• Proceedings of the Korean Society of Marine Engineers Conference
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• 2012.06a
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• pp.280-280
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• 2012

DME(Dimethyl Ether) is the one of the massive energy sources synthesized from natural gas. KOGAS has already developed the commercial-scale production plant of DME and has been doing to obtain overseas resources to meet the domestic needs. This paper presents an experimental study on the evaporation phenomena of DME in FPSO or cargo vessel. The various moving motions, along with heat intake cause the evaporation of low temperature liquids in vessel's storage tank. The experimental result shows that the evaporation rate was changed with rolling degree and cycle and liquid level. The rolling motion leads to evaporate about 30~35% of total evaporation quantity and the rest amount from heat intake.

• Bulletin of the Society of Naval Architects of Korea
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• v.8 no.1
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• pp.41-52
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• 1971

In this paper, the authors describe not only the linear-theoretical considerations of the hull forms which many schalors have been investigating by the hydrodynamics as to the rolling ships in the waves, but also measure the rolling angles of the models, the coefficients of the effective wave slopes, the forced rolling moments by the waves, the extinctive curves, and the amplitudes of the waves in view of changing both the drafts and the metacentres so that they may study the inclinations of models in the grinoll motion. Owing to the conclusions of these studies, we can learn the fact that the experimental results of the models in the waves agree almost to the linear-theoretical subjects.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.163-171
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• 1999

The major source of railway noises is rolling noise caused by the interaction of the wheels and rails. This rolling noise is generated by the roughness of the wheel/rail surface on tangent tack in the absence of discontinuities, such as wheel flats or rail joints. These roughness cause relative vibrations of the wheel and rail at their contact area. The vibrations generated at the contact area are transmitted through the wheel and rail structures, exciting resonances of the wheel and travelling waves ill tile rail. Then these vibrations radiate noise to the wayside. In this paper, we predict the rolling noise radiated from radial/axial motion of the wheel and vertical/lateral motion of the rail using Remington's analytical model and then compare of the predicted sound pressure and measured one. Although there are some inaccuracy in our predication these results show in good agreement between 500 ㎐ and 3150㎐.

• Journal of Institute of Convergence Technology
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• v.12 no.1
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• pp.31-35
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• 2022

This study has been carried out in order to improve the rolling problem by enhancing steering stability compared to the 2021 Student Car of the KNUT_EV team for KSAE. Among the various factors affecting steering performances, it was focused on the height of the centroid of weight, the motion ratio, and the spring deflection. In the 2022 Car, a pull rod suspension was used to reduce the height of the centroid of weight and designed with a structure of the rod and rocker to satisfy the target motion ratio. The spring deflection was testified by ADAMS and ABAQUS analysis, and the spring stiffness was selected at 350lb/inch and 450lb/inch for the front and rear wheels, respectively. As a result, the rolling angle of the 2022 Car was reduced compared to the 2021 Car, and the rolling phenomenon was improved.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1996.10a
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• pp.163-167
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• 1996

The life of rolling elements depends on various factors such as operating conditions and material properties. In this work, the effect of microstructure on the rolling behavior is investigated. Specially, the deformations in the substrate regions before and after rolling are compared. It is found that rolling action causes severe flow of material in the direction opposite to the rolling direction in the case of dry rolling direction. With lubrication, the deformation is more severe at the subsurface region rather than at the surface.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.426-427
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• 2010

최근 휴대기기들의 CMOS 영상 센서의 사용으로 Rolling shutter에 의한 왜곡현상이 발생하고 있다. 이러한 왜곡현상을 보정하기 위한 기존의 방법은 동영상에서의 움직임 정보만을 주로 이용하고 있다. 따라서 본 논문은 움직임 정보를 이용한 보정의 성능을 더욱 좋게 하기위하여 정지영상에서 Rolling Shutter 왜곡현상에 대한 추가적인 움직임 정보를 찾아내고 보정하는 알고리즘을 제안하고 있다.

• International Journal of Ocean System Engineering
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• v.3 no.1
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• pp.10-15
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• 2013

A ship cruising in the ocean oscillates continuously due to wave action. In order to reduce the ship's roll, we developed a fin stabilizer as an anti-rolling device for a 500-ton-class high-speed marine vessel. During the development phase, it was necessary to set up control gains for the motion and hydraulic systems and assess the effectiveness of the anti-rolling performance on the ground. For this reason, a Target Simulator, which simulated the ship's motion, was given operator inputs such as the engine telegraph and waterjet deflection angle, and generated roll using a one-degree-of-freedom motion base. Hardware-In-the-Loop Simulation (HILS) was performed using the Target Simulator in order to confirm the various logics of the developed fin stabilizer, select initial control gains, and estimate the anti-rolling performance. In conclusion, it was confirmed that HILS was very helpful to develop the fin stabilizer because it could reduce the number of sea trial tests that were needed and could find many malfunctions in the factory a priori.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.4
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• pp.41-46
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• 2013

This paper deals with an experimental technique for the measurement of dynamic stability derivatives in the roll motion of aircraft. Experimental aquisition method for aircraft's dynamic stability derivatives is conducted on the oscillation condition of aircraft model in the subsonic wind tunnel. The oscillation of aircraft model was forced by the oscillation apparatus. The forced oscillation technique is the method getting data from the internal balance inserted into the aircraft model during oscillating it. Dynamic stability derivatives of rolling motion were calculated by data reduction from the measurements of rolling moment, frequency and amplitude of aircraft model due to forced oscillation under wind conditions. Results of experiment is obtained similar one with those of roll dynamic stability derivatives measured in other institutes.

• Journal of the Korean Society for Precision Engineering
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• v.6 no.3
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• pp.68-77
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• 1989

The surface rolling for cylindrical surface of a grey cast iron was carried out using a lathe with a simple newly-designed tool system. A surface rolling tool used was steel ball whose diameter was 3/8 inch (9.525mm) The effects of rolling feeds and number of rolling on surface rolling were investigated. The contact pressure between ball and workpiece which was considered as Hertz's contact problem was examined and the track of motion of a ball on the cylindrical surface of a work- piece was measured according to the rolling feed. The results obtained were as follows; 1. The roughness of the machined surface which was originally 5.3 .approx. 28 umRz decreased to 1.2 .approx. 5 umRz according to rolling feeds and numbers of rolling. 2. The hardness increased from Hv 260 to Hv 290 .approx. 310 through 2 .approx. 4 rollings according to the roughness of machined surfaces. 3. The reduction of diameter was found to be proportional to the variations of roughness of previous machined surfaces. About 60% to 90% of reduction in diameter was made during the first rolling process. 4. An equation relating the reduction of diameter and the variation of surface roughness after surface rolling was presented using a geometric surface model. 5. An equation for the calculation of dynamic contact area between pressure ball and workpiece according to the rolling feed was presented.

• Journal of Industrial Technology
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• v.20 no.B
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• pp.95-103
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• 2000

A model trains must have similitude with its original model not only in shape but also in motion. Motion characteristics of a model train under considerations are maximum velocity in straight and circular tracks and stopping distance. Equations of motions are derived to obtain maximum speed and stopping distance based on the Newton's Second Law and the energy principal. To accurately predict traction and resistance force between wheel and rail. wheel slip, or creepage, is taken into consideration. To verify the equations of motion, various experiments have been carried out including measurement of gear efficiency, location of mass center, rolling resistance force, traction force, slip, maximum velocity and stopping distance. This paper addresses how the experiments are setup and carried out in detail. Also the results of experiments are compared with the analytical prediction, which showed good agreements with each other.