• KDI Journal of Economic Policy
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• v.14 no.4
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• pp.3-26
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• 1992

The pupose of this paper is to construct a price determination model of the Korean economy and to find out the propogation mechanism of monetary and fiscal policies. The model is a small-size macroeconometric model consisted of ten core equations : consumption, investment, exports, imports, consumer price index, wage rate, corporate bond rate, potential GNP, capital stock, and GNP identity. The model is a Keynesian model : consumer price index is determined by markup over costs, and wage rate is expressed by Phillipse curve ralation. Two features of the model, however, distinguish this model from other macroeconometric models of the Korean economy. First of all, the estimation of potential GNP and the capital stock is endogenized as suggested by Haque, Lahiri, and Montiel (1990). This allows us to calculate the level of excess demand, which is defined as the difference between the actual GNP and the potential GNP. Second, interest rate, inflation and wages are all estimated as endogenous variables. Moreover, all quantity variables include price variables as important determinants. For instance, interest rate is an important determinant of consumption and investment. Exports and imports are determined by the real effective exchange rate. These two features make the interactions between excess demand and prices the driving forces of this model. In the model, any shock which affects quantity variable(s) affects excess demand, which in turn affects prices. This strong interaction between prices and quantities makes the model look like a classical model over the long run. That is, increases in money supply, government expenditures, and exchange rate (the price of the U.S. dollar in terms of Korean won) all have expansionery effects on the real GNP in the short run, but prices, wage, and interest rate all increase as a result. Over the long run, higher prices have dampenning effects on output. Therefore the level of real GNP turns out to be not much different from the baseline level ; on the other hand, the rates of inflation, wage and interest rate remain at higher levels.

• Journal of Energy Engineering
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• v.24 no.2
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• pp.9-16
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• 2015

As electricity is an indispensable input to human's existence and industrial production, economic benefits arise from consumption. The economic benefits of the electricity consumption are useful information in various fields of electricity-related policy. Therefore, this study attempts to value the economic benefits from electricity use. The economic benefit of electricity consumed is the area under the demand curve which made of the sum of the actual consumer expenditure and the consumer surplus. Consumer expenditure can be easily observed but the information on price elasticity of demand is necessarily required to compute consumer surplus. This study derives the estimates for price elasticities through literature review. The price elasticities of the electricity demand for residence, industry, and commercial are estimated to be -0.332, -0.351, and -0.263, respectively. Because the consumer surplus of the electricity consumption for residence, industry, and commercial are computed to be 191.54, 143.44, and 231.91 won per kWh, respectively. Given that average prices of electricity use were 127.02, 100.70, and 121.98 won per kWh for the year 2013, the economic benefit are calculated to be 318.56, 244.14, and 353.89 won per kWh, respectively. We can convert the values to 321.96, 246.75, and 357.67 won per kWh in 2014 constant price, respectively, using consumer price index. They can be used in the economic feasibility analysis of a new electricity supply project.

• Journal of Environmental Impact Assessment
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• v.32 no.6
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• pp.488-502
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• 2023

Ecosystem service accounting must measure ecosystem supply functions, demand, and the actual service flows that occur between them. In order to measure flows, supply and demand relationships must be defined, and a methodology that can objectify complex connections is needed. Although various studies on ecosystem services have been conducted in Korea, but researches on accounting for ecosystem services are not enough. The purpose of this study is to evaluate flood control ecosystem services by applying the EU methodology studied in the Experimental Ecosystem Account (EEA) of System of Environmental Economy Account (SEEA) and explore ways to introduce ecosystem account. To conduct the study, the ecosystem's runoff retention potential, social and economic demand for flood control, and actual service benefit flows formed from the relationships between them were modeled and quantified on a spatial basis. As a result of calculating the actual flow of flood control ecosystem services, the total domestic service amount was calculated to be 165,595 (ha), and it was confirmed that much of it was concentrated in agricultural land. In order to account for domestic flood control services in the future, key spatial data such as land cover maps must be continuously established and managed, and researches on input data and methodologies applicable to various spatial scopes such as national, regional, and unit watersheds are expected to be necessary.

• Environmental and Resource Economics Review
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• v.33 no.2
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• pp.113-133
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• 2024

Variable renewable energy (VRE) such as solar and wind power is the main sources of achieving carbon net zero, but it undermines the stability of power supply due to high variability and uncertainty. Energy storage system (ESS) can not only reduce the curtailment of VRE by load shifting but also contribute to stable power system operation by providing ancillary services. This study analyzes how the allocation of ESS resources between load shifting and ancillary service can contribute to maximizing the efficiency of power supply in a situation where the problems caused by VRE are becoming more and more serious. A stochastic power system optimization model that can realistically simulate the variability and uncertainty of VRE was applied. The analysis time point was set to 2023 and 2036, and the optimal resource allocation strategy and benefits of ESS by varying VRE penetration levels were analyzed. The analysis results can be largely summarized into the following three. First, ESS provides excellent functions for both load shifting and ancillary service, and it was confirmed that the higher the reserve price, the more limited the load shifting and focused on providing reserve. Second, the curtailment of VRE can be a effective substitute for the required reserve, and the higher the reserve price level, the higher the curtailment of VRE and the lower the required amount of reserve. Third, if a reasonable reserve offer price reflecting the opportunity cost is applied, ESS can secure economic feasibility in the near future, and the higher the proportion of VRE, the greater the economic feasibility of ESS. This study suggests that cost-effective low-carbon transition in the power system is possible when the price signal is correctly designed so that power supply resources can be efficiently utilized.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.198-201
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• 2009

