• Journal of the Society of Naval Architects of Korea
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• v.39 no.2
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• pp.28-33
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• 2002

The characteristics of hull-pieces are large quantity, comparatively large piece-size, and different each shape. For the more, in the forming process(including Line-Heating Process) of curved hull pieces, shape checking processes including initial shape measurement and forming shape measurement of the each pieces are needed to achieve a given accuracy. So, the forming process of large curved hull pieces needs efficient measurement and comparison technique to check the shape and ensure the forming-accuracy In this paper, we try to construct integrated S/W, H/W system for efficient measurement and comparison of large curved hull pieces, which can apply to above forming environment.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.18-18
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• 2010

최근에 건조되는 선박이나 구조물들은 점차 대형화 되어가고, 이에 사용되는 판재들은 점차 고강도 극후판재화 되어가고 있다. 극후판재의 용접성을 향상시키기 위해서는 대입열 용접이 주로 적용되고 있는 실정인데, 30 mmt 이상의 후판을 1 pass로 용접하기 위해서는 EGW(Electro-gas welding) 기법을 사용한다. 대입열 용접은 용접입열(heat input)이 매우 높아 용착금속과 열영향부의 냉각속도가 매우 느려 용접열영향부에서 특히 fusion line 근처의 열영향부는 결정립 조대화 및 취약한 미세조직을 형성함으로서 저온인성을 크게 저하시키고, 연화 현상(softening effect)을 발생시켜 강도가 저하되는 문제점이 주로 발생하였다. 하지만 이런 문제점을 해결하기 위해 대입열용접에 사용된는 강재의 미세조직을 제어하여 AlN, TiN, $TiO_2$ 등의 석출물을 이용한 용접열영향부의 저온인성을 향상시켰다. 이러한 문제점이 발생하는 대입열용접에서 저온인성 시험은 주로 fuison line + 1, 2mm에서 수행한다. 하지만 대입열 용접시 용착금속의 냉각속도도 매우 느리기 때문에 용착금속의 위치에 따라 저온 인성 특성이 다르게 나타날 수 있다. 본 연구에서는 EGW 용착금속의 위치에 따른 저온인성 특성을 평가하기 위해 EH-36N, 40mmt 판재를 사용하여 1pole EG 용접 하였다. 용착금속의 저온인성 특성을 평가하기위해 충격 시편의 노치 위치가 fusion line - 2mm와 용접부 중앙을 기준으로 4곳을 선정하여 충격시험을 수행하였다. 또한 용착금속의 경도 분포를 알아보기 위해 micro vickers hardness tester(mitutoyo UR-501)을 사용해 hardness mapping 시험을 하였다. 용착금속의 저온인성은 미세조직과, 산소량에 따라 변화 할 수 있기 때문에 용착금속 위치를 달리하여 미세조직과 산소량도 각각 분석하였다. 용착금속의 저온인성을 향상시킬 수 있는 침상형페라이트와 비금속개재물의 상관관계에 관해 검토 하였다.

• Journal of Navigation and Port Research
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• v.31 no.5 s.121
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• pp.377-383
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• 2007

The number of calling ports has been decreased and the degree of inter- and intra-port competition has been increased, which is caused by the market trends that shipping liners have and operate their own terminals, strategic M & A frequency occurs among shipping liners, and container vessel size is increasing. The trends also cause shipping liners to change the evaluation factors for decision to call a particular port such as port preference, potential for growth, port competitiveness, etc. Since the decision of liners greatly influences the policies for port and terminal development, it is worth having interest in the evaluation factors. Therefore, this work intended to evaluate 8 major ports (Port of Singapore, Hong Kong, Shanghai, Busan, Rotterdam, Kaoshing, and Tokyo) with regard to liners' evaluation factors (calling port preference, potential for growth and port competitiveness) and to classify ports by similarity of evaluation factors with the methodologies of ANOVA analysis and Duncan test. The result shows implication for liners' viewpoint to evaluate major ports in the world.

• Journal of Korea Port Economic Association
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• v.26 no.1
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• pp.234-258
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• 2010

This research attempts to explore the competitive advantage of the Busan New Port based on the comparative analysis against the major ports. The competitive environment of the global shipping business poses a variety of challenges for the port authorities. Pursuing the hub position in the Northeast Asia, Busan new port needs an in-depth competitive analysis against the major ports in Singapore and China. This research proposes the strategies to exploit the locational advantage of the port while upgrading the operational efficiency. The recent development of the information technology suggests a viable solution for the Busan port.

