• Title/Summary/Keyword: 울릉도

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Trace Interpolation using Model-constrained Minimum Weighted Norm Interpolation (모델 제약조건이 적용된 MWNI (Minimum Weighted Norm Interpolation)를 이용한 트레이스 내삽)

  • Choi, Jihyun;Song, Youngseok;Choi, Jihun;Byun, Joongmoo;Seol, Soon Jee;Kim, Kiyoung;Lee, Jeongmo
    • Geophysics and Geophysical Exploration
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    • v.20 no.2
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    • pp.78-87
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    • 2017
  • For efficient data processing, trace interpolation and regularization techniques should be antecedently applied to the seismic data which were irregularly sampled with missing traces. Among many interpolation techniques, MWNI (Minimum Weighted Norm Interpolation) technique is one of the most versatile techniques and widely used to regularize seismic data because of easy extension to the high-order module and low computational cost. However, since it is difficult to interpolate spatially aliased data using this technique, model-constrained MWNI was suggested to compensate for this problem. In this paper, conventional MWNI and model-constrained MWNI modules have been developed in order to analyze their performance using synthetic data and validate the applicability to the field data. The result by using model-constrained MWNI was better in spatially aliased data. In order to verify the applicability to the field data, interpolation and regularization were performed for two field data sets, respectively. Firstly, the seismic data acquired in Ulleung Basin gas hydrate field was interpolated. Even though the data has very chaotic feature and complex structure due to the chimney, the developed module showed fairly good interpolation result. Secondly, very irregularly sampled and widely missing seismic data was regularized and the connectivity of events was quite improved. According to these experiments, we can confirm that the developed module can successfully interpolate and regularize the irregularly sampled field data.

Regression models on flood damage records by rainfall characteristics for regional flood damage estimates (지역별 홍수피해추정을 위한 강우특성에 대한 홍수피해자료의 회귀모형)

  • Lim, Yeon Taek;Choi, Hyun Il
    • Journal of Wetlands Research
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    • v.22 no.4
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    • pp.302-311
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    • 2020
  • There are limitations to cope with flood damage by structural strategies alone because both frequency and intensity of floods are increasing due to climate change. Therefore, it is one of the necessary factors in the nonstructural countermeasures to collect and analyze historical flood damage records for the future flood damage assessments. In order to estimate flood damage costs in Gyeongsangbuk-do where severe flood damage occurs frequently due to geographical and climatic effects, this paper has performed the regression analysis on flood damage records over the past 20 years (1999-2018) by rainfall characteristics, which is one of the major causes of flood damage. This paper has then examined the relationship between the terrain features and rainfall characteristics in the regional regression functions, and also estimated the flood damage risk for 100-year rainfall by using the regional regression functions presented for the 22 administrative districts in Gyeongsangbuk-do excluding Ulleung-gun. The flood damage assessment shows that the relatively high damage risk is estimated for county areas adjacent to the eastern coast in Gyeongsangbuk-do. The regional damage estimate functions in this paper are expected to be used as one of the nonstructural countermeasures to estimate flood damage risk for the design or forecasting rainfall data.

Extraction and Purification of Agar from Gelidium amansii (우뭇가사리로부터 한천의 추출 및 정제)

  • Do Jeong-Ryong
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.30 no.3
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    • pp.423-427
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    • 1997
  • The effect of different treatments on the quality and yield of purified agar produced from Gelidium amansii has been studied, and the extraction condition ol agar produced from G. amansii has been examined. The contents of ash, sulfate in agar produced from g. amansii collected from different places were $2.63\~2.92\%\;and\;1.38\~1.78\%$, respectively. Yields and gel strength of agar produced from G. amansii collected from different places were $31.6\~46.8\%\;and\;496\~887g/cm^2$, respectively. It was effective to extract agar at $120^{\circ}C\;for\;2\~3hrs$. Agar was purified by D.W. washing, EDTA washing, chitosan treatment, CPC treatment, PEG treatment, ethanol precipitation, acetone precipitation and propanol precipitation. The mineral contents of agar produced from Gelidium amansii were Na (2934ppm), Ca (2472ppm), Mg (2259ppm), K (2527ppm), P1(81.1ppm), Fe (66.4ppm), Al (71.7ppm), Zn (29.7ppm) and Pb (ND: not detected), respectively.

