• 제목/요약/키워드: Ships

검색결과 4,395건 처리시간 0.031초

유사도 기반 해양 자켓 구조물 손상추정 (Similarity-based Damage Detection in Offshore Jacket Structures)

  • 민천홍;김형우;박상현;오재원;남보우
    • 한국해양공학회지
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    • 제30권4호
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    • pp.287-293
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    • 2016
  • This paper presents an effective damage detection method for offshore jackets using natural frequency change ratios. Two parameters, cosine similarity and magnitude index, are considered to estimate the location and severity of the damage in the structure. A numerical jacket structure model is considered to verify the performance of the proposed method. As observed through analysis, the damages in the structure are detected accurately.

혁신성장동력으로 자율운항선박 및 기술개발(R&D) 추진 계획 (A Plan as the Innovative Growth Engine and Technology Development(R&D) for Autonomous Ships)

  • 장화섭;김진
    • 한국항해항만학회:학술대회논문집
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    • 한국항해항만학회 2019년도 춘계학술대회
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    • pp.228-229
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    • 2019
  • 자율운항선박은 전통적인 제조중심, 단순 화물 운송의 조선해운산업에서 패러다임을 전환시키는 게임 체인저로 부상하고 있다. 이에 정부에서도 자율운항선박 산업을 혁신성장동력으로 육성하고, 시장 경쟁력 확보에 필요한 핵심기술을 개발하기 위한 구체적인 추진계획을 소개한다.

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Experimental Evaluation for Hydrodynamic Performance of a Hybrid Supported Type Fast Craft

  • Yang, S.I.;Koh, C.D.;Ahn, J.W.;Kim, Y.G.;Lee, J.-T.
    • Journal of Ship and Ocean Technology
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    • 제4권4호
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    • pp.34-44
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    • 2000
  • This paper deals with the sea trial results of a fast craft with the hybrid supported type hul form. waterjet propulsion system and motion control system. The hybrid-type container ship operable in the sea with a wave height of y6 m, a speed of 50 knots and a payload of 1,500 tons were designed. A 1/8 scale 10 m- long test craft was constructed and tested in open seas. The hydrodynamic performance such as speed, turning, motion control in waves and waterjet thrush was analyzed.

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항만하역노동력의 최적배분에 관한 연구 (II) 선박군의 경우 (OPTIMUM ALLOCATION OF PORT LABOR GANGS IN CASE OF MULTIPLE SHIPS)

  • 이철영;우병구
    • 한국항해학회지
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    • 제13권3호
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    • pp.37-44
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    • 1989
  • Recently recognize the labor productivity of port physical distribution system in the port and shipping areas, Much Efforts for evaluating this productivity has been made continuously. BUt still there is little study, so far, on a systematic research for the management of port labor gangs, and even those were mainly depended on a rule of thumb. Especially the object of this study is to introduce the method of optimal allocation and assignment for the labor gangs per pier unit in the multiple ships berthed at an arbitary pier or port. In case the multiple ships have a homogeneous cargoes or do not have sufficient labor gangs to be assigned. The problem of optimal allocation and assignment of the labor gangs to be i) formalized with multi-state decision process in form of difference equation as the pattern which converted the independent multiple ships into a single ship with the intra-multiple ships, and ii) the optimal size of labor gangs could be obtained through the simple mathematical method instead of complicated dynamic programming, and iii) In case of shortage of labor gangs available the evaluation function considering the labor gangs available and total shift times was introduced, and iv) the optimal allocation and assignment of labor gangs was dealt at the point of minimizing the summation of the total shift times and at the point of minimizing the total cost charged for the extra waiting time except PHI time during port times for the multiple ships combinations.

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Assessment of Safe Navigation Including the Effect of Ship-Ship Interaction in Restricted Waterways

  • Lee, Chun-Ki
    • 한국항해항만학회지
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    • 제27권3호
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    • pp.247-252
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    • 2003
  • This paper is mainly concerned with the assessment of safe navigation between ships moving each other in restricted waterways. The numerical simulation of manoeuvring motion was conducted parametrically to propose an appropriate safe speed and distance, which is required to avoid sea accident under the different conditions, such as ship-velocity ratios, ship-length ratios, separation and stagger between ships. As for the calculation parameters, the ratios of velocity difference between two ships were considered as 0.6, 1.2, 1.5 and the ones of ship-length difference were regarded were regarded as 0.5, 1.0, 1.18. From the inspection of this investigation, it indicates the following result. Firstly, the separation between ships is more needed for the small vessel, compared to the large vessel. Secondly, the lateral distance between ships is necessarily required for the velocity ration of 1.2, compared to the cases of 0.6 and 1.5. The manoeuvring characteristics based on this investigation will be very useful for keeping the safety of navigation from the practical point of ships design and traffic control in confined water.

Damage scenarios and an onboard support system for damaged ships

  • Choi, Jin;Lee, Dongkon;Kang, Hee Jin;Kim, Soo-Young;Shin, Sung-Chul
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제6권2호
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    • pp.236-244
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    • 2014
  • Although a safety assessment of damaged ships, which considers environmental conditions such as waves and wind, is important in both the design and operation phases of ships, in Korea, rules or guidelines to conduct such assessments are not yet developed. However, NATO and European maritime societies have developed guidelines for a safety assessment. Therefore, it is required to develop rules or guidelines for safety assessments such as the Naval Ship Code (NSC) of NATO. Before the safety assessment of a damaged ship can be performed, the available damage scenarios must be developed and the safety assessment criteria must be established. In this paper, the parameters related to damage by accidents are identified and categorized when developing damage scenarios. The need for damage safety assessment criteria is discussed, and an example is presented. In addition, a concept and specifications for the DB-based supporting system, which is used in the operation phases, are proposed.

