• 대한조선학회논문집
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• 제52권6호
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• pp.452-459
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• 2015

It is important to use bench test results in the design process of anti-rolling tanks. Traditional bench tester is usually designed to perform only roll motions about a fixed axis and relatively small so that the viscous effects may not be neglected. Novel bench tester which could adjust the motion center to realize the coupled motion of sway and roll has been devised and manufactured therefore, large scaled bench tester could be utilized for designing the passive anti-rolling tanks. The time history of the reference signal from the rotation sensor of the bench tester have been recorded and processed to determine the phase angle to derive the Response Amplitude Operator(RAO) of the stabilized ship. The breadth of ART tank model should be large up to 2 m to diminish viscous scale effect and the vertical position of the tank can be varied with the ship's center of motion. The periods and the amplitude of roll motion can be varied from 1.5 sec to 5 sec and up to ±20°, respectively. The components of the tester was expressed in three dimensional digital mockup (DMU) and assembled together in the CAD space. The final configuration of the bench tester has been determined by confirming the smooth operation of the moving parts without interference through the animation in CAD space. New analytic logic are introduced for the determination of hydrodynamic moment and phase difference due to fluid motion in ART and verified through the test. The developed bench tester is believed to be effective and accurate for the verification of stabilization effect of ART taking into the consideration of the sway effect in the design stage.

• 시큐리티연구
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• 제14호
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• pp.109-123
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• 2007

대중교통수단에 대한 테러는 운송수단을 대상으로 한 테러유형 중의 하나이지만, 항공기나 선박과는 달리 인질협상을 하는 사례는 거의 발견할 수 없고 무차별 공격을 가하기 때문에 인명피해가 매우 크다. 그러므로 더욱 철저한 대비가 필요함에도 불구하고 항공기에 비해 방어기제는 거의 마련되어 있지 않은 실정이며, 시민의 입장에서도 열차나 버스 등을 이용할 때 테러에 대한 대응태세는 전무한 상태여서 문제가 매우 심각하다. 그렇기 때문에 이러한 대중육상교통수단에 대한 테러를 예방하기 위해서는 KTX 등 열차탑승자의 신원확인과 수화물 검색을 실시해야 한다. 또한 열차보안요원의 대테러 능력 강화, 시민의 대테러 훈련 정례화, 시설물의 철저한 점검, 사회적 안전망 확충등이 시급히 이루어져야 한다. 모든 테러는 우리가 자주 이용하는 시설이나 수단을 대상으로 삼기에 평상시에 철저히 점검하고 대비하는 자세가 테러를 방지하는 가장 확실하고 안전한 대응방안이 될 것이다.

• 대한조선학회논문집
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• 제50권5호
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• pp.307-313
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• 2013

This paper presents a simulation for passenger ship evacuation considering determination of evacuating direction based on walking direction potential function. In order to determine walking direction of a passenger, his/her position in two dimensional plane was adopted as a design variable, and fixed boundaries such as walls and obstacles were adopted as constraints. To solve this optimum problem, a walking direction potential function was adopted as an objective function. This potential function was configured as a kind of penalty function and it contained two components. One is a potential function concerned with the distance to the destination, and other is a potential function based on the effect of walls and obstacles. To determine evacuating direction, this problem was solved by minimizing the walking direction potential function every unit time during the simulation. The crowd behavior of the passenger consisted of the flock behavior, a form of collective behavior of a large number of interacting passengers with a common group. With the proposed algorithm, the test problems in International Maritime Organization, Maritime Safety Committee/Circulation 1238(IMO MSC/Circ.1238) were implemented and the direction of passengers and total evacuation time was analyzed.