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Zero-Offset VSP Data Processing for Gas Hydrate-Bearing Sediments in East Sea (동해 가스하이드레이트 부존지역 제로오프셋 VSP 탐사 자료의 자료처리)

  • Kim, Myung-Sun;Byun, Joong-Moo;Yoo, Dong-Geun
    • Geophysics and Geophysical Exploration
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    • v.12 no.3
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    • pp.255-262
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    • 2009
  • Conventionally, vertical-seismic-profiling (VSP) survey that provides high-resolution information has mainly performed to obtain the exact depth of the gas hydrate-bearing sediment, which is one of the key factors in the development of the gas hydrate. In this study, we extracted interval velocities and created corridor stacks from the first domestic zero-offset VSP data, which were acquired with three component receivers at UBGH09 borehole in Ulleung Basin where gas hydrate exists. Then we compared the corridor stacks with a CMP stacked section from surface seismic data. First of all, we converted the signals recorded with three component receivers to true vertical and horizontal components by phase rotation, and divided the data into direct waves and reflected waves by wavefield separation processing. The trend of the interval velocity extracted from the zero-offset VSP was similar to that of the sonic log obtained at the same borehole. Because the interval velocity of the gas hydrate-bearing sediment above the BSR was high, and it decreased suddenly through the BSR, we could infer that free gas is accumulated below the BSR. The results of comparing the corridor stacks to the CMP stacked section of the surface seismic data showed that most reflection events agreed well with those in the surface CMP stacked section and that the phase-rotated VSP data corresponded better with the surface seismic data than the VSP data without phase rotation. In addition, by comparing a corridor stack produced from the transverse component with the CMP stacked section of the surface seismic data, we could identify PS mode-converted reflections in the CMP stacked section.

Genetic variation in five species of Korean Orostachys (Crassulaceae) (한국산 바위솔속(돌나물과) 5종에 대한 유전적 변이)

  • Kim, Hyung-Deok;Park, Ki-Ryong
    • Korean Journal of Plant Taxonomy
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    • v.35 no.4
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    • pp.295-311
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    • 2005
  • Starch gel electrophoretic studies using 24 populations of five Korean Orostachys species were conducted to investigate allozyme variation and to test hypotheses of systematic relationships among species. The resulting phenogram showed that the populations of five Korean Orostachys species were divided into two major groups. And they were concordant with molecular and morphological data in suggesting that Orostachys was divided into two groups corresponding to the subsect. Appendiculatae and subsect. Orostachys. The low genetic identities among Korean Orostachys species indicated that the species of Orostachys have diverged gradually through the model of geographical species. Comparing the previous genetic data from the species with similar life history and mode of reproduction, most of Korean Orostachys species revealed a significant low genetic variation, while the widespread O. japonicus showed a relatively high genetic variation among the Korean species. This kind of genetic variation pattern might be the results of the isolated habitats, limited numbers of individuals within the populations, destruction of habitats, inbreeding and asexual reproduction in Korean Orostachys populations. The Jungdongjin population (POP 21) of O. malocophyllus was genetically unrelated with remaining populations of the same species, and this interpretation was consistent to the results from the previous palynological and morphological studies. Our allozyme data supported the taxonomic treatment of recently proposed taxa, O. iwarenge (Makino) Hara for. magnus and O. margaritifolius.

Application of Deconvolution Methods to Improve Seismic Resolution and Recognition of Sedimentary Facies Containing Gas Hydrates (동해 가스하이드레이트 퇴적상 해석 및 분해능 향상을 위한 디컨볼루션 연구)

  • Yi, Bo-Yeon;Lee, Gwang-Hoon;Kim, Han-Joon;Jeong, Gap-Sik;Yoo, Dong-Geun;Ryu, Byoung-Jae;Kang, Nyeon-Keon
    • Geophysics and Geophysical Exploration
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    • v.13 no.4
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    • pp.323-329
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    • 2010
  • Three deconvolution methods were applied to stacked seismic data obtained to investigate gas-hydrates in the Ulleung Basin, East Sea: (1) minimum-phase spiking deconvolution, (2) minimum-phase spiking deconvolution using an averaged wavelet from all traces, and (3) deterministic deconvolution using a wavelet with phases computed from well-logs. We analyzed the resolving property of these methods for lithological boundaries. The first deconvolution method increases temporal resolution but decreases lateral continuity. The second method shows, in an overall sense, similar results to the spiking deconvolution using a minimum phase wavelet for each trace; however, it results in a more consistent and continuous bottom-simulating reflector (BSR) and better resolved sub-BSR reflectors. The results from the third method reveal more detailed internal structures of debris-flow deposits and increased continuity of reflectors; in addition, the seafloor reflection and the BSR appear to have changed to a zero-phase waveform. These properties help more precisely estimate the distribution and reserves of gas hydrates in the exploration area by improving analysis of facies and amplitude of the BSR.

