• 대한조선학회논문집
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• 제46권6호
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• pp.553-561
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• 2009

This paper presents the results of prediction of maneuverability of KCS by CPMC captive model test. The CPMC(Computerized Planar Motion Carriage) with captive model test equipment is installed at Ocean Engineering Tank of MOERI. KCS is the container ship which was open to the world by MOERI. And the test results for the prediction of maneuverability were presented by NMRI in Japan. The research results about the maneuverability of KCS were presented at SIMMAN 2008 Workshop in Denmark. The results of test and simulation of this paper are compared with the results of simulation by MOERI using test results of NMRI and simulation results by NMRI.

• 대한조선학회논문집
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• 제60권2호
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• pp.76-85
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• 2023

The present study aims to review the wave pattern resistance analysis method suggested by the International Towing Tank Conference. From the experimental database of a container carrier ship model, the wave pattern measurement and resistance test results are utilized. The wave pattern resistance at the design Froude number is obtained to be compared with the wave making resistance of experiments. Wave pattern resistance is lower than wave making resistance by 1978 ITTC and uniform regardless of transverse location of wave cut. The method is also applied to the wave height field by Computational Fluid Dynamics (CFD) analyses with Froude number variation. Although numerical damping suppressed waves in downstream, waves around the hull and wave pattern resistance are properly predicted.

• 한국식품위생안전성학회지
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• 제4권2호
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• pp.103-108
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• 1989

대표적 야채 가공제품의 하나인 양송이 통조림을 제조하는 공장을 규모별로 선정하여 용수와 원료의 오염도를 측정하고 세척, 자숙 및 경과시간별 총균수의 증감을 관찰하여 야채류 가공 시 공정설정에 필요한 미생물학적 기초자료를 얻었다. 이들 공장에서 사용하는 용수의 총균수는 10ml당 $10^{2}CFU$ 정도였으며 세척 탱크에 받아놓는 세척용수에는 이미 총균수가 10-100배 증가하는 현상을 보였다. 원료 양송이 중 총균수는 $10^{5}-10^{6}CFU/g$ 이었고 이를 세척하는 경우 양송이 1톤당 세척수를 2.3톤까지 사용하는 경우 세척효과가 있으나 1.8톤 이하 사용시는 오히려 미생물 오염도를 높이는 결과를 초래하였다. 자숙에 의하여 균수는 50-5000 CFU/ml으로 감소하였고 자숙 후 $16^{\circ}C$ 물에 3시간 정도 방치하는 것은 미생물 증식에 큰 영향을 주지 않았으나 액즙(8$0^{\circ}C$)을 주입후 살균개시 전까지 방치함에 따라 균수는 초기 $84{\times}10^{4}CFU/ml$에서 3시간 후 $20{\times}10^{7}CFU/ml$로 증가하였다.

• 대한조선학회논문집
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• 제28권2호
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• pp.40-51
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• 1991

캐비테이션 특성이 우수하고 추진효율이 높은 콘테이너선용 프로펠러를 설계하기 위하여 새로운 날개단면(KH18)을 이용한 프로펠러 설계법을 제안하였다. KH18 단면은 캐비테이션 초생곡선(Cavitation-free bucket diagram) 및 양력-항력곡선(Lift-drag curve)에서 폭이 넓어 불균일한 선미후류에서 작동되는 선박용 프로펠러의 날개 단면으로 적당하리라 판단되었다. 새로운 날개 단면을 이용한 콘테이너선의 프로펠러 설계를 위하여 양력면이론을 사용하였다. 프로펠러 설계시 코오드 방향 부하분포를 설계변수로 선택하여 5개의 프로펠러를 설계하였고, 단면 변화의 영향을 비교하기 위하여 NACA형 단면을 갖는 프로펠를 설계하여 예인수조 및 캐비테이션 터널에서 모형시험을 수행하였다. 모형시험 결과 코오드 방향 부하분포가 프로펠러 반경의 70% 내부에서는 날개 앞날의 부하가 적고 그 외부에서는 날개 앞날부하가 상대적으로 큰 코오드방향 부하분포를 갖는 프로펠러(KP197)가 NACA 단면을 갖는 프로펠러에 비하여 추진효율은 1% 향상되었고 캐비테이션 발생양은 30% 감소하였으며 선체변동압력은 9%감소하였다. 새로운 날개단면을 갖는 프로펠러의 캐비테이션 특성이 우수함을 고려하여 낱개 전개면적비를 감소시킨다면 더 많은 추진효율 증가를 기대할 수 있으리라 판단된다.

