• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.4
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• pp.432-438
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• 2017

The primary objective of the current work was to develop a standardized retrofit hull form capable of saving energy based on existing vessels. The bow shape of existing vessels was investigated, giving consideration to design draft and speed. Resistance performances were assessed for existing vessels according to operating conditions. Commercial CFD codes and model test materials were used for assessment of effective power. Three retrofit hull forms with minimum resistance were selected given real operating conditions. These vessels were named after customized ready-made hull forms to enable ship owners to make easier choices. The effective power of each vessel was estimated under real operating conditions. Subjects were operated with the lowest draft, and performance for retrofit No. 3 showed an 11-16% improvement in effective power at low speed ranges of 16-18 knots compared to existing vessels. When operated with a middle draft, performance for retrofit No. 3 showed a 6-11% improvement in effective power at low speed ranges compared to existing vessels. When operated with the highest draft, performance for all vessels showed little difference in effective power.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.205-212
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• 2005

Since special sea area for traffic safety has been established in 1988, there has been only deep water line for deep draft vessels and no other ships' routeing measure for special sea area on Yeosu Bay. In this work, we suggest several solutions to secure ship's safety and to eliminate dangerous factors which exists in present ship traffic system. Consequently, this work is to propose improved marine traffic system in future.

• Journal of Navigation and Port Research
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• v.29 no.8 s.104
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• pp.653-660
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• 2005

There has been only a deep water route for deep draft vessels without any other routeing system in Yosu Bay despite of the rapid change in ship's size and increase in the traffic volume since the specified area for traffic safety was established in 1988. In this work, we suggest several solutions to secure ship's safety and to eliminate dangerous factors which exists in present ship traffic system Consequently, this work is to propose improved marine traffic system in future.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.2
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• pp.97-111
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• 2006

Using the eigenfunction expansion method, a mathematical model has been developed to calculate the reflection and transmission of regular waves from a multiple-row curtainwall-pile breakwater. In addition, hydraulic model experiments have been conducted with different values of porosities between the piles, drafts of the curtain walls, and distances between the rows of the breakwater. It is found that the reflection and transmission coefficients decrease and increase, respectively, with decreasing relative water depth, but they bounce to increase and decrease, respectively, as the relative water depth decreases further. When either the porosity between the piles or the draft of the curtain wall is changed with other parameters fixed, the relative magnitudes of the reflection and transmission coefficients have been changed, but the general trend remained the same. When the wavelength is the same as the distance between the rows of the breakwater, a rapid change was observed for the reflection and transmission coefficients. A good agreement between the measurement and prediction was also founded for three-row breakwaters.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.3
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• pp.469-475
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• 2010

The operation scenarios, types of ice, draft and propulsion system are important design point on the beginning stage of the ice breaking vessel. The concept of hull form in ice breaking vessel has to compromise the performance according to the operation route especially if ship is operating in ice and ice free water. The several hull forms were proposed to optimize the capability of the vessel in this paper. The effect of hull form according to type of ice is also discussing and explaining the ice resistance in each ice type as like pack ice, brash ice, level ice, rubble ice and ice ridge. The draft effect was examined and propulsion system for example FPP(Fixed pitch propeller), CPP(Controllable pitch propeller) and POD system was compared focusing on the propulsion efficiency.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.338-340
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• 2014

"정박지"라 함은 기본적인 수역시설의 하나로 선박이 정박할 수 있는 장소로 선박들은 이곳에 투묘함으로써 법적, 물리적 보호를 받게 된다. 정박지는 해당 항만에 입 출항 대기 또는 작업대기 등의 목적을 위해 해당항만에서 지정 고시하여 운영하고 있다. 하지만, 마산항의 정박지의 경우 비상정박지를 제외하고는 흘수 6m이상의 선박이 투묘 대기할 수 있는 정박지가 부재하다. 이런 사정으로 현재 마산항 입항대기 선박 및 작업대기 선박들의 경우 지정된 정박지가 아닌 잠정 정박지와 관습적 정박지에 투묘대기하고 있는 실정이다. 이로 인해 선박 및 관제사 모두 법적, 물리적 보호를 받지 못하고 있다. 따라서 본 조사는 마산항의 현황파악을 통해 항만 운영, 관제운영 및 이용자 측면에서 마산항의 정박지 추가 필요성에 대한 내용을 검토하여 "마산항의 정박지 지정에 관한 연구"의 기초자료로 이용하고자 한다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.2
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• pp.41-48
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• 2000

An experimental study is made to improve the efficiency of floating breakwaters. Wave transmission coefficients highly depend on the drafts of the floating breakwaters but not on the mooting chain weights. Array of two breakwaters can improve the efficiency of the floating breakwaters. Proper draft combination of the fore and the aft bodies may improve the performance of the floating breakwaters lot various wave periods.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.10a
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• pp.48-50
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• 2013

해상에서의 선박충돌사고 예방에 대한 연구가 IMO를 중심으로 꾸준히 지속되어 왔다. 이러한 항해장비 중에서 AIS는 중요한 역할을 수행하여 왔다. AIS 장비를 통하여 전송되는 정보에는 정적 정보와 동적 정보 및 항해 관련 정보로 구분할 수 있다. 정적 정보에는 MMSI, 선명, 호출부호, IMO번호, 선박길이 및 선폭, 선종 등 선박이 이동해도 변하지 않는 정보로 구성되고, 동적 정보에는 선박의 위치, 시간, 대지침로, 대지속력, 선수방위, 항행상태, ROT(Rate of Turn) 등 선박이 이동함에 따라 변화하는 정보로 구성된다. 그리고 항해 관련 정보에는 흘수, 위험화물, 목적지, ETA 등이 해당된다. 하지만, 이러한 정보들에 대한 활용도의 우선순위 및 정보의 적정성 등에 대해서는 아직까지 조사된 것이 없는 실정이다. 본 연구에서는 AIS 장비의 실 사용자를 대상으로 한 설문조사 및 분석을 통하여 AIS 송수신 정보들에 대한 활용도의 우선순위 및 정보의 적정성 등에 대해 검토해보고 필요시 개선 필요성을 제시하며 아울러 AIS 장비의 개선점도 검토해 보고자 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.6A
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• pp.549-554
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• 2002

In this paper, for n=2m and odd prime p, new generalized bent functions from the finite field $F_{p^n}$ to the prime field $F_p$ are constructed from the partial spreads for $F_{p^n}$. Closed form expressions for the proposed generalized bent functions and their trace transform are derived in the form of the trace functions.

• 한국전산유체공학회:학술대회논문집
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• 2004.10a
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• pp.33-36
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• 2004

The ballast tank of a ship is a system that realizes the required shipping condition and controls the draft of a ship. The loading/unloading of the ballast tank is frequently operated during navigation and the accurate prediction of the loading/unloading time is very important. A numerical algorithm that predicts the loading/unloading time of the ballast tank has been developed and applied to the prediction of the loading/unloading time of the ballast tank with various piping systems. This algorithm can be useful in optimizing the ballast tank system in early design stage.