• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.5
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• pp.439-446
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• 2017

The Maritime Safety Act established restrictions for the passage of oil tankers, prohibiting vessesl carrying more than 1,500 kiloliters of oil or 1,500 tons of a hazardous liquid substance. Prohibited vessels that do not satisfy the restrictions are allowed to enter and depart from a nearby port from the outer sea area to minimize the time and distance the oil tanker must navigate in the prohibited area. Therefore, such regulation should not be construed as referring to inshore traffic. In this study, the traffic volume of coastal tankers that do not use the approaching channels for specific sea areas near Yeosu and Gwangyang Port was analyzed, and the cargo loads of these ships were investigated. The results of this study should be used to allow tankers to minimize the time and distance of navigation in prohibited areas. According to the survey, 16 vessels, 51.6 % of the 31 vessels using inshore traffic included in the study, were loaded with more than 1,500 tons of cargo. This is not appropriate according to the legislation for oil tanker passage. Therefore, in this study, sea routes have been proposed that connect with the approaching channels of specific sea areas, from the outer sea areas of restricted passages. Regulations have also been proposed for the entry and departure of oil tankers around Yeosu and Gwangyang Port.

• Journal of Navigation and Port Research
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• v.35 no.10
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• pp.823-827
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• 2011

The present Common Structural Rules for double hull oil tanker is not included the residual strength, which is one of the functional requirements in design part of Goal-based new ship construction standards (GBS). The GBS will be enforced after July 1, 2016. The requirement related residual strength has the goal to build safe ship even if she has the specified damages due to marine accidents including collision and grounding. In order to assess the residual strength based on risk for structural damages according to GBS, tons of nonlinear FE analysis work taking into account various types of damage will be needed. The Smith's method, a kind of simplified method for the strength analysis is very useful for this purpose. In this paper, the residual strength assessments based on ultimate strength using Smith's method were carried out. The objected ship is VLCC with stranding damage in bottom structures. Also, the results were compared with that of nonlinear FE analysis using three cargo hold model.

• Journal of Korea Port Economic Association
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• v.31 no.1
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• pp.37-49
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• 2015

According to outstanding maritime economists from domestic and overseas, shipping lines or ships' enlargement reduce fixed costs, and assist realization of scale of economy of shipping. On the contrary, recent Korean liquidity crisis on the shipping lines (SL) has been focused on the leading companies such as Hanjin Shipping (HJS), Korealines, and STX Pan Ocean. In this respect, this study aims to review Korean SLs' strategies and suggest the optimal solution between the specialization and enlargement. For these purposes, this research adopts slack based measure data envelopment analysis (SBM-DEA) model as a research methodology. As for decision making units (DMUs), SLs which have increased the vessel numbers and belonged to top tier group in year 2013, are selected. The results are comprised with two aspects. Firstly, HJS, KMTC, Korea LNG Trading (KLT), EUKOR, and Sinokor Tanker show the most efficient in regard to constant return to scale (CRS) model. Secondly, HJS, KMTC, KLT, Daerim, Chungang, Sinnokor Tanker, and EUKOR are the most efficient companies in terms of variable return to scale (VRS) model. Lastly, these results could be affected to the management philosophy and can answer the following question. Which is the most optimized SL?s management decision making, enlargement or specialization?

• Journal of Navigation and Port Research
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• v.26 no.4
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• pp.373-381
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• 2002

There has been an interesting trend showing that the number of tankers owned by major oil company has been decreasing since the 1980s, while the number of tankers chartered by them is increasing. So do Korea oil refineries in the period 1990s. Therefore, the following question is raised： Why have oil refinery companies, national and international, been much more dependent upon chartered ships than their owned ships since 1980s\ulcorner This paper tried to answer the above question. In so, doing ten decision-making factors for fleet composition of oil tankers are drawn through literature survey on the research topic with questionnaires and interviews to the four big Korean oil refineries.

• Journal of the Society of Naval Architects of Korea
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• v.28 no.2
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• pp.1-11
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• 1991

A hull form for an Aframax tanker whore form parameters cover the values of $C_B{\simeq}0.8,\;L/B{\simeq}5.5\;and\;B/d{\simeq}3.5$ has been developed by applying a composite stern frameline concept and its excellent performance has been evaluated through a series of model tests at the Korea Research Institute of Ships and Ocean Engineering. The tests showed that this concept was very much promising in the cases of wide breadth and shallow draught vessels and suitably applicable to the stern frameline shape. For the comparison, a hull form developed by Japanese 'H' yard has been selected and the performances of two hull forms were evaluated by model tests and theoretical calculations. The comparison shows that Daewoo hull form requires less effective power by 10% and less delevered power by 5-6% at both full load and ballast conditions. In addition, it is suggested that Hushes method can give better correlationthan Froude method because the full scale resistance extrapolated by Froude method would be very much optimistic in case of the hull form with very low value of form factor.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.6
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• pp.503-513
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• 2016

