• 제목/요약/키워드: Ships

검색결과 4,433건 처리시간 0.026초

A Study on Intention Exchange-based Ship Collision Avoidance by Changing the Safety Domain

  • Kim, Donggyun
    • 해양환경안전학회지
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    • 제25권3호
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    • pp.259-268
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    • 2019
  • Even if only two ships are encountered, a collision may occur due to the mistaken judgment of the positional relationship. In other words, if an officer does not know a target ship's intention, there is always a risk of collision. In this paper, the experiments are conducted to investigate how the intention affects the action of collision avoidance in cooperative and non-cooperative situations. In non-cooperative situation, each ship chooses a course that minimizes costs based on the current situation. That is, it always performs a selfish selection. In a cooperative situation, the information is exchanged with a target ship and a course is selected based on this information. Each ship uses the Distributed Stochastic Search Algorithm so that a next-intended course can be selected by a certain probability and determines the course. In the experimental method, four virtual ships are set up to analyze the action of collision avoidance. Then, using the actual AIS data of eight ships in the strait of Dover, I compared and analyzed the action of collision avoidance in cooperative and non-cooperative situations. As a result of the experiment, the ships showed smooth trajectories in the cooperative situation, but the ship in the non-cooperative situation made frequent big changes to avoid a collision. In the case of the experiment using four ships, there was no collision in the cooperative situation regardless of the size of the safety domain, but a collision occurred between the ships when the size of the safety domain increased in cases of non-cooperation. In the case of experiments using eight ships, it was found that there are optimal parameters for collision avoidance. Also, it was possible to grasp the variation of the sailing distance and the costs according to the combination of the parameters, and it was confirmed that the setting of the parameters can have a great influence on collision avoidance among ships.

Study on a Fully Electrified Car Ferry Design Powered by Removable Battery Systems Considering Domestic Coastal Environment

  • Hong, Jang Pyo;Kim, Young-Shik;Shim, Hyung-Won;Kang, Hee-Jin;Kim, YunHo;Kim, Gyu Bum;Cho, Seongpil
    • 한국해양공학회지
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    • 제35권1호
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    • pp.1-12
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    • 2021
  • As increasing the international community's awareness of greenhouse gas reduction, the demand for eco-friendly ship fuel has accelerated recently. The fundamental aim of this study is to develop a new type of fully electrified ferry for passengers and cars considering Korean domestic coastal environmental conditions. Several technical difficulties are encountered in applying a fully electric propulsion system based on removable battery systems into a ship due to limitations imposed by the batteries' size and capacity. This paper reviews and analyzes marine environment regulations strengthened recently, technology trends related to fully electric propulsion vessels in each country, and Korean domestic coastal environments. We propose a new fully electrified car ferry design with a displacement of 400 t applied in Korea. It is powered by removable battery systems pre-charged in a safe inland charging station. The mobile battery system is developed to enable roll-on and roll-off using wheels. The characteristics of the ship motion are analyzed based on the weight and location of the battery systems. We expect our battery systems to be applicable to larger ships in the future.

엔진 시동용 소형선 탑재형 파력 발전 시스템 (The Wave Power Generator on Small Ship for Charging Engine Start-Up Battery)

  • 류기수;강성진;유병석
    • 대한조선학회논문집
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    • 제59권6호
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    • pp.439-446
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    • 2022
  • Efforts to reduce carbon dioxide(CO2) emissions are being carried out due to climate environmental problems. Eco-friendly ships are also being developed, and various energy saving measures have been developed and applied. In ships, researches have been conducted in various fields such as electric propulsion system and energy saving devices. In addition, the development of ships using various renewable energy, such as kite using wind power and wind power generation, has been carried out. This paper proposes a plan to use renewable energy for ships by applying wave generators to small ships. In 2016, 130 small domestic ships drifted by sea due to discharge of starting storage batteries, and discharge cases accounted for the largest portion of the causes of domestic ship accidents. This is due to the excessive use of storage batteries for starting the main engine by departing in a weak storage battery state for small ships. Accordingly, two type wave power generators - opened flow wave power generator and enclosed vibrator type wave power generator - are developed for charging a starting storage battery when the ships are stationary at sea or port. Opened flow wave power generator utilizes the flow of fluid in the ship by using wave induced ship motion. Enclosed vibrator type wave power generator utilizes the pendulum kinetic energy located in a ship due to wave induced ship motion.

