• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.441-444
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• 2007

The inside wall of a coal gasifier is lined with refractory, and the corrosion of the refractory by coal sag is an important parameter affecting the refractory lifetime and the replacement period. This paper examines the changes in microstructure of a chromia refractory due to chemical reactions with penetrating slag as a function of slag composition. The effects of CaO and $Fe_2O_3$ concentrations were studied using Datong and KIDECO slag. Static corrosion experiments were carried out, the percent slag penetration and changes in the microstructure were determined by SEM/EDX analyses. FactSage equilibrium calculations were carried out to determine the equilibrium products and the predictions were compared with experimental observations.

• Journal of Biosystems Engineering
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• v.32 no.6
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• pp.403-407
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• 2007

This study was performed to determine desorption equilibrium moisture contents(EMC) of rapeseed grown in Korea. EMC values were measured by static method using saturated salt solutions at three temperature levels of 30, 40 and $50^{\circ}C$, and eight relative humidity levels in the range from 11.0 to 83.6%. The measured EMC values were fitted to Chung-Pfost, Modified Halsey, Modified Henderson and Modified Oswin models by using nonlinear regression analysis. The results of root mean square errors for four models showed that Halsey and Modified Oswin Models could serve as good models, but the Chung-Pfost and Modified Henderson models could not show reasonably good fitting.

• Management Science and Financial Engineering
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• v.19 no.1
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• pp.11-16
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• 2013

This paper derives an equilibrium asset price when there exist three kinds of traders in financial market: a risk-averse informed trader, noise traders, and risk neutral market makers. This paper is an extended version of Kyle's (1985, Econometrica) continuous time model by introducing insider's risk aversion. We obtain not only the equilibrium asset pricing and market depth parameter but also insider's value function and optimal insider's trading strategy explicitly. The comparative static shows that the market depth (the reciprocal of market pressure) increases with time and volatility of noise traders' trading.

• Journal of Biomedical Engineering Research
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• v.12 no.3
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• pp.149-156
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• 1991

In this paper, fluttering behavior of mechanical bileaflet heart valve prosthesis was analyzed taking into consideration of the impact between valve plate and stopper Vibration system of the valve was modeled as a rotating system, and equations are induced by moment equilibrium equations. Lift force, drag force, gravity and buoyancy were considered as external forces acting on the valve plate/ The 4th order Runge-Kutta method was used to solve the equations. Valve plate does not come to the static equilibrium position at a stretch, but come to that position after under damping vibration. Damping ratio increases as the cardiac optput increases, and the mean damping ratio is in the range of 0.16~40.25. Fluttering frequency does not have any specific value, but varies as a function of time. It is in the range of 10~40Hz. Valve opening appears to be affected by the orientation of the of the valve relative to gravitational forces.

• Transactions of the Korean hydrogen and new energy society
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• v.16 no.4
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• pp.307-314
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• 2005

In this work, a static volumetric method was experimentally implemented to measure the adsorption isotherm of hydrogen and methane by the activated carbon. The equilibrium data of stationary phase and mobile phase were correlated into the Langmuir, Freundlich, Langmuir-Freundlich, and Toth isotherms, respectively. In addition, the comparison between prediction and experimental data was made. By a nonlinear regression analysis, the experimental parameters in the equilibrium isotherms were estimated and compared. Then, the linear and quadratic equations for pressure and temperature to adsorption amounts were expressed. The adsorption amounts were increased with the pressure increase and the temperature decrease.

• Environmental and Resource Economics Review
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• v.5 no.1
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• pp.1-39
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• 1995

본 연구는 에너지정책을 종합적 차원에서 일반경제정책과 병행하여 정량적으로 분석할 수 있는 수리모형 (numerical multi-sector general equilibrium model)을 개발하기 위하여 시도되었다. 모형은 크게 (i) 가격/기술변화 반응적인 투입-산출계수를 내생화한 "산업간 거래모형 (inter-industry production model)", (ii) 민간에 의한 최종부문 수요를 나다내는 "소비자 선택모형 (consumer choices model)", 그리고 (iii) 생산물시장과 본원적 투입요소시장, 수출입시장 등에서 민간기업 정부 및 해외라는 개별 경제주체간의 행태를 반영하는 "거시경제 (성장) 모형 (macro-econometric growth model)"으로 구성되어 있다. 이러한 방법은 분석경제를 충분히 세분하고 제(諸)경제변수들의 동시결정적 과정을 중시한 일반균형적 /부문적 접근방법 (general equilibrium/sectoral approaches)을 취함으로써 지금까지 단순한 거시경제모형(aggregate macroeconomic models)이나 전통적 산업연관모형 (static input-output models)에만 의존해 오던 경제예측이나 경제 및 에너지관련 정책의 효과분석이 한층 더 강화될 수 있을 것으로 기대된다.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.1
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• pp.163-170
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• 2001

In this paper, a massless link model transmitting external forces is developed to achieve the numerical efficiency in simulation of vehicle suspension systems. Forces acting on links are resolved and transmitted to attached points with a quasi-static assumption. Also, a theoretical derivation and computer implementation of a massless link with bushing elements are proposed. In the massless link with bushing elements, one end is connected to the adjacent body with bushings and the other end is connected with a spherical joint. The deformation of a massless link with bushing elements is theoretically determined by minimizing the potential energy function with quasi-static equilibrium assumption at each time step. Several simulations with a full vehicle model are carried out to compare the efficiency of the developed massless link component. From the results, it is concluded that the proposed approach can reduce the computational time considerably.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.4
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• pp.248-256
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• 1996

This paper presents an anti-reset windup (ARW) compensation method for saturating control systems with multiple controllers and/or multiloop configuration. The proposed ARW method is motivated by the concept of equilibrium point. The design parameters of the ARW scheme is derive explicitly by minimizing a reasonable performance index. In the event of saturation, the resulting dynamics of the compensated controller reflects the dynamics of the linear closed-loop system. The proposed method guarantees the total stability o fthe resulting control systems under a certain condition. An illustrative example is given to show the effectiveness of the proposed method. The paper is an extension of the results in Park and Choi[10].

• Journal of Advanced Research in Ocean Engineering
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• v.4 no.1
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• pp.25-34
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• 2018

In this study, the behavior of the coupled mooring system and floating body is analyzed. The related works are introduced for the mooring analysis of the floating body. Equations motion are introduced for calculating mooring force connected with the floating body. For formulating the equations of motion, the concept of the constrained force is applied for compact expression of it. The input and output data of the module for calculating mooring force is defined. The static analysis and quasi-static analysis are performed. For the analysis, equilibrium equation for elastic catenary mooring line is used by employing finite element method, and the C# solver is developed in this research. The analysis results are validated by comparing with other research results.

• Steel and Composite Structures
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• v.19 no.4
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• pp.829-841
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• 2015

In this paper, a refined exponential shear deformation beam theory is developed for bending analysis of functionally graded beams. The theory account for parabolic variation of transverse shear strain through the depth of the beam and satisfies the zero traction boundary conditions on the surfaces of the beam without using shear correction factors. Contrary to the others refined theories elaborated, where the stretching effect is neglected, in the current investigation this so-called "stretching effect" is taken into consideration. The material properties of the functionally graded beam are assumed to vary according to power law distribution of the volume fraction of the constituents. Based on the present shear deformation beam theory, the equilibrium equations are derived from the principle of virtual displacements. Analytical solutions for static are obtained. Numerical examples are presented to verify the accuracy of the present theory.