• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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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.

• Journal of KSNVE
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• v.8 no.4
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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.

• KDI Journal of Economic Policy
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• v.30 no.2
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• pp.185-223
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• 2008

This paper considers a heterogeneous agent dynamic general equilibrium model and analyzes effects of an increase in labor income tax rate on labor market and the aggregate variables in Korea. The fiscal policy regarding how the government uses the additional tax revenue may take the two forms: 1) general transfer and 2) earned income tax credit (EITC). The model features are as follows: 1) Workers are heterogeneous in their productivity. 2)Labor is indivisible, hence the analysis focuses on the variation in labor supply through the extensive margin in response to a change in fiscal policy. 3) The incomplete markets are introduced, so individual workers can not perfectly insure themselves against risks related to stochastic changes in income or employment status. 4) The model is of general equilibrium, hence it is equiped to analyze the feedback effect of changes in aggregate variables on individual workers' decisions. In the case of general transfer policy, the government equally distributes the additional tax revenue to all workers regardless of their employment states. Under this policy, an increase in the labor income tax rate dampens work incentives of individual workers so that the aggregate employment rate decreases by 1% compared with the benchmark economy. In the case of EITC policy, only employed workers whose labor incomes are below a certain EITC ceiling are eligible for the EITC benefits. Unlike the general transfer policy, the EITC induces low-income workers to participate the labor market to be eligible for EITC benefits. Hence, the aggregate employment rate may increase by 2.7% at the maximum. As the EITC ceiling increases, too many workers can collect the EITC but the benefits per worker becomes too little so that the increase in employment rate is negligible. By and large, this study demonstrates that EITC may effectively raise the aggregate employment rate, and that it can be a useful policy tool in response to the decrease in the labor force due to population aging as observed in Korea recently.

• East Asian Economic Review
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• v.21 no.2
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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.

• Journal of Integrative Natural Science
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• v.1 no.2
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• pp.127-132
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• 2008

This project follows the heterogeneous agent market segmented model of Landon-Lane and Occhino (2007) with using Korean data, M1 and GDP deflator from 1882:I to 2007:II. This paper estimates parameters with Monte Carlo Markov Chain. The fraction of traders, ${\lambda}$, in Korea is 15.64%. The quarterly preferences discount factor's, ${\beta}$, posterior mean is 0.9922. The posterior mean of the inverse of the elasticity of the labor supply to the real wage, ${\varphi}$, is 0.0316. The elasticity of the labor supply to the real wage has a very large value. By Hansen (1985) and Christiano and Eichenbaum (1992) and Cooley and Hansen (1989), models having large elasticity of the aggregate labor supply better match macroeconomic data.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.1
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• pp.153-166
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• 2022

The study estimates the Structured VAR and the Dynamic Stochastic General Equilibrium Model for the Vietnamese economy based on the new Keynesian model for small and open economies, with the output gap, inflation, policy interest rate, the Vietnamese exchange rate, and the inflation and interest rate in the United States. The paper aims to clarify the impulse response of the macro variables through their shocks. It offers to model the SVAR and DSGE processes, as well as describe why and how interest rate policy is important in the impulse response of macro variables like the output gap and inflation process. The study supports the central role of monetary policy by giving empirical evidence for the new Keynesian theory, according to which an interest rate shock causes the output gap to widen and inflation to decrease. Finally, the application of the DSGE model is becoming more and more popular in the State Bank of Viet Nam to improve its policy planning, analyzing, and forecasting policy towards sustainable and stable growth.

• KDI Journal of Economic Policy
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• v.34 no.4
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• pp.69-90
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• 2012

This paper explores the effect of the countercyclical capital buffer using a DSGE (Dynamic Stochastic General Equilibrium) model with a banking sector. The main results are following. First, if the CAR (capital asset ratio) rises by 1%p as the countercyclical capital buffer, output and credit would increase less than otherwise by 0.8%p and 1.2%p, respectively. Second, the countercyclical capital buffer would decrease both credit and debt of banks, or deposit, and, as a result, boost the CAR. However, if we are going to use monetary policy to control credit expansion by allowing the interest rate to respond to credit, bank capital would also diminish, which would cause the CAR to be lower.

• KDI Journal of Economic Policy
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• v.27 no.1
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• pp.157-183
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• 2005

Using a multi-sector dynamic stochastic general equilibrium model, we investigate the dynamic effects of a variety of shocks to a small open economy. In particular, we calibrate the model to match the main characteristics of business cycles in Korea and analyze the effects of external shocks: the terms of trade and world real interest rate shocks. Business cycles in Korea more closely follow those of the G7 countries rather than Asian countries. The simulation results suggest that an improvement in the terms of trade has positive impact on investment, output and consumption, while a decrease in the world interest rate has a significant and positive effect on investment. This paper concludes that external shocks significantly influence business cycle fluctuations in Korea.

• Environmental and Resource Economics Review
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• v.19 no.2
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• pp.215-242
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• 2010

This study constructs a bayesian neoclassical DSGE model that applies oil usage. The model includes technology shocks, oil price shocks, and shocks to energy policies as exogenous driving forces. First, this study aims to analyze the roles of these exogenous shocks in the Korean business cycle. Second, this study examines the effects of long-term changes in the energy consumption structure, including the reduction in oil use as a share of energy consumption and improvement in oil efficiency. In the case of oil price shocks, results show that these shocks exert recessionary pressure on the economy in line with those obtained in the previous literature. On the other hand, shocks to energy policies, which reduce oil consumption per capital, result in opposite consequences to oil price shocks, decreasing oil consumption. Also, counterfactual exercises show that long-term changes in the energy consumption structure would mitigate the contractionary effects of oil price shocks.