• Title/Summary/Keyword: MT survey

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A Short Seismic Reflection Survey for Delineating the Basement and the Upper Units of the Gomso Bay, Yellow Sea (곰소만 지역의 기반암 및 상부 층서 파악을 위한 시험 탄성파반사법 탐사)

  • Kim Ji-Soo;Ryang Woo-Hun;Han Soo-Hyung;Kim Hak-Soo
    • The Journal of Engineering Geology
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    • v.16 no.2 s.48
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    • pp.161-169
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    • 2006
  • A short seismic reflection survey was performed to map the basement and the upper units in the Gomso Bay. This research was mainly aimed at clarifying the basement by improving the signal-to-noise ratio in data processing steps. The strategies employed in this research included enhancement of the signal interfered with large-amplitude noise, through pre- and post-stack processing such as time-variant filtering, bad trace edit, careful muting after f-k filter and NMO correction. The subsurface structure mapped from this survey mainly consists of the top of basement and the upper three units, which were well correlated to the result from the previously conducted MT survey. Furthermore seismic section clarifies approximately 30m deep subhorizontal event of the top of the basement, which was not shown in the central portion of the MT section due to data qualify.

Vascular Plants Distributed in the Hanbuk-Jeongmaek - Focused on Mt. Gwangdeok, Mt. Cheonggye and Mt. Jukyeop - (한북정맥에 분포하는 관속식물상 - 광덕산, 청계산, 죽엽산을 중심으로 -)

  • Oh, Hyun-Kyung;Kim, Dong-Pil;You, Ju-Han
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.19 no.6
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    • pp.41-61
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    • 2016
  • This study was carried out to offer the basic data for establishing the management plan and constructing the ecological data by surveying and analysing the flora distributed in main survey sites(Mt. Gwangdeok, Mt. Cheonggye and Mt. Jukyeop), Hanbuk-Jeongmaek. The flora were summarized, numbering 659 taxa including 99 families, 341 genera, 575 species, 4 subspecies, 69 varieties and 11 forms. The rare plants were 16 taxa including Tylophora floribunda, Hanabusaya asiatica, Lilium cernuum, Belamcanda chinensis and so forth. The Korean endemic plants were 24 taxa including Salix koriyanagi, Aconitum pseudolaeve, Clematis trichotoma, Hosta minor and so forth. The specific plants by floristic region were 95 taxa including 32 taxa of grade I, 31 taxa of grade II, 25 taxa of grade III, 5 taxa of grade IV and 2 taxa of grade V. The naturalized plants were 38 taxa including Fallopia dumetorum, Silene armeria, Cosmos bipinnatus, Poa pratensis and so forth. The invasive alien plants were 4 taxa including Ambrosia artemisiifolia, Ambrosia trifida, Aster pilosus and Eupatorium rugosum.

Changes in adult and middle-age Missing Teeth Index in Korea during the last 10 years: Data from 2007 to 2019 of the National Health and Nutrition Examination Survey (최근 10년간 우리나라 청·중장년기 우식경험상실치아수의 변화: 국민건강영양조사 2007년~2019년 자료)

  • Kim, Gyu-Bin;Wi, Seung-Yeon;Choi, Youn-Hee;Jung, Yun-Sook
    • Journal of Korean society of Dental Hygiene
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    • v.22 no.4
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    • pp.241-247
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    • 2022
  • Objectives: This study aimed to determine the Missing Teeth (MT; mean number of missing permanent teeth) index experienced by year for adults between the ages of 19 and 64. Methods: This study was conducted by analyzing the raw data of participants in the 4th to 8th periods of the National Health and Nutrition Examination Survey (NHANES). For the statistical program, IBM SPSS / WIN 26 was used and an independent sample t-test was performed. Results: The average number of MT by year showed a decreasing trend. In 2007, 2008, 2010 and 2011, the average number of MT by sex was higher among females, and this was statistically significant (p<0.05). However, in 2019, males had a higher average number of MT than females, which was statistically significant (p<0.05). Conclusions: Males had a higher average number of MT than females in Korea, so it is considered that oral health programs or oral hygiene management according to sex are necessary.

