo), Mtwo (VDW), NRT (Mani), and ProFile (Dentsply). A fatigue-tester (Denbotix) was designed to allow cyclic tension and compressive stress on the tip of the instrument. Each file was mounted on a torque controlled motor (Aseptico) using a 1:20 reduction contra-angle and was rotated at 300 rpm with a continuous, 6 mm axial oscillating motion inside an artificial steel canal. The canal had a $60^{\circ}$ angle and a 5 mm radius of curvature. Instrument fracture was visually detected and the time until fracture was recorded by a digital stop watch. The data were analyzed statistically. Fractographic analysis of all fractured surfaces was performed to determine the fracture modes using a scanning electron microscope. Cross-sectional area at 3 mm from the tip of 3 unused Ni-Ti instruments for each group was calculated using Image-Pro Plus (Imagej 1.34n, NIH). Results showed that NRT and ProFile had significantly longer time to fracture compared to the other groups (p < .05). The cross-sectional area was not significantly associated with fatigue resistance. Fractographycally, all fractured surfaces demonstrated a combination of ductile and brittle fracture. In conclusion, there was no significant relationship between fatigue resistance and the cross-sectional area of Ni-Ti instruments under experimental conditions.

• Korean Journal of Heritage: History & Science
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• v.53 no.2
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• pp.110-139
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• 2020

Reclamation is the act of creating new lands by constructing dikes in offshore tidal flats to utilize them for various purposes, including the establishment of farmland to secure food for an increasing population. Based on the fact that reclamation has resulted in drastic changes in the environmental, economic, social, and cultural aspects of land expansion and development, population movement, and the formation of cities since ancient times, I reviewed the value of reclamation sites and addressed the issue of how to preserve and utilize them. "Reclamation culture" refers collectively to the recognition and concept system, behavior styles, and cultural products created by changes in the environment, and the tangible, intangible, and natural heritage generated directly and indirectly by reclamation is defined as "reclamation cultural heritage". It shows that the historical background of reclamation accords with prevailing trends, and that the reclamation sites possess cultural heritage value due to their historical, academic, and scarce characteristics. Numerous reclamation cultural heritage sites at the Gwangwhal and Gyehwa dikes are on the verge of being destroyed, with their original function having ended after the construction of Saemangeum Sea Wall. I propose measures to preserve these under the principle that utilization is based on the basic premise of conservation. First of all, modern and contemporary reclamation sites must necessarily be designated and managed as registered cultural properties, local cultural heritage, future heritage, and agricultural heritage. In particular, as it has been confirmed that reclamation sites created after the Goryeo and Joseon dynasties and the 1950s have not been designated as cultural heritage sites. It is necessary to review the characteristics and values of such reclamation sites through a full survey of national reclamation data. Effective and sustainable utilization of reclamation cultural heritage, which has not been acknowledged in the past due to its close relationship with our lives, is necessary to search for hidden stories found within that heritage, to organize governance for the efficient use of reclamation resources, and to build a museum to collect and display the history and culture of the reclaimed areas. Finally, through links with countries with experience in reclamation, we will be able to cope jointly with international issues such as those pertaining to society, culture, and environment, and would be able to implement various projects to further the advancement of human beings.

• Korea journal of population studies
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• v.11 no.1
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• pp.50-57
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• 1988