• 수산경영론집
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• 제29권2호
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• pp.111-141
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• 1998

Why are auctions so prevalent in fisheries fields\ulcorner One answer is, perhaps, that fisheries products have no standard value. The price of any catch of fish (at least of fish destined for the fresh fish market) depends on the demand and supply conditions at a specific moment of time, influenced by prospective market developments and prices must be remade for each transaction. There are various auction schemes including written-bid method in Korea. It is difficult to make decision the application of auction selling in market distribution. One reason is the absence of adequate data on which to base firm statements. There is very little precise information about the relative volume handled by auction scheme as compared with other sales schemes Because of the paucity reliable data, one must depend largely on qualitative in attempting to above this problem. This paper is designed to examine which auction scheme is more efficient as a economic tool by introducing the three auctions, as samples, utilized in Koheung peninsula. Koheung coast with abundant fisheries resource, locates on the Middle-South part in Korea and has three auction firm operating by fisheries cooperatives. fur selling of dry fish included sea weed, live fish and fresh fish respectively, As a result, 1 found that there are three interesting auction schemes as follow : 1. More than one winners are selected as buyers. The highest bidder can at first get fishes he wants to buy, second winner can get surplus fishes after the highest bidder employes one's privilege with the highest pay, and next winner would be a buyer if fishes would be left in sequence after being sold with higher price. Every fisherman can sell one' s fishes with equal unit price if he delivery it to the winner within one day. Therefore, all the vendors feel they are equal members of fisheries cooperation. 2. Written-bid pricing on the cover of handy book. It is easy to write and to erase the figure more than on the small black board, and is convenient also to keep in the pocket. 3. Auctioning on the fixed platform with fixed fish tank is a very fast auction scheme in spite of short displaying time. Auctioneer presides bidding at one place on the fixed platform, instead of moving, vendors should carry a container of live fishes in the fish tank into showing table in front of would-be buyers and auctioneer. Although the applicability of the auction system to a marketing problem depends in part on subjective considerations by those making decision, basically it is a matter of comparative economic efficiency. In general, if the scheme maximizes returns in relation to the effort expanded by both buyers and sellers, it will be utilized. If it does not, a more efficiency may take place over a period of time, but, even more important, those making decisions may become aware of the potentialities of new schemes. Therefore, in order to applicate the three interesting auction schemes introduced in this paper to other fisheries market, it is necessary not only to analyze many other auction schemes but also to compare the economic efficiency those schemes utilizing in other fisheries market.

• 대한조선학회논문집
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• 제29권1호
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• pp.71-80
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• 1992

국제수조회의(ITTC) 내항성분과에서 회귀현상(rare event)레 대한 시험기법 확립 및 계측기간 결정을 목적으로 19차 ITTC 내항성분과의 공동사업으로 갑판침수 계측시험을 수행한 바 있다. 본 논문에는 공동연구에 참여한 수조시험연구회(KTTC)의 두 회원인 해사기술연구소(KRISO)와 현대선박해양연구소(HMRI)의 실험방법 및 결과를 비교 검토하였다. 선수상대운동과 갑판침수 사이의 상관관계 및 Poisson process에 근거한 계측시간의 추정에 촛점을 두어 결과를 고찰하였다. 동일한 특성을 갖는 입사파에 대해 계측된 갑판침수 빈도수는 두 기관 모두 계측시마다 큰 차이를 보였으며 이는 일반적인 선체운동 계측 보다 더 많은 계측시간이 필요한 것을 의미한다. 선수상대운동과 갑판침수사이의 상관관계는 선수형상, 선속 및 해상상태에 따라 달라지며 본 공동연구의 실험 조건하에서는 (유의파고 7.88m, 선속 22.15노트) 둘 사이의 상관관계가 매우 높은 것으로 나타났다. 또한 갑판침수 현상의 통계적 특성은 Poisson process로 해석될 수 있음을 보였다.