Application of magnetotelluric survey for development of deep geothermal water at Seokmo Island, Korea (석모도 지열수 개발을 위한 자기지전류탐사의 적용)

  • Lee, Tae-Jong;Song, Yoon-Ho;Park, Deok-Won
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.4 no.1
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    • pp.1-10
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    • 2008
  • A magnetotelluric survey and geological survey have been performed to delineate deeply extended fracture systems at the geothermal field in Seokmo Island, Inchon, Korea. One borehole(BH-1) succeed to meet a large fracture system at the depth of 750 m where approximately $72^{\circ}C$ geothermal water is overflowing, while the other borehole(BH-2), which is about 200 m eastward from BH-1, failed to develop enough geothermal water even at the depth of 1,200m. Though there have been so many electric noise sources around the survey region, good quality of MT data above 1 Hz could be obtained with careful installation, remote reference processing. Inversion of MT data for two lines roughly perpendicular to the two major lineaments respectively show that the two lineaments are related to the fracture systems that are extended at least down to 1.5 km depth and inclined eastwards. From the interpretation, additional drilling for BH-2 is recommended and finally meet the fracture systems at the depth of 1,280 m and resulted in overflow of large amount of geothermal water of temperature $69.4^{\circ}C$ from BH-2.

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MT Response of a Small Island Model with Deep Sea and Topography (깊은 바다와 지형을 고려한 소규모 섬 모델의 MT 반응 연구)

  • Kiyeon Kim;Seong Kon Lee;Seokhoon Oh;Chang Woo Kwon
    • Geophysics and Geophysical Exploration
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    • v.27 no.1
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    • pp.37-50
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    • 2024
  • The magnetotelluric (MT) survey can be affected by external environmental factors. In particular, when acquiring MT data in islands, it is essential to consider the combined effect of topography and sea to understand the results and make accurate interpretations. To analyze the MT response (apparent resistivity, phase) with consideration of the effect of topography and sea, a small cone-shaped island model surrounded by deep sea was created. Two-dimensional (2-D) and three-dimensional (3-D) forward modeling were performed on the terrain model considering topography and the island model considering both topography and sea. The 2-D MT response did not reflect the topographic and sea effect of the direction orthogonal to the 2-D profile. The 3-D MT response included topographic and sea effects in all directions. The XY and YX components of the apparent resistivity were separated on undulating topography, such as a hill. A conductor at 1 km below sea level could be distinguished from topographic and sea effects in the MT response, and low resistivity anomaly was attenuated at greater depths. This study will facilitate understanding of field data measured on small islands.

An Evaluation of Natural-Ecological Function for Planning and Management on Forest (산림녹지의 계획 및 관리를 위한 자연생태적 기능 평가)

  • Lee, Woo-Sung
    • Journal of the Korean Institute of Landscape Architecture
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    • v.39 no.5
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    • pp.1-11
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    • 2011
  • Many studies which assessed the function of forest are focused on usage of citizen, but studies which focused on natural-ecological function still lack. Hence, the purpose of this study is to select and apply the evaluation indicators on natural-ecological function of forest as a base research for sustainable planing and management. First, the 35 indicators were selected by the review of the internal and external 56 literature. The 12 indicators among those were reselected as natural-ecological indicator by the first survey and 7 indicators such as green area, connectivity etc. were determined through MCB analysis by the second survey. Also, the weights of 7 indicators for the functional evaluation were computed using AHP analysis by the third survey. As aresult of AHP analysis, the naturality was showed the highest indicator by 0.189, while the NDVI was evaluated the lowest indicator by 0.063. According to the result of evaluating the natural-ecological function on forest in Daegu which was selected as suitable study area, the natural-ecological functions around the Mt. Ap and Mt. Chengryong, top of Mt. Biseul had more than 85 scores, so those were assessed as an excellent area. On the other hand, the functions around the western area of Mt. Waryong and Mt. Macheon, the Mt. Daeni of Dalseong-Gun had less than 50 scores, which means that the area had to be controled by sustainable management. Therefore, we will be able to utilize the basic data for the preservation and management at urban and environmental planning through the results of this study.