• 무역상무연구
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• 제70권
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• pp.39-65
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• 2016

On 2013 the English court delivered a decision that the payment obligation under time charter party is a condition. According to this judgement, The Astra, a breach of the obligation to pay hire on time entitles the owner both to withdraw the ship and sue the charterers for damages for the difference between the contract and market rate for the remainder of the contracted period. On 2015, however, the English court stood at the other side. In Spar Shipping, the court confirmed that the obligation to pay hire is not a condition of the contract but an "innominate term" - from the charterers' breach ship owners can exercise their contractual right to withdraw, but owners' right to sue for damages depends on whether the charterers have deprived the owners of the substantial benefit of the contract, or shown an intention to do so. This article aims to compare both decisions over the points that (1) the importance of on-time payment under a time charter party, (2) as a critical and main question in this article, whether the mattered payment clause is a condition or innominate term, (3) whether the on-time payment clause is merely a penalty or a reasonable liquidated damage. Based on various reasons, I am on a position that the payment of hire is not a condition but an innominate term. Default in punctual payment by a charterer, in the absent of clear contractual agreement, needs to be decided further whether that breach removes the substantial benefit of the contract from the owners.

• 디지털융복합연구
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• 제11권1호
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• pp.211-223
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• 2013

국내 컨테이너터미널에서는 야드 트랙터의 위치를 실시간으로 인식하기 위해 RFID시스템을 사용하고 있다. 그러나 RFID를 이용한 위치인식은 트랜스퍼 크레인을 이용하는 야드 작업에는 문제가 없으나, 컨테이너 크레인을 이용하는 본선 작업에는 문제가 있다. 즉, 컨테이너 크레인에서 크레인 밑의 4개 차선에서 움직이는 야드 트랙터들을 구분하여 정확히 인식하기가 불가능하기 때문이다. 따라서 본 논문에서는 트랜스퍼 크레인의 야드 작업은 물론이고 컨테이너 크레인의 본선 작업에서도 동일한 방식으로 정확히 야드 트랙터를 인식할 수 있는 적외선 통신시스템을 개발하였다. 본 연구의 결과 인식 횟수가 일정하게 측정되었으며, 25m의 거리에서도 인식범위가 5.7m로 측정 가능하였다. 즉, 컨테이너 크레인 밑을 이동하는 여러 대의 야드 트랙터들을 구분하여 인식할 수 있는 인식 범위를 가지게 되었다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권3호
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• pp.562-577
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• 2014

A reliable steady/transient hydro-elastic analysis is developed for flexible (composite) marine propeller blade design which deforms according to its environmental load (ship speed, revolution speed, wake distribution, etc.) Hydro-elastic analysis based on CFD and FEM has been widely used in the engineering field because of its accurate results however it takes large computation time to apply early propeller design stage. Therefore the analysis based on a boundary element method-Finite Element Method (BEM-FEM) Fluid-Structure Interaction (FSI) is introduced for computational efficiency and accuracy. The steady FSI analysis, and its application to reverse engineering, is designed for use regarding optimum geometry and ply stack design. A time domain two-way coupled transient FSI analysis is developed by considering the hydrodynamic damping ffects of added mass due to fluid around the propeller blade. The analysis makes possible to evaluate blade strength and also enable to do risk assessment by estimating the change in performance and the deformation depending on blade position in the ship's wake. To validate this hydro-elastic analysis methodology, published model test results of P5479 and P5475 are applied to verify the steady and the transient FSI analysis, respectively. As the results, the proposed steady and unsteady analysis methodology gives sufficient accuracy to apply flexible marine propeller design.

• 한국해양공학회지
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• 제18권6호
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• pp.79-83
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• 2004

The curved blocks which compose the bow and stem of a ship contain many skewed joints that are inclined horizontally and vertically. Most of these joints have a large fitness error and are continuously changing their form and are not easily accessible. The welding position and parameter values should be appropriately set in correspondence to the shape and the inclination of the joints. The welding parameters such as current, voltage, travel speed, and melting rate, are related to each other and their values must be in a specific limited range for the sound welding. These correlations and the ranges are dependent up on the kind and size of wire, shielding gas, joint shape and fitness. To determine these relationships, extensive welding experiments were performed. The experimental data were processed using several information processing technologies. The regression method was used to determine the relationship between current voltage, and deposition rate. When a joint is inclined, the weld bead should be confined to a the limited size, inorder to avoid undercut as well as overlap due to flowing down of molten metal by gravity. The dependency of the limited weld size which is defined as the critical deposited area on various factors such as the horizontally and vertically inclined angle of the joint, skewed angle of the joint, up or down welding direction and weaving was investigated through a number of welding experiments. On the basis of this result, an ANN system was developed to estimate the critical deposited area. The ANN system consists of a 4 layer structure and uses an error back propagation learning algorithm. The estimated values of the ANN were validated using experimental values.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.59-66
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• 2006

