• KDI Journal of Economic Policy
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• v.37 no.sup
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• pp.87-121
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• 2015

To attract more FDI inflows, the Korean government has designated several special economic zones (SEZs), offering various advantages and support to the FDI. There is, however, a shared acknowledgement that those efforts have gained little reward. In this regard, this paper empirically analyzes company-level performances of labor productivity, operating profit ratio, propensity to invest and innovate, etc. and then conducts regression analysis and PSM analysis to see whether these performances are meaningfully different between foreign-invested firm and domestic firm and between foreign-invested firms. The main findings of this paper are as follows. First, in the aspects of labor productivity and operating profit ratio, no empirical evidence was found to support the hypothesis that foreign-invested firm outperforms domestic firm in efficiency and profitability, Second, in the aspects of propensity to invest, foreign-invested firms in foreign investment zones outperformed domestic firms. Third, in the aspect of R&D investment, overall, foreign-invested firms showed a stronger propensity to invest than domestic firms, but there is no empirical evidence that high propensity to invest was driven by the policy on special economic zones. In the aspect of investment in educational training, empirical evidences were found that the role of foreign-invested firms outside the special zones turned out to be the strongest and that among firms inside special zones, it was those in the free economic zone that outperformed domestic firms. Lastly, foreign-invested firms showed a stronger propensity to employ than domestic firms, but there is no empirical evidence that high propensity to employ was driven by the policy on special economic zones.

• Journal of the Korean Geotechnical Society
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• v.20 no.7
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• pp.5-14
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• 2004

The observational design and construction method in tunnels is becoming important recently. In many tunnels, enormous cost and time are consumed to cope with the failing or sliding of rock blocks, which could not be predicted because of the complexity of rock discontinuities. It is difficult to estimate the properties of rock masses before the construction. In this paper, a new observational design and construction method in tunnels are proposed, and then applied to the example of the very large cross section tunnel based on actual discontinuity information observed in situ. The items examined in developing a program for the new observational design and construction method are the following ones: generality, precision, high speed, and friendly usability. At the very large cross section tunnel, 7 key blocks were judged to be unstable because they could not be supported by standard supports. Supplementary supports were installed to these 7 key blocks before the excavation. It is possible to detect key blocks all along the tunnel exactly by using the numerical analysis program developed for the new observational design and construction method in the very large cross section tunnel. This computer simulation method with user-friendly interfaces can calculate not only the stability of key blocks but also the design of supplementary supports.

• Journal of the Korean Geotechnical Society
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• v.21 no.9
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• pp.13-23
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• 2005

The prefabricated vertical drains (PVDs) are one of the most widely used techniques to accelerate the consolidation of soft clay deposits and dredged soil. Discharge capacity is one of the factors affecting the behavior of PVDs. In the field, a PVD is confined by clay or dredged soil, which is normally remolded during PVD installation. Under field conditions, soil particles may enter the PVD drainage channels, and the consolidation settlement of the improved subsoil may cause 131ding of the PVD. These factors will affect the discharge capacity of the PVDs. In this study an experimental study was carried out to estimate the discharge capacity of three different types of PVDs by utilizing the large-scale laboratory model testing and small-scale laboratory model testing equipments. The several factors such as confinement condition (confined by soft marine clay or dredged soil) and variations of the discharge capacity were studied with time under soil specimen confinement, The test results indicated that discharge capacity decreases with increasing load, time, and hydraulic gradient. With load application, the cross-sectional area of the drainage channel of PVD decreases because the filter of PVD is pressed into the core. The discharge capacity of the soft marine clay-confined PVDs is much lower than that of the dredged soil-confined PVDs.

• Journal of the Korean Geotechnical Society
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• v.21 no.6
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• pp.67-79
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• 2005

The field plate load test has a good potential for determining modulus since it measures both plate pressure and settlement. Conventionally the modulus has been assumed to be a constant secant value defined from the settlement of the plate at a given load intensity. A constant modulus (modulus of subgrade reaction, k), however, may not be a representative value of subgrade soil under working load. Field strain(o. stress)-dependent modulus characteristics of subgrade soils, at relatively low to intermediate strains, are important in the pavement design. In this study, the field strain dependent moduli of subgrade soils were obtained using cyclic plate load test. Testing procedure and data reduction method are proposed. The field crosshole and laboratory resonant column tests were also performed to determine field nonlinear modulus at $0.001\%\;to\;0.1\%$ strains, and the modulus values and nonlinear trends are compared to those obtained by cyclic plate load tests. Both modulus values match relatively well when the different state of stress between two tests was considered, and the applicability of field cyclic plate load test for determining nonlinear modulus values of subgrade soils is verified.

• Journal of the Korean Geotechnical Society
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• v.20 no.6
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• pp.127-136
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• 2004

The soil arching in the backfill, which affects the magnitude and distribution of active earth pressure on a retaining wall, has also an effect on the stability and cross-sectional area of the retaining wall. In this study, results obtained from Paik's equation that includes arching effect on active earth pressure are compared with those from Coulomb theory to investigate the influence of the soil arching on active earth pressure, overturning moment, stability and cross-sectional area of translating rigid retaining walls. The comparisons show that the active forces including arching effects are always higher than those from Coulomb theory, irrespective of $\phi$ and $\delta$ values. The overturning moments, shear force and moment on the rigid wall are also higher when considering arching effects than when not considering arching effects. The deviation of shear forces and moments by including and excluding arching effects becomes maximum at the height of 0.02-0.08 times wall height from the base of the wall. Therefore, if a translating rigid retaining walls is designed based on Coulomb theory, the wall may reach sliding and overturning failures due to arching effect in the backfill and the cross-sectional area of the wall, especially at lower part of the wall, may not be sufficient to resist to shear force and moment.

