• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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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.

• 한국해양공학회지
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• 제33권6호
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• pp.495-503
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• 2019

Approximately 90,000 ships are registered in South Korea, and about 80,000 of these ships are used in domestic shipping. Among these, 84% are small ships, such as a fishing vessels that weigh less than 20 tons and are made mostly of an FRP (Fiber Reinforced Plastics). When this fact is taken into account, the greenhouse gas emissions that are released per ton of a composite vessel are sizeable. In this study, the laminated structures of an FRP fishing vessel, many of which currently are being built in Korea, were analyzed by ISO (International Organization for Standardization) and international design rules, and the structures of the hulls are lightweight with optimum glass fiber mass content as determined by the laminate weight minimization algorithm. As a result, it was confirmed that the laminations of the vessels in accordance with the Korean rule could have 6.4% to approximately 11% more design margin compared to the requirements of ISO and other international rules. And the case study of the application of the laminate weight minimization algorithm showed the possibility of reducing the weight of the hull bottom plating by as much as about 19.32% and by as much as about 18.06% in the overall structure.

• 한국해양공학회지
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• 제25권2호
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• pp.113-119
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• 2011

The Korea navy has a vital national interest in maritime security. The national strategy for maritime security focuses on preventing terrorism, crime, and hostile acts in the maritime domain. This requires the development of high speed crafts for maritime security in the South Korea domain. This paper reviews the state of the art on the development of high speed craft internationally, including efforts by the U.S. navy, and analyses the riverine environment to operate high speed crafts in South Korea. This paper makes specific proposals for high speed craft such as their main dimensions, speed, endurance, hull structure material, propulsion system, and general arrangement and 3D shape. This paper was used in the generation of basic resources for future ROC (requirement of capability) of high speed crafts using an engineering methodology.

• 한국해양공학회지
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• 제31권6호
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• pp.379-387
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• 2017

In this study, a pile-guide mooring system (PGMS) was designed for an offshore liquefied natural gas bunkering terminal (LNG-BT), which is an essential infrastructure for large LNG-fuelled ships. The PGMS consisted of guide piles to restrict five motions of the floater, except for heave, as well as a seabed truss structure to support the guide piles and foundation piles to fix the system to the seabed. Singapore port was considered for a case study because it is a highly probable ports for LNG bunkering projects. The wave height, current speed, and wind speed in Singapore port were investigated to calculate the environmental loads acting on the hull and PGMS. A load and resistance factor approach was used for the structural design, and a finite element analysis was performed for design verification. The steel usage of the PGMS was analyzed and compared with the material usage of a gravity-based structure under similar LNG capacity and water depth criteria. This paper also describes the water depth limit and wave conditions of the PGMS based on estimation of the initial investment and the present value profit difference. It suggests a suitable LNG-BT support system for various design conditions.

• 농촌지도와개발
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• 제14권1호
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• pp.171-195
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• 2007

Gyeonggi rice has been placed relatively favorable market position in the domestic rice market. With the superiority of its quality, gyeonggi rice has been well recognized to consumers. The price of gyeonggi rice has placed higher position than that of others. But, gyeonggi rice are facing crisis on the competition by regional brands. Therefore, this study was carried out to find the differentiated marketing strategies on problem related with the product differentiation and brand marketing of gyeonggi rice. In order to find out how much the effort on the product differentiation of gyeonggi rice affects the price and brand recognition, fifty RPCs in gyeonggi province were surveyed. As the results, $22{\sim}23%$ of harvested rice which was gathered into RPC was come out 'obscurity of production origin' when we consider material hull rice in the original production territory by collecting time and channel. With comparing sales weight of gyeonggi rice by the place of shipment, agricultural cooperative channel was the highest by 44.7%. And, wholesaler comes to 17.7%, discount outlet store was 13.9%, large quantity delivery in business was 11.1%, and department store was only 5.2%. Finally, we could consider to adopt the traceability system on gyeonggi rice distribution system from production to consumers' table to get consumers' credibility and compete imported high quality rice.

