• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.7
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• pp.810-819
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• 2020

Recently, the demand for liquefied gas has been increasing for various reasons, including environmental problems, and as a result, transportation of liquefied gas through a ship is increasing, and several terminals are also being constructed to accommodate it. The size of the terminal to be constructed shall follow the result if the target ship is clearly determined. Otherwise, the size of the vessel that the terminal intends to accept shall be determined, and then, the dimensions of the vessel given in the regulations or standards shall be used. In this regard, it was found that the main dimensions of the proposed vessels are substantially different from those actually operating and the standard for large-sized vessels has not been established in the process of determining the size of the target vessel by using the "Port and Fishing Port Design Standards" and commentary(2017), which recently is most commonly used as port design criteria in order to construct the liquefied gas terminal. Because of these problems, a revision of the standard for the major dimensions of liquefied gas carriers was proposed through an analysis of the current status of ships in service, as there could be many differences between interested parties in determining the size of the target ships and terminals and evaluating the safety of terminals. It is expected that the proposed revision will be used as a more appropriate and realistic criterion for determining the size of ships and terminals in the future and will prevent unnecessary terminal construction costs.

• Journal of Navigation and Port Research
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• v.28 no.7
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• pp.619-627
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• 2004

Introduction of wave model, considered the effect of shoaling, refraction, diffraction, partial reflection, bottom friction, breaking at the coastal waters of complex bathymetry, is a very important factor for most coastal engineering design and disaster prevention problems. As waves move from deeper waters to shallow coastal waters, the fundamental wave parameters will change and the wave energy is redistributed along wave crests due to the depth variation, the presence of islands, coastal protection structures, irregularities of the enclosing shore boundaries, and other geological features. Moreover, waves undergo severe change inside the surf zone where wave breaking occurs and in the regions where reflected waves from coastline and structural boundaries interact with the incident waves. Therefore, the application of mild-slope equation model in this field would help for understanding of wave transformation mechanism where many other models could not deal with up to now. The purpose of this study is to form a extended mild-slope equation wave model and make comparison and analysis on variation of harbor responses in the vicinities of Ulsan Harbor and Ulsan New Port, etc. due to construction of New Port in Ulsan Bay. We also considered the increase of water depth at the entrance channel by dredging work up to 15 meters depth in order to see the dredging effect. Among several model analyses, the nonlinear and breaking wave conditions are showed the most applicable results. This type of trial might be a milestone for port development in macro scale, where the induced impact analysis in the existing port due to the development could be easily neglected.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.08a
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• pp.217-225
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• 2004

Introduction of wave model, considered the effect of shoaling, refraction, diffraction, partial reflection, bottom friction, breaking at the coastal waters of complex bathymetry, is a very important factor for most coastal engineering design and disaster prevention problems. As waves move from deeper waters to shallow coastal waters, the fundamental wave parameters will change and the wave energy is redistributed along wave crests due to the depth variation, the presence of islands, coastal protection structures, irregularities of the enclosing shore boundaries, and other geological features. Moreover, waves undergo severe change inside the surf zone where wave breaking occurs and in the regions where reflected waves from coastline and structural boundaries interact with the incident waves. Therefore, the application of mild-slope equation model in this field would help for understanding of wave transformation mechanism where many other models could not deal with up to now. The purpose of this study is to form a extended mild-slope equation wave model and make comparison and analysis on variation of harbor responses in the vicinities of Ulsan Harbor and Ulsan New Port, etc. due to construction of New Port in Ulsan Bay. This type of trial might be a milestone for port development in macro scale, where the induced impact analysis in the existing port due to the development could be easily neglected.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.211-216
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• 2006

Within the frame of the MERCOSUR (South Common Market), one of the most important goals to achieve by its member states is a better cost effective international cargo transportation system. For this purpose the project of developing a commercial waterway linking the east region of Uruguay with the south of Brazil has been under study for a number of years now. Because of the high costs involved on the development of such waterway, the project has been indefinitely delayed. It is our intention to show an alternative way to reduce the present obstacles by using a budget oriented approach in order to determine the vessel best suited to use on the proposed waterway. So far, every study related to the project has been focused on the amount of work needed to modify the environment in order to accommodate the hardware already available in the region. The conclusions show that the cost of opening and maintaining the required navigation channel is high enough to discourage investment; the added responsibility to take care of any environmental damage incurred during the building and/or operation of the waterway makes searching for a less costly and hazardous option an interesting challenge. The proposed terminal on the Cebollat? River would be located at the heart of the Uruguayan rice growing region. Uruguay exports 90% of its rice production, being Brazil its biggest buyer. Wood chips and clinker are the other types of cargo considered to use the proposed waterway in route to either Brazil or to overseas destinations through the deep water port of Rio Grande. Through the analysis of local data by a Geographical Information System, international regulations regarding inland waterways and shallow draught vessel characteristics, we seek to propose a cost efficient alternative to apply on this particular scenario.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.221-224
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• 2005

According as marine leisure industry has developed and the demand of leisure culture has increased rapidly, a desire about service which supply marine safety and connect marine information is enlarging. We wish tc develop contents of download form that supply geographic information of Electronic Navigational Chart(ENC) in the marine that is digitalized to carrying along terminal of WIPI base and various informations for marine leisure. For this, DB that offer ENC and additional information should be constructed. Also, we need server (CPS; Contents provider Server) that offer required contents. In this paper, we design web retrieval component which store request information to database. When consumer required necessary information through personal mobile device, CPS can inform that. So, we wish to develop web retrieval agent component that parse informations in various World Wide Webs, and store to database.

