• Journal of Navigation and Port Research
• /
• v.46 no.6
• /
• pp.576-584
• /
• 2022

AIS is widely utilized in vessel traffic services for marine traffic safety. In 2021, Korea deployed the high-speed maritime wireless communication system (LTE-Maritime) on the sea following IMO's proposal for the introduction of e-Navigation. In this paper, vessel trajectory data from AIS and LTE-Maritime were used for vessel trajectory prediction to compare and analyze the two systems. The results show that the trajectory prediction error of LTE-Maritime was smaller than that of AIS due to the granular and uniform data provided by LTE-Maritime. Additionally, it was revealed that time interval is the most important factor influencing the errors in trajectory prediction, with the prediction error of LTE-Maritime growing at a slower rate of 17% than AIS. This research contributes to the literature by quantitatively comparing AIS and LTE-Maritime systems for the first time.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.423-423
• /
• 2023

습지 생태계는 탄소저장고, 대기 온·습도 조절 등의 기능을 수행하는 만큼 면밀한 관리가 요구된다. 습지의 규모와 생태계는 밀접한 연관성을 가지므로 그 규모를 우선적으로 파악할 필요가 있으며, 이를 위해 지표면의 상태를 산지, 습지, 수역 등의 항목으로 구분한 토지피복지도가 고려될 수 있다. 현재, 환경부에서 운영 중인 환경공간정보서비스(https://egis.me.go.kr/)에서는 각각 30 m, 5 m, 1 m의 공간 해상도와 7, 22, 41가지 분류 항목을 갖는 대분류, 중분류, 세분류로 구분된 토지피복지도를 제공하며 이러한 자료들은 모두 1년 이상의 시간 해상도를 갖는다. 습지의 경우, 계절에 따른 환경 변화로 인한 규모의 변동성이 크게 나타날 수 있기 때문에 1년 이하의 시간 해상도를 갖는 고품질 토지피복 분류 정보가 요구된다. 따라서 본 연구에서는 기존 자료의 낮은 시간 해상도 보완을 목표로, 1개월과 30 m의 시·공간 해상도를 갖는 토지피복지도를 구축하기 위한 방법론을 제안하고자 한다. 이를 위해 Landsat-8 등과 같은 다양한 인공위성 자료를 수집하고, Support Vector Machine 등과 같은 머신러닝 기법을 적용하였다. 최종적으로 습지보전법에서 지정한 습지보호지역 중 내륙습지 26개소를 대상으로, 본 연구로부터 산출된 토지피복지도를 기존 환경공간정보서비스 내 대분류 토지피복지도와 비교·평가하였다.

• Journal of Navigation and Port Research
• /
• v.47 no.4
• /
• pp.212-219
• /
• 2023

Vessel Traffic Service (VTS) area presents a complex traffic pattern due to ships entering or leaving the port to utilize port facilities, as well as ships passing through the coastal area. To ensure safe and efficient management of maritime traffic, VTS operators continuously monitor and control vessels in real time. However, during periods of high traffic congestion, the workload of VTS operators increases, which can result in delayed or inadequate VTS services. Therefore, it would be beneficial to predict traffic congestion and congested areas to enable more efficient traffic control. Currently, such prediction relies on the experience of VTS operators. In this paper, we defined vessel traffic congestion from the perspective of a VTS operator. We proposed a method to generate traffic networks using historical navigational data and predict traffic congestion and congested areas. Experiments were performed to compare prediction results with real maritime data (Daesan port VTS) and examine whether the proposed method could support VTS operators.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.35 no.2
• /
• pp.109-117
• /
• 2022

There has been an increasing number of studies on photovoltaic energy generation system in an offshore site with the largest energy generation efficiency, as increasing the researches and developments of renewable energies for use of offshore space and resources to replace existing fossil fuels and resolve environmental challenges. For installation and operation of floating photovoltaic systems in an offshore site with harsher environmental conditions, a stiffness of structural members comprising the total system must be reinforced to inland water spaces as dams, reservoirs etc., which have relatively weak condition. However, there are various limitations for the reinforcement of structural stiffness of the system, including producible size, total mass of the system, economic efficiency, etc. Thus, in this study, a floating breakwater is considered for reducing wave loads on the system and minimizing the reinforcement of the structural members. Wave reduction performances of floating breakwaters are evaluated, considering size and distance to the system. The wave loads on the system are evaluated using the higher-order boundary element method (HOBEM), considering the multi-body effect of buoys. Stresses on structural members are assessed by coupled analyses using the finite element method (FEM), considering the wave loads and hydrodynamic characteristics. As the maximum stresses on each of the cases are reviewed and compared, the effect of floating breakwater for floating photovoltaic system is checked, and it is confirmed that the size of breakwater has a significant effect on structural responses of the system.