This study focused on the anding of Inchon's identity The empirical method and ethnomethodological approaches were used to collect the data. Among members ofcitizen movement groups,government workers,and students who are living inInchon were selected as 613 samples using a purposive sampling method. MultipleClassification Analysis (MCA) and cross-tabulation methods were used in theanalysisThe study of identity in an area is important in terms of providing the solution ofthe problem in a region and social integration of the citizens. The scores of the indexabout Inchon's identity are quite low and more than half of the respondents to allthree groups showed the middle position of the scores from the identity index. By thecharacteristics of the respondents,female,unmarried single,30 years or more,lowerincome groups showed relatively higher identity index scores than other counter-parts . And professional,administrative,clerical workers'identity index scores werehigher than people who work at sales,service,and agricultural sectors. Respondentswith 2 years of college or more,with intentions to donate special monies for cultural, social welfare, environmental reform,persons who want to live in Inchon for along period of time equipped with a stronger identity index.For the character of Inchon's identity,there are no identity,making it fromnow on,capacity or broad-minded city,vanguard pioneer,displeased, Oiversity/multiplicity of the city,defense spirit from foreign invasion,entrancecity from the world in that order. Therefore,it is hard to say what exactly Inchon'simage is in a single word. However,Inchon can be characterized as a diverse citywith capacity to live together without any serious conflicts among citizens who come from Seoul,Kyunggi-Do,Chungchung-Do,Chunla-Do,Kyungsang-Do,and foreign countries including North Korea. These facts imply that Inchon should continue topursue this image as a diverse city with capacity as an identity pursuing towardsworld city and hub city of North East Asia.ty as an identity pursuing towardsworld city and hub city of North East Asia. East Asia.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.594-604
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• 2021

To evaluate the causes of beach erosion in Sinji-Myeongsasimni Beach, external forces, such as tides, tidal currents, and waves, were observed seasonally from March 2019 to March 2020, and the surface sediments were analyzed for this period. In addition, the shoreline positions and beach elevations were regularly surveyed with a VRS GPS and fixed-wing drone. From these field data, the speed of the tidal currents was noted to be insufficient, but the waves were observed to af ect the deformation of the beach. As the beach is open to the southern direction, waves of heights over 1 m were received in the S-SE direction during the spring, summer, and fall seasons. Large waves with heights over 2 m were observed during typhoons in summer and fall. Because of the absence of typhoons for the previous two years from July 2018, the beach area over datum level (DL) as of July 2018 was greater by 30,138m² compared with that of March 2019, and the beach area as of March 2020 decreased by 61,210m² compared with that of March 2019 because of four typhoon attacks after July 2018. The beach volume as of March 2019 decreased by 5.4% compared with that of July 2018 owing to two typhoons, and the beach volume as of September 2019 decreased by 7.3% because of two typhoons during the observation year. However, the volume recovered slightly by about 3% during fall and winter, when there were no high waves. According to the sediment transport vectors by GSTA, the sediments were weakly influxed from small streams located at the center of the beach; the movement vectors were not noticeable at the west beach site, but the westward sediment transport under the water and seaward vectors from the foreshore beach were prominently observed at the east beach site. These patterns of westward sediment vectors could be explained by the angle between the annual mean incident wave direction and beach opening direction. This angle was inclined 24° counterclockwise with the west-east direction. Therefore, the westward wave-induced currents developed strongly during the large-wave seasons. Hence, the sand content is high in the west-side beach but the east-side beach has been eroded seriously, where the pebbles are exposed and sand dune has decreased because of the lack of sand sources except for the soiled dunes. Therefore, it is proposed that efforts for creating new sediment sources, such as beach nourishment and reducing wave heights via submerged breakwaters, be undertaken for the eastside of the beach.

• Journal of Wetlands Research
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• v.23 no.4
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• pp.317-326
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• 2021

The present study was carried out with a view to understand the distribution and ecology of Clihton retropictus (Martens, 1879), a class II endangered wildlife designated and protected by the Ministry of Environment, Republic of Korea, and to suggest the effective conservation and management measures for this species and its habit. First, the distribution of Clihton retropictus was investigated nationwide, and environmental factors such as salinity and substratum were analyzed in consideration of the ecological characteristics of this species. In addition, the individual size, density, and movement of Clihton retropictus per each district surveyed were analyzed. Due to its nature of inhabiting in the brackish water zone, the analysis showed that the salinity of this species was 0.7 ~ 16.6‰ at low tide and 1.0 ~ 17.3% at high tide. It was learned from the analysis of substratum that its composition in each river under investigation was slightly different, but most of substratum had a higher composition ratio than gravel (pebble, 16 ~ 64 mm). On the other hand, the size of each individual was checked by measuring the length of its diameter, and there was almost no change in the individual when the inhabited range of Clihton retropictus was short. However, there was tendency that the longer the habitat range, the bigger the individual size. From surveying the population density by season, it was made clear that, during the summer (July to August) and fall (September to October), the density was relatively higher while the number of individuals decreased significantly during winter (November to December) when the water temperature was lowered. In an effort to effectively establish conservation and management measures, the moving distance was measured, and it became known that, during the surveys in summer and fall when the individuals were active, the individuals moved in more distances than during the winter survey. The results of this study are expected to be utilized as basic data for establishing effective management plans such as creation of habitats for Clihton retropictus, its migration projects and selection of migration destinations which get unavoidable due to development projects.

