• Geophysics and Geophysical Exploration
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• v.25 no.3
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• pp.129-139
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• 2022

Analog-based streamers for ultra-high-resolution seismic surveys are capable of additional noise ingress in water, but the specifications cannot be expanded through interconnections. Foreign-produced digital streamers have been introduced and used primarily at domestic research institutes; however, the cost is high and smooth maintenance is challenging. This study investigates the localization of ultra-high-resolution digital streamers capable of high-resolution imaging of a geological structure. A digital streamer capable of 24-bit, 10 kHz digital sampling of up to 64 channel data was developed through research and development. Various quantitative specifications of the system were designed and developed close to the benchmark model, Geometrics' GeoEel streamer, and the number of modules that make up the system was drastically reduced, reducing development costs and making it easier to use. The field applicability of the developed streamer system was evaluated in an in situ experiment conducted in the waters around the Port of Yeong-il Bay in Pohang in April 2022.

• Geophysics and Geophysical Exploration
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• v.25 no.3
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• pp.109-119
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• 2022

The computational efficiency of reverse time migration (RTM) based on numerical modeling is not secured due to the high-frequency band of several hundred Hz or higher for data acquired through a three-dimensional (3D) ultra-high-resolution (UHR) seismic survey. Therefore, this study develops an RTM program to derive high-quality 3D geological structures using UHR seismic data. In the traditional 3D RTM program, an excitation amplitude technique that stores only the maximum amplitude of the source wavefield and a domain-limiting technique that minimizes the modeling area where the source and receivers are located were used to significantly reduce memory usage and calculation time. The program developed through this study successfully derived a 3D migration image with a horizontal grid size of 1 m for the 3D UHR seismic survey data obtained from the Korea Institute of Geoscience and Mineral Resources in 2019, and geological analysis was conducted.

• Journal of Environmental Impact Assessment
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• v.31 no.6
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• pp.449-464
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• 2022

This study reviewed the development process of the consultation guideline for the environmental assessment of offshore wind power. Based on this, implications and improvement plans for a future revision of the guidelines. Domestic and foreign case studies reviewed the consulting cases on domestic offshore wind power development projects, environmental location consulting cases, and guidelines related to overseas offshore wind power and analyzed location characteristics and significant environmental issues by project. Major environmental issues related to offshore wind power include birds, noise and vibration, marine animals and plants, marine physics, marine water quality and sediments, marine landscapes, and other auxiliary facilities installed on land. Implications and improvements for revising the consultation guidelines for evaluating offshore wind environments require data and clear guidelines at the central government level to determine areas where offshore wind projects can be located. In a situation where the importance of cumulative impact assessment is emphasized, guidelines for cumulative impact assessment methodologies for each item that reflect the domestic situation should be prepared for a cumulative impact assessment on offshore wind power environmental issues. In addition, when revising the consultation guidelines, empirical research cases should be reflected through the accumulation of environmental surveys and monitoring data of offshore wind farms by sea area.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2342-2344
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• 2005

초광대역 임펄스를 이용한 비파괴 지중 매설물 탐지용 지반 탐사 레이더(Ground penetrating image radar: GPR)를 개발하였다. 최대 탐사 깊이를 고려하여, 900 picosecond(ps) 상승 시간을 갖는 초광대역 임펄스를 설계하였고, 임펄스 발생기의 주파수 특성을 고려하여, 소형 평판형 다이폴 안테나가 설계되었다. 또한, 지중으로부터 반사되는 신호를 수신하기 위해서 고속의 A/D를 사용하였다. 측정은 송수신 안테나의 간격을 고정한 Bistatic 방식을 사용하였으며, 지중 매설물의 영상처리 판별을 위해 마이그레이션(migration) 기법을 사용하였다. 개발된 시스템은 금속 물체와 비금속 물체가 매설된 실증 시험장에서 시험되었고, 평면 해상도 및 깊이에 대한 해상도가 우수함을 보였다.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2023.11a
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• pp.297-298
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• 2023

해상 사고 시 지상에서 통상적으로 사용하는 빛이나 전파가 투과하지 못하는 수중에서 수중 음향을 이용해 수백 m 이상의 원거리에서 실종자나 화물의 위치를 추적하기 위해 요구되는 조건들을 분석하고 이를 실증하기 위해 인체에 부착 가능한 크기의 소형 수중 음향 송신기와 이를 찾기 위해 수색 작전에 사용하는 수신기가 제작됐다. 이를 사용해 서해 상에서 1km 거리에서 음향 신호 수신을 확인했고 실제 현장에서 적용되기 위해 필요한 개선점들을 정리했다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.13-14
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• 2016

