• 대한교통학회지
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• 제31권3호
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• pp.74-85
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• 2013

본 연구는 혼잡통행료 징수와 보조금 지급의 후생개선 효과를 일반균형조건을 충족하는 공간모형에서 비교하고 이들이 발생시키는 후생개선 효과를 분해한 후 후생개선 효과의 원인을 규명하고 있다. 본 연구는 Anas and Kim (1996)를 기원으로 구축된 확률균형모형에 수단선택 조건을 추가한 후, Yu and Rhee (2011)와 Rhee (2012)가 제안하는 연구방법론을 응용하여 후생개선 효과를 간접효과와 직접효과 중 입지요인과 수단요인으로 구분하여 관찰한다. 최선의 정책수단(First-best pricing)에 대한 혼잡통행료 부과 또는 보조금 지급의 상대적 효율성은 혼잡통행료 부과의 경우가 보조금 지급에 비하여 높은 것으로 나타났다. 우리는 후생개선 효과의 분해를 통해 이들 효과의 대부분은 수단요인에 의해 달성된 것임을 확인하였다. 대중교통 보조금의 지급은 혼잡통행료 부과에 비하여 장거리 대중교통 분담률을 더욱 증가시키고, 이러한 현상은 혼잡통행료 징수에 비하여 입지요인으로 인한 더욱 많은 후생감소 효과를 유발하여 후생개선 효과는 상대적으로 낮게 나타난다. 이에 대한 원인은 혼잡통행료 부과에 비하여 보조금 지급이 도심 내 과다한 통과교통을 유발했기 때문이다.

• Journal of Korea Trade
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• 제24권8호
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• pp.153-170
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• 2020

Purpose - As the US-China trade war intensifies and lasts long time, there is growing concern about its potential effects on the global economy. In particular, for the countries like Korea that have a large economic dependence on the economy of the two countries, the US-China trade war may have a great repercussion in many ways. The aim of this paper is to investigate the global productivity and market structure implications of the US-China trade war for Korea, as well as for other surrounding countries and regions. Design/methodology - In this paper, we develop a full multi-country/region multi-sector computable general equilibrium (CGE) model of global trade incorporating heterogeneous workers and firms in individual skill levels and used technologies. We then calibrate the model using a global Social Accounting Matrix (SAM) dataset extracted from the recently released GTAP 10 Database, and assess the potential effects of the US-China trade war on the aggregate real productivity and the market structure for Korea, as well as for other surrounding countries and regions. Findings - We show that the US-China trade war may largely affect the aggregate productivity in each sector in each country/region, as well as the global market structure through entry and exit of firms, which results finally in considerable changes in the industrial comparative advantage of each country/region. Though the effects are diverse sector by sector, the results show that Korea may also be affected significantly: concerning the real productivity implications, it is shown that the machinery industry may be affected the most negatively; on the other hand, it is shown that the number of exporting firms may decrease the most in the other transports industry. Originality/value - As the US-China trade war intensifies, many studies have tried to estimate the possible implications, and for this usually the CGE models have largely been used as the standard tool for evaluating the impacts of changes in trade policies. Standard CGE models, however, cannot be used to assess the global productivity and market structure implications due to the symmetric and simplified base assumptions. This paper is the first to analyze and quantify the possible impacts of the US-China trade war on the aggregate productivity and global market structure using a CGE model incorporating endogenous skill-technology assignment of heterogeneous workers and firms.

• 대한기계학회논문집A
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• 제20권9호
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• pp.2854-2865
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• 1996

The concept of variable-geometry truss structure(VGTS) is introduced as a class of actively controlled adaptive structure. VGTS can purposefully vary its geometric configurations by changing the lengths of some members of the structure. General kinematics and inverse kinematics of a statically determinate VGTS(variable geometry truss structure) are studied. The solution technique is based on the Jacobian matrix obtained via joint equilibrium equations. Pseudoinverse control method is applied to resolve the redundancy of a large VGTS. two types of actuator layout of octahedral type VGTS, VG truss and Stewart platform, are compared. Introducing the concept of performance index, Stewart platform based layout was found to has less consumption energy and manipulation time. A functional VGTS model with 3 octahedral modules is designed and manufactured for the labaratory demonstration. Six vertically located length-variable members are used to create general 6 d.o.f. motions.