In order to reduce the green-house gas exhaustion, International Maritime Organization (IMO) has been reinforcing carbon gas regulations. Due to the regulations, a lot of competitions for designing Eco ship in the shipbuilding industry are progressing now. It is faced with the necessity of reducing hull weight by combining automated systems for optimal compartment arrangement with hull structural design. Most researches on optimum structural design method have been consistently in progress and applied to minimize weight and cost of mid-ship section in preliminary ship design stage based on analytical structural analysis method on fixed compartment arrangement. In order to reduce design period and to improve international technical competitiveness by shortening the period of hull structural design and enhancing design accuracy, it has been felt necessity to combine optimized compartment arrangement with optimum design of ship structure based on the international regulations and rules. So in this study, the automated design algorithm for longitudinal members has been developed to combine automated algorithm of compartment arrangement with hull structural design system for oil tanker. The SeaTrust-Hullscan software developed by Korean Register is used to perform ship structural design for mother ship and selected design cases. The effect of weight reduction is verified with comparison of ship weight between mother ship and the cases suggested in this study.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.822-831
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• 2021

Although programs have been developed to evaluate the risk of dragging anchors, it is practically difficult for VTS(vessel traffic service) operators to calculate and evaluate these risks by obtaining input factors from anchored ships. Therefore, in this study, the gross tonnage (GT) that could be easily obtained from the ship by the VTS operators was set as an independent variable, and linear and nonlinear regression analyses were performed using the input factors as the dependent variables. From comparing the fit of the polynomial model (linear) and power series model (nonlinear), the power series model was evaluated to be more suitable for all input factors in the case of container ships and bulk carriers. However, in the case of tanker ships, the power supply model was suitable for the LBP(length between perpendiculars), width, and draft, and the polynomial model was evaluated to be more suitable for the front wind pressure area, weight of the anchor, equipment number, and height of the hawse pipe from the bottom of the ship. In addition, all other dependent variables, except for the front wind pressure area factor of the tanker ship, showed high degrees of fit with a coefficient of determination (R-squared value) of 0.7 or more. Therefore, among the input factors of the dragging anchor risk assessment program, all factors except the external force, seabed quality, water depth, and amount of anchor chain let out are automatically applied by the regression analysis model formula when only the GT of the ship is provided.

• Journal of Korea Port Economic Association
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• v.39 no.2
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• pp.129-141
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• 2023

This study analyzes the dynamic characteristics of daily freight rates of dry bulk and tanker shipping markets and their forecasting accuracy by using the error correction models. In order to calculate the error terms from the co-integrated time series, this study uses the common stochastic trend model (CSTM model) and vector error correction model (VECM model). First, the error correction model using the error term from the CSTM model yields more appropriate results of adjustment speed coefficient than one using the error term from the VECM model. Furthermore, according to the adjusted determination coefficients (adjR²), the error correction model of CSTM-model error term shows more model fitness than that of VECM-model error term. Second, according to the criteria of mean absolute error (MAE) and mean absolute scaled error (MASE) which measure the forecasting accuracy, the results show that the error correction model with CSTM-model error term produces more accurate forecasts than that of VECM-model error term in the 12 cases among the total 15 cases. This study proposes the analysis and forecast tasks 1) using both of the CSTM-model and VECM-model error terms at the same time and 2) incorporating additional data of commodity and energy markets, and 3) differentiating the adjustment speed coefficients based the sign of the error term as the future research topics.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.122-125
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• 2008

Generally, in shipbuilding, large curved block components which have large curvature radius along various directions are used for huge ships such as LPG-vessel and oil tanker ships. Lots of the blocks are manufactured by line heating method which uses a heat source to bend the thick plate materials. The conventional forming process is entirely dependent on the experience of experts because it is done by manual method thus the curvatures and qualities are not uniform even for same part. However, it is hard to adopt the press forming process using die tool sets fur the manufacturing because of the characteristics of the industry that based on the small quantity and variety in the products. In this study, flexible forming technology using numbers of punches is investigated based on the simulation to substitute for the conventional forming method. Thick plate material model was applied to the proposed process to verify the feasibility for hull structure block forming process. The press forming processes were simulated by adopting the explicit-to-implicit sequential solution. Moreover, experiment of the flexible forming process was also conducted and its results were compared with that of simulation.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.1
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• pp.31-38
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• 2008

Tanker oil outflow accident and nitric acid 2000 ton of our country T'aean offing fire etc. vessel sinking and the national treasure 1 good-natured person swunglyey bites to tell the truth the many misfortune occurred in recent times and the numerous casualty occurred. Consequently the righteousness where the preparation and misfortune will occur became the VIP where the preparation and misfortune will occur became the VIP where the information transmission which is quick is important about disaster. Consequently establishes the information transmission system which is quick in the area where the effect of misfortune is worried from observation perceives a disaster construction system development the merger of state radio network with under contributing which minimizes the loss of property and life of the citizen who is caused by with disaster damage boil.