• Journal of Advanced Marine Engineering and Technology
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• 제39권9호
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• pp.918-922
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• 2015

선박으로부터 배출되는 오염원과 온실가스에 대한 국제적 규제가 점점 더 강화되어 감에 따라, 액화 천연 가스를 선박의 연료로 사용하는데 대한 관심이 높아져 가고 있다. 본 연구는 액화 천연 가스 연료 선박에서 사용되는 두 가지 방식의 연료 가스 공급 장치에 대하여 폭발 잠재 위험 분석을 수행하였다. 8500 TEU 급 컨테이너 선박을 목표 선박으로 선정하여, 액화 천연 가스 저장 탱크를 설계하였고 각 연료 공급 방식의 운전을 위한 압력 조건을 가정하였다. 누출공의 크기를 세 개의 범주로 분류하여, 각 누출공 크기 범주에 대한 누출 빈도를 산출하였고, 대표 누출공의 크기와 누출량을 추산하였다. 방출률의 증가와 누출 빈도는 역비례 관계를 보였으며, 펌프 방식 연료 공급 장치에서는 누출 빈도가 높게 나타났고, 가압 방식 연료 공급 장치에서는 방출률이 높게 나타났다. 전산 유체 역학 시뮬레이션을 통하여 폭발 잠재 위험 분석을 수행하고 각 연료 공급 장치에 대한 결과를 비교하였다.

• 한국항해학회지
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• 제13권2호
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• pp.23-36
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• 1989

Marine casualities in the high sea are mainly classified into the breakage of hull and capsize , of which the latter occurs frequently to a small craft and container vessels by extreme rolling. The aim of this study is to develop shiphandling techniques for the prevention of ship's large rolling by way of evaluating dangerous degree of rolling in heavy weather. In this study, rolling motion is analized by using statistical method as follow : (1) 8 sample ships is presented for calculation. (2) Analized sea state are Beaufort scale 7 and 10 (wind velocity 30kts and 50kts respectively) and significant wave height is put as 5.2m and 11.2m. (3) The formula recommended by International Towing Tank Conference (ITTC) is used to calculated the wave spectrum. The results of this study are as follow : The results of this study are as follow : (1) Most of the vessels with beam of 20 meters or less was found to be capized in the waves abeam under the sea condition of Bearfort scale7(30kts). (2) For the vessels range 20m to 30m was found safe under the sea conditions of Bearfort scale 7(30kts) and imminent danger under the sea condition of Beaufort scale 11(50kts). (3) It is proved that any vessel could be capsized by heavy rolling regardless of vessel's size whenever the motion is synchronized with waves abeam. This study concludes that the navigator, especially at night , must anticipate the exact wave direction, referring to the wether report and coastaline, not to lay the vessel in the serial wave abeam.

• 대한조선학회논문집
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• 제47권2호
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• pp.163-177
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• 2010

This article examines hydrodynamic characteristics and speed performances of a ship attached with a full spade and a twisted rudder based on a computational method. For this study, a 13,100 TEU container carrier is selected. The turbulent flows around a ship are analyzed by solving the Reynolds-averaged Navier-Stokes equation together with the application of Reynolds stress turbulence model. The computations are carried out at the conditions of rudder, bare hull, hull-rudder and hull-propeller-rudder. An asymmetric body-force propeller is applied. The speed performance is predicted by the model-ship performance analysis method of the revised ITTC'78 method. The hydrodynamic forces are compared in both rudder-open-water and self-propulsion conditions. The flow characteristics, the speed performance including propulsion factors and the rudder-cavitation performance are also compared. The model tests are conducted at a deep-water towing tank to validate the computational predictions. The computational predictions show that the twisted rudder is superior to the full spade rudder in the respect of the speed and the cavitation performances.

• 한국해양공학회지
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• 제29권6호
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• pp.418-426
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• 2015

Recently, shipping operators have been making efforts to reduce the fuel cost in various ways, such as trim optimization and bulb re-design. Furthermore, IMO restricts the hydro-dioxide emissions to the environment based on the EEDI (Energy Efficiency Design Index), EEOI (Energy Efficiency Operational Indicator), and SEEMP (Ship Energy Efficiency Management Plan). In particular, ship speed is one of the most important factors for calculating the EEDI, which is based on methods suggested by ITTC (International Towing Tank Conference) or ISO (International Standardization Organization). Many shipbuilding companies in Korea have carried out speed trials around the Korea Straits. However, the conditions for these speed trials have not been exactly the same as those for model tests. Therefore, a ship’s speed is corrected by measured environmental data such as the seawater temperature, density, wind, waves, swell, drift, and rudder angle to match the conditions of the model tests. In this study, fundamental research was performed to evaluate the ship resistance performance due to changes in the water temperature and salinity, comparing the ISO method and numerical simulation. A numerical simulation of a KCS (KRISO Container ship) with a free-surface was performed using the commercial software Star-CCM+ under three conditions that were assumed based on the water temperature and salinity data in the Korea Straits. In the simulation results, the resistance increased under low water temperature & high salinity conditions, and it decreased under high water temperature & low salinity conditions. In addition, the ISO method showed the same result as the simulation.