• Journal of Life Science
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• v.31 no.9
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• pp.787-795
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• 2021

Eupatorium chinensis var. simplicifolium (EUC) has anti-inflammatory and antioxidant effects. Young sprouts of EUC have been used as food for a long time, and the whole EUC plant has been used as an herbal remedy in oriental medicine. Arteriosclerosis, or chronic inflammation in arterial vessels, is a cardiovascular disease and is involved in various disorders. Cardiovascular diseases such as restenosis and neuropathic hyperplasia are mainly caused by abnormal growth and movement due to multiple growth factors in vascular smooth muscle cells (VSMCs). Platelet-derived growth factor (PDGF) is a mitogen released from damaged vessel walls and is involved in the proliferation and migration of VSMCs. To determine the effects of EUC on the abnormal proliferation and migration of VSMCs, the present study investigated intracellular signaling pathways in PDGF-BB-induced VSMCs treated with and without EUC. Pretreating PDGF-BB-induced VSMCs with EUC tended to effectively decrease cell proliferation and migration. Subsequently, the intracellular growth-related signaling pathways of AKT, phospholipase C gamma (PLC-γ), and mitogen-activated protein kinase (MAPK) were investigated using western blotting to confirm inhibited phosphorylation. Furthermore, flow cytometry data showed that EUC blocked the cell cycle of VSMCs. These results suggest that EUC can inhibit the proliferation and migration of VSMCs by controlling the cell cycle and growth factor receptors. Furthermore, this indicates that EUC can be used as a preventative against cardiovascular disease resulting from abnormal proliferation and migration of VSMCs.

• Korean Journal of Plant Taxonomy
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• v.51 no.3
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• pp.250-293
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• 2021

Limestone areas are sedimentary rock outcrops consisting of calcium carbonate created several hundreds of millions of years ago by calcium-secreting marine organisms and subsequently lifted above sea level by tectonic movement. Limestone areas support very high levels of endemic species of plants and are recognized as biodiversity areas with much biological information. The purpose of this study is to devise a strategy for the comprehensive conservation of the vegetation of limestone areas through analyses of the floristics and plant species compositions in ten limestone areas on the Korean Peninsula. The results of 153 field surveys from April of 2010 to October of 2016 identified 1,202 taxa in total, representing 1,096 species, 18 subspecies, 84 varieties, 2 forms, and 2 hybrids in 530 genera and 133 families. Among them, 55 taxa were endemic plants to Korea, and 38 taxa were red data plants. The floristic target plants amounted to 102 taxa, specifically 27 taxa of grade V and 75 taxa of grade IV. In all, 121 alien plants were recorded in the investigated area. Calciphilous plants amounted to 102 taxa, specifically 14 taxa of calciphilous indicator plants, 30 taxa of superlative most calciphilous plants, and 58 taxa of comparative more calciphilous plants. A cluster analysis showed a high degree of similarity between sites that are geographically adjacent with similar habitat environments. Limestone areas also supported groups distinct from those in non-limestone areas, demonstrating the specificity of limestone flora. Plant geography approaches therefore appear to be crucial to gain a better understanding of the level of biodiversity in limestone areas, not only at the interspecific but also at the intraspecific level. These results highlight the importance of protecting limestone habitats to preserve not only their interspecific but also the intraspecific diversity, which is highly threatened.