해수환경하에 노출된 선박용 타 재료의 전기화학적 및 캐비테이션 특성 평가 (Investigation on electrochemical and cavitation characteristics of rudder materials for ship in sea water)

  • 김성종;이승준
    • Corrosion Science and Technology
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    • 제10권3호
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    • pp.101-107
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    • 2011
  • Marine ships have played an important role as a carrier, transporting much more than 80% of all international trading, and marine transportation is an internationally competitive, strategic, and great national important industry. However, those marine ships have the characteristics such as voyage of long distance, large-volume and lower speed than the other carry system. Therefore, it is important to manufacture a larger and faster ship, however, the steel plates which are consisted with most of those ships has brought about many corrosion problems in sea water such as general corrosion, localized corrosion, cavitation and erosion corrosion etc.. Most hulls of the ships have been protected with paintings, sacrificial anode, marine growth prevention system, and impressed current cathodic protection methods against numerious corrosion problems mentioned above. However, these conventional methods are not very effective because the rudder of ships stern are exposed to very severe corrosive environment such as tides, speeds of ships, cavitations and erosion corrosion, etc.. In this study, electrochemical and cavitation characteristics was investigated for the rudder material of ship which is exposed to serious corrosive environment. As a result, it is considered that the optimum cathodic protection potentials of rudder material is the range of -0.6 V ~ -0.8 V(Ag/AgCl) in static seawater.

선박기인 CO2 저감을 위한 에너지효율 운항지표에 관한 연구 (A Study on the Energy Efficiency Operational Indicator for CO2 Reduction from Ships)

  • 최재성;노범석
    • Journal of Advanced Marine Engineering and Technology
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    • 제35권8호
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    • pp.1035-1040
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    • 2011
  • 본 논문에서는 IMO에서 논의 중인 운항선의 에너지효율지표에 대하여 연구를 수행하였다. IMO의 온실가스 저감을 위한 정책방안을 살펴보고 그 중 운항선에 대한 에너지효율지표를 분석하였다. 화물량에 대한 연료소비율 산정방법을 이용하는 에너지효율지표를 실제 운항선에 적용하여 결과를 분석하고 문제점을 제기하였다. 이를 바탕으로 엔진 부하에 대한 연료소비율을 이용하는 개선된 에너지효율지표를 제시하고 운항선에 적용하였다. 결과를 통해 개선된 에너지효율지표가 운항선에 대해 합리적인 이산화탄소 배출률을 정의할 수 있다고 판단하였다.

위상추정기 및 위상추적기를 갖는 버스트 QPSK 전송시스템 설계 (Burst QPSK Transmission System Design with Phase Estimator and Tracker)

  • 김승근;최영철;김시문;박종원;이덕환;임용곤
    • 한국음향학회:학술대회논문집
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    • 한국음향학회 2004년도 춘계학술발표대회 논문집 제23권 1호
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    • pp.183-186
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    • 2004
  • 본 논문에서는 수중 초음파 통신용 QPSK 버스트 수신기를 DSP시스템을 이용하여 구현하기위한 시스템 설계에 대하여 논한다. 본 논문에서 고려하는 시스템은 25kHz의 반송주파수를 사용하고, 심벌율은 5kHz이며, 데이터 전송율은 10,000bps이다. 송신기에서 심벌정보를 전송하기 위해 펄스성형필터를 거친 신호를 디지털 믹서기를 이용하여 디지털 영역에서 반송주파수 대역으로 신호를 변조한 후 200kHz로 샘플링하는 D/A변환기를 이용하여 전송 아날로그 신호를 생성한다. 수신기에서는 수신 신호를 디지털로 처리하기 위하여 100kHz로 free running하는 A/D 변환기를 이용하여 수신 데이터를 얻는다. 수신기에서는 32심벌 길이의 프리앰블을 이용하여 프레임 동기를 찾음과 동시에 개략적인 심벌시간 동기와 위상편이를 추정한다. 추정한 위상편이값은 2차 PLL (phase-looked loop)의 초기값으로 사용하여 위상 추적을 수행하는 전송 시스템이다. 또한, 된 논문에서는 실해역 전송 시험 테이터를 통하여 조류의 변화에 의해 발생하는 Doppler 편이를 보상하기 위하여 PLL이 필수적으로 필요함을 보인다.

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심해저 채광로봇 'MineRo' 망간단괴 파쇄 성능시험 (Performance Test for the Manganese Nodule Crushing Equipment of the Deep Seabed Mining Robot 'MineRo')

  • 성기영;민천홍;김형우;이창호;오재원;홍섭
    • Ocean and Polar Research
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    • 제36권4호
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    • pp.455-463
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    • 2014
  • This paper presents data from performance tests carried out to assess a manganese nodule crusher. Manganese nodules should be crushed into smaller pieces in order to assure the slurry flow of the lifting system. Both artificial nodules and real manganese nodules are used to evaluate nodule breaking ability of the crusher. The crushing performance of the crusher depends on the flow rate and pressure of the power transmission device. The size of the crushed manganese nodules also depends on the shape of the crushing drum. In this paper, several comparative tests are carried out to evaluate and improve the crushing performance and find the optimal design point of the crusher.