• 한국항해학회지
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• 제7권2호
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• pp.65-113
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• 1983

A lot of studies of ship's economy are on the traditional fields such asreducing propulsion resistance, raising cargo handling rates and lessening building consts, but there are few researches on the merchant ship's economy concerning their deadweights and speeds according to shipping companies managerial cercumstances. Contrary to the contemporary trend that "the bigger, the better, if the cargo handling rate could increased sufficiently to hold down port time to that rate of smmaler vessels", this paper demonstrates the existence of certain limits in ship's size and speed according to the coditions of the freight rates, voyage distances, cargo handing rates, prices of fuel oil, interst rates etc. Fom the curves of criteria contour for various ship's deadweights and speeds which are depicted from the gird search method, one can get the costs and the yearly profit rates under the conditiions of large volume with long term contracts for the transportation of bulk cargoes. In estimating ship's transportation economy, the auther takes the position that the profit rate method is properer than the cost method, and introduces the calculation table of the voyage profit rate index. The use of the criteria contours will be of help to ship owners in determining the size and speed of the ship which will be built or purchased and serve in a certain trade route.

• 한국지능시스템학회논문지
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• 제16권5호
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• pp.635-641
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• 2006

Ship's collision avoidance is a skill that masters of merchant marine vessels have acquired through years of experience and that makes them feel at ease to guide their ship out from danger quickly compared to inexperienced officers. Case based reasoning (CBR) uses the same technique in solving tasks that needs reference from variety of situations. CBR can render decision-making easier by retrieving past solutions from situations that are similar to the one at hand and make necessary adjustments in order to adapt them. In this paper, we propose to utilize the advantages of CBR in a support system for ship's collision avoidance while using fuzzy algorithm for its retrieval of similar navigational situations, stored in the casebase, thus avoiding the cumbersome tasks of creating a new solution each time a new situation is encountered. There will be two levels within the Fuzzy-CBR. The first level will identify the dangerous ships and infer the new case. The second level will retrieve cases from casebase and adapt the solution to solve for the output. While CBR's accuracy depends on the efficient retrieval of possible solutions to be adapted from stored cases, fuzzy algorithm will improve the effectiveness of solving the similarity to a new case at hand.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2006년도 추계학술대회 학술발표 논문집 제16권 제2호
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• pp.39-44
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• 2006

Ship's collision avoidance is a skill that masters of merchant marine vessels have acquired through years of experience and that makes them feel at ease to guide their ship out from danger quickly compared to inexperienced officers. Case based reasoning(CBR) uses the same technique in solving tasks that needs reference from variety of situations. CBR can render decision-making easier by retrieving past solutions from situations that are similar to the one at hand and make necessary adjustments in order to adapt them. In this paper, we propose to utilize the advantages of CBR in a support system for ship's collision avoidance while using fuzzy algorithm for its retrieval of similar navigational situations, stored in the casebase, thus avoiding the cumbersome tasks of creating a new solution each time a new situation is encountered. There will be two levels within the Fuzzy-CBR. The first level will identify the dangerous ships and index the new case. The second level will retrieve cases from casebase and adapt the solution to solve for the output. While CBR's accuracy depends on the efficient retrieval of possible solutions to be adapted from stored cases, fuzzy algorithm will improve the effectiveness of solving the similarity to a new case at hand.

• 해양환경안전학회지
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• 제25권3호
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• pp.320-327
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• 2019

The purpose of this paper is to compare seafarers' behavior according to traffic conditions of a road and an onshore locations. Behaviors are classified into three categories: Skill-, Rule- and knowledge-based mode. Experimental data were collected using the questionnaires for navigators, working in a merchant ship. To compare the behaviors, we used the four analysis method; the degree of frequency, reliability test, correlation and linear regression. As a result of the study, it was found that Skill-based behavior shows more higher in the road traffic than the maritime traffic, and rule-based behavior shows more higher in the maritime traffic than the road traffic. Also, the behavior in the navigation situation showed statistical significance. Especially, in the case of Rule-based behavior, a high correlation between road and maritime was found. This study can be expected to apply to complementary system utilization between error management system of onshore and maritime traffic.

• 한국항해항만학회지
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• 제46권2호
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• pp.99-109
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• 2022

A report released by the Chinese Maritime Court found that the natural environment and other objective factors have greatly reduced the risk of ship collision accidents with the advancement of technologies. However, collisions between merchant ships and fishing boats occur frequently along the coast during fishing seasons, which should be highly valued. International conventions and domestic legislation in China comprise detailed laws with respect to ship collisions, but the theory of ship collision infringement needs to be improved, enriched, and developed. Meanwhile, the development of the tort liability law provides theoretical support for ship collision infringement. As far as China's ship tort legal system is concerned, the research on ship collision tort damage compensation is relatively extensive, and the constitutive elements and causality of ship collision tort liability have also been studied in depth. The purpose of this paper is to explore the domestic legislation applicable to disputes related to ship collisions in China. As these laws are unclear on the resolution of disputes resulting from ship collisions, significant attention has been focused on the final judgments by the Supreme Court of China (SPC), as well as the judicial judgments set by the Maritime Court of China.