• Korean Journal of Heritage: History & Science
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• v.47 no.3
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• pp.42-59
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• 2014

Han Pilgyo (1807~1878) was a scholar-official in the later period of the Joseon Dynasty. The research results on spatial structure and landscape techniques of the central government office reviewed through the Sukcheonjeado(宿踐諸衙圖) album collection edited by Han Pilgyo are as follows. First, Sukcheonjeado(宿踐諸衙圖) using Sabangjeondomyobeob(四方顚倒描法, a Korean traditional drawing type) is uniquely proven historical data which helps to understand the spatial structure of the center and local government offices and the characteristics of cultural landscape. Secondly, the central government office located in Yookcho(六曹) Street which is the outside Gwanghwamun(光化門) of the Main Palace(Gyeongbokgung, 景福宮) of the Joseon Dynasty has a center facility(Dangsangdaecheong, 堂上大廳) and attached buildings which are distributed from high to low or from left to right, according to its order of presidency in square-shaped portion of land. The main building was located facing south and by considering the administrative convenience, the environmental effect and the practice of Confucian norms this structure reflects a hierarchical landuse system. Thirdly, the main buildings such as Dangsangdaecheong and Hyangcheong(鄕廳), which are the working place for government officials had large square front yards for constructing a practical patio garden. The back garden was tended to reflect the meaning landscape, with such as pond and pavilion. A particular point was the repeated crossing of active space and passive space(movement and stillness, building and yard, yard and garden), which implements the Yin-Yang principle. Fourth, the characteristics that can be extracted from the central government office landscapes are (1) expandability of outdoor space, connects of front gardens, emphasizes the characteristic of serviceable gardens and back gardens, which in turn emphasizes scenic sides, (2) introduction of water features(square-shaped ponds) that can be used as fire-water and considers environmental-amenity and landscape characteristics, (3) introduction of pavilions for relaxation, mental and physical discipline, and the development of back gardens, (4) significance of Jeongsimsoo(庭心樹) in such things as selection of concise landscape plants like lotus, willow, pine, zelkova and so on, and limited plant introduction, (5) environmental design techniques which set importance on not only aesthetics and ideality but also practical value. Thus, these aspects of the government office landscape can be said to be the universality and particularity of Korean traditional landscape technique and can be extracted similarly in the palaces, temples, lecture halls, and houses of the upper class of the Joseon Dynasty.

• The Korean Journal of Air & Space Law and Policy
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• v.34 no.1
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• pp.159-201
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• 2019

Along with Annex 14 Volume I establishment in 1951 and the set-up of restriction surface around the runway, aeronautical technique and navigation performance achieved dazzling growth, and the safety and precision of navigation greatly improved. However, restrictions on surrounding obstacles are still valid for safe operation of an aircraft. Standards and criteria for securing safety of aircraft operating around and on airport is stated in Annex 11 Air Traffic Services and Annex 14 Aerodrome etc. In particular, Annex 14 Volume I presents the criteria for limiting obstacles around an airport, such as natural obstacles such as trees, mountains and hills to prevent collisions between aircraft and ground obstacles, and artificial obstacles such as buildings and structures. On the other hand, Annex 14 Volume I, in the application of the obstacles limitation surfaces, apply the exception criteria, as it may not be possible to remove obstacles that violate the criteria if the aeronautical study determines that they do not impair the safety and regularity of aircraft operation. Aeronautical study has been applied and implemented in various countries including United States, Canada and Europe etc. accordingly, Korea established and amended some provisions of the Enforcement rules of the Aviation Act and established the Aeronautical study guidelines to approve exceptions. However, because ICAO does not provide specific guidelines on procedures and methods of Aeronautical study, countries conducting aeronautical study have established and applied their own procedures and methods. Reflecting this realistic situation, at the 12th World Navigation Conference and at the 38th General Assembly, the contracting States demanded a reexamination of the criteria for current obstacle limitation surfaces and methods of aeronautical study, and the ICAO dedicated a team of experts to prepare new standard. This study, in line with the movement of international change in obstacle limitation surface and aeronautical study, aims to compare and analyze current domestic and external standards on obstacle limitation and height limits, while looking at methods, procedure and systems for aeronautical study. In addition, expecting that aeronautical study will be used realistically and universally in assessing the impact of obstacles, we would recommend the institutional improvement of the aeronautical study along with the development of quantitative analysis methods using the navigation data in the current aeronautical study.