• 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.

• 한국항해항만학회지
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• 제38권6호
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• pp.593-600
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• 2014

실시간 해수유동 정보를 중심으로 신조선 선박의 실선시운전에서 활용될 수 있는 정보 제공 시스템을 개발하였다. 본 시스템에서는 실선시운전 지원 정보로서 특정시간 해수유동의 공간분포를 예측하여 제공하며, 특정지점 해수유동의 시계열 변동을 예측하여 제공한다. 또한 본 시스템은 실선시운전에 있어 시험선박 운항경로에서의 해수유동 정보 및 선속 손실정보를 제공하기 위하여 GPS와 연결할 수 있는 기능을 가지고 있으며, 이러한 기능을 이용하여 실선시운전시 자동으로 운항경로상의 해수유동 실시간 정보 및 해수유동에 의한 선속손실을 계산하여 제공한다. 실선시운전 중의 정보 제공 이외에, 본 시스템에서는 특정한 시험시간과 시험경로에 대해 선속손실을 예측하여 제공함으로써 최적의 시험시간 및 시험경로를 계획할 수 있도록 지원하는 기능도 가지고 있다. 본 연구에서 개발된 실선시운전을 위한 실시간 해수유동 예측시스템은 효율적인 시험계획과 정확한 해역특성 파악을 지원할 뿐 아니라, 실선에 탑재되어 시험 중에 요구되는 다양한 정보를 제공한다.

• 한국수산과학회지
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• 제55권4호
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• pp.443-448
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• 2022

Two long-term feeding trials were conducted to compare the effects on survival and growth of juvenile sea cucumber Apostichopus japonicus of experimental diets containing corn distillers dried grains with solubles, Squid Sepioteuthis sepioidea liver meal, and brown fish meal with a commercial die. In both first and second trials, two experimental diets and one commercial diet were assessed. After a 45-week feeding period in trial 1, survival did not differ significantly among groups. The final mean weight of sea cucumbers fed either experimental diet was significantly higher than that of sea cucumbers fed the commercial diet. After a 15-week feeding period in trial 2, survival and final mean weight of sea cucumbers fed either experimental practical diets was significantly higher than that of sea cucumbers fed the commercial diet. It was concluded that the experimental diets formulations can be used as a practical diet, and inclusion of corn distillers dried grains with solubles, squid liver meal, and brown fish meal can improve the growth of juvenile sea cucumbers.

• 한국항해항만학회지
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• 제29권7호
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• pp.595-601
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• 2005

The IMO manoeuvrability standard was established for preventing sea accidents such as collisions and strandings due to the lack of manoeuvrability. The standard of ship manoeuvrability enforced by resolution MSC.l37(76) has been applied to vessels of 100m or more in length and all chemical tankers and gas carriers regardless of the length, which were constructed on or after 1 July 1994. The IMO manoeuvrability standard is able to be divided into three kinds as followings; (1) Turning capability standard: Estimated values in design stage are to be certified by turning circle test of the actual vessel. (2) Course keeping quality standard : Estimated values in design stage are to be certified by 10 deg. and 20 deg. zig-zag tests of the actual vessel. (3) Shortest stopping distance standard : Estimated value in design stage is to be certified by the shortest stopping distance tested by the actual vessel. In this paper, the authors verified the criteria of IMO manoeuvrability standard comparing them with the values resulted from sea trial tests of various kinds of actual vessels and examined separately the validity of all criteria of the standard.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2005년도 추계학술대회지
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• pp.27-33
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• 2005

The IMO manoeuvrability standard was established for preventing sea accidents such as collisions and strandings due to the lack of manoeuvrability. The standard of ship manoeuvrability enforced by resolution MSC.137(76) has been applied to vessels of 100m or more in length and all chemical tankers and gas carriers regardless of the length, which were constructed on or after 1 July 1994. The IMO manoeuvrability standard is able to be divided into three kinds as followings; (1) Turning capability standard: Estimated values in design stage are to be certified by turning cir치e test q the actual vessel (2) Course keeping quality standard: Estimated values in design stage are to be certified by 10 deg. and 20 deg. zig-zag tests of the actual vessel. (3) Shortest stopping distance standard: Estimated value in design stage is to be certified by the shortest stopping distance tested by the actual vessel. In this paper, the authors verified the criteria of IMO manoeuvrability standard comparing them with the values resulted from sea trial tests of various kinds q actual vessels and examined separately the validity of all criteria of the standard.

• 한국수산과학회지
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• 제47권6호
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• pp.796-800
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• 2014

A feeding trial was conducted to investigate the growth and body composition of juvenile sea cucumber Apostichopus japonicus in integrated culture with abalone Haliotis discus hannai or rockfish Sebastes schlegeli. Triplicate groups of sea cucumber averaging $1.2{\pm}0.05g$ were cultured alone or with abalone or rockfish for 12 weeks. Survival of sea cucumber was not affected by co-culturing (P>0.05). Weight gain of sea cucumber cultured with rockfish was significantly higher than that of sea cucumber cultured alone (P<0.05), and did not differ from that of those cultured with abalone (P>0.05). These findings indicate that co-culturing sea cucumber with rockfish effectively improves the growth of sea cucumber.

