• Journal of the Korean Association of Geographic Information Studies
• /
• v.23 no.3
• /
• pp.12-25
• /
• 2020

The purpose of this study was to obtain information about the type of drones suitable for the management of entrants and entrants of islands in the marine national park. The research sites were 25 islands in the Hallyeohaesang National Park. The target islands were divided into three zones, and were investigated with different types of drones. The survey period was from October to November, 2019. As a result of the operation of drone airframe, drone with fixed wings was found to be favorable for the management of marine parks in medium and long distances compared to other types, but stopping flights for broadcasting was found to be unsuitable. Drone with rotational wings was found to be suitable for image acquisition and broadcasting through close flight. However, it was deemed suitable for short and medium distance flights because of the fast battery consumption. In the case of helicopter rotorcraft drone, image acquisition and broadcasting were possible, but noise and vibration caused by propellers were disadvantageous. The number of entrants to the islands totaled 410 and the main act was fishing. The proportion of entrants to the islands in Area A was higher than that of other areas, and thus it was deemed more necessary to manage the area. Broadcasting was found to have had a positive effect on the management of fishers.

• Korean Journal of Agricultural Science
• /
• v.15 no.1
• /
• pp.27-35
• /
• 1988

In order to elucidate the systematic taxonomy and genetic characters of Canoderma lucidum, cultural characteristics of the fungus were investigated. Mycelial growth of Ganoderma lucidum were favorable on oat meal agar medium, and optimum temperature and pH of the medium for mycelial growth were $30^{\circ}C$ and 5.5-6.0 respectively. Irradiation of white fluorescent lamp inhibited mycelial growth and critical time for inhibition of mycelial growth was 4-8 hours. Concentric zones and mycelial strands of Ganoderma lucidum was induced by irradiation of white fluorescent lamp and formation of mycelial sectors was influenced by nutrient source of media and irradiation of white fluorescent lamp. These characters were different among the isolates, but no relationship was observed between these characters and the fruiting body type of the fungus. Basidiospores were formed directly from the mycelium cultured on artificial media without producing fruit body.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.12
• /
• pp.1071-1086
• /
• 2016

The safety of aircraft can be threatened by environmental factors, such as icing, turbulence, and lightning strike. Due to its adverse effects on aircraft structure and electronic components of aircraft, lightning strike is one of the biggest hazards on aircraft safety. Lightning strike can inject high voltage electric current to the aircraft, which may generate strong magnetic field and extreme hot spots, leading to severe damage of structure or other equipment in aircraft. In this work, mechanism of lightning strike and associated direct and indirect effects of lightning on aircraft were studied. First, on the basis of aircraft lightning regulations provided by Aerospace Recommended Practice (ARP), we considered different lightning waveform and zones of an aircraft. A coupled thermal-electrical computational model of ABAQUS was then used for simulating flow of heat and electric current caused by a lightning strike. A study on fuel tank, with and without lightning protection system, was also conducted using the computational model. Finally, electric current flow on two full scale airframes was analyzed using the EMA3D code.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.19 no.3
• /
• pp.93-101
• /
• 2017

The distribution of inter-annual variation in temperature would help evaluate the likelihood of a climatic risk and assess suitable zones of crops under climate change. In this study, we evaluated two methods to estimate the standard deviation of temperature in the areas where weather information is limited. We calculated the monthly standard deviation of temperature by collecting temperature at 0600 and 1500 local standard time from 10 automated weather stations (AWS). These weather stations were installed in the range of 8 to 1,073m above sea level within a mountainous catchment for 2011-2015. The observed values were compared with estimates, which were calculated using a geospatial correction scheme to derive the site-specific temperature. Those estimates explained 88 and 86% of the temperature variations at 0600 and 1500 LST, respectively. However, it often underestimated the temperatures. In the spring and fall, it tended to had different variance (e.g., increasing or decreasing pattern) from lower to higher elevation with the observed values. A regression analysis was also conducted to quantify the relationship between the standard deviation in temperature and the topography. The regression equation explained a relatively large variation of the monthly standard deviation when lapse-rate corrected temperature, basic topographical variables (e.g., slope, and aspect) and topographical variables related to temperature (e.g., thermal belt, cold air drainage, and brightness index) were used. The coefficient of determination for the regression analysis ranged between 0.46 and 0.98. It was expected that the regression model could account for 70% of the spatial variation of the standard deviation when the monthly standard deviation was predicted by using the minimum-maximum effective range of topographical variables for the area.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.35 no.2 s.121
• /
• pp.71-80
• /
• 2007