• Structural Engineering and Mechanics
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• 제45권3호
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• pp.355-371
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• 2013

Single- and multi-span orthotropic functionally graded hollow cylinders subjected to axisymmetrical bending are investigated on the basis of a unified shear deformable shell theory, in which the transverse displacement is expressed by means of a general shape function. To approach the through-thickness inhomogeneity of the hollow cylinder, a laminated model is employed. The shape function therefore shall be determined for each fictitious layer. To improve the computational efficiency, we resort to a transfer matrix method. Based on the principle of minimum potential energy, equilibrium equations are established, which are then solved analytically using the transfer matrix method for arbitrary boundary conditions. Numerical comparisons among a third-order shear deformable shell theory, an exact elastic theory and the present theory are provided for a simply supported hollow cylinder, from which the present theory turns out to be superior in stress estimation. Distributions of displacements and stresses in single- and three-span hollow cylinders with different boundary conditions are also illustrated in numerical examples.

• 한국정보시스템학회지:정보시스템연구
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• 제16권1호
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• pp.47-64
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• 2007

The telecommunication service industry plays a major role in the realization of the perfect information society in the 21st century and, has a great influence in society and culture. Using the Calculable General Equilibrium Model, we analyze the telecommunication service's economic effects on other industries as well as on the national economy. In 2001, the 8 percent increase in the telecom sales caused the 5 billion dollar increase in the GDP, which seems to continue to bring about no less than 5 billion dollar GDP increase each year until 2030. The telecom sales increase has been evaluated to have disproportionately positive effect on transmission device and audio equipment industries. In summary, the telecom sales have a positive net enぉ on the GDP and on most of the industries with a few exceptions.

• Advanced Composite Materials
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• 제18권1호
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• pp.21-42
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• 2009

The vibration characteristics of post-buckled laminated composite doubly curved shells are investigated. The finite element method is used for the analysis of post-buckling and free vibration of post-buckled laminated shells. The geometric non-linear finite element model includes the general non-linear terms in the strain-displacement relationships. The shell geometry used in the present formulation is derived using an orthogonal curvilinear coordinate system. Based on the principle of virtual work the non-linear finite element equations are derived. Arc-length method is implemented to capture the load-displacement equilibrium curve. The vibration characteristics of post-buckled shell are performed using tangent stiffness obtained from the converged deflection. The code is first validated and then employed to generate numerical results. Parametric studies are performed to analyze the snapping and vibration characteristics. The relationship between loads and fundamental frequencies and between loads and the corresponding displacements are determined for various parameters such as thickness ratio and shallowness.

• 한국안전학회지
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• 제18권1호
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• pp.14-18
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• 2003

The structural development of air-water bubble plumes has been measured under different condition on air flow rate in a cylindrical bath. The time-averaged structure of plumes has been measured with an oscilloscope and an electro-conductivity probe. The temperature of bubbles was also obtained by a thermal-infrared camera. Gas volume fraction and bubble frequency were high since bubbles concentrated on the nozzle. In general, their axial and radial values tended to decrease with increasing distance. Bubble temperature reached water temperature within a short time. The present study showed that thermal equilibrium between bubbles and water was completed before bubbles flow became stable.

• East Asian Economic Review
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• 제17권1호
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• pp.3-25
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• 2013

This paper evaluates whether the proposed FTAAP is a desirable policy option for APEC member economies and the world economy. More specifically, this paper qualitatively investigates whether the FTAAP satisfies conditions for a trade bloc to generate positive and sufficient net trade creation effect. In addition, this paper estimates the likely impact of the FTAAP by using a CGE model analysis. From the qualitative analysis based on statistical data, this paper strongly argues that the FTAAP can be a desirable regional trade bloc able to generate positive gains from freer trade. From the ex-ante scenario analysis using both static and capital accumulation CGE Models, this paper concludes that the FTAAP has great potential for improving welfare of participating APEC economies and will boost economic growth in the region. In particular, the FTAAP would be even better if it can be linked with liberalization of trade in services and enhanced trade facilitation.

• East Asian Economic Review
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• 제21권2호
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• pp.167-197
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• 2017

I build a small open economy (SOE) dynamic stochastic general equilibrium (DSGE) model to investigate the effect of a heterogeneous wage contract between regular and temporary workers on a macroeconomic volatility in a financially fragile economy. The imperfect financial market condition is captured by a quadratic financial adjustment cost for borrowing foreign assets, and the labor market friction is captured by a Nash bargaining process which is only available to the regular workers when they negotiate their wages with the firms while the temporary workers are given their wage which simply equals the marginal cost. As a result of impulse responsesto a domestic productivity shock, the higher elasticity of substitution between two types of workers and the lower weight on the regular workers in the firm's production process induce the higher volatilities in most variables. This is reasoned that the higher substitutability creates more volatile wage determination process while the lower share of the regular workers weakens their Nash bargaining power in the contract process.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.399-406
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• 1998

An investigation into the stochastic bifurcation and response statistits 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 generate 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 ordinary 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.