Analysis of the Main Habitat for Siberia Musk Deer (Moschus moschiferus) Restoration in Mt. Odae National Park, Korea (오대산국립공원 지역에 멸종위기종인 사향노루 복원을 위한 주요 서식지 분석에 관한 연구)

  • Park, Yong-Su;Kim, Jong-Taek;Lee, Woo-Shin
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.11 no.4
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    • pp.91-102
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    • 2008
  • This study was conducted to obtain the basic information about Siberia Musk Deer (Moschus moschiferus), and to establish a conservation area for the replacement of Siberia Musk Deer into Mt. Odea National Park, South Korea. We analyzed the main habitat for Siberia Musk Deer restoration in Mt. Odae National Park, Korea. We recorded Siberia Musk Deers' field signs (i.e., bedding sites, feeding areas, feces and tracks), and habitat variables such as nearest distance to the watercourse, trails, slope, aspect, forest type and land cover etc. from Dec. 2004 to Aug. 2007 in Mt. Jiri, Mt. Seorak, and Demilitarized Zone (DMZ). Rocky areas, ridges, mixed coniferous forest (Red pine and Mongolian oak), southern and southeastern slope, elevation of above 800m, and distance from watercourse shorter than 300m etc. were dominant habitat types of Siberia Musk Deer. Based on the significant habitat types, a proper conservation plan should be prepared for the restoration of habitats in order to reintroduce, and to increase the population of Siberia Musk Deer in Mt. Odea National Park, South Korea. Small population size, and limited ecological data are the major constraints for the establishment of conservation areas. Furthermore, other anthropogenic factors including human activities, poaching, and residential area around the park caused the difficulties to qualify as a conservation area. For the successful establishment of conservation area in the future, it is recommended to conduct a comprehensive ecological research, and to survey human disturbances including their impacts on the habitats of Siberia Musk Deer in the Mt. Odea National Park.

Above Ground Carbon Stock Through Palm Tree in the Homegarden of Sylhet City in Bangladesh

  • Dey, Anna;Islam, Mahmuda;Masum, Kaji Mohammed
    • Journal of Forest and Environmental Science
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    • v.30 no.3
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    • pp.293-300
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    • 2014
  • An explanatory survey was conducted to assess the contribution of palm species in carbon sequestration in the homegarden of the Sylhet Metropolitan City Corporation of Bangladesh. Assessment was done by means of two stage random sampling. A total of 10 housing area were selected randomly for the study and 4 common palm tree species were found abundantly. From the observations abundance of palm trees [Areca catechu (175/housing area), Cocos nucifera (145/housing area), Borassus flabellifer (124/housing area) and Phoenix sylvestris (27/housing area)] were found higher in all homesteads in comparison with other species. Study revealed that total organic carbon (MTOC mt/ha) was highest in Cocos nucifera (12.48 mt/ha), followed by Areca catechu (4.20 mt/ha), Borassus flabellifer (3.02 mt/ha) and Phoenix sylvestris (0.59 mt/ha). Total amount of organic carbon stored by palm trees in homestead areas was found 20.28 metric ton/ hector in the study area. Study revealed that palm trees of homestead forest accumulate a good amount of biomass and is a good sinker of organic carbon from the atmosphere. Proper management of palm trees will help to improve the local, national and international community through carbon sequestration.

An Investigation on the Flora and Life Form in Mt. Sori (소리봉의 지물상 및 생활형)

  • Lee, Nam Suk;Sung Hee Yeau
    • The Korean Journal of Ecology
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    • v.6 no.4
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    • pp.33-59
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    • 1983
  • An investigation has been performed on the flora and life form of the vascular plants at Mt. Sori in Kwangneung from March to November in 1982. In a survey field trip, 539 species, 344 genera, 102 families of plants. are collected. Among them Hylomecon vernale, Aconitum coreanum, A. pseudoproliferum, Adonis amurensis, Anemone raddeana is important plant in this area and they are becoming sparse than past. In the life form spectrum hemiryptophytes is 40.6%.

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The Vegetation of Mt. Choksang (赤裳山의 植生)

  • Kim, Chang-Hwan;Seon-Hee Kang;Bong-Seop Kil
    • The Korean Journal of Ecology
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    • v.14 no.2
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    • pp.137-148
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    • 1991
  • The forest vegation and their structural characteristics in mt. chokang were investgated by phytosociological survey and ordination. It was classified five forests such as quercus tschonoskii community and fraxinus mandshurica community and this result has confirmed to coincide with community ciassification by polar ordination. Chang of diversity index was shown to decase, whereas dominance index, to increase according to chang high altitude. By soil moisture gradient, distribution pattern of fraxinus mandshurica, acer mono, carpinus cordata was in moist, but quercus serrata,˘quercus variabilis and mongolica, dry habitats.

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