Seismic Data Processing Suited for Stratigraphic Interpretation in the Domi Basin, South Sea, Korea (남해 대륙붕 도미분지 탄성파자료의 층서해석을 고려한 전산처리)

  • Cheong, Snons;Kim, Won-Sik;Koo, Nam-Hyung;Lee, Ho-Young;Shin, Won-Chul;Park, Keun-Pil
    • Economic and Environmental Geology
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    • v.43 no.6
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    • pp.603-613
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    • 2010
  • The Domi Basin in the South Sea of Korea is located between the Jeju Basin and Ulleung Basins, and is characterized by several sediment sags that are interested to have formed by crustal extension. This paper aims to derive an optimized seismic data processing procedure which helps stratigraphic interpretation of the Domi Basin. In particular, our data processing flow incorporated horizon velocity analysis (HVA) and surface-relative wave equation multiple rejection (SRWEMR) to improve the quality of stack section by enhancing the continuity of reflection events and suppressing peg-leg multiples respectively. As a result of processing procedures in this study, unconformities were recognized in the stack section that defines the early and middle Miocene, Eocene-Oligocene sequences. In addition, the overall quality of the stack section was increased as essential data to investigate the evolution of the basin. The suppression of multiple resulted in the identification of the Cretaceous basement. The data processing scheme evaluated through this study is expected to improve the standardization of processing sequences for seismic data from the Domi and adjacent Sora and north-Sora Basins.

Data Processing using Anisotropic Analysis for the Long-offset Marine Seismic Data of the East Sea, Korea (동해 해역 원거리 해양탄성파 탐사자료의 이방성 분석을 이용한 전산처리)

  • Joo, Yonghwan;Kim, Byoung-yeop
    • Geophysics and Geophysical Exploration
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    • v.23 no.1
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    • pp.13-21
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    • 2020
  • The acquisition and processing of long-offset data are essential for imaging deep geological structures in marine seismic surveys. It is challenging to derive an accurate subsurface image by employing conventional data processing to long-offset data owing to the normal moveout (NMO) stretch and non-hyperbolic moveout phenomena induced by seismic anisotropy. In 2017, the Korea Institute of Geoscience and Mineral Resources conducted a simultaneous two-dimensional multichannel streamer and ocean-bottom seismic survey using a 5.7-km streamer and an ocean-bottom seismometer to identify the deep geological structure of the Ulleung Basin. Herein, the actual geological subsurface structure was obtained via the sequential iterative updating of the velocity and anisotropic parameters of the long-offset data obtained using a multichannel streamer, and anisotropic prestack Kirchhoff migration was performed using the updated velocity and anisotropic parameters as input parameters. As a result, the reflection energy in the long-offset traces, which showed non-hyperbolic moveout owing to seismic anisotropy, was well aligned horizontally and NMO stretches were also reduced. Thus, a more precise and accurate migrated image was obtained, minimizing the distortion of reflectors and mispositioned reflection energy.

Projection of Future Heating and Cooling Degree Days over South Korea under the IPCC SRES Scenarios: An Experiment with CCSM3 and MM5 Models (IPCC SRES 시나리오에 따른 우리나라의 미래 냉난방도일 전망: CCSM3와 MM5 모델 활용)