As a way to improve the safety of automotives and to reduce the weight of vehicles, new forming technologies and advanced materials are in high demand in the automotive industry. However, the advanced strength steel has inferior formability and large springback. In order to overcome such drawbacks, the hot press forming process (HPF) has been being applied for forming of automotive sheet parts. In this work, new equipment was suggested to measure unlimited displacement range compared to previous one which was able to measure only up to 10mm displacement range. The external extensometer connected with grips by wire was applied to equipment so that total strain range was measured up to failure also in high temperature. And the finite element analysis was conducted to characterize the mechanical properties of the HPF steel. Finally, the flow curves were represented by utilizing the Johnson-Cook type equation both in uniform and post-uniform deformation regions.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.8
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• pp.834-839
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• 2012

Recently, mechanical components with miniaturized size, complex shape and fine surface are on demand from industries such as mobile electronics, medical devices and defense. The size of them is smaller than several millimeters, the shape has micro-holes, curve, or multi-step and the surface is mirror-like. This features are not able to be machined with the conventional machining, therefore electro-discharge machining (EDM), cutting, and laser machining have been applied. If the technologies are assisted by vibration, high aspect ratio and good surface are to be achieved. In this paper, prior and current researches of vibration-assisted machining are reviewed. Machining mechanisms with vibration-assisting are explained, their effects are shown, and vibrating apparatuses are discussed. Especially, comparison between with and without vibration assisting is presented. This review shows the vibration-assisted machining is effectively fabricate the components with small and complicated shape and fine surface finish.

• Structural Engineering and Mechanics
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• v.33 no.2
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• pp.239-255
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• 2009

In the companion paper, a simple but effective analysis procedure termed an Improved Modal Pushover Analysis (IMPA) is proposed to estimate the seismic capacities of multi-span continuous bridge structures on the basis of the modal pushover analysis, which considers all the dynamic modes of a structure. In contrast to previous studies, the IMPA maintains the simplicity of the capacity-demand curve method and gives a better estimation of the maximum dynamic response in a bridge structure. Nevertheless, to verify its applicability, additional parametric studies for multi-span continuous bridges with large differences in the length of adjacent piers are required. This paper, accordingly, concentrates on a parametric study to review the efficiency and limitation in the application of IMPA to bridge structures through a correlation study between various analytical models including the equivalent single-degree-of-freedom method (ESDOF) and modal pushover analysis (MPA) that are usually used in the seismic design of bridge structures. Based on the obtained numerical results, this paper offers practical guidance and/or limitations when using IMPA to predict the seismic response of a bridge effectively.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.4
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• pp.69-79
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• 2014

Coastal wetlands are among the most productive biomes in the Earth. The economic values include the direct use of a coastal wetland's ecosystem services, such as food, raw materials, recreation, and tourism. Other values comprise the indirect use of a coastal wetland's ecosystem services, such as carbon sequestration, waste-water treatment, and erosion prevention. In particular, Suncheon Bay is recently attracting attention as the most successful case of the preservation and restoration. This study applies Travel Cost Method (TCM) to estimate the economic value by drawing the demand curve for trips to Suncheon Bay. The TCM is an approach used for economic valuation of non-market goods and services. Based on the results of TCM, this study shows that the economic benefit from recreational uses of the site adds up to \174.7 billion per year. It is also significant in the sense that monetary information is suggested to help local policy makers evaluate the realistic values of coastal wetlands.

• Transactions of Materials Processing
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• v.20 no.3
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• pp.193-205
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• 2011

Because of its rustproof property, stainless steel is widely used in kitchen appliances, building materials, electronics, chemical plants and automobile exhausts. In addition, the utilization of stainless steel for fuel cell application is growing. As the demand for this material increases, it is necessary to study the basic properties of stainless steel such as corrosion resistance, heat transfer, formability, cutting or shearing ability and weldability. In this article, the mechanical properties, formability and press forming performance of stainless steel are reviewed. Since temperature and strain rate affect the press forming performance of STS304(austenitic) stainless steel, the influence of these parameters on the plastic behavior should be investigated. Moreover, measures for the prevention of ridging of STS430(ferritic) and delayed fracture of STS430, which respectively appear during and after press forming, should be considered. Recently, stainless steel sheets with a thickness lower than 0.2 mm have been widely used in applications for mobile phone, digital camera and fuel cell separator. Therefore, there is a growing interest of studying the grain size effect and plasticity at the crystal scale in order to understand the anisotropic behavior and micro forming ability of thin sheets. This review paper was written with the objective of helping engineers and researchers to understand the forming characteristics of stainless steel and to establish standards in plastic forming techniques.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2001.11a
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• pp.37-57
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• 2001

Digital technology enhanced the improvement of technological aspects in the both broadcasting and telecommunications industries. The infrastructures of each industry converged to one, which impacts not only on technology but also on the broadcasting service. The current broadcasting service is characterized by one-way service, but it'll changed to be customized, or two-way service that reflects the interest of customers. This change requires a new standard to categorize and analyze the future broadcasting service converged and market structure, differing from the present standard based on the transmission channels. This study aims at forecasting the demand of interactive TV service as a representative broadcasting service in the near future, and analyzing the market structure of the broadcasting services. We assume that the present broadcasting and information and telecommunications services such as terrestrial, cable TV, satellite, digital TV services and high-speed broadband service have strong relationship with interactive TV service. First we use Bass diffusion method to predict the diffusion curve of the present five services. Then we analyze the relationship between the present services and interactive TV service by Delphi method. Finally we estimate the potential subscription number of interactive TV service based on the relationship among the services and diffusion parameters.