소형선박을 위한 IMU 센서와 GPS 기반의 경로 추적 시스템 (Path Tracking System for Small Ships based on IMU Sensor and GPS)

  • 조연수;이석훈;정동원
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2021년도 추계학술대회
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    • pp.18-20
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    • 2021
  • 최근 증가하고 있는 선박의 충돌 사고 예방을 위하여 인공지능 기반의 자율운항선박(Maritime Autonomous Surface Ship, MASS)에 관한 연구가 진행되고 있다. 하지만 대부분의 자율운항선박 관련 연구들은 자율운항시스템의 크기와 비용으로 인해 주로 중대형 선박을 그 대상으로 하고 있으며, 여기에 사용되는 센서들은 소형선박에 탑재하기 어렵다는 문제를 지닌다. 따라서 이 논문은 소형선박의 자율운항을 위하여 GPS와 IMU 센서를 탑재한 경로 추적 시스템을 제안한다. GPS와 IMU 센서는 선박의 정확한 위치 파악을 위하여 활용되며, 이를 통하여 제안 시스템은 소형선박 모형을 수동으로 제어하여 경로를 생성하고, 이후 소형선박이 동일한 경로를 이동할 시 Pure Pursuit 알고리즘을 이용하여 경로를 추적하도록 한다. 그 결과, 이 연구는 경량화된 저가의 센서들을 이용하여 소형 선박의 자율운항 시스템을 저비용으로 개발할 수 있을 것으로 기대된다.

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함정의 공기중 소음수준 (Airborne Noise Level of Navy Ships)

  • 김종철;박일권;김경용;안호일
    • 한국군사과학기술학회지
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    • 제5권4호
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    • pp.27-37
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    • 2002
  • Airborne noise is one of the considerable environmental factors for navy ship personnel because of accomplishing their tasks on restricted ship spaces. In this study, the effects of airborne noise on personnel and existing criteria for acceptable airborne noise on ships are reviewed briefly. Statistic results of airborne noise levels of the Korean navy ships are analyzed according to the class of ships and are compared airborne noise levels of the US navy ships. These results can be used for proposing airborne noise criteria of the navy ship for the future.

A Study on the Correlation Analysis of the Present Status of Positive Displacement Pumps Installed in Ships

  • Lee, Sang-Il;Kim, You-Taek
    • Journal of Advanced Marine Engineering and Technology
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    • 제32권3호
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    • pp.421-429
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    • 2008
  • Various kinds of ship are operated to transport cargo or passengers at sea in the world. Most of the important auxiliary machineries installed in those ships are fluid machineries such as pumps, compressors, and fans. A large percentage of fluid machinery is pumps which are classified turbo and positive displacement pumps. This paper analyzes only positive displacement pumps. This thesis has two aims: (a) to analyze the present status of pumps installed in merchant and training ships and (b) to find the correlation among sea going pump kW, port pump kW, total pump kW, GE kW, ME MCR, number of pumps, ME kgf, pump kgf. Based on ship's type, this paper seeks to find special characteristics as a result of analyzing head, flow rate, and kW. Moreover this paper analyzes and compares number of pumps, pump kW/ME MCR, pump kW/GE kW under the conditions of seagoing and berthing according to ship's type.

중소형선(中小型船)의 기관부중량추정(機關部重量推定) (Estimation of Machinery Weights of the Medium and Small-sized Ships)

  • 김극천
    • 대한조선학회지
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    • 제3권1호
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    • pp.25-32
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    • 1966
  • For preliminary estimation of ships' machinery weights, many papers giving well-judged data and discussions for rational method of estimation, such as [1], [2], [3], [4], [5], [6], are available, however, they are mostly concerned with large ships propelled by power more than about 2, 000 horsepower. Regarding the medium and small-sized ships, as far as the author is aware, fragmental data and vague discussions found in various technical literature are the all available. In this paper, available data concerned with machinery weights of commercial ships propelled by direct-drive diesel plants of power below 3, 000 horsepower with single screw propeller are collected and analysed to obtain systematic data Fig. 1 and Fig. 2 as weight to power ratio versus power per shaft diagrams together with suplementary data Fig. 1 and Fig. 3. Influences of various factor such as revolutions per minute, mean effective pressure, type and construction of the main units on machinery weights are also investigated in detail to give a better guidance for logical and rational utlization of the proposed diagrams in preliminary estimation of machinery weights.

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우리 나라 연안여객선 보조항로의 운항수지분석과 보조금 적정성에 관한 연구 (Analysis on the Profitability of Coastal Passenger Ships on the Subsidized Routes and Optimization of the Subsidy)

  • 이태우;임종길
    • 한국항해학회지
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    • 제23권3호
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    • pp.45-59
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    • 1999
  • This paper aims, first to analyse the profitability of coastal passenger ships deployed on both subsidized and non-subsidized routes, ie competitive routes, in Korea, second to evaluate them by route, by ship type, and by ship size, and finally to identify whether the ships deployed on subsidized routes are justifiable to receive subsidy from the government. They are followed by the analyses on the profitability of all ships on the coastal routes and their dependence rate of subsidy. The research covers the period of 1995-1997. The research results say that 35% of the total subsidized routes has more than 90% of subsidy dependence rate and that some monopolized routes among subsidized ones with moderate rate of profitability need to be crossed out from the list of subsidy beneficiary. In addition, some ships deployed are not appropriate type in terms of characteristics of route and traffic. One of implications drawn from this study is that the government has to set up a watchdog to monitor subsidized routes, which enables to make them competitive and save the budget.

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