• Geophysics and Geophysical Exploration
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• v.23 no.3
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• pp.168-177
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• 2020

Seabed multiple reflections (seabed multiples) are the main cause of misinterpretations of primary reflections in both shot gathers and stack sections. Accordingly, seabed multiples need to be suppressed throughout data processing. Conventional model-driven methods, such as prediction-error deconvolution, Radon filtering, and data-driven methods, such as the surface-related multiple elimination technique, have been used to attenuate multiple reflections. However, the vast majority of processing workflows require time-consuming steps when testing and selecting the processing parameters in addition to computational power and skilled data-processing techniques. To attenuate seabed multiples in seismic reflection data, input gathers with seabed multiples and label gathers without seabed multiples were generated via numerical modeling using the Marmousi2 velocity structure. The training data consisted of normal-moveout-corrected common midpoint gathers fed into a U-Net neural network. The well-trained model was found to effectively attenuate the seabed multiples according to the image similarity between the prediction result and the target data, and demonstrated good applicability to field data.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.427-428
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• 2008

In order to probe such mineral resources, AUVs (Autonomous Underwater Vehicles) have been used instead of ROVs (Remotely-Operated Vehicles) that are not suitable to probe submarine resources distributed over a wide area. However, the power consumption of AUVs needs to be reduced as they are operated by batteries. In controlling the power of underwater vehicles, the efficiency of batteries and their capacity have been heightened. This study aimed at developing a power control system suitable to the prober for submarine mineral resources. As a result, power was reduced as compared to the non-control system and the prober could explore the seabed longer than usual.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.177-179
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• 2012

이 연구의 목적은 우리나라 해상교통 안전확보를 위하여 전국 주요 항만 해역에 대한 수로측량의 긴급성과 중요성의 기준을 객관적으로 마련해 보는 것이다. 즉 전국의 관할 항만 해역별로 중요성과 위험성, 다양한 이용 고객들 수요의 긴급성과 중요성 등을 고려하여, 수로측량 우선순위(survey priorities)를 설정하고 객관적이고 합리적인 모델을 만들어 보는 것이다. 이를 위해 항만해역 수로측량의 변천과 현황, 기존의 문제점을 살펴보고, 문헌연구와 해외의 해양선진국 수로측량 사례를 통하여 잠정기준을 도출하였다. 그리고 이를 전문가 설문조사 및 분석을 통해 우선순위를 도출하였다. 그 결과 우리나라 주요 항만해역의 수로측량 우선순위로는 해저지형 변화, 해상교통량, 기존 수로측량 실적, 이해당사자/이용자의 요구, 해양사고, 해양환경 및 생태자원 보존 등으로 나타났다. 결론적으로 본 연구는 우리나라에서 향후 수로측량을 보다 과학적이고 체계적인 방법으로 수행하기 위한 모델을 만들어보고, 여러 정책적 제안을 하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.603-610
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• 2011

Yeosu area from the old historical monuments and artifacts related communications signal station, directions display panels, lighthouse, Geomundo the first submarine cable installation, etc. That appears in old documents and communications of the area should check the history and development of communication in understanding the Yeosu area and communicate the need to identify resources historicity.

• The Journal of the Acoustical Society of Korea
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• v.35 no.6
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• pp.419-426
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• 2016

Measurements of bottom loss as a function of grazing angle (in range of $9{\sim}14^{\circ}$) at a frequency range of 4 ~ 8 kHz were conducted on an experimental site off Geoje island in October 2015. Geoacoustic inversion of the surficial sediment thickness is performed using the arrival time difference between the surficial layer and the sub-bottom layer reflected signal. To invert the thickness of surficial sediment, we used the grain size of $8{\sim}10{\phi}$ obtained by KIGAM (Korea Institute of Geoscience and Mineral Resources). The thickness of the surficial sediment was estimated to be 4 ~ 7 m. Finally, this inversion result was compared with the geoacoustic observation conducted by the KIOST (Korea Institute of Ocean Science & Technology) using sub-bottom profiler.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2010.06a
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• pp.105-109
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• 2010

전 세계적으로 육상자원의 고갈로 해양광물을 개발하고 이를 경제적으로 활용하려는 움직임이 점점 증가하고 있다. 이에 우리나라도 한반도 주변 해역의 해양광물자원을 확보하기 위한 탐사와 연구가 진행 중에 있다. 특히 우리나라는 삼면이 바다로 둘러싸인 지형학적 특정으로 주변국과의 자원경쟁이 불가피하여 전략적 체계적 탐사자료의 관리와 이를 활용하기 위한 방안이 필요하다. 하지만 탐사 분야가 다양하고 그에 따른 데이터가 상이하여 관리에 어려움이 있다. 현재 국내에서 해양자원에 대한 정밀탐사가 이루어지고 과학적인 정보제공이 요구됨에 따라 해양광물자원정보시스템이 구축 운영되고 있지만 몇 가지 제약점이 존재한다. 따라서 본 연구에서는 이를 보완하기 위해 특히 시추 퇴적물 탐사 분야에 있어 GIS기반의 표출 가능한 대상항목을 분류하였고, 데이터베이스 구축을 위한 모델링을 진행하였다. 이는 위치기반의 분석결과 자료를 제시할 수 있도록 하였다 본 연구는 해저 퇴적층에 분야의 과학적 정보 제공을 위한 기반을 마련하였다는데 의의가 있다. 또한, 한반도 주변에 해양광물자원의 부존 가능 지역을 파악하는데 있어 과학적 정보를 지원하고 나아가 광물자원의 매장량 추정이나 경제성 평가를 위한 정보제공의 기반이 될 것으로 사료된다. 향후 연구에서는 시추퇴적물의 깊이에 따른 데이터베이스 관리 방안과 더불어 3차원 정보 제공에 대한 연구와 모델링 결과를 통해 실제 데이터에이스 구축이 진행되어야 할 것이다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.2
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• pp.149-155
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• 2011