• Ocean and Polar Research
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• v.43 no.3
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• pp.141-148
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• 2021

Microplastic contamination in waterbodies is a growing source of concern for researchers and other stakeholders. We investigated oxidative stress and toxicity in goldfish (Carassius auratus) in response to exposure to 1-㎛ diameter micro-polystyrene (MP) at concentrations of 0, 10, 100, and 1000 beads/mL (MP 0, MP 10, MP 100, and MP 1000 groups) for 7 d (at day 0, 1, 3, 5, and 7). We analyzed the survival rates; superoxide dismutase (SOD) and catalase (CAT) mRNA expression levels in the liver; SOD and CAT activity in the plasma; caspase-3 mRNA expression in the liver; and the levels of hydrogen peroxide (H₂O₂) in plasma. Terminal transferase dUTP nick end labeling (TUNEL) assays were also conducted to determine apoptosis levels in the liver. All fish in the MP 1000 group died by day 7 and the MP 100 group had a lower survival rate than the MP 10 and MP 0 groups. The mRNA expression as well as SOD, CAT, and caspase-3 activity levels were increased significantly with increases in MP concentration and exposure time. Finally, according to the TUNEL assay, more apoptosis was observed in the MP 1000 group at day 5 than in other groups. In summary, MP concentrations above 100 beads/mL caused death and oxidative stress to goldfish. We conclude that MP can cause oxidative stress and apoptosis in goldfish, which leads to death.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.659-665
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• 2023

The exciter of a ship generator adjusts the magnetic flux through excitation current control to maintain the output terminal voltage constant. The voltage controller inside the exciter typically uses a proportional integral control method. however, the response characteristics determined by the gain and time constant produce unwanted output owing to an inappropriate setting value that can reduce the quality and stability of power within the ship. In this study, a neural network circuit is learned using stable input/output data that can be obtained through the AC4A type exciter model provided by IEEE, and the simulation is performed by replacing the existing proportional integral control type voltage controller with the learned neural network circuit controller. Consequently, overshooting was improved by up to 9.63% compared with that of the previous model, and excellence in stable response characteristics was confirmed.

• Journal of Navigation and Port Research
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• v.45 no.4
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• pp.186-193
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• 2021

To enhance the competitiveness of the Busan Port in accordance with changes in global shipping and port industry trends, the Busan New Port is promoting step-by-step integration and developing a port resource-sharing platform. However, inefficient resource-sharing can cause unnecessary additional costs or impede port productivity, so accurate supply and demand matching of shared resources is required. In this study, the supply and demand of port resources were investigated for employees of Busan New Port and North Port, and port resources that could be ideally shared through IPA(Importance Performance Analysis) were analyzed. As a result of analyzing the equipment in the port, Yard Tractor, Reach Stacker, and Top Handler were the top considerations, and for facilities in the port, berths and aprons, empty container yards, and refrigerated container yards were the most important considerations. As for the data in the port, gate status, equipment specifications, and berth and apron conditions were the top considerations.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.5
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• pp.449-452
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• 2016

This paper presents a simplified analysis on the rotor position detection error in sensorless interior permanent magnet brushless DC motor (BLDCM) drives, wherein terminal voltage sensing based on the back-electromotive force (back-EMF) zero-crossing point detecting circuitry is employed. The effect of a rotor saliency on the back-EMF's zero-crossing point detection is analyzed using the extended EMF-based voltage equation of the interior permanent BLDCM in a stationary reference frame, and thus the overall analysis is considerably simplified compared to the conventional one. Simulation results are provided to verify the effectiveness of the proposed method.

• Journal of Korean Institute of Industrial Engineers
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• v.35 no.1
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• pp.58-72
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• 2009

The main activities of container terminals are to load container freights to vessels, discharge them from vessels, and store them in the storage yard. Container terminals make many operational plans to execute these functions effectively. If the plans do not consider enough the loads of related resources, they may have low actualities. This study discusses the optimal yard planning model which considers various resources, such as the storage yard, yard cranes, internal vehicles, and travel lanes, in container terminals. The model determines the groups and amounts of containers which are stored in each storage block by using the resource profile. The yard planning problem is represented to the multi-commodity minimal cost flow problem and is formulated to the linear programming model. In order to explain the application of the mathematical model, the numerical examples are presented. Additionally, the relationship between the average load ratio and the relocation ratio is discussed.