This research is based on the information compiled on the occurrence of maritime casualties onboard ships registered under Central American Region (CAR) flag States. Due to nonexistence of writing reports in anyone of the countries that are integrating this Region, the information was compiled by the author through personal communication with the people involved in the casualties. The information was compiled by typing up the text and digitizing on the computer for the respective data base. For each casualty occurred, the following information was compiled, date and type of the casualty, position of the ship at the time of the casualty, dimension of the ship, number of people affected by the casualty, and cause and consequences of the casualty. Based on the number of people affected (death and disappear) by the casualties occurred was calculated the mortality rate by 100,000 persons and then compared with the Japanese mortality rate. Furthermore were analyzed the CAR maritime authorities competences and then were compared to that the Japanese counter part. In addition, the implementation rate of the International Maritime Organization (IMO) and International Labor Organization (ILO) conventions ratified by the CAR countries were analyzed. The objective of this research was to compiled and analyze the occurrences of maritime casualties happened on board the ships registered under the CAR Flag States, in order to determine the causes of these accidents. The results of the analysis enable us to better understand of the maritime safety situation of the ships that are registered under the CAR flag States. In order to reduce the occurrence of maritime casualties are proposed a series of measures based on the differences found then the comparison between CAR and Japan. Based on the results of this research, is possible to conclude that the inaccessibility of atmospheric information and the lack of safety measures onboard has been the main cause of the maritime casualties happened in the Pacific side of the CAR.

• 한국항해항만학회지
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• 제37권4호
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• pp.337-343
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• 2013

정박중인 선박의 안전을 위하여 항해사, 선장 및 해상교통관제사는 항상 선박이 주묘되고 있는가를 확인하여야 한다. 정박선의 주묘판별을 위하여 VTS 관제사가 선회권과 그 중심을 인지하는 것이 중요하다. VTS에서 정박선 주묘여부 감시는 레이더 및 AIS를 이용할 수 있다. 또한 이용가능하다면, CCTV 영상이나 육안에 의한 관측도 이루어 질 수 있다. 그러나 VTS 시스템은 AIS 및 ARPA Radar로부터 수집된 데이터만으로 정박선을 모니터링하고 있으므로 정박지내에서 정박선의 선회중심을 알기가 어렵다. 본 연구에서는 VTS에서 AIS에 의해 수집된 정박 선박의 선수방위각과 위치데이터를 활용하여 선회중심을 추정하는 알고리즘을 제시하고자 한다. 알고리즘의 유효성을 확인하기 위해, 실 환경에서 정박한 선박에 대한 실험연구를 수행하였다.

• 대한조선학회논문집
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• 제41권3호
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• pp.60-71
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• 2004

Nowadays, We have had a growing interest in high-speed vessels' because it is very important to save time and cost in marine transportation. The development of hull form for high-speed vessels is high priority to secure the competitive power for the transportation of cargos. Therefore, the demand of the high-speed vessels is gradually increased, but the conventional hull forms are limited by rapidly increasing resistance upon the increase of ship speed in high-speed region. Therefore, new concepts for the hull form of high-speed vessels have been requested. One of the derived hull forms for that demand is the hull form of trimaran type. Trimaran has a very slender main hull as compared with conventional single hull so that is reduced in wave resistance. The slender main hull has the undesirable characteristics of stability, but two side hulls make up for the week points in the stability. That is, trimaran is able to have desirable performances for the resistance and stability. In this paper, for the design of 200TEU class container vessel with trimaran type, which will be cruised in Yellow-Sea region, firstly a preliminary hull is designed, and the model test is carried out with the variation of side hull position. From the experience of the preliminary hull form design, an improved hull form for the 200TEU container are designed, and the model tests are carried out. Also, a numerical computation technique is adopted for the simulation of flow phenomena around the designed hull forms. The final hull form is compared with existing ships for the resistance performance from the computation with computer and ship model tests.