• 한국해양공학회지
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• 제37권4호
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• pp.129-136
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• 2023

To evaluate manoeuvring performance of merchant ships, the mathematical modeling group (MMG) or computational fluid dynamics (CFD) simulations are used. However, it is difficult to use the MMG to evaluate the manoeuvring performance of fishing vessels, thus research using CFD simulations is necessary. Also, since the course-changing and turning ability is crucial in fishing operations, a rudder design suitable for fishing vessels is necessary. This study designs a rudder using National Advisory Committee for Aeronautics (NACA) airfoil sections and evaluates its manoeuvring performance. A CFD model is used to evaluate the manoeuvring performance of the fishing vessel, and turning and zig-zag tests are conducted. The effectiveness of using CFD simulations based on Reynolds averaged Navier-Stokes equations to assess the manoeuvring performance of fishing vessels was validated. No significant difference was found in the manoeuvring performance for hull forms and rudder designs for course-changing ability. However, the original hull form showed superior turning performance. Among five rudders with varying aspect ratios and shapes, the rudder with 5.5% aspect ratio had the best turning performance. Regarding the rudder design for fishing vessels, NACA airfoil was employed, and a rudder aspect ratio of 5.5% based on the immersed hull side area is recommended.

• 수산해양기술연구
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• 제56권3호
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• pp.246-257
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• 2020

According to the statistics of KMST (2010~2019), 68.5% of marine casualties have been occurred in fishing boats in the last 10 years. Although the incidence rate of annual average per ship is 10.4% for merchant ships and 2.3% for fishing boats, it is necessary to first reduce the marine casualties of fishing boats in order to reduce the occurrence of the whole marine casualty, considering that the number of registered fishing boats are 86.5% of the total. In this study, the top 10 fishing types with high occurring marine casualties in the past 10 years were selected using the statistics of KMST. Then, the causes of the marine casualties, focusing on the collision, were analyzed and counterplan were suggested. The biggest marine casualty that the top 10 fishing types have caused in the past 10 years was a collision, accounting for 71.7% of the total, and the rest were less than 10.0% each. Also, it was found that the biggest environment and cause of the collision were due to human factors such as poor look out or negligence of duty. Eventually, it was concluded that a reduction in the human factors for the causes basically, could lower the incidence of the marine casualties. Therefore, if the continuous and systematic correcting education of the attitude toward the ship operating of seafarers could conducted with the focus on the main human factors, the whole marine casualties will be expected to decrease gradually.

• 수산해양교육연구
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• 제29권3호
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• pp.857-868
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• 2017

The basic safety training for fisheries is being conducted to cope with an emergency situation and prevent the maritime accidents. A new joined person must be educated the safety training and a refresher must be completed the refresher training course every 5 year in according to the STCW-F and seafarers' Act. In order to achieve the objectives of marine safety training, it is necessary to distinguish the trainees by ship's type and the courses should be implemented in consideration of safety equipment of fishing vessels. However, since the classification criteria of seafarers' Act are unclear, the officer of fishing vessels which is over G/T 25 tons has been trained through the same course and curriculum for merchant ship's seafarers. About 80 % of domestically registered fishing vessels are small size ships(less than 100 tons) and there is not many safety equipment required by law. In case of marine accidents such as collision, the small vessel losses its buoyancy and stability caused by damage of hull. despite fisheries fall into the sea during fishing work in bad weather on the deck, there was no safety equipment by law. So fisheries must be trained by a safety training course suitable for fishing vessel. The purpose of this study is to develope the suitable course for fisheries by analysis current curriculum and rules. so suggested the basic safety training course for fisheries and institutional improvement.

• International Journal of Ocean System Engineering
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• 제2권4호
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• pp.239-243
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• 2012

The cylinder liner of a low speed engine is one of the most important parts of the marine diesel engines used in merchant ships. However, a sufficient degree of precision in the manufacturing method for these cylinder liners has never existed. Conventional honing stones have always been used for machining large marine cylinder liners. Therefore, it is necessary to develop a honing process that optimizes the honing characteristics. In this study, a CBN honing stone was manufactured to improve the honing performance for a cylinder liner and shorten the processing time, and machining experiments on a practical cylinder liner were carried out. Then, a comparison was made between the CBN honing and honing with a conventional GC stone using parameters such as the honing time, machining quantity, and honing cost. As a result, for a #60 CBN stone, the machining amount was significantly improved compared to the conventional one by about $1.1{\mu}m$/min, and in respect to the machining cost, a reduction of about 57% was achieved. However, an improvement in the process with a #800 CBN stone could not be expected because it did not show a significant difference compared to the case of the existing stone. From the above results, if the liner were honed using a CBN honing stone, the rough machining and intermediate processing during an early stage of the honing process were excellent compared to the conventional one. However, we could not find a significant difference in the case of finish honing.

• 한국항해항만학회지
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• 제28권6호
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• pp.475-480
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• 2004

본 연구에서는, 충돌회피지원을 위한 자동제어에 관하여 새롭게 얻은 몇 가지 성과에 대하여 소개하려고 한다. 그 내용의 첫 번째는 그 동안의 기존 연구에서 해결되지 못하였던 집단 선박의 충돌 회피 이론이다. 이 이론은 선박이 무리를 지어 있는 어선 군을 만났거나, 혹은 무리를 지어 접근하는 선박군에 대한 충돌회피 동작에 유용한 알고리즘이다. 피항동작을 계산하는 단계에서 새로운 알고리즘을 적용한 모델을 적용하여 그 유용성을 설명하였다. 두 번째로는 충돌위험도 계산의 통합화 모델 제시이다. 선박의 경우 유지선, 피항선, 추월선, 피추월선 등 상대 선박과의 다양한 조우 상황에 따라, 항해사의 느끼는 위험도 그리고 피항 의무 등에 조금씩 차이가 있다. 이러한 현상을 반영하기 위하여, 충돌회피 동작에 사용하는 위험도 계산을 수행할 때, 조우상황에 따라 적절히 차별을 주는 모델을 제시하였다. 마지막으로는 이렇게 제시된 모델을 이용하여 다양한 상황에 따라 시뮬레이션을 통하여 검증해 보고, 그 유효성을 살펴보았다.