• Journal of Welding and Joining
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• v.34 no.2
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• pp.22-29
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• 2016

Recently, Application of composite materials are increased in transport area for weight reduction. Also, Related technical developments have been implemented actively at domestic and abroad. In particular, The carbon fiber has high strength and ultra light property higher than stainless steel, aluminum, GFRP as Eco-friendly material. Carbon fiber contribute to improving the environmental effect such as fuel saving, expansion of loadage, reducing the exhaustion of carbon dioxide through the weight reduction of transport area. In addition, The carbon fiber is applied to the ship in the area of race yacht, luxury cruise boat as weight reduction and high added-value materials, but there is limited application for general boat because price of carbon fiber is very expensive. For the weight reduction of general boat hull, being used as structure materials, glass fiber and carbon fiber are applied to hull with form of hybrid composite materials, but application of domestic and research for development are incomlete. In this study, An evaluations of mechanical strength property and fatigue strength are performed on composite materials by hybrid weaving of glass fiber and carbon fiber and composite materials forming method by hybrid forming.

• Journal of Ocean Engineering and Technology
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• v.25 no.5
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• pp.27-32
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• 2011

Recently, a ship-shaped barge has been developed to improve the resistance performance, as well as course-keeping capability. However, the stern of the barge is still similar to a box shape, and the vortex generated at the side of the barge creates drag and yaw instability. In order to solve this problem, stern skegs are normally used. The present paper deals with the correlation between the size of the stern skegs and the barge dimensions and hull coefficient. A stern skeg was designed to prevent yaw instability and minimize any additional resistance. The resistance test and course keeping test were performed in the towing tank at Pusan National University. To determine the correlation parameters between the designed stern skeg size and barge dimensions, a parametric study was also performed. Based on the experimental data from five barges, the optimum skeg dimensions were successfully derived. It is expected that the validation of the present study will be carried out by further experiments and computational comparisons in the near future.

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.129-130
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• 2017

This paper suggests study of basic structure design and structural analysis for the twin car-ferries. The rules and methodology for the analysis of strength of medium and small high speed vessels with a length of more than 50m and a width / ratio of more than 12, such as car-ferries, have not been clarified yet. Therefore, in this paper, the scantling of the members is based on the Korea Classification standards, and the car-ferries standards were additionally applied to verify the structural strength of the design. The results of this study are expected to be useful as basic data related to structural design and structural analysis of high speed twin car-ferries.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.6
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• pp.523-531
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• 2019

The low birthrate and the need for national defense reform in Korea drive the Navy to develop efficient human resource planning such as a manpower forecasting model. However, to our knowledge, there is no study exploring the manpower forecasting model for naval ships in Korea. The purpose of this paper is to develop a model for forecasting manpower demand in naval ships. Data for analyses were drawn from 19 ships in the Korean Navy. Results indicate that mission type is significantly related to the number of manpower. Specifically, battleships need the more manpower than the battle support ships. The results also showed that the weight of hull structure-engine and the weight of the weapons system significantly increased the number of manpower. However, the weight of the combat system was not significant. In addition, whereas the automation level of hull structure-engine and the automation level of weapon system was found to be negatively related to the number of manpower, the automation level of combat system was positively related to it. The model developed here contributes to an advanced human resource planning of the Korean Navy. Implications, limitations, and directions for future research are discussed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.10a
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• pp.241-242
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• 2009

There are marry ships and marine structures and also has marry differences on according to the shape and the interval of hulls to the purpose. the multi-submerged body needs appropriate distance between the hulls because of the optimum hull form. thus, through this paper, the flow characteristics behind the multi-submerged body according os the distance ration between the hulls and various angles of attack was conducted.

• Journal of Navigation and Port Research
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• v.44 no.3
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• pp.151-157
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• 2020

Harmful aquatic organisms introduced by ship movement cause marine ecosystem disturbances and are in the form of ballastwater and biofouling. Harmful marine life from ballastwater has been considerably reduced because mandatory treatment on all vessels is required to install onboard vessels. However, there remains risk of migration because biofouling is recommended to countries for management through the IMO guidelines. In particular, biofouling management has recently attracted attention for achieving IMO GHG reduction targets because it contributes to energy efficiency, as well as there are reasons for marine ecosystem protection. In recent years, increasing international consensus on the need for biofouling management is likely to lead to enforcement regulations. Thus, this study suggests the management method of hull attachment organisms in Korea, focusing on the cases of foreign countries that have regulated hull attachment organisms.

