• Journal of Ocean Engineering and Technology
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• v.14 no.2
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• pp.117-120
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• 2000

In the Step of preliminary ship design a designer should decide a economic ship. The economic ship has the least building cost to a annual freight amount satisfying a given design condition That is RFR is minimum among alternatives.

• Bulletin of the Society of Naval Architects of Korea
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• v.21 no.4
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• pp.1-9
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• 1984

This study is concerned with the economic aspects of $125,000m^3$ class LNG carriers with different propulsion plant such as conventional steam turbine and slow speed diesel engine with reliquefaction plant. The ship's speed and L/B ratio were optimized with criterion of required freight rate(RFR) by using the PROCAL computer program package. In order to investigate the effect of fuel oil price, round trip distance and boil-off rate on the RFR and the optimum speed, sensitivity analysis were also performed.

• Journal of the Korean Institute of Navigation
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• v.16 no.2
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• pp.1-19
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• 1992

A Study for the relation between design parameters in conceptual stage and freight cost in operation of ocean-going bulk carrier was presented by economic criterial. Ship design procedure was followed to traditional method and programmed. The measure of merit is the Required Freight Rate(RFR). Parametric method used insteady of optimization technique due to easy to illustrate the results. Calculation results to the relation ship dimension, speed and operating cost in this paper show the influence of oil price is very important. Particularly, when oil price estimated as go up, owner choose a ship which lengh is long , breadth/draft is near 2.0 and speed is low. This program is useful for shipyard, consultant officer and owner all together.

• Journal of Navigation and Port Research
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• v.29 no.6 s.102
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• pp.529-536
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• 2005

Recently the building of ultra large container ship are discussed among ship building companies and ship operating company who have a tendency to pursue the advantage of large scale of economy. These tendency will be continued for the time being, if ship-building skill and economical efficiency are available. As the enlargement of container ship size becomes hot issues in ship-building markets, the needs for re-arrangement of accommodation house in large container ship are proposed carefully in some researches. This study examined economical efficiency of re-arrangement of accommodation house in ultra large container ship. The separation between accommodation and engine room is proposed through out drawing works in initial design stage and we examined the merits and demerits of the separation in the view of economical efficiency. The RFR(Required Freight Rate) is considered as the objective function to evaluate the re-designed vessel. The economical benefits are analyzed in the view of ship operator and shipyard respectively.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.325-332
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• 2005

As ship builder companies have a tendency to pursuit the effect of scale economy, recently the ultra-large sized container ship is discussed very actively among them. It is expected that these situation will be continued for the time being. The need of accommodation re-arrangement is carefully proposed according to the tendency of ultra-large sized ship. In this paper, accommodation re-arrangement of ultra-large container ship is examined in the view of economy. We proposed separation of engine room and accommodation part through review and supplementaition of drawing generation in intial design stage. Also we investigated its merits and demerits to find out whether it can be realized or not in the view of economical efficiency. The RFR(Required Freight Rate) is considered as the objective function to evaluate the re-designed vessel. The economical benefits for increasing the number of TEU(Twenty-foot Equivalent Units)'s and the re-arranged space are analyzed in the view of ship owner and shipyards respectively.

• International Journal of Ocean System Engineering
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• v.2 no.4
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• pp.233-238
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• 2012

In this study, we carried out a precedent investigation for an ultra-large container ship, which is expected to be a higher value-added vessel. We studied a preliminary optimized design technique for estimating the principal dimensions of an ultra-large container ship. Above all, we have developed optimized dimension estimation models to reduce the building costs and weight, using previous container ships in shipbuilding yards. We also applied a generalized estimation model to estimate the shipping service costs. A Genetic Algorithm, which utilized the RFR (required freight rate) of a container ship as a fitness value, was used in the optimization technique. We could handle uncertainties in the shipping service environment using a Monte-Carlo simulation. We used several processes to verify the estimated dimensions of an ultra-large container ship. We roughly determined the general arrangement of an ultra-large container ship up to 1500 TEU, the capacity check of loading containers, the weight estimation, and so on. Through these processes, we evaluated the possibility for the practical application of the preliminary design model.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.2
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• pp.10-21
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• 1995

In this paper, main particulars of a ship are optimized by the multiobjective optimization method which can offer more information to designer. To analyze the effect of a ship building cost and operating cost in the optimum design of a ship, the multiobjective optimization is performed with objective functions of building and operating costs. And Required Freight Rate(RFR) is also calculated as dependent variable. The design model was developed for the Liquefied Natural Gas(LNG) carrier with longer operating distance. The LNG carrier has some characteristics such as higher speed and building cost in comparison with other commercial ships.

• Bulletin of the Society of Naval Architects of Korea
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• v.21 no.2
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• pp.1-7
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• 1984

This paper is concerned with an optimum design study of containerships in preliminary stage by applying economic criteria. The Net Present Value Index (NPVI) and the Required Freight Rate(RFR) are used as measures of merit. Hooke & Jeeves direct search method and External Penalty Function method of Sequential Unconstrained Minimization Techniques(SUMT) are used for solving constrained nonlinear optimization problem. Sensitivity analysis is carried out to investigate the effect on the optimum solution due to change of values in some parameters such as crane capacity, load factor, oil price, ship speed and the ratio between loaded FEU and TEU.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.4
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• pp.591-598
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• 2002

In the ship structural design, the material cost of hull weight and the overall cost of construction processes should be minimized considering safety and reliability. In the past, minimum weight design has been mainly focused on reducing material cost and increasing dead weight reflect the interests of a ship's owner. But, in the past experience, the minimum weight design has been inevitably lead to increasing the construction cost. Therefore, it is necessary that the designer of ship structure should consider both structural weight and construction cost. In this point of view, multi-objective optimization technique is proposed to design the ship structure in this study. According to the proposed algorithm, the results of optimization were compared to the structural design of actual VLCC(Very Large Crude Oil Carrier). Objective functions were weight cost and construction cost of VLCC, and ES(Evolution Strategies), one of the stochastic search methods, was used as an optimization solver. For the scantlings of members and the estimations of objectives, classification rule was adopted for the longitudinal members, and the direct calculation method, GSDM(Generalized Slope Deflection Method), lot the transverse members. To choose the most economical design point among the results of Pareto optimal set, RFR(Required Freight Rate) was evaluated for each Pareto point, and compared to actual ship.