• Journal of Animal Science and Technology
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• v.46 no.1
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• pp.49-54
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• 2004

Effects of low quality roughage sources on duration and frequencies of rumination and chewing in Hanwoo steers were determined, Animals were fed three diets; concentrate+rice straw(SO:SO), concentrate+ rice straw + popped rice hull(SO:3S: IS) and concentrate+ rice straw+ground rice hull(SO:3S: IS) to compare both rice straw alone and combination with rice hull. Eating and ruminating time of steers fed concentrate+ rice straw(SO:50), concentrate+ rice straw + popped rice hull(50:35:15) and concentrate + rice straw + ground rice hull(50:3S:15) were 78.8 and 338.4minlday; 98.0 and 362.5minlday, and 160 and 519.2min/day, respectively. When steers were fed popped rice hull and ground rice hull, time spent for both eating and ruminating was significantly increased(p <0.05). When steers fed popped and ground rice hull, number of ruminating chews and number of chews per rumination time were significantly decreased(p<0.05). The number of rumination boli and boli per rumination time had significantly decreased(p<0.05), but chewing time per boli, number of chew'S per bolus were significantly increased(p

• Korean Journal of Agricultural Science
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• v.38 no.1
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• pp.95-100
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• 2011

In the present study, effects of autohydrolysis treatment on the properties of rice hull were investigated. Two temperature condition such as $160^{\circ}C$ and $180^{\circ}C$ and thee treatment time such as 15 min, 30 min and 45 min were applied for autohydrolysis treatment. The pH of extract after autohydrolysis treatment decreased as increasing of the temperature and the treatment time. The ash content and the lignin content of rice hull were not decreased by the autohydrolysis treatment. The structure of rice hull after autohydrolysis treatment became more weak, the better efficiency of the fiberization with PFI-Mill was shown for the autohydrolysis treated rice hull with the higher temperature and the longer treatment time.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.2
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• pp.431-441
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• 2014

The effects of hull-girder vibration on the fatigue strength of a Post-Panamax container ship are discussed in the present paper. Firstly, the short-term sea states are categorized according to the occurrence probability of each sea state. Time histories of hull-girder stress in short-term sea states are calculated by means of a nonlinear simulation code of ship response assuming that the hull-girder is rigid and flexible. Then, the calculated stress peaks are processed by the rainflow counting method, where two different counting procedures are used based on the considerations of crack propagation behaviors. Finally, the fatigue damage in life time of the ship in each categorized short-term sea state is estimated by means of Miner's rule. Based on the calculated results, the effects of hull-girder vibrations on the fatigue damage are clarified by disaggregated damage from short-term sea state.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.7
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• pp.966-973
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• 2011

Power distribution onboard vessel is typically configured as ungrounded system due to the ability to continuously supply electric power even when an earth fault occurs. The impedance connections between 3 phase power lines and hull cause the line-to-hull voltages to become unstable and increased in case the impedances are unbalanced, bringing the situation susceptible to electric shock and deterioration of insulation material. Also the line-to-hull voltage can reach to a certain maximum value in the steady state depending on the distributed capacitances and grounding resistances between lines and hull. This study suggests how to find and calculate the maximum line-to-hull voltage in view of magnitude and phase angle based on the vector diagram.

• Korean Journal of Computational Design and Engineering
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• v.20 no.3
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• pp.281-290
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• 2015

The specific goal of the SMS (Ship Management System) is to increate ship safety and decrease maintenance fee. Equipment of ship is managed by PMS (Planned Management System), subsystem of SMS. But hull has not managed by ship manager. So, the Classes have developed the system for hull maintenance. Recently, the ship maintenance system has been developed for satisfying operator's requirements such as managing maintenance data as integrated platform, intuitive manipulation and design for ease of use. To reflect such requirement, 3D Model based maintenance system was introduced for ship in operation stage. Hull items that have to be inspected, repaired, replaced, are stored in integrated data platform with drawing, reports, and etc. and completely linked to 3D product Model. This system is specially developed for measurement and maintenance of hull thickness.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.4
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• pp.1-7
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• 2003

Large Passenger Ferry has been delivered with a tendency of high speed since 1990´s. More than 50 ferries that exceed 25 knots in service speed are operating or under construction these days. Therefore, the hull form development for the large size ferry should be carefully carried out with some design points such as high service speed, severe criteria for stability, and complex design of appendages. This paper reviewed principal particulars and hull form characteristics of a high-speed large passenger ferry. It is also suggested the optimization method of hull form and appendages in point of resistance & propulsion performance. Finally, it is also introduced a high-speed large passenger ferry developed by Samsung Heavy Industries Co., Ltd., the key design points in hull form development.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.4
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• pp.8-15
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• 2003

This paper presents the method for developing an optimum hull form with minimum wave resistance using SQP(sequential quadratic programming) as an optimization technique. The wave resistance is evaluated by a Rankine source panel method with non-linear free surface conditions and the ITTC 1957 friction line is used to predict the frictional resistance coefficient. The geometry of the hull surface is represented and modified using B-spline surface patches. The optimization method is applied to Series 60 hull and KCS(KRISO 3600 TEU Container Ship). The obtained results prove that the method is appropriate for preliminary hull form design.

• Journal of Ocean Engineering and Technology
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• v.11 no.2
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• pp.131-137
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• 1997

The technology of small and medium sized shipbuilding companies is lower relatively to major shipbuilding companies, and should be up-graded from the viewpoint of national economic development. In spite that hul form design is one of the most important elements with respect to shipbuilding technology, small and medium sized shipbuilding companies are incapable of developing hull form. Inorder to support technically such companies hull form development was carried out for G/T 999ton class tanker and D/W 4990ton class tanker which are the typical vessels operating in coastal area. The operating efficiency for the developed hull forms are impeoved by 30% for G/T 999ton class tanker and 24% for D/W 4990 tonclass tanker respectively. The results of hull form development including ship model test and performance analysis are presented in this paper.

• Journal of Ocean Engineering and Technology
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• v.13 no.4 s.35
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• pp.174-181
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• 1999

A form parameter method compounds the form parameters which define the hull geometric characteristics. This method can transform a hull form by changing the form parameters. The form parameter method is a hull define method without utilization of mother ships. However it is difficult to determine these form parameters. Thus, we are complemented the form parameter method using the neural networks. It is found that the form parameter method using the neural networks is efficient in hull form design by consideration of application examples.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.453-458
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• 2002

This paper deals with the vibration reduction of hull mount system of ship structures brought by ER smart structures. The hull mount is used to isolate the vibration of equipment from the host structures. Utilizing the tunable characteristics of ER fluids, ER inserts are made in the hull mount structure. Different types of ER inserts are proposed and the vibration characteristics are investigated. A hull mount structure is made and the influence of ER inserts are experimentally studied. An extensive modal test is empirically conducted to identify natural frequencies and mode shapes according to the applied electric field and the types of ER insert. The frequency tunable characteristics of ER inserts can be applied to many mounting structures for vibration reduction.