• Bulletin of the Society of Naval Architects of Korea
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• v.11 no.1
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• pp.9-16
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• 1974

To contribute towards more accurate estimation of the virtual inertia coefficient for the horizontal vibration of ships, three dimensional correction factor $J_H$ for the added mass of finitely long elliptic prismatic bars in horizontal vibration in a free surface of an ideal fluid are calculated. In the problem formulation Dr. T. Kumai's quasi-finite length concept[1,11,12] is employed. Now that, in Dr. Kumai's work[1] for the horizontal vibration the mathematical model was a circular cylinder, the principal aim of the authors' work is to investigate the influence of the beam-draft ratio B/T on $J_H$. The numerical results of this work are shown in Fig.3 graphically, from which we may recognize that the influence of B/T on $J_H$ is remarkable as much as that of the length-draft ratio L/T(refer to Fig.1 also). In Fig.3 the curves for B/T=2.00 are of those based on Dr. Kumai's result[1]. On the other hand, the experimental data obtained by Burril et al.[9] for the horizontal vibration of finitely long prismatic bars of various cross-section shapes are compared with the theoretical added mass coefficients defined by combination of the authors' $J_H$ from Fig.3 and two dimensional coefficients $C_H$ obtained by Lewis form approximation for the corresponding sections. They are in reasonable correspondence with each other as shown in Fig.2. Finally, considering that the longitudinal profile of full-form ship's hull is well resembled to that of an elliptic cylinder and that the influences of other factors such as the sectional area coefficient and the shape of section contour itself can be well merged in the two dimensional added mass coefficient, the authors recommend that the data given in Fig.3 may be successfully adopted for the three dimensional correction factor the added mass in the horizontal vibration of hull-form ships.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.6
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• pp.447-455
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• 2016

Precise propulsion shafting alignment of ships is very important to prevent damage of its support bearings due to excessive reaction forces caused by hull deflection, forces acted on propeller and crankshaft, and so forth. In this paper, a new iterative shafting alignment calculation procedure considering the interaction between shaft deflection and oil film pressure of Sterntube Journal Bearing (SJB) bush with single or multiple slopes is proposed. The procedure is based on a pressure analysis to evaluate distributed equivalent support stiffness of SJB by solving Reynolds equation and a deflection analysis of shafting system by a finite element method based on Timoshenko beam theory. SJB is approximated with multi-point biaxial elastic supports equally distributed to its length. Their initial stiffness values are estimated from dynamic reaction force calculated by assuming SJB as single rigid support. Then, the shaft deflection and the support stiffness of SJB are sequentially and iteratively calculated by applying a criteria on deflection variation between sequential calculation results. To demonstrate validity and applicability of the proposed procedure for optimal slope design of SJB, numerical analysis results for a shafting system are described.

• Journal of the Korean Society of Systems Engineering
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• v.18 no.2
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• pp.108-116
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• 2022

Accurately predicting wartime resources requirements and preparing war supplies in peacetime is an important task that can determine the outcome of the war by guaranteeing the duration of the operation. The wartime warship damage rate is a measure of estimating the battle damage of our warships in the process of performing battles to achieve the war goal. In the previously studied wartime warship damage rate estimation method, when damage occurs, long-term repair is required due to the complexity and specificity of the ship structure. Only the case of a complete defeat at the level of sinking was defined as a damage, and even if it was impossible to perform a maritime operation mission, it was not estimated as a damage if the level of sinking was not reached. Therefore, in order to improve the reliability of the wartime warship damage rate, the equipment damage assessment level can be estimated based on the warhead weight of the threat weapon system, the vulnerability rate of the warship's equipment, and the warship's hull. In the future, it is expected that the estimation methodology proposed in this study will be used as a simulation logic when developing a model for analyzing the wartime resources requirements for the warship's equipment and hull.

• Korea Trade Review
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• v.45 no.6
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• pp.157-179
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• 2020

This study presented the results of meta-analysis through topic modeling among the papers published in the Journal of the International Trade Association for the purpose of presenting academic research trends in the field of trade insurance and future research directions. Among the total 2,010 papers included in the Journal of the Korea International Trade Association, the analyzed paper covers the subject of trade-related insurance. According to detailed topics, 33 marine insurance (42.31%), 16 export insurance (20.51%), 11 hull insurance (14.10%), and 18 others (23.08%), and 4 other products liability insurance. According to the empirical analysis results, Topic 1 was classified as marine insurance, airworthiness, notice obligation, and collateral, and Topic 2 was derived as a representative topic for loading insurance, emergency risk, and immunity as export insurance. And Topic 3 was classified as vessel, sinking and container in relation to ship insurance, and Topic 4 was analyzed as an important topic such as manufacture and British marine insurance. Through the analysis results, we selected the representative topic used for the trade insurance topic and looked at the status of major research. Trade insurance is an area that requires the development of more theoretical and practical research subjects as an optimal risk management means in international trade transactions. To this end, first, support from the Korea International Trade Association is needed to establish a continuous research subject sharing system for the development of research subjects in the field of trade insurance. Second, academic journal operation management must be continuously managed in which academic research papers can be submitted and published.