• Journal of Navigation and Port Research
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• v.34 no.3
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• pp.221-228
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• 2010

As container traffic is increasing, the introduction of mega-vessel has had a significant impact on the ports and terminals business. This movement of container shipping has led to intensely competitive environment among ports, so substantial pressures to develop new container ports or to expand existing ones, have been grown. However, it requires a huge investment, especially cost and time, to overcome environmental, geographical and financial restrictions generated from developing a port. This study addressed the Mobile Harbor, the new concept of marine logistics system as an alternative strategy. We performed an economic analysis on the introduction of the Mobile Harbor in coastal transport sector and also a sensitivity analysis to examine the effects of changing factors related on the economic evaluation. We have examined the value and application of Mobile Harbor as a preliminary study, which may contribute to further studies on the Mobile Harbor.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.243-248
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• 2006

Recently, China opened Yangshan port and provides a variety of benefits for shipping companies. Japan plans to reduce logistics costs and improve efficiency through the established 'super major ports' project. According to the 'hub and spokes' system, the number of direct calls toward North-Chinese ports are increasing. This changing environment has negative effects on the amount of transshipment cargos in Korean ports. In order to make a hub port of a domestic port, it is necessary to develop northeast Asian Feeder networks. Therefore, this paper analyzes the structure of northeast Asian feeder networks through the case study of European feeder networks strategy. Finally, we suggests the plans to reinforce feeder networks, which are strategic terminal operation, strategic alliances between shipping companies and port co-operation, for win-win strategy in the competitive northeast Asian market.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.1004-1010
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• 2021

Ship-floating object accidents can lead not only to a delay in ship's operations, but also to large scale casualties. Hence, preventive measures are required to avoid them. This study analyzed the spatiotemporal aspects of such collisions based on the data on ship-floating object accidents in sea areas in the last five years, including the collisions in South Korea's territorial seas and exclusive economic zones. We also provide basic data for related research fields. To understand the distribution of the relative density of accidents involving floating objects, the sea area under analysis was visualized as a grid and a two-dimensional histogram was generated. A multinomial logistic regression model was used to analyze the effect of variables such as time of day and season on the collisions. The spatial analysis revealed that the collision density was highest for the areas extending from Geoje Island to Tongyeong, including Jinhae Bay, and that it was high near Jeongok Port in the West Sea and the northern part of Jeju Island. The temporal analysis revealed that the collisions occurred most frequently during the day (71.4%) and in autumn. Furthermore, the likelihood of collision with floating objects was much higher for professional fishing vessels, leisure vessels, and recreational fishing vessels than for cargo vessels during the day and in autumn. The results of this analysis can be used as primary data for the arrangement of Coast Guard vessels, rigid enforcement of regulations, removal of floating objects, and preparation of countermeasures involving preliminary removal of floating objects to prevent accidents by time and season.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.1
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• pp.22-29
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• 1999

In the development of high speed marine vehicle, lilting devices became important in sharing the pay load or controlling the attitude. The devices are also important to meet the IMO regulation to prevent the marine pollution by keeping the high rudder force for VLCC even in low speed operation. The high lift devices such as the Coanda device have been introduced to the aircraft as a common practice for a long time among the aero-engineers. If the Coanda device can be utilized to the flapped rudder, the severe requirement of rudder force could be provided for the VLCC in low speed operation. The performance of the rudder system has been investigated at the towing tank of Seoul National University.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.1
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• pp.3-24
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• 2000

The provability of major oil spill acidents around Korean coast is very high due to increase of sea traffic and decrease of quality of ships crews and increase of the old-ship. The Strategies of establishment of a advanced response management system against this mass pollution incident are as follows;. 1. Development of Regional Contingency Plan, which is scientifically illuminated, in order to implement the National Contingency Plan efficiently. 2. Early completion of a national response capability twenty thousand tons. 3. To strengthen training and exorcise specialized in the field of marine pollution response. 4. Establishment of a system of response cooperation among neighbor countries by promoting the NOWPAP tasks etc. The response policy in the 21th century should be concentrated to promote a practicle response capability through response operation scientifically specialized and internationalized by establishing the advanced response system early.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.331-336
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• 2004

In order to strengthen the competitiveness of port against calling for the huge vessel and reducing the shipping service time, the productivity of container terminal must be improved. This productivity variously results according to the kinds of productivity evaluation model, input elements like yard, equipment, employee, facility, etc,. But, it is discussed that the productivity is measured by partial productivity evaluation model or general input elements. Therefore, we measured for the productivity of the container terminal using the Developed the data Envelopment Analysis (DEA), which is developed in order to evaluate the relative efficiency of decision making units - it's difficult to clear cause and effect between input and output. We measured the whole productivity of container terminal in Busan according to decision of the correct input elements. And we investigated the change of the productivity measurement result according to input elements, presents more accurate productivity evaluation model in container terminal.