• Journal of the Society of Disaster Information
• /
• v.13 no.3
• /
• pp.305-312
• /
• 2017

In our society, the advanced, advanced, and information industries have continued to grow and now live in the era of the fourth industrial revolution. As the industry develops, the load of the users has also increased so much that it is deepened by the energy shortage phenomenon and the construction of additional energy facilities is required. Therefore, energy plant construction work is being actively carried out in the coastal area. In particular, it is common to build a plant in the ground by filling the coast with soil in other regions, reflecting the fact that Korea is lacking in the country when constructing power plants, gas and petrochemical plants. Current domestic grounding designs are designed or constructed to suit only the use of grounding resistors based on the electrical equipment design technical standards. However, in the case of a plant facility constructed in the untested buried soil, when the lightning current and the abnormal current are inputted, the facility operator or the user due to the elevation of the ground potential is seriously exposed to the risk of electric shock disaster. In this paper, we analyze the ground resistivity of the landfilled soil and use a computer program (CDEGS) based on KS C IEC 61936-1, We analyze the contact voltage and stratification voltage and propose a grounding design optimized for plant installation.

• Journal of Korean Society of Steel Construction
• /
• v.29 no.1
• /
• pp.89-98
• /
• 2017

The offshore plant structure has been transported to the site by barge because it is hard to manufacture in site. When the structure was transported on the sea, offshore plant structures and connection were experienced repetitive submarine load. For this reason, it was known for that the axial force of high-strength bolted connection was declined. Therefore, in this study, high-strength bolted connection was evaluated the shear fatigue performance under longtime fatigue load during marine transport. The experimental variables were selected intial axial force, surface type, and bolt type because they ar important factors in the change of axial force of bolts. As a experimental results of considering various variables, the variation of axial force showed within 1%. Therefore, the high-strength bolted connection was verified structural safety under longtime fatigue load.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2013.10a
• /
• pp.239-241
• /
• 2013

육상의 U-health서비스와 달리 해상이라는 특수한 지리적 요건으로 인해 사용 가능한 통신기술이 제한적이며, 선박이라는 특수한 공간에서 발생하는 진동과 소음 등 환경적 요소와 의사 및 의료팀의 부재에 따른 의료지식이 현저히 부족한 의료 관리자 및 일반인이 쉽게 시스템을 사용가능하도록 사용성을 고려하여 해상의 선박 및 플랜트 등에서 원격으로 의료서비스 지원이 가능하도록 해양환경에 최적화된 원격의료시스템을 개발하였다.

• Journal of Navigation and Port Research
• /
• v.38 no.2
• /
• pp.163-170
• /
• 2014

Domestic offshore business is oriented toward building drill-ships, FPSOs(Floating Production Storage and Off loading). But the equipments needed for offshore platforms are not so developed in Korea because the equipments can not be verified in Korean territory where the offshore platforms are not stationed. This study aims at finding some methods on entering into OSI for the maintenance and disassembly of fixed offshore platforms. Slack model is adopted to find out how slack assets could play a role in penetrating foreign markets. Firstly, entry into the South East Asian market is recommended. Secondly, forming a consortium is suggested by which taking part in offshore market can be easier. Finally, strategic plans for obtaining the technology for ship building equipments are needed as well as government support.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2019.05a
• /
• pp.10-11
• /
• 2019

해상교통 환경은 항해사, 관제사, 자선, 타선 등의 복합적 상호작용과 관계에 의해서 형성되지만 그동안의 해상교통 분석은 과거 항적 데이터의 통계분석이나 선박운항 시뮬레이터를 이용한 자선의 운항특성을 분석하는 것에 국한되어 왔다. 복잡함 속에서도 교통흐름과 특성을 나타내는 교통 환경을 사실적으로 모사하기 위해서는 교통 환경을 구성하는 각 요소에 대한 모델링 및 시뮬레이션이 사실적으로 이루어지고 요소간의 상호작용이 재현될 수 있어야 한다. 이를 위해서 본 논문에서는 에이전트 기반의 시뮬레이션 기술을 분석하고 적용 방안을 연구하였다.

• Plant Journal
• /
• v.9 no.3
• /
• pp.38-42
• /
• 2013

Submarine gas fields have focused because of the increasing fuel cost, the environmental regulations, and the safety & NIMBY problems. LNG-FPSO which is available for acid gas removal, recovery of the condensate & LPG and Liquefaction in topside process is one of high technology offshore structures. On the other hands, it is necessary to verify the pre-treatment efficiency by the ship motion and to apply to the design for LNG-FPSO. This study is to develop the pre-treatment technology for LNG-FPSO as taking account to the process efficiency by ship motion effects and the area optimization. Based on the simulation results, it founds that hybrid process shows the low circulate rate, the low heat duty and the small size of column dimensions compared to typical amine process. It will be verified the process efficiency in the various conditions by sea states as performing the 6-DOF motion test and CFD simulation.