• 한국산학기술학회논문지
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• 제21권11호
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• pp.420-426
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• 2020

본 연구에서는 효율적인 함정 시운전을 위하여 빅데이터 기법인 워드 클라우드를 활용하여 한미 해군의 시운전 목적과 주안점을 다각적으로 파악하여 다음과 같은 결과를 도출하였다. 첫째, 한미 해군 시운전 종목을 키워드 클렌징을 통해 추출된 단어를 비교한 결과 한국 해군은 시운전을 단일 장비에 대한 시험의 개념으로 수행하며, 미 해군은 시스템에 초점을 둔 통합 시운전을 진행한다는 것을 알 수 있었다. 둘째, 한미 해군 시운전 연관도 분석 결과 약 66.6%가 유사한 항목으로 분석되었으며, 그중 2종목 이상 중복된 종목이 112종목이었다. 한국 해군 시운전 종목 252종목 대비 44%가 중복된 종목으로 미 해군 시운전 종목으로 통합시 89종목(전체 35%)이 축소 가능하다고 분석되었다. 함정은 여러 장비가 동시 다발적으로 작동하는 복합 시스템이다. 현재 한국 해군 시운전과 같이 개별 장비의 기능, 성능 확인에 중점을 두고 수행하는 것은 시운전 대상이 지나치게 많아져 시운전 기간이 증가하게 된다. 또한, 그로 인한 일정 및 평가비용 증가로 필요한 예산이 필연적으로 증가한다. 향후 미 해군의 시운전과 같이 통합 시스템적인 평가를 통한 효율적이면서 정확한 시운전을 위하여 추가적인 연구가 필요하다고 판단된다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.396-404
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• 2021

It is important to verify that the contracted speed-power performance of a ship is satisfied in sea trials. International Organization for Standardization (ISO) has published the procedure for measuring and assessing ship speed during sea trials. The results obtained from actual sea conditions inevitably include various uncertainty factors. In this study, double run tests were performed on one container ship to analyze the uncertainty of sea trial on three maximum continuous rating conditions. The uncertainty factors and scale of uncertainty were examined based on the measured raw data during sea trial. The results indicate that the expanded uncertainty for ideal power performance is approximately ±1.4% at 95% confidence level (coverage factor k = 2) and most of the uncertainty factors were because of the shaft power measurement system.

• 한국해양공학회지
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• 제12권1호
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• pp.135-142
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• 1998

In this study, the frequency transfer function of motions are predicted from the result of a full-scale seakeeping trials. Because the real sea has the characteristics of multi-directional waves,we compare the results in the one directional waves with ones in the directional waves. For calculation of the frequency transfer function in the directional waves, Takezawa's inverse estimation method was introduced and the frequency ranges were divided into three parts in order to consider following seas. The full-scale seakeeping trials was executed in the south sea of Korea using the stern trawler. Those results show that analysis method of the multi-directional waves is more reliable than that of one directional waves, and confirm the possibility of applying this method to the full-scale seakeeping trials.

• Fisheries and Aquatic Sciences
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• 제16권3호
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• pp.211-220
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• 2013

A shaking motion could be used to improve fish escapement from a cod-end net by creating a sieving effect over the swept volume or by disturbing the optomotor response of the fish. In this study, a perpendicular shaking motion was generated in a towed cod-end net by a circular canvas attached to the end of the codend, which formed a biased cap-like shape. This concept was tested by using a model in a flow tank and by towing a prototype cod-end during sea trials. For the model tests, the amplitude of the shaking motion was $0.6{\pm}0.1$ times the rear diameter of the cod-end, and the period of the shaking motion was $2.6{\pm}0.1$ s at a flow velocity of 0.6 or 0.8 m/s. In the sea trials, the amplitude was $0.5{\pm}0.2$ times the rear diameter of the cod-end, and the period of the shaking motion was $7{\pm}4$ s at towing speeds of 1.2 or 1.7 m/s. Thus, the shaking amplitude during the sea trials was equal to or less than that observed in the tank tests, and the shaking period was twice as long. The shaking motion described by the amplitude and period could be an effective means to stimulate fish escapement from cod-end during fishing operations considering the response of the fish.

• 대한조선학회논문집
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• 제46권6호
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• pp.603-610
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• 2009

Ice load is one of the important design parameters for the construction of icebreaking vessels. In this paper, the design ice load prediction for the icebreaking vessels under normal operating condition in ice-covered sea is discussed. The ice loads under normal operating condition are expected from sea trials in moderate ice conditions. In this sense the extreme ice loads during heavy ramming or accidental collision are not considered. Current study describes the global ice load on the hull of the icebreaking vessels. Available ice load data from full-scale sea trials are collected and analyzed according to various ship-ice interaction parameters including displacement, stem angle, speed of a ship and flexural strength and thickness of sea ice. The ice load prediction formula is compared with the collected full-scale sea trials data and it shows a good agreement.