Korea began preserving and managing natural monuments in 1933 under Japanese Colonization, but North Korea and South Korea were forced to establish separate natural monument management policies because of the division after the Korean Independence. The purpose of this study is to compare and analyze the natural monument management policies of both south and North Korea between 1933 and 2005 to introduce new policies for Korea unification. The following are the results: First, South Korea manages every type of cultural asset, including natural monuments, through the 'Cultural Heritage Protection Act,' whereas North Korea managing its cultural assets through the 'Cultural Relics Protection Act' and the 'Landmark/Natural Monument Protection Act.' Second, South Korea preserves and utilizes natural monuments for the purpose of promoting the cultural experience of Korean people and contributing to the development of world culture, whereas North Korea uses its natural monuments to promote the superiority of socialism and protect its ruling power. Third, North and South Korea have similar classification systems for animals, plants, and geology, but North Korea classifies geography as one of its natural monuments. Unlike South Korea, North Korea also designates imported animals and plants not only for the preservation and research of genetic resources, but also for their value as economic resources. Fourth, North Korea authorizes the Cabinet to designate and cancel natural monuments, whereas South Korea designates and cancels natural monuments by the Cultural Heritage Administration through the deliberation of a Cultural Heritage Committee. Both Koreas' central administrations establish policies and their local governments carry them out, while their management systems are quite different. In conclusion, it is important to establish specified laws for the conservation of natural heritages and clarified standards of designation in order to improve the preservation and management system and to sustain the diversity of natural preservation. Moreover it is also necessary to discover resources in various fields, designate protection zones, and preserve imported trees. By doing so, we shall improve South Korea's natural monument management policies and ultimately enhance national homogeneity in preparation for the reunification of the Koreas in the future.

• Journal of the Korean Society of Groundwater Environment
• /
• v.4 no.1
• /
• pp.27-40
• /
• 1997

The hydrogeochemical study on the 15 natural waters was carried out in the vicinity of tunnel excavation site of Donghae largely composed of granite and limestone. The water samples can be classified based on their chemical characteristics into two groups; waters draining in the granitic region(group 1) and the limestone region(group 2). This classification was also confirmed by statistical examination through cluster analysis, and the tunnel seepage waters collected at the same site appear to be included in group 1 and 2 by their sampling period, respectively. According to factor analysis, the waters of group 1 art mainly represented by the weathering of plagioclase to kaolinite and those of group 2 are characterized by the dissolution of calcite. Different properties of the tunnel seepage waters are thought to be resulted from the effective waterproofing processes conducted during the sampling interval to the surface and subsurface leakage zones at the granitic region, which contributed to the change of groundwater flow system. However both the tunnel seepage waters seem to have thermodynamically interacted with rock-forming minerals in their wallrocks. The mixing ratio of the waters from two groups and water-rock interactions are evaluated quantitatively for the tunnel seepage waters through the mass balance approach, and the results are identical with the previous conclusions in this study.

• Journal of the Korea Concrete Institute
• /
• v.13 no.6
• /
• pp.568-574
• /
• 2001

From measured responses of concrete three-point bend tests, the average values of the responses have been calculated. The fracture behavior of continuously propagating concrete crack has been analyzed from the average responses. The experimental parameters of this study were the initial notch sizes of 25.4㎜ and 6.4 ㎜ and the processing times of 2,000 sec. and 20 sec . The different notch sizes were used for the effects of the size of fracture process zone and specimen geometry, and the processing times for those of initial creep. However the load-point displacement rate in this study did not affect the experimental responses seriously. The average loads were calculated from the average external work of a series of tests, and average crack lengths were determined by using strain gages. Before the peak load, the resistance curve could be determined from the size of fracture process zone, but unstable crack propagation of 88㎜ occurred at the load-point displacement of 0.088∼0.154㎜ after the peak load. The average fracture energy density G$\_$F/$\^$ave/ = 115 N/m occurred during the unstable crack propagation. The fracture process zones were fully developed at the crack length of 111㎜, and the sizes of fracture process zone for initial notches of 25.4㎜ and 6.4㎜ were 86㎜ and 105㎜, respectively. Average fracture energy densities of the resistance curves after full development of fracture process zone were 229 N/m for the initial notch of 25.4㎜ and 284 N/m for 6.4㎜. The values were more than twice of G$\_$F/$\^$ave/.

