• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.336-339
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• 2006

With the steady depletion off fossil fuel reserves, hydrogen based energy sources become increasingly attractive. Therefore hydrogen production or separation technologies, such as Bas separation membrane based on adsorption technology, have received enormous attention in the industrial and academic fields. In this study, the transport mechanisms of the MTES (methyltriethoxysilane) templating silica/a-alumina composite membrane were evaluated by using unary, binary and quaternary hydrogen gas mixtures permeation experiments at unsteady- and steady-states. Since the permeation flux in the MTES membrane, through the experimental and theoretical study, was affected by molecular sieving effects as well as surface diffusion properties, the kinetic and equilibrium separation should be considered simultaneously in the membrane according to molecular properties. In order to depict the transient multi-component permeation on the templating silica membrane, the GMS (generalized Maxwell-Stefan) and DGM (dust Bas model) were adapted to unsteady-state material balance

• 소음진동
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• 제8권4호
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• pp.715-722
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• 1998

An investigation into the stochastic bifurcation and response statistics of an autoparameteric system under broad-band random excitation is made. The specific system examined is a spring-pendulum system with internal resonance, which is known to be a good model for a variety of engineering systems, including ship motions with nonlinear coupling between pitching and rolling motions. The Fokker-Planck equations is used to genrage a general first-order differential equation in the dynamic moment of response coordinates. By means of the Gaussian and non-Gaussian closure methods the dynamic moment equations for the random responses of the system are reduced to a system of autonomous ordinanary differential equations. In view of equilibrium solutions of this system and their stability we examine the stochastic bifurcation and response statistics. The analytical results are compared with results obtained by Monte Carlo simulation.

• 한국정밀공학회지
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• 제18권3호
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• pp.175-181
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• 2001

An investigation into the response statistics of a spring-pendulum system whose base oscillates randomly along vertical and horizontal line is made. The spring-pendulum system with internal resonance examined is known to be a good model for a variety of engineering systems, including ship motions with nonlinear coupling between pitching and rolling motions. The Fokker-Planck equation is used to generate a general first-order differential equations for the random responses of the system are reduced to a system of autonomous ordinary differential equations. In view of equilibrium solutions of this system and their stability, the response statistics is examined. It is seen that increase in horizontal excitation level leads to a decreased width of the internal resonance region.

• 자원ㆍ환경경제연구
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• 제10권4호
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• pp.495-513
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• 2001

We investigate a practical method of calculating the impact of multiple domestic energy price change on the final demand, production, the export and import change, the change in the balance of payment of Korean economy. By combining an existing computable general equilibrium (CGE) model with the traditional input-output analysis with two additional assumptions on the price behavior, we provide a cost-effective method of analyzing the impact of multiple energy price changes on the domestic economy. The energy price shock we used in this paper is 0.127% increase weighted by the sectoral productions. The total impacts on price level and GDP are 1.258% and -0.940%, respectively. The impact on the total output (GDP and intermediate goods) is about -1.580%.

• 자원ㆍ환경경제연구
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• 제11권1호
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• pp.145-184
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• 2002

This paper analyzes the impact of imposing carbon tax on the Seoul economy to reduce Greenhouse Gas(GHG) emission. We construct the social accounting matrix of Seoul, specifying energy and transport sectors which is closely related to air pollution. Then, we formulated the computable general equilibrium (CGE) model of seoul and performed scenario analysis. The main result shows that the economic cost of GHG reduction is quite large but the health benefit is also considerable. It also suggests the importance of cost effective measures such as the development of new energy technology and the improvement of energy efficiency.

• 한국공간구조학회논문집
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• 제18권2호
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• pp.25-34
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• 2018

This study investigated a bio-tensegrity structural system that combines the characteristics of a general tensegrity structural system with a biological system. The final research objective is to accomplish a changeability for the structural system as like the movement of the natural bio-system. In the study, we present a shape finding procedure for the two stage bio-tensegrity system model inspired by the movement pattern of animal backbone. The proposed system is allowing a dynamic movement by introducing the concept of "saddle" for the variable bio-tensegrity structure. Several shape finding analysis example and results are presented and shows a efficient validation and suitability.

• 대한전기학회논문지
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• 제37권10호
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• pp.740-747
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• 1988

This paper describes the parameter convergence property for an adaptive identifier and deals with the stability of the adaptive system in terms of the general error model. The Persistent Excitation (PE) condition to guarantee parameter convergence is derived using the Power Spectrum Analysis. In the adaptive identifier designed under the assumptions that the plant has not unmodelled dynamics, it can be shown that the equilibrium points of adjustable parameters are independent on the position or the number of input spectrums, if the adaptive signal is PE. When the plant contains unmodelled dynamics and the same controller is used, the PE condition can still hold but the parameter tuned values are changed with the spectrum.

• 대한기계학회논문집A
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• 제28권2호
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• pp.133-142
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• 2004

In this article, the constitutive relations of three types of piezoelectric benders, which are a unimorph bender, a bimorph bender and a triple-layer bender, are derived based on the beam theory under the quasi-static equilibrium condition. The relation coefficients are described as the geometry and material properties of the benders. More general constitutive relations involving fixed-free, fixed-roll, and fixed-simply supported boundary conditions under the inconsistent length condition between the piezoelectric layer and the nonpiezoelectric one are discussed. The complicated constitutive relations can be easily calculated and checked by using the symbolic function in ‘Mathematica’. The relation coefficients for the benders are plotted in three dimensional graph using the developed program.

• Bulletin of the Korean Chemical Society
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• 제17권2호
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• pp.131-138
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• 1996

The conformational transition of oligopeptide multimer,-(HPPHPPP)n-, is studied (H:hydrophobic amino acid, P:hydrophilic amino acid). The helix/coil transitions are detected in the multimer. The transition depends on the number of amino acid in the sequence, the concentration of the oligopeptide, and temperature which affects helix stability constant (${\xi}$) and hydrophobic interaction parameter (wj). In the thermodynamic equilibrium system jA${\rightarrow}$Aj (where A stands for oligopeptide monomer), Skolnick et al., explained helix/coil transition of dimer by the matrix method using Zimm-Bragg parameters ${\xi}$ and $\sigma$ (helix initiation constant). But the matrix method do not fully explain dangling H-bond effects which are important in oligopeptide systems. In this study we propose a general theory of conformational transitions of oligopeptides in which dimer, trimer, or higher multimer coexists. The partition of trimer is derived by using zipper model which account for dangling H-bond effects. The transitions of multimers which have cross-linked S-S bonds or long chains do not occur, because they keep always helical structures. The transitions due to the concentration of the oligopeptides are steeper than those due to the chain length or temperature.

• 노동경제논집
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• 제42권2호
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• pp.1-35
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• 2019

본 논문은 간단한 일반균형 모형을 통해 소득 이전과 임금 보조금 정책의 경제 효과를 비교한다. 지원 대상인 저임금 근로자가 수요의 소득탄력성이 높은 재화 및 서비스 생산에 집약되어 있을수록 조세를 통한 재분배 효과는 제한적으로 나타난다. 한편, 지원 방식에 있어서 근로장려세제와 같은 임금보조금(wage subsidy) 정책은 단순한 소득 이전(income transfer)에 비해 고용과 GDP 증가라는 긍정적 효과를 동반할 수 있지만, 그 재분배 효과는 노동공급뿐 아니라 노동수요의 탄력성에 크게 의존하는 것으로 나타났다. 결과적으로 효율성과 형평성의 최적 조합을 위해서는, 각 정책의 효과에 대해 면밀한 실증분석이 필요하다고 판단된다.