• 대한조선학회논문집
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• 제51권3호
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• pp.254-258
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• 2014

Field trial in ice-covered sea is one of the most important tasks in the design of icebreaking ships. To correctly estimate ice load and ice resistance on ship's hull, It is essential to understand the material properties of sea ice during ice field trials and to perform the proper experimental procedure by gathering sea ice data. A measurement of sea ice properties was conducted during February and March of 2012 with the Korean Icebreaking research vessel "ARAON" in the Amundsen Sea, Antarctica. This paper describes a test procedure to obtain sea ice data which provide basic information to estimate ice loads and icebreaking performance of the ship. The data gathered from sea ice field trials during the 2012 Antarctic voyage of the ARAON includes ice temperature/salinity/density and the compressive/flexural strength of sea ice. This paper analyses the gathered Antarctic sea ice material properties comparing with the previous data obtained during ARAON's Arctic and Antarctic voyages in 2010.

• 한국어류학회지
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• 제20권3호
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• pp.173-178
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• 2008

black sea bass 치어(이하 치어라 칭함)의 기질 선택성을 수조 내부의 바닥을 굴 껍질 관련 기질과 모래 기질을 덮어 이등분 한 원형수조(1.5 m 직경${\times}$0.4 m 깊이)에서 조사하였다. 실험어는 1개체를 수조에 넣는 단독수용과 5개체를 넣는 그룹으로 하였다. 모든 치어의 기질 선택행동 실험은 20분간 비디오에 녹화하여 모니터 상에서 관찰하였고 수조 내에서 치어의 위치와 각 기질에서 체류한 시간을 기록하였다. 굴 껍질 관련 기질에서 치어가 보낸 평균시간은 1개체 수용구에서 $18.1{\pm}2.0$분과 5개체 수용구에서 $17.5{\pm}1.7$분으로 나타났다. 한편, 모래기질 위에서는 1개체 수용구에서 $2.0{\pm}1.0$분과 5개체 수용구에서 $2.5{\pm}1.7$분으로 나타났다. 1개체와 5개체의 치어로 수행한 실험 모두에서 모래 기질보다는 굴 껍질 관련 기질에 대해 유의한 선택성을 나타냈다(paired t-test, P<0.05). 굴 껍질 관련 기질 아래 체제시간은 1개체 수용구에서 $16.6{\pm}2.0$분과 5개체 수용구에서 $10.7{\pm}2.3$분으로 나타났다. 굴 껍질 관련 기질 사이를 이동한 횟수는 1개체 수용구에서 $1.1{\pm}1.0$회와 5개체 수용구에서 $11.5{\pm}3.1$회로 나타났다. 치어는 1개체 수용구보다는 5개체 수용구에서 굴 껍질 관련 기질 아래 머무는 시간이 유의하게 적고, 또한 움직임이 많은 것으로 나타났다(paired t-test, P<0.05). 은신처 확보를 위한 치열한 경쟁으로 인해 5개체 수용구의 치어가 굴 껍질 관련 기질 아래 머무는 시간이 적고 움직임이 많은 것으로 추측된다.

• 해양환경안전학회지
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• 제26권3호
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• pp.269-276
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• 2020

Sea trial tests are necessary to verify speed-power performance, and are an import contract between ship owners and shipyards. The International Organization for Standardization (ISO) published ISO 15016:2015, which specifies the correlation method between model and full-scale ships. The results of sea trials have been questioned because of the uncertainty of speed and power measurements, especially when sea conditions differ from ideal calm water conditions. In this paper, such uncertainties were investigated by utilizing the standard speed-power trial analysis procedure defined in ISO 15016:2015 through Monte Carlo simulations. It was found that the expanded uncertainty of the delivered power (P_Did) at 95 % confidence interval (k = 2) was ±1.5 % under 75 % MCR conditions.

• 한국해양공학회지
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• 제26권1호
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• pp.1-8
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• 2012

To correctly estimate ice load and ice resistance for a ship's hull, it is essential to understand the material properties of sea ice during ice field trials and to use the proper experimental procedure for gathering ice strength data. The first Korean-made icebreaking research vessel (IBRV), ARAON, had her second sea ice trial in the Arctic Ocean during July and August of 2010. This paper describes the test procedures used to properly obtain sea ice strength data, which provides the basic information on the ship's performance in an ice-covered sea and can be used to estimate the correct ice load and ice resistance on the IBRV ARAON. The data gathered from three sea ice field trials during the Arctic voyage of the ARAON includes the ice compressive strength, flexural strength, and failure strain of sea ice. This paper analyzes the gathered sea ice data in comparison with data from the first voyage of the ARAON during her Antarctic Sea ice trial in January 2010.

• 대한조선학회논문집
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• 제42권5호
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• pp.458-465
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• 2005

Sensitivity Analysis(SA) is used to predict how the model response varies according to changes in the model parameters. With SA, confidences in models which are developed to approximate certain processes and their predictions can be increased. The influences of hydrodynamic coefficients on the prediction of manoeuvrability are examined by SA of direct method. The equations of motion used are the standard equations of motion for submarine(Gertler 1967), and submerged bodies with three different appendages are considered. Through numerical simulations of three kinds of sea trials, the sensitivities of motions to hydrodynamic coefficients are found. Changes of sensitivities during trials are found to be highly dependent on the actuator scenarios and geometry of submerged body.