• 한국항해항만학회지
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• 제44권6호
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• pp.453-459
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• 2020

선박의 해상 시운전 중 속도성능시험은 선박의 속도를 입증하기 위한 중요한 시험항목 중 하나이다. 국제표준화기구에서는 2015년 시운전 속도성능시험에 관한 표준 가이드라인을 제정한 바 있다. 일반적인 해상상태에서는 바람과 파도등 환경적 외란의 영향이 언제나 존재하므로, 정확한 전달동력을 추정하기란 불가능 하다. 또한 외란의 영향으로 최근 개발되고 있는 에너지 절감장치의 개선효과를 정확히 평가하는 것도 쉽지 않다. 본 연구에서는 몬테카를로 시뮬레이션을 이용하여 공기윤활시스템을 장착한 선박의 동력 절감량에 관한 불확실성 해석을 수행하였다. 그 결과 공기윤활시스템 가동으로 3.2%의 동력이 절감되었으며, 절감된 동력의 확장불확도는 95% 신뢰수준 (k = 2)에서 약 ± 2.7 % 범위를 갖는 것으로 나타났다.

• 한국음향학회지
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• 제42권3호
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• pp.169-180
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• 2023

수중음향통신의 성능은 다중경로 전달과 도플러 확산에 크게 영향을 받는다. 본 논문은 다중경로 전달 환경에서 강인한 기존의 Sweep Spread Carrier(SSC) 기법을 변형하여, 새로운 통신기법인 Triangle Spread Carrier(TSC) 기법을 제안한다. 제안한 TSC 기법은 상승-처프와 하강-처프 신호가 반복되는 반송파를 갖는 형태이며, 각각의 상관함수 특성을 활용하여 수신 신호의 도플러 천이 주파수를 추정하고 보정한다. 제안된 TSC 기법의 성능을 입증하기 위하여 수중 채널 시뮬레이터를 이용한 모의실험과 동해에서 수행된 해상실험을 결과를 제시한다. 해상실험 결과 추정된 도플러 천이 주파수만을 이용하여 복조하였을 때 비부호화 된 비트 오류율은 최대 0.194였지만, 제안한 방법을 적용하였을 때 비부화화된 비트 오류율이 0.001로 감소하였다.

• 한국수산과학회지
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• 제37권5호
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• pp.400-404
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• 2004

Growth performances of the selected and the non-selected red sea bream (Pagrus major) lines were evaluated up to marketable size. The offspring were mass-produced either from the selected line (the fourth generation of broods from mass selection) or the non-selected line (the second generation of wild broods). Early (59 to 103 days old, trial I) and late growth performances (4 to 24 months old, trial II) were evaluated based on communal rearing in land-based tanks and sea cages, respectively. In trial I, the selected line exhibited significantly higher values in both weight gain (WG) and specific growth rate (SGR) when compared to those observed in the non-selected line (P<0.05). In trial II comprising of three growth phases (4-9, 9-16 and 16-24 months old), selected line showed only slightly improved in WG and SGR at the beginning two growth phases (4-9 and 9-16 months old) (P>0.05), however, displayed significantly higher values at the last growth phase (16-24 months old) (P<0.05). Overall WG and SGR throughout the experiment (4-24 months) were also significantly higher in the selected line than the non-selected line (P<0.05). Consequently, mean body weight of the selected line at 24 months old was 1.4-fold (40.8{\%}\;increased) as compared to that of the non-selected line. This present result indicates that mass selection of this species against the growth traits might be quite effective, and the present advance has important Implication in the productivity enhancement of red sea bream aquaculture.

• Journal of Advanced Marine Engineering and Technology
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• 제15권4호
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• pp.29-45
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• 1991

Lip type stern tube sealing systems have used in almost all the middle or large ships which are being constructed in these days. It seems that the pressure fluctuation of the seal ring interspace, the cross-section profile and the materials quality of the seal rings have great effects on the sealing fuction of this sealing system. In this paper, the mechanical movement of lip seal ring which plays the most important role in stern tube sealing system and the possibility of leakage caused by pressure fluctuation are studied by theory and experiment. Using the finite element method for the axi-symetric object which receives the torsional load, the displacement and stress analysis of the seal rings, and also the possibility of crack occurance is checked by theoretical analysis. If the force which seal ring lip periphery receives is too small, there will be the possibility of leakage caused by the pressure fluctuation of the seal ring interspace, and if this force is too large, the frictional force between the seal ring and the liner will become problematical. The possibility of leakage caused by hardening of seal ring materials and creep phenomena of tested seal rings are also examined. The trial seal rings were designed and manufactured using the program of displacement and stress analysis developed in this study and the experimental apparatus to test the trial seal rings was also designed and manufactured. This trial seal rings were fitted in the experimental apparatus which was made in the same form as an actual stern tube. The one side of this apparatus was filled with sea water and the other side of it was filled with the lubricating oil. The leakage of oil and sea water was checked and the temperature was measured, rotating the propeller shaft at the constant velocity by D.C. motor. It was proved that the trial seal rings made in Viton rubber functioned excellenty but the trial seal rings made in N.B.R. rubber had problem in its durability.