• Economic and Environmental Geology
• /
• v.37 no.6 s.169
• /
• pp.613-629
• /
• 2004

Contamination of groundwater by volatile organic compounds (VOCs) was investigated for 168 groundwater wells in Ulsan area to study the natural attenuation of organic compounds in the aquifers. As groundwater contamination by VOCs is closely related to land use, 168 groundwater samples were classified into 4 different groups; agricultural, forestry, industrial, and residential & business. From analysis 65 out of 168 groundwater samples contained more than one VOC. Analysis of samples were performed fir 36 halogenated aliphatic hydrocarbons and 25 petroleum hydrocarbons set up by NAWQA of US geological survey. Twelve petroleum hydrocarbons were detected in 26 groundwater wells, but their concentrations were less than 1.5 g/L except for MTBE. Twenty three chlorinated aliphatic hydrocarbons, composed of 11 methanes, 6 ethanes and 6 ethenes, were detected in 63 groundwater samples. The range of methanes concentration was $ND\~330\;/gL,\;ethanes\;ND\~84\;gL$, and PCE and their derivatives $ND\~62\;g/L$. As the study area was comprised of the aerobic/denitrification zones and $Fe^{+3}$ redox condition, most of petroleum hydrocarbons were degraded well, while halogenated hydrocarbons were slowly biodegradation.

• Economic and Environmental Geology
• /
• v.13 no.2
• /
• pp.91-103
• /
• 1980

In spite of the fact that the Okcheon system has been rather intensively studied by many geologists since 1945, it still remains as a controversal problem as to its stratigraphy and geologic age. Present study has mainly focused on the upper members of the Okcheon system, namely the Hwanggangri and the Kunjasan formations so as to clarify the lithology, the depositional environment and the tectonic evolution of the formations. The Kunjasan formation lying unconformably over the Hwanggangri formation which is supposed to be a meta-tillite is interpreted as a metamorphosed calcareous argillaceous and/or arenaceous sediments on contract to the idea postulated by some geologists that it was a derivative of silicified Hwanggangri formation. Lithology of the Kunjasan and the Hwanggangri formation is quite different in that the former is white in color, contains few pebbles, and mostly composed of diopside and detrital quartz, whereas the latter is black to dark in color, contains abundant and variable kinds of pebbles, and composed of more argillacous matrix that has been metamorphosed to hornfels. The Hwanggangri and the Kunjasan formations were deposited in the rather deep sea which has transgressed toward northeast from southwest in the late Precambrian time, and the writer (1970) had formerly designated it as Okcheon Paleogeosyncline. With the beginning of Paleozoic era, Okcheon neogeogyncline was formed to the northeast of the old paleogeogyncline area. The transgression of the sea had proceeded toward southwest in which Cambrian strata were accumulated. During this period the area occupied formerly by the paleogeosyncline was uplifted, so that most of the Hwanggangri and the Kunjasan formations were eroded away except in the area close to the neogeosyncline sea coast. This is the reason why the Hwanggangri and the Kunjasan formations are cropped out presently in the area of the vicinity of contact zone of the paleo- and neogeosyncline zones. The age of the Okcheon system has been reconfirmed to be Precambrian from the view of the facts that 1) the Hanggangri formation, the upper member of the Okcheon system is meta-tillite and correlated to the Precambrian tillite in the Yantze basin in China, 2) the Okcheon system has been moderately metamorphosed while other formations of the same age, if it is Paleozoic or later, have not been metamorphosed, and 3) tectonic history and limited areal distribution of the Hwanggangri and the Kunjasan formations is suggestive of Precambian age.

• Economic and Environmental Geology
• /
• v.45 no.5
• /
• pp.551-564
• /
• 2012

This study carried out palynological analysis and seismic interpretation to establish a stratigraphic and environmental reconstruction mainly based on fossil palynomorphs and seismic reflection data correlated with the oil exploation well (BP-1) located in the Sora Sub-basin. There were frequent environmental and floral changes due to sea level change in the Sora Sub-basin. The palynomorph assemblages found in the well sediments enabled paleoecological zonation of the well sediment sequence resulting in 4 zones: Ecozone III, Ecozone IV, Ecozone V, Ecozone VI. Index fossils among palynomorphs indicate geological ages of the units within the well ranging from Eocene to Pleistocene, and paleoenvironment varies from freshwater to inner neritic marine. Previous studies suggest that the marine deposits were slightly different in stratigraphic range from well to well. It is considered the difference is credited to geomorphological setting. This study also shows stratigraphic correlation between existing wells and BP-1 well to establishes a standard stratigraphy of the Domi Basin.