As the depletion of land resources, the attention about marine resources has been focused on. Neighboring countries such as Japan and China to expand their marine territory invest more governmental money. The exact territorial sea baselines can be the scientific data which cad resolve the dispute between the neighboring countries. So, those territorial sea baselines should be maintained systematically and continuously. Because territorial sea baselines surveyed 10 years ago without updating, the review may be needed. In this study, we compared 2009 year surveying results with past territorial sea baselines results for reviews. As a results, Jeju Island represents a large difference. So, the outputs of territorial sea baselines around Jeju Island should be readjusted. Through this study, the ongoing maintenance of the territorial sea baselines is required. The continuing interest in the maritime boundary, as well as defend in terms of protection for undersea resources are needed.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.10a
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• pp.19-22
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• 2003

통발어업은 어구 조작을 위한 선박 의존도가 적고, 어구를 예인하지 않아 배의 속력이나 기관 마력을 그다지 크게 할 필요성이 없으므로 유류 사용량이 적으며, 저인망이나 연승 등으로 조업이 곤란한 기복이 심한 해저나 심해에서도 조업이 가능하다는 장점이 있다. 본 연구실에서는 통발 어구에 대해 미성어를 탈출하게 하여 보호하고, 성숙한 개체만을 선택적으로 어획할 수 있는 자원관리형 통발 어구어법 개발에 관한 연구가 수행 중에 있으며, 현장실험을 통해 어구에 대한 어획선택성, 자원상태와 어획강도 등에 관한 연구를 수행하고 있다. (중략)

• Economic and Environmental Geology
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• v.41 no.6
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• pp.747-761
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• 2008

In order to experiment the acoustic remote classification of seabed sediment, we achieved ground-truth data(i.e. video and grab samples, etc.) and developed post-processing for automatic classification procedure on the basis of 300 kHz MultiBeam Echo Sounder(MBES) backscattering data, which was acquired using KONGBERG Simrad EM3000 at Sock-Cho Port, East Sea of South Korea. Sonar signal and its classification performance were identified with geo-referenced video imagery with the aid of GIS (Geographic Information System). The depth range of research site was from 5 m to 22.7 m, and the backscattering amplitude showed from -36dB to -15dB. The mean grain sizes of sediment from equi-distanced sampling site(50 m interval) varied from 2.86$(\phi)$ to 0.88(\phi). To acquire the main feature for the seabed classification from backscattering amplitude of MBES, we evaluated the correlation factors between the backscattering amplitude and properties of sediment samples. The performance of seabed remote classification proposed was evaluated with comparing the correlation of human expert segmentation to automatic algorithm results. The cross-model perception error ratio on automatic classification algorithm shows 8.95% at rocky bottoms, and 2.06% at the area representing low mean grain size.

• Geophysics and Geophysical Exploration
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• v.2 no.4
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• pp.184-190
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• 1999

A study of gas hydrate is a worldwide popular interesting subject as a potential energy source. A seismic survey for gas hydrate have performed over the East sea by the KIGAM since 1997. General indicators of natural submarine gas hydrates in seismic data is commonly inferred from the BSR (Bottom Simulating Reflection) that occurred parallel to the see floor, amplitude decrease at the top of the BSR, amplitude Blanking at the bottom of the BSR, decrease of the interval velocity, and the reflection phase reversal at the BSR. So the seismic data processing for detecting gas hydrates indicators is required the true amplitude recovery processing, a accurate velocity analysis and the AVO (Amplitude Variation with Offset) analysis. In this paper, we had processed the field data to detect the gas hydrate indicators, which had been acquired over the East sea in 1998. Applied processing modules are spherical divergence, band pass filtering, CDP sorting and accurate velocity analysis. The AVO analysis was excluded, since this field data had too short offset to apply the AVO analysis. The accurate velocity analysis was performed by XVA (X-window based Velocity Analysis). This is the method which calculate the velocity spectrum by iterative and interactive. With XVA, we could determine accurate stacking velocity. Geobit 2.9.5 developed by the KIGAM was used for processing data. Processing results say that the BSR occurred parallel to the sea floor were shown at $367\~477m$ depths (two way travel time about 1800 ms) from the sea floor through shot point 1650-1900, the interval velocity decrease around BSR and the reflection phase reversal corresponding to the reflection at the sea floor.