• Journal of the Korean Geotechnical Society
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• v.20 no.8
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• pp.103-111
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• 2004

There are some problems in evaluating the bearing capacity of decomposed granite soils by general equations on account of their inherent compressibility and crushability. In order to investigate this kind of the engineering characteristics on decomposed granite soils in detail, it is necessary to how the micro property of the single particle composing the granite soils, and then the relevance to the macro characteristics of the soils has to be cleared. The reason why the single particle properties are not studied is first the difficulty to find out some regulating parameters, and secondly little understanding of its significance. Furthermore, the water in the decomposed granite soils accelerates the particle crushing. Consequently, increasing of compressibility and decreasing of shear strength would occur. Actually, when the ground settlement is a big issue in the embanked ground using the decomposed granite soils, the sensitive change of compressibility due to the change of water content in the ground becomes conspicuous. In this study, the single particle strength characteristics are studied and microscopic particle shape analyses are performed. In addition the compressibility of the decomposed granite soils and water content effect on the compressibility are analysed based on the test results.

• Journal of Korean Home Economics Education Association
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• v.24 no.3
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• pp.89-100
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• 2012

The purposes of this study were to examine the overall tendency of perception of school environment and school adjustment in early adolescents during their transition from elementary to middle school. Also, examine the differences of adolescents' perception of school environment and school adjustment before and after entering secondary education. For this study, a total of 781 adolescents from middle school were asked to answer the questionnaire. And some objects of study, a total of 119 adolescents had answered in the same questionnaire content at the end of sixth grade of elementary school. The main findings were as followings. First, adolescents' perception of school environment during the transition to middle school was relatively good level, but perception of school safety appeared to be lower than average. Second, adolescents' school adjustment during the transition was comparatively good, particularly school life adjustment and school peer adjustment appeared to be above average. Third, there were significant positive relationships between perception of school environment and school adjustment. Fourth, adolescents' perception of school environment significantly decreased after they entered middle school, and significant differences were found in teacher support. Fifth, there were no differences in school adjustment before and after entering middle school, however school class adjustment and school life adjustment were significantly increased after the entrance into middle school.

• Journal of the Korean Geotechnical Society
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• v.29 no.3
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• pp.51-60
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• 2013

The slime, deposited in the bored pile due to falling soil particle, reduces the bearing capacity of bored pile and thus the stability of construction also decreases. The weight pendulum and iron have been used for estimating the slime thickness based on the subjective judgment and thus the previous method has a limitation of reliability. The objective of this paper is to suggest the method for estimating the slime thickness by using characteristics of electrical resistivity as scientific method. The temperature-compensation resistivity probe (TRP), which has a conical shape and the diameter of 35.7mm, is applied to the measurement of the electrical resistivity in the borehole during penetration. The field tests are carried out for estimating the slime thickness in the application site of bored pile. The slime thickness is calculated through the difference between excavation depth of borehole and measured data. Furthermore, the laboratory tests are also conducted for investigating effects of casing, time elapsing and relative density by using the specimen of slime. The laboratory test supporting the suggested method is reasonable for determining the slime depth. The paper suggests that the electrical resistivity method may be a useful method for detecting slime thickness and the method is expected to be applicable to various sites of bored piles.

• Journal of Hydrogen and New Energy
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• v.24 no.5
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• pp.359-366
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• 2013

This work is investigated for the catalytic decomposition of hydrogen iodide (HI). Platinum was used as active material by loading on $ZrO_2-SiO_2$ mixed oxide in HI decomposition reaction. To obtain high and stable conversion of hydrogen iodide in severe condition, it was required to improve catalytic activity. For this reason, a method increasing dispersion of platinum was proposed in this study. In order to get high dispersion of platinum, zirconia was incorporated in silica by sol-gel synthesis. Incorporating zirconia influence increasing platinum dispersion and BET surface area as well as decreasing deactivation of catalysts. It should be able to stably product hydrogen for a long time because of inhibitive deactivation. HI decomposition reaction was carried out under the condition of $450^{\circ}C$ and 1 atm in a fixed bed reactor. Catalysts analysis methods such as $N_2$ adsorption/desorption analysis, X-ray diffraction, X-ray fluorescence, ICP-AES and CO gas chemisorption were used to measurement of their physico-chemical properties.

• Journal of The Korean Association For Science Education
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• v.32 no.2
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• pp.201-209
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• 2012

This study aims to explore patterns and characteristics of coordination between evidence and theories which were found in pre-service elementary teachers' writing for their science inquiry. Five science inquiry activities and a total of 115 writings of the participant teacher at the elementary teacher preparation university in Korea were collected and analyzed for this study. Based on the writing analyses there were found four types of coordination between the evidence and theory. We proposed four types as: Type 1-Consistency of evidence and theory; Type 2-Consistence of evidence and theory including more extension or elaboration of theory; Type 3-Inconsistence of evidence and theory Type 4-Inconsistence of evidence and theory followed by coordination of them. Firstly the findings indicated that the most to least frequent types were Type 1, Type 3, Type 2, and Type 4. The most frequent type was Type 1. It is interpreted that theory in the inquiry questions were frequently figured out by participants and they selected supporting evidence out of data found. There were rarely found relations between activity topics and frequencies of coordination types except in activity 1. The findings in this study will connect to the point of how students collaborate their previously owned knowledge with experiment planning, data analysis and interpretation and making of their own scientific claims.