• Journal of the Korean association of regional geographers
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• v.15 no.2
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• pp.307-315
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• 2009

The purpose of map generalization is a method of map making to transmit the concise cartographic representation and geographic meaning. New generalization algorithm has been developed to be applied in the digital environments by the development of computer cartography. This study aims to look into possibilities of the multiscale mapping by generalization in application with the coordinate transformation and LoD(level of detail) in the web cartography. A method of the coordinate transformation is to improve a transmission of spatial data. Lod is a method which is making web map with selection spatial data by zoom level of users. Layers for test constructed contour line, stream network, the name of a place, a summit of mountain, and administrative office. The generalization was applied to zoom levels by scale for the linear and polygonal features using XML-Based scalable vector graphics(SVG). Resultantly, storage capacity of data was minimized 41% from 9.76mb to 4.08mb in SVG. Generalization of LoD was applied to map elements by stages of the zoom level. In the first stages of zoom level, the main name of places and administrative office, higher order of stream channels, main summit of mountain was represented, and become increase numbers of map elements in the higher levels. Results of this study can help to improve esthetic map and data minimization in web cartography, and also need to make an efforts to research an algorithm on the map generalization over the web.

• Journal of KSNVE
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• v.9 no.3
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• pp.525-534
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• 1999

The present paper proposes a generalized modal analysis procedure for non-uniform, distributed-parameter rotor-bearing systems. An exact element matrix is derived for a Timoshenko shaft model which contains rotary inertia, shear deformation, gyroscopic effect and internal damping. Complex coordinates system is adopted for the convenience in formulation. A generalized orthogonality condition is provided to make the modal decomposition possible. The generalized modal analysis by using a modal decomposition delivers exact and closed form solutions both for frequency and time responses. Two numerical examples are presented for illustrating the proposed method. The numerical study proves that the proposed method is very efficient and useful for the analysis of distributed-parameter rotor-bearing systems.

• Transactions of the Korean Society of Mechanical Engineers
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• v.6 no.2
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• pp.176-182
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• 1982

이 논문에서는 평판의 배선형 해석에 대한 Berger의 방정식을 쉘좌표가 직교곡선좌표계로 표시 되는 Shallow 쉘에 대하여 일반화하여 운동방정식을 유도하였다. 해석의 예로서, 이 방정식을 사용하여 고정된 경계를 가진 원판과 Shallow 구쉘에 대한 배선형 진동문제를 해석하였으며, 정력학의 문제로서 원판이 동심원내에 균일하중을 받을때와 중심에 집중하중을 받을 때의 large deflection에 대하여 고찰하였고 나중문제에 대한 수치해를 구하였다.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.6
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• pp.348-357
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• 2021

In this paper, the generalized hydrodynamic force and response of a flexible body are calculated at different reference coordinate systems. We generalize the equation of motion for a flexible body by using the conservation of momentum (Mei et al., 2005). To obtain the equations in the generalized mode, two different reference coordinates are adopted. The first is the body-fixed coordinate system by a rigid body motion. The other is the inertial coordinate system which has been adopted for the analysis. Using the perturbation scheme in the weakly-nonlinear assumption, the equations of motion are expanded up to second-order quantities and several second-order forces are obtained. Numerical tests are conducted for the flexible barge model in head waves and the vertical bending is only considered in the hydroelastic responses. The results show that the linear response does not have the difference between the two formulations. On the other hand, second-order quantities have different values for which the rigid body motion is relatively large. However, the total summation of second-order quantities has not shown a large difference at each reference coordinate system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.838-843
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• 2001

Internal damping plays an important role in some rotor dynamic systems with the use of various materials for shafts, for example, composite material. However, although the effects of internal damping have been investigated for a couple of decades, there are several different internal damping models in use, none of which are accepted as the most reliable model. The purpose of this paper is to compare the results of dynamic analysis of rotor systems with several different internal damping models. The exact dynamic element method is used to formulate and analyze the problem. The simulation results provided in this paper may be useful for the dynamic analysis of high rotor systems subject to significant internal damping.

