• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.295-297
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• 2013

Reinforcing bar coupling method has a variety of ways including lap-splice method. However, there are problems that need to be improved in terms of constructability, economics analysis. We should be improved about the problems of the existing methods. Accordingly, this study were developed a new type of staggered grip type reinforcing bar coupling. The proposed method show the following effects than existing methods. First, this method can be reduce time through improved workability. Second, increasing safety through the slip removal. Third, improving economic efficiency by reduce the manufacturing costs.

• Journal of Agricultural Extension & Community Development
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• v.28 no.3
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• pp.153-165
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• 2021

This study aims to analyze the difference in production elasticity based on the types of agricultural labor input regarding its qualitative difference in Jeju mandarin production. To estimate the production function of qualityadjusted labor, we have set up a Quality-Adjusted Index based on the market wage of the agricultural field. We have conducted a multiple regression analysis of the newly estimated labor inputs using the Ordinary Least Squares regression. Results show that the production efficiency of aggregate total labor hours (quality-unadjusted labor input) is overestimated compared to quality-adjusted labor with qualitative labor homogeneity. Moreover, by analyzing household labor and employment labor, we have observed that the marginal productivity of household labor exceeds that of employment labor. In conclusion, this study verifies that securing labor input homogeneity is crucial for analyzing agricultural labor hours' economic efficiency accurately.

• Economic and Environmental Geology
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• v.37 no.1
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• pp.133-142
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• 2004

The purpose of this study is to evaluate a laboratory test on arsenic removal effciency for ARD(Acid Rock Drain-age) using limestone and apatite, and on heavy metals removal efficiencies for AMD(Acid Mine Drainage) using apatite and fish bone. As a result of the laboratory test, pH, arsenic removal rate of limestone & apatite are inversely proportional to flow rates and apatite removes 100% of arsenic while limestone removes 37% of arsenic at 0.6$m{ell}$/min/kg flow rate in case of ARD treatment. And the dissolution amount of apatite is twenty five times higher than that of limestone. In case of AMD treatment, fish bone shows higher dissolution rate than apatite, and pH of outlet water reacted with fish bone is higher than that reacted with apatite. The heavy metal removal rates of fish bone are also higher than that of apatite except arsenic removal rate. The precipitate resulted from fish bone reaction with AMD seems to be biological sludge type while that resulted from apatite with AMD is inorganic solid which can settle easily compared with the biological sludge and can be cemented by gypsum. As the results, apatite can be used as a precipitant for the polluted mine waters showing wide range of pH and fish bone can be used for highly contaminated AMD.

• Journal of Korea Water Resources Association
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• v.39 no.5 s.166
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• pp.431-440
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• 2006

Recently, water conflicts are rapidly increasing and more serious. So, it needs to establish the reasonable water allocation rules and criteria. This study aims at performing inter-sectoral water allocation with a focus on economic effciency and social utility. To allocate water among the sectoral water uses, water shortage damage functions were estimated and then converged to the utility functions. Finally, each sectoral water uses are allocated by applying 'law equimarginal utility' to maximize social utility. Also weighting factor which reflects scale and characteristic of water demand in a region was estimated to perform the inter-regional water allocation. The water allocation rule was applied to the future water-deficit situation in Han-river basin. As a result, domestic water use was allocated more sufficient agricultural and industrial water use. Also, the water shortage occurs severely in the rural area like Gangwon-do because of its low urbanization and industrialization. This study suggests a alternative view of the economic water allocation which have difficulty under water supply mechanism in Korea.

• KDI Journal of Economic Policy
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• v.12 no.2
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• pp.51-79
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• 1990

Research on technical efficiency, an important dimension of market performance, had received little attention until recently by most industrial organization empiricists, the reason being that traditional microeconomic theory simply assumed away any form of inefficiency in production. Recently, however, an increasing number of research efforts have been conducted to answer questions such as: To what extent do technical ineffciencies exist in the production activities of firms and plants? What are the factors accounting for the level of inefficiency found and those explaining the interindustry difference in technical inefficiency? Are there any significant international differences in the levels of technical efficiency and, if so, how can we reconcile these results with the observed pattern of international trade, etc? As the first in a series of studies on the technical efficiency of Korea's manufacturing industries, this paper attempts to answer some of these questions. Since the estimation of technical efficiency requires the use of plant-level data for each of the five-digit KSIC industries available from the Census of Manufactures, one may consture the findings of this paper as empirical evidence of technical efficiency in Korea's manufacturing industries at the most disaggregated level. We start by clarifying the relationship among the various concepts of efficiency-allocative effciency, factor-price efficiency, technical efficiency, Leibenstein's X-efficiency, and scale efficiency. It then becomes clear that unless certain ceteris paribus assumptions are satisfied, our estimates of technical inefficiency are in fact related to factor price inefficiency as well. The empirical model employed is, what is called, a stochastic frontier production function which divides the stochastic term into two different components-one with a symmetric distribution for pure white noise and the other for technical inefficiency with an asymmetric distribution. A translog production function is assumed for the functional relationship between inputs and output, and was estimated by the corrected ordinary least squares method. The second and third sample moments of the regression residuals are then used to yield estimates of four different types of measures for technical (in) efficiency. The entire range of manufacturing industries can be divided into two groups, depending on whether or not the distribution of estimated regression residuals allows a successful estimation of technical efficiency. The regression equation employing value added as the dependent variable gives a greater number of "successful" industries than the one using gross output. The correlation among estimates of the different measures of efficiency appears to be high, while the estimates of efficiency based on different regression equations seem almost uncorrelated. Thus, in the subsequent analysis of the determinants of interindustry variations in technical efficiency, the choice of the regression equation in the previous stage will affect the outcome significantly.