• 복식
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• 제57권2호
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• pp.143-154
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• 2007

This study's purpose is how express gender image according to sex in editorial fashion photography. This study's objectives are the women's magazine Vogue, Harper's Bazaar and man's magazine GQ, Esquire published 2000-2005 within the country. The photography was classified with established a standard based on the precede studies. The photo is classified Gender image according to dress and its ornaments, model character and atmosphere by Sex Expression of femininity woman has exposure of body parts and emphasizing thin eyebrows and red lips, soft and mild image, modest and static pose. Man expressed femininity used ladylike color and pattern, erotic exposure of body and long hair style. Commonly emphasizing red lips, natural background of flower plant, S-line. For expression of masculinity man and woman are used masculinity item, short hair-style and thick eyebrows. And also emphasize square like chin and shoulder. Specially, woman used direct silhouette to conceal soft body curved line. The expressions of androgynous woman and man are colorful dress and make-up. Woman emphasized male face to show and man expressed soft image through hull of abundant material of fur. All two sex selected method that conceal body curved line and face to express sexless. Hiding characteristics of body and face make indistinct of sex. The gender is affected by atmosphere such as model and illumination background as much as clothes because of the editorial fashion photography.

• 한국소음진동공학회논문집
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• 제23권8호
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• pp.770-776
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• 2013

Fluid-borne noise produced by seawater circulating pumps propagates through the seawater connected pipes and radiates from the hull opening of a ship. This noise causes the increases of underwater radiated noise and self noise of ship. To reduce the noise propagation through the seawater connected pipes, absorptive silencer must be needed. In this paper, theoretical model to analyze the transmission loss of absorptive silencer was presented and the design parameters of absorptive silencer were verified. Theoretical calculations were performed according to a thickness, a length, an internal pressure and mechanical properties of its absorptive material in order to analyze the characteristics of absorptive silencer. From the theoretical calculation results, the absorptive silencer was manufactured and transmission loss was measured in the test facilities. The results of theory and measurement are compared and discussed.

• 대한조선학회논문집
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• 제48권2호
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• pp.178-182
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• 2011

Generally in order to reduce the steel weight of stiffened plate, stiffener spaces tend to be narrow and the plate gets thin. However, it will involve more fabrication cost because it can lead to the increase of welding length and the number of structural members. In the yard, the design which is able to reduce the total fabrication cost is needed, although it requires more steel weight. The purpose of this study is to find optimum stiffener spaces to minimize the fabrication cost for the cargo tank of LPG Carriers. Global optimization methods such as ES(Evolution Strategy) and GA(Genetic Algorithm) are introduced to find a global optimum solution and the sum of steel material cost and labor cost is selected as main objective function. Convergence degree of both methods in according to the size of searching population is examined and an efficient size is investigated. In order to verify the necessity of the optimum design based on the cost, minimum weight design and minimum cost design are carried out.

• 대한조선학회논문집
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• 제46권3호
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• pp.290-302
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• 2009

Pipe system widely used in a ship is usually attached to the hull of a ship, and its vibration lead to structure-borne noise. Rubber mount is usually used as a vibration isolator of a pipe in a ship. In this paper, the effects of several factors, besides the stiffness and damping of the rubber mount, on vibration-isolating performance are taken into consideration. The parameters considered in this paper are hardness of the rubber material, painting on the rubber and deformation from clamping. Through the results of parametric study, the effective specifications of rubber mount are suggested to improve vibration-isolating performance. The performance under fluid flowing condition is calculated numerically and verified experimentally.

• 대한조선학회논문집
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• 제47권2호
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• pp.210-224
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• 2010

The aim of the present study is to investigate the buckling strength of plates and stiffened panels with opening under transverse thrust and shear actions. It is observed that the existing design formulation for critical-buckling strength of plates are not valid for perforated plates, because the current design formulation trends can significantly overestimate or underestimate the load-carrying capacity of plates when plates have large opening and/or are thick. A series of eigen value and elastic.plastic large deflection finite element analyses are carried out with varying the aspect ratio of plate, the opening size and location on plate until and after the ultimate strength is reached. Based on the results obtained from the present study, closed-form design formulations for the elastic buckling strength of plates and stiffened panels with opening are derived. The derived design formulations are considered plasticity correction of the material and verified by experimental tests and results of nonlinear finite element computations.