  • Choi, Jin Young;Song, Chang Kun;Kim, Deok Rae;Hong, Sung Chul;Hong, Yoo Deog;Lee, Jae Bum
    • Journal of Climate Change Research
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    • v.4 no.2
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    • pp.141-158
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    • 2013
  • In this study, the projection of future heating and cooling degree days (HDDs and CDDs) has been conducted over South Korea for the period 1996~2005 with 2046~2055 and 2091~2100, using CCSM3 and MM5 simulations driven by the six IPCC SRES emission scenarios (A2, A1B, A1FI, A1T, B1, and B2). Annual mean surface air temperature increases by $1.2{\sim}3.4^{\circ}C$ at the end of the 21st century comparing to the present-day (1996~2005) in South Korea. HDDs decrease by 8~25% and CDDs increase up to 242~1,448% with corresponding changes in temperature. These increases and decreases also change the duration of HDDs and CDDs. HDDs duration decreases by 1 month, while the expansion of CDDs duration is much longer than 2 months. Thus, projected future HDDs and CDDs changes appear that cooling energy demand in summer season would increase and heating energy demand in winter would decrease in the future. Especially, these remarkable changes would be obvious at high mountain area, Gangwon-do and at south area, Jeju island. In the sense of future energy supply and policy, electrical energy for cooling in summer could be getting much more its importance rather than fossil energy used for heating in winter.

Effects of Heavy Metal Concentrations on Seed Germination and Rhizome Development of Campanula takesimana Nakai (중금속 농도가 섬초롱꽃 종자 발아 및 유근 발달에 미치는 영향)

  • Kim, Tae Hyun;Kim, Do Hyun;Im, Hyeon Jeong;Choi, Kyu Seung;Kim, Sang Geun;Song, Chi Hyeon;Oh, Beom Seok;Kim, Yang Su;Song, Ki Seon;Won, Chang O
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2019.10a
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    • pp.39-39
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    • 2019
  • 섬초롱꽃은 울릉군에 한정적으로 분포하는 여러해살이풀이다. 산림청에서는 약관심종(LC) 등급의 희귀식물이자 특산식물로 분류하고 있으며, 꽃의 관상가치가 특히 높아 화단용 소재, 절화용, 화분재배 등으로 흔히 이용되고 있다. 따라서 본 연구는 섬초롱꽃의 대량증식 시, 중금속이 미칠 수 있는 영향에 대해 파악하고자 수행하였다. 실험에 사용한 중금속은 카드뮴(Cd), 철(Fe) 두 종류이며, 두 종류 모두 1% 한천(agar)배지에 10, 25, 50, 100, 200 mg/L 농도로 녹여 사용하였다. 발아율 및 유근 생장을 위해 종자 및 유묘를 치상 후, $25^{\circ}C$ 항온 생장상에서 발아율 및 유근 발달을 관찰하였다. 발아율 측정결과, 아무처리도하지 않은 1% 한천(agar) 배지에서 $62.7{\pm}7.4%$로 가장 높았고 중금속 농도가 높아질수록 감소하였다. 카드뮴(Cd) 처리구에서는 10, 25, 50, 100, 200 mg/L 농도에서 각각 $17.3{\pm}1.3$, $2.7{\pm}1.3$, $1.3{\pm}1.3$, 0, 0%로 나타났다. 한편, 철(Fe) 처리구에서는 10, 25, 50, 100, 200 mg/L 농도에서 각각 $46.7{\pm}4.8$, $24.0{\pm}2.3$, $36.0{\pm}6.9$, $20.0{\pm}2.3$, 0%로 나타났다. 유근의 평균 생장 길이(mm)는 아무처리도 하지 않은 1% 한천(agar) 배지에서 19.6 mm로 가장 높았고, 중금속 농도가 높아질수록 낮게 나타났다. 카드뮴(Cd) 처리구에서는 10, 25, 50, 100, 200 mg/L 농도에서 각각 4.6 mm, 1.9 mm, 0.7 mm, 0.9 mm, 0 mm 생장한 것으로 나타났다. 한편, 철(Fe) 처리구에서는 10, 25, 50, 100, 200 mg/L 농도에서 각각 15.9 mm, 8.6 mm, 8.1 mm, 0.9 mm, 0 mm 생장한 것으로 나타났다. 실험결과를 종합해 볼 때, 섬초롱꽃 종자 발아 및 유근 생장의 억제는 카드뮴(Cd) 처리구에서 높게 나타났고, 철(Fe) 처리구에서는 비교적 영향을 덜 미치는 것으로 나타났다. 특히 카드뮴은 10 mg/L 농도만 처리하더라도 약 3.6~4.2배의 발아율 생장율 감소가 나타나, 섬초롱꽃 대량증식 시, 치명적일 것으로 판단된다. 본 실험의 결과는 섬초롱꽃 종자를 이용한 대량증식 및 유묘재배에 있어, 토양을 선택하는데 중요한 기초자료로서 활용될 것으로 기대된다.

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