• Tribology and Lubricants
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• v.26 no.5
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• pp.283-290
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• 2010

In this study, the stiffness and damping coefficients of herringbone grooved air journal bearings are studied. A generalized coordinate transformation method to handle the complex geometry of incompressible fluid bearing is modified for compressible fluid. The modified equations are discretized by the base of finite difference method. A new computer program using Visual C++ language is developed. The load carrying capacity and stiffness and damping coefficients are calculated according to the design parameters like groove depth or the number of grooves and compared to that of plain air journal bearings.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.10
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• pp.813-820
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• 2003

Conventional modal analysis techniques are known to be inappropriate for asymmetrical rotor systems, when the equations of motion are written in the stationary coordinates, due to the presence of time varying parameters. This paper presents a generalized modal analysis method for asymmetrical rotor systems in the stationary coordinates, employing the modulated coordinates and the lambda matrix formulation. A numerical example with a flexible asymmetric rotor model is provided to demonstrate the effectiveness of the proposed modal analysis method. As an application of the proposed method, modal analysis is also performed with an open cracked rotor system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.526-531
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• 2003

Conventional modal analysis techniques are known to be inappropriate for asymmetrical rotor systems. when the equations of motion are written in the stationary coordinates, due to the presence of time varying parameters. This paper presents a generalized modal analysis method for asymmetrical rotor systems in the stationary coordinates, employing the modulated coordinates and the lambda matrix formulation. A numerical example with a flexible asymmetric rotor model is provided to demonstrate the effectiveness of the proposed modal analysis method. As an application of the proposed method, modal analysis is also performed with an open cracked rotor system.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1995.11a
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• pp.50-55
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• 1995

향상되어진 93-PCGC-2는 기존의 PCGC-2와 같이 미분탄 연소를 포함하는 다양한 반응성흐름과 비반응성 흐름을 설명하기 위해 2차원 정상상태 모델로 제시되어 졌다. 93-PCGC-2는 실린더형의 축 대칭계에 응용되어질 수 있고, 난류(Turbulence)는 유체역학식과 연소기구 양쪽을 위해 고려되어졌으며, 불연속 세로좌표 방법(Discrete Ordinates Method)을 이용하여 기체, 벽 및 입자들로부터의 복사열(Radiation)을 모사하였다. 입자상은 입자 무리들의 평균 경로들을 따라 해석하는 Lagrangian계의 해석법으로 모델화되어졌다. 석탄의 팽윤(Swelling)과 촤의 반응성에 관한 부모델과 더불어 새롭게 일반화된 석탄 탈휘발화 부모델 (FG-DVC)도 첨가되어졌다. 비균일 반응기구는 확산과 화학반응 둘 모두를 고려하였다. 주요 기상반응은 국부 순간 평형을 가정하여 모델화하였다. 그래서 반응속도는 혼합의 난류속도에 의해 제한되어진다. Thermal NOx과 Fuel NOx의 유한속도 화학론(Finite Rate Chemstry)에 대한 부모델은 화학반응속도론와 난류성의 통계치를 통합하여 만들어져 있다. 기상은 반복적인 line-by-line기교에 의해 풀려지는 elliptic partial differential equation으로 묘사되어진다. 수치적인 안정을 고려하기 위해 under-relaxation이 이용되어졌다. 이렇게 코드화된 93-PCGC-2는 연소를 위해 모사되어졌다. 또한 더 나아가 이 수치모델의 활용범위는 미분탄의 가스화에도 활용되어질 것으로 기대되어진다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.1
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• pp.1-15
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• 2000

To reconstruct 3- D shape, It is a common strategy to acquire multiple range Images from different viewpoints and integrate them into a common coordinates In this paper, we particularly focus on the registration and integration processes for combining all range Images into one surface model. For the registration, we propose the 2-step registration algorithm, which consists of 2 steps the rough registration step using all data points and the fine registration step using the high-curved data points For the integration, we propose a new algorithm, referred to as ‘multi-registration’ technique, to alleviate the error accumulation problem, which occurs during applying the pair-wise registration to each range image sequentially, in order to transform them into a common reference frame Intensive experiments are performed on the various real range data In experiments, all range images were registered within 1 minutes on Pentium 150MHz PC The results show that the proposed algorithms registrate and integrate multiple range Images within a tolerable error bound in a reasonable computation time, and the total error between all range Images are equalized with our proposed algorithms.