• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.5
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• pp.195-202
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• 2021

Offshore wind turbine (OWT) receive a combined vertical-horizontal- moment load by wind, waves, and the structure's own weight. In this study, the bearing capacity for the combined load of the suction foundation of OWT installed on the sandy soil was calculated by finite element analysis. In addition, the stress state of the soil around the suction foundation was analyzed in detail under the condition that a combined load was applied. Based on the results of the analyses, new equations are proposed to calculate the horizontal and moment bearing capacities as well as to define the capacity envelopes under general combined loads.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.287-288
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• 2015

부산해역은 부산북항과 부산신항 해상교통관제 구역으로 구분되어 있다. 이 부산해역 관제구역의 설정은 해상교통흐름에 기초하여 해양사고 위치 등 여러 가지 고려 요소에 의하여 설정되는 것이 바람직하다. 이 연구에서는 부산해역 관제구역내의 해상교통흐름, 해양사고분석, 위험도 분석, 외국관제구역 사례 조사 등을 기반으로 하여 부산해역 관제구역의 적합성을 검토하여야 하는 당위성을 제시하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.271-272
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• 2018

부산항 신항은 현재 21개의 선석 규모에서 2030년까지 총 40선석까지 확대할 계획을 갖고 있다. 항만의 확대에 따라 선박 통항량 증가가 예상되며, 이를 대비해 해상교통관제도 해상교통량을 기반으로 집중관제구역을 설정할 필요가 있다. 본 연구는 부산항 신항을 대상으로 해상교통위험도 모델을 이용해 위험구역을 정량화하고 집중적으로 관제가 필요한 구역을 도출하는 것을 목적으로 한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.289-289
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• 2018

해상교통관제사의 역량기반 교육훈련의 실시를 위해 개인의 역량을 파악하고 조직이 요구하는 수준에 대하여 개인에게 필요한 맞춤형 교육을 실시하는 것은 해상교통안전을 증진시키고 조직 내 전략적 인적자원관리를 위해 중요하다. 본 연구에서는 신임 해상교통관제사의 역량기반 교육훈련 과정 개발을 위한 기초연구로서 국가직무능력표준(NCS, National Conpetency Standards)과 IALA 권고서 V-103/1에서 제시된 해상교통관제사의 직무역량을 통합하여 하나의 역량모델로 구성하고자 하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2021.11a
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• pp.81-82
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• 2021

선박은 건조 후 선주에게 인도되기 전에 해상시운전을 하게 된다. 해상 시운전은 통상 안벽에서 수행 가능한 기기류를 테스트 한 후 해상에서 실시하는 것으로 메인 엔진의 출력, 발전기를 포함한 각종 보조기계의 작동상태, 선박의 조종성능과 속력 테스트, 항해 통신장비 테스트, 양묘기테스트 등이 있으며 이외에 선종에 따른 추가 테스트 또는 선주에 의하여 요구하는 특별한 테스트를 하기도 한다. 본 연구는 해상 시운전의 주요 테스트 내용 중 선박조종성능에 관하여 분석하고, 실제 선박을 운항하는 항해사에게 필요한 주요 정보를 식별하고자 하는 기초연구로 진행되었다.

• Journal of the Korean GEO-environmental Society
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• v.14 no.4
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• pp.59-66
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• 2013

The foundation of offshore wind energy system is generally assumed to be fixed-ended in system analysis for the convenience of calculation and, correspondingly, it might lead a conservative design. If soil-foundation interaction get involved with the analysis, the system characteristics such as natural frequency, shear force, moment and displacement are expected to differ from those of fixed-ended case. In this study, the analysis have been conducted to identify how the response of offshore wind turbine varies upon considering the foundation flexibility with soil-foundation interaction. The model taking account of the flexibility of foundation was compared with fixed-ended model at the seabed. The flexibilities of foundation were obtained by coupled spring model at the seabed and Winkler Spring Model with soil depth. As a result, the first mode of the whole system with the Winkler Spring Model was decreased relative to that with the fixed-ended model. The results showed that the effect of foundation flexibility should be considered when designing the offshore wind energy system.

• Journal of the Society of Disaster Information
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• v.8 no.2
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• pp.138-147
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• 2012

In this paper, the various parametric study of collisions between a offshore wind tower and vessels were performed to estimate the ultimate behaviors of the bucket foundation and the tower. Additionally, the stability of the foundation and the energy dissipation capacities of the tower were analyzed. The results shows that the collision energy of the vessel was mainly dissipated by the plastic deformation energy of the tower and the foundation system shown enough bearing capacity against to this severe loading condition.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.4
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• pp.343-350
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• 2015

Extensive discussion on the optimal types of offshore wind turbine(OWT) among monopile, tripod and jacket in the intermediate depth of water has been actively carried out in worldwide wind turbine industry. Selecting the optimal types of OWT among several substructural types, it is required to consider the economic and technical feasibility including dynamically stable design of a wind turbine system. In this study, the effects of loading levels and uncertainties of soil properties on the natural frequency of OWT have been quantitatively investigated. In conclusion, the natural frequency of monopile-type OWTs has a significant level of uncertainty, hence it is very important to minimize the level of uncertainties in soil properties when the monopile is selected as a foundation for an OWT.

• Journal of the Society of Disaster Information
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• v.10 no.2
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• pp.244-252
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• 2014

In this study, seismic responses of the offshore wind tower supported by bucket foundation are analyzed in consideration of soil-structure interaction. The program SASSI is used as analyzing tool and an artificial seismic input for soft soil is used as input motion. The H/R ratio of bucket, the stiffness of bucket foundation and the soil stiffness are considered as parameters and its effects are estimated. The responses of structure are obtained at the base and the nacell. As results, the effects of H/R ratio, the stiffness of bucket and the stiffness of site are generally denoted different response tendency at the base and the nacell. However, these whole responses of the base and the nacell are much lager than that of rock site. Therefore, the consideration of this phemomia affect to the response of offshore wind tower with bucket foundation largely.

• Journal of the Korean GEO-environmental Society
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• v.15 no.9
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• pp.47-58
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• 2014

This study explores methods for modeling the foundation-seabed interaction needed for the load analysis of an offshore wind energy system. It comprises the comparison study of foundation design load analyses for NREL 5 MW turbine according to various soil-foundation interaction models by conducting the load analysis with GH-Bladed, analysis software for offshore wind energy systems. Furthermore, the results of the aforementioned load analysis were applied to foundation analysis software called L-Pile to conduct a safety review of the foundation cross-section design. Differences in the cross-section of a monopile foundation were observed based on the results of the fixed model, winkler spring and coupled spring models, and the analysis of design load cases, including DLC 1.3, DLC 6.1a, and DLC 6.2a. Consequently, under all design load conditions, the diameter and thickness of the monopile foundation cross-section were found to be 7 m and 80 mm, respectively, using the fixed and coupled spring models; the results of the analysis conducted using the winkler spring model showed that the diameter and thickness of the monopile foundation cross-section were 5 m and 60 mm, respectively. The study found that the soil-foundation interaction modeling method had a significant impact on the load analysis results, which determined the cross-section of a foundation. Based on this study, it is anticipated that designing an offshore wind energy system foundation taking the above impact into account would reduce the possibility of a conservative or unconservative design of the foundation.