Many ships' collision accidents occur due to unlawful action at sea. And also at shore traffic, many car collision accidents occur due to unlawful action. Therefore In this study we analyzes actual collision accidents at sea with the regards of liability. and search and analyze similar car collision accidents at shore traffic to compare it with the ship collision. In result, this study suggests the liabilities of the two different types accidents are needed to change more reasonable liability apportionment.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.344-346
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• 2022

최근 자율운항기술개발이 활발하게 이루어짐에 따라 자율운항선 실증이 증가하고 있으며, 또한 자율운항선의 효율적 운용 특히 운항의 안전성을 위해 입출항 시기의 적절성 또한 중요해지고 있다. 이에 해상교통혼잡도를 예측하고자 하였고, AIS 빅데이터를 통해 선박별항적을 분석 및 분류하고자 하였다. 장기적 관점에서 PORT-MIS 선박입출항현황 데이터(호출번호, 입항일시, 출항일시, 전출항지, 차항지, 계선지)를 과거 AIS 빅데이터와 연결시켜 과거 항적 중 가장 가까운 항적을 찾고자 하였다. 그리고 당시 소요 시간을 반영하여 12개의 시간대별로 어느 시점에 어느 위치 구간에 선박들이 놓이게 될지 예측하였고, 특히 입출항 시기의 적절성에 핵심이 되는 13개로 모델링된 영역에 몇 개의 선박들이 항로를 지나는지에 따라 혼잡도(원활, 혼잡, 정체)를 구분하였다. 또한, 본 연구에서는 단기적 관점에서 실제 AIS가 수신된 후에도 유사한 항적을 검사해가며 혼잡도를 예측하고자 하였고, 이러한 장단기적 혼잡도 예측을 통해 미래 자율운항선입출항 지원 서비스의 안전과 그 적절성을 제공하고자 하였다.

• Korea Trade Review
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• v.42 no.6
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• pp.131-154
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• 2017

In international trade, transportation generally has the largest and direct impact on freight costs. However, it is also sensitive to external factors such as global economic conditions, global trade volume and exchange rate. Therefore, it is necessary to examine the relationship and influence of international trade in terms of external factors that affect the change of imports and exports by marine and air transportation through empirical analysis. In particular, the analysis of the impact of these external factors on marine and air transportation is an important topic when recent exchange rate changes are significant, and it is also necessary to analyze what transportation means are more sensitive to exchange rate changes. In this study, we use the Vector Error Correction Model to analyze the dynamic effects of changes in exchange rate and domestic and international economic conditions on marine and air transportation from January 2000 to March 2017. Respectively. Alos, Impulse response function and variance decomposition were examined.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.6
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• pp.141-156
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• 2023

This study aims to improve understanding of freight movement, crucial for logistics facility investment and policy making. It addresses the limitations of traditional freight truck traffic data, aggregated only at city and county levels, by developing a new methodology. This method uses trip chain data for more detailed, facility-level analysis of freight truck movements. It employs DTG (Digital Tachograph) data to identify individual truck visit locations and creates H3 system-based polygons to represent these visits spatially. The study also involves an algorithm to dynamically determine the optimal spatial resolution of these polygons. Tested nationally, the approach resulted in polygons with 81.26% spatial fit and 14.8% error rate, offering insights into freight characteristics and enabling clustering based on traffic chain characteristics of freight trucks and visited facility types.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.181.1-181.1
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• 2010

풍력터빈에서 전력생산량은 속도의 세제곱에 따라 바람의 속도에 크게 영향 받는다. 본 연구에서는 기상청에서 제공하는 새만금 인근 해안의 2005부터 2007년까지의 AWS(지역별 관측자료)와 해양에서 떨어진 새만금 서해의 2000년부터 2009년까지 QuikSCAT위성 데이터를 이용하여 속도에 따른 확률 밀도 분포를 획득하였다. 측정된 관측 데이터는 80m 높이에서의 보정 자료를 근거로 하였으며, IEC 61400-12와 13을 근거로 실증단지 적합성에 대한 분석을 하였다.